艾比湖流域小尺度农田土壤养分的空间分布和盐渍化风险评价

Spatial heterogeneity of soil nutrients and salinization risk assessment of a small-scale farmland in Ebinur Basin in northwest China

为了解绿洲经济迅速发展背景下新疆典型尾闾绿洲-艾比湖流域小尺度农田土壤的养分和盐渍化状况,对该地区典型农田土壤中有机质、碱解氮、速效磷和速效钾等养分元素的空间分布、影响因素以及盐渍化风险状况进行了评价。结果表明:(1)农田土壤中有机质、碱解氮、速效磷和速效钾的含量均较高。所有土壤样点中总盐分含量属于高度变异,其他指标属于低度变异。(2)半方差函数分析表明土壤中碱解氮、速效磷和速效钾含量的空间变异性主要受施肥和灌溉等随机性因素的影响;而有机质和总盐分含量的空间变异性则受植被覆盖和土壤质地等结构性因素以及施肥、灌溉等随机性因素的共同影响。(3)空间分析表明,总体看农田土壤中有机质、碱解氮、速效磷和速效钾含量较高区域主要分布在中部和北部,受施肥、灌溉方式和植被盖度等因素的影响;而盐分含量较高区域主要分布在研究区南部和边缘区域,主要受地形、土壤质地和植被盖度的影响。(4)相关分析表明农田土壤中有机质、速效钾、速效磷、碱解氮和总盐分含量呈显著的负相关关系。盐渍化风险评估表明土壤中总盐分含量属于低度到中度的盐渍化风险,不会对主要作物棉花的生长产生危害,但应改进灌溉方式和种植制度,同时采用增施有机肥、进行秸秆还田等措施促进棉花作物的稳产、高产。

Our objective was to investigate the soil nutrient and salinization status of small-scale surface farmland within the Ebinur Basin, a typical rump lake basin in Xinjiang, which experienced recent economic success. We analyzed the spatial distribution and factors influencing soil nutrient composition, as well as conducted a soil salinization environmental risk assessment in the basin. The results indicated that ： （ 1 ） there were relatively high amounts of OM, AN, RP, and RK in the farmland surface soil. Among these five elements, the total salt content was highly variable, while the contents in the other four elements demonstrated low variation. （2） The semi-variance function analysis showed that the spatial distributions of AN, RP, and RK were mainly influenced by random factors, such as fertilization and irrigation, while the spatial distrihutions of OM and TS in the Ebinur Basin farmland were influenced by both random factors, such as fertilization and irrigation, and structural elements, such as vegetation coverage and soil texture. （3） The Spatial interpolation analysis revealed that, in general, the areas with high OM, AN, RP, and RK soil content were mainly distributed in the central and northern parts of the research area, and they were mainly influenced by the fertilization method, irrigation method, and the vegetation coverage; while the areas with high TS were mainly distributed in the southern and surrounding parts of the research area, and they were mainly influenced by the topography, soil texture, and the vegetation coverage. （4） The correlation analysis showed that soil OM, RK, RP, and AN have a negative correlation with the total salt content. The salinization risk assessment revealed that the whole area was within a low to moderate range of salinization risk, which will not influence the growth of the main crop, such as cotton, in the research area. However, in the future we should improve the irrigation and cropping system methods by increasing the application of organic manure and returning crop stalks to the field, thereby achieving a stable and high crop yield.