中国生态农业学报(中英文)

Effects of different concentrations of nitrogen and soil moistures on paddy soil nitrification and microbial characteristics

LI Fang-Liang, LI Zhong-Pei, LIU Ming, JIANG Chun-Yu

2012, 20(9): 1113-1118. doi: 10.3724/SP.J.1011.2012.01113

Abstract(1326) PDF(1253)

Abstract:
To make clear the effects of different concentrations of nitrogen and soil moistures on soil nitrification and microbial characteristics, especially the responses to high nitrogen concentration, nitrification, microbial biomass carbon and microbial community diversity in red paddy soils were studied under four ammonium sulfate doses [0(CK), 120 mg(N)·kg^-1 (A1), 600 mg(N)·kg^-1 (A2), 1 200 mg(N)·kg^-1 (A3)] and adjusted soil moistures of 40%, 60% and 80% of water holding capacity (WHC). Nitrification ratios and rates of A2 and A3 treatments were generally low under 40%, 60% and 80% WHC. Nitrification ratios and rates of A1 treatments significantly increased with increasing soil moisture. Nitrification significantly decreased with decreasing ammonium sulfate at constant soil moisture. Soil microbial biomass carbon reduced with increasing ammonium sulfate from 40%, 60% to 80%WHC. The trend in microbial biomass carbon at constant ammonium sulfate concentration was 60%WHC > 80%WHC > 40%WHC. No interactive effects were noted in the soil moisture and ammonium sulfate treatments. For different concentrations of nitrogen and soil moistures, BIOLOG analysis showed that AWCD value and Shannon, Simpson, McIntosh indices were highest under A1 treatment at 60%WHC, followed by CK treatment at 60%WHC. For different soil moisture, excessive fertilization led to low microbial activity. AWCD value and Shannon, Simpson, McIntosh indices were low under A2 and A3 ammonium sulfate treatments. The findings suggested different soil biological and biochemical properties under different concentrations of nitrogen and soil moistures. Overuse of chemical fertilizers did no enhance soil biological properties and biochemical function.

Dissolution characteristics of phosphate rocks in latosols withdifferent parent materials in rubber plantations

ZHOU Jie, GUO Hai-Chao, LUO Xue-Hua, WANG Wen-Bin, WU Xiao-Ping

2012, 20(9): 1119-1126. doi: 10.3724/SP.J.1011.2012.01119

Abstract(1558) PDF(1508)

Abstract:
Latosols are very acidic, often extremely deficient in phosphorus (P) and have strong P sorption capacity. The state of P in latosols is one of the main limiting factors of growth and yield of rubber trees. Several studies have suggested that phosphate rocks (PR) could be as effective as water soluble phosphate fertilizers in increasing plant yield and improving soil P content in tropical regions. Although water soluble P is the mainly P fertilizer used for improving the state of nitrites in rubber trees, rational use of PR has not been intensively researched. PR application proved promising particularly in tropical plantations and organic agriculture in China. This research simulated and assessed dissolution and availability extents and rates of two PR forms in different latosols from five parent materials. The research also identified major soil factors controlling PR dissolution and availability in tropical soils. The results provided useful information on rational application of PR in tropical crops in China. Thus the dissolution and availability characteristics of two PR forms [Kunyang phosphate rocks (KPR) from Yunnan Province and Wucun phosphate rocks (WPR) from Jiangxi Province] were investigated in laboratory incubation of ten rubber plantation latosols with different parent materials. PR was added to tropical soils at rates of 0 mg(P).kg^-1 (control) and 500 mg(P).kg^-1. The soil-PR mixtures were placed in plastic containers and incubated at moisture content of ≈60% soil water-holding capacity, 25 ℃ and for 35 days. Results showed that dissolution of two forms of PR increased in all the soils with increasing incubation period. The two PR dissolution kinetics in ten types of latosols were best described by the Elovich equation, followed by Langmuir equation. The Mitscherlich equation did not suitably describe PR dissolution in latosols. Average maximum dissolution potentials of the two PRs in latosols from basalt were 2.16, 1.73, 2.49 and 2.39 times of latosols from sand shale, granite, gneiss and nerite, respectively. Maximum dissolutions of the two PRs in latosols were positive correlated with soil organic matter, soil total hydrolytic acidity, free iron oxide content and cation exchange capacity (CEC). Dissolution rates of the two PRs in latosols were positive correlated with soil total hydrolytic acidity, free iron oxide content and CEC. Stepwise multiple regression indicated that soil free iron oxide content was the soil factor with the most significant control over maximum dissolutions of the two PRs. CEC and soil adsorption parameter (K) were respectively the soil factors with the most effect on KPR and WPR dissolution rates in latosols. Soil available P increased after PR application, but the increment was different for the various soils and sampling periods throughout the incubation process. This study thus indicated that better effect was obtainable when PR was applied first in latosols from basalt. Compared with KPR, it was possible for low grade WPR to have the same effect regarding increasing soil available P in latosols.

Effects of winter drought resistant strategies on wheat waterconsumption and growth characteristics

DANG Hong-Kai, ZHENG Chun-Lian, MA Jun-Yong, CAO Cai-Yun, WANG Gui-Feng, LI Wei, LI Ke-Jiang

2012, 20(9): 1127-1134. doi: :10.3724/SP.J.1011.2012.01127

Abstract(1274) PDF(1107)

Abstract:
Water resource deficiency is one of major limitations to winter wheat production in Hebei Lowland Plain Areas. Drought resistant strategies are critical for high yield and quality wheat grain production. The effects of drought resistant measures (sprinkler irrigation at winter plus 75 mm irrigation at revival stage, flood irrigation at winter plus 75 mm irrigation at revival stage, and cattle manure mulching at winter plus 90 mm irrigation at revival stage) with three treatment times in winter (Jan. 28, Feb. 12 and Feb. 27) on water consumption and growth characteristics of "Heng 4399" wheat cultivar was determined in this study under high-yield cultivation conditions in 2010-2011 growth season with 47.7 mm of precipitation. The results showed that total water consumption of wheat for the whole growth period was 384.93~464.24 mm. WUE (water use efficiency) was 15.23~20.87 kg·hm^-2·mm^-1. Periods with the highest water consumption were generally from double ridge to filling and then from sowing to wintering. At same treatments time, treatments with high irrigation amounts increased total water consumption while reducing irrigation WUE. Concurrent comparisons of different treatments showed that WUE under cattle manure mulching was higher than that under other drought resistant measures. Compared with flood irrigation, sprinkler irrigation saved more water and was also more suitable to wheat growth water needs. For the indices of soil water ratio, WUE and IWUE (irrigation water use efficiency), sprinkler irrigation was better than flood irrigation. For the same treatment at different times, there an increasing grain-yield trend was noted with delayed treatment. At a same time, the effects of different treatments on dry-matter accumulation and redistribution were different. Cattle manure mulching and CK treatments increased the relocation of dry-matter accumulated before anthesis to wheat grain. Flood and sprinkler irrigations increased dry-matter accumulation after anthesis and also dry-matter relocation ratio to grain. The above findings provided the theoretical basis for developing winter drought resistant strategies in winter wheat cultivation.

