Coupling Effects Of Water And Nitrogen On Wolfberry In Qaidam Basin Under Drip Irrigation

At present,the amount of nitrogen applied in the wolfberry planting areas in the Qaidam Basin is relatively large,the efficiency of water and fertilizer utilization is low,and the resources are wasted seriously.In order to solve the above problems,the effects of different water and nitrogen ratios on the soil moisture,nutrients,and growth and yield,quality and economic benefits of wolfberry were studied by setting different irrigation amounts and different nitrogen application rates under drip irrigation conditions.Exploring and optimizing the application mode of water and fertilizer in the local wolfberry planting,so as to save the local wolfberry planting cost,improve the economic benefits of wolfberry production,increase farmers'income,and reduce agricultural pollution.A two year?2018-2019?experiment were conducted continuously in the field in2018-2019,using an orthogonal combination design of two factors of water and nitrogen,in which the water settings were set to three levels of W0(198 m³·ha^-1),W1(158 m³·ha^-1)and W2(119 m³·ha^-1).nitrogen?urea?settings were set to three levels of N0(345 kg·ha^-1),N1(276 kg·ha^-1)and N2(207 kg·ha^-1),with the local irrigation nitrogen application?CK?as contrast,to study the effects of different water-nitrogen coupling ratios on soil moisture,nutrients,wolfberry growth,yield,WUE,and fruit quality.The results showed that:?1?Effects of water and nitrogen coupled drip irrigation on soil moistureDifferent coupling ratios of water and nitrogen had a direct impact on the water absorption capacity of wolfberry,and then affected the soil moisture content and soil water storage of each soil layer.The soil water storage of W1N1 treatment was significantly higher within two years.After 2018 and 2019,the soil water storage was 34.43%and 5.06%higher than that of CK treatment.The soil water storage of the 0-100 cm soil layer in two years showed a consistent law:the soil water storage of each treatment has increased in each period,the soil water storage in the summer fruiting periods increases faster,but the soil water storage in the autumn fruiting period increases slower.?2?Effects of water and nitrogen coupled drip irrigation on soil nutrients and growth of wolfberryThe W1N1 and W1N2 treatments are more suitable for plants to absorb and utilize soil nutrients,and the plant growth state is better.Among them,the nitrate nitrogen content in the roots of wolfberry treated by W1N2 was reduced by 8.12%within two years,and the ability of plants to transform and utilize NO₃-N in soil was stronger;the plant height and crown width of W1N1 treatment were significantly higher than that of CK treatment within two years,and the highest reached 134.27 cm and 123.57 cm.?3?Effects of water and nitrogen coupled drip irrigation on fruit yield,quality and WUECombined with the statistics of two years,the W1N1 treatment has better fruit yield and quality.The average fresh fruit yield reached 8926.5 kg·ha^-1 within two years,an increase of46.23%compared with the CK treatment.The fruit commodity and medicinal quality of W1N2 treatment were significantly higher;with an average of 45.41 g·kg^-1 in two years;considering the fluctuation of the wolfberry market,the W1N1 treatment has the best economic benefit,and the net income per hectare reached about 36,000 yuan.A comprehensive analysis of the experiment results led to the following research conclusions:For the wolfberry plantation site in the Qaidam Basin,under irrigation conditions,the irrigation water volume was 158 m³·ha^-1and the nitrogen application volume was 276 kg·ha^-1,which combination may be a better water and fertilizer model for local wolfberry cultivation.