两种保护性耕作对土壤养分、结构和产量的影响

Effects of Conservation Tillages on Soil Nutrients,Structure and Crop Yield

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)。

Base d on the long-term experimental stations in Jingzhou and Wuxue of Hubei Province, this research investigated the effects of two conservation tillages(straw returning, no-tillage) combined with potassium fertilizer on soil physical and chemical properties in the different soil layers(0 ~ 20 cm and 20 ~ 40 cm) considering the different rotation systems and experimental periods. Results showed that soil nutrient contents were significantly higher in the 0~ 20 cm layer than that in the 20 ~ 40 cm layer of soil, No significant differences in soil nutrient contents between different treatments were found in the 20 ~ 40 cm layer of soil. In the 0 ~ 20 cm layer of soil, straw returnig,no-tillage and potassium fertilizer increased the contents of soil nutrient and the percentage of >0.25 mm water stable-aggregates. There were no significant differences between treatments in the 20 ~ 40 cm layer of soil. Straw returning reduced by 5% of soil bulk density, increased the total soil porosity, aeration porosity, capillary porosity, soil water content, and the ability of holding water. However, the opposite results were found in no tillage. Potassium fertilizer had no significant effects on bulk density and soil porosity. The yields of rape were significantly increased in straw returning and potassium fertilizer(by 18%), but not in no-tillage. The yields of rape had significant positive correlations with available potassium and organic carbon, correlation coefficient, respectively, 0.989 and 0.963, in the0 ~ 20 cm layer of soil.