Effects of different pre-winter management practices on soiltemperature and winter wheat seedling growth

LIU Xiu-Wei, MIAO Wen-Fang, WANG Yan-Zhe, SUN Hong-Yong, SHAO Li-Wei, CHEN Su-Ying, ZHANG Xi-Ying

2012, 20(9): 1135-1141. doi: 10.3724/SP.J.1011.2012.01135

Abstract(1329) PDF(1805)

Abstract:
For winter wheat/summer maize double cropping system in the North China Plain (NCP), the practices of straw incorporation into the top soil and minimum tillage have some negative effects on winter wheat growth. This study examined the effects of straw mulching, winter irrigation and soil compaction on soil temperature and winter wheat seedling growth. Results showed that straw mulching reduced both maximum and minimum soil temperature. Compared with CK, straw mulching increased the average daily minimum soil temperature (Tmin) by 2.37 ℃, 3.18 ℃ and 1.68 ℃ at the soil surface and by 0.57 ℃, 1.28 ℃ and 0.34 ℃ at the 5 cm soil layer at pre-wintering, during over-wintering and after winter dormancy, respectively. Straw mulching reduced daily maximum temperature on the average by 2.68 ℃, 4.40 ℃ and 4.82 ℃ at the soil surface and by 0.54 ℃, 0.75 ℃ and 1.85 ℃ at the 5 cm soil depth for the three periods, respectively. Straw mulching reduced soil temperature, which slowed down winter wheat development. Wheat tiller and biomass reduced by 29.8% and 5.2% during recovery. Although straw mulching positively influenced soil water conservation, winter wheat growth was negatively affected. Winter irrigation increased soil moisture, which in turn reduced both the maximum and minimum soil temperature during over-winter and recovery stage of winter wheat. Average daily minimum temperatures were respectively 0.88 ℃ and 0.93 ℃ higher for treatments with winter irrigation than that for treatments without winter irrigation at the soil surface and 5 cm soil layer during over-wintering. For the same treatments, the differences were 5.35 ℃ and 5.57 ℃ during recovery. Wheat tiller number and biomass also reduced by 27.7% and 21.2% during recovery. Good soil moisture after winter irrigation at the recovery stage reduced soil temperature, which negatively affected winter wheat. Soil compaction after winter wheat sowing did not significantly affect soil temperature and winter wheat seedling growth.

Effects of planting density and mode on summer maize chloroplastD1 protein and photo-system II

LI Hong-Qi, PEI Rui-Jie, LIN Hai-Ming, YUAN Li-Gang, HU Wei-Wei, ZHAO Hui-Jie, WANG Jun-Zhong

2012, 20(9): 1142-1148. doi: 10.3724/SP.J.1011.2012.01142

Abstract(1368) PDF(1468)

Abstract:
The effects of different planting densities and modes on grain yield and physiological parameters of two summer maize varieties ("Zhengdan 958" and "Xundan 20") were studied under high yield conditions in North Henan Province. With 67 500~90 000 plants per hm^-2, D1 protein content, optimal photochemical efficiency of PSII (Fv/Fm), photochemical quenching coefficient (qP), photosynthetic rate (Pn) and activities of foliar superoxide dismutase (SOD) decreased. However, peroxidase (POD) activity, non-photochemical quenching (NPQ) and malondialdehyde (MDA) content increased. At the same time, bald needle length increased and ear weight decreased. Yield increased to a peak then decreased with increasing plant density. When plant density exceeded 82 500 plants per hm^-2, Fv/Fm, qP, Pn and SOD activity decreased dramatically. These parameters were lower at densities of 90 000 plants per hm^-2 than at 82 500 plants per hm^-2; dropping by an average from 1.2%~21.7%. NPQ, POD activity, and MDA content increased with increasing plant density. These parameters were also higher at densities of 90 000 plants per hm^-2 than at 82 500 plants per hm^-2, increasing by an average 3.2%~15.0%. Fv/Fm, qP, Pn and SOD activity in wide-narrow row planting mode were higher than in equidistant row planting mode, while NPQ, POD activity and MDA content exhibited the polar opposite. When the density exceeded 75 000 plants per hm^-2, Fv/Fm, qP, Pn and SOD activity in "Zhengdan 958" were higher than those in "Xundan 20", but NPQ, POD activity and MDA content exhibited the polar opposite. D1 protein content, Fv/Fm, qP, NPQ, Pn, activities of SOD and POD, MDA content, bald needle length, ear weight and yield were significantly influenced by variety, plant density and planting mode. The interactions of the three factors were distinctively significant. Yield was highest at a density of 82 500 plants per hm^-2 in the wide-narrow row planting mode for the two summer maize varieties.

