施硅对稻田土壤氮矿化的影响(英文)

Nitrogen mineralization in two paddy soils as affected by silica source addition

供试土壤分别采自日本山形县农业试验场 (土壤A)和鹤冈市吉田农户的水稻田 (土壤B)。将两种水稻土分别与硅酸钙和硅酸混合 ,在密闭条件下恒温培养 4周 ,测定施硅对土壤氮矿化的影响。在培养土壤中加入15N标记硫酸铵以评价施硅对加入土壤中氮去向的影响。结果表明 :在培养 1周内 ,施用硅酸钙 1g·kg- 1,2g·kg- 1与不施硅相比 ,土壤pH增加 0 .2～ 0 .3,NH4 + N总积累量分别增加 2 0 % ,2 6% (土壤A)和 9% ,11% (土壤B) ,土壤氮净矿化速率分别增加 2 6% ,35%(土壤A)和 13% ,13% (土壤B)。处理间差异在培养开始后的第 1周大于第 4周。硅酸对土壤pH及氮矿化速率没有影响。两种硅肥对施入土壤中氮的去向均无明显影响。研究结果揭示 ,硅酸钙促进土壤氮矿化的原因不是硅元素本身 。

The beneficial effect of Si on rice growth had been confirmed by many documents.However,the information on the relationship between Si fertilizer application and the availability of soil N was little.Two paddy soils were mixed with different sources of Si fertilizer (calcium silicate and silicic acid), and incubated under completely closed condition. 15 N labeled ammonium sulfate was added to evaluate the fate of N applied with respect to Si application.From 0 to 1 week after incubation,calcium silicate application increased the soil pH by 0.2-0.3 unit as compared to no Si application.Total accumulation of NH 4 + N was increased by 20%,26% in soil A and 9%,11% in soil B,and the net rate of N mineralization was increased by 26%, 35% in soil A and 13%,13% in soil B by addition of calcium silicate at the rates of 1 and 2 g kg -1 ,respectively.The difference in soil pH and N mineralization among treatments was more significant at the first week than at the 4th week after incubation.Silicic acid had no effect on soil pH,ammonium accumulation and the rate of N mineralization.Data suggested that calcium silicate fertilizer accelerate the N mineralization not by Si element but through its effect on soil pH.