中国生态农业学报(中英文)

Green development of paddy field farming systems in the Yangtze River Economic Belt

HUANG Guoqin

2020, 28(1): 1-7. doi: 10.13930/j.cnki.cjea.190500

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Abstract:
Currently, implementing the development strategy of Yangtze River Economic Belt and promoting green, high-quality and sustainable development of Yangtze River Economic Belt is one of China's regional coordinated development strategy. The rice field farming systems is an important part of the whole agricultural farming systems in the Yangtze River Economic Belt. Realizing the green development of rice field farming systems in the Yangtze River Economic Belt is of great significance for maintaining food security, food safety and ecological security in the Yangtze River Economic Belt and even the whole country. The rice field farming systems have remarkable characteristics such as ancient origin, diversity of patterns, complex structure, the efficiency of function and the international influence. At present, the development of rice field farming systems in the Yangtze River Economic Belt are faced with outstanding problems and challenges such as reduction of maturity, excessive investment, waste of resources, weakening of land, weak foundation and decreased efficiency. In order to realize green development of rice field farming systems, the following countermeasures and measures should be taken on the premise of following the principle of "common protection, no large scale development", "ecological priority and green development":1) Green coverage, "all year round, seasonal green" rice fields; 2) Green fertilizer, make full use of green manure, farm fertilizer, biogas, marsh residue, as well as bio-fertilizer, special fertilizer and other fertilizer soil, improve the soil fertility of rice fields; 3) Green prevention and control, the application of agricultural control technology (such as the implementation of crop rotation), biological control technology, ecological control technology and physical and chemical booby-trapped technology to prevent and control rice plant diseases, insects, grasses, rats, and birds; 4) Green repair, restoration of "degraded rice fields" and "polluted soil" by means of rotational fallow, deep-till deep pine, conservation farming, straw return to the fields, increased application of organic fertilizer, application of repair agents, planting of green manure and restoration of plants; 5) Green utilization, including three-dimensional utilization, comprehensive utilization and recycling of agricultural resources and wastes in paddy fields; 6) Green products, construct paddy fields of Yangtze River economy to become production base with pollution-free, green and organic agricultural products.

Impact of planting structure changes on agricultural water requirement in North China Plain

ZHANG Yafang, GUO Ying, SHEN Yanjun, QI Yongqing, LUO Jianmei

2020, 28(1): 8-16. doi: 10.13930/j.cnki.cjea.190490

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Evaluating farmland water requirements under different planting structures is an important basis for adjusting the agricultural planting structure and formulating feasible regional irrigation schemes. In order to quantitatively estimate the impact of planting structure changes on agricultural water requirement in the North China Plain (NCP), this paper extracted the main crop types and their planting areas based on MODIS NDVI data and TM/ETM remote sensing images from 2002 and 2012. The water demand of seven main crops in the NCP was calculated based on the crop coefficient method and the influence of planting structure change on crop water requirements in NCP was analyzed. The results showed that firstly:from 2002 to 2012, the main crop planting area decreased by 60.7×10⁴ hectares. Among them, the planting area of the four crops was significantly reduced:winter wheat-summer maize (-4.318×10⁵ hm²), cotton (-3.243×10⁵ hm²), rice (-9.3×10⁴ hm²), and spring corn (-4.9×10⁴ hm²). The crops for which planting area increased were:forest fruit (+1.661×10⁵ hm²) and vegetables (+1.26×10⁵ hm²). Secondly, from 2002 to 2012, the total water demand for major crops in the NCP decreased from 74.27 billion m³ to 69.55 billion m³ (a decrease of 6.37%). Among this, the types of crop with reduced water demand were as follows:winter wheat-summer maize (-3.54 billion m³), cotton (-2.43 billion m³), rice (-0.75 billion m³), and spring maize (-0.21 billion m³). On the other hand, fruit trees and vegetables both caused an increase in water demand 1.12 billion m³ and 1.07 billion m³, respectively. Spatially, crop water demand in the NCP showed an overall decreasing trend, with only the Hebei Plain, northwest Shandong Province, and the coastal plain near the urban periphery displaying increasing water demand. The largest increase in water demand occurred in the coastal plain. Finally, the reduction of crop water demand in the NCP caused by reduction of crop planting area amounted to 4.47 billion m³, while that caused by planting structure adjustments only amounted to 0.25 billion m³. Hence, the reduction of the planting scale is the main reason for the decrease in crop water demand in the NCP.