Effects of different growth stage irrigations on small-grainpeanut leaf photosynthetic characteristics

DING Hong, DAI Liang-Xiang, SONG Wen-Wu, CI Dun-Wei, WU Zheng-Feng, ZHANG Zhi-Meng

2012, 20(9): 1149-1157. doi: 10.3724/SP.J.1011.2012.01149

Abstract(1367) PDF(1320)

Abstract:
This study analyzed the effects of irrigation at different growth stages on peanut leaf photosynthetic and physiological characteristics and determined the period of maximum water efficiency in peanuts. The rainproof installation pool culture method was used in the study. Two small-grain peanut varieties ("HY 20" and "HY 27") were subjected to five treatments of irrigation - irrigation during the entire growth stage (CK), drought stress during the entire growth stage (T1), irrigation at seedling stage (T2), irrigation at flower-pegging stage (T3) and irrigation at pod-setting stage (T4). Photosynthetic pigment contents and chlorophyll fluorescence parameters of different peanut varieties were comparatively analyzed. The results showed that change in leaf chlorophyll-a content of the two peanut varieties was not significant under different growth-stage irrigations. However, different treatments yielded different ranges of increase or decrease in chlorophyll-a content. Leaf carotenoid content under different soil water conditions was different for the two varieties. Also peak times for carotenoid content under drought-stress treatment were different for the two varieties. Irrigation at pod-setting stage increased chlorophyll-b and carotenoid contents. "HY 27" Fv/Fm value in the entire growth stage irrigation was higher than that of "HY 20", which meant that light energy conversion efficiency of "HY 27" was stronger than that of "HY 20". Irrigation at pod-setting stage of both varieties improved Fv/Fm and Fv/Fo values and increased light energy conversion efficiency. This was an effective way of avoiding or alleviating damage to photosynthetic apparatus. Irrigation at flower-pegging stage, pod-setting stage and in entire growth stage yielded higher apparent photosynthetic electron transport rate (ETR) and non-photochemical quenching coefficient (Q_N) values with higher retained total photosynthetic reaction. Irrigation at seedling stage of the two varieties did not increase net photosynthetic rate (Pn) at the late growth stage. In the entire growth stage under different irrigation treatments, Pn, Gs and Ci declined. This meant that stomatal limitation was the main factor for decline in peanut Pn under water-stress condition. Overall, irrigation at flower-pegging stage and pod-setting stage improved leaf photosynthetic capacity, indicating that irrigation after peanut flowering was cost-effective.

Impact simulation of drought disaster at different developmentalstages on winter wheat grain-filling and yield

ZHANG Jian-Ping, ZHAO Yan-Xia, WANG Chun-Yi, YANG Xiao-Guang, WANG Jing

2012, 20(9): 1158-1165. doi: 10.3724/SP.J.1011.2012.01158

Abstract(1327) PDF(1533)

Abstract:
Based on WOFOST crop growth model, this study analyzed the impact of different drought intensities during one, two or three combination of jointing, heading and grain-filling stages on the grain-filling and yield of winter wheat in Zhengzhou, Henan Province. The simulation results showed that when water supply was reduced by 10~30 mm during single development stage, grain-filling intensity began decreasing on 14~18 days after normal grain-filling date, which reduced yield by 1.34%~12.5%. While the highest impact on winter wheat yield was when drought occurred at heading stage and then at grain-filling stage, the lowest impact was when drought occurred at jointing stage. When water supply was reduced by 10~20 mm at two developmental stages, grain-filling intensity began decreasing on 10~17 days after normal grain-filling date, which reduced yield by 4.94%~21.88%. The highest effect on winter wheat yield was when drought occurred at both heading and grain-filling stages and then at jointing and grain-filling stages. The lowest impact was when drought occurred at both jointing and heading stages. When water supply was reduced by 5~15 mm during the three developmental stages, grain-filling intensity began decreasing on 11~16 days after normal grain-filling date, which reduced yield by 3.93%~24.84%. The above results showed that drought reduced winter wheat yield by affecting grain-filling intensity due to soil water deficit. The reduction in yield was significantly different when drought occurred at different developmental stages. There was higher impact on winter wheat when drought occurred at several developmental stages than at a single developmental stage.

Determining sprinkler technical parameters with consideration for microclimate modification effects

ZHAO Wei-Xia, LI Jiu-Sheng, LI Yan-Feng

2012, 20(9): 1166-1172. doi: 10.3724/SP.J.1011.2012.01166

Abstract(1304) PDF(1244)

Abstract:
Application intensity and time are two important parameters for the design and operation of sprinkler irrigation systems. The effects of microclimate modification from sprinkler water evaporation have not still been adequately considered in conventional methods of determining sprinkler technical parameters. This study proposed an approach to determine application intensity and time with consideration for microclimate modification effects of sprinkler irrigation using the extended CUPID model. In the model, application intensity and time parameters were determined using maximized sprinkler efficiency. Sprinkler efficiency was simulated under varying application intensities and times in summer corn seasons in Xinxiang City during 2001-2007 and in Daxing during 2005-2011. The optimal parameters for the two regions were then determined. The results indicated that sprinkler efficiency decreased with time during summer corn growth. The influence of sprinkler intensity on inter-annual variations of sprinkler efficiency differed with irrigation region. Furthermore, daytime sprinkler irrigation produced higher inter-annual variations than that nighttime sprinkler irrigation. While the optimal application intensity in Xinxiang was 10 mm·h^-1 for silt-loam soils, it was 15 mm·h^-1 in Daxing for sand-loam soils. For both Xinxiang and Daxing region, maximum sprinkler efficiency was obtained at 8:00 am.

Agricultural water-saving regionalization in Guanzhong area

YIN Jian, WANG Hui-Xiao, WANG Yan-Yang, GAO Jun

2012, 20(9): 1173-1179. doi: 10.3724/SP.J.1011.2012.01173

Abstract(1111) PDF(1122)

Abstract:
Agricultural water-saving regionalization is one of the most effective methods of promoting regional water resources utilization and alleviation of agricultural water shortage. In view of the present water resources shortage and high agricultural water consumption in Guanzhong area, studies were carried out on agricultural water-saving regionalization. Data on topography, climatic, water utilization and cropping characteristics of Guanzhong area were collected and analyzed using combined principal component analysis and the fuzzy cluster analysis methods. Based on integrated analyses of topography, climate, water utilization, social economy and cropping structure in Guanzhong area, 13 indexes (aridity, elevation, irrigation water use, farmland irrigation rate, farmer net income, total agro-output value, multi-cropping, grain-crop seeding ratio, oil-crop seeding ratio, vegetable seeding ratio, melon/fruit seeding ratio, other crops seeding ratio) were used to build a regional index system. The 13 primary indexes were selected after variation and correlation analysis of regionalization principles. Another 6 principal component indexes (with no correlation with each other) were calculated via principal component analysis to replace the primary indexes. This improved computational efficiency and research quality. The 42 counties of the Guanzhong area were divided into 6 agricultural water-saving regions using hierarchical clustering. The agricultural water-saving regions included mainstream region of Weihe River and Luohe River, mountain region at the upper reaches of Jinghe River and Weihe River, mountain region at the upper reaches of tributaries of Weihe River, plain region at river confluence reaches, plain region at the lower reaches of Luohe River, and Xi'an and its surrounding areas. This study finally mapped out primary agricultural water-saving patterns based on the characteristics of each water-saving region. The patterns included planting structure adjustment, drought-resistant crop promotion, agronomic water-saving measure development and efficient water-saving irrigation adoption. It was concluded that future studies focused on the development of detailed partitioning water-saving measures based on real field surveys and in-depth data collection.

