The Multiscale Evaluation And Study Of The Cultivated Land’s Suitability In Hebei Province

The land resources, especially cultivated land resources，as the basis of the survival ofhuman life, its rational and efficient use has become one of the core issues of the society. Inorder to use the cultivated land reasonably, improve the food production capacity, andmeanwhile, do not cause a lot of environmental damage and soil and water loss, we make aresearch on the cultivated land suitability in Hebei Province with multi-scale method in thispaper, one based on the plot scale, and the other based on the county scale.In the plot scale, we use the method of evaluation index system to evaluate the cultivatedland suitable class in Hebei Province. The evaluation index includes effective thickness of soillayer, surface textural soils, soil profile, degree of salinity, soil organic matter content,and terrain slope index. What’s more, the soil relative humidity indicator is introduced. Wedetermined the grading and weight of each index through expert scoring method, and thendivided the cultivated land in Hebei Province into four categories, which includes the field offist level, the field of second level, the field of third level, and the field of fourth level. Amongthem, the field of fist level is mainly distributed in the central region of the Hebei Plain. Thefield of second level is mainly distributed in the eastern part of Hebei Plain. The field of thirdlevel is mainly distributed in the Bashang plateau and the Basin of Northwest HebeiMountains. The field of fourth level is mainly distributed in the Bashang plateau andNorthwestern Hebei Mountains.In the county scale, we evaluate the health status of the cultivated land productionfunction in Hebei province. During the process, we first establish the health status evaluationindex of the production function for cultivated land at the county level. Following this, wealso establish the discrimination model of the health thresholds. We defined the stabilitycoefficient of cultivated land productivity (Cs) as the health status evaluation index. Thediscrimination model of the health thresholds includes the correlation analyses between thestability coefficients of cultivated land productivity and the realistic productivity of cultivatedland, and the correlation analyses between the stability coefficients of cultivated landproductivity and net income per capita of cultivated land. Our results demonstrated that the stability coefficients of cultivated land productivity Cs=1could be used as the criticalthreshold of the health status evaluation of the cultivated land production function at thecounty level. The counties with lower stability coefficients of farmland productivity and poorhealth status of the farmland supply function were concentrated in the ecologically fragileareas of the northern Hebei province, where many people live in poverty. The counties withhigher stability coefficients and a healthy farmland supply function were located in the centraland southern Hebei province, where the land use was rational and most people were wealthy.This suggests that people’s poverty status is spatially related to the health status of thefarmland supply function.The cultivated land suitability degree is related not only to the natural condition ofcultivated land, but also to the social and economic factors of cultivated land. The cultivatedland suitability evaluation in the plot scale mainly focus on the evaluation of the productionconditions, while there are defects of the social and economic index selection, which cannotreflect the suitability degree of cultivated land intergratedly. And the health status evaluationof the cultivated land production function at county level, mainly focus on the evaluation ofthe production capacity. In the process of evaluation, we have to consider the social andeconomic factors in addition to the natural conditions’ effects on the cultivated land, whichintegratedly reflects the general situation of the cultivated land quality, and solves the problemthat the plot scale cannot solve. Under the constraints of the county level, it is more conduciveto the improvement of the regional economic environment and sustainable economicdevelopment.In this paper, we combine the cultivated land suitability evaluation and the health statusevaluation of the cultivated land production function through the method of upscaling anddownscaling. The correlation analyses were carried out between the cultivated land suitabilityevaluation at county level and the stability coefficients of cultivated land productivity atcounty level, and then obtain the health threshold to the cultivated land suitability evaluationat county level. Under the constraints of the health threshold of the cultivated land suitabilityevaluation at county level., we re-evaluate the cultivated land suitability evaluation in the plotscale in Hebei Province. The adjusted cultivated land suitability evaluation in the plot scale will provide scientific and theoretical basis for the cultivated land use, and then it will beconducive to the improvement of the regional ecological environment and sustainableeconomic development.In order to study the suitability of the cultivated land status further, we evaluate thecultivated land suitability subtype on the basis of the adjusted cultivated land suitabilityevaluation. According to the differences and the weights of the evaluation index, we dividedcultivated land suitability subtype into seven subtypes. They are soil water deficit subtype,soil erosion subtype, limiting gradient subtype, soil salinization subtype, complex soil profilesubtype, gritty soil subtype, organic matter deficit subtype. In this paper, we evaluate thesubtypes for the field of second level, the field of third level and the field of fourth level. Theevaluation results show that the field of second level is mainly affected by soil relativehumidity and soil organic matter content. Adjust irrigation techniques, and measures toincrease the relative water content and soil organic matter content of soil are the main ways toincrease production for the field of second level. The field of third level is mainly affected byeffective thickness of soil layer and soil relative humidity. The measures of effectivelyreducing soil and water loss, increasing the proportion of cultivated land irrigation areeffective ways for the sustainable development of the field of third level in Hebei Province.The field of fourth level is mainly affected by soil relative humidity and effective thickness ofsoil layer. The measures of reducing soil erosion and conversion of cropland to forest andgrassland are effective ways for the sustainable development of the field of fourth level inHebei Province.In summary, the cultivated land suitability evaluation on multi-scale in Hebei provinceprovides important referents for the adjustment of land-use structure, and for theestablishment of the policy of eliminating regional poverty in Hebei province, especially inthe northern Hebei Province.