淹水土壤微生物生物量的形成与肥料氮的转化——盆栽试验

SOIL MICROBIAL BIOMASS FORMATION AND FERTILIZER N TRANSFORMATION UNDER SUBMERGED CONDITIONS ——POT EXPERIMENT

在盆栽条件下研究施用稻草粉对水稻土土壤微生物生物量的形成与肥料氮的转化的影响。施用稻草粉可降低水稻对肥料氮的吸收，提高对非肥料氮的吸收；施用稻草粉可提高肥料氮的残留率，降低肥料氮的损失。至水稻收获时，残留于土壤中的１５Ｎ主要以生物量及其代谢产物－Ｎ形态存在于土壤中。生物量及其代谢产物－Ｎ的形成因土壤不同而有快慢之差，但其再矿化速度都较为缓慢。即使在稻草粉施用量较高的情况下也未观察到水稻吸氮总量受到明显的影响。

A pot experiment was conducted to further investigate the soil microbial biomass formation and fertilizer N transformation in submerged soils as affected by rice straw incorporation Results showed that rice straw incorporated decreased the N uptake by rice plant from 15 N labelled fertilizer while 15 N residue in soil and the N uptake by rice plant from non labelled N were increased Fertilizer N loss was reduced by the incorporation of rice straw By the time of harvest, most of the residue 15 N in soil was in the form of microbial biomass and associated metabolites 15 N There was small amount of 15 N labelled N in the fixed form The rate of microbial biomass formation varied with soils Although the soils used had different ammonium fixation capacities, it seemed that ammonium fixation capacities of the soils did not affect nitrogen immobilization