旱地施有机肥对土壤有机质和水稳性团聚体的影响

Effects of organic manure application on dry land soil organic matter and water stable aggregates

通过渭北旱塬2007—2010年田间定位试验,研究了有机肥不同施用量(低量7500kg·hm-2、中量15000kg·hm-2、高量22500kg·hm-2)对连作玉米地土壤有机质、团聚体各层粒径分布和稳定性的影响.结果表明:0～20cm土层,高量有机肥处理土壤有机质含量较低量有机肥处理提高4.1%～4.6%,高、中量有机肥处理较对照提高4.6%～11.2%,低量有机肥处理在施肥第4年(2010年)较CK提高4.7%～6.3%.0～30cm土层,所有有机肥处理>5mm水稳性团聚体的增幅最大,其含量随有机肥用量的增加而显著升高;有机肥处理显著提高了土壤>0.25mm水稳性团聚体含量、团聚体平均质量直径和团聚体稳定率,且随有机肥用量的增加而显著增加;中、高量有机肥处理比单施化肥处理增加效果显著.

A four-year （2007-2010） field experiment was conducted to study the effects of applying different amounts （7500, 15000, and 22500 kg·hm-2） of organic manure on the organic matter content, aggregate particle size distribution, and aggregate stability in different soil layers in a continuously cropped maize field on the Weibei Dry Land, Shaanxi Province of Northwest China. In 0-20 cm soil layer, the organic matter content in treatment 22500 kg·hm-2 of organic manure was 4.1%-4.6% higher than that in treatment 7500 kg·hm-2 of organic manure （P0.05）, and the organic matter content in treatments 15000 and 22500 kg·hm-2 of organic manure was 4.6%-11.2% higher than that in CK （chemical fertilization） （P0.05）. In the fourth year （2010） of applying 7500 kg·hm-2 of organic manure, the organic matter content in 0-20 cm soil layer was 4.7%-6.3% higher than that of CK （P0.05）. In 0-30 cm soil layer, all treatments with organic manure application had an increased amount of soil water stable aggregates （5 mm）, and the amount of the aggregates increased significantly with the increasing application rate of organic manure. Applying organic manure increased the amount of soil water stable aggregates （0.25 mm）, aggregate mean mass diameter, and aggregate stability in 0-30 cm soil layer, as compared with CK, and these three indices increased significantly with increasing organic manure application rate.