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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2016 Vol. 24, No. 10
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2016, 24(10): 1285-1299.
doi: 10.13930/j.cnki.cjea.160424
Abstract:
Exploring sink-source structures of high-yield rice varieties is generally significant for breeding practices. High- yield cultivation mode of large-scale rice production was determined based on sink-source characteristics of high-yield rice varieties, key indicators of ecological conditions, soil fertility of planted areas and high-yield cultivation techniques. As a result, it was not only saved manual labor and financial resources needed for the study of cultivation techniques of new varieties, but also accelerated the processes of demonstration and promotion of new varieties. In view of the reported data and research results of decades (over 20 years) of studies, sink-source structures of hybrid rice for high-yield varieties and the research progress on optimal control were summarized in this paper. The main results included: (1) High-yield rice varieties with 160–220 grains per panicle not only had coordinated contradictions between sinks and sources, but also improved photosynthetic efficiency. For big-panicle rice varieties, special attention was needed for the proper fertilizer application to increase grain filling and full use of the photosynthetic function of lower leaves in order to improve seed setting rate and 1000-grain weight. (2) A high-yield cultivation strategy of hybrid mid-rice with sparse cultivation was adopted with increased nitrogen application and photosynthetic source replenished so as to maintain normal grain filling under high grain-leaf ratio conditions. Increase in grain yield of upland rice seedlings over wet rice seedlings was significantly positively correlated with altitude, while it was significantly negatively correlated with yield of wet rice seedlings. Optimized application of nitrogen in hybrid rice was significantly influenced by ecological site conditions and soil nutrient states. Yield-increasing effects of the postponed nitrogen application and optimized application of nitrogen were strongly negatively correlated with soil fertility. Increase in grain yield was due to increased effective panicle number and 1000-grain weight. Highly significant negative correlations were noted between efficient nitrogen application (Y, kghm-2) for grain filling and SPAD value (X) of the first leaf from top at full panicle stage, Y = 30.798X + 1 340.9 and R2 = 0.911 4. A management technique of high-yield, water-saving rice was developed. (3) Transplanting density had significant negative correlation separately with grains number per panicle and applied N amount for varieties. There was significant effect of intensive cultivation system on yield increase, compared with traditional cultivation. A negative correlation was also noted between increased yield and grains number per panicle among varieties. Hybrid rice with less than 170 grains per panicle in traditional cultivation was suitable for intensive cultivation. Grain yield differences were caused by 2 different fertilization modes: nitrogen fertilizer shifted from basal tillering to panicle initiation (PBSP) stage and heavy basal N plus top-dressing at early tillering stage. Negative correlation was also observed between grain yield increase due to postponed nitrogen application difference (Y) and grains number per panicle (X), i.e., Y = 2 607.9 11.02X (R2 = 0.630 8). Hybrid rice cultivars with grains number per panicle less than 237 were suitable for PBSP fertilization. This research focused mainly on the theory and technique of optimal control of hybrid rice and then pointed out future research directions. The future researches should focuse on sink-source structures of hybrid rice varieties adaptable to mechanical transplanting and harvesting, early diagnosis and optimal fertilization techniques needed for high yields. Also early detection and prevention mechanisms of lodging and cultivation technique of hybrid rice were needed for reduced nitrogen use, increased yield and high-production efficiency.
Exploring sink-source structures of high-yield rice varieties is generally significant for breeding practices. High- yield cultivation mode of large-scale rice production was determined based on sink-source characteristics of high-yield rice varieties, key indicators of ecological conditions, soil fertility of planted areas and high-yield cultivation techniques. As a result, it was not only saved manual labor and financial resources needed for the study of cultivation techniques of new varieties, but also accelerated the processes of demonstration and promotion of new varieties. In view of the reported data and research results of decades (over 20 years) of studies, sink-source structures of hybrid rice for high-yield varieties and the research progress on optimal control were summarized in this paper. The main results included: (1) High-yield rice varieties with 160–220 grains per panicle not only had coordinated contradictions between sinks and sources, but also improved photosynthetic efficiency. For big-panicle rice varieties, special attention was needed for the proper fertilizer application to increase grain filling and full use of the photosynthetic function of lower leaves in order to improve seed setting rate and 1000-grain weight. (2) A high-yield cultivation strategy of hybrid mid-rice with sparse cultivation was adopted with increased nitrogen application and photosynthetic source replenished so as to maintain normal grain filling under high grain-leaf ratio conditions. Increase in grain yield of upland rice seedlings over wet rice seedlings was significantly positively correlated with altitude, while it was significantly negatively correlated with yield of wet rice seedlings. Optimized application of nitrogen in hybrid rice was significantly influenced by ecological site conditions and soil nutrient states. Yield-increasing effects of the postponed nitrogen application and optimized application of nitrogen were strongly negatively correlated with soil fertility. Increase in grain yield was due to increased effective panicle number and 1000-grain weight. Highly significant negative correlations were noted between efficient nitrogen application (Y, kghm-2) for grain filling and SPAD value (X) of the first leaf from top at full panicle stage, Y = 30.798X + 1 340.9 and R2 = 0.911 4. A management technique of high-yield, water-saving rice was developed. (3) Transplanting density had significant negative correlation separately with grains number per panicle and applied N amount for varieties. There was significant effect of intensive cultivation system on yield increase, compared with traditional cultivation. A negative correlation was also noted between increased yield and grains number per panicle among varieties. Hybrid rice with less than 170 grains per panicle in traditional cultivation was suitable for intensive cultivation. Grain yield differences were caused by 2 different fertilization modes: nitrogen fertilizer shifted from basal tillering to panicle initiation (PBSP) stage and heavy basal N plus top-dressing at early tillering stage. Negative correlation was also observed between grain yield increase due to postponed nitrogen application difference (Y) and grains number per panicle (X), i.e., Y = 2 607.9 11.02X (R2 = 0.630 8). Hybrid rice cultivars with grains number per panicle less than 237 were suitable for PBSP fertilization. This research focused mainly on the theory and technique of optimal control of hybrid rice and then pointed out future research directions. The future researches should focuse on sink-source structures of hybrid rice varieties adaptable to mechanical transplanting and harvesting, early diagnosis and optimal fertilization techniques needed for high yields. Also early detection and prevention mechanisms of lodging and cultivation technique of hybrid rice were needed for reduced nitrogen use, increased yield and high-production efficiency.
2016, 24(10): 1300-1309.
doi: 10.13930/j.cnki.cjea.151318
Abstract:
Biochar is a carbon-rich solid product obtained from heating biomass under oxygen-limited conditions. Biochar application has the potential to mitigate greenhouse gas emission. Dryland farming areas in Northwest China emit substantial amounts of greenhouse gases. The aim of this study was to determine the effects of different biochar rates on diurnal variations in methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) emissions in the western Loess Plateau. Treatments included 6 biochar application rates (3 replications): 0 t·hm2 (control, B0), 10 t·hm2 (B1), 20 t·hm2 (B2), 30 t·hm2 (B3), 40 t·hm2 (B4) and 50 t·hm2 (B5) t·hm2. Soil moisture and temperature were measured concurrently with gas measurement. The results showed distinct diurnal variations in CO2, CH4 and N2O fluxes for different biochar application rates. The trends of change in the fluxes of the 3 gases (CH4, N2O and CO2) were consistent with daily variations in temperature. Daytime fluxes were greater than nighttime fluxes. The order of absorption peak of CH4 was B0 (10.14ug·m-2·h-1) > B1 (7.82 ug·m-2·h-1) > B2 (6.57 ug·m-2·h-1) > B5 (2.89 ug·m-2·h-1) > B4 (1.05 ug·m-2·h-1) > B3 (0.10 ug·m-2·h-1). A similar order was noted for average emission flux of N2O, given as B0 (288.79 ug·m-2·h-1) > B1 (201.78 ug·m-2·h-1) > B5 (164.02 ug·m-2·h-1) > B2 (157.14 ug·m-2·h-1) > B4 (154.60 ug·m-2·h-1) > B3 (112.06 ug·m-2·h-1). The order of average emission flux of CO2 was B0 (85.44 mg·m-2·h-1) > B1 (80.91 mg·m-2·h-1) > B2 (76.49 mg·m-2·h-1) > B5 (69.10 mg·m-2·h-1) > B4 (67.19 mg·m-2·h-1) > B3 (65.29 mg·m-2·h-1). The results showed that when biochar input was less than 30 t·hm2, mean emission fluxes of CH4, N2O and CO2 dropped with increasing biochar application rate. However, when biochar input exceed 30 t·hm2, the mean emission fluxes of CH4, N2O and CO2 increased with increasing biochar application rate. The soil was a good source of atmospheric CH4 for all treatments (except for 30 t·hm2) and sources of atmospheric N2O and CO2, irrespective of treatment. Soil temperature at 5 cm depth was correlated with biochar application rate — y = 0.017 6x + 16.585 (R2 = 0.302 6, r = 0.55, P < 0.05), but soil moisture at 5 cm soil depth was linearly correlated with biochar application rate — y = 0.056 5x + 13.626 (R2=0.815 1, r = 0.903, P < 0.05). The average fluxes of CH4, N2O and CO2 under the control treatment were positively correlated with soil temperature of both soil surface and the 05 cm depth. The others treatments were also positively correlated with different levels of biochar. Biochar application at 30 t·hm2 reduced greenhouse gas emission. The differences in both soil temperature and moisture caused by different input levels of biochar were the main reasons for the differences in CH4, N2O and CO2 emissions. Correction coefficient and regression analysis of optimal measure time revealed that the optimal observation period of the three greenhouse gases was between 8 a.m. and 9 a.m.
