Effects Of Combined Application Of N,P,K On Spring Com Yield And Nitrogen Efficiency In Northern Shaanxi Sandy Land

Yulin,Shaanxi is located in the northern part of the Mu Us Desert,where water resources are scarce,annual precipitation is low,and evaporation is strong;soil is barren and soil erosion is severe,resulting in excessive fertilization and pressure on the ecological environment."Water and fertilizer integration technology"is the integration of irrigation and fertilization,which not only saves water and fertilizer,but also effectively improves crop yields.Under the general environment where the country intends to carry out the construction of the second granary along the Great Wall of Northern Shaanxi,it is necessary to deal with traditional crops on sandy land-corn To carry out experimental research on the integration of water and fertilizer.The field experiment of spring maize under drip irrigation mode in Shenmu,northern Shaanxi Province,using the three-factor D-saturation optimal design experiment,studied the different nitrogen,phosphorus and potassium formula fertilization on maize yield and corn at jointing,tasseling and harvesting The effects of organ dry matter quality,nitrogen distribution,and nitrogen in the root zone of the soil draw the following main conclusions:1. Combined application of nitrogen,phosphorus and potassium promotes plant growth best;the distribution law of dry matter mass in each organ is that the dry matter mass ratio of leaves gradually decreases with the growth period;The distribution of total dry matter increased gradually from the tasseling period to the harvesting period.2. Fertilization significantly increased the yield and increased by 32.60%?52.90%;after optimization of the yield model,the suitable local fertilization and combined application were:nitrogen fertilizer 240 kg/hm~2,phosphate fertilizer 77 kg/hm~2,potassium fertilizer 158kg/hm~2,and the output could reach 14,151 kg/hm~2.3. Nitrogen accumulation in the whole plant of maize during the growing period gradually increased.In the distribution of nitrogen in vegetative and reproductive organs,the nitrogen accumulation in leaves and stems gradually decreased with the growth period,and the grains gradually increased;The growth period gradually decreased,the change in stem proportion showed a decrease in the tasseling period,and a slight increase in the harvest period.Nitrogen application has a significant effect on nitrogen transport and vegetative organ contribution rate.4. Nitrogen application mainly affects the soil nitrate nitrogen content in the vertical direction of 0?40 cm soil layer;there is no obvious law in the horizontal direction;nitrogen application has no obvious law in the horizontal and vertical directions of ammonium nitrogen;compared with CK,Nitrate nitrogen and ammonium nitrogen contents of nitrogen treatment increased to varying degrees;soil nitrate nitrogen content gradually decreased with plant growth and absorption,ammonium nitrogen showed a decrease in the tasseling period,and a slight increase in the harvest period.