有机-无机肥配施下氮钾的渗漏损失

A STUDY ON THE LEACHING LOSSES OF NITROGEN AND POTASH UNDER MIXED APPLICATION OF ORGANIC AND INORGANIC FERTILIZERS

连续3年5季的试验观测结果表明,稻季渗漏水中的氮以NH_4-N为主,麦季以NO_3-N和NO_2-N为主。稻季渗漏水中氮素形态的变化还因配施比例、烤田措施而变化。稻季渗漏损失的氮素主要来源于土壤氮,其中施肥的激发矿化作用对土壤氮的损失有较大影响。肥料氮直接渗漏的比例占26％～34％。稻季氮素渗漏损失量,在前期(拔节前)占全生育期总渗漏量的86％～90％,全期渗漏损失量占施氮量的18.2％～5.6％。随有机肥氮比例的增加而减少。稻季钾素渗漏量平均占施钾量的13％。肥料钾的直接渗漏损失占总渗漏钾量的75％左右。

Results obtained showed that NH_4-N was a main form in the percolated water collected in the growing season of rice, whereas NO_3-N and NO_2-N in the water were main form in the growing season of wheat. Results of ^(15)N isotopic determination showed that 66%～74% of N in percolated water came from native soil N and 26%～34% of N in the water derived from fertilizer N, Soil N losses from leaching were related with the priming mineralization of N caused by application of fertilizers. The leaching losses of N before internode elongation stage amounted to 86%～90% of the total leaching N in the whole growing season of rice, while the total leaching N corresponded to 18.2%～5.6% of the amounts of total applied N, and the leaching losses of N were decreased with the rate of organic N applied to soils. On the average, total leaching K was 13% of the amounts of applied K and the K losses derived from potassium fertilizers accounted for 75% of total leaching K in the growing seasons of rice.