Agricultural ecological

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Research Progress on Aquatic Plants & Epiphytic Microorganisms and Their Regulation on Fishery Environment

FAN Dingyue, XU Huimin, QIU Liping, LI Dandan, HU Gengdong, FAN Limin, SONG Chao, CHEN Jiazhang, MENG Shunlong

Chinese Agricultural Science Bulletin 2024, 40 (10): 159-164. DOI: 10.11924/j.issn.1000-6850.casb2023-0268

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The environmental and ecological problems have been widely concerned in fishery waters. At present, it has been found that aquatic plants and their epiphytic microorganisms play a significant role in the removal of pollutants in fishery waters, which are sustainable and efficient water quality regulation measure, and are widely used in the regulation of fishery environment. In this paper, the relevant research progress in recent years is reviewed from the perspectives of aquatic plant restoration methods, the interaction between aquatic plants and epiphytic microorganisms, and the role of aquatic plants and their epiphytic microorganisms in typical pollutants in fishery waters. The aim is to clarify the important role of aquatic plants and their epiphytic microorganisms in water quality regulation. We also hope to identify the current limitation of aquatic plant-epiphytic microbial ecological regulation methods and demonstrate the direction of improving these control methods, providing a better scheme for the water quality regulation of fishery environment.

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Effect of Nitrogen and Phosphorus Addition on Nutrient Content and Ecological Stoichiometry Characteristics of Wheat Soils in Loess Plateau

LI Zhiqiang, QI Peng, WANG Yazhi, WANG Xiaojiao, GAN Run, XUE Jianglong, LI Guoshan

Chinese Agricultural Science Bulletin 2024, 40 (10): 95-102. DOI: 10.11924/j.issn.1000-6850.casb2023-0365

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To investigate the effects of different nitrogen and phosphorus levels on total nutrient content, available nutrient content and ecological stoichiometry in agricultural soils, the authors analyzed the relationships between soil environmental factors, carbon (C), nitrogen (N) and phosphorus (P) content, and the ecological stoichiometry of total and available nutrients to elucidate the impact of different fertilizer levels on the dynamic balance of soil nutrients in agricultural fields. We selected spring wheat farmland soils in Loess Plateau as our research subject and conducted N and P addition experiments in 2017. The experimental treatments included a control group (CK), low nitrogen (LN), medium nitrogen (MN), high nitrogen (HN), low phosphorus (LP), medium phosphorus (MP) and high phosphorus (HP), totaling seven treatments. The results showed that: (1) nitrogen addition significantly increased the content of ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) in the soil, while phosphorus addition significantly decreased the NH₄⁺-N and NO₃^--N content (P<0.05). The addition of nitrogen and phosphorus nutrients had no significant effect on total nitrogen (TN) content (P>0.05). (2) N addition significantly increased soil C/N, C/P, N/P, C/AP and AN/AP ratios, and significantly decreased soil C/AN ratio (P<0.05). P addition significantly decreased soil C/N, C/P, N/P, C/AP and AN/AP ratios, and increased soil C/AN ratio (P<0.05). (3) Soil C/N and C/AN showed a significant negative correlation (P<0.05), while C/P and C/AP, N/P and AN/AP showed a significant positive correlation. In conclusion, available nutrient content and available ecological stoichiometry in agricultural soils in loess plateau region are more sensitive to N and P nutrient additions.

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Ecological Service Value of Oasis for Reducing Downwind Sandstorm: A Case Study of Oasis Farmland and Protective Forest in Jingdian Irrigation Area

ZHANG Jinghui, DONG Zhiyang, LIU Bin

Chinese Agricultural Science Bulletin 2024, 40 (7): 86-92. DOI: 10.11924/j.issn.1000-6850.casb2023-0243

