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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. 2
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2016, 24(2): 131-141.
doi: 10.13930/j.cnki.cjea.150904
Abstract:
To determine reasonable nitrogen (N) application amount and seedling density of wheat for improving N utilization efficiency and yield, N contents in organs in different parts of wheat plant were measured, and wheat response to N application (in terms of N accumulation and translocation) and planting density was studied. In the field experiment, ‘Zhoumai 22’ wheat cultivar was used in a split-plot design with N fertilization amount as the main plot and seedling density as the secondary plot. Nitrogen fertilization amounts during the whole growth period were 0 kghm-2 (N0), 120 kghm-2 (N1), 240 kghm-2 (N2) and 360 kghm-2 (N3), respectively, while seedling densities were 225×104 seedlingshm-2 (M1), 375×104 seedlingshm-2 (M2) and 525×104 seedlingshm-2 (M3), respectively. The results showed that N application amounts, seedling densities and the interactions of the two factors had significant effects on N contents in organs in different positions of aboveground wheat at anthesis and maturity stages. N content and accumulation in the vegetative organs of wheat at maturity declined compared with those at anthesis. Total N accumulation in individual plant was changed within range of 7.2759.65 mgstem1 at anthesis and 8.4860.83 mgstem1 at maturity, and the maximum data was observed in N3M2 treatment, while the minimum level was observed in N3M2 treatment. N content and accumulation in vegetative organs of wheat apparently decreased with decreasing of spatial position at anthesis stage. Also N transport and contribution rate of vegetative parts to grain had the same spatial distribution trend. It suggested that flag-leaf and the first upper internode were higher while the fourth upper leaf and the fourth upper internode as well as the other bottom parts near the ground were apparently lower. N content, accumulation and transport capacity of vegetative organs increased with increasing N application rate. N transport rate in the organs of upper and middle spatial position exceeded 50%, and total N contribution rate of vegetative organs to grain exceeded 67%. Increased N fertilizer amount combined with suitable planting density improved the capacity of N accumulation and translocation in aboveground system. Among all the vegetative organs, the ones nearest the ground (such as the fourth upper leaf and internode) were more obviously affected by N application and seedling density while N content and accumulation in those parts were significantly higher under higher N application and medium-level density, narrowing the differences with upper parts of the plant. Also N transport of plant population (28.56549.49 kghm-2) increased with increasing N application amount, especially for plant spike and internode. Grain yield, grain protein content and protein yield were significantly influenced by N application rate. While grain protein content and protein yield were significantly driven by applied N amount and N amount/seedling density interactions, protein yield was driven by seedling density. Considering N transport and grain yield, N application at 240 kghm-2 and seedling density at 225 × 104 planthm-2 were suitable for ‘Zhoumai 22’ in wheat/corn double cropping in Huanghuai region.
To determine reasonable nitrogen (N) application amount and seedling density of wheat for improving N utilization efficiency and yield, N contents in organs in different parts of wheat plant were measured, and wheat response to N application (in terms of N accumulation and translocation) and planting density was studied. In the field experiment, ‘Zhoumai 22’ wheat cultivar was used in a split-plot design with N fertilization amount as the main plot and seedling density as the secondary plot. Nitrogen fertilization amounts during the whole growth period were 0 kghm-2 (N0), 120 kghm-2 (N1), 240 kghm-2 (N2) and 360 kghm-2 (N3), respectively, while seedling densities were 225×104 seedlingshm-2 (M1), 375×104 seedlingshm-2 (M2) and 525×104 seedlingshm-2 (M3), respectively. The results showed that N application amounts, seedling densities and the interactions of the two factors had significant effects on N contents in organs in different positions of aboveground wheat at anthesis and maturity stages. N content and accumulation in the vegetative organs of wheat at maturity declined compared with those at anthesis. Total N accumulation in individual plant was changed within range of 7.2759.65 mgstem1 at anthesis and 8.4860.83 mgstem1 at maturity, and the maximum data was observed in N3M2 treatment, while the minimum level was observed in N3M2 treatment. N content and accumulation in vegetative organs of wheat apparently decreased with decreasing of spatial position at anthesis stage. Also N transport and contribution rate of vegetative parts to grain had the same spatial distribution trend. It suggested that flag-leaf and the first upper internode were higher while the fourth upper leaf and the fourth upper internode as well as the other bottom parts near the ground were apparently lower. N content, accumulation and transport capacity of vegetative organs increased with increasing N application rate. N transport rate in the organs of upper and middle spatial position exceeded 50%, and total N contribution rate of vegetative organs to grain exceeded 67%. Increased N fertilizer amount combined with suitable planting density improved the capacity of N accumulation and translocation in aboveground system. Among all the vegetative organs, the ones nearest the ground (such as the fourth upper leaf and internode) were more obviously affected by N application and seedling density while N content and accumulation in those parts were significantly higher under higher N application and medium-level density, narrowing the differences with upper parts of the plant. Also N transport of plant population (28.56549.49 kghm-2) increased with increasing N application amount, especially for plant spike and internode. Grain yield, grain protein content and protein yield were significantly influenced by N application rate. While grain protein content and protein yield were significantly driven by applied N amount and N amount/seedling density interactions, protein yield was driven by seedling density. Considering N transport and grain yield, N application at 240 kghm-2 and seedling density at 225 × 104 planthm-2 were suitable for ‘Zhoumai 22’ in wheat/corn double cropping in Huanghuai region.
2016, 24(2): 142-153.
Abstract:
This study was set up to determine the effect of fertilization depth on maize (Zea mays L.) productivity, root growth and rhizosphere soil fertility in immature loess subsoil. To that end, a sample of immature loess subsoil was analyzed for the effect of different fertilization depths (020 cm, 6080 cm, 100120 cm, 140160 cm and 180200 cm) of bio-organic fertilizer on maize productivity and the vertical distribution of root weight, rhizospheric soil enzyme activity and rhizosphere soil nutrients in a 2-year root-tube soil column culture. The control treatment (CK) was not treated with fertilizer. The results showed that: 1) indicators such as maize productivity, total root weight, etc., increased at the start and then decreased with increasing fertilization depth from 0 cm to 200 cm. The largest root weight (52.3 g) and productivity (361.0 g) of maize were obtained under the 100120 cm fertilization depth. 2) In all the treatments, the vertical distribution of maize root weight followed a T-shape and the largest maize root weight was noted in the 020 cm soil layer, which accounted for up about 50% of the total root weight. Root weight significantly declined with increasing soil depth (P < 0.05). Under 100120 cm fertilization depth treatment, both total root weight and root weight of 040 cm soil layer (27.19 g) reached the highest level, furthermore, N, P and K accumulation in the root were moderate with 6.60 gkg1, 2.38 gkg-1 and 8.16 gkg-1, respectively. 3) Fertilization significantly increased enzymes activities and nutrients contents in rhizospheric soil. Urease activity in 0 200 cm rhizospheric soil increased [0.1080.354 mg(NH3-N)g-1(soil)24h-1] in the 6080 cm fertilization depth treatment. In the 140160 cm fertilization depth treatment, sucrase activity and available phosphorus content of 0200 cm rhizospheric soil increased to 12.919.6 mg(glucose)g-1(soil)24h-1 and 4.316.02 mgkg-1, respectively. Maize rhizosphere soil organic matter content was higher (5.557.14 gkg-1) in the 180200 cm fertilization depth treatment. When fertilization depth was less than 100 cm or deeper than 120 cm, maize rhizospheric soil alkline phosphatase activity and available nitrogen content kept higher level, which were more than 0.497 mg(phenol)g1(soil)24h-1 and 25.4 mgkg-1, respectively. 4) Significant correlations among root weight, root NPK nutrient, three rhizospheric soil enzyme activities and three rhizospheric soil nutrients under different fertilization depth treatments were observed in the immature loess subsoil. 5) The optimized fertilization depth was 60160 cm for improving maize shoot-root-soil systems in the immature loess subsoil based on FACTOR and CLUSTER analyses. This study provided a new idea for speeding up the raw soil maturation process through changing fertilizers application depth.
