施肥措施对红壤结构的影响

Effect of application of fertilizers on soil structure in red soil.

利用长期定位试验研究红壤开垦利用后不同施肥措施下红壤结构的变化结果表明,红壤开垦利用后,>1mm机械稳定性大团聚体有所增加,而>1mm水稳定性团聚体含量有所下降,但施用有机肥可缓冲>1mm大团聚体含量下降的趋势,增加>0.25mm大团聚体总量。红壤开垦利用后土壤容重变小,土壤孔隙度增加。施用有机肥可使土壤毛管孔隙度增加50％,有效水库容增加64％,而施用化肥仅分别比荒草地红壤增加27％和33％。施用绿肥、稻草或秸秆还田有利于提高土壤的持水性能,而施用化肥对土壤持水性能似无明显改善作用。

Changes in physical structure of red soil were studied under different conditions of fertilizer application. The results showed that the content of>1mm mechanical-stable macro-aggregate was increased while the content of>lmm water-stable macro-aggregate decreased after red soil was cultivated,but applications of organic fertiliz-ers were beneficial to buffer the decline tendency of content of>1mm water-stable macro-aggregate, and to in-crease total macro-aggregate content of>0.25mm. Soil porosity was increased while soil bulk density was de-creased after red soil cultivated. Soil capillary porosity was increased by 50% ,and soil available water capacity in-creased by 64% under application of organic fertilizers, while application of chemical fertilizers only increased by 27% and 33% respectively. Meanwhile, there was a significant increase in soil reserving water capacity under appli-cation of organic fertilizers, but there was no significant difference between application of chemical fertilizers and uncultivated soil.