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Sandstorm is one of the main natural disasters in agricultural production in the vast sandy areas of northwest China. To reveal the ecological function (ecological service value) of oasis farmland and shelterbelt in reducing downwind sandstorms, the paper took Jingtaichuan Irrigation District in Gansu Province as an example, and used the distance cosine formula to analyze the ecological service value of oasis ecological elements to reduce sandstorms in the downwind area. The results showed that the total ecological service value of farmland, shelterbelt, grassland, wetland and canal in the irrigation area was 62253.0×10⁴ yuan, within a range of 200 km in the downwind direction, the ecological service value of oasis farmland, shelterbelt, grassland and wetland in reducing downwind sandstorms was only 16.1% of the internal ecological service value of various ecological elements in the irrigation area. Due to the transmission characteristics of sandstorm, the transmission distance of ecological service value of farmland shelterbelt against sandstorm is much greater than that of windbreak and surface wind erosion protection. The distance cosine formula can better express the ecological service value of oasis farmland shelterbelt in reducing downwind sandstorm, with the increase of the distance and the increase of the angle with the main wind direction, the ecological service value of reducing the downwind sandstorm gradually decreases. The boundary of a sandstorm is blurry, and the maximum distance in the downwind area is an issue that needs further exploration.

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Status of Carbon Sequestration and Emission Reduction, Influencing Factors and Emission Reduction Measures in Typical Agro-ecosystem in China

WANG Jianwei, LI Dongxiao, WANG Hongguang, LI Haoran, WANG Qianyi, ZHANG Mingzhe, LI Ruiqi

Chinese Agricultural Science Bulletin 2024, 40 (6): 67-74. DOI: 10.11924/j.issn.1000-6850.casb2023-0242

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Agro-ecosystem is not only one of the important contributors to greenhouse gases, but also plays an important role in carbon sequestration and emission reduction. Under the background of “CO₂ emission peak” and “carbon neutrality”, agro-ecosystem has great potential for carbon sequestration and emission reduction. In this paper, we mainly reviewed the sources, fixed pathways, and influencing factors of main greenhouse gases in China’s typical agro-ecological types. Meantime, the specific contents were discussed including the existing research results, emission reduction potential and existing problems of carbon sequestration and emission reduction in agro-ecosystem. New research directions and exploration approaches were summarized to promote the research in the field of carbon sequestration in the entire agroecological system. It provided an important theoretical reference for China to further carbon sequestration and emission reduction, sustainable development of agriculture, and the realization of the “double carbon” goal as soon as possible.

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Potential Distribution of Bactrocera dorsalis Hendel in Sichuan Basin Based on Four Niche Models

ZHANG Xin, FENG Xiao, PEI Yue, WANG Rulin, ZHAO Jinpeng

Chinese Agricultural Science Bulletin 2024, 40 (5): 80-87. DOI: 10.11924/j.issn.1000-6850.casb2023-0202

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The purpose of this study is to provide scientific reference for the quarantine detection, comprehensive control and risk analysis of Bactrocera dorsalis Hendel in Sichuan Basin. Four niche prediction models, i.e. Maxent, GARP, Bioclim and Domain were used to predict the areas of potential distribution of B. dorsalis in Sichuan Basin. The results of different models were analyzed and compared using two statistical criteria: the area under the receiver operating characteristic curve (AUC) and Kappa value. The AUC average values of the four models are all above 0.9 and the Kappa average values are above 0.75, indicating that the prediction model has high prediction accuracy. Furthermore, the paper shows that precipitation of the driest month, mean temperature of the wettest quarter, temperature seasonality and mean diurnal range are the key environmental variables that dominated the potential distribution of B. dorsalis, which play a decisive role in the formation of the current distribution of B. dorsalis. The suitable areas and locations of B. dorsalis predicted by four models are quite different, but they all contain the hilly area in central Sichuan Basin, the parallel rank-valley area in eastern Sichuan Basin and the low mountain area in southern Sichuan Basin. The highly and moderately suitable areas are concentrated in the east of the hilly area in central Sichuan Basin, the west of the parallel rank-valley area in eastern Sichuan Basin and the low mountain area in southern Sichuan Basin. It can be seen that the suitable areas of B. dorsalis in Sichuan Basin is wide. In view of the economic importance of citrus to Sichuan Basin, the local relevant departments should strengthen the detection and quarantine work of B. dorsalis to avoid large losses.

