稻麦轮作条件下施用氮肥对土壤供氮能力的影响

应用淹水密闭培养法评价了不同施肥处理对土壤供氮能力的影响。研究发现经过6年的轮作施肥,增施氮肥能够提高土壤的供氮能力及可矿化氮在土壤全氮中的比例。在淹水培养中,高施肥量土壤的氮矿化过程符合对数函数方程,而低施肥量和不施肥土壤符合直线方程。酸解氮和热氯化钾提取氮与土壤可矿化氮的相关性好于全氮、有机质和碱解氮,是良好的土壤供氮能力指标。

Effects of Applications of N Fertilizer on Soil Nitrogen Supplying Capacities under the conditions of Rice and Wheat Rotation

The effects of fertilization on soil nitrogen supplying capacit ie s were studied by the submerged incubation method. Results showed that the appl ication of nitrogen fertilizer after six years in rice and wheat rotation system enhanced soil nitrogen supplying capacities and the ratio of mineralizable nitr ogen to the total nitrogen. Under continuously waterlogged incubation conditions , the mineralization processes of soil organic nitrogen could be described by a logarithm function in the plots treated with very high dosages of nitrogen ferti lizer, while it could be described by a linear equation in the untreated control plots and the plots given smaller dosages. Hydrochloric acid-hydrolyzable nitro gen and hot KCL-hydrolyzable nitrogen were better correlated with soil mineraliz able nitrogen than total nitrogen, soil organic matter and NaOH-hydrolyzable nit rogen ,which were better soil nitrogen supplying indexes.