应用^(15)N示踪技术研究氮磷复(混)合肥料的肥效和残效

STUDY ON THE FERTILIZER EFFICIENCY AND RESIDUAL EFFECT OF N,P COMPOUND AND N.P MIXED FERTILIZERS BY ^(15)N TRACER

1984～1986年连续4茬作物的盆栽试验结果表明:①硝酸磷肥、尿素磷铵和尿素普钙对春麦和麦茬稻均有明显的增产作用。但肥料之间无显著差异。②春麦对不同肥料氮的利用率无明显差异,而对肥料中不同形态氮素的利用率略有差异。麦茬稻对尿素普钙中氮的利用高于硝酸磷肥;而不同形态氮素的利用率之间差异较小。③收获春麦后土壤中尿素磷铵和尿素普钙中氮的残留率分别为52.9%和52.1%,高于硝酸磷肥(49.4%)。不同形态氮麦中尿素残留最多;NO_3^--N 次之;磷铵氮最少。在收获麦茬稻后,土壤中仍有1%的残留氮素。④春麦生长期中,氮肥的损失率为12.0%～24.5%。麦茬稻生长期间,氮肥的损失率约为20.0%～30.0%。显然过多的施肥是不经济的。特别是硝酸磷肥和尿素。⑤第四茬水稻对残留肥料仍可利用,其利用率达0.8%～1.1%。

Pot experiment was conducted from 1984 to 1986,with four conse- cutive cultivated crops.The results showed:①Nitrophosphate,urea+NH_4H_2PO_4 and urea +superphosphate gave significant effect of increasing the production of spring wheat,and there was no considerable difference among these fertilizers. ②The utilization rates of spring wheat for fertilizer nitrogen were no signifi- cant difference among these fertilizers,but the utilization percent for various nitrogen forms in fertilizers had small differences.The rice growing after spr- ing wheat absorbed 22.1% of nitrogen from urea+superphosphate higher than that from nitrophosphate (15.5%),but there were little differences among the utilization percent of rice for various nitrogen forms in fertilizers.③The ni- trogen of fertilizers resided in soil after wheat in uea+NH_4H_2PO_4 and urea+ superphosphate were 52.9% and 52.1% respectively,both of which were higher than nitrogen in nitrophosphate (49.4%).Among various nitrogen forms,the urea nitrogen was the highest,then the NO_2^--N,the lowest one wao nitrogen of NH_4H_2PO_4.The residual rates of various nitrogen form in fertilizers after the scend crop fluctuated around 1.0%.④The loss rates of ferti]izer-N in the period of spring wheat growing ranged 12.0% to 24.5%,and in the period of rice grown after wheat hrvesting wese from 20.0% to 30.0%.It can be concluded from this result that the nitrophosphate and urea cannot be applied to crop with too high application rate for avoiding economical loss.⑤ The utilization percent of rice grown after vetch for fertiliger-N was 0.8～1.1%.