不同有机肥培肥对旱作农田土壤团聚体的影响

Effects of different organic manure with fertilization on soil aggregates in dry farmland

【目的】研究不同有机肥施用量和玉米秸秆还田量对土壤团聚体组成和有机质含量的影响。【方法】在渭北旱塬连续3年(2007-2009年)进行有机培肥定位试验,以不施肥处理为对照,研究施用不同量秸秆(9 000、13 500kg/hm2)和有机肥(鸡粪,15 000、22 500kg/hm2)后,不同土层(0～10,10～20cm)土壤团聚体组成和有机质含量的变化。【结果】9 000,13 500kg/hm2秸秆还田和15 000,22 500kg/hm2有机肥处理0～20cm土层土壤有机质含量分别较对照提高了8.92%(P<0.05),9.85%(P<0.01)和7.41%(P<0.05),12.03%(P<0.01)。施用有机肥处理和秸秆还田处理0～20cm土层粒径>0.25mm机械稳定性团聚体含量显著高于对照(P<0.05)。粒径>0.25mm水稳定性团聚体含量随秸秆还田和有机肥施用量的增加而增大,高秸秆和高有机肥处理较对照差异显著(P<0.05)。干筛法测定的土壤团聚体平均质量直径极显著高于对照(P<0.01)。土壤团聚体分散度和不稳定团粒指数在0～20cm土层表现为高秸秆和高有机肥处理较对照明显降低。不同培肥处理粒径≤5～>2和≤1～>0.5mm水稳定性团聚体含量与有机质含量呈极显著正相关关系。【结论】有机培肥可以显著提高粒径>0.25mm机械稳定性团聚体和水稳定性团聚体含量及有机质含量,有机培肥通过提高有机质含量直接促进了渭北旱塬土壤粒径≤1～>0.5mm水稳定性团聚体的形成,对旱地土壤理化性质具有一定的改善作用。

【Objective】 The influences of different amounts of organic manure and straw returning to soil aggregates and organic matter were analyzed.【Method】 Three successive years（2007-2009）of positioning experiments were carried out in Weibei Loess Plateau.Compared with that treated with no fertilizer in the 0-10 and 10-20 cm layer,soil aggregates and organic matter of different application rates of straw（9 000,13 500 kg/hm2） and organic manure（15 000,22 500 kg/hm2） were determined.【Result】 Compared with CK0,straw returning and organic manure treatments organic matter contents increased by 8.92%（P0.05）,9.85%（P0.05） and 7.41%（P0.05）,12.03 %（P0.01） in 0-20 cm soil depth.When we applied organic manure and straw,0.25 mm mechanical stability aggregates contents were higher than CK0 in 0-20 cm depth（P0.05）.The contents of 0.25 mm water-stable aggregates were enhanced with the increase of the weight of organic manure and straw returning,higher straw returning and organic manure treatments were significantly higher than CK0＇s（P0.05）.Soil MWD under dry sieving method were significantly higher than CK0＇s（P0.01）.Soil aggregates dispersion rate and the index of unstable aggregates showed that higher straw returning and higher organic manure were clearly lower than CK0 in 0-20 cm depth.The contents of 1-0.5 mm and 5-2 mm water-stable aggregates and organic matter contents had a significant positive correlation.【Conclusion】 Using organic fertilizers improved the amount of 0.25 mm mechanical aggregates,0.25 mm water-stable aggregates and organic matter,the organic matter directly contributed to 1-0.5 mm water-stable aggregates formation in Weibei Loess Plateau,and had certain improvements on the physical and chemical properties in dry farmland.