中国生态农业学报(中英文)

Effects of fungicide application and heterogeneous fertilization on the growth and yield of maize and potato

LI Yongxian, ZHANG Xiaoyun, ZHANG Leilei, LI Wang, WU Kaixian

2018, 26(6): 791-798. doi: 10.13930/j.cnki.cjea.170891

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Abstract:
In agriculture, fertilizer and fungicide applications are critical for high yield. For the fertilization, it is known that block and strip fertilizations are common practices. These methods can result in the formation of pockets of soil nutrients. In this case, the orientation of root growth towards soil nutrients is important for absorbing heterogeneous nutrients. Fungicides can permeate into the soil through leaching, which directly or indirectly affects soil environment and root-soil interaction. However, it is not clear if soil micro-organisms change caused by fungicides adding affects crop root growth orientation and yield. A field experiment was conducted in 2015 and 2016, in which maize and potato were planted to explore the effects of fungicides adding and nutrient patches on crop growth and yield. We first generated soil nutrient patch by interlaced fertilization. Then broad-spectrum fungicides were applied through watering. Next, crop yield, shoot biomass, root biomass and root foraging precision were measured. The two-year field experiment demonstrated that watering fungicides and nutrient patches significantly affected plant biomass, yield, root biomass and root growth orientation. Importantly, we observed significant positive interaction between fungicides and nutrient patches. The significant increase in maize plant biomass was due to the application of fungicides under heterogeneous fertilization. Also the significant increase in maize plant biomass was promoted by nutrient patches after fungicide application. Besides, the results suggested that the application of fungicide benefited the adaptation of crops to heterogeneous fertilization. This was because that root foraging precision of maize and potato was promoted by the application of fungicides. Moreover, there was significant increase in root foraging precision of potato. However, the effect of fungicide and nutrient patches on plant growth was significantly affected by the complex interaction between crop type and planting year. Therefore, further studies were necessary to explore the role of fungicides in adaption of crops to nutrient patches and the mechanisms of growth orientation of roots towards soil nutrients. Such study should be based on various crops, ecological environments and cultivation practices, increasing the potential for in-depth understanding of the effects of pesticides on the use of chemical fertilizers.

Effect of nitrogen application rate on root soy isoflavone exudate of wheat/faba bean intercropping system

LIU Yingchao, XIAO Jingxiu, TANG Li, ZHENG Yi

2018, 26(6): 799-806. doi: 10.13930/j.cnki.cjea.170901

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Abstract:
Through pot and hydroponics experiments of wheat/faba-bean, mono-cropped faba-bean and mono-cropped wheat, soy isoflavone exudate of faba-bean and wheat were studied under different nitrogen (deficient, adequate and excessive) conditions at different growth stages. The study aimed at providing the basis for further understanding of yield increase and disease control mechanisms of intercropping systems. The results showed that with the growth of crops, soy isoflavone exudate of wheat roots decreased, while that of faba-bean first increased before decreased. With the increase of nitrogen application rate, soy isoflavone exudate of both wheat and faba-bean decreased, and most changes were significant. Compared with deficient nitrogen treatment, soy isoflavone exudates of intercropped wheat were increased respectively by 18.9% and 122.1% at stem elongation stage (60 d after sowing) under adequate and excessive nitrogen conditions. Accordingly, soy isoflavone exudate of mono-cropped wheat was increased by 28.9% and 72.7% under adequate and excessive nitrogen conditions. Crops intercropping increased soy isolavone secretion of crops, which was significant only at lower nitrogen level. Compared with mono-cropped wheat under deficient and adequate nitrogen condition at stem elongation stage of wheat (60 d after sowing), soy isoflavone exudate of intercropped wheat was significantly increased by 26.9% and 12.0%, respectively, in pot experiment, and 15.3% and 59.2% in hydroponics. Compared with mono-cropped faba-bean under deficit and adequate nitrogen rates at branching stage (60 d after sowing), root soy isoflavone secretion of intercropped faba-bean was significantly increased by 64.6%, and 11.4% in pot experiment, and 23.8% and 14.1% in hydroponics experiment, respectively. At flowering and filling stages of wheat, and flowering and pod-bearing stages of faba-bean, the similar tendency was observed. In short, both intercropping and nitrogen fertilization changed root secretion of soy isoflavone by wheat and faba-bean, which was more obvious under lower nitrogen application rate.

Effects of nitrogen fertilizer reduction on root exudates of maize seedling ana-lyzed by rhizosphere metabonomics