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Analysis of Variation Characteristics of Ecological Net Primary Productivity and Climate Response in Hulun Buir Agricultural Reclamation Group

QU Xuebin, JIANG Fengyou, GAO Shaoxin, XIN Xiaofei

Chinese Agricultural Science Bulletin 2023, 39 (32): 109-114. DOI: 10.11924/j.issn.1000-6850.casb2022-0903

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To provide technical reference for the carbon source / sink analysis of farmland ecosystem, the ecological net primary productivity (Net ecosystem productivity, NEP) of Farm of Agricultural Reclamation Group in Hulun Buir was evaluated from 2001 to 2021. The NEP of various farms was studied based on remote sensing and meteorological data. The change trend and the response to climate of NEP were analyzed by using Sen trend line analysis method, Hurst index, coefficient of variation method and partial correlation analysis method. The results showed that the annual average NEP of Hulun Buir was 221.1 g C/(m·a), decreasing to the both sides of the Daxing'an Mountains. There was extremely significant increase of NEP during the study period. However, the results of Hurst index analysis showed that NEP changes of most farms of Hulun Buir Agricultural Reclamation Group were negatively associated with previous, namely decreasing trend in the future. The correlation between the NEP of Hulun Buir Agricultural Reclamation Group and precipitation was significant positive, but insignificant with temperature. It is suggested that Hulun Buir Agricultural Reclamation Group should strengthen the promotion of farming methods with high carbon fixation capacity to prevent the decline of carbon fixation capacity of farmland ecosystem, and strengthen the construction of agricultural irrigation and weather modification capacity to reduce the risk and impact of farmland drought disasters.

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Effect of Quota-based Fertilization on Soil and Ecological Environment: Research Progress

YANG Dong, LIU Xiaoxia, CHEN Hongjin, YU Yijun

Chinese Agricultural Science Bulletin 2023, 39 (32): 91-98. DOI: 10.11924/j.issn.1000-6850.casb2023-0384

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Quota-based fertilization is a crucial measure for improving soil quality and ensuring food security. Under the policy backdrop of reducing fertilizer usage and promoting agricultural green development, the systematic exploration of the impact and inherent regulatory mechanisms of quota-based fertilization on soil and the ecological environment, as well as the summary of key technologies for protecting and enhancing cultivated land quality, can contribute to an objective evaluation and comprehensive understanding of the significant role of quota-based fertilization in improving cultivated land quality. This article reviewed the connotation and policy evolution of quota-based fertilization, along with its technological innovations. It also summarized the effects and regulatory mechanisms of quota-based fertilization on key indicators of soil quality, discussed how to enhance soil quality through quota-based fertilization measures, and proposed future research priorities for quota-based fertilization in soil quality protection, to provide references for further promoting the improvement of cultivated land quality at a deeper level.

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Carbon Footprint and Characteristics of Farmland Ecosystem in Yunnan Province

KUANG Xueqin, XIE Bin, LI Yunchun, LI Jing

Chinese Agricultural Science Bulletin 2023, 39 (32): 99-108. DOI: 10.11924/j.issn.1000-6850.casb2022-0973

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Based on the “Provincial Greenhouse Gas Preparation Guidelines (Trial)”, the characteristics of carbon emission equivalents, carbon sinks and carbon footprints of farmland ecosystems in Yunnan Province in 2008 to 2020 were studied, and the main measures for reducing carbon sequestration in future agricultural development were proposed. Based on the data related to production inputs and crop yields in Yunnan Province from 2008 to 2020, the carbon footprint analysis method was applied to systematically analyze the carbon emissions and carbon sequestration of farmland ecosystems in Yunnan Province. The results showed that the small amount of greenhouse gas emissions such as CH₄and N₂O from farmland ecosystems should not be ignored, and the direct carbon emissions, carbon equivalent emissions of nitrous oxide and carbon equivalent emissions of methane from farmland ecosystems became the three most important factors of greenhouse gas emissions from farmland. On the other hand, the carbon equivalent emissions of greenhouse gases in Yunnan Province increased year by year from 2008 to 2017, and then showed a decreasing trend year by year. The carbon equivalent emission intensity showed fluctuating changes, among which straw burning, fertilizer degradation and diesel combustion were the main direct carbon emission sources, and N₂O and CH₄ were the main carbon equivalent emission sources; the carbon absorption intensity showed fluctuating changes, and the carbon absorption of maize and sugarcane were much higher than that of other crops, which was the main source of carbon sequestration; vegetables and melons had certain potential to increase sinks, and crops had a tendency to change from food crops to cash crops; the carbon footprint showed a trend of increasing and then decreasing, and was basically positively correlated with the trend of carbon emission equivalent. The average annual growth rate of carbon emission equivalent and carbon sequestration of agricultural ecosystem in Yunnan Province from 2008 to 2020 was 0.98% and 1.78%, respectively. The carbon footprint had not yet reached the limit of regional ecological carrying capacity, and the ecological carbon surplus had improved from 2017 to 2020, but the current ecological carbon surplus situation was still more severe. Finally, it is concluded that straw recycling, precise fertilization and the development of low carbon and high yield seed industry will be the main measures to control agricultural carbon emissions in Yunnan Province in the future.