Climatic potential productivity and stress risk of winter wheat under the background of climate change in Anhui Province

LU Yanyu, SUN Wei, TANG Wei'an, HE Dongyan, DENG Hanqing

2020, 28(1): 17-30. doi: 10.13930/j.cnki.cjea.190463

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Climate change has significantly influenced agricultural production in Anhui Province, a main food-producing region in China. For the comprehensive assessment of the beneficial and detrimental effects of climate change on winter wheat, this study established evaluation indices system and method of climatic potential productivity and stress risk. The responses of climatic potential productivity and stress risk of winter wheat to climate change of Anhui Province were then analyzed. Lastly, comprehensive climate-suitability zoning was proposed by considering the effects of climate on winter wheat yield and yield stability. Applying a stepwise evaluation method and dynamic growth parameters produced an estimated average climatic potential productivity of winter wheat of 12 391 kg·hm^-2 in Anhui Province. During 1961-2015, climatic potential productivity significantly increased in the region north of the Huaihe River, but deceased in the region south of the Huaihe River. Heat, cold, waterlogging, and drought stresses were analyzed by considering the effects of climatic conditions deviating from the optimal range during winter wheat growth. Based on the surpassing probability of climate stress, this study further assessed the climatic risks to winter wheat. Heat stress on winter wheat increased significantly, but a decreasing trend was found in variation in cold stress. The stress of waterlogging and drought exhibited no significant change trend. The northern and southern regions of Anhui Province were dominated by high climatic risk to winter wheat, but relatively low risk was found in the central region. The high climatic risk in the region north of the Huaihe River was primarily attributed to drought and cold stress, while the southern region was dominated by the waterlogging risk. The climatic suitability of winter wheat assessed with climatic potential productivity and stress risk was lower in southern and northern regions, but higher in the central regions of Anhui Province. The spatial distribution of winter wheat planting was generally consistent with climate suitability, while the planting layout could be further optimized to adapt to the climate.

Canopy microenvironment change of peanut intercropped with maize and its correlation with pod yield

LIN Songming, MENG Weiwei, NAN Zhenwu, XU Jie, LI Lin, ZHANG Zheng, LI Xinguo, GUO Feng, WAN Shubo

2020, 28(1): 31-41. doi: 10.13930/j.cnki.cjea.190525

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Field trials of the single cropping of peanuts and broad-sown intercropping of maize and peanuts were conducted in 2015 and 2016. Changes in peanut canopy transmittance, light intensity, canopy temperature, and humidity after the podding stage under different planting modes were monitored, and the correlations between them and pod yield were analyzed. Our results showed that, first, compared with a peanut monoculture, maize/peanut intercropping significantly reduced the light intensity of the canopy, the transmittance of the top and middle canopy, and the average temperature of the canopy from 9:00 a.m. to 11:00 a.m., and increased the average humidity of the canopy. Second, peanut canopy light intensity exhibited a single peak curve on sunny days, and the canopy light intensity of monocultured peanuts was significantly higher than that of intercropping. The difference in light intensity between a monoculture and intercropping was greater in the morning (when light intensity increased) and the afternoon (when light intensity decreased), while the difference between the two values decreased at noon during the direct-sunlight period. The ambient canopy temperature of peanuts decreased under intercropping in the night and before and after noon, compared with monoculture, with an observed highest difference of 4.9℃. Intercropping increased the relative humidity of the canopy during daytime, with a recorded highest difference of 21.03%. Third, under experimental conditions, the canopy environmental temperature and illumination at the podding stage were positively correlated with peanut pod yield, while the canopy environmental humidity was negatively correlated with pod yield, especially at the podding stage. Multivariate linear stepwise regression analysis showed that the most important environmental factors affecting peanut yield were canopy illumination and circumferential humidity at podding stage, and canopy circumferential humidity at the full-fruit stage. Path analysis showed that, besides directly affecting yield, illumination had a high impact on peanut pod yield by affecting canopy environmental humidity, indicating that the positive effect of illumination on yield can be improved by coordinating the relationship between illumination and humidity under intercropping conditions. In this experiment, the decrease in canopy light intensity and transmittance of intercropping and the increase in canopy relative humidity of intercropping were the main climatic factors limiting pod yield. It is possible that the yield of intercropped peanuts could be increased by planting them from east to west, which will increase the effective illuminance of the canopy at 9:00-11:00 a.m. and reduce the relative humidity.

