Effects of different tillage measures during summer fallow season on soil nutrient contents and enzyme activities in dryland wheat field
To explore the effects of different tillage measures during summer fallow season on soil properties and enzymes in soil of dryland winter wheat-summer fallow production system,a fixed field experiment(initiated in June 2018)of five tillage measures during summer fallow season was conducted at Xiaojie town,Luoning county,Henan province,a typical dryland at the intersection of Loess Plateau and Huang-Huai-Hai Plain.The tillage measures included conventional tillage(CT),once deep plowing tillage(DT),no-tillage with straw mulching(NTM),subsoiling with straw mulching(STM)and subsoiling plus ridge and furrow with straw mulching(SRFM).The three-phase ratios,nutrient contents and enzyme activities in soil in wheat field were investigated in 2020-2022.Optimized tillage measures during summer fallow season improved the ratios of three-phase and increased the nutrient contents and enzyme activities in soil of dry wheat fields,and SRFM had the best effect overall.Compared with CT,the soil three-phase ratios of STM and SRFM were significantly reduced by 4.7%-28.2%and 10.9%-33.7%,respectively.Compared with CT,in 0-40 cm soil layer under DT,STM and SRFM the total nitrogen content was increased by 2.8%-11.2%,11.7%~21.4%and 15.6%~30.6%,the available phosphorus content was increased by 6.9%-39.5%,7.4%-68.8%and 13.6%-80.3%,the available potassium content was increased by 5.2%-19.7%,9.6%-25.8%and 13.8%-35.0%,the invertase activity was increased by 7.8%-21.5%,17.1%-75.9%,and 27.9%-99.1%,the urea enzyme activity was increased by 7.6%-97.0%,12.8%-165.5%and 23.5%-194.9%,and the catalase activity was increased by 5.5%-15.2%,16.3%-26.7%and 20.8%-50.3%,respectively.Moreover,most of the increases reached a significant level and the performance was SRFM>STM>DT.Compared with CT,the nutrient contents and enzyme activities under NTM were significantly increased in 0-10 cm soil layer but decreased in 20-40 cm soil layer.Above all,the measure of subsoiling plus ridge and furrow with straw mulching during the summer fallow season should be recommend to improve soil quality in dryland wheat field because it can optimize the ratios of three-phase,improve soil nutrient contents and enzyme activities in soil.