Effects of fertilization and plastic film mulched ridge-furrow cultivation on yield and water and nitrogen utilization of winter wheat on dryland

Water and nutrient are the major restriction factors for growth and development of winter wheat on dryland.Therefore,it is of great importance to study water-fertilizer interaction effects under the conditions of natural precipitation for increasing winter wheat yield,fertilizer utilization,soil productivity and improving soil structure on dryland.However,the water-fertilizer interaction effects were not only the coordination in quantity,but also closely related to crop growth stages.Meanwhile,interaction effects were all closely related to soil moisture and fertility,and changed with regional differences of soils and climate.So effects of fertilization and plastic film mulched ridge-furrow cultivation system on population dynamics,yield components and utilization of water and nitrogen of winter wheat on dryland were studied by field experiment in rain-fed growing areas in Xiangfen county,Shanxi province.The experiment consisted of 5 treatments,i.e.no nitrogen fertilization,conventional nitrogen fertilization,recommended fertilization,recommended nitrogen fertilization + top dressing and recommended nitrogen fertilization + plastic film mulched ridge-furrow cultivation.Potassium fertilizer was not applied in all treatments,rate of phosphate was 120 kg P2O5/hm2,and top dressing was carried out when rainfall happened at booting stage.Ridge width was 20 cm,ridge height was 6 cm and furrow width was 20 cm in plastic film mulched ridge-furrow cultivation system.There was no irrigation and the rainfall was 182.6 mm over the winter wheat growth season.Obtained results showed that both the plastic film mulched ridge-furrow cultivation and top dressing treatments promoted winter wheat spike number formatting evidently,which was around 4.6 million plants/hm2.Spike number and kernel number per spike were the key factors in increasing yield of plastic film mulched ridge-furrow cultivation and top dressing treatments on dryland;the invalid tillerings could be reduced by later top dressing.The yield of plastic film mulched ridge-furrow cultivation and top dressing treatments were 11.73% and 13.91% higher than that of conventional fertilization respectively.The plastic film mulched ridge-furrow cultivation could obviously reduce consumption of soil water,so the water consumed by plastic film mulched ridge-furrow cultivation was only 172.82 mm,which was the lowest among all treatments,and the water utilization efficiency of plastic film mulched ridge-furrow cultivation system was highest,being 11.60 kg · hm-2 · mm-1.The top dressing treatment promoted effectively soil water to be absorbed and utilized by winter wheat,with the water efficiency being 10.47 kg · hm-2 · mm-1,which was significant higher than that of both conventional nitrogen fertilization and recommended nitrogen fertilization.Therefore,to some extent,the plastic film mulched ridge-furrow cultivation and top dressing were important measures to increase water use efficiency and solve soil water shortages in arid regions.The top dressing also effectively promoted the nitrogen and utilization by winter wheat in medium-late growth period.The total absorption of nitrogen in aboveground part of winter wheat was increased by 15.45 kg/hm2,and the agronomic efficiency and apparent recovery efficiency of applied N by 20.6% and 106.1%,respectively by top dressing of 30 kg N/hm2 on the basic nitrogen application of 165 kg/hm2.The nitrogen use efficiency of top dressing was 51.5%,which was significantly higher than that of base fertilization.Therefore,plastic film mulched ridge-furrow cultivation and rational fertilizer top dressing according to the regularity of nitrogen requirement are the important measures for increasing yield and utilization of water and nitrogen of winter wheat on dryland.