Effects of sowing dates on lint yield, fiber quality, and use of nitrogen, phosphorus and potassium in cotton field-seeded after barley or oilseed rape harvest in Yangtze River Valley, China

YANG Changqin, ZHANG Guowei, LIU Ruixian, WANG Xiaojing, NI Wanchao

2020, 28(1): 42-49. doi: 10.13930/j.cnki.cjea.190534

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This study aimed to evaluate the effects of sowing date on lint yield, quality, as well as nutrient uptake and use of cotton field-seeded after barley or oilseed rape harvest in the downstream Yangtze River Valley. Sowing dates were randomly assigned (15-May, 25-May, 4-June, 14-June, and 24-June), using short-season cotton (CCRI 50) in fields in Nanjing, Jiangsu Province of China, between 2017 and 2018. The results showed that:with delayed sowing date, the growing process slowed, the daily mean temperature and sunshine hours were lower during the flowering and bolling stages, and the effective accumulated temperature increased until it reached a peak on the sowing date of 4-June. These trends suggested that temperature and sunshine were both higher before the sowing date of 4-June. The biomass and nitrogen, phosphorus and potassium accumulation of cotton plants and reproductive organs decreased with sowing date delay. The accumulation rate in biomass and nutrient peaked even earlier, on the sowing date of 15-May, 25-May, and 4-June than on sowing date of 14-June and 24-June. As the sowing date was delayed, boll number and lint yield both decreased. Compared with the 15-May sowing date, the lint yields decreased by 13.1%-16.9% for sowing dates of 25-May and 4-June, and by 26.9%-33.5% and 58.2%-62.0% for sowing dates of 14-June and 24-June, respectively. Nutrient uptake of nitrogen, phosphorus, and potassium for 100 kg lint yield increased with sowing date delay, while the nutrient use efficiency decreased. The fiber quality was better for sowing dates of 4-June and 14-June than for other sowing dates. In summary, sowing from 15-May to 4-June is suitable to achieve high yield in short-season cotton field-seeded after barley or oilseed rape harvest in the downstream Yangtze River Valley. Sowing later during this period would, on the other hand, lead to high fiber quality.

Effects of harvesting date on mechanical grain-harvesting quality of spring maize in Sichuan Province

KONG Fanlei, ZHAO Bo, WU Yawei, LI Xiaolong, CHEN Xiang, KE Yongpei, YUAN Jichao

2020, 28(1): 50-56. doi: 10.13930/j.cnki.cjea.190544

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Studying the impact of harvesting date on mechanical grain-harvesting quality is of great importance to determine a suitable harvesting date and promote the mechanical grain harvest technology. This paper describes an experimental study of the effects of harvesting date (31^st July, and 7^th, 13^th, 19^th, 25^th, and 31^st August) on mechanical grain-harvesting quality and the relationship between grain moisture content and mechanical grain-harvesting quality in Sichuan spring maize. The results showed that, with a delay in harvest date, grain moisture content decreased gradually, and the broken-grain rate decreased rapidly at first and then increased slightly. The impurity rate decreased rapidly and tended to be stable, while the ear-loss rate increased significantly and the variation in grain loss rate was not notable. The total grain loss rate was primarily associated with ear loss, which accounted for 76.34% of the total average grain loss. With a delay in harvest date, the differences in broken-grain and impurity rates between varieties decreased gradually while they increased for ear-loss and total grain-loss rates. Grain moisture content was the key factor affecting the quality of mechanical grain harvest, the relationship between the broken-grain rate and grain moisture content could be described by the equation y=0.032 9x²-1.332 8x + 15.529 (R²=0.55^**, n=72). The broken-grain rate was lower than 5% when the moisture content was between 10.76% and 29.76%. The relationship between the impurity rate and moisture content could be described by the equation y=0.031 8e^{0.118 5x} (R²=0.71^**, n=72), and the grain impurity rate was lower than 3% when grain moisture content was lower than 38.37%. The relationship between the ear-loss rate and moisture content could be described by the equation y=2 083.3/x^2.135 (R²=0.68^**). The relationship between the total grain-loss rate and moisture content could be described by the equation y=911.02/x^1.769 (R²=0.68^**), and the total grain-loss rate could be lower than 5% when grain moisture content was higher than 18.96%. A delayed harvest was associated with a decrease in the broken-grain and impurity rates and an increase in the risk of ear-loss and the total grain-loss rate. The optimal grain moisture content for mechanical harvesting in Sichuan spring maize was 18.96%-29.76% and the optimal mechanical-grain harvesting date was between August 7 and August 19 in this study, which was approximately 10-15 days later than the traditional harvest date.