PENG Yujie, CHENG Nan, LI Jiajia, KONG Yanglu, SUN Caixia

2018, 26(6): 807-814. doi: 10.13930/j.cnki.cjea.170858

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Abstract:
As one of the most critical environmental factors driving plant growth, soil N availability significantly influences the composition and quantity of root exudates. Concerning the environmental benefits, the inputs reduction of N fertilizer can be an attractive option for crop production in a more sustainable agriculture system. However, the pattern of root exudates in response to the reduced N levels remains poorly understood, especially for maize (Zea mays L.) plants. Metabolomics of root exudates can potentially help us to better understand the chemical communication between roots, soils and organisms in the rhizosphere. In this study, to characterize root exudation pattern of maize plants grown under conditions with reduced N fertilizer at metabolomics level, three methods were developed for collecting root exudates from maize seedling planted in soils through soil leachate (SL), rhizosheath soil extraction (RS) and distilled water cultivation (DWC), respectively. The metabolomics of root exudates collected by different methods under nitrogen fertilizer reduction conditions were investigated based on ¹H NMR spectroscopy. Partial least squares projection to latent structures-discriminant analysis was performed to quantify the difference of metabolomics among samples and conditions. The results showed that the whole profilings of ¹H NMR were distinctly different among root exudates obtained by three methods, and the major compounds contributing to the discrimination also varied. The most important exudates that differentiated the samples between SL and RS methods were glucose and alanine while more exudates such as acetate, lactate, succinate, sucrose, alanine, leucine, isoleucine and valine accounted for the discrimination between SL and DWC methods. In addition, the most important exudates that differentiated the samples between RS and DWC methods were acetate, lactate, succinate and isoleucine. The peak signals of ¹H NMR and number of assigned metabolites in root exudates detected by method of SL were less while that were rather more in the methods of RS and DWC; and sugars, organic acids and amino acids in root exudates of maize seedlings were detected by the latter two methods. In contrast to the control of 100%-N level (corresponding to the conventional application rate of 180 kg·hm^-2), the levels of α-glucose, malate, leucine and valine increased significantly in root exudates of maize seedlings in treatment with 85%-N level. However, the level of exudates decreased with reducing fertilizer N application rate and its difference between control and 55%-N treatment was not significant. The changes of root exudates may influence soil organic matter turnover and lead to an increase in plant-available N. Our results indicated that maize seedlings might adapt to the variation of nitrogen nutrient situation in soil by regulation of exudation. Metabolomics analysis of root exudates based on ¹H NMR spectroscopy combined with sample collecting methods of rhizosheath soil extraction and distilled water cultivation could provide important theoretical basis for the study on the rhizosphere ecology and nitrogen nutrition. The possible ecological roles of root exudates in response to N reduction should be fully elucidated in the future. A combined approach involving different metabolomic tools will facilitate the understanding of belowground chemical communications and rhizosphere interactions under conditions of N reduction.

Effect of fertilizer management on dry matter accumulation, yield and fertilizer use efficiency of rice cultivar 'Huayou-14'

SHA Zhimin, CHEN Xiahua, ZHAO Zheng, SHI Chaochao, YUAN Yongkun, CAO Linkui

2018, 26(6): 815-823. doi: 10.13930/j.cnki.cjea.171029

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Abstract:
Rice is one of the most important crops in China. The production of rice has dramatically increased over the last 50 years due to high input of chemical fertilizers. To control the unreasonable application of fertilizers (e.g., more chemical fertilizers, less organic manure or neglect of crop growth curve), we researched the effects of fertilizer application on dry matter accumulation and yield of rice in Shanghai. The objective of the study was to explore a scientific fertilization management for high yield and high fertilizer use efficiency cultivation of rice in Shanghai. To this end, two-year (2014-2015) field Lysimeter experiment was conducted at a typical paddy rice plot in a rural suburb of Shanghai, China. The 'Huayou-14' rice cultivar, which is widely cultivated in Shanghai, was used in the experiment. A total of four treatments were investigated, including no fertilizer treatment (CK) as the control, receiving neither chemical fertilizer nor manure; sole chemical fertilizer treatment (CT) of 300 kg(N)·hm^-2 urea, 60 kg(P₂O₅)·hm^-2 calcium superphosphate and 60 kg(K₂O)·hm^-2 potassium chloride applied according to the practice of local famers in the area; sole organic fertilizer treatment (OT) of poultry manure with total N at the same rate of 300 kg(N)·hm^-2; and chemical-organic fertilizers mixture (MT) of 80% urea and 20% organic manure based on 300 kg(N)·hm^-2. The dry matter accumulation characteristics, yield, fertilizer utilization rate and profitability were analyzed for different fertilization treatments. The effects of different fertilization treatments on dry matter accumulation of rice became significant from booting stage, which was higher in MT and CT than in OT and CK. Dry matter accumulation curves of 'Huayou-14' during growth stage were simulated by Logistic equation Y=W_m/(1+ae^-bt), in which t is the days after transplanting, Y is the dry matter accumulation, W_m is the ultimate amount of dry matter. The maximum dry matter accumulation rate under MT increased respectively by 0.17 kg·hm^-2·d^-1 and 0.19 kg·hm^-2·d^-1 compared with OT and CK, but no significant difference compared with CT. Photosynthate accumulation at grain filling stage contributed mainly to rice yield. The contribution rate of photosynthate accumulation at grain filling stage to yield under MT was 76.3%, which was 9.4% and 5.2% higher than that under OT and CK, but had no significant difference from that under CT. At harvest, rice yield increased respectively by 15.6% and 63.4% under MT compared with OT and CK. However, no significant difference was observed between MT and CT. Agronomic efficiency of fertilizer significantly improved under MT, which was respectively 9.7% and 53.7% higher than CT and OT. It was possible to improve yield by increasing dry matter accumulation and extending growth period. The combined application of chemical fertilizer and manure was effective for dry matter accumulation as it provided sufficient nutrient supply for growth and dry matter accumulation even after flowering. Thus, it was a useful strategy for improving rice yield, reducing chemical fertilizer input and avoiding excessive waste of resources.