Biochar is a carbon-rich solid product obtained from heating biomass under oxygen-limited conditions. Biochar application has the potential to mitigate greenhouse gas emission. Dryland farming areas in Northwest China emit substantial amounts of greenhouse gases. The aim of this study was to determine the effects of different biochar rates on diurnal variations in methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) emissions in the western Loess Plateau. Treatments included 6 biochar application rates (3 replications): 0 t·hm2 (control, B0), 10 t·hm2 (B1), 20 t·hm2 (B2), 30 t·hm2 (B3), 40 t·hm2 (B4) and 50 t·hm2 (B5) t·hm2. Soil moisture and temperature were measured concurrently with gas measurement. The results showed distinct diurnal variations in CO2, CH4 and N2O fluxes for different biochar application rates. The trends of change in the fluxes of the 3 gases (CH4, N2O and CO2) were consistent with daily variations in temperature. Daytime fluxes were greater than nighttime fluxes. The order of absorption peak of CH4 was B0 (10.14ug·m-2·h-1) > B1 (7.82 ug·m-2·h-1) > B2 (6.57 ug·m-2·h-1) > B5 (2.89 ug·m-2·h-1) > B4 (1.05 ug·m-2·h-1) > B3 (0.10 ug·m-2·h-1). A similar order was noted for average emission flux of N2O, given as B0 (288.79 ug·m-2·h-1) > B1 (201.78 ug·m-2·h-1) > B5 (164.02 ug·m-2·h-1) > B2 (157.14 ug·m-2·h-1) > B4 (154.60 ug·m-2·h-1) > B3 (112.06 ug·m-2·h-1). The order of average emission flux of CO2 was B0 (85.44 mg·m-2·h-1) > B1 (80.91 mg·m-2·h-1) > B2 (76.49 mg·m-2·h-1) > B5 (69.10 mg·m-2·h-1) > B4 (67.19 mg·m-2·h-1) > B3 (65.29 mg·m-2·h-1). The results showed that when biochar input was less than 30 t·hm2, mean emission fluxes of CH4, N2O and CO2 dropped with increasing biochar application rate. However, when biochar input exceed 30 t·hm2, the mean emission fluxes of CH4, N2O and CO2 increased with increasing biochar application rate. The soil was a good source of atmospheric CH4 for all treatments (except for 30 t·hm2) and sources of atmospheric N2O and CO2, irrespective of treatment. Soil temperature at 5 cm depth was correlated with biochar application rate — y = 0.017 6x + 16.585 (R2 = 0.302 6, r = 0.55, P < 0.05), but soil moisture at 5 cm soil depth was linearly correlated with biochar application rate — y = 0.056 5x + 13.626 (R2=0.815 1, r = 0.903, P < 0.05). The average fluxes of CH4, N2O and CO2 under the control treatment were positively correlated with soil temperature of both soil surface and the 05 cm depth. The others treatments were also positively correlated with different levels of biochar. Biochar application at 30 t·hm2 reduced greenhouse gas emission. The differences in both soil temperature and moisture caused by different input levels of biochar were the main reasons for the differences in CH4, N2O and CO2 emissions. Correction coefficient and regression analysis of optimal measure time revealed that the optimal observation period of the three greenhouse gases was between 8 a.m. and 9 a.m.
2016, 24(10): 1310-1319.
doi: 10.13930/j.cnki.cjea.160258
Abstract:
Humic acid-urea is an innovated fertilizer used widely in agricultural production in recent years. However, understanding on nutrient use efficiency of humic acid-urea under wheat-maize rotation system and its driving factors has so far been limited. In this study, the effects of activated humic acid-urea on wheat and maize growth, soil physicochemical properties, nitrogen use efficiency, soil nitrogen forms and contents were investigated in both field and incubation experiments. Three activated humic acid-urea treatments used in the experiments included mixed humic acid and urea (U+HA1), activated humic acid-urea (U+HA2) and activated and catalyzed humic acid-urea (U+HA3). For comparison with those urea treatments, no fertilizer application treatment (Control) and single urea application (Urea) were set up. Wheat and maize grain yields in U+HA2 and U+HA3 treatments were enhanced respectively by 15%–28% and 8%–10%, compared with Urea treatment. The application of activated humic acid-urea not only significantly reduced soil bulk density, pH and center diameter of soil granule, but also significantly increased soil specific surface area, electrical conductivity, organic carbon concentration and mineral nitrogen content. In wheat season, nitrogen recovery efficiencies with activated humic acid-urea treatments were markedly higher than that of Urea treatment. The rate of increase for wheat was 37%–91% and that for maize was 78%–93%. The trends in nitrogen agronomic efficiency and nitrogen partial productivity were then same for activated humic acid-urea treatments under wheat-maize rotation system. In addition, regression analysis showed that nitrogen recovery efficiency decreased with increasing soil nitrification, soil organic nitrogen mineralization and soil urease activity. However, it increased with increasing soil specific surface area. In the study, U+HA3 was the best treatment for crop yield, soil physicochemical properties, etc., which was therefore recommended for application in agricultural production. The results of the study provided the basis for the development and promotion of activated humic acid-urea used in agriculture.
Humic acid-urea is an innovated fertilizer used widely in agricultural production in recent years. However, understanding on nutrient use efficiency of humic acid-urea under wheat-maize rotation system and its driving factors has so far been limited. In this study, the effects of activated humic acid-urea on wheat and maize growth, soil physicochemical properties, nitrogen use efficiency, soil nitrogen forms and contents were investigated in both field and incubation experiments. Three activated humic acid-urea treatments used in the experiments included mixed humic acid and urea (U+HA1), activated humic acid-urea (U+HA2) and activated and catalyzed humic acid-urea (U+HA3). For comparison with those urea treatments, no fertilizer application treatment (Control) and single urea application (Urea) were set up. Wheat and maize grain yields in U+HA2 and U+HA3 treatments were enhanced respectively by 15%–28% and 8%–10%, compared with Urea treatment. The application of activated humic acid-urea not only significantly reduced soil bulk density, pH and center diameter of soil granule, but also significantly increased soil specific surface area, electrical conductivity, organic carbon concentration and mineral nitrogen content. In wheat season, nitrogen recovery efficiencies with activated humic acid-urea treatments were markedly higher than that of Urea treatment. The rate of increase for wheat was 37%–91% and that for maize was 78%–93%. The trends in nitrogen agronomic efficiency and nitrogen partial productivity were then same for activated humic acid-urea treatments under wheat-maize rotation system. In addition, regression analysis showed that nitrogen recovery efficiency decreased with increasing soil nitrification, soil organic nitrogen mineralization and soil urease activity. However, it increased with increasing soil specific surface area. In the study, U+HA3 was the best treatment for crop yield, soil physicochemical properties, etc., which was therefore recommended for application in agricultural production. The results of the study provided the basis for the development and promotion of activated humic acid-urea used in agriculture.
2016, 24(10): 1320-1327.
doi: 10.13930/j.cnki.cjea.160384
Abstract:
The effects of new fertilizers on the yield, quality, photosynthetic characteristics and fertilizer utilization of Chinese cabbage in Guizhou acid yellow soils were investigated in a pot experiment. The soil used in the experiment was typical yellow soil with pH 6.08, collected from the experimental base of Academy of Agricultural Sciences of Guizhou. The four treatments studied in the experiment included the contrast treatment (CK, no nitrogen fertilizer), compound fertilizer (FH, conventional fertilizer), water retaining fertilizer (BS) and stable slow-release fertilizer (WD). The biomass, contents of nitrate, reducing sugar, Vc and free amino acid as well as leaf gas exchange parameters and nitrogen content and utilization of Chinese cabbage were investigated at different times after sowing. The results showed that at 34 days after sowing, BS and WD treatments significantly increased Chinese cabbage biomass. Compared with FH treatment, BS and WD treatments increased Chinese cabbage fresh weights by 4.16% and 41.55%, and dry weights by 22.28% and 62.35%, respectively. Application of new fertilizers also improved nutritional quality of Chinese cabbage. Compared with FH treatment, BS treatment significantly reduced nitrate content by 18.61% while increased contents of reducing sugar, Vc and free amino acid, respectively, by 25.74%, 130.95% and 16.91%. However, WD treatment increased nitrate, reducing sugar and Vc contents, respectively, by 26.68%, 15.35% and 50.00%, while decreased free amino acid content by 14.43%. The application of the new fertilizers also enhanced the photosynthetic capacity of Chinese cabbage leaves, including the net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr), forwhich WD treatment had the best performance. The stomata regulation was the main enhancement factor for photosynthetic capacity. Nitrogen uptake of Chinese cabbage obviously increased and nitrogen use efficiency apparently enhanced as well. Average agronomic nitrogen efficiency (AEN), partial factor productivity (PFPN), physiological utilization (PEN) and recovery efficiency (REN) for new fertilizer treatments were respectively 48.30 kg.kg-1, 59.85kg.kg-1, 95.46 kg.kg-1 and 52.79%. Then the treatment with the best efficiency was WD treatment, especially for nitrogen recovery efficiency (which was 66.66%). Correlation analysis showed that yield and net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) had significant positive correlations. This suggested that improvement in net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) increased yield of Chinese cabbage. Concurrently, there was a significant correlation between nitrogen content, physiological utilization (PEN) and recovery efficiency (REN), with r values of 0.937 and 0.978, respectively. This suggested that increase in nitrogen content improved nitrogen utilization efficiency. Furthermore, the new fertilizers significantly enhanced biological yield and photosynthetic characteristics of Chinese cabbage in Guizhou acid yellow soils. The study laid a solid scientific reference and theoretical basis for future applications of new fertilizers in agricultural production in Guizhou Province.