Effects of soil moisture before sowing and phosphate fertilizers on grain filling characteristics and yield of dryland wheat

YUAN Yaqi, SUN Min, LIN Wen, CAO Biyun, TIAN Xin, GAO Zhiqiang, LI Tingliang

2020, 28(1): 57-67. doi: 10.13930/j.cnki.cjea.190423

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The water needed for dryland wheat growth is provided by soil moisture and rainfall. To some extent, the wheat yield is determined by soil moisture before sowing. This study aimed to analyze the relationship between the grain filling process and water consumption in the Loess Plateau (China), and investigate the response of dryland wheat yield to soil moisture before sowing and phosphate fertilizer. A field experiment was conducted in the southern Shanxi Province of China. There were two factors in the experiment:1) soil moisture before sowing in the 0-100 cm soil layer, including three levels at W1 (248 mm), W2 (233 mm), and W3 (205 mm); and 2) phosphorus fertilizer rates at P1 (75 kg·hm^-2) and P2 (180 kg·hm^-2). We first investigated the changes in total wheat water consumption, soil water consumption, water consumption during each growth stage, yield and yield components, and grouting process under different treatments. Collected data were analyzed using multiple regression with a Logistic fit. The results showed that soil moisture before sowing had a significant effect on water consumption during the greening-jointing and jointing-anthesis stages. The total water consumption during the growth period, the soil water consumption, and the proportion of total water consumption, yield, spike, and thousand-grain weights were also influenced significantly by soil moisture before sowing. Compared with W3, yields of W1 and W2 significantly increased by 14.89% and 8.66%, respectively. Phosphate fertilizer has a significant effect on yield, spike, thousand-grain weight and water consumption in the wheat sowing-greening, greening-jointing, and jointing-anthesis stages. With the increase of phosphorus fertilizer, sowing-jointing water consumption decreased and jointing-anthesis water consumption, yield, and thousand-grain weight increased. The wheat grouting equation showed that the duration of the fast increase period increased with increasing soil moisture before sowing, and the duration of the increasing period and the fast-increasing period both increased with increasing phosphate fertilizer rate. The coefficient of variation of grain increased by 25% during the slow-increasing period; the wheat water (phosphorus) fertilizer equation showed that high yield can be obtained at the 0-100 cm soil moisture boundary before sowing at 253 mm. Additionally, with the same soil moisture before sowing, the yield increased with increasing phosphorus fertilizer rate. The results show that the water consumption of dryland wheat in the jointing-anthesis stage was sensitive to soil moisture before sowing and phosphate fertilizer application. The duration of the fast-increasing period in the filling process had a better response to soil moisture before sowing and phosphate fertilizer, and the variation of the slow-increasing period impacted on grain weight.

Effect of nutrient expert recommendation fertilization on rice yield and fertilizer use in northern Jiangsu Province

SONG Die, CHEN Xinbing, DONG Yangyang, SHA Zhimin, XU Xinpeng, CAO Linkui

2020, 28(1): 68-75. doi: 10.13930/j.cnki.cjea.190506

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The overuse of nitrogen fertilizer, inadequate fertilization rate and time, and low fertilizer use efficiency in intensive agriculture have become the main limiting factors to farmers' income and sustainable agricultural development in northern Jiangsu Province, China. In order to optimize fertilizer management, improve the nutrient use efficiency, and reduce environmental risks in paddy fields in this region, we conducted nutrient expert (NE)-based fertilizer recommendation based on soil properties, targeted yield, and nutrient management information. Field experiments were designed to investigate the effects of NE on rice yield, economic benefit, nutrient uptake, and fertilizer use efficiency. Five treatments were used in the experiments, including (1) nitrogen, phosphorus and potassium fertilizer input calculated using NE, (2-4) eliminating nitrogen, phosphorous or potassium input in the NE treatment, and (5) farmers' conventional fertilization (FP). Results showed that, when compared with the FP treatment, partial productivity of N and P₂O₅ in the NE treatment was 44.77% (P < 0.05) and 6.32% higher respectively, while partial productivity of K₂O decreased significantly by 33.55% (P < 0.05). The recovery efficiency of N and K₂O in NE was significantly higher than that of FP by 4.91% and 19.35%, respectively; while the recovery efficiency of P₂O₅ was approximately the same as that in FP. Where the NE treatment involved reducing nitrogen fertilizer input and ensuring the balanced application of phosphorus and potassium fertilizer, the rice yield and farmers' income in this treatment were improved by 2.23% and 6.24%, respectively; however there were no significant differences compared to FP. The phosphorus and potassium accumulation in rice grains in the NE treatment had increased by 10.32% (P > 0.05) and 51.63% (P < 0.05), respectively. In conclusion, the use of NE-based recommendations resulted in an adequate ratio of N, P, and K, as well as optimizing fertilizer management, promoting the absorption and utilization of N, P, and K in rice, and improving rice yields and farmers' income. Therefore, we highly recommend using the NE system for fertilizer management in rice paddy fields in the northern Jiangsu Province of China.

