Search

In order to scientifically and effectively protect and improve the quality of cultivated land, and accurately understand the quantity of cultivated land quality grades and the distribution of spatial characteristics, in this paper, analytic hierarchy process(AHP), Delphi, fuzzy mathematics, and summation method were used based on the Geographic Information System(GIS) to establish a comprehensive evaluation system for 30 counties(districts) in the piedmont plain of Taihangshan Mountain in Hebei province and evaluation of grade was conducted. The results showed that the highest grade of cultivated land in the study area was 1, the lowest grade was 8, the average grade was 3.24, and the overall quality was high. Based on the natural breakpoint method, grades from 1-3 were excellent, mainly distributing in the piedmont plain of Shijiazhuang and some areas of Handan. Grades from 4-6 were medium, mainly distributing in the north of the piedmont plain of Baoding and some areas of Xingtai. Grades 7-8 were low, mainly distributing in the south of the piedmont plain of Baoding and some areas of Xingtai. The quality of cultivated land in the central and southern regions of the study area was higher than that in the central north and western regions. The study area had the highest proportion of excellent places at 64.49%, and the lowest proportion of low grades at 4.03%. In order to ensure the sustainable use of cultivated land of excellent grades without obvious obstacles in the study area, the maintenance of site conditions should be emphasized, and deep subsoiling and deep turning, and the maintenance of irrigation facilities should be carried out in a timely manner. In the land with medium grades, the steady progress of soil and water conservation work should be continued to increase thickness of arable layer. In low grade places, soil physicochemical properties should be rapidly improved by returning straw to the field, planting green manure or increasing the application of organic fertilizer and biochar. [ABSTRACT FROM AUTHOR]

【Objective】 Research on remote sensing evaluation of cultivated land quality is of great significance to realize real-time and effective management and protection of cultivated land quality, promote the development of modern and efficient agriculture and ensure national food security.【Method】 The present paper took Conghua area as the study area, the spectral parameters were calculated and obtained from GF-1 image data by using various transformation technologies. And the correlation coefficient and variance inflation factor were used to select the spectral response of the cultivated land quality indicators. The remote sensing spectral response models of cultivated land quality in Conghua district were constructed based on linear（ PLSR） and nonlinear （BPNN, GA-BPNN） models, and the optimal model was used to realize the rapid inversion and spatial mapping of cultivated land quality.【Result】 The crop spectral response indexes of cultivated land quality were FD-3, SD-4, EVI and LR-4, and the correlation coefficients with cultivated land quality were 0.661, 0.663, 0.714 and-0.674, respectively, indicating that red and near infrared in GF-1 image were the crop spectral response bands of cultivated land quality. The PLSR, BPNN and GA-BPNN models were used to retrieve the cultivated land quality respectively. Compared with the inversion accuracy, it was found that the GA-BPNN model could quickly realize the inversion of cultivated land quality（R~2=0.64,NRMSE=10.75%）. Spatial mapping and validation of cultivated land quality using optimal model were conducted, and the results showed that the crop spectral indicators extracted from GF-1 satellite image data based on GA-BPNN model could quickly and accurately retrieve the cultivated land quality at regional scale. 【Conclusion】 The use of remote sensing technology is helpful to quickly understand the quality of cultivated land at the regional scale, improve the existing discipline system of cultivated land quality evaluation, promote the development of the discipline, and provide a theoretical basis for the subsequent spectral inversion of cultivated land quality. [ABSTRACT FROM AUTHOR]

Optimizing the layout of monitoring sample points according to the spatial distribution characteristics of cultivated land quality can improve the monitoring efficiency and accuracy of cultivated land quality. In this paper, the environmental factors that change synergistically with cultivated land quality were selected as auxiliary variables, the spatial variation characteristics of cultivated land quality were analyzed by geostatistics, and the layout scheme of cultivated land quality monitoring sample points was optimized by Cokriging method. The results showed that the interpolation accuracy of 66 monitoring points obtained by Cokriging under the optimal（5 km×5 km）grid interval was better than that of ordinary Kriging under the small（2 km×2 km）grid interval; Under the same grid layout, the interpolation accuracy of monitoring points obtained by Cokriging method was better than that of ordinary Kriging. This shows that the Cokriging method combined with easily obtained auxiliary variable information can optimize the layout of cultivated land quality monitoring points, obtain the sample point scheme with fewer monitoring points, reduce the cost and improve the accuracy of cultivated land quality monitoring. [ABSTRACT FROM AUTHOR]

Cultivated land is the oldest and most extensive human-land system formed by human civilization through the transformation of the earth′s surface for thousands of years. The ability of cultivated land system to maintain stable production and healthy environment is reflected in the quality characteristics of cultivated land, under certain technical and economic conditions within a certain period of time, and the development and utilization value is expressed as the resource attribute of cultivated land. This paper clarifies the cultivated land system, the quality of cultivated land and cultivated land resources, on the basis of cognitive connotation and evolution process. The "nature - humanity" constituent elements and their coupling relationship of cultivated land resources are analyzed, characteristics and formation mechanism of "horizontal-vertical" structure, "production-ecology-living" function synergy and transformation relationship. The exchange process and response mechanism of "matter-energy-information", and the service value and evolution law of "economy-ecologysociety", the cognitive system of cultivated land resources is constructed, which is "two-dimensional factor-triple function-multiple value". A new way of systematically recognizing cultivated land resources is proposed, deconstructing the internal mechanism and external value of cultivated land resources, service farmland protection and quality improvement and natural resource assets "two unified" management, to support the construction of a new pattern of resource utilization and cultivated land protection under high-quality crossdomain development. [ABSTRACT FROM AUTHOR]

[Objective] In order to comprehensively maintain and improve the production, ecological and living functions of the farmland ecosystem, under the different types of cultivated land, the present paper analyzed the spatial and temporal evolution trajectory and characteristic differences of the quantity and quality of the water and dry land in the cultivated land based on the perspective of the ’trinity’ protection for quantitative and quality ecological development.[Method] Taking the Jiangjin District of the Three Gorges Reservoir as an example, the land use status and cultivated land quality grade evaluation result data, the standard deviation ellipse, landscape pattern index, nearest neighbor index method, etc. were used to study the quantity, the spatial and temporal evolution pattern of quality and ecology. [Result]（i） Quantity, the distribution of flooded and dry land in Jiangjin District had a trend of further expanding to the hinterland of Jiangjin District. The evolution path of dry land changes from northwest to southeast, and the evolution path of paddy field changed from southwest to southeast;（ii） Quality, the overall quality of the paddy field was higher than that of the dry land. The grade of the paddy and dry land was gradually decreasing from the central and western regions to the north and south.（iii） Ecological, the shape of the paddy and dry land was complex and fragmented, with reduced connectivity and significant aggregation.[Conclusion] The implementation of arable land zoning and types of protection measures, to achieve the development momentum of characteristic agriculture according to local conditions, provides reference for the protection of arable land resources in this area, the formulation of ’tri-in-one’ protection policies and the optimization of the layout of arable land. [ABSTRACT FROM AUTHOR]