Effects of ecological conditions on main quality traits of sweetpotato

KOU Meng, LI Qiang, TANG Zhong-Hou, WANG Xin, XIN Guo-Sheng, WU Wen-Sheng, WANG Liang-Ping, ZHANG Yun-Gang, TANG Wei, LI Xiu-Ying, MA Dai-Fu

2012, 20(9): 1180-1184. doi: 10.3724/SP.J.1011.2012.01180

Abstract(1604) PDF(1029)

Abstract:
Sweetpotato is one of the world's most important foods and industrial raw materials that is highly nutritious with a variety of beneficial ingredients. Sweetpotato chromosome is highly heterozygous with highly separable characteristics after hybridization. Furthermore, sweetpotato is a vegetatively propagated plant with stabilized traits during hybrid generation such that each line is a potential genotype. Storage root quality characteristics included the contents of total carotene, starch, reducing sugar, soluble sugar and protein. These storage traits are important indicators in measuring the consumption and processing quality of sweetpotato and are closely related with sweetpotato commodity. To study variations in storage root quality characteristics under different ecological environments and to provide a theoretical basis for screening specific cultivation areas conducive to the accumulation of certain quality traits, hybrids of "Xushu 25" and "Xu 22-5" were selected for research in four sites (Xuzhou, Jiangsu Province; Yantai, Shandong Province; Wanzhou, Chongqing City; Nanchang, Jiangxi Province) and two years (2008 and 2009). The results showed that ecological environment (E), year (Y), genetype (G), E×G and Y×G interactions had significant impacts on the contents of total carotene, starch, reducing sugar, soluble sugar and protein. Carotene showed that G×E interaction effect was larger than genotype and environmental effects. However, other quality traits showed that environmental effect was larger than genotype and G×E interaction effects. Soluble sugar and protein indicated that inter-annual effect was significantly higher than genotype or G×Y interaction effect. The remaining three quality traits indicated that G×Y interaction effect was larger than genotype or year effect. At the four experimental sites, the highest total carotene, reducing sugar and soluble sugar contents and the lowest starch content occurred at the Xuzhou site. The highest protein and lowest carotene contents occurred at Yantai site. Also the lowest protein and highest carotene contents occurred at Nanchang site. Then the lowest reducing and soluble sugar contents occurred at Wanzhou site. It was worthy to note that sweetpotato storage root protein content apparently increased with increasing latitude. For the two years, total carotene, reducing and soluble sugar contents in 2008 were higher than in 2009. Also starch and protein contents in 2008 were lower than in 2009. While the range of difference in starch and soluble sugar contents between the two years was small, that in the other traits was big. For the hundred different genotypes, coefficient of variation in total carotene content was largest, and that in starch content was smallest under different eco-sites and years.

Analysis of up-regulating genes of "Lemont" rice accession in response tolow nitrogen supply and accompanying barnyardgrass

FANG Chang-Xun, XU Tie-Cheng, HUANG Li-Kun, WANG Qing-Shui, HE Hai-Bin, LIN Wen-Xiong

2012, 20(9): 1185-1190. doi: 10.3724/SP.J.1011.2012.01185

Abstract(1154) PDF(1213)

Abstract:
Nutrient deficiency and the accompanying weeds are generally the influencing factors of rice growth. In this research, suppression subtractive hybridization (SSH) was used to investigate up-regulating genes in non-allelopathic "Lemont" rice accession respectively in response to low nitrogen condition and accompanying barnyardgrass. The results showed that genes encoding auxin-responsive protein which involved in plant growth and cell cycle regulation, NBS-LRR-like protein, catalase, metallothionein-like protein that involved in stress resistance, and protein metabolism relevant genes were up-regulated under low nitrogen condition. When rice was accompanied with barnyardgrass, genes encode NADH dehydrogenase, ATP-dependent RNA helicase and cytochrome oxidase that relative to plant growth and cell cycle regulation, RING finger family protein and two-component sensor histidine kinase relative to signal transduction, chitinase and glycosyl hydrolases relative to rice resistance were increased expression. The findings suggested that rice survived in low nitrogen supply or barnyardgrass competition by increased expression levels of various genes related with enhancement of resistance and plant growth regulation.

CO₂ and N₂O emissions in the red soils of agro-forestry (grass) systems conversed from cropland in subtropical hilly region of China

GUO Zhong-Lu, ZHENG Min-Jiao, DING Shu-Wen, LI Zhao-Xia, CAI Chong-Fa

2012, 20(9): 1191-1196. doi: 10.3724/SP.J.1011.2012.01191

Abstract(1405) PDF(1058)

Abstract:
Not much information exists on soil respiration and nitrous oxide emissions in soils under different terrestrial ecosystems in subtropical China. Field experiments were conducted in static chambers to investigate the effects of soil environmental conditions on CO₂ and N₂O fluxes from red soils under six different land use types. The investigated land use types included maize land, Amorpha fruticosa plantation, Vetiveria zizanioides plantation, A. fruticosa + maize and V. zizanioides + maize agro-forestry (grass) systems, and wasteland. Also variations in soil greenhouse gases, water, nitrogen, organic carbon, microbial biomass carbon and net nitrogen mineralization were determined. The results were as follows: 1) during maize growth season, CO₂ flux in wasteland was lower than that in A. fruticosa + maize agro-forestry system, sole maize, V. zizanioides + maize agro-grass system, A. fruticosa plantation and V. zizanioides plantation, in that order. However, no significant differences in CO₂ flux were noted among five land use types. 2) N₂O fluxes were 508 g·hm^-2·a^-1, 470 g·hm^-2·a^-1, 390 g·hm^-2·a^-1, 373 g·hm^-2·a^-1, 372 g·hm^-2·a^-1 and 285 g·hm^-2·a^-1 for A. fruticosa + maize agro-forestry system, A. fruticosa plantation, wasteland, V. zizanioides + maize agro-grass system, V. zizanioides plantation and sole maize, respectively. 3) No significant relationships existed between CO₂ fluxes and soil organic carbon, microbial biomass carbon or water content. Significant positive linear relationship was, however, observed between N₂O flux and soil mineralization. The study suggested that land conversion from cropland to agro-forestry potentially increased soil CO₂ and N₂O release. While land conversion from cropland to forestland and/or grassland potentially decreased soil CO₂ emission, it increased N₂O emission.