This study was set up to determine the effect of fertilization depth on maize (Zea mays L.) productivity, root growth and rhizosphere soil fertility in immature loess subsoil. To that end, a sample of immature loess subsoil was analyzed for the effect of different fertilization depths (020 cm, 6080 cm, 100120 cm, 140160 cm and 180200 cm) of bio-organic fertilizer on maize productivity and the vertical distribution of root weight, rhizospheric soil enzyme activity and rhizosphere soil nutrients in a 2-year root-tube soil column culture. The control treatment (CK) was not treated with fertilizer. The results showed that: 1) indicators such as maize productivity, total root weight, etc., increased at the start and then decreased with increasing fertilization depth from 0 cm to 200 cm. The largest root weight (52.3 g) and productivity (361.0 g) of maize were obtained under the 100120 cm fertilization depth. 2) In all the treatments, the vertical distribution of maize root weight followed a T-shape and the largest maize root weight was noted in the 020 cm soil layer, which accounted for up about 50% of the total root weight. Root weight significantly declined with increasing soil depth (P < 0.05). Under 100120 cm fertilization depth treatment, both total root weight and root weight of 040 cm soil layer (27.19 g) reached the highest level, furthermore, N, P and K accumulation in the root were moderate with 6.60 gkg1, 2.38 gkg-1 and 8.16 gkg-1, respectively. 3) Fertilization significantly increased enzymes activities and nutrients contents in rhizospheric soil. Urease activity in 0 200 cm rhizospheric soil increased [0.1080.354 mg(NH3-N)g-1(soil)24h-1] in the 6080 cm fertilization depth treatment. In the 140160 cm fertilization depth treatment, sucrase activity and available phosphorus content of 0200 cm rhizospheric soil increased to 12.919.6 mg(glucose)g-1(soil)24h-1 and 4.316.02 mgkg-1, respectively. Maize rhizosphere soil organic matter content was higher (5.557.14 gkg-1) in the 180200 cm fertilization depth treatment. When fertilization depth was less than 100 cm or deeper than 120 cm, maize rhizospheric soil alkline phosphatase activity and available nitrogen content kept higher level, which were more than 0.497 mg(phenol)g1(soil)24h-1 and 25.4 mgkg-1, respectively. 4) Significant correlations among root weight, root NPK nutrient, three rhizospheric soil enzyme activities and three rhizospheric soil nutrients under different fertilization depth treatments were observed in the immature loess subsoil. 5) The optimized fertilization depth was 60160 cm for improving maize shoot-root-soil systems in the immature loess subsoil based on FACTOR and CLUSTER analyses. This study provided a new idea for speeding up the raw soil maturation process through changing fertilizers application depth.
2016, 24(2): 154-162.
Abstract:
With a cropping area of 1.76 million hectares, the grey desert soil (hapliccalcisol) is crucial for agricultural development in Xinjiang, Northwest China. The use of chemical and manure fertilizers has been an effective way of increasing crop production. However, there has been limited information on crop yield and soil organic carbon evolution in the region under long-term fertilization using both organic and inorganic fertilizers. Thus this study was conducted to determine the relationship among carbon input, soil organic carbon and crop yield in grey desert soil in Modern Agricultural S&T Demonstration Garden of Xinjiang Academy of Agricultural Sciences. The study also analyzed the trends in variations in crop yield and soil organic carbon under different long-term fertilization practices. The results of the study will provide scientific database which can be used to improve soil fertility and promote sustainable development of crop production in the study area. A long-term experiment was conducted using various fertilizations in 1990–2013 in wheat (Triticum aestivium) and maize (Zea mays) crop rotation system in grey desert soil. The fertilization treatments included the control without fertilization (CK), chemical nitrogen plus phosphate fertilization (NP), chemical nitrogen plus phosphate and potassium fertilization (NPK), NPK plus animal manure (NPKM), two times animal manure of NPKM (hNPKM), and NPK plus straw (NPKS). The results showed that: 1) soil organic carbon contents of CK, NP and NPK decreased by 0.094 g·kg-1·a-1, 0.043 g·kg-1·a-1 and 0.053 g·kg-1·a-1, respectively, from 1990 to 2013. Although chemical fertilization increased crop production, but decreased soil fertility. Annual rates of soil organic carbon increase under NPKM and hNPKM treatments were 0.360 g·kg-1 and 0.575 g·kg-1, respectively, from 1990 to 2013. Therefore the application of manure played an important role in improvement of soil fertility for crop cultivation. 2) Compared with CK, long-term application of chemical fertilizers with manure (NPKM and hNPKM) increased crop yield. However, compared with NP and NPK treatments, chemical fertilizers with manure (NPKM and hNPKM) significantly increased wheat yield (P < 0.05). There was, however, no significant difference in maize yield between observed manure treatments and chemical fertilizers treatments (P > 0.05). The highest maize yield was 220 kg·hm-2·a-1 under NPK treatment. The coefficient of variation of wheat yield (29.1%–43.9%) was higher than that of maize yield (19.0%–32.7%). There were no differences between NPK with straw and NPK with manure, which suggesting that the effects of straw return on crop yield was not negligible. 3) Carbon input was significantly positively correlated with soil organic carbon and crop yield (P < 0.05). Thus increasing carbon input (manure or straw return) was a key of improving soil fertility in the grey desert soil region.
With a cropping area of 1.76 million hectares, the grey desert soil (hapliccalcisol) is crucial for agricultural development in Xinjiang, Northwest China. The use of chemical and manure fertilizers has been an effective way of increasing crop production. However, there has been limited information on crop yield and soil organic carbon evolution in the region under long-term fertilization using both organic and inorganic fertilizers. Thus this study was conducted to determine the relationship among carbon input, soil organic carbon and crop yield in grey desert soil in Modern Agricultural S&T Demonstration Garden of Xinjiang Academy of Agricultural Sciences. The study also analyzed the trends in variations in crop yield and soil organic carbon under different long-term fertilization practices. The results of the study will provide scientific database which can be used to improve soil fertility and promote sustainable development of crop production in the study area. A long-term experiment was conducted using various fertilizations in 1990–2013 in wheat (Triticum aestivium) and maize (Zea mays) crop rotation system in grey desert soil. The fertilization treatments included the control without fertilization (CK), chemical nitrogen plus phosphate fertilization (NP), chemical nitrogen plus phosphate and potassium fertilization (NPK), NPK plus animal manure (NPKM), two times animal manure of NPKM (hNPKM), and NPK plus straw (NPKS). The results showed that: 1) soil organic carbon contents of CK, NP and NPK decreased by 0.094 g·kg-1·a-1, 0.043 g·kg-1·a-1 and 0.053 g·kg-1·a-1, respectively, from 1990 to 2013. Although chemical fertilization increased crop production, but decreased soil fertility. Annual rates of soil organic carbon increase under NPKM and hNPKM treatments were 0.360 g·kg-1 and 0.575 g·kg-1, respectively, from 1990 to 2013. Therefore the application of manure played an important role in improvement of soil fertility for crop cultivation. 2) Compared with CK, long-term application of chemical fertilizers with manure (NPKM and hNPKM) increased crop yield. However, compared with NP and NPK treatments, chemical fertilizers with manure (NPKM and hNPKM) significantly increased wheat yield (P < 0.05). There was, however, no significant difference in maize yield between observed manure treatments and chemical fertilizers treatments (P > 0.05). The highest maize yield was 220 kg·hm-2·a-1 under NPK treatment. The coefficient of variation of wheat yield (29.1%–43.9%) was higher than that of maize yield (19.0%–32.7%). There were no differences between NPK with straw and NPK with manure, which suggesting that the effects of straw return on crop yield was not negligible. 3) Carbon input was significantly positively correlated with soil organic carbon and crop yield (P < 0.05). Thus increasing carbon input (manure or straw return) was a key of improving soil fertility in the grey desert soil region.
2016, 24(2): 163-172.
Abstract:
The application of dredged sludge in agricultural soils has become a promising disposal and utilization method of sludge that improves soil properties and enhances plant productivity. A field experiment of rice (‘Wuyunjing 24’) cultivation was conducted in 2013 and 2014 with application of 20 kgm-2 dredged sludge from a polluted river in Xiangcheng District, Suzhou City. In the field research, two levels of nitrogen (N) application [LN, 120 kg(N)hm-2; NN, 240 kg(N)hm-2] were arranged to determine the effects of application of dredged sludge on physicochemical properties of soil, rice yield, heavy metals contents of rice grain and soil, and nitrogen use efficiency under different N application levels. The results showed that: 1) compared with no dredged sludge application (CK) treatment, field application of dredged sludge significantly increased soil organic matter and available nitrogen contents in paddy field at different growth stages of rice. Dredged sludge application significantly increased the contents of heavy metals (Cu, Zn, Pb) in soil, while it fell below the controlled plant standards for agricultural use. Field application of dredged sludge significantly increased rice yield by 7.05% (P < 0.01), the contents of Cu, Zn and Pb in rice grain by an average of 53.66% (P < 0.01), 18.71% (P < 0.01) and 802.29% (P < 0.01), respectively. Dredged sludge application improved nitrogen accumulation in rice, but reduced N use efficiency of rice biomass (NUEp) and N use efficiency of rice grain (NUEg). 2) High nitrogen supply increased soil organic matter, available nitrogen, rice yield and rice nitrogen accumulation under application of dredged sludge, but had no effect on the contents of heavy metals in soil and rice grain, while NUEp and NUEg showed the reverse trends. 3) The contents of heavy metals in the soil under dredged sludge treatment decreased by 5.0%, and in rice grain decreased by 7.27%12.65% in the second experimental season compared with that of the first experimental season. However, the contents of heavy metals in soil under dredged sludge treatment were still higher than that under CK treatment. 4) Most of the interactions between dredged sludge & N, dredged sludge & time, N & time, and dredged sludge & N & time had no significant effect on the contents of soil nutrients and heavy metals, rice yield, heavy metals in rice grain, and on nitrogen accumulation and nitrogen use efficiency of rice. It was therefore concluded that field application of dredged sludge increased soil nutrient, rice yield and heavy metals contents in rice grain and soil. However, nitrogen use efficiency showed the reverse trend.