The effects of new fertilizers on the yield, quality, photosynthetic characteristics and fertilizer utilization of Chinese cabbage in Guizhou acid yellow soils were investigated in a pot experiment. The soil used in the experiment was typical yellow soil with pH 6.08, collected from the experimental base of Academy of Agricultural Sciences of Guizhou. The four treatments studied in the experiment included the contrast treatment (CK, no nitrogen fertilizer), compound fertilizer (FH, conventional fertilizer), water retaining fertilizer (BS) and stable slow-release fertilizer (WD). The biomass, contents of nitrate, reducing sugar, Vc and free amino acid as well as leaf gas exchange parameters and nitrogen content and utilization of Chinese cabbage were investigated at different times after sowing. The results showed that at 34 days after sowing, BS and WD treatments significantly increased Chinese cabbage biomass. Compared with FH treatment, BS and WD treatments increased Chinese cabbage fresh weights by 4.16% and 41.55%, and dry weights by 22.28% and 62.35%, respectively. Application of new fertilizers also improved nutritional quality of Chinese cabbage. Compared with FH treatment, BS treatment significantly reduced nitrate content by 18.61% while increased contents of reducing sugar, Vc and free amino acid, respectively, by 25.74%, 130.95% and 16.91%. However, WD treatment increased nitrate, reducing sugar and Vc contents, respectively, by 26.68%, 15.35% and 50.00%, while decreased free amino acid content by 14.43%. The application of the new fertilizers also enhanced the photosynthetic capacity of Chinese cabbage leaves, including the net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr), forwhich WD treatment had the best performance. The stomata regulation was the main enhancement factor for photosynthetic capacity. Nitrogen uptake of Chinese cabbage obviously increased and nitrogen use efficiency apparently enhanced as well. Average agronomic nitrogen efficiency (AEN), partial factor productivity (PFPN), physiological utilization (PEN) and recovery efficiency (REN) for new fertilizer treatments were respectively 48.30 kg.kg-1, 59.85kg.kg-1, 95.46 kg.kg-1 and 52.79%. Then the treatment with the best efficiency was WD treatment, especially for nitrogen recovery efficiency (which was 66.66%). Correlation analysis showed that yield and net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) had significant positive correlations. This suggested that improvement in net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) increased yield of Chinese cabbage. Concurrently, there was a significant correlation between nitrogen content, physiological utilization (PEN) and recovery efficiency (REN), with r values of 0.937 and 0.978, respectively. This suggested that increase in nitrogen content improved nitrogen utilization efficiency. Furthermore, the new fertilizers significantly enhanced biological yield and photosynthetic characteristics of Chinese cabbage in Guizhou acid yellow soils. The study laid a solid scientific reference and theoretical basis for future applications of new fertilizers in agricultural production in Guizhou Province.
2016, 24(10): 1328-1338.
doi: 10.13930/j.cnki.cjea.160388
Abstract:
To study the effects of planting density and seeding method on agronomic trait, yield and quality of peanut and to determine optimal planting density and seeding method for peanut in saline soils, a peanut (Huayu 25, salt-tolerant cultivar) field plot experiment containing five single-seed planting density treatments and three double-seeds planting density treatments was conducted. Experiment 1 was the single-seed planting experiment containing 5 planting densities — 180 thousand hole·hm-2 (M1), 196 thousand hole·hm-2 (M2), 214 thousand hole·hm-2 (M3), 235 thousand hole·hm-2 (M4) and 260 thousand hole·hm-2 (M5), respectively. Experiment 2 was the double-seed planting experiment, consisting of 3 planting densities — 116 thousand hole·hm-2 (M6), 130 thousand hole·hm-2 (M7) and 147 thousand hole·hm-2 (M8). The results showed that soil salinity stress greatly inhibited the growth of peanut plant. Compared with peanut in non-saline soils, peanut stem and branch length reduced significantly, which were 25.6 cm and 29.0 cm, respectively. For single-seed planting in the density range of 196260 thousand hole·hm-2, the height of stem and length of branch significantly reduced with increasing planting density before pod-filling stage. Before pod-swelling and after pod-filling stage, the numbers of primary and secondary branch of single-seed planting were higher than that of double-seed planting in the range of M2M4. The stem base length decreased with increasing density, but the difference was not significant. Changes in length and thickness of stem base mainly occurred before pod-setting stage, and the rate of stem elongation was faster than the rate of cross-sectional area increase. The length and thickness of stem base tended to stabilize at late growth stage. The period of rapid accumulation of photosynthetic products in the leaves, stems and petioles of peanut in saline soils was mainly at flowering, pegging and pod swelling stages. The maximum growth rate (Vm) of leaves was only half of that of stems and petioles. The rapid growth stage leaves was 5 days earlier than that of stems and petioles. Also the Vm time of leaves, stems and petioles under the single-seed planting lagged behind that under double-seed planting. Peanut shoot Vm characterized by “parabola type” changed with increasing planting density. The leaves, stems and petioles of Vm were largest under M4 treatment, which were 0.492 5 g per plant and 0.878 3 g per plant, respectively. The effect of planting density on the accumulation of photosynthetic products in peanut was more significant, but the distribution rate of each organ in each period was not significantly different. Peanut photosynthetic products in saline soils were roughly identical to those in non-saline soils. Photosynthetic products were in the stems and leaves at the early growth stage and a third of the photosynthetic products was at pods at pod to pod-filling stage. The effect of planting density on pod yield was significant under single-seed planting, but was not significant on kernel soluble sugar, protein, fat, and the ratio of oleic and linoleic acid. For the single-seed planting, the optimum density was 190235 thousand hole·hm-2.
To study the effects of planting density and seeding method on agronomic trait, yield and quality of peanut and to determine optimal planting density and seeding method for peanut in saline soils, a peanut (Huayu 25, salt-tolerant cultivar) field plot experiment containing five single-seed planting density treatments and three double-seeds planting density treatments was conducted. Experiment 1 was the single-seed planting experiment containing 5 planting densities — 180 thousand hole·hm-2 (M1), 196 thousand hole·hm-2 (M2), 214 thousand hole·hm-2 (M3), 235 thousand hole·hm-2 (M4) and 260 thousand hole·hm-2 (M5), respectively. Experiment 2 was the double-seed planting experiment, consisting of 3 planting densities — 116 thousand hole·hm-2 (M6), 130 thousand hole·hm-2 (M7) and 147 thousand hole·hm-2 (M8). The results showed that soil salinity stress greatly inhibited the growth of peanut plant. Compared with peanut in non-saline soils, peanut stem and branch length reduced significantly, which were 25.6 cm and 29.0 cm, respectively. For single-seed planting in the density range of 196260 thousand hole·hm-2, the height of stem and length of branch significantly reduced with increasing planting density before pod-filling stage. Before pod-swelling and after pod-filling stage, the numbers of primary and secondary branch of single-seed planting were higher than that of double-seed planting in the range of M2M4. The stem base length decreased with increasing density, but the difference was not significant. Changes in length and thickness of stem base mainly occurred before pod-setting stage, and the rate of stem elongation was faster than the rate of cross-sectional area increase. The length and thickness of stem base tended to stabilize at late growth stage. The period of rapid accumulation of photosynthetic products in the leaves, stems and petioles of peanut in saline soils was mainly at flowering, pegging and pod swelling stages. The maximum growth rate (Vm) of leaves was only half of that of stems and petioles. The rapid growth stage leaves was 5 days earlier than that of stems and petioles. Also the Vm time of leaves, stems and petioles under the single-seed planting lagged behind that under double-seed planting. Peanut shoot Vm characterized by “parabola type” changed with increasing planting density. The leaves, stems and petioles of Vm were largest under M4 treatment, which were 0.492 5 g per plant and 0.878 3 g per plant, respectively. The effect of planting density on the accumulation of photosynthetic products in peanut was more significant, but the distribution rate of each organ in each period was not significantly different. Peanut photosynthetic products in saline soils were roughly identical to those in non-saline soils. Photosynthetic products were in the stems and leaves at the early growth stage and a third of the photosynthetic products was at pods at pod to pod-filling stage. The effect of planting density on pod yield was significant under single-seed planting, but was not significant on kernel soluble sugar, protein, fat, and the ratio of oleic and linoleic acid. For the single-seed planting, the optimum density was 190235 thousand hole·hm-2.
2016, 24(10): 1339-1346.
doi: 10.13930/j.cnki.cjea.160182
Abstract:
Precise and prompt approach of crop nutrient diagnosis is the prerequisite in determining crop N content and the recommendation of reasonable amount of N fertilizer. In this study, a field experiment was carried out under drip irrigation condition, the chlorophyll equipment (SPAD-502 Plus) and nitrate reflectrometer (RQ flex10) was employed in terms of diagnosis of maize N nutrition during key growth stages. The aim of the study was to build maize fertilization mode by using the most suitable diagnosis approach. Five N fertilizer application rates were arrayed, including N0 [0 kg(N).hm-2], N225 [225 kg(N).hm-2], N330 [330 kg(N).hm-2], N435 [435 kg(N).hm-2] and N540 [540 kg(N).hm-2]. The difference of diagnostic effect between SPAD-502 Plus and RQ flex10 methods on maize plant N nutrient were compared based on correlation analysis. The analysis compared the relationships between corn leaf SPAD and leaf sheath NO3 concentration for various N fertilizer application rates, plant total N content and yield during different maize growth stages. Also the sensitivities of the RQ flex 10 and SPAD methods of diagnosis of maize plant N nutrient were compared. The results were as follows: 1) Maize leaf SPAD and leaf sheath NO3- concentration significantly increased with increasing N fertilizer application rate and the most sensitive period was from jointing stage to either tassel-emergence stage or grain-filling stage. The response of sheath NO3- concentration to N application rate was more sensitive than that of SPAD. This resulted into a higher degree of fit between NO3- concentration determined by RQ flex 10 method and N application rate or maize yield. RQ flex 10 method was more sensitive in diagnosis of maize N nutrition. 2) The total N content in maize had a significant linear correlation with leaf SPAD, while there was linear and then a constant correlation between the total N and sheath NO3- concentration. That was, total N content was linearly correlated with NO3- concentration as corn sheath NO3- concentration less than 186 mg·L-1, however, total N content varied slight when sheath NO3- concentration exceeding 186 mg·L-1 . 3) The recommended economic fertilizer application rate in maize under drip irrigation was 402.5 kg·hm-2, which produced a yield of 17 049 kg·hm-2. The critical NO3- concentration was 729.3 mg·L-1 at jointing stage, 536 mg·L-1 at tassel emergence stage and 81.2 mg·L-1 at grouting stage, respectively. In conclusion, our study showed that both the chlorophyll meter and RQ flex 10 were suitable for maize N nutrient diagnosis. Moreover, the RQ flex 10 approach was a more sensitive method than the chlorophyll meter in diagnosing maize N nutrient status. The study suggested that the RQ flex method was highly suitable for the recommendation of N fertilizer as well as better N resource management in maize fields.
