三江平原不同土地利用方式下土壤硫含量变化特征

Changes in Soil Sulfur Under Different Land Use in Sanjiang Plain.

通过分析三江平原不同土地利用方式下土壤总硫、有效硫含量的变化,探明土壤硫含量演变特征。结果表明,小叶章湿地土壤总硫和有效硫含量高于开垦后的农田土壤,开垦导致土壤硫含量下降,且随着耕种年限的增加,土壤总硫和有效硫含量呈逐年下降趋势。弃耕7 a后土壤总硫和有效硫含量有所增加,但增加量相对较小,表明土壤硫库耗竭易、恢复难。土壤硫与有机质含量之间呈显著正相关关系,提示湿地开垦后土壤有机质含量降低可能是引起土壤硫肥力下降的主要因素,提高土壤有机质含量将有利于维持和提高农田土壤硫肥力。

Changes in total sulfur and available sulfur in soils under different land use in the Sanjiang Plain were analyzed to explore characters of the evolution of sulfur content in the soils. Results show that Calamagrostis angustifolia wetland is higher than cropland in content of total sulfur and available sulfur, which indicates cultivation depletes soil S, and soil total sulfur and available sulfur show a decreasing trend with each passing year. After desertion under ＂Grain for Green＂ Project for 7 years the contents of total sulfur and available sulfur in the soil increased, but the increase is very limited, which indicates that the soil S pool, once depleted, is hard to restore. Soil sulfur is found to be positively related to soil organic matter, suggesting that decreased soil organic matter due to cultivation might be the main cause of the decrease in S fertility of the soil. So that, increasing soil organic matter is propitious to the maintenance and increase of soil S fertility.