Effects of shading and waterlogging following anthesis on starch synthesis and dry matter accumulation in wheat grain

WANG Min, WANG Shaoyu, WU Jiajia, XU Kaifang, WANG Tao, HE Qifang, XING Xiaoli, YAO Wenzheng, ZHANG Wenjing

2020, 28(1): 76-85. doi: 10.13930/j.cnki.cjea.190540

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Focusing on the reduced wheat yield caused by continuous rain following anthesis in the middle and lower reaches of the Yangtze River, a pot experiment was designed to investigate the effects of shading and waterlogging on starch synthesis and dry matter accumulation in wheat grains, to provide information regarding adverse resistance cultivation and stable yield of wheat in the area. Two wheat varieties - 'Yangmai 18' (waterlogging-insensitive type) and 'Wanmai 52' (waterlogging-sensitive type) - that are domain varieties in the Yangtze River Basin of China were selected to investigate the effects of 7-, 11-, and 15-day shading and waterlogging treatments following anthesis on starch synthesis and dry matter accumulation in wheat grains. The results indicated that there were no significant differences between the control and shading and waterlogging treatments in terms of the activities of adenosine diphosphate-glucose pyrophosphate (AGPase), soluble starch synthase (SSS), and bound starch synthase (GBSS) in wheat grains during the earlier grain-filling stage (10-15 days after anthesis). However, with the development of the grain-filling process, the difference between the control and shading and waterlogging treatments increased. In the mid-grain-filling stage (20 days after anthesis), when the activities of the three key enzymes were highest. The 11-and 15-day shading and waterlogging treatments decreased the activity of AGPase in wheat grain by 1% and 10% for 'Yangmai 18', and by 11% and 24% for 'Wanmai 52', respectively. Further, the activity of SSS was decreased by 5% and 11% for 'Yangmai 18', and 9%, 32% for 'Wanmai 52', respectively, compared with the control. In addition, the activities of SSS and GBSS under 11-and 15-day shading and waterlogging treatments were significantly lower than those in the control during the late grain-filling stage. Simulating the process of starch accumulation and grain filling with a Logistic equation showed that compared with the control, the shading and waterlogging treatments shortened the duration of the slow increasing stage and decreased the average grain-filling rate, average and peak starch accumulation rates, and cumulative wheat starch and dry matter amounts. Simultaneously, the shading and waterlogging treatments decreased the grain number and 1000-kernel weight of wheat, thereby lowering the yield. The extented shading and waterlogging treatments duration induced a decline in the activities of SSS and GBSS as well as the starch and dry matter accumulation amount in wheat grains and yield. The waterlogging-insensitive variety 'Yangmai 18' showed slight decreases compared with the waterlogging-sensitive variety 'Wanmai 52' in each index. Shading and waterlogging stresses following anthesis of wheat decreased the activities of AGPase, SSS, and GBSS and affected the starch and dry matter accumulation in wheat grains, thereby leading to yield loss.

Simulation model of the grain protein content of dryland wheat based on APSIM

NIE Zhigang, LI Guang, WANG Jun, DONG Lixia, LU Yulan, LUO Cuiping, MA Weiwei

2020, 28(1): 86-95. doi: 10.13930/j.cnki.cjea.190135

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Accurate simulation of grain protein accumulation is of considerable importance for the effective regulation of high-quality wheat production on drylands in hilly loess regions. Using field experimental data of Anjiagou Village, Fengxiang Town, Anding District, and Dingxi City from 2016 to 2017 and meteorological data of Anding District and Dingxi City from 1971 to 2017, a dryland wheat grain protein content model was established using the Agricultural Production Systems Simulator (APSIM) and tested using correlation analysis. Quantitative analysis was conducted on the effect of different tillage methods and sowing dates on wheat grain protein content. Four tillage methods were used:conventional tillage (T), conventional tillage with straw cover (TS), no tillage (NT), and no tillage with straw cover (NTS). Further, three sowing dates were set:early sowing date (ESW), normal sowing date (NSW), and late sowing date (LSW). The findings revealed that under the tested tillage methods and sowing dates, the root mean square errors between the simulated and measured yield and grain protein content were 66.4-121.9 kg·hm^-2 and 0.2%-1.1%, respectively, and the normalized root mean square errors were 1.23%-9.66% and 1.31%-9.94%, respectively. These results indicate a satisfactory precision. Sowing date had a significant effect on the wheat grain protein content for drylands. The highest grain protein content was found with NSW, but the content decreased significantly with LSW. The relationship between wheat yield and grain protein content for the four tillage methods showed a quadratic curve in an open downward direction. As the grain protein content increased, the yield first increased and then decreased. TS and NTS (straw cover) were more conducive to the increase in the wheat grain protein content than T and NT (no straw cover).