Precise and prompt approach of crop nutrient diagnosis is the prerequisite in determining crop N content and the recommendation of reasonable amount of N fertilizer. In this study, a field experiment was carried out under drip irrigation condition, the chlorophyll equipment (SPAD-502 Plus) and nitrate reflectrometer (RQ flex10) was employed in terms of diagnosis of maize N nutrition during key growth stages. The aim of the study was to build maize fertilization mode by using the most suitable diagnosis approach. Five N fertilizer application rates were arrayed, including N0 [0 kg(N).hm-2], N225 [225 kg(N).hm-2], N330 [330 kg(N).hm-2], N435 [435 kg(N).hm-2] and N540 [540 kg(N).hm-2]. The difference of diagnostic effect between SPAD-502 Plus and RQ flex10 methods on maize plant N nutrient were compared based on correlation analysis. The analysis compared the relationships between corn leaf SPAD and leaf sheath NO3 concentration for various N fertilizer application rates, plant total N content and yield during different maize growth stages. Also the sensitivities of the RQ flex 10 and SPAD methods of diagnosis of maize plant N nutrient were compared. The results were as follows: 1) Maize leaf SPAD and leaf sheath NO3- concentration significantly increased with increasing N fertilizer application rate and the most sensitive period was from jointing stage to either tassel-emergence stage or grain-filling stage. The response of sheath NO3- concentration to N application rate was more sensitive than that of SPAD. This resulted into a higher degree of fit between NO3- concentration determined by RQ flex 10 method and N application rate or maize yield. RQ flex 10 method was more sensitive in diagnosis of maize N nutrition. 2) The total N content in maize had a significant linear correlation with leaf SPAD, while there was linear and then a constant correlation between the total N and sheath NO3- concentration. That was, total N content was linearly correlated with NO3- concentration as corn sheath NO3- concentration less than 186 mg·L-1, however, total N content varied slight when sheath NO3- concentration exceeding 186 mg·L-1 . 3) The recommended economic fertilizer application rate in maize under drip irrigation was 402.5 kg·hm-2, which produced a yield of 17 049 kg·hm-2. The critical NO3- concentration was 729.3 mg·L-1 at jointing stage, 536 mg·L-1 at tassel emergence stage and 81.2 mg·L-1 at grouting stage, respectively. In conclusion, our study showed that both the chlorophyll meter and RQ flex 10 were suitable for maize N nutrient diagnosis. Moreover, the RQ flex 10 approach was a more sensitive method than the chlorophyll meter in diagnosing maize N nutrient status. The study suggested that the RQ flex method was highly suitable for the recommendation of N fertilizer as well as better N resource management in maize fields.
2016, 24(10): 1347-1355.
doi: 10.13930/j.cnki.cjea.160130
Abstract:
Excessive application of nitrogen (N) fertilizers leads to nitrogen loss and increases the cost of agricultural production. Screening rice cultivars with high N efficiency is an effective approach to improving N use efficiency and reducing environmental pollution. In this paper, hydroponic experiments were conducted to examine the differences in N absorption and accumulation of 55 rice cultivars (lines) at seedling stage. The experiments used the same N dose of 40 mgL1 in the form of both NH4+-N and NO3–-N and the evaluation indices standardized using subordinate function of interval [0, 1]. The 55 rice cultivars (lines) were classified based on N use efficiency and hierarchical cluster analysis. There were significant differences in aboveground biomass, including whole plant stem, leaf and root, as well as N content in roots, stems and leaves of the rice cultivars (lines) between treated with NH4+-N and NO3–-N (P < 0.05). Also the ranges of coefficients of variation were 0.690.80 and 0.570.74, respectively, for NH4+-N and NO3–-N treatments. Factor analysis showed that the principal com- ponents of the NH4+-N and NO3–-N treatments were the same. The first principal component was mainly reflected biomass indices and N accumulation, determined using the whole plant, stem, leaf and root biomass, as well as accumulated N in the whole plant, stem and leaf and root. The second principal component was determined using N content. By combining variation characteristics and factor analysis of N uptake and accumulation in rice, the whole plant biomass, stem and leaf biomass, root biomass, stem and leaf N accumulation were used as indices to evaluate high N use efficiency potentials of rice cultivars (lines) at seedling stage. Calculation of the comprehensive values of N use efficiency, based on the membership function method and fitted hierarchical clustering chart of squared Euclidean distance, showed that the 55 rice cultivars (lines) grouped into three categories — high, medium and low N use efficiencies. Rice cultivars (lines) with high, medium and low N use efficiencies with NH4+-N and NO3–-N treatments accounted for 10.91%, 27.27% and 61.82% of the total rice cultivars (lines), respectively. The whole plant biomass, stem and leaf biomass, root biomass, stem and leaf N accumulation could be used as indices to evaluate the N use efficiency potentials of rice cultivars (lines) at seedling stage. ‘Guangliangyou 3905’, ‘Yongyou 9’, ‘Zhongxian 2503’, ‘Ⅱyou 602’, ‘Liangyou 766’ and ‘Shenliangyou 1813’ rice cultivars had high N use efficiency under both NH4+-N and NO3–-N treatments.
Excessive application of nitrogen (N) fertilizers leads to nitrogen loss and increases the cost of agricultural production. Screening rice cultivars with high N efficiency is an effective approach to improving N use efficiency and reducing environmental pollution. In this paper, hydroponic experiments were conducted to examine the differences in N absorption and accumulation of 55 rice cultivars (lines) at seedling stage. The experiments used the same N dose of 40 mgL1 in the form of both NH4+-N and NO3–-N and the evaluation indices standardized using subordinate function of interval [0, 1]. The 55 rice cultivars (lines) were classified based on N use efficiency and hierarchical cluster analysis. There were significant differences in aboveground biomass, including whole plant stem, leaf and root, as well as N content in roots, stems and leaves of the rice cultivars (lines) between treated with NH4+-N and NO3–-N (P < 0.05). Also the ranges of coefficients of variation were 0.690.80 and 0.570.74, respectively, for NH4+-N and NO3–-N treatments. Factor analysis showed that the principal com- ponents of the NH4+-N and NO3–-N treatments were the same. The first principal component was mainly reflected biomass indices and N accumulation, determined using the whole plant, stem, leaf and root biomass, as well as accumulated N in the whole plant, stem and leaf and root. The second principal component was determined using N content. By combining variation characteristics and factor analysis of N uptake and accumulation in rice, the whole plant biomass, stem and leaf biomass, root biomass, stem and leaf N accumulation were used as indices to evaluate high N use efficiency potentials of rice cultivars (lines) at seedling stage. Calculation of the comprehensive values of N use efficiency, based on the membership function method and fitted hierarchical clustering chart of squared Euclidean distance, showed that the 55 rice cultivars (lines) grouped into three categories — high, medium and low N use efficiencies. Rice cultivars (lines) with high, medium and low N use efficiencies with NH4+-N and NO3–-N treatments accounted for 10.91%, 27.27% and 61.82% of the total rice cultivars (lines), respectively. The whole plant biomass, stem and leaf biomass, root biomass, stem and leaf N accumulation could be used as indices to evaluate the N use efficiency potentials of rice cultivars (lines) at seedling stage. ‘Guangliangyou 3905’, ‘Yongyou 9’, ‘Zhongxian 2503’, ‘Ⅱyou 602’, ‘Liangyou 766’ and ‘Shenliangyou 1813’ rice cultivars had high N use efficiency under both NH4+-N and NO3–-N treatments.
2016, 24(10): 1356-1363.
doi: 10.13930/j.cnki.cjea.160153
Abstract:
Solar greenhouse, developed by China’s farmers and scientists in the early 1980s, makes it possible to produce vegetables during winter without additional heating and lighting in large parts of North China. Vegetable cultivation in greenhouses has high profitability. This has led to a rapid increase in the land area used for solar greenhouse production over the last three decades. Within the greenhouse system, it is common to overuse inorganic fertilizers and manure in vegetable production. It increases the organic matter in soil and the accumulation of nutrients and salts in the soil. The accumulation of nutrients in solar greenhouse soils, especially nitrate, has high environmental risks. Optimum application of nitrogen (N) fertilizer is critical for resolving this problem. Mineralized N in soils during crop growth supports a high rate of N uptake by crop. Therefore understanding nitrogen (N) mineralization in solar greenhouse soils with different cultivation histories is important for rational N fertilization. However, most of the studies on soil N mineralization studies have focused on arable soils and little remains known about N mineralization in solar greenhouse soils with different cultivation histories. In this study, the pot depletion method and Stanford and Smith aerobic incubation method were used to evaluate the effects of cultivation years on N supply ability in the 020 cm layer of soil under newly-built solar greenhouse with different cultivation years [0 year (before greenhouse construction), 2 and 3 years] of operation in Yangling, Shaanxi. Response of tomato to cultivation years was also investigated. The results showed that tomato height, stem diameter, aboveground and root biomass, leaf SPAD in 2 and 3 years greenhouse were significantly higher than those in field of 0 year greenhouse, while these indexes were not significantly different between 2 years and 3 years greenhouses. Total N uptake of tomato increased with increasing age of solar greenhouse. Total N uptakes in greenhouse soils with 2 and 3 years of cultivation were 2.53 and 3.01 times that of soils before greenhouse construction. Soil organic matter, total nitrogen and available nutrients contents of 3 years solar greenhouse were significantly increased compared with those of field before greenhouse construction. Mineralized N in solar greenhouse soils with 2 and 3 years of cultivation was 2.84 and 2.96 times that of soils before greenhouse construction. It then indicated that as the age of solar greenhouse increased, soil N supply ability increased significantly. The contents of soil organic matter, total N, initial mineral N, and mineralized N were significantly positively related to tomato N uptake. The coefficient between mineralized N and tomato N uptake was highest. It indicated that these indexes could be used to evaluate soil N supply ability, mineralized N was the best one. In order to reduce N loss and increase N use efficiency in the study area, it was concluded that as the age of greenhouses increased, the addition of inorganic N fertilizer should be reduced in solar greenhouse production.
