干旱区精河流域绿洲化过程中土壤养分时空变异研究

目的]对干旱荒漠区不同土地利用方式下土壤养分时空特征进行研究,为绿洲土壤的科学施肥及更合理的土地资源开发利用提供理论依据,以促使土壤养分在精河流域平原绿洲系统中合理迁移和分布。方法]以精河流域平原绿洲为靶区,基于GIS与地统计学方法,利用2003年和2018年不同土地利用方式下获取的土壤采样数据,对绿洲化过程中土壤养分(有机质、碱解氮、速效磷)的时空动态变化及重心迁移特征进行分析。结果](1)2018年的土壤有机质、速效磷低于2003年,而碱解氮高于2003年。在空间上,各养分含量的高值区均出现在绿洲北部和西北部,低值区则主要位于绿洲边缘及南部区域;(2)对土壤养分综合分级评价结果显示,2003—2018年绿洲化过程中研究区土壤养分整体下降,中等及偏上水平的土壤养分重心沿精河向绿洲东北方向(艾比湖西南缘)及西北部的博乐绿洲方向迁移;(3)不同土地利用方式下,土壤养分含量均与土壤pH呈显著或极显著负相关关系,其中在草地、耕地和未利用地中呈极显著的差异(P<0.01),在林地中两者呈显著差异(P<0.05)。结论]该研究对精河流域绿洲化过程中土壤养分变化和迁移特征进行的时空对比分析,有助于推进研究区平原绿洲耕地的利用和发展布局,为实现生态可持续发展提供重要参考。

SPATIOTEMPORAL VARIATION OF SOIL NUTRUENTS IN THE PROCESS OF THE JINGHE RIVER BASIN IN ARID REGION

The spatiotemporal characteristics of soil nutrients under different land use modes in arid and desert areas are studied to provide theoretical basis for scientific fertilization of oasis soil and more rational development and utilization of land resources, so as to promote the rational migration and distribution of soil nutrients in the plain oasis system of Jinghe river basin.Taking the plain oasis in the Jinghe river basin as the target area, and based on the GIS and geostatistical methods, the spatial and temporal dynamic changes and center of gravity transfer characteristics of soil nutrients (Organic matter, Alkali hydrolyzed Nitrogen and Rapidly available phosphorus) in the process of oasification were analyzed by using the soil sampling data obtained under different land use modes in 2003 and 2018.The results showed that:(1) In the process of oasification, soil nutrients decreased with the increase of oasis area in the Jinghe river basin, and the nutrient elements were distributed in sheets within the oasis.In 2018, soil organic matter and available phosphorus were lower than that in 2003, while available nitrogen was higher than that in 2003.In terms of spatial distribution, the high value regions of nutrient contents were located in the north and northwest of the oasis, while the low value regions were mainly located in the edge of the oasis and the southern region.(2)The results of comprehensive grading evaluation of soil nutrients showed that the soil nutrients in the study area decreased as a whole during the process of oasification from 2003 to 2018, and the center of gravity of soil nutrients at medium and upper levels migrated along the Jinghe river to the northeast(Southwest margin of AiBi lake) and northwest of the Bole oasis.(3)Under different land use modes, soil nutrient content was significantly or extremely significantly negatively correlated with soil pH, especially in grassland, cultivated land and unused land (p<0.01) and in forest land (p< 0.05).In summary, the spatiotemporal comparison and analysis of soil nutrient changes and migration characteristics in the process of oasification in the Jinghe river basin will promote the utilization and development layout of cultivated land in the plain oasis in the study area, and provide important reference for the realization of ecological sustainable development.