氰氨态氮的硝化抑制效应及其在农田的应用

本文探讨了氰氨态氮的硝化抑制效应,比较了氰胺和双氰胺在农田的使用效果。研究结果表明,氰胺和双氰胺都能抑制硝化作用,从而提高氮肥利用率。在水田土壤中,氰胺的分解速度比双氰胺缓慢,硝化抑制效应持续时间较长,其增效作用比双氰胺大;在旱田土壤则相反,双氰胺的硝化抑制效应大于氰胺。在正常的条件下,氰胺是氰氨化钙分解的主要产物。试验结果表明,氮肥与氰氨态氮的配合比例以5:1～3:1为宜。在多数情况下,这个浓度水平对作物无害,并能充分发挥增效作用。同时,在水田土壤中,氮肥与氰氯化钙配施,其增效作用比双氰胺大,而成本却比双氰胺为低。

EFFECTS OF CYANAMIDE NITROGEN ON THE INHIBITION OF NITRIFICATION AND ITS FIELD APPLICATION

Incubation, pot and field experiments were carried out to study the inhibitory effects of nitrification of cyanamide nitrogen in cultivated soils, and the response of the inhibitors on yield by growing field crops. The results are summarized as follows: 1. The effect of cyanamide and dicyandiamide on the inhibition of nitrification is significant. It was observed that in the inhibitory effect of cyanamide on the inhibition of nitrification was higher than that of dicyandinamide on the waterlogged state; the lower value in the latter could be attributed to the higher rate of decomposition in comparing with the former. Inversely, the inhibitory effect of dicyandiamide was higher than cyanamide on the upland state. 2. Experimental results showed that suitable ratio of nitrogen applications from 5:1 to 3:1 by mixing nitrogen fertilizer with cyanamide nitrogen, i.e. calcium cyanamide application rate by 17-25% of the total fertilizer nitrogen should be applied under most of the soil conditions. That doses and ratios can increase the yie Ids, without any harmful effect on crops. 3. When nitrogen fertilizer was applied in combination with calcium cyanamide, more fertilizer nitrogen were absorbed by crops than that with dicyandiamide under waterlogged conditions, therefore it can reduce the production cost.