Solar greenhouse, developed by China’s farmers and scientists in the early 1980s, makes it possible to produce vegetables during winter without additional heating and lighting in large parts of North China. Vegetable cultivation in greenhouses has high profitability. This has led to a rapid increase in the land area used for solar greenhouse production over the last three decades. Within the greenhouse system, it is common to overuse inorganic fertilizers and manure in vegetable production. It increases the organic matter in soil and the accumulation of nutrients and salts in the soil. The accumulation of nutrients in solar greenhouse soils, especially nitrate, has high environmental risks. Optimum application of nitrogen (N) fertilizer is critical for resolving this problem. Mineralized N in soils during crop growth supports a high rate of N uptake by crop. Therefore understanding nitrogen (N) mineralization in solar greenhouse soils with different cultivation histories is important for rational N fertilization. However, most of the studies on soil N mineralization studies have focused on arable soils and little remains known about N mineralization in solar greenhouse soils with different cultivation histories. In this study, the pot depletion method and Stanford and Smith aerobic incubation method were used to evaluate the effects of cultivation years on N supply ability in the 020 cm layer of soil under newly-built solar greenhouse with different cultivation years [0 year (before greenhouse construction), 2 and 3 years] of operation in Yangling, Shaanxi. Response of tomato to cultivation years was also investigated. The results showed that tomato height, stem diameter, aboveground and root biomass, leaf SPAD in 2 and 3 years greenhouse were significantly higher than those in field of 0 year greenhouse, while these indexes were not significantly different between 2 years and 3 years greenhouses. Total N uptake of tomato increased with increasing age of solar greenhouse. Total N uptakes in greenhouse soils with 2 and 3 years of cultivation were 2.53 and 3.01 times that of soils before greenhouse construction. Soil organic matter, total nitrogen and available nutrients contents of 3 years solar greenhouse were significantly increased compared with those of field before greenhouse construction. Mineralized N in solar greenhouse soils with 2 and 3 years of cultivation was 2.84 and 2.96 times that of soils before greenhouse construction. It then indicated that as the age of solar greenhouse increased, soil N supply ability increased significantly. The contents of soil organic matter, total N, initial mineral N, and mineralized N were significantly positively related to tomato N uptake. The coefficient between mineralized N and tomato N uptake was highest. It indicated that these indexes could be used to evaluate soil N supply ability, mineralized N was the best one. In order to reduce N loss and increase N use efficiency in the study area, it was concluded that as the age of greenhouses increased, the addition of inorganic N fertilizer should be reduced in solar greenhouse production.
2016, 24(10): 1364-1370.
doi: 10.13930/j.cnki.cjea.160496
Abstract:
Nitrogen is not only a necessary nutrient for crop growth, but also an import source of ammonia volatilization. The volatilization of ammonia occurs in the process of nitrogen fertilizer application. As an important precursor of fine particulates and a main component of atmospheric acid deposition, ammonia threatens environment health due to its volatilization caused by nitrogen fertilization. To analyze ammonia emission and distribution characteristics from nitrogen fertilizer application in 2014 of Tianjin City, we estimated ammonia emission amounts from different nitrogen fertilizer, different crops and in different areas, as well as emission factors by using emission factor method. In the ammonia emission calculation process, nitrogen fertilizer application levels of different nitrogen fertilizers used in different crops came from Statistic Yearbook, while the emission factors were derived from guidelines published by the Ministry of Environmental Protection of China, and the temperature was the annual average temperature of Tianjin City. Results showed that 17 999.91 tons of ammonia was emitted form nitrogen application in Tianjin City with the emission intensity of 3.27 t.km-2. Among five types of nitrogen fertilizer (urea, ammonium bicarbonate, ammonium nitrate, thiamine, and others), urea was the largest resource of ammonia emission, with 83.13% contribution rate, followed by ammonium bicarbonate with contribution rate of 13.83%, and the other nitrogen fertilizers was the least resource with only 3.04%. For crop types, vegetables was the largest resource of ammonia emission with 38.91% contribution rate, followed by maize with contribution rate of 29.43% and wheat with contribution rate of 19.66%, and the others occupied 12.00%. Because ammonia emissions were positively correlated with temperature, in this study, ammonia emission showed strong time-characteristics with maximum emissions in midday and August and the minimum at night and in January. In all counties/districts, Wuqing District emitted the most ammonia with contribution rate of 27.06%, while Jinnan District emitted the least with contribution rate of 1.14%. And Baodi District and Jixian District had greater contribution rate with 20.71% and 17.86%, respectively. Ammonia emission had strong spatial characteristics, and the large ammonia emission occurred mainly in farmland. To control ammonia emission from farmland in Tianjin City, the scientific application of nitrogenous fertilizer in Wuqing District, Baodi District and Jixian District in the process of vegetable cultivation in June to August should be strengthened. The results could provide a scientific basis for haze treatment in Tianjin City.
Nitrogen is not only a necessary nutrient for crop growth, but also an import source of ammonia volatilization. The volatilization of ammonia occurs in the process of nitrogen fertilizer application. As an important precursor of fine particulates and a main component of atmospheric acid deposition, ammonia threatens environment health due to its volatilization caused by nitrogen fertilization. To analyze ammonia emission and distribution characteristics from nitrogen fertilizer application in 2014 of Tianjin City, we estimated ammonia emission amounts from different nitrogen fertilizer, different crops and in different areas, as well as emission factors by using emission factor method. In the ammonia emission calculation process, nitrogen fertilizer application levels of different nitrogen fertilizers used in different crops came from Statistic Yearbook, while the emission factors were derived from guidelines published by the Ministry of Environmental Protection of China, and the temperature was the annual average temperature of Tianjin City. Results showed that 17 999.91 tons of ammonia was emitted form nitrogen application in Tianjin City with the emission intensity of 3.27 t.km-2. Among five types of nitrogen fertilizer (urea, ammonium bicarbonate, ammonium nitrate, thiamine, and others), urea was the largest resource of ammonia emission, with 83.13% contribution rate, followed by ammonium bicarbonate with contribution rate of 13.83%, and the other nitrogen fertilizers was the least resource with only 3.04%. For crop types, vegetables was the largest resource of ammonia emission with 38.91% contribution rate, followed by maize with contribution rate of 29.43% and wheat with contribution rate of 19.66%, and the others occupied 12.00%. Because ammonia emissions were positively correlated with temperature, in this study, ammonia emission showed strong time-characteristics with maximum emissions in midday and August and the minimum at night and in January. In all counties/districts, Wuqing District emitted the most ammonia with contribution rate of 27.06%, while Jinnan District emitted the least with contribution rate of 1.14%. And Baodi District and Jixian District had greater contribution rate with 20.71% and 17.86%, respectively. Ammonia emission had strong spatial characteristics, and the large ammonia emission occurred mainly in farmland. To control ammonia emission from farmland in Tianjin City, the scientific application of nitrogenous fertilizer in Wuqing District, Baodi District and Jixian District in the process of vegetable cultivation in June to August should be strengthened. The results could provide a scientific basis for haze treatment in Tianjin City.
2016, 24(10): 1371-1381.
doi: 10.13930/j.cnki.cjea.160327
Abstract:
Since the reform and opening-up was launched in 1978, environmental problems have increased due to unreasonable agricultural land use practices in China. Thus systematic analysis and evaluation of the environmental effects of agricultural land use, detailed understanding of material cycle mechanisms in agricultural systems and the improvement of material utilization efficiency have become a key research focus of land science. Substance flow analysis (SFA) is a systematic method of assessment of material flow and stock in a given system in the fabric of space and time. The SFA method is comprised of 3 parts — the sources, the pathways and the sinks. It characterizes the pathways of substances in, out and through a system and therefore an effective support tool for resources and environmental management. In this paper, an indicator system (including material input indicators, material output indicators, stock indicators, material intensity and efficiency indicators, and environmental health indicators) was established based on the SFA framework for the assessment of regional scale agricultural land use systems. The method was also used to assess material use efficiency and environmental quality in agricultural land use systems. Based on the cause-study analysis of Taojiang County (northern Hunan Province), material flow in the SFA framework in agricultural land use systems included productive input, production output, environmental output and stock. The results indicated that: (1) nitrogen derived from material productive input and environmental input sharply increased during the period from 1980 to 2013. The amounts of nitrogen derived from material productive input and environmental input in 2013 were respectively 1.2 and 0.4 times that in 1980. Productive input was the main source of nitrogen in Taojiang County. (2) Production output increased slowly during the period from 1980 to 2013. However, environmental output in 2013 approximatively doubled that in 1980. (3) There was an increasing trend in nitrogen material input intensity in Taojiang County during the period from 1980 to 2013. Material input intensity of nitrogen in 2013 was 328.4 kg?hm2, exceeding the critical value of 250.0 kg.hm-2. In addition, material use efficiency of nitrogen decreased gradually during the period. Compared with the average value for Hunan Province, material production efficiency in agricultural land use systems in Taojiang County was lowest in 2013. It was therefore important for the local government to take measures to promote the adjustment process of agricultural structure and improve added value of agricultural products in the region. (4) The stability of the ecosystem and the quality of the environment reduced gradually for the period from 1980 to 2010, however, environmental quality improved during the period during 2010 to 2013. Nitrogen load decreased from 208.8 kg.hm-2 in 2010 to 154.1 kg.hm-2 in 2013. Although to a certain extent errors existed in the SFA analysis due to data shortage and difficulties in parameterization, the SFA method was a useful tool for the evaluation of material use efficiency and environmental quality in agricultural land use systems.