The application of dredged sludge in agricultural soils has become a promising disposal and utilization method of sludge that improves soil properties and enhances plant productivity. A field experiment of rice (‘Wuyunjing 24’) cultivation was conducted in 2013 and 2014 with application of 20 kgm-2 dredged sludge from a polluted river in Xiangcheng District, Suzhou City. In the field research, two levels of nitrogen (N) application [LN, 120 kg(N)hm-2; NN, 240 kg(N)hm-2] were arranged to determine the effects of application of dredged sludge on physicochemical properties of soil, rice yield, heavy metals contents of rice grain and soil, and nitrogen use efficiency under different N application levels. The results showed that: 1) compared with no dredged sludge application (CK) treatment, field application of dredged sludge significantly increased soil organic matter and available nitrogen contents in paddy field at different growth stages of rice. Dredged sludge application significantly increased the contents of heavy metals (Cu, Zn, Pb) in soil, while it fell below the controlled plant standards for agricultural use. Field application of dredged sludge significantly increased rice yield by 7.05% (P < 0.01), the contents of Cu, Zn and Pb in rice grain by an average of 53.66% (P < 0.01), 18.71% (P < 0.01) and 802.29% (P < 0.01), respectively. Dredged sludge application improved nitrogen accumulation in rice, but reduced N use efficiency of rice biomass (NUEp) and N use efficiency of rice grain (NUEg). 2) High nitrogen supply increased soil organic matter, available nitrogen, rice yield and rice nitrogen accumulation under application of dredged sludge, but had no effect on the contents of heavy metals in soil and rice grain, while NUEp and NUEg showed the reverse trends. 3) The contents of heavy metals in the soil under dredged sludge treatment decreased by 5.0%, and in rice grain decreased by 7.27%12.65% in the second experimental season compared with that of the first experimental season. However, the contents of heavy metals in soil under dredged sludge treatment were still higher than that under CK treatment. 4) Most of the interactions between dredged sludge & N, dredged sludge & time, N & time, and dredged sludge & N & time had no significant effect on the contents of soil nutrients and heavy metals, rice yield, heavy metals in rice grain, and on nitrogen accumulation and nitrogen use efficiency of rice. It was therefore concluded that field application of dredged sludge increased soil nutrient, rice yield and heavy metals contents in rice grain and soil. However, nitrogen use efficiency showed the reverse trend.
2016, 24(2): 173-182.
Abstract:
It is important to get high maize yield by increasing planting density, but this could have some shortfalls (e.g., canopy closure) which limit further increase in planting density. In order to alleviate canopy closure of summer maize under high density and to improve population quality and yield, a 2-year field experiment was conducted at the Wuqiao Experimental Station of China Agricultural University. Three treatments were designed in the field, including one plant per hill (P1), two plants per hill (P2), and three plants per hill (P3) under planting density of 82 500 plant·hm2. Then the study estimated leaf area per plant, dry matter (DM), photosynthetic potential (PP), relative growth rate (RGR), net assimilation rate (NAR), crop growth rate (CGR), grain-leaf area ratio and grain yield. Leaf areas under P2 and P3 treatments at silking stage (R1) increased by 10.7%21.9% and 7.3%16.7%, respectively. At about 20 days after silking (DAS), leaf areas under P2 and P3 treatments increased by 13.5%21.9% and 9.4%12.7%, respectively, compared with P1 treatment. The DM of P2 and P3 treatments at R1 and physiological maturity stage (M) was significantly higher (P < 0.05) than that of P1 treatment. PP was improved at 6-leaf stage under P2 treatment, but decreased with increasing number of plants per hill. Compared with P1 treatment, RGR from DAS20 to M increased by 30.4%190.7% and 33.9%183.5%, NAR increased by 16.1%161.9% and 30.7%155.8%, respectively, under P2 and P3 treatments. Also CGR, grain-leaf area ratio and grain yield were enhanced under P2 and P3 treatments. Compared with P1 treatment, yield under P2 and P3 treatments increased by 5.8%23.5% and 4.9%18.9%, respectively. It was noted that ear number per hectare and grain number per ear under P2 treatment slightly increased and the thousand-grain weight increased obviously over that of P1 treatment. Analysis of ear number per hectare, grain number per ear and thousand-grain weight after two years of growth showed that ear number per hectare dropped slightly, grain number per ear increased slightly, and thousand-grain weight evidently increased under P3 treatment, compared with P1 treatment. Yield showed significant and positive linear correlation with grain weight/leaf area ratio (R2 = 0.94****) and grain number/leaf area ratio (R2 = 0.76***). Thus under high density conditions, more plants per hill improved the processes of leaf area and dry matter accumulation that in turn improved population quality. The increment in grain yield under more plants per hill was mainly due to the enhancements of thousand-grain weight and grain number per ear. In conclusion, population quality, yield and yield components were improved in two plants per hill treatment. Thus based on this study, two plants per hill planting pattern was recommended as the best performing planting pattern of maize.
It is important to get high maize yield by increasing planting density, but this could have some shortfalls (e.g., canopy closure) which limit further increase in planting density. In order to alleviate canopy closure of summer maize under high density and to improve population quality and yield, a 2-year field experiment was conducted at the Wuqiao Experimental Station of China Agricultural University. Three treatments were designed in the field, including one plant per hill (P1), two plants per hill (P2), and three plants per hill (P3) under planting density of 82 500 plant·hm2. Then the study estimated leaf area per plant, dry matter (DM), photosynthetic potential (PP), relative growth rate (RGR), net assimilation rate (NAR), crop growth rate (CGR), grain-leaf area ratio and grain yield. Leaf areas under P2 and P3 treatments at silking stage (R1) increased by 10.7%21.9% and 7.3%16.7%, respectively. At about 20 days after silking (DAS), leaf areas under P2 and P3 treatments increased by 13.5%21.9% and 9.4%12.7%, respectively, compared with P1 treatment. The DM of P2 and P3 treatments at R1 and physiological maturity stage (M) was significantly higher (P < 0.05) than that of P1 treatment. PP was improved at 6-leaf stage under P2 treatment, but decreased with increasing number of plants per hill. Compared with P1 treatment, RGR from DAS20 to M increased by 30.4%190.7% and 33.9%183.5%, NAR increased by 16.1%161.9% and 30.7%155.8%, respectively, under P2 and P3 treatments. Also CGR, grain-leaf area ratio and grain yield were enhanced under P2 and P3 treatments. Compared with P1 treatment, yield under P2 and P3 treatments increased by 5.8%23.5% and 4.9%18.9%, respectively. It was noted that ear number per hectare and grain number per ear under P2 treatment slightly increased and the thousand-grain weight increased obviously over that of P1 treatment. Analysis of ear number per hectare, grain number per ear and thousand-grain weight after two years of growth showed that ear number per hectare dropped slightly, grain number per ear increased slightly, and thousand-grain weight evidently increased under P3 treatment, compared with P1 treatment. Yield showed significant and positive linear correlation with grain weight/leaf area ratio (R2 = 0.94****) and grain number/leaf area ratio (R2 = 0.76***). Thus under high density conditions, more plants per hill improved the processes of leaf area and dry matter accumulation that in turn improved population quality. The increment in grain yield under more plants per hill was mainly due to the enhancements of thousand-grain weight and grain number per ear. In conclusion, population quality, yield and yield components were improved in two plants per hill treatment. Thus based on this study, two plants per hill planting pattern was recommended as the best performing planting pattern of maize.
2016, 24(2): 183-191.