Effect of tillage mode on soil structure characteristics of plough layer and sug-arcane yield

LUO Jun, LIN Zhaoli, QUE Youxiong, ZHANG Hua, LI Shiyan, LUO Hui, ZHANG Caifang, CHEN Jianfeng

2018, 26(6): 824-836. doi: 10.13930/j.cnki.cjea.170918

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Abstract:
In order to establish the mechanical deep-ploughing technology of sugarcane for formation of good plough layer soil structure, the effect of tillage modes on soil plough layer structure and yield components of sugarcane were investigated. An experiment with 3 tillage measures under two planting rows of sugarcane were conducted. The two planting rows were 1.4 m and 1.6 m, respectively, while the subsidiary treatments included three tillage modes as follows-25 cm rotary tillage (as control), 35 cm sub-soiling plus 25 cm rotary tillage (sub-soiling), 50 cm deep plowing plus 25 rotary tillage (deep plowing). Sugarcane yield characteristics, together with soil bulk density, compactness, porosity, three-phase volumetric rate, field water holding capacity, penetration resistance and shear strength were investigated. The results demonstrated that stem yield of 1.6 m rows spacing was significantly lower than that of 1.4 m rows spacing. Also soil compactness of 1.6 m rows spacing was remarkably lower than that of 1.4 m rows spacing. Soil bulk density of 1.6 m rows spacing was strikingly higher than that of 1.4 m rows spacing. The results also indicated that 1.6 m rows spacing significantly improved penetration resistance and shear strength of soil. Also both the sub-soiling and deep plowing significantly increased sugarcane yield. Compared with the control, the sub-soiling and deep plowing treatments increased soil tillage layer depth, and also improved soil com-pactness and bulk density along with the overall porosity of plough layer. It also showed that sub-soiling dramatically increased total porosity of plough layer soil especially capillary porosity of soil. Field water holding capacity of deep soil also greatly improved by sub-soiling, which finally significantly enhanced plant height elongation and stem diameter thickening at the middle and late growth stages of sugarcane. Also both sub-soiling and deep plowing significantly decreased soil penetration resistance, but with insignificant effect on soil shear strength. Among the three tillage measures, there was no significant difference in volume rate of the liquid phase. However, sub-soiling had the smallest solid volume rate and the largest gas phase volume rate. Then the control resulted in the largest solid volume rate, but the smallest gas phase volume rate. In conclusion, sub-soiling and deep plowing had positive effects on soil physical structure and significantly increased yield of sugarcane. We also concluded that in sugarcane planting areas where large horsepower tractors and high quality loosen machines were used, 35 cm sub-soiling + 25 cm rotary tillage method was the most suitable tillage mode. However, in areas without large horsepower tractors and high quality sub-soiling devices, thick plough layer was maintained by the use of 50 cm deep plowing + 25 cm rotary tillage measure.

Effects of sowing date and cultivar on grain yield and water use efficiency of spring maize in the North China Plain

SUN Hongyong, LIU Xiaojing, WANG Jintao, DONG Xinliang, GUO Kai, JU Zhaoqiang

2018, 26(6): 837-846. doi: 10.13930/j.cnki.cjea.170786

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Abstract:
The double winter wheat and summer maize rotation cropping system in the North China Plain (NCP) is mainly limited by water shortage. To solve this problem, a land fallow policy has been introduced in NCP, especially in the groundwater-over-exploited region. A three cropping system in two years which includes winter wheat, summer maize and spring maize was introduced in place of the double cropping system in a year. Meanwhile, grain yield of spring maize is mainly limited by environmental (e.g., precipitation and temperature), biological (e.g., released cultivar) factors. Improving spring maize yield and water use efficiency using optimal sowing date that is adapted to maize cultivar characteristics is critical in solving this problem. A field experiment was conducted in Nanpi Eco-agricultural Station of Chinese Academy of Science in 2016, consisting of 5 maize cultivars (HN887, HX338, ZD958, HN866 and LC1) and 3 sowing dates (May 1, May 15 and May 30) treatments. The phenological stages were observed, and soil water content in the 2 m soil profile, grain yield and yield components were measured and weather factors recorded for the period of study. The results showed that the days from sowing to maturity of the 5 cultivars all significantly reduced with sowing date delay, which mainly reduced the days from sowing to tasselling stage (P < 0.05). For different cultivars, the days from sowing to maturity were significantly different and the differences were similar (5-7 d distance) for all three sowing date treatments. There was no significant difference between averaged grain yield for 5 cultivars for May 1 and May 15 sowing date treatments. May 30 sowing date had the highest grain yield, which was mainly caused by the higher 100-grain weight (3.3 g higher than others). For water consumption, there was no significant difference among 3 sowing dates because there was no irrigation during the growth stage for all treatments and precipitation was 405.2-416.0 mm. There was also no significant difference in water consumption among different maize cultivars. The trend in water use efficiency (WUE) was also similar to that in grain yield, which increased with sowing date delay. There were significant differences in WUE among different sowing dates and maize cultivars. Meanwhile, the correlation was significant between 100-grain weight and precipitation before and after tasselling and then between 100-grain weight and accumulated temperature before and after tasselling. The comprehensive analysis of the grain yield, water uptake and water use efficiency showed that the optimal sowing date was May 30, with 'HN866' and 'HN887' as the cultivars with the best performance in the study area.