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Effects of Straw Returning on Soil Ecology and Crop Growth and Development

GAO Jun, WANG Huiquan, GU Dongxiang, ZHANG Simei, ZHANG Chuanhui, GU Kejun

Chinese Agricultural Science Bulletin 2023, 39 (30): 87-93. DOI: 10.11924/j.issn.1000-6850.casb2022-0897

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Crop straw is rich in nutrients and has high utilization value. As an efficient and low-cost way to utilize straw resources, straw returning plays a crucial role in maintaining soil fertility cycle and sustainable agricultural development. In this paper, the effects of straw returning on soil temperature and humidity, soil physical and chemical properties, soil enzyme activity, crop root system and crop above ground were reviewed, the mechanism of the effects of straw returning was analyzed, and the negative effects of straw returning on crop growth pointed out. Based on this, some key research directions in the future were put forward, such as establishing an optimization model for straw returning, strengthening the research on reducing obstacles of straw returning, and developing new disposable special fertilizers for rice and wheat straw returning.

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Analysis of the Current Research Status of Wetland Ecosystem Service Functions Based on Web of Science

WANG Mingyu, WENG Xiaohong, SONG Yu, HE Xin, ZENG Xiannan, SUI Xin

Chinese Agricultural Science Bulletin 2023, 39 (29): 137-145. DOI: 10.11924/j.issn.1000-6850.casb2023-0053

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This study used bibliometric analysis to investigate the research status, hotspots, and trends of wetland ecosystem service functions on a global scale by using literature published between 2002 and 2022 in the Web of Science core database. VOS viewer software was employed to conduct bibliometric and visualization analysis on the publication volume, countries, core authors, research institutions, and research hotspots of wetland ecosystem service function research. The results showed that the number of papers published in the field was generally increasing; the United States and China are the two countries with the highest number of papers published in the field; the Chinese Academy of Sciences and the USGS are the research institutions with the highest number of papers published; a grouping of high-frequency keywords identifies the research hotspots as “Benefit”, “Soil”, “China”,and “Marsh”, which are closely related to wetland ecosystem services and provide a variety of research directions for the future development of the field. This study provides a reference for relevant researchers in the research trend and future research hotspots of wetland ecosystem services.

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Reserve Cultivated Land Resources and Ecological Risk Assessment in 2021: Taking Danjiangkou City as an Example

SUN Pei, ZHOU Lingyun, YI Jiewei, ZHANG Chi, WANG Wenwen, YIN Wei

Chinese Agricultural Science Bulletin 2023, 39 (29): 68-73. DOI: 10.11924/j.issn.1000-6850.casb2022-0899

