不同盐分土壤环境下绿肥腐解及养分释放动态研究

通过尼龙网袋埋田法研究了绿肥苕子、黑麦草在不同盐分滨海盐渍土壤中的腐解及养分释放规律。结果表明,不同盐分地块黑麦草干物质残留率、总有机碳含量和C/N总体高于苕子。苕子氮、钾在最初15天内快速释放,不同盐分地块的残留率分别为20.4%～34.0%和13.2%～18.1%,黑麦草钾在前45天释放了近90%,氮、磷释放持续整个腐解过程。低盐分地块绿肥钠的最终残留率为5.2%～7.6%,高盐分地块为36.2%～49.2%。不同盐分地块绿肥镁、钙、锌残留率以黑麦草高于苕子。铜的释放主要集中于前45天,之后趋于停滞。镁、铁、锰分别在腐解45～60天或45～75天出现养分富集现象。整体来看,禾本科绿肥干物质及养分残留率均高于豆科绿肥,高盐分明显阻滞了绿肥氮、钙、镁、铁、锰、铜和锌养分的释放。

Dynamics of Decomposition and Nutrient Release of Green Manure Under Different Saline Soils

A nylon net bag embedding method was carried out to study the decomposition and nutrient release of green manure Viciavillosa and ryegrass in coastal saline soil with different salinity. The results showed that the dry matter residue rate, total organic carbon content and C/N ratio of ryegrass in different salt plots were higher than those of V. villosa. The nitrogen and potassium of V. villosa were released rapidly in the first 15 days, and the residual rates in different salinity plots were 20.4%~34.0% and 13.2%~18.1% respectively. The potassium of ryegrass was released by nearly 90% in the initial 45 days, and the releasing of nitrogen and phosphorus continued in the whole decomposition process.The final residual rate of sodium in green manure in low salinity plots was 5.2%~7.6%, and in high salinity plots was 36.2%~49.2%.The residual rates of magnesium, calcium and zinc in ryegrass in different salinity plots were higher than those in V. villosa. The release of copper was mainly in the initial 45 days, and then tended to stagnate. The nutrient enrichment of magnesium, iron and manganese appeared in decomposed 45 to 60 or 45 to 75 days respectively. In general, the residue rate of dry matter and nutrient in gramineous green manure was higher than that of leguminous green manure. High salinity obviously blocked the release of nitrogen, calcium, magnesium, iron, manganese, copper, zinc and other nutrients in green manure.