Effect of wheat straw retention on light energy utilization and water production benefits of maize in inland irrigated region

GUO Yao, CHEN Guiping, YIN Wen, FENG Fuxue, ZHAO Cai, YU Aizhong, CHAI Qiang

2018, 26(6): 847-855. doi: 10.13930/j.cnki.cjea.171115

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Abstract:
The response of light energy utilization and production benefit of crops to straw return to soils usually is important for establishing highly efficient cropping systems and optimizing cultivation practices. It is also the theoretical basis for exploring the cost-saving and benefits-increasing crop production in arid inland irrigation area. A field experiment was carried out in a typically irrigated oasis region in 2009-2012 in the Hexi Corridor of China to determine the effects on light energy utilization and production benefit of maize of different treatments of wheat straw return to soil and different tillage operations. The tillage and wheat straw retention operations included (i) no tillage with straw standing (NTSS), in which no tillage was combined with 25 to 30 cm high wheat straw standing in the field after wheat harvesting in the previous fall; (ii) no tillage with straw covering (NTS), in which no tillage was combined with 25 to 30 cm long wheat straw evenly spread on the soil surface at wheat harvest in the previous fall; (iii) tillage with straw incorporation (TIS), in which 25 to 30 cm long wheat straw was incorporated into the soil through conventional deep tillage (30 cm) at wheat harvest in the previous fall; and (iv) conventional deep tillage without wheat straw retention (as control), in which conventional deep (30 cm) plow was done with wheat straw removed from the field. The results showed that compared with the control, wheat straw retention treatments reduced leaf area duration (LAI-D) of maize before the large bell mouth stage, however, increased LAI-D of maize after silking, which effectively delayed senescence. No tillage with straw standing and straw covering (NTSS and NTS) had the best effects on senescence delay among all treatments, and the total LAI-D increased by 11.2% to 14.5% under NTSS, 16.3% to 20.8% under NTS and 6.0% to 7.5% under TIS, respectively; specifically, the increase in LAI-D under NTS treatment was the highest. Wheat straw retention had the effect of improving light use efficiency of maize field, and NTS treatment had the highest increasing effect, whose light use efficiency was 5.3% to 11.8% higher than that of the control. The previous wheat straw retention was favorable to increase grain yield of maize, and NTS treatment had the best increasing effect of grain yield, boosted grain yield by 13.7% to 17.5% compared with the control. NTSS and NTS treatments reduced the production cost, while improved the net return and the input-output ratio. NTS treatment had the large increasing range, increased the net return and the input-output ratio by 22.2% to 35.5% (3 953 to 5 200 ￥·hm^-2) and 16.8% to 23.4%, respectively. Meanwhile, the water productivity and benefit per cubic meter water were improved by 13.7% to 17.5% and 25.6% to 33.1%, respectively. Based on the results therefore, no tillage with 25 cm to 30 cm long wheat straw covering over soil surface (NTS) was the most suitable straw return strategy, which can be used as the key technology for cost-saving and benefits-increasing maize production in arid inland irrigation area.

Effects of green manure rotation on soil properties and yield and quality of silage maize in saline-alkali soils

GUO Yaodong, CHENG Man, ZHAO Xiufeng, HAO Baoping, ZHANG Yanfang, CAO Weidong, ZHENG Pushan