Effect of long-term application of biochar and straw on soil organic carbon in purple soil aggregates of sloping uplands

LIN Hongyu, ZHOU Minghua, ZHANG Bowen, LI Ziyang, ZHU Bo

2020, 28(1): 96-103. doi: 10.13930/j.cnki.cjea.190614

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The effects of biochar and straw application on the distribution of soil organic carbon (SOC) in purple soil aggregations of sloping uplands were explored from a long-term perspective. Five long-term fertilization treatments were included:no fertilizer (control, CK), mineral fertilizer application (NPK), crop straw residue application (RSD), a combined application of biochar and mineral fertilizer (BCNPK), and a combined application of crop straw residue and mineral fertilizer (RSDNPK). Soil samples were separated into > 2 mm large macroaggregates, 0.25-2 mm small macroaggregates, 0.053-0.25 mm microaggregates, and < 0.053 mm slit-clay microaggregates by sieving. The mass fraction of soil aggregations, organic carbon content, mean weight diameter, and geometric mean diameter of aggregations were measured. The results showed that the application of biochar and straw increased SOC content and stabilized the structure of aggregations compared with both CK and NPK treatments. In comparison with CK, SOC contents significantly increased by 43.1% under NPK treatment, 82.9% under RSD treatment, 79.1% under RSDNPK treatment, and 90.5% under BCNPK treatment. SOC stocks of topsoil increased significantly by 34.0% under NPK treatment, 68.2% under RSD treatment, 65.2% under RSDNPK treatment, and 74.3% under BCNPK treatment compared with CK treatment. In addition, the content of 0.25-2 mm aggregates of RSD treatment reached 45.5%, which was 57.7% higher than that of CK; more soil aggregations were concentrated on 0.25-2 mm aggregates. As compared with CK, the SOC content of 0.053-0.25 mm aggregates was reduced by straw and biochar treatments. The trends for NPK and RSD treatments were similar to those for CK, but RSDNPK and BCNPK treatment showed an increasing trend in organic carbon content in aggregates with decreased particle size. RSDNPK and BCNPK treatments significantly increased the SOC content and enhanced the stability of soil structure, but BCNPK treatment was superior to RSDNPK treatment in increasing SOC content, and RSDNPK treatment was more effective in stabilizing soil structure. BCNPK treatment and RSDNPK treatment are therefore effective management measures that can maintain and improve soil fertility of purple-soil-cultivated land.

Temporal-spatial changes in cultivated land quality in a black soil region of Northeast China

YAO Dongheng, PEI Jiubo, WANG Jingkuan

2020, 28(1): 104-114. doi: 10.13930/j.cnki.cjea.190485

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Temporal-spatial variations in cultivated land quality in a typical black soil region in Northeast China were explored with 16 evaluation indices by means of the Delphi method, with weights determined by an analytic hierarchy process based on the National Standard of Cultivated Land Quality Grade (GB/T 33469-2016). ArcGIS software was used to evaluate the quality of cultivated land in the region using the same system and the same grading standard between 2008 and 2018. The goal was to identify temporal and spatial changes in cultivated land quality in the study area during the past 10 years, and the reasons for changes in the cultivated land quality. The results showed that the quality of cultivated land in the study region was dominated by medium-and low-level land in 2008, with an average cultivated land quality grade of 5.14. In 2018, the quality of cultivated land was mainly in medium-and high-level land, with an average cultivated land quality grade of 3.92. Over the past 10 years, the quality increased by 1.22. The area of first-to fourth-grade cultivated land had increased, and the area of fifth-to tenth-grade land had decreased. Meanwhile, the cultivated land grade rose 8 levels at most, and fell 7 levels most. The area of cultivated land that increased its grade was 3.5 times that of the land that experienced a decrease in grade. The quality of cultivated land in the mid-west and northwest regions of the study area increased significantly, while the south and northeast saw more decrease. This study standardized the basis of a temporal-spatial comparison analysis of cultivated land quality in the study area and revealed temporal-spatial variation characteristics of the study area, providing direction for improving cultivated land quality and sustainably utilizing and managing black soil in the future.