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To implement the strictest farmland protection system and further standardize the balance management of arable land occupation and compensation, Danjiangkou City had carried out the survey and evaluation of arable land reserve resources in the whole region. Taking the base map data of farmland reserve resources survey and evaluation in Danjiangkou City issued by Hubei Province as the research object, according to the evaluation criteria in the “Work Plan for the Survey and Evaluation of Cultivated Land Reserve Resources in Hubei Province” (EZZB [2021] No.15), the evaluation of farmland reserve resources in Danjiangkou was carried out, and further risk assessment was carried out on the plots that were evaluated as suitable for cultivation. The evaluation results showed that the total suitable arable land area of the survey and evaluation of cultivated land reserve resources in Danjiangkou City was 106.5 hm², accounting for 43.15% of the area of the assessment base map. Among which 56.2 hm² was grassland and 50.3 hm² was bare land. The areas suitable for cultivation were at or below the middle risk, and the area of low risk was only 4.9 hm², accounting for 1.97% of the area of the assessment base map. The area of lower risk was 74.5 hm², accounting for 30.18% of the area of the assessment base map. The area of medium risk was about 27.1 hm², accounting for 10.99% of the area of the assessment base map. The reserve cultivated land in Danjiangkou City had a large area with medium ecological risk, which was mainly distributed around the reservoir area of the South-to-North Water Diversion Project, and required appropriate ecological protection and restoration.

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Construction of Compound Ecological Forest Network in Main Grain Producing Areas of Plain

CHEN Benxue, GOU Rongxin, WU Ruining, LI Yanbing

Chinese Agricultural Science Bulletin 2023, 39 (28): 1-6. DOI: 10.11924/j.issn.1000-6850.casb2022-0774

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Through investigation and analysis of the landscape quality and ecological function of farmland protective forest network in eastern Henan Plain, it was found that there were some problems such as broken forest network structure, single tree species and lack of management. In view of the problems existing in farmland protective forest in the eastern Henan Plain, adhering to the plant application principle of "high protection, strong adaptation, low management, large grid", the quality of farmland forest network in the main grain producing areas of the plain is improved from the following four aspects: (1) build water conservation forest, form a complex water forest space; (2) improve the forest quality around the village and display the rural characteristics; (3) construct the framework of forest network to enrich the public space; (4) connect the veins of forest network and maintain ecological balance. The paper aims to help form both functional and landscape ecological complex forest network, and to provide reference for the construction of regional farmland shelter forest.

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Analysis of Soil Nutrient Changes and Ecological Stoichiometry Under Different Land Use Types

LI Xuemei, SHU Yingge

Chinese Agricultural Science Bulletin 2023, 39 (28): 62-69. DOI: 10.11924/j.issn.1000-6850.casb2022-0827

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To study the characteristics of soil nutrients and the ecological stoichiometric ratios of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) under different land use types, the distribution of soil nutrients in the surface layer (0-20 cm) of paddy fields, drylands, grasslands and woodlands and the differences were analyzed by bibliometric methods. The results showed that the four land use types were relatively rich in total potassium and fast-acting potassium, but generally deficient in total phosphorus, with significant differences (P<0.05); soil total nitrogen was positively significantly correlated with total phosphorus (P<0.05), and negatively significantly correlated with adequate phosphorus (P<0.05), soil organic matter showed a highly significant positive correlation with total nitrogen (P<0.01), and total soil phosphorus showed a highly significant positive correlation with total potassium (P<0.01). Soil C:N values were highest in paddy fields, soil C:K, C:P and N:K values were highest in grasslands, N:P values were highest in woodlands and P:K values were highest in drylands; based on the integrated soil nutrient pool index, it could be concluded that the overall soil nutrient levels of the four different land use types showed paddy fields>grasslands>drylands>woodlands. The four land use types effectively presented the differences between soil nutrient content and ecological stoichiometric ratio of elements, which could provide theoretical support for the revegetation and soil improvement of different land-use types.

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Distribution Characteristics of Soil pH in Cultivated Land in Qinling-Bashan Area and Its Influencing Factors

GAO Peng, YANG Xiaomin, LI Danni, YU Zhengjun, YAO Yuan, SI Hua

Journal of Agriculture 2023, 13 (8): 32-36. DOI: 10.11923/j.issn.2095-4050.cjas2022-0140

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To explore the distribution characteristics of soil pH of cultivated land in Qinling-Bashan area, this study took Hanzhong City in Shaanxi Province as the research area, and analyzed the distribution law of soil pH in cultivated layer and its influencing factors by geostatistical and GIS methods. The results showed that the regional soil pH was between 4.15 to 8.41, with an average value of 6.50, and the overall soil was weakly acidic to neutral. The spatial distribution of soil pH showed the characteristics of low in the middle and high in the east and west. The distribution of soil pH in this area was affected by both structural factors and human factors. The results of geostatistical analysis showed that the optimal theoretical model of the soil pH variation was the exponential model, and the nugget effect value was 0.366, which indicated that the spatial heterogeneity of regional variables was the result of the joint action of random factors and structural factors, among which the soil type, farming system, soil parent material and altitude were the main influencing factors. This study could provide a theoretical basis for rational utilization of cultivated land and sustainable agricultural development.

