关键词: 耕地, 土壤养分, 空间分异, 地统计学, 叶城县

Abstract:  Yecheng county is a fully irrigated agricultural area in the northwest arid region of Xinjiang. The spatial differentiation characteristics of main nutrients in cultivated soil were studied to provide a theoretical basis and practical reference for implementing the strategy of “storing grain in the land”,  cultivating soil to improve grain yield,  and developing regional precision agriculture. Taking Yecheng County of Xinjiang as the research area,  four main nutrients,  including organic matter,  alkalihydrolyzable nitrogen,  available phosphorus,  and available potassium,  were selected. Based on GIS,  the optimal semi variance function model was fitted to analyze their spatial differentiation characteristics by combining classical statistics with geostatistics. The comprehensive quality evaluation was carried out by the Nemerow index method. The results are as follows. The contents of organic matter,  alkalihydrolyzable nitrogen,  available phosphorus,  and available potassium were 11.68 g/kg,  52.19 mg/kg,  6.59 mg/kg,  and 131.51 mg/kg,  respectively. Compared with the second soil survey,  the contents of the other three nutrients were increased in varying degrees except for available potassium. The variation coefficient of each nutrient ranges from 22.07% to 68.19%,  which belongs to medium variation degree,  and available phosphorus > alkalihydrolyzable nitrogen > available potassium > organic matter.  The ratio of available phosphorus to available potassium was 0.08 and 0.06,  which was dominated by structural factors. The ratio of organic matter to alkalihydrolyzable nitrogen was 0.71 and 0.61,  which was dominated by random factors.  The comprehensive quality index of main nutrients in cultivated soil was 1.73,  which was 0.4 higher than that in 1982.  The pattern of “lack of nitrogen,  less organic matter,  less phosphorus,  and more potassium” is present. The organic matter decreases from the middle mountain area to the northeast. Alkalihydrolyzable nitrogen increased gradually from southwest to northeast. The highvalue area of available phosphorus showed patchy dispersion and embedment. There is no strong regularity in the direction of available potassium. According to the characteristics of soil parent material in Yecheng County,  it is suggested to pay attention to the small amount of multiple fertilization,  increase the organic fertilizer,  phosphorus fertilizer,  and nitrogen fertilizer as a whole,  and adjust the regional fertilization structure according to the spatial differentiation of nutrient content. It is possible to appropriately increase the input of potassium fertilizer in boxikere,  and strengthen the construction and maintenance of the forest protection system in yilikqi township.

Key words: cultivated land, soil nutrients, spatial differentiation, geostatistics, Yecheng County