Seasonal variation of meat duck manure production characteristics

YAN Ting, ZHU Zhiping, GAO Lifu, LU Lianshui, SUN Haiceng, YU Xin, LUO Qianliang

2020, 28(1): 115-123. doi: 10.13930/j.cnki.cjea.190644

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This study aimed to explore the characteristics of the manure of meat duck, and to assess its characteristics of pollutant emission in different seasons, so as to provide a basis for waste disposal and resource utilization of meat duck farms. Feeding experiments were conducted in 4 seasons and 100 Pekin type Z meat ducks were raised in each season for 37 days. Their food intake and manure production were recorded daily, and the relevant components in the feed and manure were measured regularly. Results showed that the Zn content in duck manure was the highest in autumn, whereas TN, P, and Cu contents were the highest in winter. In winter, TN content in manure was significantly higher than that in summer and autumn. P and Cu contents in winter were significantly higher than that in all other seasons. Cu and Zn contents in manure were the lowest in spring. Average moisture content of duck manure was 84.61%, being the highest in summer and lowest in spring. Average content of organic matter was 83.38%, and the seasons ranked winter > spring > autumn > summer. Manure productions were 338.3 g·d^-1·head^-1, 275.9 g·d^-1·head^-1, 317.6 g·d^-1·head^-1, and 327.0 g·d^-1·head^-1 in spring, summer, autumn, and winter, respectively. Excretion coefficients of TN, P, Cu, and Zn were 2.13 g·d^-1·head^-1, 2.48 g·d^-1·head^-1, 2.56 mg·d^-1·head^-1, and 21.10 mg·d^-1·head^-1, respectively. Daily excretion of TN in spring and winter was significantly higher than that in summer and autumn, daily excretion of P was significantly higher in winter than in the other seasons, and daily excretion of Cu in summer was not significantly different from that in spring but significantly lower than that in autumn and winter. TN excretion accounted for the lowest proportion in autumn and the highest in spring, whereas P excretion accounted for the highest proportion in autumn and the lowest in spring. There was a highly significant positive correlation between the excretion of TN, P, Cu, and Zn and the intake of the corresponding elements. This research showed that seasonal (dietary) factors can significantly affect moisture content, organic matter, TN, P, Cu, and Zn contents in the manure of meat duck. There were significant differences in feed intake, manure production, and TN, P, Cu, and Zn excretion among the seasons, and the excretion of each element in each season was significantly correlated with the intake of the corresponding element.

Identification of potential abandoned farmland and driving factors in Honghe Hani Rice Terrace

LIU Zhilin, DING Yinping, JIAO Yuanmei, LIU Chengjing

2020, 28(1): 124-135. doi: 10.13930/j.cnki.cjea.190521

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Abstract:
The identification of farmland at risk of abandonment is not only the scientific basis for utilization planning and management of overall farmland in a region but also a key measurement of agricultural sustainability. However, the accuracy of identification results can be affected by the gradualness and complexity of abandonment process and limited by the development of current relevant technologies. In response to these challenges, a set of scientific identification methods have been established for use in the World Heritage Site of Hani Rice Terraces. In the first of two steps, a farmland abandonment risk index (FARI) is constructed using factors such as road access, slope, elevation, water, precipitation, temperature, population, rice production, among others. Second, the farmlands at high risk of abandonment are identified through hierarchical cluster analysis. The results suggest first that farmland can be divided into three categories of abandonment threat:stable, low-risk abandonment, and high-risk abandonment. These categories accounted for 57%, 35%, and 8% of the total farmland area of the heritage site, respectively. Overall, the results indicate that farmlands at the heritage site were stable. Second, the variation trend for the FARI in longitude and latitude was:north was higher than south and east was higher than west. Third, in terms of spatial patterns, farmlands at high risk of abandonment (34.95 km²) were distributed at the boundary of Yuanyang County and composed of two parts (from Ganiang and Fengchunling to Xiaoxinjie, from Majie to eastern Niujiaozhai). The region was a key area for ecological restoration in the region because of poor cultivating conditions. Fourth, by analyzing the factors influencing the three types of farmland, the following results were obtained. Stable farmland was primarily affected by population, rice production, and road access, followed by slope, water, and elevation. Stability was positively associated with population and rice production and negatively associated with road access, slope, water, and elevation. Farmland at low risk of abandonment was most affected by precipitation, and other factors had less impact. Farmland at high risk of abandonment was primarily affected by temperature, slope, elevation, and river connectivity. Among them, the risk was positively associated with slope, elevation, and river connectivity and negatively associated with temperature. In conclusion, the Hani Rice Terraces were generally stable, with little risk of abandonment, and the factors affecting the risk of abandoned farming differed significantly in space.