Since the reform and opening-up was launched in 1978, environmental problems have increased due to unreasonable agricultural land use practices in China. Thus systematic analysis and evaluation of the environmental effects of agricultural land use, detailed understanding of material cycle mechanisms in agricultural systems and the improvement of material utilization efficiency have become a key research focus of land science. Substance flow analysis (SFA) is a systematic method of assessment of material flow and stock in a given system in the fabric of space and time. The SFA method is comprised of 3 parts — the sources, the pathways and the sinks. It characterizes the pathways of substances in, out and through a system and therefore an effective support tool for resources and environmental management. In this paper, an indicator system (including material input indicators, material output indicators, stock indicators, material intensity and efficiency indicators, and environmental health indicators) was established based on the SFA framework for the assessment of regional scale agricultural land use systems. The method was also used to assess material use efficiency and environmental quality in agricultural land use systems. Based on the cause-study analysis of Taojiang County (northern Hunan Province), material flow in the SFA framework in agricultural land use systems included productive input, production output, environmental output and stock. The results indicated that: (1) nitrogen derived from material productive input and environmental input sharply increased during the period from 1980 to 2013. The amounts of nitrogen derived from material productive input and environmental input in 2013 were respectively 1.2 and 0.4 times that in 1980. Productive input was the main source of nitrogen in Taojiang County. (2) Production output increased slowly during the period from 1980 to 2013. However, environmental output in 2013 approximatively doubled that in 1980. (3) There was an increasing trend in nitrogen material input intensity in Taojiang County during the period from 1980 to 2013. Material input intensity of nitrogen in 2013 was 328.4 kg?hm2, exceeding the critical value of 250.0 kg.hm-2. In addition, material use efficiency of nitrogen decreased gradually during the period. Compared with the average value for Hunan Province, material production efficiency in agricultural land use systems in Taojiang County was lowest in 2013. It was therefore important for the local government to take measures to promote the adjustment process of agricultural structure and improve added value of agricultural products in the region. (4) The stability of the ecosystem and the quality of the environment reduced gradually for the period from 1980 to 2010, however, environmental quality improved during the period during 2010 to 2013. Nitrogen load decreased from 208.8 kg.hm-2 in 2010 to 154.1 kg.hm-2 in 2013. Although to a certain extent errors existed in the SFA analysis due to data shortage and difficulties in parameterization, the SFA method was a useful tool for the evaluation of material use efficiency and environmental quality in agricultural land use systems.
2016, 24(10): 1382-1390.
doi: 10.13930/j.cnki.cjea.160322
Abstract:
Phytophthora blight of chili pepper, caused by oomycetes of Phytophthora capsici, has been reported to be a key limiting factor of chili pepper production worldwide. Increased public interest in protecting the environment and human health has prompted research in agronomic strategies that reduce the use of fungicides. Alternative control methods with high efficacy, low cost and limited environmental effect are high-priority research areas for sustainable agriculture. Under the same incubation conditions (soil moisture of 60% of field capacity, temperature of 25 ℃ and inoculation concentration of P. capsici of 500 CFU.g-1), DMPP (1% applied pure N) and ammonium bicarbonate (AB) [100 mg(N).kg-1] were added tofluvo-aquic soil and incubated for 15 d. Soil without any addition of DMPP and/or AB was set as the control. After incubation, DMPP or AB-treated soil was used to grow chili pepper in a pot experiment for 28 d. The effect of DMPP and AB application on disease incidence of Phytophthora blight of chili pepper was then compared. The soil physio-chemical and microbial responses (soil pH, electric conductivity, concentrations of different forms of nitrogen; numbers of total bacteria, fungi, P. capsici and ammonia-oxidizing bacteria) to the addition of DMPP and AB were determined. The relationship between Phytophthora blight disease incidence and soil phyiso-chemical and microbial characteristics was evaluated. The aim of the study was to investigate the control effects of DMPP-enhanced ammonium biocarbonate on Phytophthora blight of chili pepper and correlation with soil physio-chemical properties, and provided technological support for control of Phytophthora blight of chili pepper of greenhouse. The results suggested that compared with the control, the contents of soil ammonium nitrogen in DMPP and DMPP+AB treatments were higher, and the contents of nitrate and nitrite nitrogen significantly lower. The application of DMPP for 15 d decreased copied gene numbers of bacterial amoA and P. capsici ITS genes by 34.9% (P > 0.05) and 93.8% (P < 0.05), respectively. The copied 16S rRNA gene number increased by 54.7% (P < 0.05) compared with non-DMPP treatments. However, the copied numbers of fungal 18S rRNA gene and archaeal amoA gene were not significantly affected by DMPP. After incubation for 15 d, soil from each treatment was put into pots and ten chili pepper plants grown in each pot for 28 d. The P. capsici density was lowest in AB+DMPP (2.1×105 copies·g-1) treatment, followed by DMPP (15.4×105 copies·g-1). The control experiment had the highest number of pathogen (37.1×105 copies·g-1), which was 0.4-fold, 1.4-fold and 16.8-fold higher than those of AB, DMPP and AB+DMPP, respectively. The results from the pot experiment showed that the control treatment had the highest disease incidence (95.00%), followed by AB treatment (85.00%) and AB+DMPP treatment had the lowest disease incidence (32.20%). The efficacy of Phytophthora blight disease control by AB+DMPP treatment was 66.11%. Disease incidence was positively correlated with soil electrical conductivity, nitrate content and P. capsici population, but negatively correlated with soil pH, ammonium content and bacterial and fungal populations. The above results suggested that the control of chili pepper Phytophthora blight by the combined application of DMPP and ammonium bicarbonate decreased the number of ammonia- oxidizing bacteria, which, in turn, increased ammonium content, but also decreased soil nitrate content. Thus P. capsici population reduced under high concentration of ammonium, which effectively controlled chili pepper Phytophthora blight.
Phytophthora blight of chili pepper, caused by oomycetes of Phytophthora capsici, has been reported to be a key limiting factor of chili pepper production worldwide. Increased public interest in protecting the environment and human health has prompted research in agronomic strategies that reduce the use of fungicides. Alternative control methods with high efficacy, low cost and limited environmental effect are high-priority research areas for sustainable agriculture. Under the same incubation conditions (soil moisture of 60% of field capacity, temperature of 25 ℃ and inoculation concentration of P. capsici of 500 CFU.g-1), DMPP (1% applied pure N) and ammonium bicarbonate (AB) [100 mg(N).kg-1] were added tofluvo-aquic soil and incubated for 15 d. Soil without any addition of DMPP and/or AB was set as the control. After incubation, DMPP or AB-treated soil was used to grow chili pepper in a pot experiment for 28 d. The effect of DMPP and AB application on disease incidence of Phytophthora blight of chili pepper was then compared. The soil physio-chemical and microbial responses (soil pH, electric conductivity, concentrations of different forms of nitrogen; numbers of total bacteria, fungi, P. capsici and ammonia-oxidizing bacteria) to the addition of DMPP and AB were determined. The relationship between Phytophthora blight disease incidence and soil phyiso-chemical and microbial characteristics was evaluated. The aim of the study was to investigate the control effects of DMPP-enhanced ammonium biocarbonate on Phytophthora blight of chili pepper and correlation with soil physio-chemical properties, and provided technological support for control of Phytophthora blight of chili pepper of greenhouse. The results suggested that compared with the control, the contents of soil ammonium nitrogen in DMPP and DMPP+AB treatments were higher, and the contents of nitrate and nitrite nitrogen significantly lower. The application of DMPP for 15 d decreased copied gene numbers of bacterial amoA and P. capsici ITS genes by 34.9% (P > 0.05) and 93.8% (P < 0.05), respectively. The copied 16S rRNA gene number increased by 54.7% (P < 0.05) compared with non-DMPP treatments. However, the copied numbers of fungal 18S rRNA gene and archaeal amoA gene were not significantly affected by DMPP. After incubation for 15 d, soil from each treatment was put into pots and ten chili pepper plants grown in each pot for 28 d. The P. capsici density was lowest in AB+DMPP (2.1×105 copies·g-1) treatment, followed by DMPP (15.4×105 copies·g-1). The control experiment had the highest number of pathogen (37.1×105 copies·g-1), which was 0.4-fold, 1.4-fold and 16.8-fold higher than those of AB, DMPP and AB+DMPP, respectively. The results from the pot experiment showed that the control treatment had the highest disease incidence (95.00%), followed by AB treatment (85.00%) and AB+DMPP treatment had the lowest disease incidence (32.20%). The efficacy of Phytophthora blight disease control by AB+DMPP treatment was 66.11%. Disease incidence was positively correlated with soil electrical conductivity, nitrate content and P. capsici population, but negatively correlated with soil pH, ammonium content and bacterial and fungal populations. The above results suggested that the control of chili pepper Phytophthora blight by the combined application of DMPP and ammonium bicarbonate decreased the number of ammonia- oxidizing bacteria, which, in turn, increased ammonium content, but also decreased soil nitrate content. Thus P. capsici population reduced under high concentration of ammonium, which effectively controlled chili pepper Phytophthora blight.
2016, 24(10): 1391-1400.
doi: 10.13930/j.cnki.cjea.160386
Abstract:
High-quality late rice is preferred by most consumers for its good taste. Irrigation is an important management practice in rice cultivation. This study analyzed the effects of irrigation method on the population dynamics of Nilaparvata lugens (St?l) and the main natural enemies [ Cyrtorrhinus livdipennis (Reute), Pardosa pseudoannulata (Bose. et Str., l906)] of high-quality late rice. The study also determined the effective irrigation method which reduced the occurrence of N. lugens , that in turn reduced the use of chemical pesticides, and improved rice quality and cultivation efficiency. To do so, deficit irrigation, wet irrigation, intermittent irrigation and long-term irrigation were set up to study the effects of the various irrigation methods on the population dynamics of N. lugens and the main natural enemies of high-quality late rice under two pest control methods (biological and chemical control) and two isolation methods (semi-partitioning and full-partitioning method). The results showed that C. livdipennis occurred after N. lugens , which limited the effective control of N. lugens by C. livdipennis . The population of N. lugens under long-term irrigation was less than that under deficit irrigation and P. pseudoannulata under deficit irrigation was less than that under other irrigation methods. These differences were significant for main growth stages (booting stage to milk stage) when there was rapid growth of late rice brown plant hopper under biological control. There were significant correlations of population changes between P. pseudoannulata and C. livdipennis and N. lugens. P. pseudoannulata had an absolute control over N. lugens when N. lugens population was less than 1 891.1 per 100-clump and the ratio of N. lugens to P. pseudoannulata exceeded 9.67. Chemical pesticides had a severe lethal effect on C. livdipennis under all the irrigation methods. Long-term irrigation greatly reduced the toxicity of chemical pesticides to P. pseudoannulata . In summary, long-term irrigation was beneficial for the protection of main natural enemies of paddy rice and it was the best prevention option for N. lugens . Long-term irrigation combined production with water saving, explored the use of sub-long-term irrigation in the growth period of late rice and thereby enhanced effective water saving and reduced use of chemical pesticides.
