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在湖北省武穴市和荆州市的长期定位试验基础上,研究不同水旱轮作制度和试验周期下,两种保护性耕作措施(秸秆还田、免耕)及配施钾肥对于不同土层(0~20 cm和20~40 cm)农田土壤养分和结构的影响。结果表明:(1)在两个地区,0~20 cm土层土壤中各养分含量均显著高于20~40 cm土层,且20~40 cm土层土壤中各处理之间变化规律不明显。在0~20 cm土层土壤中,免耕、秸秆还田以及施用钾肥均能有效提高土壤中各养分含量;(2)免耕、秸秆还田以及施用钾肥均能提高0~20 cm土层土壤>0.25 mm水稳性团聚体的百分含量,且各处理的提高效果不尽相同。但是在20~40 cm土层土壤中,各处理之间没有明显规律;(3)秸秆还田能够减小土壤容重(减小5%),增加0~20 cm土层土壤总孔隙度,通气孔隙度,毛管孔隙度和土壤含水量,并增强土壤保持水分的能力。免耕处理效果却相反,施用钾肥处理的容重和孔隙度没明显变化;(4)秸秆还田和配施钾肥均能够显著增加油菜产量(增产了18%),免耕处理却不然。油菜产量和0~20 cm土壤养分(速效钾、有机碳)显著正相关(相关系数分别是0.989和0.963)。
Based on the long-term experiment of Wuxue and Jingzhou in Hubei Province, the effects of two conservation tillage practices (returning straw to tillage and no tillage) and applying K fertilizer on different soil layers 0 ~ 20 cm and 20 ~ 40 cm) on farmland soil nutrient and structure. The results showed that: (1) The nutrient contents of 0 ~ 20 cm soil layer were significantly higher than those of 20 ~ 40 cm soil layer in both areas, while the changes in the soil layers of 20 ~ 40 cm soil layer were not obvious . No-tillage, straw-returning and applying potassium fertilizer could effectively increase soil nutrient content in 0-20 cm soil layer. (2) No-tillage, straw-returning and potash application could increase 0-20 cm soil layer Soil> 0.25 mm water-stable aggregate percentage, and the effect of each treatment is not the same. However, there was no obvious regularity among the treatments in 20-40 cm soil layer. (3) Straw returning reduced soil bulk density (5%), increased total soil porosity and aeration in 0-20 cm soil layer Porosity, capillary porosity and soil moisture, and enhances soil’s ability to retain moisture. However, the no-tillage treatment had the opposite effect. There was no significant change in the bulk density and porosity of the treated K application. (4) Both straw addition and potash fertilization could significantly increase the yield of rapeseed (18% yield increase), while the no tillage treatment did not. The yield of rapeseed was significantly and positively correlated with 0-20 cm soil nutrient (available potassium and organic carbon) (correlation coefficients were 0.989 and 0.963, respectively).