Soil carbon sequestration characteristics of plantations and influencing factors in Loess Hilly Semiarid Region

CUI Jing, CHEN Yun-Ming, HUANG Jia-Jian, WANG Qiong-Fang, YAO Zhi-Jie, ZHANG Fei

2012, 20(9): 1197-1203. doi: 10.3724/SP.J.1011.2012.01197

Abstract(1252) PDF(1170)

Abstract:
Using spatio-temporal substitution method, this study analyzed soil organic carbon (SOC), soil total nitrogen (STN), soil total phosphor (STP), root biomass and litter biomass of Caragana microphylla plantations of different ages. Soil carbon content change characteristics under C. microphylla plantations and the influencing factors in the Loess Hilly Semiarid Region were discussed. It threw further light on soil carbon mechanisms under C. microphylla plantations. The results suggested that at 0~60 cm soil profile, SOC content steadily decreased with soil depth increasing. Also SOC content in the 0~20 cm soil layer was higher than that in the other soil layers. At 0~20 cm soil layer, SOC content was 2.68~11.44 g·kg^-1. At 40~60 cm soil depth, however, SOC content fluctuated only minimally and was 1.64~2.73 g·kg^-1. Compared with two-year abandoned sloping farmland (CK), variations in average SOC content under C. microphylla at 0~60 cm soil depth initially decreased and then increased before finally stabilizing with time. At C. microphylla ages 10 and 17, SOC content significantly decreased by 34.5% and 26.9%, respectively, compared with that in CK. At C. microphylla age 26, SOC content significantly increased, which was 1.43 times as that in CK. At C. microphylla ages 40 and 50, however, SOC content was in the state that accumulation and consumption of SOC was relatively stable. Correlation analysis showed that SOC was significantly correlated with STN, root biomass and litter biomass. However, there was no correlation between SOC and STP contents. The results indicated that soil carbon sequestration capacity increased by increasing soil total nitrogen content. Both the amounts of root biomass and litter biomass dictated soil carbon sequestration degree.

Effects of Monochoria vaginalis on growth and yield properties of rice and its control economic threshold estimation

ZHU Wen-Da, ZHANG Hong-Jun, TU Shu-Xin, WEI Shou-Hui, LI Lin

2012, 20(9): 1204-1209. doi: 10.3724/SP.J.1011.2012.01204

Abstract(1513) PDF(1128)

Abstract:
Sheathed monochoria [Monochoria vaginalis (Burm. F.)] is a troublesome weed in rice (Oryza sativa L.) fields. Understanding damages of sheathed monochoria and economic threshold of control in rice fields could standardize sheathed monochoria control measures, promote weed control modernization and reduce herbicide pollution. A field experiment was conducted to study damages of sheathed monochoria to rice growth and yield along with economic threshold of prevention by manual weeding and herbicides use. The study set different densities (0 plant·m^-2, 1 plant·m^-2, 5 plant·m^-2, 10 plant·m^-2, 20 plant·m^-2, 40 plant·m^-2 and 80 plant·m^-2) of sheathed monochoria in rice field. The results showed that fresh biomass of sheathed monochoria at 80 plant·m^-2 was 17 t·hm^-2, with accumulated N, P, and K in weed shoots of 32.66 kg·hm^-2, 9.17 kg·hm^-2 and 58.17 kg·hm^-2, respectively. Rice was severely inhibited due to competition with sheathed monochoria for both nutrients and sun light. In comparison with the control, plant height, effective ear number and ear length of rice dropped by 20%, 46% and 11%, respectively at sheathed monochoria density of 80 plant·m^-2. However, blighted rice grain number increased by 3.5 folds, which resulted in rice yield drop by 55%. The optimum regression for rice yield loss rate (y) and sheathed monochoria density (x) was a square root model of y=8.437 1+5.024 9sqrt(x) at F=177.42 and P < 0.000 3. For 6 000~9 000 kg·hm^-2 rice yield, the sheathed monochoria economic threshold for manual weeding was 4.0~14.8 plant·m^-2. Also for 6 000~9 000 kg·hm^-2 rice yield, it was 1.0~1.6 plant·m^-2 for application of 10% Bensulfuron-methyl WP, 10% Pyrazosulfuron WP, 48% Bentazon and 56% MCPA sodium salts. The results suggested that sheathed monochoria severely inhibited rice growth and yield. Also chemical pesticides were efficient in controlling weeds based on estimated economic thresholds of control.

Effects of saline ice-melt water irrigation on soil water, salt movementand corn growth in agricultural fields

CHE Sheng-Guo, LIN Zhi-An, ZUO Yu-Bao, ZHAO Bing-Qiang

2012, 20(9): 1210-1215. doi: 10.3724/SP.J.1011.2012.01210

Abstract(1334) PDF(1164)

