| Cultivated land is the basic production factor for human survival and the most basic resource guarantee for food security.The development of cultivated land quality connotation is the result of comprehensive influence of natural,social,economic and technological progress.Under the background of the new era,we should pay more attention to the"trinity"of the quantity,quality and ecology of cultivated land.It is of great significance to evaluate the quality of cultivated land for ensuring the quantity of cultivated land,improving the quality of cultivated land and coordinating and sustainable development of cultivated land and ecological environment.Therefore,on the basis of fully understanding the evaluation system of cultivated land quality,the evaluation index is integrated and optimized,and a set of scientific and reasonable evaluation methods is established to realize the scientific accuracy of the evaluation results of cultivated land quality.In this study,the connotation of cultivated land quality was deeply studied,and the cultivated land quality was evaluated from two dimensions:basic soil fertility and ecological health.Among them,basic soil fertility represents the natural quality of cultivated land,and is a comprehensive reflection of the inherent and basic quality of cultivated land,including three indicators:geographic characteristics,soil properties and construction level;and ecological health is the quality of cultivated land.The comprehensive evaluation index can be divided into two indexes:soil health and biological characteristics.Taking Laiyuan County of Hebei Province as the research area,a more systematic and more regional characteristics of cultivated land quality evaluation index system is proposed.Through the calculation of obstacle degree,the factors of cultivated land quality obstacles in Laiyuan County are diagnosed and identified,and the types of cultivated land quality obstacles are divided.The specific results and conclusions are as follows:(1)On the basis of defining the connotation of cultivated land quality,the index system and evaluation method of cultivated land quality evaluation are determined by consulting relevant literature.According to the principle of index system construction and the applicability of index to the study area,combined with the field investigation,the influence degree of the proposed index on the actual study area is analyzed,and the indices without difference are excluded.Relying on SPSS software to analyze the correlation of screening indicators,using correlation coefficient to measure the degree of mutual influence among the indicators,excluding the indicators with high repeatability one by one,and taking the factors that have significant influence on cultivated land quality difference as the indicators of cultivated land quality evaluation in Laiyuan County,the evaluation index system of cultivated land quality in Laiyuan County is finally determined,and classified according to the connotation of the indicators.Medium-basic soil fertility includes three first-level indicators of geo-characteristics,soil properties and construction level,and 15 second-level indicators of field slope,soil nutrient elements and irrigation guarantee rate.Ecological health includes two first-level indicators of soil health and biological characteristics,and three second-level indicators of pesticide residues in soil and earthworms in soil.By using analytic hierarchy process to determine the index weight of the evaluation index system of cultivated land quality,combining the weighted summation method with the continuous product method,the basic soil fertility of cultivated land quality is weighted summation.At the same time,the ecological health coefficient is amended step by step,and the cultivated land quality index of Laiyuan County is calculated.The results show that the cultivated land quality index of Laiyuan County is between 20.70 and 71.91.According to the final evaluation scoring range and the natural breakpoint method,the cultivated land quality in Laiyuan County is divided into six categories.(2)The results of cultivated land quality evaluation in Laiyuan County were analyzed by ArcGIS 10.2 software.The cultivated land area of Laiyuan County showed a"pyramid"distribution trend basically.Among them,the area in the[30,40]section was relatively large.The cultivated land area in this section totaled 15089.1923 hm~2,accounting for49.68%,accounting for about half of the total cultivated land area of the county.According to the spatial distribution characteristics,the quality of different cultivated land in Laiyuan County is staggered,showing a high spatial distribution pattern in the central part and a low spatial distribution pattern in the north and South part.The relatively high cultivated land quality index is concentrated in Laiyuan Town,Baishishan Town and Beishifo Town.In order to explore the impact of ecological health on cultivated land quality,the basic soil fertility index and cultivated land quality index of Laiyuan County were compared and analyzed,and the scoring range of basic soil fertility index was 62.5-88.According to the function of natural breakpoint,it was divided into three levels.The scoring range of cultivated land quality index was 20.70-71.91,and the natural breakpoint with the same distance was divided into six levels.The result shows that the quality of cultivated land revised by ecological health factor has decreased after 1 1046.5282 hm~2,which is more than one third of the total area of cultivated land in the county.The towns affected by ecological health factors include Laiyuan Town,Yinfang Town,Beishifo Town,and other nine towns,reflecting their health.Ecological health factors have a great impact on the evaluation of cultivated land quality in Laiyuan County,but also show that the ecological health of cultivated land in Laiyuan County is not good.Overall,the overall quality of cultivated land in Laiyuan County is low,and the potential for improvement is great.(3)Based on the evaluation of cultivated land quality,the obstacle factors affecting the basic land productivity in Laiyuan County were diagnosed and identified.The effect of15 basic land productivity indicators on the improvement of cultivated land quality was quantified by the concept of barrier degree,including slope,altitude,effective soil thickness,and the effective ways to improve the basic land productivity and carry out land consolidation projects were explored.The results showed that the barrier degree was an effective way to improve the basic land productivity and carry out land consolidation projects in Laiyuan County.The two most important obstacle factors affecting the county's basic soil productivity are the effective soil layer thickness and irrigation guarantee degree.According to the order of obstacle factors in each evaluation unit,the main obstacle factors which have the greatest impact on the evaluation unit are screened out.The results show that five obstacle factors,namely,irrigation guarantee degree,altitude,soil configuration,effective soil layer thickness and barrier layer distance from the surface depth,are the main obstacle factors of the basic land force in Laiyuan County,and the obstacle is carried out according to this result.In summary,through the construction of evaluation index system,the quality of cultivated land in Laiyuan County is evaluated and calculated.,the influence of ecological health factor on the quality of cultivated land was found out,and the obstacle degree is introduced to diagnose and identify the obstacle factors of cultivated land quality and divide the obstacle type areas.It is of practical significance to the protection of cultivated land in the county. |
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