2018, 26(6): 856-864. doi: 10.13930/j.cnki.cjea.170952

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Abstract:
Saline-alkali lands are widespread in Datong Basin, Shanxi Province. For years, little manure has been used to improve the saline-alkali soils in the region. The barren soil and harsh ecological environment have resulted in a very low production efficiency of agriculture. Green manure has not only been an important part of modern agriculture, but also been traditionally used in agriculture in China for improvement of soil quality. In order to explore the effects of plantation and incorporation of green manure in saline-alkali soil management, a field experiment was conducted to explore the effects of green manure crops in middle level saline-alkali lands on soil physic-chemical properties, maize silage yield and protein content. Soil water content, pH, EC, nitrogen, available nitrogen, available phosphorus and available potassium were analyzed. Six types of green manure (Vicia villosa Roth., Sesbania cannabina Poir., Melilotus officinalis L., Medicago sativa L., Vicia sativa L. and Lolium perenne L.) were used in the study. Results showed that compared with the control (no green manure plantation), soil water content increased by 1.0%-6.2% during the middle and later growth periods of green manure, whereas soil pH and EC decreased by 0.03-0.43 mS·cm^-1 and 0.12-1.50 mS·cm^-1, respectively. Incorporation of green manure led to the return of 15.6-195.4 kg(N)·hm^-2, 5.3-58.8 kg(P₂O₅)·hm^-2 and 34.5-127.9 kg(K₂O)·hm^-2 to soil. With overturning of green manure, soil organic matter, total nitrogen, alkali-hydrolyzed nitrogen, available phosphorus and available potassium contents in the 0-20 cm soil layer increased by 0.42-1.86 g·kg^-1, 0.05-0.34 g·kg^-1, 0.5-32.3 mg·kg^-1, 0.42-4.65 mg·kg^-1 and 3.8-26.1 mg·kg^-1, respectively. The yield and protein content of silage maize increased by 1 294-19 391 kg·hm^-2 and 0.4-23.9 mg·g^-1, respectively. Compared with L. perenne, V. villosa and M. suaveolens increased soil water content respectively by 1.2%-5.2% and 1.0%-5.0% during the middle and later growth periods, whereas decreased soil pH by 0.06-1.30 and 0.06-1.27 and EC by 0.08-0.51 mS·cm^-1 and 0.08-0.47 mS·cm^-1, respectively. Overturning of V. villosa and M. suaveolens respectively returned 179.8 kg(N)·hm^-2 and 150.3 kg(N)·hm^-2, 40.9 kg(P₂O₅)·hm^-2 and 36.2 kg(P₂O₅)·hm^-2, and 65.0 kg(K₂O)·hm^-2 and 93.4 kg(K₂O)·hm^-2 to the soil. The yield of silage maize increased respectively by 18 097 kg·hm^-2 and 14 903 kg·hm^-2 with overturning of V. villosa and M. suaveolens, and protein content increased respectively by 23.5 mg·g^-1 and 19.2 mg·g^-1, compared with overturning of L. perenne. In general, the cultivation of legume green manures was better than graminaceous green manure (L. perenne) in decreasing soil pH, keeping soil water content, returning N, P₂O₅ and K₂O to soil and enhancing soil organic matter. Among the green manures used, V. villosa was the most effective, followed by M. suaveolens. In short, the approach of "planting and incorporating green manure and then rotation" was applicable in similar saline-alkali soil conditions. The planting and incorporation of green manure economically, effectively and environmentally improved medium saline lands, enhanced soil fertility and returned nutrient to soil.

Analysis of spatial and temporal variation in potential summer maize yield and its response to climate change in the North China Plain

JIANG Mingnuo, LIU Chaoshun, GAO Wei

2018, 26(6): 865-876. doi: 10.13930/j.cnki.cjea.170806

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Abstract:
The North China Plain is a major food producing region in China and climate change could have beneficial or unbeneficial effects on food production in the region. To accurately assess the effect of climate change on potential yield of summer maize in different regions in the North China Plain, we simulated the growth of summer maize in the plain for the period 1979-2015 using regional implementation crop growth model WOFOST (WOrld FOod STudy). We also used China Meteorological Forcing Data (form the Institute of Tibetan Plateau Research of Chinese Academy of Science) as weather data input for the crop growth model. To analyze the spatial and temporal variations in potential summer maize yield in the North China Plain, simple linear regression and empirical orthogonal decomposition (EOF) methods were applied. Using grid-by-grid correlation analysis and singular value decomposition (SVD) methods, we analyzed the correlations between potential summer maize yield and temperature and the correlations between the potential summer maize yield and total daily solar radiation during the whole growth period, pre-silking stage and post-silking stage of maize. The results showed that potential summer maize yield generally increased from south to north in the range of 7 000-9 000 kg·hm^-2. While potential summer maize yield in the northwest part of the study area was more volatile, yield fluctuation was small in southern Beijing, Tianjin and central Hebei Province, with standard deviation less than 500 kg·hm^-2. Potential summer maize yield in northern Tangshan of Hebei Province, northwestern part of the study area and the eastern part of Shandong Peninsula had a fluctuating increasing trend for the study period, with a range of 200-600 kg·hm^-2·(10a)^-1 in most of these regions. Potential summer maize yield in the rest of the study area decreased, especially in central and southern Hebei Province, Tianjin, northwestern Shandong Province, northern Anhui Province, which was around 250 kg·hm^-2·(10a)^-1. Potential summer maize yield in western and northeastern parts of Hebei Province, northwestern part of Beijing and central and eastern parts of Shandong Province had a significant positive correlation (R=0.9) with temperature. Summer maize yield in these areas had increased over the past 37 years. The analysis suggested that the increase in summer maize yield in those places were driven by rising temperatures. Potential yield in southern and eastern parts of Beijing, Tianjin, central and southern parts of Hebei Province, southern parts of Tangshan and Qinhuangdao of Hebei Province, Shandong Province, eastern part of Henan Province, northern part of Anhui Province and northern part of Jiangsu Province had a significant positive correlation (R=0.8) with total solar radiation. At the same time, the shaded area of 99% confidence level (based on Student's t-test) for the post-silking stage was larger than that for the pre-silking stage. Also the correlation coefficients were more significant for the post-silking stage. Potential summer maize yield in most of these regions was on the decline, which was caused by the decline in total solar radiation in the regions. Furthermore, total radiation reduction mainly influenced the reproductive stage of summer maize. In conclusion, increase in temperature was the main factor driving the increase in potential summer maize yield. Also the decreasing total solar radiation was the main factor driving the decrease in potential summer yield in the North China Plain.

