The Approaches To Increase Wheat Yield And Fertilizer Use Efficiency By Reducing Chemical Fertilizer Inputs And Wide Drilling Sowing In Weibei Dryland

The Weibei dryland is an important wheat producing area in the central part of loess Plateau.However,there are some problems in the production,such as large amount of fertilizer application and unstable wheat yield,which lead to resource waste and soil quality degradation.To respond to the zero-growth policy of chemical fertilizer in China,alleviate the environmental pressure caused by excessive fertilization,improve the quality of wheat population,establish appropriate fertilization and supporting cultivation technology,and realize the efficient utilization of water and fertilizer resources and improve wheat yield,three field experiments were carried out in Yongshou County,Weibei dryland from 2019 to 2021.The effects of different sowing methods and fertilization modes on soil moisture,population dynamics,yield and yield composition,nutrient absorption characteristics and fertilizer utilization rate of winter wheat were analyzed.The main results were as follows.1.The treatment of wide drilling sowing(WS)can effectively use the precipitation and soil moisture.Compared with conventional drilling sowing treatment(CS),WS significantly reduced water consumption by 19.5% and 14.8% in early stages(sowing stage to reviving stage and reviving stage to jointing stage),improved soil deep water storage(120-200 mm)by5.6% and 7.5% in reviving stage and jointing stage.It can also provide water for the reproductive growth of winter wheat.Besides,WS can effectively improve precipitation production efficiency and water use efficiency by 2.9% and 4.6%,respectively.2.The treatment of WS can effectively improve the population quality and population quantity of winter wheat.Wide drilling sowing(WS)was beneficial to tillering of winter wheat,increasing tillering number by 0.7 per plant at reviving stage.It promoted dry matter accumulation of shoot by 17.30% and 5.81%,respectively at flowering and maturity stage of winter wheat compared with conventional drilling sowing.3.Under the experimental conditions,WS significantly increased the yield and biomass of winter wheat by 14.7% and 18.4%,and increased the spike number,kernel number and1000-grain weight of winter wheat by 7.6%,6.8% and 4.1%,respectively compared with CS.Meanwhile,the partial productivity of N,P,K fertilizer was increased by 15.4%,16.1% and13.5%,respectively and the N use efficiency of N,P,K fertilizer was increased by 0.34,1.9and 29.5 percentage points,respectively.4.Compared with farmer’s practice(FP)treatment,the treatment of soil test-based fertilization(ST)had no significant effect on wheat population quality and population dynamics(total stem number per unit,leaf area index and dry matter weight of winter wheat),and it also had no significant effect on nutrient uptake of wheat during the wheat growth period.5.Compared with the farmer’s practice(FP)treatment,the wheat yield of ST and soil test-based slow-release fertilization(STS)was slightly decreased under the wide-width drilling condition but there was no significant effect under the conventional drilling sowing condition.In addition,reduced fertilizer application can effectively improve the fertilizer use efficiency of winter wheat,among which,the partial productivity of nitrogen and phosphorus fertilizer of STS treatment was increased by 1.5% and 95.0%,respectively compared with FP treatment.Compared with the FP treatment,the fertilizer use efficiency of N and P fertilizer in the ST treatment was increased by 10.7 and 4.8 percentage points,respectively;the fertilizer use efficiency of N and P fertilizer in the STS treatment was increased by 5.7 and 9.6percentage points,respectively.6.The population dynamics and yield of winter wheat were significantly affected by the application of nitrogen fertilizer under both wide-width and conventional drill sowing conditions.In the treatment of free of N,P or K fertilization,the P-free(ST-P)and K-free(STK)treatment had no significant effects on total stem number per unit,leaf area index(LAI)and dry matter accumulation of winter wheat,while the N-free(ST-N)treatment significantly reduced total stem number per unit,leaf area index(LAI)and dry matter accumulation of winter wheat at each growth stage.The yield,biomass,spike number and kernel number in ST-N and ST-P treatments were lower than those in the ST treatment,especially in the ST-N treatment.In conclusion,for the winter wheat production in Yongshou County,reasonable fertilizer reduction treatment can effectively improve fertilizer utilization efficiency.The WS treatment can effectively utilize precipitation and soil water,improve winter wheat population quality and population number,increase yield and biomass,and improve fertilizer utilization rate.Therefore,the combination of wide drilling sowing and soil test-based fertilization can improve water and fertilizer utilization rate and grain yield,which can be popularized in winter wheat production in Weibei dryland.