High-quality late rice is preferred by most consumers for its good taste. Irrigation is an important management practice in rice cultivation. This study analyzed the effects of irrigation method on the population dynamics of Nilaparvata lugens (St?l) and the main natural enemies [ Cyrtorrhinus livdipennis (Reute), Pardosa pseudoannulata (Bose. et Str., l906)] of high-quality late rice. The study also determined the effective irrigation method which reduced the occurrence of N. lugens , that in turn reduced the use of chemical pesticides, and improved rice quality and cultivation efficiency. To do so, deficit irrigation, wet irrigation, intermittent irrigation and long-term irrigation were set up to study the effects of the various irrigation methods on the population dynamics of N. lugens and the main natural enemies of high-quality late rice under two pest control methods (biological and chemical control) and two isolation methods (semi-partitioning and full-partitioning method). The results showed that C. livdipennis occurred after N. lugens , which limited the effective control of N. lugens by C. livdipennis . The population of N. lugens under long-term irrigation was less than that under deficit irrigation and P. pseudoannulata under deficit irrigation was less than that under other irrigation methods. These differences were significant for main growth stages (booting stage to milk stage) when there was rapid growth of late rice brown plant hopper under biological control. There were significant correlations of population changes between P. pseudoannulata and C. livdipennis and N. lugens. P. pseudoannulata had an absolute control over N. lugens when N. lugens population was less than 1 891.1 per 100-clump and the ratio of N. lugens to P. pseudoannulata exceeded 9.67. Chemical pesticides had a severe lethal effect on C. livdipennis under all the irrigation methods. Long-term irrigation greatly reduced the toxicity of chemical pesticides to P. pseudoannulata . In summary, long-term irrigation was beneficial for the protection of main natural enemies of paddy rice and it was the best prevention option for N. lugens . Long-term irrigation combined production with water saving, explored the use of sub-long-term irrigation in the growth period of late rice and thereby enhanced effective water saving and reduced use of chemical pesticides.
2016, 24(10): 1401-1408.
doi: 10.13930/j.cnki.cjea.160355
Abstract:
To determine the cumulative effect of temperatures on the growth, development and reproduction of red pea aphid (Acyrthosiphon pisum), and further provide scientific theory for using ecological treatment on pea aphid, we studied the life tables of 3 continuous generations of red pea aphid through indoor observation under five temperature regimes (12 ℃, 17 ℃, 22 ℃, 25 ℃ and 28 ℃). Results showed that the nymph stage of F2 generation shortened by 16.0% and 6.8% compared with F0 and F1 generations at 12 ℃. There was no significant difference among three generations at 22 ℃ and 25 ℃. Respectively, F2 generation time reduced by 10.5% and 12.4% compared with F0 and F1 at 12 ℃. There was no significant difference among three filial generations at 17 ℃, 22 ℃ and 25 ℃. The average reproduction of F2 generation was significantly lower than those of F0 and F1 at 12 ℃. Also, offspring fertility obviously declined in continuous high temperature of 25 ℃. The average reproduction of F1 and F2 decreased by 49.3% and 50.9% respectively compared with F0. Also the fecundities of both F1 and F2 aphids were not significantly different compared with thatF0 at 22 ℃. Continuous feeding of red pea aphid and the related gained weight were affected by the minimum at 12 ℃ and 25 ℃ among all treatments, and there was no significant difference in weight among three generations. The weight of F1 generation was significantly higher than those of F0 and F2 generations at 22 ℃, furthermore, the body weight growth rate apparently increased with the number of generations at 12 ℃. With increasing generations, under 12 ℃ and 25 ℃, net reproductive rate (R0) and generation time (T) of red pea aphid respectively declined and shortened. The intrinsic increase rate (rmλ) of F1 and F2 generations increased significantly compared with F0 under 25 ℃. This showed that in continuous low temperature or high temperature stress, offspring fertility of red pea aphid declined. However, developmental duration shortened and with no significant changes in body weight. The intrinsic increase rate (rm) and finite increase rate (λ) increased, showing a strong adaptive capacity to the environment. This was one of the reasons for the rise of filial population of red pea aphid.
To determine the cumulative effect of temperatures on the growth, development and reproduction of red pea aphid (Acyrthosiphon pisum), and further provide scientific theory for using ecological treatment on pea aphid, we studied the life tables of 3 continuous generations of red pea aphid through indoor observation under five temperature regimes (12 ℃, 17 ℃, 22 ℃, 25 ℃ and 28 ℃). Results showed that the nymph stage of F2 generation shortened by 16.0% and 6.8% compared with F0 and F1 generations at 12 ℃. There was no significant difference among three generations at 22 ℃ and 25 ℃. Respectively, F2 generation time reduced by 10.5% and 12.4% compared with F0 and F1 at 12 ℃. There was no significant difference among three filial generations at 17 ℃, 22 ℃ and 25 ℃. The average reproduction of F2 generation was significantly lower than those of F0 and F1 at 12 ℃. Also, offspring fertility obviously declined in continuous high temperature of 25 ℃. The average reproduction of F1 and F2 decreased by 49.3% and 50.9% respectively compared with F0. Also the fecundities of both F1 and F2 aphids were not significantly different compared with thatF0 at 22 ℃. Continuous feeding of red pea aphid and the related gained weight were affected by the minimum at 12 ℃ and 25 ℃ among all treatments, and there was no significant difference in weight among three generations. The weight of F1 generation was significantly higher than those of F0 and F2 generations at 22 ℃, furthermore, the body weight growth rate apparently increased with the number of generations at 12 ℃. With increasing generations, under 12 ℃ and 25 ℃, net reproductive rate (R0) and generation time (T) of red pea aphid respectively declined and shortened. The intrinsic increase rate (rmλ) of F1 and F2 generations increased significantly compared with F0 under 25 ℃. This showed that in continuous low temperature or high temperature stress, offspring fertility of red pea aphid declined. However, developmental duration shortened and with no significant changes in body weight. The intrinsic increase rate (rm) and finite increase rate (λ) increased, showing a strong adaptive capacity to the environment. This was one of the reasons for the rise of filial population of red pea aphid.
2016, 24(10): 1409-1416.
doi: 10.13930/j.cnki.cjea.160288
Abstract:
The reproductive mode of parthenogenesis is critical for Frankliniella occidentalis (Thysanoptera: Thripidae) invasive species. Studies have shown that the survival of female thrips was significantly higher than that of male thrips at high temperature (45 ℃, 2 h). In order to explore the possibility of population establishment of western flower thrips by parthenogenesis under high temperature conditions, female adult thrips were exposed to 45 ℃ for 2 h and then their offspring (F1 generation) back-crossed with parental or “uncertain parental” female thrips. The life table was established to describe the population development of offspring after back-crossing (F2 generation). The results indicated that the above two modes of generation of female copulated with F1 male offspring both produced fertile offsprings. The sex ratio of the F2 generation from parental female adult (female︰male = 1.05︰1) was lower than the sex ratio of the F2 generation from “uncertain parental” female adults (female︰male = 1.55︰1). In addition, the F2 generation from parental female had lower average female fecundity (F, 44.25 eggs per female), lower intrinsic rate of increase (rm, 0.133 9), longer average developmental duration, longer adult pre-oviposition period (APOP, 3.13 d), longer total pre-oviposition period (TPOP, 17.19 d) and longer average generation duration (23.32 d) than the F2 generation from “uncertain parental” female adults (P < 0.05; F of 62.25 eggs per female, rm of 0.146 8, APOP of 2.85 d, TPOP of 14.45 d and longer generation duration of 20.49 d). However, no significant difference was noted in the finite rate of increase (P > 0.05). The results indicated that F. occidentalis established populations within a short time by arrhenotocous parthenogenesis and had strong resistance to high temperatures and reproductive capacity, which laid the basis for successful invasion. A single high temperature model was not ideal for the control of F. occidentalis in case of host plant without serious injuries. This suggested that multiple control modes were better. Future studies should investigate and discuss effective control modes of F. occidentalis.
The reproductive mode of parthenogenesis is critical for Frankliniella occidentalis (Thysanoptera: Thripidae) invasive species. Studies have shown that the survival of female thrips was significantly higher than that of male thrips at high temperature (45 ℃, 2 h). In order to explore the possibility of population establishment of western flower thrips by parthenogenesis under high temperature conditions, female adult thrips were exposed to 45 ℃ for 2 h and then their offspring (F1 generation) back-crossed with parental or “uncertain parental” female thrips. The life table was established to describe the population development of offspring after back-crossing (F2 generation). The results indicated that the above two modes of generation of female copulated with F1 male offspring both produced fertile offsprings. The sex ratio of the F2 generation from parental female adult (female︰male = 1.05︰1) was lower than the sex ratio of the F2 generation from “uncertain parental” female adults (female︰male = 1.55︰1). In addition, the F2 generation from parental female had lower average female fecundity (F, 44.25 eggs per female), lower intrinsic rate of increase (rm, 0.133 9), longer average developmental duration, longer adult pre-oviposition period (APOP, 3.13 d), longer total pre-oviposition period (TPOP, 17.19 d) and longer average generation duration (23.32 d) than the F2 generation from “uncertain parental” female adults (P < 0.05; F of 62.25 eggs per female, rm of 0.146 8, APOP of 2.85 d, TPOP of 14.45 d and longer generation duration of 20.49 d). However, no significant difference was noted in the finite rate of increase (P > 0.05). The results indicated that F. occidentalis established populations within a short time by arrhenotocous parthenogenesis and had strong resistance to high temperatures and reproductive capacity, which laid the basis for successful invasion. A single high temperature model was not ideal for the control of F. occidentalis in case of host plant without serious injuries. This suggested that multiple control modes were better. Future studies should investigate and discuss effective control modes of F. occidentalis.