Effect of engineering treatment on the physical and chemical properties of livestock slurry

SHENG Jing, ZHOU Wei, WANG Zichen, ZHANG Liping, SUN Guofeng

2018, 26(6): 877-883. doi: 10.13930/j.cnki.cjea.171010

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Abstract:
The combination of livestock breeding and crops planting is an important strategy for manure utilization and management. Under intensive production, the combination of livestock breeding and crops planting mainly relies on efficient modern engineering measures. However, limited studies have been carried out on the effects of engineering measures on the physic-chemical properties of slurry, which restricts the utilization of slurry as a resource. This paper reviewed recent literatures and analyzed the effects of three engineering measures (manure solid-liquid separation, anaerobic fermentation and storage) on the physic-chemical properties of slurry. The results showed that the number and size of particles, the concentration and morphology of nutrients and heavy metals in slurry changed significantly under intervention of engineering measures. In solid-liquid separation process, almost all large particles in slurry were removed and dry matter (DM), total N (TN) and total P (TP) also significantly reduced, with respective removal efficiencies of 5.7%-65% for DM, 2.7%-49% TN and 2.3%-82% for TP. Removal efficiency of DM, TN and TP as well as the rate N:P:K in slurry significantly varied with solid-liquid separation method. However, few heavy metals such as Cu and Zn were removed in solid-liquid separation process. Small particles decomposition mainly occurred in anaerobic fermentation process, which greatly reduced DM concentration in slurry. After anaerobic fermentation, the total amounts of TN and K changed little, while NH₄⁺-N concentration increased significantly with proportion of TN in the range of 46%-93%. Patches of P, Cu and Zn crystals were attached on the inside walls of the tank, while the remains transferred from liquid to solid in the anaerobic fermentation process. In the storage process, the concentrations of DM, TN, NH₄⁺-N, TP and K significantly decreased in the liquid part of the slurry, due to the decomposition and deposition. After 90 days of storage at 20-25℃, TN, TP and K concentrations in biogas slurry decreased respectively by 39%-77%, 61%-78% and 23%-54%. The study provided relevant guide on designing slurry treatment engineering and formulating comprehensive nutrient management plans in a given region. Since the area of farmland under slurry application is limited in China, livestock manure treatment usually follows multi-stage treatment technology. However, most of the current studies have focused on single engineering measure for the physic-chemical properties of slurry. Thus, it is difficult to put forward the best manure treatment scheme and treatment combination through such data. It was recommended that future works of slurry utilization in farmlands focused on:(1) the monitoring and evaluation of the response of physic-chemical properties of slurry to the entire processes of engineering treatments; (2) the development of directional regulation technology of slurry nutrient between solid and liquid phases for better application of slurry in farmlands.

Effects of Pseudomonas aeruginosa on the growth and cadmium accumulation in rice (Oryza sativa L.) seedling under Cd stress

HE Xiaosan, WANG Wei, XIAO Qingtie, ZHENG Xinyu, ZHENG Meiqin, ZHU Jingjing, HAN Yongming, WANG Dunfei, LIN Ruiyu, LIN Wenxiong

2018, 26(6): 884-891. doi: 10.13930/j.cnki.cjea.170948

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Abstract:
Heavy metal contamination in rice is a serious problem focused by people all over the world. Microbial passivation is considered as one of effective measures to inhibit heavy metal from environmental into the biological cycle. To investigate the mitigative effects of Pseudomonas aeruginosa on rice seedling exposed to cadmium stress conditions, a set of hydroponic experiments by adding 20 μmol·L^-1 cadmium solution were conducted, and the treatment without added cadmium was used as control (CK). The effects of different treatments on plant growth, cadmium content and cadmium accumulation of rice were determined. The treatments included adding with different volume of bacteria suspension, bacterial carrier A (diatomite, size 1-3 mm), carrier B (diatomite, size 3-6 mm), carrier C (activated carbon, specific surface area 1 000 m²·g^-1) and microbial inoculum A, B and C, which prepared by carrier A, B and C saturated with bacteria suspension, respectively. The results showed that the growth of root length, plant height and biomass of rice were significantly inhibited by treating with 20 μmol·L^-1 cadmium. But, the growth of rice was promoted by adding with P. aeruginosa suspension and microbial inoculum A, B and C. In contrast to the treatment only with cadmium (0.523 g·plant^-1), total biomass of rice increased by 38.5% to 67.3%, and the highest value was tested in the treatment with inoculum B. Cadmium contents in root, stem-sheath, leaf, as well as in the above parts of rice reduced in all above treatments. Under the treatments of microbial inoculum A, B, C and activated carbon, cadmium contents in above parts of rice significantly declined by 45.9%, 47.9%, 59.9% and 59.9%, the transportation factors decreased by 16.7%, 25.0%, 33.3% and 33.3%, as well the bio-concentration factors reduced by 48.1%, 48.8%, 58.8% and 60.9%, respectively. In addition, the cadmium accumulated in rice seedling reduced by 19.2%, 9.5% and 24.3% under the treatments with activated carbon, microbial inoculum A and inoculum C, respectively. While, cadmium accumulation increased by 15.0%, 30.4%, 14.8% and 16.8% under the treatments with microbial inoculum B, bacteria suspension A, B and C, which contained 56.4 mL, 45.3 mL and 28.4 mL bacteria, respectively. It meant that the bacteria promote cadmium accumulation in rice by enlarging biomass of rice. In conclusion, P. aeruginosa exhibited the capacities of promoting rice growth, reducing cadmium content, inhibiting cadmium transportation, as well as cadmium availability of rice under cadmium stress conditions. Higher cadmium passivation abilities of microbial inoculum A, B and C in this study offer us a new promising microbial strain for bio-remediation of environmental cadmium pollution.

