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Yang G.,Beijing Academy of Agriculture and Forest science | Yang G.,Beijing Normal University | Shi Y.,Beijing Academy of Agriculture and Forest science | Xu Q.,Beijing Academy of Agriculture and Forest science
Sensor Letters | Year: 2013

Radar data has important implications in agricultural fields monitoring, particularly in the retrieval of the crop height, leaf area index (LAI) and soil moisture information. The objective of this study was to estimate soil moisture contents based on RADARSAT-2 synthetic aperture radar (SAR) data acquired over wheat fields. The soil moisture inversion algorithm was based on semi-empirical backscattering models and the prior estimation of wheat heights (h) and wheat water contents (WC) from RADARSAT-2 data. The co-polarized correlation coefficient (Pvvhh and the ratio of the absolute value of the cross polarization to the crop height (Avh were analyzed with respect to variations in wheat height and wheat water content. Furthermore, Landsat5 TM data were used to classify the planted wheat area. The results showed average relative errors of 14%, 32% and 24% for the retrieval of wheat height, wheat water content and soil moisture, respectively. Copyright © 2013 American Scientific Publishers.


Liu X.,China Agricultural University | Li X.,Ministry of Land and Resources | Sun D.,China Agricultural University | Li H.,Beijing Academy of Agriculture and Forest Science | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

The characteristices of farmland site are complicated and versatile affected by many factors in urban fringe. Extract farmland and its corridor landscape types using high resolution remote sensing image is a superior way to detect farmland change. It is significant for farmland protection and delineation of basic farmland to analyze the relationship between farmland and its corridor landscape types. Taking Daxing district of Beijing as a case, object-oriented classification approach was adopted to extract farmland and other landscape types from SPOT5 remote sensing image in year of 2004 and 2007, including transport land, river, hydraulic construction land, irrigational land, farmland shelterbelt. The extracted road width was also evaluated. Finally, quantitative changes and spatial distribution changes of the 5 corridors during 4 years simply were analyzed through methods of corridor analysis of landscape ecology and GIS spatial analysis. The results showed that the classification accuracy and Kappa coefficient were more than 90% with visual interpretation, and the width of road was from 4 to 70 m; Farmland shelterbelt suffered the most obvious quantitative changes, and became scattered. Agricultural irrigational land distributed evenly. Secondary class road took greater changes, which mainly distributed in the northern study area affected greatly by urbanization and industrialization. Therefore, the object-oriented classification approach can take full advantage of class-related features, which fuses class site information at different levels. The spatial distribution of corridors and farmland shows a certain correlation, that is, the higher density of farmland shelterbelt and agricultural irrigational land, the smaller loss probability of farmland; the higher density of transport land, the higher loss probability of farmland.


Zhang W.W.,Beijing Academy of Agriculture and Forest Science | Li H.,Beijing Academy of Agriculture and Forest Science
Advanced Materials Research | Year: 2013

Quantifying agricultural non-point pollution load accurately and understanding contribution of the pollution sources clearly is the base how to control non-point source pollution effectively. Pollution loads from agricultural non-point source in the upper Lianghuai basin of Huairou Reservoir, including Huaisha River and Huaijiu River basin, were estimated according to export coefficient modeling. The results show that total nitrogen and total phosphorus loads in Lianghuai basin respectively are 322.52 t and 35.769 t in 2011.The total nitrogen and total phosphorus load intensities in Huaisha River basin are higher than that in Huaijiu River basin. Farmland planting including orchard and cropland, livestock and poultry breeding and rural domestic waste make a greater contribution to total nitrogen and total phosphorus loads. The study can provide scientific basis for further understanding characteristics of the nitrogen and phosphorus loads and agricultural structure adjustment. © (2013) Trans Tech Publications, Switzerland.


Dong S.,Beijing Academy of Agriculture and Forest Science | Li X.,Ministry of Land and Resources | Li H.,Beijing Academy of Agriculture and Forest Science | Sun D.,China Agricultural University | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

Cultivated land, as an important agricultural resource, being quickly and accurately extracted using remote sensing is the key step for its protection and sustainable use. An approach was presented based on multiscale fractal signature and image threshold segment to cultivated land extraction from ETM+ remote sensing images. The blanket method used for computing fractal dimension of surface was modified to calculate fractal dimension of curves including the ″up″ and ″down″ fractal signatures at each scale based on the spectral curve of each pixel. The computed fractal signatures of the cultivated land and other land covers at corresponding scale were analyzed and compared; The results showed that cultivated land was enhanced through differencing between the third and fourth down fractal signature, and its spatial distribution was further extracted using image segmentation. The segmentation area accuracy and point positioning accuracy were as high as 91.0% and 71.8%, respectively. The point positioning accuracy of the rainfed cultivated land was relatively low, while irrigated cultivated land and vegetable land were up to 86.6%. The method developed in the study can effectively extract cultivated land and provide a reference for further related researches.