Abstract:
Freshwater is widely regarded as the most important and fundamental natural resource that is integral to all ecological and societal activities, including food and energy production, industrial development and human health. At the global or even country level, there exists significant spatio-temporal variability in renewable water resources, resulting in severe freshwater shortages in some regions of the world. Underground salt-water deposits could not meet domestic water supply requirements due the generally high salt content even for agricultural irrigation, let alone for domestic consumption. So desalination, which is the separation of water form salt solution for freshwater supply, could be a viable option needing facilitation. Four laboratory irrigation modes were designed in Dezhou Experiment Station of Chinese Academy of Agricultural Sciences. The irrigation modes included control treatment (freshwater irrigation, CK), saline water irrigation (SW), saline ice-melt water irrigation (MI) and saline ice-water irrigation plus wheat straw mulch (MI+SW). The mechanisms of water and salt movement in the soil during saline ice-water melt were studied in a soil column experiment. Corn was planted in the soil column after seven days and the effects of saline ice-melt water irrigation on soil water content, salt movement and corn growth determined. The results showed soil water content in the 0~40 cm layer under saline water irrigation treatment was lower and that in the deeper soil layer higher compared to that under freshwater irrigation treatment. Compared with freshwater irrigation treatment, saline ice-melt water irrigation treatment also showed a similar trend; where there was lower water content in surface soil and higher water content in deep soil layers. However, wheat straw mulching increased soil profile water content. Soil salinity under freshwater irrigation treatment was very low in the 0~60 cm soil later, less than 0.2 dS·m^-1. In the 60~80 cm soil layer, however, salinity increased significantly (0.4 dS·m^-1), although still much lower than that under saline water irrigation treatment. While saline ice-water irrigation treatment decreased salinity in the 0~40 cm soil layer, it increased salinity in deep soil layers. Salt accumulation was higher under saline water irrigation treatment with aggregation properties in surface soil. The 0~40 cm soil layer accounted for 62.2% of accumulated salt in the 0~80 cm soil layer. However, accumulated salt in the 0~40 cm was 18.6% of accumulated salt in the 0~80 cm soil layer under saline ice-water irrigation treatment. Saline ice-water irrigation plus straw mulching accelerated desalinization of soil surface, especially in the 0~10 cm soil later. Salinity under saline ice-water irrigation plus straw mulching was only 0.15 dS·m^-1 with a salt content of 67.8 g·m^-2, which showed no significant difference with freshwater irrigation treatment. This suggested gradual reduction in total salt content of melt-water. Saline ice-water irrigation improved surface soil desalination and maintained low root-zone soil salinity, which alleviated or even eliminated salinity-driven hazards in agricultural crop and soil environment. Agricultural soil conditions even improved further when saline ice-water irrigation was combined with straw mulching, under which corn graw well as under freshwater irrigation. In a conclusion, underground salt water was usable during ice-melt in the Huang-Huai-Hai Plain.

Effects of different saline-alkali land amendments on soil physicochemical properties and alfalfa growth and yield

ZHENG Pu-Shan, HAO Bao-Ping, FENG Yue-Chen, DING Yu-Chuan, LI Yi-Feng, XUE Zhi-Qiang, CAO Wei-Dong

2012, 20(9): 1216-1221. doi: 10.3724/SP.J.1011.2012.01216

Abstract(1942) PDF(1545)

Abstract:
Saline land improvement is important in offsetting contradictions between increasing population and declining soil areas. It enhances the quantity and quality of farm production, improves ecological environment and promotes regional development of sustainable agriculture. This study determined the effects of localized saline-alkali soil amendments on heavy saline-alkali soil. The experiment used alfalfa as trial crop to investigate the effects of desulfurized gypsum, Guochan-1 and Guochan-2 amendments on soil physical and chemical property and the emergence rate and fresh yield of alfalfa in waste saline-alkali soils with heavy soda. The effects of desulfurized gypsum on heavy metal contents of soils and leaves and stems of alfalfa were also investigated under field conditions. The experiment was conducted in a complete randomized design with four replicas of each treatment. Four treatments were control (without amendment), Guochan-1 (application rate of 2 250 kg·hm^-2), Guochan-2 (application rate of 7 960 kg·hm^-2) and desulfurized gypsum (application rate of 22 500 kg·hm^-2). The results showed that compared with the control, soil pH reduced by 0.11~1.46, soil density declined by 0.01~0.06 g·cm^-3 and porosity increased by 1.15%~10.15% after application of soil amendments. Furthermore, amendments improved soil perviousness and soil physical and chemical properties. Alfalfa emergence rate increased by 18.4% to 31.7%, fresh biomass of the three crops increased by 18.9%~43.5% and yield significantly increased under amendments over the control. Soil and plant Hg, Pb and Cr contents were significantly influenced by desulfurized gypsum and Guochan-2 appli-cations. Among the three amendments, Guochan-2 amendment produced the best effects regarding saline-alkali soil improvement. Whereas heavy metal content did not exceed Grade-II Soil National Standard for Agricultural Environment Quality, alfalfa Hg, Cd, Pb and Cr contents were within National Standard for Feed Qygienic Quality. This research suggested that among the three sa-line-alkali soil amendments, Guochan-2 produced the best effects. It was therefore recommended for wide application in similar sa-line-alkali soil conditions.

Optimization of cattle manure hydrolysis and acidificationfor methane production

SUN Yu, FU Bo-Rui, LIU Quan, YAN Lei, WANG Wei-Dong, WANG Yan-Jie

2012, 20(9): 1222-1229. doi: 10.3724/SP.J.1011.2012.01222

Abstract(1603) PDF(1438)

Abstract:
Although high lignocellulose content decreases acidification rate of anaerobic fermentation of cattle manure, acidification phase is critical in anaerobic fermentation of cattle manure. Cattle manure acidification conditions were investigated with the aim of optimizing methane production in a two-phased anaerobic process of cattle manure. The effects of acidification time, stirring frequency, feed solution concentration and urea addition for cattle manure methane production were studied in a two-phased anaerobic fermentation at 35 ℃. Single factor experiments showed that 96 h of acidification, 3 times in every 24 h (60 r·min^-1, 1 min·time^-1) of stirring frequency, 8.0% feed solution concentration and 1.28 g·L^-1 urea addition were the optimum conditions. Based on single factor experiments, a series of central composite design experiments were conducted for optimum synthesis. Response surface methodology (RSM) with central composite design (CCD) was used to explore optimum conditions for methane production. The effects of three variables (acidification time, feed solution concentration and urea addition) were subsequently appraised. A regression model for methane production under the acidification conditions was established for analysis of interactions and significance in accordance with central composite design. Results showed that methane production was greatly influenced by feed solution concentration, urea addition and acidification time under at 35 ℃ and 3 times per every 24 h (60 r·min^-1, 1 min·time^-1) stirring frequency. The optimum acidification conditions occurred at the acidification time of 93.7 h, feed solution concentration of 8.3% and urea addition of 1.26 g·L^-1. Under the optimum condition, methane content and total production increase by 14.3% and 44.7%. Also the removal rates of volatile solid (VS) and chemical oxygen demand (COD) increased by 41.8% and 33.9%, respectively. However, the contents of cellulose, hemicellulose and lignin were not affected by cattle manure acidification. The findings indicated that cattle manure acidification improved methane production, methane content, and VS and COD removal rates.