Synergies and trade-offs of agro-ecosystem in dry-farming areas in Northeast China

ZHUO Zhiqing, XING An, SUN Zhongxiang, HUANG Yuanfang, CAO Meng, LI Zhen, ZHANG Shiwen

2018, 26(6): 892-902. doi: 10.13930/j.cnki.cjea.170903

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Abstract:
In the process of transition from traditional agriculture to modern agriculture, the role of agriculture has been changing from single to multiple functions. Comprehensive evaluation of the degree of synergy of agro-ecosystems can guide sustainable regional development. The dry farming area in Northeast China is not only an important grain production base, but also a severe soil erosion area in China. Due to excessive long-term fertilizer application, unreasonable farming systems and management measures, agro-ecological environments in the dry farming areas have faced enormous pressure. In this research, the grain production and soil data for 85 counties in dry farming areas of Northeast China were used as basic materials, which included socio-economic data from agricultural statistics yearbooks of three northeastern provinces from 2005 to 2015 and soil physic-chemical parameters obtained from soil samples collected in the study area in May 2017. The spatial variations in synergy and trade-offs among agro-production functions, agro-living functions and agro-ecological functions of agro-ecosystem were analyzed based on the synergetic model and root mean square error (RMSE) at different time periods. The aim of this research was to reveal the temporal and spatial evolution characteristics of the three agro-ecosystem functions stated above. The results showed that the degree of the synergy of agro-ecosystem was low for the dry farming areas in Northeast China, dropping by 0.12 for the period 2005-2015. The degrees of synergy of agro-production function and agro-ecological function were dropped by 0.03 and 0.45, respectively. However, the synergy degree of agro-living function increased slightly. Except for drying farming areas in Liaoning Province, the synergy degree of agro-ecosystem decreased significantly in Jilin Province and Heilongjiang Province, indicating that the synergy among three functions of agro-ecosystem was in disorder. There were spatial and temporal trade-off relationships among various functions of agro-ecosystem. For the period 2005-2010, the trade-offs between agro-production function and agro-ecological function, and between agro-living function and agro-ecological function benefited from the ecological function. However, the trade-offs benefited from the production functions and living functions for the period 2010-2015. The main reasons were the fluctuations in the trade-off relationships among three functions of agriculture and changes in the related benefit directions. It was suggested that the synergy degree of agro-ecosystem and the relationships among agro-production function, agro-living function and agro-ecological function were quantitatively describable using the synergetic model and root mean square error. It was an effective way of identifying the structural factors that caused changes in agro-ecosystems by the two methods. The results provided critical references for sustainable development of agro-ecosystem in the dry farming areas of Northeast China.

Analysis of ecological service value of ecological land of Bashang area based on ecological factor division

WANG Xiaoqing, NIU Zhijun, KANG Wei, ZHANG Liqiang, ZHANG Junmei

2018, 26(6): 903-915. doi: 10.13930/j.cnki.cjea.171085

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Abstract:
As a vital ecological barrier and biodiversity conservation base of the Beijing-Tianjin-Hebei Region, Bashang area plays an irreplaceable role in guaranteeing ecological security and water resources supply. In this study, the ARCGIS 10.2 software was used to zone the typical regions of land ecological elements through overlapping the two major ecological elements-soil and topography in Bashang area. For further research, an ecological land classification system was constructed through the combination of current land use classification system and ecosystem services function. On this basis, the equivalent factor method was used to estimate the values of ecosystem services of ecological lands in various regions of Bashang for 2015 and then the location revised based on unit area grain yield. The research aim at providing theoretical basis for the planning of ecological land use and the formulation of regional ecological protection and management policies in Bashang area. The results showed that:1) the general trend in grain yield in the Bashang area gradually increased from the central region into the two projecting wings. Both the regions of low and middle mountains of eroded cinnamon soil in the southeast of the study area were high-yield regions with yields of above 5 000 kg·hm^-2. Then low-yield areas included the region of chestnut soil basalt planform in Zhangbei County and the region of middle mountain eroded skeleton soil in Shangyi County, with yield less than 2 500 kg·hm^-2. 2) Grassland and woodland were the main types of ecological land in Bashang, accounting for 73.95% of the total area. The ecological land areas of regions of middle mountain of eroded marshy soil, alluvial aeolian plateau of marsh soil, middle mountain of eroded gray forest soil, alluvial aeolian plateau of gray forest soil accounted for over 95% of the various type areas. On the contrary, the proportion of ecological land of saline soil lake plateau region was smallest, accounting for only 39.74%. 3) The total value of ecological services in Bashang reached 63.48 billion ￥ in 2015. The maximum ecosystem service value was in the region of middle mountain of eroded brown soil in the eastern part of the Bashang area, which was mainly provided by the woodland. The ecosystem service value in the saline soil lake plateau region in the northwestern part was the smallest, which was basically provided by grassland. The research reflects that both soil type and geomorphic form influenced land production capacity, thus influencing ecological service value.