Abstract:
Aiming at competition for land and light between forestry and agriculture, a jujube (Ziziphus jujuba Mill.) and wheat (Triticum aestivum L.) strip intercropping system in north-south direction with 3 m × 4 m plant and row spacing was used to study light distribution of winter wheat canopy. In the field, two treatments of jujube and winter wheat intercropping (JZ) and monocrop of winter wheat (CK) were investigated during the 2013–2014 growing season. In winter wheat trip, measurement points were set at every 50 cm distance between two jujube trees (reference spacing). Thus seven measurement points were subsequently set as E50 cm, E100 cm and E150 cm, E200 cm (W200 cm) and W150 cm, W100 cm and W50 cm (E and W meant the eastern and western parts of winter wheat trip). In the monocultured winter wheat system, the same measurement pointes were set also. During different growth stages of winter wheat (tillering, jointing, heading, flowering, filling and mature stages), the photosynthetically active radiation (PAR) of winter wheat canopy in different positions was measured. At maturity, the yield of winter wheat was also investigated. The spatial windows of canopy saturated PAR of winter wheat at different growth stages were analyzed using polynomial regression and fixed interval integral so as to determine light distribution of winter wheat canopy in jujube-wheat strip intercropping system. The results showed that under strip intercropping system, canopy light intensity and yield of winter wheat had different spatial and temporal distribution characteristics. There was a certain degree of attenuation compared to winter wheat monocrop system. The space-time windows of canopy saturated PAR, grain number per spike, effective panicle number, 1000-grain weight, yield under monocrop of winter wheat (the control) were respectively 56.1%, 14.7%, 15.9%, 33.5% and 53.0% higher than those under intercropping system. Compared with monocultured winter wheat (control) the space-time windows of canopy saturated PAR of intercropped winter wheat system at E50E100 cm, E100E150 cm and E150E200 cm, and W150W200 cm, W100W150 cm and W50W100 cm suffered serious losses of 92.5%, 45.7% and 7.0%, and 5.4%, 10.9% and 54.0%, respectively. The losses of space-time windows of canopy saturated PAR resulted in a decrease in winter wheat yield, respectively, by 46.2%, 39.6% and 26.3%, 24.7%, 32.4% and 37.6%. The results of the study suggested that the differences in the degree of shading of jujube plants were the causes of the differences in yield reductions of winter wheat. The lighting quality in the west side of winter wheat strip in intercropping system was better than that in the east side during the whole growth period. As a result, jujube could be properly trimmed after winter wheat flowering and the east spacing appropriately increased, not only to control the over growth of new jujube branches, but also to improve winter wheat canopy PAR interception. This could ensure high yield of winter wheat under intercropping system of jujube and winter wheat.
Aiming at competition for land and light between forestry and agriculture, a jujube (Ziziphus jujuba Mill.) and wheat (Triticum aestivum L.) strip intercropping system in north-south direction with 3 m × 4 m plant and row spacing was used to study light distribution of winter wheat canopy. In the field, two treatments of jujube and winter wheat intercropping (JZ) and monocrop of winter wheat (CK) were investigated during the 2013–2014 growing season. In winter wheat trip, measurement points were set at every 50 cm distance between two jujube trees (reference spacing). Thus seven measurement points were subsequently set as E50 cm, E100 cm and E150 cm, E200 cm (W200 cm) and W150 cm, W100 cm and W50 cm (E and W meant the eastern and western parts of winter wheat trip). In the monocultured winter wheat system, the same measurement pointes were set also. During different growth stages of winter wheat (tillering, jointing, heading, flowering, filling and mature stages), the photosynthetically active radiation (PAR) of winter wheat canopy in different positions was measured. At maturity, the yield of winter wheat was also investigated. The spatial windows of canopy saturated PAR of winter wheat at different growth stages were analyzed using polynomial regression and fixed interval integral so as to determine light distribution of winter wheat canopy in jujube-wheat strip intercropping system. The results showed that under strip intercropping system, canopy light intensity and yield of winter wheat had different spatial and temporal distribution characteristics. There was a certain degree of attenuation compared to winter wheat monocrop system. The space-time windows of canopy saturated PAR, grain number per spike, effective panicle number, 1000-grain weight, yield under monocrop of winter wheat (the control) were respectively 56.1%, 14.7%, 15.9%, 33.5% and 53.0% higher than those under intercropping system. Compared with monocultured winter wheat (control) the space-time windows of canopy saturated PAR of intercropped winter wheat system at E50E100 cm, E100E150 cm and E150E200 cm, and W150W200 cm, W100W150 cm and W50W100 cm suffered serious losses of 92.5%, 45.7% and 7.0%, and 5.4%, 10.9% and 54.0%, respectively. The losses of space-time windows of canopy saturated PAR resulted in a decrease in winter wheat yield, respectively, by 46.2%, 39.6% and 26.3%, 24.7%, 32.4% and 37.6%. The results of the study suggested that the differences in the degree of shading of jujube plants were the causes of the differences in yield reductions of winter wheat. The lighting quality in the west side of winter wheat strip in intercropping system was better than that in the east side during the whole growth period. As a result, jujube could be properly trimmed after winter wheat flowering and the east spacing appropriately increased, not only to control the over growth of new jujube branches, but also to improve winter wheat canopy PAR interception. This could ensure high yield of winter wheat under intercropping system of jujube and winter wheat.
2016, 24(2): 192-200.
Abstract:
Biomass and NPP (net primary productivity) are the primary data which describe the structure and function of ecosystems. The allocations of biomass and NPP are related to nutrient, water use efficiencies and the ability to resist erosion of ecosystems. Excessive farming has intensified wind-erosion desertification in northern China, which has not only affected local economic development and ecological conditions, but also posed threat to the ecological state of the inland areas. Re-grassing abandoned croplands has been a common measure to prevent wind-erosion-caused desertification in the agro-pastoral ecotone of northern China. Grassland vegetation is very sensitive to nitrogen and water in arid and semiarid areas, but is unclear whether and how nitrogen (N) fertilization and increased precipitation affect the restoration of vegetation in re-grassed croplands. The responses of biomass and NPP to N fertilization [N10: 10 g(N).m-2.a-1] and irrigation (irrigation amount was 180 mm to simulate 50% increase in precipitation) were investigated in a re-grassed abandoned cropland in Duolun County of Inner Mongolia, China. The results showed that fertilization increased the aboveground biomass of re-grassed croplands by nearly 100% while irrigation increased aboveground biomass by only 17%–37%. Either fertilization or irrigation had no significant effect on belowground biomass in re-grassed croplands (P > 0.05) while irrigation enhanced belowground NPP (BNPP) by 35%–90%. Fertilization reduced root-to-shoot ratio (R︰S) and ratio of BNPP to aboveground NPP (ANPP) in re-grassed cropland but increased precipitation had no significant effect on the two indicators (P > 0.05). The dominant species (Agropyron mongolicum and Artemisia scoparia) had significant positive responses to fertilization, respectively with 130% and 70% increase in biomass in the second year. However, fertilization had no significant effect on biomass of forbs (P > 0.05). Asymmetric competition for fertilizer among plant species increased the proportion of perennial grass and decreased the proportion of forbs in vegetation community of re-grassed cropland. In contrast, forbs were very sensitive to irrigation, with 128% increase in biomass in the second year of treatments. Increased precipitation enhanced the proportion of forbs in the community by 13%. A. mongolicum and A. scoparia biomass was not affected by increased summer precipitation. Belowground biomass, BNPP, total NPP (TNPP) and R︰S ratio of treated or untreated re-grassed croplands were much lower than those of fenced grassland. The results indicated that fertilization significantly increased aboveground biomass and changed the proportions of biomass and NPP in re-grassed farmlands. The results also suggested that increased precipitation hastened vegetation restoration in abandoned croplands. This strongly depended on functional types of dominant species due to the distinct sensitivity of plant species to increased precipitation.
