Effects Of Tillage Modes On Soil Water And Nitrogen Distribution And Winter Wheat Yield Under Fixed Sprinkler Irrigation

This study was conducted to investigate the effects of Tillage Modes on the distribution characteristics of water and nitrogen in soil and crop yield,in addition to exploring suitable tillage modes under sprinkler irrigation conditions.Field experiments were conducted to set rotary tillage(RT),subsoiling(ST)and conventional tillage(CT)during the winter wheat growing season in 2017-2019,on three plots of 18 m×18 m.Each plot was subdivided into 9subplots of 6 m×6 m.The effects of different tillage methods on the spatial and temporal distribution of soil moisture,nitrate nitrogen,and ammonium nitrogen under sprinkler system with permanent pipe,as well as the effects on winter wheat yield and water and nitrogen use efficiency were studied.The main findings are as follows:1 Effects of tillage modes on winter wheat yield and economic benefitsDifferent tillage treatments had significant effects on winter wheat yield.In two years,compared with RT treatment,the yield of ST and CT treatment increased by 7.01% and 9.21%,respectively.Among them,the effective spike number increased by 11.70% and 3.73%,grain number per spike increased by 8.17%,15.54%,but the 1000 weight grain decreased by12.34% and 8.99%.The ST and CT treatments increased the effective spike number and grain number per spike of winter wheat,and thus increased the yield,and its economic benefits increased by 10.50% and 13.21% compared to RT treatment.2 Effects of tillage modes on soil water distribution and water use efficiencyThe tillage method has a significant effect on the spatial and temporal distribution of soil moisture.The average value of the uniform coefficient of spray irrigation has fluctuated between 63.91% and 76.83%.Due to the redistribution of irrigation water,the average value of the uniform coefficient of water content in the surface layer is between 84.20% and 89.83%.The average value of the uniformity coefficient of water content is about 20% higher than sprinkler irrigation.Among three treatments,the soil uniformity coefficient of ST treatment increased the largest compared with irrigation uniformity coefficient.During the growth period of winter wheat,the average soil water content in the 60~100cm soil layer of ST and CT treatments was higher than RT treatment 9.86% and 3.65%,respectively,which improved the water storage capacity of deep soils.The ST and CT treatments are beneficial to the growth of winter wheat roots due to the deep plowing layer,and have higher soil water consumption and water use efficiency than RT treatments.Compared with RT treatment,the water use efficiency of ST and CT treatments increased by7.41% and 9.08%,respectively.3 Effects of tillage modes on soil inorganic nitrogen distribution and nitrogen useSoil nitrate nitrogen and ammonium nitrogen were randomly distributed in the horizontal direction of each plot,and showed no regularity.The content of nitrate nitrogen and ammonium nitrogen in the soil after irrigation had a corresponding relationship with that before irrigation.And its distribution uniformity coefficient has been improved to varying degrees.In each treatment,the content of soil nitrate nitrogen increased to varying degrees in the range of 0~40 cm soil layer.The content of soil nitrate nitrogen in RT treatment was significantly lower than that in ST and CT treatments.The content of soil nitrate nitrogen decreased first and then increased in the 0~100 cm soil layer.However,the soil ammonium nitrogen was distributed in a wave shape,and there was no significant difference between the treatments.As the growth period advances,the uniformity of soil nitrate nitrogen and ammonium nitrogen were decreasing.In the mature period of winter wheat,ST and CT treatments significantly increased The round of N accumulation,nitrogen partial productivity,and nitrogen harvest index compared with RT treatment.,which helped to get higher yields to some extent.Comprehensive two-year test,due to the redistribution of water,the uniformity coefficient of soil water content after irrigation was significantly higher than that of sprinkler irrigation,and the uniformity coefficients of soil nitrate and ammonium nitrogen also increased to varying degrees than before irrigation under the fixed sprinkler irrigation.ST and CT treatments improved the ability of deep soil water retention capacity,higher winter wheat yield,improved water use efficiency and partial nitrogen fertilizer productivity,and higher economic benefits.ST and CT treatments were suitable farming modes in the North China Plain under sprinkler system with permanent pipe.