氮肥施用方式对土壤有机质与氮素含量的影响

Effect of different Nitrogen Application Methods on Soil Organic Matter and Nitrogen Content

在秸秆还田条件下,研究了氮肥施用方式对白浆土有机质与氮素时空动态的影响。结果表明:在秸秆还田条件下,白浆土0～20 cm土壤有机质含量随生育进程呈增加的趋势,至收获期达到最大值,20～30 cm土壤于R4期达到最大值;白浆土全氮含量随生育进程呈单峰曲线,于R2～R4期达到最大值;碱解氮含量随生育进程呈单峰曲线,0～20 cm土壤于R5期、20～30 cm土壤于R2期达最大值。种肥施氮增加了0～20 cm土壤有机质含量,追施氮肥使10～30 cm土壤有机质含量增加;种肥施氮增加了R2期以前土壤全氮含量,追施氮肥对土壤全氮含量影响不明显;种肥施氮使20～30 cm土壤碱解氮含量降低,对0～20 cm土壤影响不大,追施氮肥使土壤碱解氮含量增加。白浆土有机质含量与全氮含量、有机质含量与碱解氮含量、碱解氮含量与全氮含量均呈极显著正相关。

Straw returning can reduce environmental pollution and improve the fertility of soil. The research investigated differ- ent nitrogen application methods on spatial and temporal dynamic of soil organic matter and nitrogen content under straw re- turning. On the condition of straw returning, 0 - 20 cm planosol organic matter increased with growing process, reached max- imum at harvest stage, 20 - 30 cm reached maximum at R4 stage; The content of planosol total nitrogen was expressed in a single peak curve with growing process, reached maximum at R2 - R4 stage; The content of planosol available nitrogen was expressed in a single peak curve with growing process, 0 - 20 cm soil reached maximum at R5 stage, 20 - 30 cm soil reached maximum at R2 stage. The content of 0 - 20 cm soil organic matter increased by the nitrogen fertilizer as seed manure, 10 - 30 cm soil organic matter content increased by nitrogen topdressing; The nitrogen applied as seed fertilizer increased soil total nitrogen content before R2 stage, while nitrogen topdressing had little effect on soil total nitrogen content. The nitrogen fertil- izer application as seed fertilizer decreased the content of 20 -30 cm soil available nitrogen, while it had little effect on 0 - 20 cm soil, soil available nitrogen content increased by nitrogen topdressing. The content of soil organic matter and total nitrogen, soil organic matter and available nitrogen, available nitrogen and total nitrogen of planosol showed a significantly positive correlation.