Biomass and NPP (net primary productivity) are the primary data which describe the structure and function of ecosystems. The allocations of biomass and NPP are related to nutrient, water use efficiencies and the ability to resist erosion of ecosystems. Excessive farming has intensified wind-erosion desertification in northern China, which has not only affected local economic development and ecological conditions, but also posed threat to the ecological state of the inland areas. Re-grassing abandoned croplands has been a common measure to prevent wind-erosion-caused desertification in the agro-pastoral ecotone of northern China. Grassland vegetation is very sensitive to nitrogen and water in arid and semiarid areas, but is unclear whether and how nitrogen (N) fertilization and increased precipitation affect the restoration of vegetation in re-grassed croplands. The responses of biomass and NPP to N fertilization [N10: 10 g(N).m-2.a-1] and irrigation (irrigation amount was 180 mm to simulate 50% increase in precipitation) were investigated in a re-grassed abandoned cropland in Duolun County of Inner Mongolia, China. The results showed that fertilization increased the aboveground biomass of re-grassed croplands by nearly 100% while irrigation increased aboveground biomass by only 17%–37%. Either fertilization or irrigation had no significant effect on belowground biomass in re-grassed croplands (P > 0.05) while irrigation enhanced belowground NPP (BNPP) by 35%–90%. Fertilization reduced root-to-shoot ratio (R︰S) and ratio of BNPP to aboveground NPP (ANPP) in re-grassed cropland but increased precipitation had no significant effect on the two indicators (P > 0.05). The dominant species (Agropyron mongolicum and Artemisia scoparia) had significant positive responses to fertilization, respectively with 130% and 70% increase in biomass in the second year. However, fertilization had no significant effect on biomass of forbs (P > 0.05). Asymmetric competition for fertilizer among plant species increased the proportion of perennial grass and decreased the proportion of forbs in vegetation community of re-grassed cropland. In contrast, forbs were very sensitive to irrigation, with 128% increase in biomass in the second year of treatments. Increased precipitation enhanced the proportion of forbs in the community by 13%. A. mongolicum and A. scoparia biomass was not affected by increased summer precipitation. Belowground biomass, BNPP, total NPP (TNPP) and R︰S ratio of treated or untreated re-grassed croplands were much lower than those of fenced grassland. The results indicated that fertilization significantly increased aboveground biomass and changed the proportions of biomass and NPP in re-grassed farmlands. The results also suggested that increased precipitation hastened vegetation restoration in abandoned croplands. This strongly depended on functional types of dominant species due to the distinct sensitivity of plant species to increased precipitation.
2016, 24(2): 201-209.
Abstract:
The aim of organic agriculture is to augment ecological processes which foster plant nutrient uptake and conserve soil and water resources by eliminating agrochemicals and reducing other external inputs. However, the superiority of organic agriculture in terms of resources utilization is still unclear. Thus this study established an evaluation index system of agricultural resources utilization efficiency and used it to compare the properties of agricultural resources utilization between conventional and organic rice cultivation systems. In the first case, the study systematically analyzed resources behavioral patterns under rice cultivation processes and the existing evaluation index system. In the analysis, 6 evaluation factors (including 18 indices) were selected for the evaluation index system. The Delphi method and Analytic Hierarchy Process (AHP) were used to determine weight coefficient of each index. The weight coefficient of climate resources factors was 16%, which included light use efficiency, heat use efficiency and rain use efficiency. The weight coefficient of water resources factors was 19%, which included irrigation index and water productivity index. Land resources factors (including reclamation rate, land productivity and multi-cropping index) had the highest weight coefficient (24%) in the evaluated index system. The weight coefficient of biotic resources factors was 19%, which included the Shannon-wiener index, economic yield and straw return rate. Labor cost factors (including input-output ratio, labor productivity, scientific technology contribution and agricultural commodity rate) accounted for 16% of the weight coefficient system. Resources sustainability factors (including soil nutrient balance, water environmental quality and resource stability) gave the lowest weight coefficient (10%) in the evaluated index system. In the second case, an empirical analysis was carried out in Hubei Province using the index system to compare resource utilization efficiency between organic and conventional rice cultivation systems in different years. Some 39 samples, which included 8 organic rice cultivation samples (4 samples from organic certification under 3 years, 1 sample from organic certification over 6 years, 4 samples from organic certification for 3 to 6 years) and 31 conventional rice cultivation samples, were used in the analysis. The results showed that the scores of organic cultivation for climate and land resources were lower than that of conventional cultivation. This was attributed to the lower biomass yield in organic cultivation; and the much higher scores of organic cultivation for water resources, biotic resources, labor cost and the related sustainability. Generally, the evaluation score of comprehensive utilization of resources of the 3-year organic rice cultivation was 0.867, similar to that of conventional rice cultivation (0.857). However, the evaluation score increased gradually with cultivation time (the evaluation score of 3 to 6 years organic cultivation was 0.927) and peaked (0.976) in over 6 years organic cultivation, which represented an increase of 14% compared with conventional cultivation. The results suggested that organic agriculture was superior to conventional agriculture in terms of resource utilization efficiency, but this difference was not obvious in the early stages of organic cultivation. The comprehensive utilization efficiency of resources of organic model developed in this study would be more applicable after long-term cultivation.
The aim of organic agriculture is to augment ecological processes which foster plant nutrient uptake and conserve soil and water resources by eliminating agrochemicals and reducing other external inputs. However, the superiority of organic agriculture in terms of resources utilization is still unclear. Thus this study established an evaluation index system of agricultural resources utilization efficiency and used it to compare the properties of agricultural resources utilization between conventional and organic rice cultivation systems. In the first case, the study systematically analyzed resources behavioral patterns under rice cultivation processes and the existing evaluation index system. In the analysis, 6 evaluation factors (including 18 indices) were selected for the evaluation index system. The Delphi method and Analytic Hierarchy Process (AHP) were used to determine weight coefficient of each index. The weight coefficient of climate resources factors was 16%, which included light use efficiency, heat use efficiency and rain use efficiency. The weight coefficient of water resources factors was 19%, which included irrigation index and water productivity index. Land resources factors (including reclamation rate, land productivity and multi-cropping index) had the highest weight coefficient (24%) in the evaluated index system. The weight coefficient of biotic resources factors was 19%, which included the Shannon-wiener index, economic yield and straw return rate. Labor cost factors (including input-output ratio, labor productivity, scientific technology contribution and agricultural commodity rate) accounted for 16% of the weight coefficient system. Resources sustainability factors (including soil nutrient balance, water environmental quality and resource stability) gave the lowest weight coefficient (10%) in the evaluated index system. In the second case, an empirical analysis was carried out in Hubei Province using the index system to compare resource utilization efficiency between organic and conventional rice cultivation systems in different years. Some 39 samples, which included 8 organic rice cultivation samples (4 samples from organic certification under 3 years, 1 sample from organic certification over 6 years, 4 samples from organic certification for 3 to 6 years) and 31 conventional rice cultivation samples, were used in the analysis. The results showed that the scores of organic cultivation for climate and land resources were lower than that of conventional cultivation. This was attributed to the lower biomass yield in organic cultivation; and the much higher scores of organic cultivation for water resources, biotic resources, labor cost and the related sustainability. Generally, the evaluation score of comprehensive utilization of resources of the 3-year organic rice cultivation was 0.867, similar to that of conventional rice cultivation (0.857). However, the evaluation score increased gradually with cultivation time (the evaluation score of 3 to 6 years organic cultivation was 0.927) and peaked (0.976) in over 6 years organic cultivation, which represented an increase of 14% compared with conventional cultivation. The results suggested that organic agriculture was superior to conventional agriculture in terms of resource utilization efficiency, but this difference was not obvious in the early stages of organic cultivation. The comprehensive utilization efficiency of resources of organic model developed in this study would be more applicable after long-term cultivation.
YANG Gang,
SHI Penghui,
SUN Wancang,
LIU Zigang,
ZENG Xiucun,
WU Junyan,
FANG Yan,
LI Xuecai,
CHEN Qi,
LIU Linbo,
YANG Jiansheng,
FANG Yuan,
ZHANG Juan
2016, 24(2): 210-217.
Abstract:
The objective of this paper was to lay the basis for studying cold resistance of winter rapeseed. The anti-freeze activities of apoplast proteins were determined in the ‘Longyou 6’ winter rape leaves and roots under cold vernalization. The apoplast proteins were separated by SDS-PAGE and high expression proteins identified in MALDI-TOF/TOF mass spectrometry under field and pot experiments. The results showed that apoplast protein content of ‘Longyou 6’ leaves increased significantly (P < 0.05) after cold acclimation in an artificial climate chamber, reaching 92.31 μgg-1(FW) on the fifth day, which represented an increase of 246.12% over CK. Apoplast protein content after 10–15 days of cold acclimation dropped compared with that after 5 days, but was still significantly higher than that of CK (P < 0.05). Apoplast protein content continued to increase with increasing cold acclimation time from 20 to 25 days (P < 0.05). Apoplast protein content decreased significantly with after 10 days of de-acclimation. In the process of cold acclimation, apoplast protein content of ‘Longyou 6’ leaves significantly accumulated. However, it decreased significantly after de-acclimation. Obviously, apoplast proteins of ‘Longyou 6’ winter rape belonged to low temperature induced proteins. Anti-freeze activity detection analysis suggested that apoplast proteins had re-crystallization inhibition activity. Mass spectrometry identification revealed a variety of proteins with unclear functions along with β-1-3-glucanase consistent anti-freeze proteins reported in winter rye. The class glucanase detected by mass spectrometry was found to have weaker ice crystal forms due to modification effect with reclamation and anti-freeze activity test. The test suggested that this class glucanase was a low activity anti-freeze protein. Many anti-freeze proteins were synthesized and secreted by winter rape in apoplast of leaves and roots under low temperature stress. The proteins likely played a positive role against outside low temperature. Furthermore, it was speculated that there were many undetected anti-freeze apoplast proteins responsible for the strong winter hardiness of winter rapeseed.
