| With the sustainable development of the social economic, farmland resource decline sharply, land-use structure is unreasonable, the soil erosion is serious,ecological environment problem of the land stands out, thus the domestic and overseas governments and scholars focus on the soil quality evaluation as well as promoting the soil utilization potential. In the very moment that we violate the land utilization rules and ecological environment problem becomes increasingly highlighted. In this study,we set the Pengxi, Tianfu town as the study area, by means of the remote sensing data and GIS platform, combined with field investigation, we ensured the formation lithology, landform agrotype and element character of geochemistry of this area, and based on the synthetical analysis of the dynamic change information of the land use,we carried out the quality evaluating based on the soil geochemistry of the study area,take the evaluation result as the fundamental, we put the agricultural zoning into implementation. Through the research papers, we mainly obtained the following conclusion:(1)Tianfu town is typical hilly ground, the outdoor floor surface is Jurassic stratum and Quanternary stratum, under the control of the lithology, the surface configuration is a combinational type of the middle-hill, shallow-hill and Pingba. The soil type mainly include paddy soil, purple soil and yellow soil, thereinto the purple soil mainly distributes in the open zone of the Jurassic sandstone stratum, the paddy soil mother material is developed from the Quaternary alluvial stratum, the yellow soil mother material is developed from the old yellow alluvial.(2)In the 2002-2014 years, the area of arable land in the study area is decreasing, the grassland has a small amount of reduction, the forest land is reduced,the water area has no obvious change, but the construction land has obvious increasing trend. Although the quantity of cultivated land in the study area has been reduced, the land use pattern is mainly cultivated land, and other land is inserted in the land. Can also be seen that the absolute advantage of arable land, but also reflects the agricultural production is the main industrial activities in the study area.(3)Soil environmental health assessment results: the study area is the largest,accounting for 31.82%. Environmental health quality difference of 9.88% was mainly distributed in Changling village, Ma Dao Cun, Changping village, Tianfu village of environmental quality is good.(4)This paper use three geochemical factors—soil nutrition elements, soil heavy metal elements, good soil elements to synthetically evaluating the soil quality in Sichuan, Pengxi, Tianfu town, the result shows that the soil quality in Tianfu Town is superior, the geological and geomorphological condition as well as the geochemical condition of this area are all fit for the agroforestry development:(1)The main nutrient elements include N,P,K and organic material, the soil fertility overall quality of this area is superior, thereinto, the paddy soil is relatively better.(2)The soil heavy metal elements such as Cd,Hg,As,Cu,Pb,Ni,Cr in this area, by the method of the cumulative index analysis, the soil heavy metal pollution degree in this area is 0 class, the soil quality accord with the firs-rate demand of the National Soil Environmental Quality.(3)The micronutrient content such as Zn, Mo, B and Se in the soil reaches the normal state of nature, among which the soil with a higher concentration level of Se has a zonal distribution along the NE-SW direction along the tributary of the Fu river system,states in the high soil health quality land of the area, so it’s in favor of the production of the “high Se” agricultural products with good quality.(5)From the slope factor evaluation of the study area, the slope of the study area is divided into 5 grades, 4, 5 is the largest part of the study area, the terrain is gentle,suitable for agricultural cultivation. According to the evaluation results of the slope of the study area, it is known that the slope of the study area is divided into 4 grades, the3 and the 4 level of the slope to the vegetation is appropriate, through the study of the slope, it is beneficial to improve the quality and yield of agricultural products. By analyzing the topography and landform characteristics of the study area, it is known that the southwest and the East are more suitable for agricultural planting, which is conducive to the scale development of the agricultural industry. The Changling village,Shishan village, Long Ping Village, Lin village, Baihe Madao village is the most suitable for the development of the regional agricultural scale.In different types of landuse, the change of the content of each element also showed a different trend,concentrated distribution in the median stage of more, low value and high value stage of the less, the distribution of the extremely rare.(6)According to the characters of the geochemical elements, under the guidance of three principled framework-- “adjust measures to local conditions, high quality and efficiency, sustainabilituy”, based on the soil structure synthetical evaluation of the study area, we made a grading for the soil quality, and we made a division and an optimized layout of the agricultural region for the farmland of Tianfu town according to the geological unit and geomorphic units: we divided the study area into three units—Economic forest products base, Products of agricultural base, Non-pollution Agricultural production base, thereinto, the Economic forest products can be divided into the south rim economic forest and the north rim economic forest.(7)In this paper, we integrated the soil quality characteristic, and proposed the classification management of the agricultural land distribution area, and recommended some physical measures of ecological control and land balanced fertilization in the study area, thus provided scientific evidence for improving productivity of land and promote land utilization potential. |
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