Evaluation and barrier factors analysis of agricultural circular economy based on IUOCE:A case study of Jiangxi Province

HUANG Heping, LI Yali, QIAO Xuezhong

2018, 26(6): 916-925. doi: 10.13930/j.cnki.cjea.170963

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Abstract:
Lots of researches have focused on development evaluation and obstacles analysis of agricultural circular economy from perspectives of economic and social development, resource input reducing, resources reusing and environment protection based on "3R" rules while neglecting the rural consumption. In this study we introduced rural resident consumption into the index system and used the method of input-utilization-output-consumption-effect (IUOCE) process of agricultural production to clarify the developmental level and obstacles of agricultural circular economy in Jiangxi Province in 2000-2015. Five categories (input, utilization, output, consumption and effect) including 20 evaluation indicators composed the evaluation system, and the weights of indicators were determined with the entropy method. Based on the factor contribution degree, index deviation degree and obstruction degree, the obstacle indicators of agricultural circular economy in Jiangxi Province were diagnosed. The results showed an upward trend in the utilization indicators, output indicators, consumption indicators and effect indicators of agricultural circular economy in Jiangxi Province from 2000 to 2015. The order of rising rate was output indicators > effect indicators > consumption indicators > utilization indicators. However, input indicators had a downward trend. The growth of agricultural circular economy in Jiangxi Province had an overall upward trend from 2000 to 2015, with an average annual growth rate of 3.43% which was a relatively low rate. The main obstacle indicators that affected the development of agricultural circular economy in Jiangxi Province were fertilizer effective utilization factor, fertilizer use intensity, arable land area per capita, forest cover rate and net income per farmer in 2000-2008, while they were fertilizer use intensity, multiple cropping index, effective irrigation coefficient and sown area of crops in 2009-2015. The input and utilization indicators were the main obstacle factors that affected the development of agricultural circular economy in Jiangxi Province from 2000 to 2015. While the obstacle degrees of input indicators and utilization indicators gradually increased in trend, those of output indicators, consumer indicators and effect indicators generally decreased in 2000-2015. In summary, the developmental level of agricultural circular economy in Jiangxi Province was overall in an upward trend, and the obstacle indicators became less but the obstacle degree became high.

Technical perception, environmental awareness and adoption willingness of agricultural cleaner production technology

CHEN Zhukang, ZHANG Junbiao, HE Ke

2018, 26(6): 926-936. doi: 10.13930/j.cnki.cjea.171051

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Abstract:
The popularization and adoption of agricultural cleaner production technology are critical for sustainable agricultural development in China. Most studies have only included technical perception variables or environmental cognitive variables as the many explanatory variables failing to include technical awareness variables or environmental cognitive variables in the analytical framework to analyze the key factors that affect farmers' willingness to adopt agricultural cleaner production technology. In fact, technical perception and environmental cognition play an important role in the adoption of agricultural cleaner production technology. Thus, this study analyzed the willingness of farmers to adopt agricultural cleaner production technology from points of views of both technical perception and environmental cognition based on survey data on 836 micro-farmers in 11 provinces in China. The effects of adopting agricultural cleaner production technology and differences among various peasant groups were also investigated through the use of binary logistic regression model. The results showed that:1) when farmers' perception of agricultural cleaner production technology reduced by one level, the probability of adoption of the agricultural cleaner production technology dropped by 5.93%. Farmers had a higher degree of awareness of the use of agricultural cleaner production technologies. Production techniques were more readily adopted among agricul-tural cleaner production technologies. When the farmers' perception on environmental change improved by one level, the willingness to adopt increased by 12.57%. It was obvious that farmers were more sensitive to climate change and were more likely to adopt the agri-cultural cleaner production techniques. 2) The key factor that affected farmers who perceived "ease of use" was the feel of environmental changes. Also the adoption willingness of farmers who was "technical perception of difficult" was mainly influenced by the perception on environmental changes and the usefulness of changes. It suggested that raising the level of perception of peasant households on envi-ronmental change significantly promoted the willingness to adopt cleaner agricultural production technology. 3) The key factor that in-fluenced the adoption willingness of farmers who was "sensitive to environmental change" was the ease-to-use of technology. Also for farmers who were "lagged to environmental change", the willingness was mainly affected by age, education level, family labor size and cultivated land area. The adoption processes of agricultural cleaner production technology still relied on traditional habits. There were obvious differences in the willingness of farmers in different sample groups. The research conclusions provided the critical references for agricultural cleaner production in China. Based on the results, in order to improve the level of technical knowledge, farmers' environmental cognition, popularization and application of agricultural cleaner production technology, there was the needs to target edu-cation. This should be done for different types of farmers in order to increase the degree of technical understanding and environmental awareness of farmers. This was necessary to promote the application of agricultural cleaner production technologies in China.

2018 Vol. 26, No. 6