Impact factors and production performance of adoption of green control technology: An empirical analysis based on the survey data of rice farmers in Sichuan Province

XIONG Ying, HE Peng

2020, 28(1): 136-146. doi: 10.13930/j.cnki.cjea.190673

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Abstract:
The application and promotion of crop green control technology addresses the urgent need for green agricultural development. However, existing researches on the adoption of green control technologies suffer from a lack of comprehensive analysis of the influencing factors and methods of production performance. A quantitative analysis of impact factors and production performance of the adoption of green control technology by rice farmers in Sichuan Province could provide policy directions to promote green control technologies and enrich our understanding of their application and promotion. Using data from a survey of rice farmers in Sichuan Province, a Logit model identified the main factors affecting adoption of green control technologies and estimated the propensity scores of production performance. DEA-PSM model analyzed the effects on production performance of the adoption of green control technology by farmers. The results showed that the male gender, higher education levels, greater planting area, cooperative membership, proximity to urban areas, green control technology training, ability to obtain a market premium for safe agricultural products produced by green control technology, consideration of the weak quality of agricultural ecological environments, and willingness to reduce pesticide use were associated with a greater likelihood of adopting green control technology. Rice production performance of the surveyed farmers was 0.103-1.000, and the average performance was 0.471. Without changing the technological level and input scale, there was still room for a 52.9% improvement in performance. Production performance of most farmers was between 0.4 and 0.6, and production efficiency was generally not high. The average rice production performance in Qionglai, Xuanhan, and Luxian counties was 0.558, 0.379, and 0.467 respectively, indicating significant differences among regions. The nearest-neighbor, radius, and kernel matching methods were applied to measure the effects of adoption of green control technology on rice production. The results showed that whether farmers adopting green control technology had little difference on production performance and the effect of farmer adoption of green control technology on rice production performance was not significant. Application and promotion of green control technology will therefore require the creation of a supportive external environment that empowers adoption of green control technology and focuses on reducing costs and increasing incomes.

Comprehensive evaluation of returning grazing lands to grasslands in a desertification control area based on the perspectives of farmers and herdsmen: A case study of Etuoke Banner, Inner Mongolia

CUI Yue, ZHAO Kai, ZHOU Shengqiang, HE Jing

2020, 28(1): 147-158. doi: 10.13930/j.cnki.cjea.190788

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Abstract:
To curb the accelerated degradation of natural grasslands in western China and promote ecological restoration, the Chinese government has encouraged the return of grazing lands to grassland since 2002. As both stakeholders and implementers of the technology for returning grazing lands to grasslands, farmers and herdsmen have important roles to play in adjusting and improving the technology for returning grazing lands to grasslands. In this paper, using micro-data on farmers and herdsmen in Etuoke Banner, Inner Mongolia, engineering techniques based on fence enclosure and management techniques that combine grass-fixing and seasonal grazing are used as evaluation objects along with an analytic hierarchy process and entropy weight method. The combination method includes an evaluation index system that includes five aspects:technical maturity, technical application difficulty, technical suitability, technical benefits, and technical promotion potential. From the perspective of farmers and herdsmen, the result of the comprehensive evaluation of the technology for returning grazing lands to grasslands was 0.469 8, indicating that the technology received an overall medium score by farmers and herdsmen, technical satisfaction was medium, and technical sustainability was considered weak. Farmers and herdsmen affirmed the degradation function of grassland ecosystems and the ecological benefit evaluation was considered high, while economic benefits and technology sustainability received a low score. The evaluation results followed the order of technical suitability > technical benefits > technical maturity > technical application difficulty > technical promotion potential. Regional differences in the comprehensive evaluation results were small. Many of the problems associated with the technology, if not appropriately resolved, will affect continuous and effective implementation, making achievements in returning grazing lands to grasslands difficult to consolidate. The comprehensive evaluation reflects the degree of satisfaction with the technology among farmers and herdsmen, and provides a reference for the continued effective implementation of the technology for returning grazing lands to grassland.

2020 Vol. 28, No. 1