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Effects of Continuous Straw Returning on Rice Yield and Nitrogen Utilization

MENG Ruoxi, WANG Xiaoli, DUAN Jianjun, XU Bin, YANG Hongwei, MEI Tingting

Journal of Agriculture 2023, 13 (8): 37-45. DOI: 10.11923/j.issn.2095-4050.cjas2022-0113

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To clarify the impact of straw returning ratio on rice yield and nitrogen utilization, a field plot positioning experiment was conducted in Tangtou Town, Sinan County of Guizhou Province during the rice growing season from 2019 to 2021. Six treatments were set up in the experiment: CK was no fertilizer, S₀ was conventional fertilizer, S₁ was conventional fertilizer + straw returning 5 t/hm², S₂ was conventional fertilizer + straw returning 10 t/hm², S₃ was conventional fertilizer + straw returning 15 t/hm², and S₄ was conventional fertilizer + straw returning 20 t/hm². The results showed that from 2019 to 2021, the yield of S₃ treatment was the highest, increased by 20.16%, 8.66% and 14.40% respectively compared with that of S₀ treatment, and the yield increase in 2019 was the highest. The reason for the yield difference was that straw returning to field improved the number of effective panicles, the number of grains per panicle, 1000-grain weight and seed setting rate of rice, and then significantly increase the yield. The fitting analysis of straw returning and rice grain yield showed that the highest grain yield was achieved by straw returning amount of 15.43 t/hm². Straw returning could improve the nitrogen partial factor productivity and nitrogen harvest index between years. In 2019, the nitrogen partial factor productivity of S₃ treatment was the highest, while the nitrogen harvest index of S₄ treatment was the highest, which were 42.81% and 24.30% higher than those of S₀ respectively. In 2020, the nitrogen partial factor productivity and nitrogen harvest index of S₃ treatment were the highest, with an increase of 55.98% and 22.61% over those of S₀ treatment respectively; and in 2021, the nitrogen partial factor productivity and nitrogen harvest index of S₃ treatment were also the highest, with an increase of 21.75% and 15.88% over those of S₀ treatment, respectively. Straw returning increased the physiological utilization rate of nitrogen between years, and S₃ treatment had the best effect, with an increase of 72.97%, 76.14% and 52.98% respectively compared with that of S₀ treatment from 2019 to 2021. Moreover, year and straw returning treatment significantly improved the physiological utilization rate of nitrogen and agricultural efficiency of nitrogen. Therefore, considering rice yield, straw returning fitting results and nitrogen utilization rate, S₃ treatment is more suitable for straw returning.

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Impacts of Various Tree Species on Spatial Heterogeneity of Soil Dissolved Organic Carbon in Forest Ecosystems

KONG Lingqian, LIU Xianbin, LI Yun

Journal of Agriculture 2023, 13 (8): 46-55. DOI: 10.11923/j.issn.2095-4050.cjas2022-0112