Determination of BTH-induced wheat resistance to Puccinia striiformis

HAN Qing-Mei, LIU Wei, WEI Guo-Rong, HUANG Li-Li, KANG Zhen-Sheng

2012, 20(9): 1230-1235. doi: 10.3724/SP.J.1011.2012.01230

Abstract(1430) PDF(1146)

Abstract:
Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most damaging wheat plant diseases across the globe. Exploration of resistant cultivars is one of the most economic and preferred control methods of stripe rust diseases. Wheat resistance to stripe rust fungi could easily be lost due to rapid virulent variations in Pst races. Benzothiadiazole (BTH), a novel and powerful elicitor, could induce systemic acquired resistance (SAR) in plants. So far no report has focused on BTH-induced wheat resistance to stripe rust fungi at maturity growth stage. Hence in this study, wheat cultivars of "Huixianhong" seedlings and "97148" mature plants were pre-treated with BTH and inoculated with Pst race CYR23. Disease index and control efficiencies evaluations indicated improvements in wheat resistance to Pst and induction of SAR by BTH. In "Huixianhong" wheat seedlings, resistance to Pst significantly increased and stripe rust disease index reduced by 29.69~49.77. Meanwhile stripe rust disease control efficiency in "Huixianhong" wheat seedlings after BTH treatment reached 90%. Optimum concentration and time interval of BTH pre-treatment tests also showed that 0.3 mmol·L^-1 of BTH concentration and 6~7 days intervals between BTH treatment and Pst inoculation were the best. Furthermore, BTH-induced wheat resistance to Pst was noted to last at least 15 days after Pst inoculation. Mature "97148" wheat cultivar sprayed with different concentrations (0.1~1.0 mmol·L^-1) of BTH showed nominal fluctuations in disease index, but with much stronger wheat resistance to Pst. Meanwhile grain yield of 0.3 mmol·L^-1 BTH-treated plants reached 675.32 kg·667m^-2, which was 19.3% higher than the control. The results also indicated that BTH sprayed at different wheat growth stages (e.g., tillering, pre-jointing and tillering/pre-jointing) had no influence on the efficiency of BTH-induced wheat resistance to Pst. Compared to the control, however, BTH treatment impacted disease index of Pst and grain yield of wheat at each different growth stage. Due to stronger seedling assays, BTH-induced wheat resistance to Pst in mature plants lasted at least 60 days. In conclusion therefore, the study demonstrated that BTH induced wheat resistance to stripe rust fungi at both seedling and maturity stages. This finding was significant in controlling stripe rust disease of wheat and other field crops.

Effects of heavy metal compound contamination of Cd, Zn, Cu andPb on soil biological activity

HAN Gui-Qi, WANG Bin, XU Wei-Hong, WANG Hui-Xian, ZHANG Hai-Bo, LIU Jun, ZHANG Ming-Zhong, ZHOU Kun, XIONG Zhi-Ting

2012, 20(9): 1236-1242. doi: 10.3724/SP.J.1011.2012.01236

Abstract(1565) PDF(1116)

Abstract:
Soil microbial indicators and enzyme activity in Dongchuan copper mining wasteland of Yunnan Province were comparatively studied in laboratory with collected field samples. Incubation experiment was also conducted to investigate the influence of combined heavy metal pollution of cadmium, copper, zinc and lead on soil microbial indicators and soil enzyme activity. The results indicated that soil organic matter, available nitrogen (N), phosphorus (P) and potassium (K), and pH significantly decreased with decreasing distance of soil sampling points from the mines. Enzyme activity, microbial quantity, microbial biomass carbon (C) and N also decreased with decreasing distance of soil sampling points from the mines. Compared to the control (10 000 m from the mines), sucrase, urease, acid phosphatase, catalase and dehydrogenase activities along with amounts of bacteria, actinomyces and fungi in collected soil samples at 0~800 m from mine decreased by 25.5%~47.3%, 22.6%~74.2%, 30.9%~83.1%, 16.7%~69.1%, 34.6%~92.3%, 30.5%~80.1%, 8.1%~49.9% and 3.3%~8.3%, respectively. Whereas microbial biomass C and N decreased by 23.7%~66.2% and 31.8%~74.7%, respectively, while microbial biomass carbon to nitrogen ratio increased with decreasing distance from the mines. Soil Organic matter, available N, P and K significantly decreased probably due to significant reductions in soil enzymatic activity, microbial amount, microbial biomass C and N. Compared with other indicators, soil phosphatase and catalase activity along with soil bacteria population were more sensitive to the degree of heavy metal pollution. Under incubation experiment at 25 ℃, soil enzyme activity, microbial population, and microbial biomass C and N were enhanced by combined pollution of low Cd, Zn, Cu and Pb. This, however, obviously decreased under combined pollution of high Cd, Zn, Cu and Pb. There were synergistic and antagonistic effects among Cd, Zn, Cu and Pb. While synergistic effects between Pb and Cd, Zn or Cu were related to microbial biomass C and N, antagonistic effects between Pb and Cd, Zn or Cu were related to bacteria population. Synergistic effects coexisted with antagonistic effects between Pb and Cd, Zn, Cu in relation to fungi and actinomyces populations, respectively.

