Regulation Technology For Increasing Yield And Efficiency Of Dryland Spring Maize On The Loess Plateau

The shortage of water resources is the main factor limiting crop yield in arid and semi-arid areas of Northwest China,and surface mulching technologies are effective measures to improve crop yield and water use efficiency in this area.However,under mulching conditions,how to regulate fertilizer application to increase nutrient use efficiency and maintain soil fertility is also a technical problem to be further studied.This study aims to increase the yield and water and nutrient efficiency of spring maize in the arid area of Northwest China.By setting different technical measures to regulate water use（no mulching B,straw mulching S and plastic film mulching F）and nutrient use（no nitrogen fertilizer N0,1:2 combined application of controlled release urea and conventional urea N1 and conventional urea N2）,the single cropping system of spring maize on the Loess Plateau was taken as the research object.The regulatory effects of different surface mulching and nitrogen application techniques and their interaction on the yield,nutrient and water absorption and utilization of spring maize were studied in order to construct the technology of increasing yield and increasing efficiency of dryland spring maize.To achieve a balanced crop yield and improve fertilizer and water use efficiency in the semi-arid region of the Loess Plateau to provide a certain scientific basis.The main results are as follows:1. Plastic film mulching（F）and nitrogen application increased the chlorophyll content（SPAD）of spring maize leaves. Under the condition of nitrogen application,compared with no mulching（B）and straw mulching（S）,plastic film mulching significantly increased the SPAD value of leaves at ten-leaf stage,silking stage and milk stage.Under different mulching,compared with no nitrogen application（N0）,1:2 combined application of controlled release urea and conventional urea（N1）and conventional urea（N2）treatments significantly increased the SPAD value of spring maize leaves,and the increment increased with the growth period.2. Different mulching patterns and nitrogen application significantly increased the leaf area index（LAI）and dry matter accumulation of spring maize in the main growth period of the experiment.The LAI and dry matter accumulation of the treatments treated with controlled release urea and conventional urea（N1）and conventional urea（N2）were significantly higher than those without nitrogen application.Under the two nitrogen application conditions,compared with no mulching and straw mulching treatments,plastic film mulching treatment increased dry matter accumulation,and the increase was mainly in the V10～R1 and R3～R6 stages.3. Spring maize at 1:2 combined with controlled release urea and common urea with plastic film mulching（FN1）had the highest yield,yield components and harvest index of treated.Under different surface mulching conditions,compared with N0 treatment,N1 and N2 treatments significantly increased the yield,ear number,grain number per ear and100-grain weight of spring maize.Under the conditions of plastic film mulching,non-mulching and straw mulching,the grain yield of spring maize treated with N1 were10.22 t.hm^-2,8.53 t.hm^-2,8.71 t.hm^-2higher than that of N0;compared with N0 treatment,the grain yield of spring maize under N2 treatment was significantly increased by 9.27t.hm^-2,8.4 t.hm^-2and 8.51 t.hm^-2,respectively.Under the condition of nitrogen application,the grain yield,ear number and 100-grain weight of spring maize treated with plastic film mulching were significantly higher than those without plastic film mulching and straw mulching.4. Nitrogen application significantly increased grain and shoots P and K uptake,P and K physiological efficiency of spring maize under different surface mulching,but there was no significant difference between N1 and N2 treatments.Different surface mulching had different effects on phosphorus and potassium uptake and utilization of spring maize:it significantly affected grain phosphorus uptake,shoots phosphorus uptake（P<0.01）,100kg grain phosphorus demand and phosphorus physiological efficiency（P<0.01）.However,it had no significant effect on grain potassium uptake,shoots potassium uptake,100 kg grain potassium demand and potassium physiological efficiency of spring maize（P>0.05）.5. Nitrogen application significantly increased water consumption,grain and biomass water use efficiency of spring maize under different surface mulching treatments. Under the same mulching condition,the water consumption of two kinds of nitrogen application（N1,N2）treatment in PT-R6 period was significantly higher than that of non-nitrogen application treatment by 9.24%and 13%.Under 1:2 combined application of controlled release urea and conventional urea,the grain water use efficiency of plastic film mulching treatment（FN1）was the highest(46.06 kg ha^-1mm^-1),which was significantly higher than that of straw mulching（SN1）and non-mulching（BN1）treatments.In conclusion,plastic film mulching at 1:2 combined with controlled-release urea and conventional urea not only achieved high yield,but also increased grain water use efficiency and phosphorus absorption and utilization of spring maize.It is a better regulation technique for increasing yield and efficiency of dryland spring maize under the experimental conditions on the Loess Plateau.