Search

For revealing the spatial distribution characteristics and laws of land use on topographic gradient under different geomorphic forms in poor mountainous areas, the paper took Bijie City as the research area, which was divided into karst and non-karst areas. Based on land use data and DEM in 2009 and 2018, different characteristics of the land use change under different terrain gradients was discussed through the methods of topographic index, topographic distribution index. The results are as follows. 1) The land use types in karst and non-karst areas are hierarchical in terrain gradient. Dry land, paddy field, garden land, construction land, road and water area have certain selectivity for low terrain, while woodland, shrub land, grassland and unused land have certain selectivity for high terrain, among which land use types in non-karst areas are more widely distributed in low terrain area. 2) It has obvious effect for the terrain gradient on land use diversity in karst and non-karst areas. It had great changes as the augment of terrain gradient in 2009. And in 2018, the lower the terrain gradient was, the higher the diversity was. Compared with non-karst area, the diversity of karst area is higher in interval 1, 2 and 5 than that of non-karst area, but the opposite is true in interval 3-4. 3) The terrain gradient effect of karst and non-karst land use degree is significant, which shows the higher the terrain gradient is, the lower the land use degree is. The spatial difference is influenced by natural environment, socio-economy and policy. [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]

[Objective] The objective of the paper is to provide the scientific basis for rational fertilization in Jianhe County of Guizhou Province and similar areas. [Method] The effects of soil nutrient indexes(total N .organic matter, available N .available K, available P, total P and total K)on soil fertility are explored by using variation coefficient method, correlation coefficient method and weighted mean method, and then the soil fertility in paddy field and dry' land is evaluated by using improved Nemerow comprehensive evaluation method combined with the weight coefficient mean value of the three methods. [Result] The soil available k in paddy field and total P in dry land were at a lower level, while other nutrient indexes were at a medium-high, high and higher level. The soil available N content in six dry' land sampling sites with different plants was high. Soil total P and available k fluctuate greatly among sampling sites, while organic matter content fluctuates less. The soil available P in fertility factor weighted coefficient of paddy field and dry land was the highest, respectively 0. 2710 and 0. 2358 comparing the mean value of the three weighted method weighted coefficient. The available P is the main factor influencing soil fertility in paddy field and dry' land and soil fertility indexes is 1.52 and 1.63 separately. The soil comprehensive fertility was at a fertile level. [Conclusion] The soil fertility of paddy field and dry land in Jianhe County is at a fertile level, and available P is the main factor influencing soil fertility in paddy field and dry land. The soil N content in paddy field and dry land is high, which can meet the demand of crop production. Therefore, N fertilization should be reduced in production. The soil K content in paddy field is low, and the corresponding fertilization measures should be taken to improve K supply level in paddy field. [ABSTRACT FROM AUTHOR]