新疆典型绿洲灌区土壤理化性状与盐分离子分布特征

Distribution Characteristics of Soil Physicochemical Properties and Salt Ions in Typical Oasis Irrigation Areas of Xinjiang

摘要:

土壤盐渍化和耕地质量下降严重制约新疆绿洲灌溉农业可持续发展，研究土壤理化性状与盐分离子分布特征是盐碱地改良与综合利用和绿洲灌溉农业高质量发展的前提和基础。以北疆玛纳斯河灌区、南疆阿克苏河灌区和喀什噶尔河灌区（阿克苏-喀什噶尔河灌区）为研究对象，定量分析了土壤（0~500cm）养分含量、含盐量及其离子组成分布特征。结果表明：玛纳斯河灌区和阿克苏-喀什噶尔河灌区土壤有机质、碱解氮、有效磷、速效钾、全氮含量均呈现随土层深度增加而逐渐降低的趋势。玛纳斯河灌区表层土壤（0~30cm）和0~100cm土层土壤有机质、碱解氮、速效钾、全氮含量和pH值平均值高于阿克苏-喀什噶尔河灌区，100~500cm土层土壤有机质、碱解氮、速效钾、全氮含量平均值低于阿克苏-喀什噶尔河灌区。阿克苏-喀什噶尔河灌区表层土壤（0~30cm）全盐量和电导率平均值比玛纳斯河灌区分别高21.14%和8.53%，60~100cm土层比玛纳斯河灌区分别低17.55%和16.50%。玛纳斯河灌区和阿克苏-喀什噶尔河灌区土壤阳离子均以Na+和Ca2+为主，阴离子均以SO2-4、Cl-为主，Na+和SO2-4分别为玛纳斯河灌区和阿克苏-喀什噶尔河灌区含量最高的盐基离子。玛纳斯河灌区表层土壤（0~30cm）53.85%属于盐渍土，30~60cm土层50.00%属于中度和重度盐渍土，60~100cm土层25.00%属于重度盐渍土，硫酸盐型盐渍土占主导地位，其次是氯化物-硫酸盐型盐渍土。阿克苏-喀什噶尔河灌区表层土壤（0~30cm）78.26%属于盐渍土，其中重度盐渍土占比最高，30~60cm土层60.86%属于轻度和重度盐渍土，60~100cm土层39.13%属于非盐渍土，氯化物-硫酸盐型盐渍土占比最高，其次是硫酸盐型盐渍土。研究结果可为新疆绿洲灌区盐碱地综合利用和作物精准施肥提供科学依据。

Abstract:

Soil salinization and arable land degradation have seriously restricted the sustainable development of oasis irrigation agriculture in Xinjiang. Exploring the distribution characteristics of soil physicochemical properties and salt ions is a prerequisite and foundation for saline-alkaline land improvement and comprehensive utilization as well as high-quality development of oasis agriculture. The distribution characteristics of nutrient contents, and salt content and its ions in the 0~500cm soil profile were quantitatively analyzed in the Manas River Irrigation Area in northern Xinjiang, and in the Aksu River Irrigation Area and Kashgar River Irrigation Area (Aksu-Kashgar River Irrigation Area) in southern Xinjiang. The results showed that the contents of soil organic matter, alkali-hydrolysable nitrogen, available phosphorus, available potassium, and total nitrogen in the study areas all showed a gradually decreasing trend with the increase of soil depth. In the Manas River Irrigation Area, the average values of soil organic matter, alkaline dissolved nitrogen, available phosphorus, total nitrogen content and pH value were higher in the 0~30cm and 0~100cm soil layers, but the average values of organic matter, alkaline dissolved nitrogen, available potassium and total nitrogen content in the 100~500cm soil layer were lower in the Manas River Irrigation Area. The average values of total salinity and electrical conductivity in the 0~30cm soil layer were 21.14% and 8.53% higher in the Aksu-Kashgar River Irrigation Area, but the average values of total salinity and electrical conductivity in the 60~100cm soil layer were 17.55% and 16.50% lower in the Aksu-Kashgar River Irrigation Area, respectively. In the study areas, the dominant cations were Na+ and Ca2+, while the dominant anions were SO2-4 and Cl-. In the Manas River Irrigation Area, Na+ was the highest salt ions, while SO2-4 was the highest in the Aksu-Kashgar River Irrigation Areas. In the Manas River Irrigation Area, 53.85% of the 0~30cm soil layer was classified as saline soil, 50.00% of the 30~60cm soil layer was classified as moderately and severely saline soils, and 25.00% of the 60~100cm soil layer was classified as severely saline soil. The dominant saline soil was sulfate, followed by chloride-sulfate. In the Aksu-Kashgar River Irrigation Area, 78.26% of the 0~30cm soil layer was classified as saline soil, with the highest proportion being severely saline soil. Additionally, 60.86% of the 30~60cm layer was classified as mildly or severely saline soils, and 39.13% of the 60~100cm soil layer was classified as non-saline soil. The dominant saline soils were chloride-sulfate, followed by sulfate. The results can provide a scientific foundation for the comprehensive utilization of saline-alkaline land and precise fertilization in the oasis irrigation area of Xinjiang.