The objective of this paper was to lay the basis for studying cold resistance of winter rapeseed. The anti-freeze activities of apoplast proteins were determined in the ‘Longyou 6’ winter rape leaves and roots under cold vernalization. The apoplast proteins were separated by SDS-PAGE and high expression proteins identified in MALDI-TOF/TOF mass spectrometry under field and pot experiments. The results showed that apoplast protein content of ‘Longyou 6’ leaves increased significantly (P < 0.05) after cold acclimation in an artificial climate chamber, reaching 92.31 μgg-1(FW) on the fifth day, which represented an increase of 246.12% over CK. Apoplast protein content after 10–15 days of cold acclimation dropped compared with that after 5 days, but was still significantly higher than that of CK (P < 0.05). Apoplast protein content continued to increase with increasing cold acclimation time from 20 to 25 days (P < 0.05). Apoplast protein content decreased significantly with after 10 days of de-acclimation. In the process of cold acclimation, apoplast protein content of ‘Longyou 6’ leaves significantly accumulated. However, it decreased significantly after de-acclimation. Obviously, apoplast proteins of ‘Longyou 6’ winter rape belonged to low temperature induced proteins. Anti-freeze activity detection analysis suggested that apoplast proteins had re-crystallization inhibition activity. Mass spectrometry identification revealed a variety of proteins with unclear functions along with β-1-3-glucanase consistent anti-freeze proteins reported in winter rye. The class glucanase detected by mass spectrometry was found to have weaker ice crystal forms due to modification effect with reclamation and anti-freeze activity test. The test suggested that this class glucanase was a low activity anti-freeze protein. Many anti-freeze proteins were synthesized and secreted by winter rape in apoplast of leaves and roots under low temperature stress. The proteins likely played a positive role against outside low temperature. Furthermore, it was speculated that there were many undetected anti-freeze apoplast proteins responsible for the strong winter hardiness of winter rapeseed.
2016, 24(2): 218-225.
Abstract:
The aim of this study was to explore the effects of nitrogen application on Cd uptake by different kinds of leafy vegetables and on soil available cadmium (Cd) content in above-standard Cd-contaminated soils in vegetable fields. The study also comprehensively evaluated the effects of different nitrogen sources application with the aim of developing strategies to reduce Cd concentration in leafy vegetables by managing the application of nitrogen fertilizers. The experiment was carried out in an above-standard Cd-contaminated vegetable soil to investigate the effects of urea [CO(NH2)2], calcium nitrate [Ca(NO3)2], ammonium nitrate (NH4NO3) and ammonium bicarbonate (NH4HCO3) on yield, quality, Cd content, nitrogen content of two kinds of leafy vegetables — Brassica chinensis L. (BC) and Amaranthus mangostanus L. (AM). Soil DTPA-Cd content and pH as well as comprehensive effects of nitrogen addition on two vegetables were also investigated. The results showed that all nitrogen sources increased yields and decreased Cd contents in both shoot and root systems of the two leafy vegetables. Furthermore, the highest increase of BC yield (59.7%) was caused by NH4HCO3 treatment, while the largest increase of AM yield (47.5%) was caused by CO(NH2)2 treatment, respectively, compared with control. However, the lowest Cd contents in two kinds of leafy vegetables were observed under Ca(NO3)2 treatment among all nitrogen treatments. Ca(NO3)2 decreased Cd content by 41.6% and 24.2%, respectively, in AM shoot and root, by 32.2% and 25.9%, respectively, in BC shoot and root. Moreover, the total content of Cd, nitrate, nitrite, Vitamin C and soluble sugar in the shoot system of the two kinds of leafy vegetables varied with the application of different nitrogen resources. Also similar variances were noted for the changes in soil pH and DTPA-Cd content. NH4NO3 application decreased soil pH by 0.12 and 0.25 and increased soil DTPA-Cd content by 15.3% and 14.6%, respectively, in AM and BC. However, the reverse trend was noted under NH4HCO3 treatment. Comprehensive evaluation results showed that the four kinds of nitrogen resources had much higher synthetic weighted value than that of control. Among all treatments, the highest value was observed in Ca(NO3)2 treatment, which suggested that Ca(NO3)2 had the best comprehensive application effect in above-standard Cd-contaminated soils. Thus Ca(NO3)2 could be used as optimum nitrogen source in above-standard Cd-contaminated soils in vegetable fields.
The aim of this study was to explore the effects of nitrogen application on Cd uptake by different kinds of leafy vegetables and on soil available cadmium (Cd) content in above-standard Cd-contaminated soils in vegetable fields. The study also comprehensively evaluated the effects of different nitrogen sources application with the aim of developing strategies to reduce Cd concentration in leafy vegetables by managing the application of nitrogen fertilizers. The experiment was carried out in an above-standard Cd-contaminated vegetable soil to investigate the effects of urea [CO(NH2)2], calcium nitrate [Ca(NO3)2], ammonium nitrate (NH4NO3) and ammonium bicarbonate (NH4HCO3) on yield, quality, Cd content, nitrogen content of two kinds of leafy vegetables — Brassica chinensis L. (BC) and Amaranthus mangostanus L. (AM). Soil DTPA-Cd content and pH as well as comprehensive effects of nitrogen addition on two vegetables were also investigated. The results showed that all nitrogen sources increased yields and decreased Cd contents in both shoot and root systems of the two leafy vegetables. Furthermore, the highest increase of BC yield (59.7%) was caused by NH4HCO3 treatment, while the largest increase of AM yield (47.5%) was caused by CO(NH2)2 treatment, respectively, compared with control. However, the lowest Cd contents in two kinds of leafy vegetables were observed under Ca(NO3)2 treatment among all nitrogen treatments. Ca(NO3)2 decreased Cd content by 41.6% and 24.2%, respectively, in AM shoot and root, by 32.2% and 25.9%, respectively, in BC shoot and root. Moreover, the total content of Cd, nitrate, nitrite, Vitamin C and soluble sugar in the shoot system of the two kinds of leafy vegetables varied with the application of different nitrogen resources. Also similar variances were noted for the changes in soil pH and DTPA-Cd content. NH4NO3 application decreased soil pH by 0.12 and 0.25 and increased soil DTPA-Cd content by 15.3% and 14.6%, respectively, in AM and BC. However, the reverse trend was noted under NH4HCO3 treatment. Comprehensive evaluation results showed that the four kinds of nitrogen resources had much higher synthetic weighted value than that of control. Among all treatments, the highest value was observed in Ca(NO3)2 treatment, which suggested that Ca(NO3)2 had the best comprehensive application effect in above-standard Cd-contaminated soils. Thus Ca(NO3)2 could be used as optimum nitrogen source in above-standard Cd-contaminated soils in vegetable fields.
2016, 24(2): 226-234.
Abstract:
The understanding of characteristics of heavy metal transfer in soil-rice systems can improve soil quality in production areas and guide the safe production of rice. We collected soil and rice samples from three typical rice production areas (Nanxun, Shengzhou and Wenling) located in the northern, central and southern parts of Zhejiang Province. The controlling factors of heavy metal transfer were studied based on a transfer model set up for hybrid rice and japonica rice. The objective of the study was to identify transfer traits of heavy metals in soil-rice systems in typical rice production areas in Zhejiang Province and to guide safe agricultural production. The results suggested that the physico-chemical properties were different in the three areas. pH (mean value of 5.52), organic matter (mean value of 39.4 gkg-1), EC and heavy metal fractions contents in soil in Shengzhou area were lower than those in the other two production areas. Sand content of soil in Shengzhou area was higher than that in the other two areas. Heavy metals in soils and rice were significantly different from each other of rice production areas. Heavy metals (Cd, Cu and Zn) contents in soil in Wenling area were significantly higher than those in the other two areas. Then heavy metals contents in rice in Shengzhou area were significantly higher than those in Nanxun area (P < 0.05). No carbonate bound fraction of heavy metals was detected in the study. The corresponding contents of exchangeable, Fe-Mn oxide bound, organic bound, and residual fractions of heavy metals in Shengzhou were lower than those in the other two production areas due to the lowest total heavy metals contents in Shengzhou soil. The enrichment indexes (EI) of heavy metals were different in the three production areas. Generally, EIs of Cd and Zn were higher than those of Cu and Ni. Also EIs in Shengzhou area (range of 0.018–0.521) were significantly higher than those in the other two areas (range of 0.004–0.143 for Nanxun area and of 0.007–0.269 for Wenling area). Both soil physico-chemical properties and heavy metals fractions were important factors influencing heavy metal enrichment indexes. Compared with heavy metals fractions, soil physico-chemical properties contributed more to the movement of heavy metals in soil-rice systems. A log-linear model of heavy metals combined with the physico-chemical properties and heavy metal fractions well predicted the availability of heavy metals in soil-rice systems under practical production conditions. The accuracy of the model prediction for hybrid rice was better than that for japonica rice. The Ni (regression coefficient r was 0.61 and 0.70 at P < 0.01 for hybrid and japonica rice, respectively) model was better than that of other heavy metals. However, the accuracy of the model prediction of hybrid rice Cd content (r = 0.21 at P > 0.05) was poor. In that case, it was necessary to conduct further research in order to improve the accuracy of the model by either using more of the environmental variables or adjusting the variables.