Liu T.,China Agricultural University | Li H.,Beijing Academy of Agriculture and Forest Science | Sun D.,China Agricultural University | Zhou L.,Beijing Academy of Agriculture and Forest Science
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2010

Land management right transfer is another significant farmland innovation after the Household Contract Responsibility (HCR) system. It has profound environmental and socioeconomic impacts on our complex society, and relevant research has been increased rapidly during the past decade. These researches mainly involve the policy's impacts on society, economy and its mechanism. However, as far as we know, the effect of this innovation on landscape is poorly understood. In fact, the relationship between land rights and landscape has been concerned by abroad scholars in recent years. Since the importance of innovation's effect on landscape at patch level, our study would provide valuable information for policy establishment. In this article, we take Changping district of Beijing as a case, and categorize the rural productive land into three right types as first level landscape and ten land-use types as second level landscape. The right types are Family type, Rental type and Collectivity type respectively. Family type means that farmer gets the right by land allotment of rural community. Rental type means that Farmer or economic organization gets other farmers' rights by exchange, tenancy or other ways. Collectivity type means that collective organization gets the right by reserving partial land in the process of land allotment of rural community. Based on extracting boundaries of land patches partitioned by rights, we analyzed landscape characteristics of the three land right types and their land-use types respectively by calculating several patch-level landscape metrics. The results show that land management right transfer is subjected to developed areas, where land-use structure is transformed from dominant crop land to various land-use types. Although the patch-level operation scale of agricultural land has increased, a large amount of construction land also leads to fragmentation of regional landscape. Land patches present relatively square shape, however, narrow patches still account for a large proportion in crops land. Furthermore, patches of construction land present mosaic pattern, while the degrees of connected patches of agricultural land-use types remain relatively low. Based on the results, although land transfer enhanced the agricultural land use intensity, non-crop land also imperiled the food security of the region. In addition, construction land patches lead to fragmentation of farmland landscape. As a consequence, it weakened the ecological effect of farmland landscape and increased the risk of environmental pollution. The original intention of this reform is to solve the performance bottlenecks of agricultural production under the HCR system, but our results show that there is a gap between effects of policy enforcement and the goal. So for the future policy optimization and regional ecosystem management, first, we suggest that the government should avoid further fragmentation on the family right type and make collective organizations full guide the land transfer, especially, in the region where the economy and location conditions are relative backward. Second, for the non-crop land use tendency after transfer, besides strengthening land use supervision, government and collective organization should actively support big farming household and impel the connected patches transfer. Last, the government should establish corresponding system of environmental assessment and avoid agricultural land, especially, crop land to be contaminated by industry and recreation activity around.


Sun D.,China Agricultural University | Wang Y.,China Agricultural University | Li H.,Beijing Academy of Agriculture and Forest Science | Zhang W.,China Agricultural University | Zhou L.,Beijing Academy of Agriculture and Forest Science
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2010

Regional agricultural ecological system faces more and more environmental pressure with bigger fertilizer input and higher land and water resources use efficiency. In order to assess the environmental risk of fertilizer overuse, the spatial data of fertilizer input is necessary. This paper firstly analyzed the structures of land primary productivity and the major limiting factors in theory, then adopted principal component analysis to quantify the spatial relationship between the 8-day composite MODIS NDVI time series of different cropping patterns and regional land natural quality, also its relationship with fertilizer input, finally designed the spatializing method of the regional statistical fertilizer input. The results showed that the first principal component of the 8-day composite MODIS NDVI time series under different cropping patterns was closely correlated with land natural quality, and their second principal component significantly related to chemical fertilizers input. Therefore, this paper spatialized the community-level statistical chemical fertilizer input in proportion with the second principal component, and concluded that the principal component analysis of the 8-day composite MODIS NDVI time series under different cropping patterns could discern the productivity disparity from land quality and human beings inputs such as fertilizer input, thus the rationality and feasibility of the spatializing method were clarified.


