Abstract: Sulfur,calcium,and magnesium are essential elements in plant and play very important functions in physiology and plant nutrition.Based on the long-time stationary experiment,the changes of soil sulfur,calcium and magnesium were studied under a condition of 22-year alfalfa succession in Loess Plateau.The results show that the contents of total sulfur,available sulfur,water soluble sulfur,adsorbent sulfur,HCl soluble sulfur,total inorganic sulfur,and organ sulfur in tilth soils,after long-time P-fertilizer application,increased by 9.41%,62.41%,47.51%,30.07%,2.25%,5.38%,and 17.54%,respectively.The contents of total sulfur,available sulfur,water soluble sulfur,adsorbed sulfur,HCl soluble sulfur,total inorganic sulfur,and organic sulfur in tilth soils,after long-time NPM-fertilizer application,increased by 20.89%,98.31%,68.44%,57.34%,8.07%,12.54%,and 37.69%,respectively.The contents of total calcium,available calcium,water soluble calcium,exchangeable calcium,and HCl soluble calcium in tilth soils,after long-time P-fertilizer application,increased by 4.64%,4.27%,11.66%,4.05%,and 8.59%,respectively,but the content of residual calcium decreased by 2.21%.The contents of total calcium,available calcium,water soluble calcium,exchangeable calcium,and HCl soluble calcium in tilth soils,after long-time NPM-fertilizer application,increased by 8.69%,8.30%,51.59%,6.73%,and 27.77%,respectively,but the content of residual calcium decreased by 26.23%.The contents of total magnesium,available magnesium,water soluble magnesium,exchangeable magnesium,HCl soluble magnesium,and residual magnesium in tilth soils,after long-time NPM-fertilizer application,increased by 7.38%,61.98%,63.16%,61.85%,5.81%,and 8.97%,respectively.Two peaks of available sulfur in soil profiles were detected with a transportation trend of available sulfur to deep soil layers.Additionally,the eluviation and accumulation of available calcium and magnesium occurred in soil profiles.

Key words: Loess Plateau, Alfalfa succession, Sulfur,calcium,and magnesium, Long-term experiment

摘要： 以22年定位试验为基础,研究黄土高原长期种植紫花苜蓿(Medicago sativa L.)情况下土壤硫、钙、镁组分的变化。结果表明:长期施P使苜蓿连作耕层土壤总硫、有效硫、水溶性硫、吸附性硫、HCl可溶性硫、总无机硫和有机硫含量分别增加9.41%、62.41%、47.51%、30.07%、2.25%、5.38%和17.54%;长期施NPM使苜蓿连作耕层土壤总硫、有效硫、水溶性硫、吸附性硫、HCl可溶性硫、总无机硫和有机硫含量分别增加20.89%、98.31%、68.44%、57.34%、8.07%、12.54%和37.69%。长期施P使苜蓿连作耕层土壤全钙、有效钙、水溶态钙、交换态钙和酸溶态钙含量增加分别增加4.64%、4.27%、11.66%、4.05%和8.59%,但残余态钙含量降低2.21%;长期施NPM使苜蓿连作耕层土壤全钙、有效钙、水溶态钙、交换态钙和酸溶态钙含量增加分别增加8.69%、8.30%、51.59%、6.73%和27.77%,但残余态钙含量降低26.23%。长期施NPM使苜蓿连作耕层土壤全镁、有效镁、水溶态镁、交换态镁、酸溶态镁和残余态镁含量分别增加7.38%、61.98%、63.16%、61.85%、5.81%和8.97%。此外,有效硫在土壤剖面上出现双累积峰,有向深层土壤迁移的特征;有效钙、有效镁在土壤剖面上存在淋溶累积现象。此研究结果可为苜蓿种植和管理提供依据。

关键词: 黄土高原, 苜蓿连作, 硫、钙、镁, 长期试验