The understanding of characteristics of heavy metal transfer in soil-rice systems can improve soil quality in production areas and guide the safe production of rice. We collected soil and rice samples from three typical rice production areas (Nanxun, Shengzhou and Wenling) located in the northern, central and southern parts of Zhejiang Province. The controlling factors of heavy metal transfer were studied based on a transfer model set up for hybrid rice and japonica rice. The objective of the study was to identify transfer traits of heavy metals in soil-rice systems in typical rice production areas in Zhejiang Province and to guide safe agricultural production. The results suggested that the physico-chemical properties were different in the three areas. pH (mean value of 5.52), organic matter (mean value of 39.4 gkg-1), EC and heavy metal fractions contents in soil in Shengzhou area were lower than those in the other two production areas. Sand content of soil in Shengzhou area was higher than that in the other two areas. Heavy metals in soils and rice were significantly different from each other of rice production areas. Heavy metals (Cd, Cu and Zn) contents in soil in Wenling area were significantly higher than those in the other two areas. Then heavy metals contents in rice in Shengzhou area were significantly higher than those in Nanxun area (P < 0.05). No carbonate bound fraction of heavy metals was detected in the study. The corresponding contents of exchangeable, Fe-Mn oxide bound, organic bound, and residual fractions of heavy metals in Shengzhou were lower than those in the other two production areas due to the lowest total heavy metals contents in Shengzhou soil. The enrichment indexes (EI) of heavy metals were different in the three production areas. Generally, EIs of Cd and Zn were higher than those of Cu and Ni. Also EIs in Shengzhou area (range of 0.018–0.521) were significantly higher than those in the other two areas (range of 0.004–0.143 for Nanxun area and of 0.007–0.269 for Wenling area). Both soil physico-chemical properties and heavy metals fractions were important factors influencing heavy metal enrichment indexes. Compared with heavy metals fractions, soil physico-chemical properties contributed more to the movement of heavy metals in soil-rice systems. A log-linear model of heavy metals combined with the physico-chemical properties and heavy metal fractions well predicted the availability of heavy metals in soil-rice systems under practical production conditions. The accuracy of the model prediction for hybrid rice was better than that for japonica rice. The Ni (regression coefficient r was 0.61 and 0.70 at P < 0.01 for hybrid and japonica rice, respectively) model was better than that of other heavy metals. However, the accuracy of the model prediction of hybrid rice Cd content (r = 0.21 at P > 0.05) was poor. In that case, it was necessary to conduct further research in order to improve the accuracy of the model by either using more of the environmental variables or adjusting the variables.
2016, 24(2): 235-243.
Abstract:
There is limited development of agricultural economy in the north area of China that has been irrigated with sewage water for a long time, because of the uneven distribution of water resources and different levels of soil pollution. The main contaminants of sewage irrigation are heavy metals, which contamination area has been expanding over the years. A number of large-scale or multi-scale studies have been conducted on heavy metal pollution in surface soils in irrigated areas. However, studies have less focused on the vertical distribution of heavy metal, but mainly concentrated on the characteristics of migration and leaching of heavy metals in the soil. It is therefore necessary to focus on the vertical cross-sectional view of the spatial variability of soil heavy metals in sewage irrigated areas on a small scale. In this study, we investigated the spatial variability and distribution of available cadmium in the soil after once sewage irrigation. Using classical statistics and geo-statistical techniques, we measured the spatial variability and distribution in a 328 m2 field in the Niangniangmiao sewage irrigation area in Xinxiang, Henan Province. The classical statistical analysis suggested that the mean available cadmium in soil sections A, B, C and D (the south-north sections with 10.5 m away from each other and across the field from north to south) decreased, respectively, by 0.06 mgkg-1, 0.11 mgkg-1, 0.14 mgkg-1 and 0.23 mgkg-1 after sewage irrigation; suggesting a moderate degree of dispersion. The dispersion in soil section B increased by 4.32%, while it decreased in other sections by 9.39% (A), 6.12% (C) and 10.98% (D), all of which were within the 28.31%45.16% range after sewage irrigation. Geo-statistical analysis showed that the overall variation in available cadmium in the soil sections was random, C0/(C0+C) < 25%. Soil available cadmium had a strong spatial correlation within the 0.3931.308 m range. The optimal empirical semi-variogarm models for simulating soil cadmium content for soil sections A, B, C and D were respectively spherical, spherical, Gaussian and exponential modles. Soil profile B had the highest (1.997) fractal dimension of available cadmium. The fractal dimension decreased after sewage irrigation suggesting a weakening spatial variability of soil available cadmium. Structural factors played a decisive role in the vertical spatial variability and distribution of available cadmium in the soil sections. Kriging interpolation suggested a banded distribution pattern. There was significant available cadmium accumulation in the 015 cm soil layer. The distribution contour of available cadmium in the soil sections varied from dense to sparse along irrigation direction. Correlation and variance analysis showed that available cadmium content was positively correlated with organic matter content, moderately correlated with soil moisture, strongly negatively correlated with pH. The effect of irrigation on each factor was significantly, moreover, irrigation could dampen the impact of the factors on available cadmium. The results on distribution and variation in soil available cadmium showed leaching and migration of soil available cadmium after sewage irrigation. This was more visible for the 015 cm top soil than the 3040 cm sub-soil. The spatial variability of soil available cadmium was mainly influenced by soil structural factors. The study provided the primary investigation for phytoremediation of heavy metal in polluted soils.
There is limited development of agricultural economy in the north area of China that has been irrigated with sewage water for a long time, because of the uneven distribution of water resources and different levels of soil pollution. The main contaminants of sewage irrigation are heavy metals, which contamination area has been expanding over the years. A number of large-scale or multi-scale studies have been conducted on heavy metal pollution in surface soils in irrigated areas. However, studies have less focused on the vertical distribution of heavy metal, but mainly concentrated on the characteristics of migration and leaching of heavy metals in the soil. It is therefore necessary to focus on the vertical cross-sectional view of the spatial variability of soil heavy metals in sewage irrigated areas on a small scale. In this study, we investigated the spatial variability and distribution of available cadmium in the soil after once sewage irrigation. Using classical statistics and geo-statistical techniques, we measured the spatial variability and distribution in a 328 m2 field in the Niangniangmiao sewage irrigation area in Xinxiang, Henan Province. The classical statistical analysis suggested that the mean available cadmium in soil sections A, B, C and D (the south-north sections with 10.5 m away from each other and across the field from north to south) decreased, respectively, by 0.06 mgkg-1, 0.11 mgkg-1, 0.14 mgkg-1 and 0.23 mgkg-1 after sewage irrigation; suggesting a moderate degree of dispersion. The dispersion in soil section B increased by 4.32%, while it decreased in other sections by 9.39% (A), 6.12% (C) and 10.98% (D), all of which were within the 28.31%45.16% range after sewage irrigation. Geo-statistical analysis showed that the overall variation in available cadmium in the soil sections was random, C0/(C0+C) < 25%. Soil available cadmium had a strong spatial correlation within the 0.3931.308 m range. The optimal empirical semi-variogarm models for simulating soil cadmium content for soil sections A, B, C and D were respectively spherical, spherical, Gaussian and exponential modles. Soil profile B had the highest (1.997) fractal dimension of available cadmium. The fractal dimension decreased after sewage irrigation suggesting a weakening spatial variability of soil available cadmium. Structural factors played a decisive role in the vertical spatial variability and distribution of available cadmium in the soil sections. Kriging interpolation suggested a banded distribution pattern. There was significant available cadmium accumulation in the 015 cm soil layer. The distribution contour of available cadmium in the soil sections varied from dense to sparse along irrigation direction. Correlation and variance analysis showed that available cadmium content was positively correlated with organic matter content, moderately correlated with soil moisture, strongly negatively correlated with pH. The effect of irrigation on each factor was significantly, moreover, irrigation could dampen the impact of the factors on available cadmium. The results on distribution and variation in soil available cadmium showed leaching and migration of soil available cadmium after sewage irrigation. This was more visible for the 015 cm top soil than the 3040 cm sub-soil. The spatial variability of soil available cadmium was mainly influenced by soil structural factors. The study provided the primary investigation for phytoremediation of heavy metal in polluted soils.