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To investigate the contents of soil dissolved organic carbon and soil organic carbon in the rhizosphere of several tree species in different sampling places in a forest ecosystem, the factors affecting the spatial heterogeneity of soil dissolved organic carbon and soil organic carbon in forest ecosystem were analyzed. This project was carried out in the subtropical montane moist evergreen broad-leaved primary forest ecosystem in Ailao Mountains of Yunnan Province. Seven dominant tree species in the primary soil area of forest ecosystem with high altitude in three sampling watersheds were selected as the research objects to investigate the contents of soil dissolved organic carbon and soil organic carbon in the 0-10 cm topsoil. The results showed that the contents of soil dissolved organic carbon and soil organic carbon in the rhizosphere of 5 tree species, including Lithocarpus hancei (Bentham) Rehd., Castanopsis rufescens (Hook. f. et Thoms.) Huang et Y. T. Chang., Lithocarpus xylocarpus (Kurz) Markg., Symplocos ramosissima Wall. ex G. Don and Schima noronhae Reinw. ex Bl. Bijdr, were significantly higher than those in the rhizosphere of the other 2 shrub species, namely, Camellia forrestii (Diels) Coh. St. and Vaccinium duclouxii (Levl.) Hand.-Mazz.. Among the 5 tree species, the contents of soil dissolved organic carbon and soil organic carbon in the rhizosphere of L. hancei and S. noronhae were significantly higher than those of the other 3 species, indicating that different tree species could apparently affect the spatial heterogeneity of soil dissolved organic carbon and soil organic carbon. The contents of soil dissolved organic carbon and soil organic carbon as well as the proportion of soil dissolved organic carbon in soil organic carbon in the rhizosphere of the 7 sampling tree species respectively reached the maximum value in the Laojunshanshen watershed, and decreased to the corresponding lowest value in the Sankeshu watershed, indicating that the environmental factors in different sampling watersheds could also obviously affect the contents of soil dissolved organic carbon and soil organic carbon as well as the ratio between them. The research results of this project fully proved the complexity of the spatial distribution of soil dissolved organic carbon and soil organic carbon in forest ecosystems and the diversity of environmental controlling factors, and could provide new scopes for the research on soil organic carbon composition and carbon storage in various types of forest ecosystems in the world.

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Agricultural Mulching Film in Shiyan: Application Status and Pollution Control Countermeasures

WANG Xiaoxi, SONG Yingran, HUANG Xiaoshan, LI Tao, TANG Ran, HE Jian, LI Hui, LIN Shan

Journal of Agriculture 2023, 13 (8): 56-62. DOI: 10.11923/j.issn.2095-4050.cjas2022-0092

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At present, the application of plastic mulching film in agricultural production, such as the using amount, the mulching area and the mulching crop species, has increased year by year in Shiyan, causing a large amount of mulching film residues and serious pollution to agricultural environment. Based on statistical data and the actual situation, it can be seen that the prevention and control of agricultural mulching film residue pollution and the application of new type of mulching film have become an urgent task, which is of great significance to environmental protection and agricultural development in Shiyan. The study analyzed current situation of agricultural mulching film application and problems in film recycling in Shiyan, and put forward corresponding countermeasures and suggestions, aiming to provide reference for the prevention and control of mulching film pollution in the area.

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Study on Cultivated Land Quality Level in the Upper Reaches of Xiangjiang River Hilly Region based on AHP and GIS: Take Dong’an County as an Example

LI Xiaoqing, WU Lin, HE Changyuan

Chinese Agricultural Science Bulletin 2023, 39 (23): 30-38. DOI: 10.11924/j.issn.1000-6850.casb2022-0873

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Cultivated land is the basis of food production, and the quality of cultivated land affects the comprehensive production capacity of cultivated land. The central and local governments have repeatedly pointed out the need to protect the red line of cultivated land and to stabilize the policy, area and yield of grain production. The area of mountainous and hilly areas in the Xiangjiang River basin is widely distributed, and it is important to study the quality level of cultivated land in mountainous hilly areas to deepen the protection of cultivated land and improve the land productivity of cultivated land in the basin. The cultivated land in Dong'an County, a typical mountainous and hilly area in the upper reaches of the Xiangjiang River basin, was selected for quality evaluation. The results were analyzed by overlaying the soil map, current land use map and administrative division map of Dong’an County on the ArcGIS platform. The index weight was determined by hierarchical analysis, and the affiliation degree was determined by fuzzy mathematics, after the comprehensive weights were derived. The results showed that according to the evaluation standard of “quality grade of cultivated land” GB/T 33469—2016, the evaluation result was that the quality of cultivated land in Dong’an County was divided into 6 grades. Among them, the area of the third grade was 12793 hm², accounting for the highest proportion of the total area, which was 37.4%; followed by the wide distribution area of the second grade and the fourth grade, which were 8648 hm² and 6985 hm², respectively, accounting for 25.3% and 20.4%; the area of other grades of land was relatively small. The content of effective phosphorus, fast-acting potassium and organic matter of cultivated land in Dong’an County was mostly at the middle level, and the area of cultivated land with soil nutrient characteristics of Grade I, Grade II and Grade III was widely distributed, which required some targeted measures to enhance the production capacity of cultivated land.

