Effect Of Planting Patterns And Types Of Nitrogen Fertilizer On Growth And Water And Nitrogen Use Efficiency Of Winter Wheat

The semi-humid drought-prone region is an important food production area in China.The uneven distribution of precipitation in all seasons,water shortage and area-source pollution caused by lower nitrogen use efficiency are serious constraints to the agricultural development in this region.Mulching film and applying slow-release nitrogen fertilizer are important agrotechnical measures in modern agricultural production.However,at present,when the planting patterns(especially the colors of the mulch)are combined with the types of nitrogen fertilizer,the coupling of water,heat and fertilizer affects the effect of winter wheat production is still unclear.The aim of this research was to screen out suitable combinations of planting patterns and types of nitrogen fertilizer to improve soil water,heat and fertilizer conditions and to increase winter wheat yield and water and nitrogen use efficiency.The experiment was conducted in a split-plot design with"Xiaoyan 22"winter wheat variety as the test crop from October 2018 to June 2019 at the Irrigation Experiment Station of the Key Laboratory of Agricultural Soil and Water Engineering in the Dry Zone,Ministry of Education,Northwest Agriculture and Forestry University of Science and Technology.The main plot of the test area was planting pattern:flat cropping without film,ridges covered with white film,and ridges covered with black film;the subplot was nitrogen fertilizer type:without nitrogen fertilizer,slow-release nitrogen fertilizer,and normal nitrogen fertilizer,total 9 treatments.The results of the tests revealed that:(1)The choice of without nitrogen fertilizer application under ridges covered with the planting pattern of ridges covered with black film maximized soil water storage in the 0～200cm soil layer,which increased by 4.02～25.21%(18.59～73.74 mm)compared with the flat cropping without film+slow-release nitrogen fertilizer treatment,which had the lowest soil water storage.The soil temperature of the ridge film furrow sowing treatment increased by0.43～2.12°C from seedling stage to filling stage compared to the flat cropping without film treatment.In the seedling stage,the average soil temperature at 5～25 cm depth was 0.40°C higher in ridges covered with white film treatment than in ridges covered with black film treatment.From the jointing stage to the filling stage,the average soil temperature at 5～25cm depth was 0.34～1.03°C higher in ridges covered with black film treatment than in ridges covered with white film treatment.(2)Ridges covered with white film+normal nitrogen fertilizer treatment effectively increased plant height,leaf area index,chlorophyll content,maximum photochemical efficiency of PSII,potential activity of PSII and the photochemical quenching parameter(q L)at the seedling stage of winter wheat.After jointing of winter wheat,the above mentioned indexes of ridges covered with black film+slow-release nitrogen fertilizer treatment began to dominate,which effectively promoted the nutritional and reproductive growth of winter wheat after jointing and was important for the formation of winter wheat yield.The highest mean value of non-photochemical quenching parameter(NPQ)was found in the flat cropping without film+without nitrogen fertilizer treatment during the whole reproductive period of winter wheat,with low leaf light energy conversion efficiency and photosynthetic electron transfer efficiency,which were not conducive to dry matter accumulation and yield formation of winter wheat.(3)At the seedling stage of winter wheat,the soil water and heat conditions of ridges covered with white film treatment and the fast dissolving characteristics of common nitrogen fertilizer increased the number of effective tillers,resulting in higher effective spikes per unit area.The highest dry matter accumulation at maturity,1000-grain weight,grains per spike and yield were recorded in ridges covered with black film+slow-release nitrogen fertilizer treatment,which increased 72.67%(6580.73 kg/hm~2),36.61%(12.87 g),26.67%(9.33 grains)and 87.02%(3955.04 kg/hm~2),respectively,compared with the lowest treatment of flat cropping without film+without nitrogen fertilizer treatment.(4)Ridges covered with black film treatment could effectively reduce the soil water storage consumption of winter wheat and increase the uptake and utilization of rainfall.The yield and water and nitrogen utilization efficiency of ridges covered with black film+slow-release nitrogen fertilizer treatment were significantly higher than other treatments,which can be regarded as a suitable combination of planting pattern and nitrogen fertilizer type intercropping for high yield and high water and nitrogen utilization of winter wheat in semi-humid drought-prone areas.The findings of this study have some theoretical value and practical significance for the efficient use of rainfall in winter wheat in semi-humid drought-prone areas,the improvement of monopoly film furrow sowing technology and the full effect of slow-release nitrogen fertilizer.