A STUDY ON THE LEACHING LOSSES OF NITROGEN AND POTASH UNDER MIXED APPLICATION OF ORGANIC AND INORGANIC FERTILIZERS
Wu Shanmei, Liu Dehui, Ni Miaojuan, Sun Yuhua and Ranwei(Research Laboratory of farmland ecology)
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.
【CateGory Index】： S147.3