Zhang W.,Beijing Academy of Agriculture and Forest Science | Wu P.,China Agricultural University | Li H.,Beijing Academy of Agriculture and Forest Science | Sun D.,China Agricultural University | Zhou L.,Beijing Academy of Agriculture and Forest Science
Procedia Environmental Sciences | Year: 2011

Taking the Landsat TM and ASTER images of Hanshiqiao wetland nature reserve in 1988, 1996 and 2004 as data source, based on the landscape types from imagery classification, the reserve landscape pattern and its changes were analyzed, meanwhile, the landscape quality and its changes were evaluated and discussed. Several landscape pattern indices were analyzed, the results indicated that from 1988 to 2004, as the result of natural factors and human disturbances, the landscape structure has been changed, landscape fragmentation has become more and more serious, patches have been tended to regular shape, and connectivity of the natural wetland has been weakened. In addition, the landscape quality was evaluated based on the indicators of pressure, state and response. The results showed that during 1996-2004 periods, the landscape quality for Hanshiqiao wetland nature reserve has degraded obviously, which was mainly influenced by human activities breaking into wetland landscape. Effective wetland management and control is therefore needed to solve the issues of the wetland loss and degradation in Hanshiqiao wetland nature reserve. © 2011 Published by Elsevier Ltd.


Dong S.,Beijing Academy of Agriculture and Forest Science | Sun D.,China Agricultural University | Zhang W.,Beijing Academy of Agriculture and Forest Science | Li H.,Beijing Academy of Agriculture and Forest Science | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

Professional decision-making models and technology methods were developed to solve practical problems in agricultural resources and environment based on Beijing suburban natural resources and socio-economic information management platform, and they were completed the initial integration with the platform, and a space integrated management which combined Beijing agricultural resources qualitative analysis, quantitative calculation with visual display was achieved. Firstly, structure and decision application interactive implementation of decision application system module were introduced. Secondly, Beijing agricultural resource use decision-making models and technology and its preliminary application results were elaborated based on synthetic management platform. Finally, synthetic management platform future works were pointed out from professional decision model integrated methods, normalization and standardization, and security system. After four years of construction and operation, decision-making module based on platform system has been initially applied in Beijing agricultural and rural related businesses supporting management, and it is very great significant for Beijing new socialist countryside construction and rural three agricultural development.


Zhang W.,Beijing Academy of Agriculture and Forest Science | Li H.,Beijing Academy of Agriculture and Forest Science | Sun D.,China Agricultural University | Zhou L.,Beijing Academy of Agriculture and Forest Science
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

Increased nutrient (i. e., nitrogen and phosphorus) concentrations have been observed in the surface water bodies inmany counties. Agricultural non-point source (NPS) pollution has been identified as one of the most important factors in causing water quality deterioration. To control NPS pollution effectively, it is necessary to quantifying agricultural pollution loads and understanding contribution of the pollution sources. Furthermore, watershed-based analysis can provide scientific basis for agricultural practices and water pollution control. In this paper, the general export coefficient model was used to estimate the loads of total nitrogen (TN) and total phosphorus (TP) from the upper Lianghuai basin of Huairou Reservoir for year 2000 and 2011. The model results showed that the total nitrogen and total phosphorus loads in 2000 were mainly contributed from the farmland planting, livestock and poultry breeding., while aquatic agriculture mainly contributed the total nitrogen and total phosphorus loads in 2011.Agricultural nitrogen and phosphorus loads increased in the study area during two year period. The nitrogen load increased from 454.029 ton in 2000 to 485.961 ton in 2011, while phosphorus load increased from 51.014 ton in 2000 to 58.437 ton in 2011. The nitrogen and phosphorus loads from aquatic agriculture took account of the largest percentage among the agricultural pollution sources. The agricultural land use and industrial structure changes caused nitrogen and phosphorus loads changed from 2000 to 2011 in the study basin. In the future, the corresponding control measures are recommended according to different pollution sources in order to reducing their pollution discharges. Moreover, recycling economy pattern is encouraged to achieve the resource utilization and reuse of planting, breeding and rural life waste.


PubMed | University of Catania, Chinese Institute for the Control of Agrochemicals, Beijing Academy of Agriculture and Forest Science and French National Institute for Agricultural Research
Type: Journal Article | Journal: Ecotoxicology (London, England) | Year: 2016

The seven-spot ladybird beetle, Coccinella septempunctata, is a major natural enemy of aphids in the field and in greenhouses in China and is part of integrated pest management (IPM). Imidacloprid, a highly efficient insecticide that not only kills aphids at lethal concentrations, but also can cause various sublethal effects in nontarget organisms. To strengthen IPM and its sustainability, it is important assessing possible side effects on natural enemies. When the effects of sublethal concentrations (LC5 and 10%LC5) of imidacloprid on C. septempunctata were evaluated, the adult longevity was shortened by 23.97 and 28.68%, and the fecundity reduced by 52.81 and 56.09% compared to control population. In the F

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