Application of hyper-spectral remote sensing in monitoring chlorophyll-aconcentration in drinking water source reservoir in North China

HAN Li-Mei, XIAO Jie-Ying, WANG Yu-You, CUI Jian-Sheng

2012, 20(9): 1243-1247. doi: 10.3724/SP.J.1011.2012.01243

Abstract(1449) PDF(1488)

Abstract:
Remote sensing has been widely used for water quality monitoring in recent decades. Hyper-spectral remote sensing is a very effective technology for detecting large-scale water eutrophication, which has attracted lots of research in monitoring chlorophyll-a. In this paper, we used hyper-spectral remote sensing technology to present a method for monitoring chlorophyll-a concentration in Huangbizhuang Reservoir in Shijiazhuang, Hebei Province. In-situ hyper-spectral measurements were conducted by using the portable EKO MS-720 spectroradiometer at 10 different points in Huangbizhuang Reservoir, the source of drinking water for Shijiazhuang City and irrigation water for a large area of croplands along Shijin Irrigation Channel. Water samples were also simultaneously collected for laboratory analyses. Sample site position information was recorded via portable GPS. Chlorophyll-a concentration of the water samples were measured in laboratory by Acetone-spectrophotometric. The hyper-spectral data were converted into remote sensing reflectance. Then different band reflectance, reflectance ratio and other reflectance indices were designed and calculated. Linear correlation analysis between chlorophyll-a concentration and spectral reflectance, reflectance ratio and first-order differential of the water sample reflectance were also analyzed and compared. At last, the spectral reflectance ratio model and the first-order differential model were selected based on obtained correlation coefficient and significance. The results showed that Huangbizhuang Reservoir water chlorophyll-a concentration was low, with the highest concentration of 4.55 g·L^-1. It indicated that the reservoir water was in good condition. Spectral reflectance ratio model (R_705nm/R_680nm) showed close correlation with chlorophyll-a concentrations (r² = 0.736 6). On the other hand, the 696 nm first-order differential reflectance model showed a lot more significant correlation with chlorophyll-a concentrations in the entire analytical tests (r² = 0.875 5). This illustrated that the 696 nm first-order differential reflectance model was more effective for chlorophyll-a concentration monitoring in Huangbizhuang Reservoir. Through linear regression estimation, chlorophyll-a concentration in Huangbizhuang Reservoir was generally at the state of oligotrophication. Hence with regard to chlorophyll-a concentration, Huangbizhuang Reservoir water was suitable for domestic, industrial and irrigation use. The method proposed in this work had potential applications in environmental management for improved chlorophyll-a concentration monitoring efficiency in large-scale water bodies. It was also applicable in policy/decision- makings needed for early warning and prevention of water eutrophication.

Measurement of transaction cost of rest-grazing policy

FAN Sheng-Yue, XU Yu-Cai, DUAN Shuang-Quan, LAN Jian, XU Jun

2012, 20(9): 1248-1253. doi: 10.3724/SP.J.1011.2012.01248

Abstract(1147) PDF(1124)

Abstract:
A package of juristictive and administrative measures for conserving rest-grazing meadow ecosystems has been developed by various organs of government. Although much research has already been done in this area, it was still worthwhile and absolutely essential to assess the performance efficacy of existing measures on rest-grazing meadow ecosystems. This article attempted to probe into the assessment approach of existing measures about ecosystem governance, inherent interactions between jurisdictive/administrative measures and ecological protection, and the reason why unique measures have different efficacies. We studied existing measures that governed deserted meadows and introduced transaction-cost analysis approaches. In the study, transaction cost was identified in five parts-information search cost, contract signing cost, governance and operation cost, compliance and supervision cost, and compensation and remedy cost. Distinguished indicators were developed for each part based on the key nodes upon which the measures were conducted in the area and hence a total of 21 indicators were used. For Uxin Banner of Inner Mongolia Autonomous Region, the total transaction cost was 906.05 Yuan·hm^-2 per year according to investigation data. From this amount, 116.48 Yuan·hm^-2 (12.86% of total transaction cost) was directly paid as compensatory fee by government to herder households. Then herder households in turn paid 728.02 Yuan·hm^-2 (80.35% of total transaction cost) per year. Rather than government, the main investor in rest-grazing ecosystems was demonstratively herder households. On the other hand, direct government payment or opportunity cost of rest-grazing ecosystems was only 23.3%. Consequently, herder household interests were weakened, increasing stolen grazing rate in rest-grazing ecosystems to 100%. Measures of rest-grazing were therefore meaningless as long as government direct payments remained lower than 1/4 of the opportunity cost of rest-grazing ecosystems. Transaction cost analysis of jurisdictive and/or administrative measures addressing ecosystem problems provided monitoring and assessment perspectives to conservation measures of meadow ecosystems.

Willingness to pay for ecosystem services and influencing factors inWeigan River Basin

QIAO Xu-Ning, YANG Yong-Ju, YANG De-Gang

2012, 20(9): 1254-1261. doi: 10.3724/SP.J.1011.2012.01254

Abstract(1444) PDF(1177)

Abstract:
Ecosystem service value (ESV) calculation is a focus of ecological economics and is key in ecological compensation. Contingent valuation method (CVM) was used to measure ecosystem service value in Weigan River Basin, one of nine branches of Tarim River Basin and the largest inland river in arid China, in terms of the willingness to pay (WTP). Pearson correlation coefficients and multiple linear regressions were used to analyze relations between socio-economic variables and WTP. The results indicated that: 1) mean value of WTP for ecosystem services in Weigan River Basin was 96.22 Yuan per household per annum. While this was lower than that in river basins in East China and other countries, it was close to that in river basins in Northwest China. Residents' chosen WTP was 110.87~157.58 Yuan and 55.8~102.37 Yuan per household per annum in the up and down stream regions of the basin, respectively. Total annual value of ecosystem services in the basin was 24.43 million Yuan. 2) Residents' chosen WTP was positively correlated with income level, education level, household registration and cognitive level of importance of ecological environment. It was, however, negatively correlated with payment. Gender and age did not obvious influence residents' chosen WTP. Residents' chosen WTP in towns was higher than that in rural area, but not in upstream. Relationship between WTP and the influencing factors was different for upstream and downstream regions. 3) The most critical WTP factor was income level (with a standardized coefficient of 0.604), followed by household cognitive level, payment and the education level. Effective options were advanced to improve watershed residents' WTP, including addressing poverty of local residents, strengthening publicity of the importance of ecological environment, enhancing residents' education level and selecting appropriate payments that took into account residents with different household registrations and regions. 4) CVM results were similar for similar regions, and consistent with the results obtained by remote sensing methods. Ecosystem service values calculated by different methods were different in the same basin. The study presented problems and solutions of multiple co-linearity analysis in multiple regressions. The study enriched CVM application in minority areas in arid inland river basins. The results were important justification for appropriate adjustments in payments for ecological services.

2012 Vol. 20, No. 9