2016, 24(2): 244-255.
Abstract:
China is one of the countries in the world with the most severe soil erosion. Mastering various changes in regional soil erosion, soil conservation and ecological dynamics is critical for prioritization of regional soil and water conservation in time and space to combat soil erosion for sustainable development. At present, research on long-term soil conservation has ignored the erosion force of rainfall and the dynamic changes in vegetation coverage. Using GIS and Universal Soil Loss Equation (USLE), we calculated soil erosion and soil conservation amounts in a typical coastal saline soil region, Huanghua City of Hebei Province. Furthermore, using market value and soil opportunity cost, we calculated monthly soil conservation value in the study area. The dynamic characteristics of soil conservation in coastal land ecosystems were important for ecological security and the maintenance of China’s coastal areas. The results showed uneven monthly distribution of soil conservation values that was in agreement with the seasonal dynamics of soil conservation amount which peaked in August. The soil conservation value was zero for January, February, March, October, and December, while it increased from May to August. Soil conservation value from May to September accounted for 82.47% of the total of the year. Among different ecosystems, grassland showed the highest soil conservation value per unit area in August (128.87 Yuan·hm-2). The soil conservation value per unit area of water body was minimum in September (11.23 Yuan·hm-2). For different functions of soil conservation, the order of value contributions to soil conservation value per unit area was value of reducing soil fertility loss > value of reducing silt deposition > value of reducing land abandonment. The soil conservation values of different ecosystems in the study area changed obviously with season. In the rainy season, the heavy short-durational rains increased soil loss, when the soil conservation functions of ecosystems were more important for combating soil loss.
China is one of the countries in the world with the most severe soil erosion. Mastering various changes in regional soil erosion, soil conservation and ecological dynamics is critical for prioritization of regional soil and water conservation in time and space to combat soil erosion for sustainable development. At present, research on long-term soil conservation has ignored the erosion force of rainfall and the dynamic changes in vegetation coverage. Using GIS and Universal Soil Loss Equation (USLE), we calculated soil erosion and soil conservation amounts in a typical coastal saline soil region, Huanghua City of Hebei Province. Furthermore, using market value and soil opportunity cost, we calculated monthly soil conservation value in the study area. The dynamic characteristics of soil conservation in coastal land ecosystems were important for ecological security and the maintenance of China’s coastal areas. The results showed uneven monthly distribution of soil conservation values that was in agreement with the seasonal dynamics of soil conservation amount which peaked in August. The soil conservation value was zero for January, February, March, October, and December, while it increased from May to August. Soil conservation value from May to September accounted for 82.47% of the total of the year. Among different ecosystems, grassland showed the highest soil conservation value per unit area in August (128.87 Yuan·hm-2). The soil conservation value per unit area of water body was minimum in September (11.23 Yuan·hm-2). For different functions of soil conservation, the order of value contributions to soil conservation value per unit area was value of reducing soil fertility loss > value of reducing silt deposition > value of reducing land abandonment. The soil conservation values of different ecosystems in the study area changed obviously with season. In the rainy season, the heavy short-durational rains increased soil loss, when the soil conservation functions of ecosystems were more important for combating soil loss.
2016, 24(2): 256-264.
doi: 10.13930/j.cnki.cjea.150868
Abstract:
Unused land is not only an important land resource reserve, but also an important part of the ecosystem. Unused land plays an important role in easing land supply and supporting ecological stability. However, the ecological importance of unused lands has not been given due attention. Studies on unused lands have mainly focused on the evaluation of the suitability for exploitation as arable and construction lands. Most of the studies have failed to give enough attention to the ecological value of unused lands. This study used Guyuan County in Hebei Province (a transition ecotone between agriculture and animal husbandry with severe ecological problems) to assess the importance of construction and protection of ecological environment. The recognition of ecological importance of unused lands was not only important for the development of unused lands, but also for the construction of ecological environment in Guyuan County. Based on the ecological conditions in Guyuan County, the study used disaster protection, human interference and habitat and water protection as indicators to determine the ecological importance of unused lands. Combined with spatial analysis in GIS and the spatial strengths of the indicators of ecological importance, the study determined the ecological importance of unused lands in Guyuan County and grouped the lands into 4 categories ― very important, important, relatively important and less important. Based on terrain features of Guyuan County, this study divided the elevation and slope factors into 4 zones each (1 2001 400 m、1 4001 600 m、1 600 1 800 m and 1 800 m in elevation; 0°5°、5°15°、15°25° and >25° in slope gradient), which were used to analyze the characteristics of unused lands ecological importance in different terrain gradients. The results showed that the areas of unused lands with very important, important, relatively important and less important levels were respectively, 11 082.78 hm2, 11 209.05 hm2, 11 450.25 hm2 and 4 803.12 hm2, and accounting for 28.75%, 29.08%, 29.71% and 12.46% of total unused land in Guyuan County. The area marked as less ecological importance was low. According to the analysis on the base of terrain factors, unused lands were mainly distributed in the 1 400–1 600 m elevation zone and the 0°–5° and 5°–15° slope zones. The unused lands in Guyuan County with very ecological importance were mainly distributed in the 1 400–1 600 m and 1 600–1 800 m elevation zones and the 5°–15° slope zone. With increased elevation and slope, the proportion of unused lands with very ecological importance changed greatly, increasing from 11.31% to 97.95% and from 13.86% to 93.64%. Most of the unused lands in Guyuan County were important for the ecology and there was the need to pay keen attention to the ecological environment when using the unused lands. These results provided scientific guidance to the development of unused lands and the construction of ecological environment in Guyuan County.
Unused land is not only an important land resource reserve, but also an important part of the ecosystem. Unused land plays an important role in easing land supply and supporting ecological stability. However, the ecological importance of unused lands has not been given due attention. Studies on unused lands have mainly focused on the evaluation of the suitability for exploitation as arable and construction lands. Most of the studies have failed to give enough attention to the ecological value of unused lands. This study used Guyuan County in Hebei Province (a transition ecotone between agriculture and animal husbandry with severe ecological problems) to assess the importance of construction and protection of ecological environment. The recognition of ecological importance of unused lands was not only important for the development of unused lands, but also for the construction of ecological environment in Guyuan County. Based on the ecological conditions in Guyuan County, the study used disaster protection, human interference and habitat and water protection as indicators to determine the ecological importance of unused lands. Combined with spatial analysis in GIS and the spatial strengths of the indicators of ecological importance, the study determined the ecological importance of unused lands in Guyuan County and grouped the lands into 4 categories ― very important, important, relatively important and less important. Based on terrain features of Guyuan County, this study divided the elevation and slope factors into 4 zones each (1 2001 400 m、1 4001 600 m、1 600 1 800 m and 1 800 m in elevation; 0°5°、5°15°、15°25° and >25° in slope gradient), which were used to analyze the characteristics of unused lands ecological importance in different terrain gradients. The results showed that the areas of unused lands with very important, important, relatively important and less important levels were respectively, 11 082.78 hm2, 11 209.05 hm2, 11 450.25 hm2 and 4 803.12 hm2, and accounting for 28.75%, 29.08%, 29.71% and 12.46% of total unused land in Guyuan County. The area marked as less ecological importance was low. According to the analysis on the base of terrain factors, unused lands were mainly distributed in the 1 400–1 600 m elevation zone and the 0°–5° and 5°–15° slope zones. The unused lands in Guyuan County with very ecological importance were mainly distributed in the 1 400–1 600 m and 1 600–1 800 m elevation zones and the 5°–15° slope zone. With increased elevation and slope, the proportion of unused lands with very ecological importance changed greatly, increasing from 11.31% to 97.95% and from 13.86% to 93.64%. Most of the unused lands in Guyuan County were important for the ecology and there was the need to pay keen attention to the ecological environment when using the unused lands. These results provided scientific guidance to the development of unused lands and the construction of ecological environment in Guyuan County.
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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