硝酸铵在旱地土壤中后效的研究

本文采用玉米、高梁~(15)N示踪微区试验,对硝酸铵在白浆土、草甸黑土、淡黑钙土上施用的后效与残留分布进行了研究,结果表明:硝酸铵在三类土壤上施用,当年的残留氮平均占施入氮量的15～30％,施后第2、3年分别为12～22％,8～10％。在各类土壤中的残留量,三年结果都是白浆土>淡黑钙土>草甸黑土。残留氮集中分布在0～40cm的土层中,其量占残留氮量的84～93％,只有7～16％分布于40cm以下的土层中。硝酸铵施后三年总利用率平均为61.21％,硝酸铵施后第2、3年的总利用率为2.12％。硝酸铵有明显后效。

STUDY ON THE RESIDUAL EFFECT OF AMMONIUM NITRATE AppLIED TO UpLAND SOILS

The study of the distribution and effect of the residual N of ammonium nitrate applied to Albic soil, Meadow phaiozem, Ochroschernozems was conducted through 15N-tracer microplot experiments, with corn and sorghum as indicating crops. The result showed that: The. average residual N in three sorts of soil to which ammonium nitrate had been applied was 15-30% of the total N-application in the first year, and was 12-22% and 8-10% in the second and the third year respectively. The amount of residual N in three sorts of soil was Albic soil> Ochros-cherno-zems> Meadow phaiozem. The residual N remained mainly in the top soil (0-40cm) , the amount of residual N in 0-40cm top soil was 84-93% of the total amount of residual N, the amount of residual N in the subsoil (>40cm) took only 7-16%. The total efficiency of ammonium nitrate applied to upland soils in three years averages 61.21%, the total efficiency of residual N of ammonium nitrate in the second and the third year was 2.12%. There were evidently residual effect of ammonium nitrate.