Effects Of Different Cultivation Methods On Growth And Water-nitrogen Use Efficiency Of Winter Wheat

North China Plain(NCP)is an important grain production base and the most important main production area of winter wheat in China.The production of winter wheat in this region is of great significance to China's food security.In recent years,many scholars have tried to introduce,improve and develop new cultivation methods of winter wheat,and explored more high-yield and high-efficiency cultivation methods to adapt to the development of regional water-saving and high-efficiency green agriculture.Therefore,three cultivation methods(Traditional cultivation,raised bed cultivation,high and low seed bed cultivation,referred as TC,RC,and HLSC)and three irrigation quotas(90 mm,72 mm,and 54 mm)were set,and the field experiment was carried out for 3 years.The temporal and spatial distribution of soil water and inorganic nitrogen,growth index,grain yield,water and nitrogen uptake and utilization efficiency of winter wheat under different cultivation methods and irrigation levels were systematically analyzed to explore the mechanism of increasing yield and efficiency of the new cultivation methods,and to determine the suitable cultivation methods and irrigation schemes in the NCP.The main results are as follows:(1)Under the same irrigation parameters,both RC and HLSC methods effectively improved the water advancing speed and irrigation uniformity compared with TC.Among them,RC method had the highest water advancing speed and irrigation uniformity,while HLSC method had the highest irrigation efficiency.After irrigation,topsoil water content of the ridge of RC(RC-R)and the high bed of HLSC(HLSC-H)was significantly lower than that of TC.Except for the topsoil,the soil water distribution of same soil layer in RC-R and the furrow of RC(RC-F)was consistent,while that in HLSC-H and the low bed of HLSC(HLSC-L)was consistent,and were both consistent with the TC method.Under the same cultivation mode,increasing irrigation quota could effectively improve the soil water content in 0-150 cm soil layer.(2)Cultivation method had significant effect on the distribution of soil NO3--N.From jointing to harvest stage,the NO3--N content in RC-R was significantly lower than that in the same soil layer of RCF,and NO3--N content in HLSC-H was significantly lower than that in the same soil layer of HLSC-L.Compared with TC and RC methods,the NO3--N residues in soil of HLSC at harvest time were significantly reduced.There was no significant difference in NH4+-N content in soil under different cultivation methods and irrigation levels(except on the 5th day after topdressing),and the NH4+-N nitrogen content in the 0-150 cm soil layer during the whole growth period of wheat was at a relatively low level(less than 3 mg kg-1).(3)Compared with TC method,HLSC method significantly increased tiller number,leaf area index(LAI),aboveground biomass and grain yield of winter wheat,while RC method had the lowest LAI,biomass and grain yield.The grain yield of HLSC increased by 22.63%,10.30%and 9.96%in three growing period,respectively,compared with the TC method.Under the same cultivation mode,increasing irrigation quota was conducive to improving LAI,abovemental biomass and grain yield of winter wheat,and the growth index and grain yield reached the maximum at irrigation quota of 90 mm.(4)HLSC method promoted more utilization of soil water storage in winter wheat,especially deep soil water storage.Although the total water consumption of HLSC method was significantly higher than that of TC,the water use efficiency(WUE)and water use efficiency of biomass(WUEAB)of HLSC method increased by 4.66%and 22.72%,respectively,compared with that of TC.The total water consumption,WUE and WUEAB of RC method were minimum.Under the same cultivation mode,WUE and WUEAB tended to decrease with the increase of irrigation quota,and reached the maximum when irrigation quota was 72 mm or 54 mm.(5)Compared with TC method,HLSC method significantly increased the nitrogen accumulation,nitrogen use efficiency(NUE)and nitrogen partial factor productivity(NPFP)of winter wheat,respectively by 21.76%,52.82%and 14.30%.The nitrogen accumulation,NUE and NPFP were reduced by RC method compared with TC method.The nitrogen accumulation,NUE and NPFP increased with the increase of irrigation water,and reached the maximum when irrigation quota was 90 mm or 72 mm.(6)The combination of HLSC pattern and irrigation quota of 90 mm significantly improved irrigation efficiency and increased tiller numbers,LAI,aboveground biomass,grain yield,water use efficiency,plant N accumulation,NUE and NPFP of winter wheat,and was an ideal high-yield and high-efficiency cultivation mode and irrigation quota in the study area.