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Diversity of Fungi in the Rhizosphere Soil of Phragmites australis in the Sandy Land and Saline-alkali Land at the Southern Margin of the Badain Jaran Desert

XIONG Jianzhou, QI Yake, LI Chaozhou, JIAO Jian

Chinese Agricultural Science Bulletin 2023, 39 (23): 45-54. DOI: 10.11924/j.issn.1000-6850.casb2023-0089

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The fungal diversity and its relevant influencing factors of reed rhizosphere soil in sandy land and saline-alkali land at the southern margin of Badain Jaran Desert were studied. Typical sandy land and saline-alkali land were selected at the edge of desert in Linze County, Zhangye City, Gansu Province, and the soils from four quadrates were collected (reed rhizosphere soils in saline-alkali land noted as YL, bare area soil in saline-alkali land noted as YD, reed rhizosphere soils in sandy land noted as SL and bare area soil in sandy land noted as SD) as experimental materials, determination and analysis of the soil fungal diversity in various plots was carried out by using high-throughput sequencing technology. The results showed that the fungal abundance of the soils in sandy lands was significantly higher than that in saline-alkali lands. Ascomycota and Basidiomycota were the dominant phyla in common in the soils of all quadrates, among which Ascomycota was the first dominant phylum, Basidiomycota was the second, and Hair follicle was the third dominant phylum, while Olpidiomycota existed only in YL, which was the fourth dominant bacterial phylum. The species diversity of fungal community was YL>YD>SL>SD; the order of fungal community uniformity was YL>YD>SD>SL, indicating that fungal species were the most balanced in YL, and fungi dominant species had the highest proportion in all fungi in SL. The composition of fungal communities in each soil of the quadrates was highly specialized, and the dominant flora differed significantly in different quadrates; Relevant analysis also showed that the soil water content was YL>YD>SL>SD, soil available phosphorus content and electrical conductivity were YD>YL>SD>SL; canonical correlation analysis (CCA) showed that nutrient factors and soil enzyme activities were related to soil microbial abundance significantly, and soil alkaline-hydrolyzed nitrogen content and pH value had the most significant effects on fungal communities. The inter-root distribution of reed can effectively improve the physicochemical properties and microbial community structure of saline and sandy soils.

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Temporal and Spatial Changes of Precipitation in the Growing Season of Natural Grass in Guoluo from 1961 to 2016

JIA Xuzhi, CAI Zhongzhou, XIANG Wen, DOU Hua

Chinese Agricultural Science Bulletin 2023, 39 (23): 77-81. DOI: 10.11924/j.issn.1000-6850.casb2022-0724

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To reveal the temporal and spatial variation characteristics of precipitation in forage growing season and the relationship between precipitation and natural forage growth, and between precipitation and drought and flood in Guoluo of Qinghai, we used a method which is advanced and simple to conduct the study. The results showed that: (1) the main precipitation periods in Guoluo were divided into 1961-1969, 1970-1979, 1980-1991 and after 1992; from the perspective of space, the precipitation showed an obviously decreasing trend from southeast to northwest, the maximum precipitation amount was in Jiuzhi and the minimum was in Maduo; the maximum precipitation amount was 2.3 times of the minimum; and the precipitation in the central areas of Guoluo was close to the average value of the maximum and the minimum; (2) there was a significantly positive correlation between forage yield and average temperature and precipitation, and a significantly negative correlation between forage yield and sunshine hours; (3) the stage significantly higher than the PCD (precipitation concentrated degree) trend line coincided with the high-frequency period of rainstorm and flood, and the stage significantly higher than the PCP trend line coincided with the high-frequency period of drought.

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