2016, 24(10): 1417-1427.
doi: 10.13930/j.cnki.cjea.160304
Abstract:
Soil water content (SWC) is a key factor influencing crop growth in semi-arid regions. Monitoring the variations in SWC is critical for agriculture. In recent years, geophysical survey has been used in the study of high-resolution detection of water infiltration and it is hugely popular because of its zero-damage to soil micro-structure and easy measurement. With a maize field in Longzhong semi-arid region as the case study, we used high-density electrical resistivity tomography (ERT) to measure (before and after the precipitation) two-dimensional electrical resistivity of the column of soil below an electrode placed on the soil surface. Then SWC and electrical resistivity were monitored in two-dimensional soil profile in order to explain the variations in SWC under different conditions and to determine the correlation between electrical resistivity of each soil horizon and its water content in Longzhong semi-arid region. Soil temperature was also discussed in the ERT data interpretation. The results revealed the potential of ERT to improve soil and agronomic studies. Vertical distributions of two-dimensional electrical resistivity image inverted from measured data were different. On the whole, natural rainfall infiltration reduced the trend in two-dimensional electrical resistivity. The trend of local electrical resistivity of the inverted ERT images was one of “high-low-high”, quite consistent with the “dry-wet-dry” cycle of the precipitation process. Two- dimensional sections of SWC calculated using ERT showed a reliable linear correlation (R2 = 0.651 8, n = 96) between the estimated and measured SWC in the root-zone horizon, with a slope approximately equal to 1. Within the depth range of 02.0 m, the precision of the calculated specific SWC quantified by the root mean square error (RMSE) was 2.64%, with a bias corresponding to an overestimation of 0.74%. The densely distributed SWC detectors installed in the H1 horizon (00.5 m) enhanced precise data collection, resulting in better measurement accuracy than in the H2 horizon (0.52.0 m). The study also discussed the factors responsible for the deviation between measured SWC and estimated SWC. The development and adoption of precision farming and rational irrigation required detail knowledge of soil and crop. The method used in this study was useful in the research and description of high-resolution soil spatial variability and hydric characteristics. Additional field calibration was required for applying the method practical on routine field application. The use of general petro-physical relationship between soil electrical resistivity and its moisture, if appropriate, could bring the method a step closer to practical field application for the purpose of improving irrigation management.
Soil water content (SWC) is a key factor influencing crop growth in semi-arid regions. Monitoring the variations in SWC is critical for agriculture. In recent years, geophysical survey has been used in the study of high-resolution detection of water infiltration and it is hugely popular because of its zero-damage to soil micro-structure and easy measurement. With a maize field in Longzhong semi-arid region as the case study, we used high-density electrical resistivity tomography (ERT) to measure (before and after the precipitation) two-dimensional electrical resistivity of the column of soil below an electrode placed on the soil surface. Then SWC and electrical resistivity were monitored in two-dimensional soil profile in order to explain the variations in SWC under different conditions and to determine the correlation between electrical resistivity of each soil horizon and its water content in Longzhong semi-arid region. Soil temperature was also discussed in the ERT data interpretation. The results revealed the potential of ERT to improve soil and agronomic studies. Vertical distributions of two-dimensional electrical resistivity image inverted from measured data were different. On the whole, natural rainfall infiltration reduced the trend in two-dimensional electrical resistivity. The trend of local electrical resistivity of the inverted ERT images was one of “high-low-high”, quite consistent with the “dry-wet-dry” cycle of the precipitation process. Two- dimensional sections of SWC calculated using ERT showed a reliable linear correlation (R2 = 0.651 8, n = 96) between the estimated and measured SWC in the root-zone horizon, with a slope approximately equal to 1. Within the depth range of 02.0 m, the precision of the calculated specific SWC quantified by the root mean square error (RMSE) was 2.64%, with a bias corresponding to an overestimation of 0.74%. The densely distributed SWC detectors installed in the H1 horizon (00.5 m) enhanced precise data collection, resulting in better measurement accuracy than in the H2 horizon (0.52.0 m). The study also discussed the factors responsible for the deviation between measured SWC and estimated SWC. The development and adoption of precision farming and rational irrigation required detail knowledge of soil and crop. The method used in this study was useful in the research and description of high-resolution soil spatial variability and hydric characteristics. Additional field calibration was required for applying the method practical on routine field application. The use of general petro-physical relationship between soil electrical resistivity and its moisture, if appropriate, could bring the method a step closer to practical field application for the purpose of improving irrigation management.
2016, 24(10): 1428-1434.
doi: 10.13930/j.cnki.cjea.160017
Abstract:
Although water resources is the basis of food security, agricultural water shortage is rampant in China. In view of regional differences in agricultural water use in the country, 10 indicators were selected and adopted for zoning of agricultural water consumption. Ten indicators belong to four groups (the conditions of water resources, the level of economic development, the state of agricultural production, and the features of agricultural water use) were selected, and cluster analysis used to divide agricultural water consumption zones with 2013 as the base year. The results indicated that China was divided in 8 zones of agricultural water consumption based on administrative units at provincial level. The first zone included Jiangxi, Hunan and Hubei Provinces, where the proportions of total agricultural water use (TAWU) and grain production in the country were 13.3% and 12.5%, respectively. The second zone included Guizhou, Yunnan, Anhui, Sichuan, Chongqing and Guangxi Provinces (City or Autonomous Region), where TAWU and grain production were 23.6% and 20.3%, respectively. The third zone covered Hainan Province for which the TAWU and grain production were 0.9% and 0.3%, respectively. Then the forth zone included Shandong, Henan, Hebei, Liaoning, Shanxi, Shaanxi and Gansu Provinces with a combined agricultural output accounting for 33.7% of the total agricultural output of the country and accounted for 32.4% of the China’s total grain production. However, it had only 6.8% of the total amount of water and used only 19.2% water resources of the country. The fifth zone included Jilin, Heilongjiang and Inner Mongolia Provinces (Autonomous Region), accounting for 20.5% of the country’s total grain production, 6.9% of its total water amount and 12.0% of the TAWU. The sixth zone covered Ningxia, Xinjiang, Tibet and Qinghai, accounting respectively for 16.2% and 3.2% of the country’s TAWU and grain production. The seventh zone included Fujian, Guangdong, Jiangsu and Zhejiang Provinces, with 19.5% and 10.2% of China’s TAWU and grain production, respectively. The eighth zone included Tianjin, Shanghai, Beijing, etc., which accounted for 1.1% and 0.6% of the China’s TAWU and grain production, respectively. As the agricultural water use and grain production in the fourth and fifth zones accounted respectively for 31.2% and 52.9% of the country’s total, there was need to treat the two zones with a specific concern in terms of agricultural water management. Among the countermeasures to agricultural water use put forward for the zones, water saving was important for the first zone, improved irrigation water use coefficient for the second zone, increased effective irrigation area in the third zone, and improved total water resources through water transfer from other basins and increased water-saving potential inside the basins for forth zone. There was the need to increase the degree of water assurance in the fifth zone, to focus on water resources protection and conservation in the sixth zone, and to promote water utilization efficiency in the seventh and eighth zones. The paper therefore solidly laid the scientific basis for sustainable utilization of water resources in the whole of China.
Although water resources is the basis of food security, agricultural water shortage is rampant in China. In view of regional differences in agricultural water use in the country, 10 indicators were selected and adopted for zoning of agricultural water consumption. Ten indicators belong to four groups (the conditions of water resources, the level of economic development, the state of agricultural production, and the features of agricultural water use) were selected, and cluster analysis used to divide agricultural water consumption zones with 2013 as the base year. The results indicated that China was divided in 8 zones of agricultural water consumption based on administrative units at provincial level. The first zone included Jiangxi, Hunan and Hubei Provinces, where the proportions of total agricultural water use (TAWU) and grain production in the country were 13.3% and 12.5%, respectively. The second zone included Guizhou, Yunnan, Anhui, Sichuan, Chongqing and Guangxi Provinces (City or Autonomous Region), where TAWU and grain production were 23.6% and 20.3%, respectively. The third zone covered Hainan Province for which the TAWU and grain production were 0.9% and 0.3%, respectively. Then the forth zone included Shandong, Henan, Hebei, Liaoning, Shanxi, Shaanxi and Gansu Provinces with a combined agricultural output accounting for 33.7% of the total agricultural output of the country and accounted for 32.4% of the China’s total grain production. However, it had only 6.8% of the total amount of water and used only 19.2% water resources of the country. The fifth zone included Jilin, Heilongjiang and Inner Mongolia Provinces (Autonomous Region), accounting for 20.5% of the country’s total grain production, 6.9% of its total water amount and 12.0% of the TAWU. The sixth zone covered Ningxia, Xinjiang, Tibet and Qinghai, accounting respectively for 16.2% and 3.2% of the country’s TAWU and grain production. The seventh zone included Fujian, Guangdong, Jiangsu and Zhejiang Provinces, with 19.5% and 10.2% of China’s TAWU and grain production, respectively. The eighth zone included Tianjin, Shanghai, Beijing, etc., which accounted for 1.1% and 0.6% of the China’s TAWU and grain production, respectively. As the agricultural water use and grain production in the fourth and fifth zones accounted respectively for 31.2% and 52.9% of the country’s total, there was need to treat the two zones with a specific concern in terms of agricultural water management. Among the countermeasures to agricultural water use put forward for the zones, water saving was important for the first zone, improved irrigation water use coefficient for the second zone, increased effective irrigation area in the third zone, and improved total water resources through water transfer from other basins and increased water-saving potential inside the basins for forth zone. There was the need to increase the degree of water assurance in the fifth zone, to focus on water resources protection and conservation in the sixth zone, and to promote water utilization efficiency in the seventh and eighth zones. The paper therefore solidly laid the scientific basis for sustainable utilization of water resources in the whole of China.
Editor-in-chief：LIU Changming
Competent Authorities：Chinese Academy of Sciences
Sponsored by：Institute of Genetics and Developmental Biology, Chinese Academy of Sciences; China Ecological Economics Society
Organizer：Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
ISSN 2096-6237
CN 13-1432/S
- Chinese core periodicals
- Core Chinese Sci-Tech Periodicals
- China's Top Science and Technology Periodicals
- Covered by Chinese Science Citation Database (CSCD)
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