Effects Of Mulching Mode And Nitrogen Rate On Water-Nitrogen-Light Utilization And Grain Yield Of Dryland Summer Maize

Dryland farming agriculture plays an important role in ensuring national food security and agricultural development,but the sustainable production of dryland agriculture is seriously threatened by insufficient rainfall and poor soil.Soil mulching and nutrient management can improve grain yields and resource use efficiency,which is important for regional food security and green agricultural development.In this study,summer maize(Zhengdan 958)was tested in the irrigation experimental Station of the Key Laboratory of Agricultural Soil and Water Engineering in Arid Regions of the Ministry of Education in Northwest A&F University from June to October 2021 and 2022.The mulching modes(NM: flat planting without mulching;SM: flat planting with straw mulching;RP1: ridge-furrow mulching;FM1: flat planting with transparent film mulching;RP2: ridge-furrow mulching with black film mulching;FM2: flat planting with black film mulching)and nitrogen application rate(N0:0 kg/ha;Effects of N1:180 kg/ha)on soil water and heat status,growth,physiological characteristics,grain filling process,yield and water-nitrogen-light use efficiency of dryland summer maize.The main results are as follows:(1)The effects of different mulching modes on soil temperature and moisture in summer maize fields were revealed.For 0-25 cm soil temperature,transparent film had a significant warming effect,while black film and straw showed a calming effect on soil temperature,and the soil temperature of each treatment was FM1 > RP1 > NM > RP2 > SM > FM2.The soil moisture content varies with the growth period and the influence of rainfall,and the overall pattern is mulching >straw > bare land.In mulching treatment,the whole mulching is usually higher than ridge furrow,and after rainfall,the ridge furrow is higher than the whole mulching due to the rain collecting effect of ridge furrow,but there is no significant difference between different mulching colors.(2)The effects of different mulching modes and nitrogen application rates on the growth and physiological characteristics of summer maize were clarifiedMulching was beneficial to the growth of summer maize(plant height,stem diameter,leaf area index,above-ground dry matter accumulation),which was RP > FM > SM,and black film > transparent film.Nitrogen application could significantly improve the growth indexes of summer maize.The relative chlorophyll content,net photosynthetic rate,maximum photochemical quantum efficiency of PSⅡ,steady-state photochemical quantum efficiency and photochemical quenching coefficient of summer maize increased first and then decreased from joint stage to grouting stage,and reached the maximum value at tasseling stage.The physiological indexes were RP > FM > SM > NM under different mulching treatments,and black mulching film was better than transparent film,but there was no significant difference between different mulching film colors.Nitrogen application significantly improved the physiological indexes of summer maize,and the improvement effect in 2021 was significantly better than that in 2022.(3)The effects of mulching modes and nitrogen application rate on grain filling process and yield of summer maize were investigatedMulching can promote the grain filling process of summer maize,improve the filling rate and grain weight at each stage of the filling stage,prolong the duration of the fast filling period,and ultimately improve the grain yield of summer maize.Grain filling parameters and grain yield under each mulching treatment were RP > FM > SM > NM,and black film > transparent film.Compared with NM treatment,SM,RP1,FM1,RP2 and FM2 treatment increased grain yield by 7.23 %,33.85 %,23.43 %,42.13 % and 27.68 %,respectively.Nitrogen application had significant effects on grain filling process and yield related characters of summer maize.Compared with N0,the grain yield of summer maize treated with N1 increased by 38.39 % on average.(4)The effects of mulching mode and nitrogen application rate on water,nitrogen and light use efficiency of summer maize were expoundedMulching can reduce water consumption and improve water use efficiency of summer maize during its growth period.Compared with NM treatment,the water use efficiency of SM,RP1,FM1,RP2 and FM2 treatments increased by 12.45 %,50.50 %,43.19 %,59.36 % and48.28 %,respectively,and the improvement effect in dry years was better than that in wet years.Nitrogen application could improve the water use efficiency of summer maize.Compared with N0,the water use efficiency of N1 treatment was increased by 30.41 % on average.Compared with traditional plain cropping without mulch,soil mulching increased nitrogen uptake,nitrogen harvest index and nitrogen use efficiency of summer maize.Compared with NM treatment,the N use efficiency of SM,RP1,FM1,RP2 and FM2 treatments was increased by 2.77 %,9.21 %,5.18 %,10.81 % and 6.66 %.Nitrogen application could reduce nitrogen use efficiency of summer maize.Compared with NM treatment,the light use efficiency of SM,RP1,FM1,RP2 and FM2 treatment was increased by 2.07 %,18.35 %,10.74 %,21.48 % and 11.91 %,respectively.Compared with N0,the light energy utilization efficiency of N1 treatment was increased by 24.74 % on average.In conclusion,compared with traditional plain cropping without mulching,surface mulching can effectively promote the growth of summer maize,improve yield and waternitrogen-light use efficiency by regulating soil moisture and temperature.Mulching film is better than straw mulching,furrow mulching film is better than no mulching film,black mulching film is better than transparent mulching film.Nitrogen application could also significantly improve the yield and water-light utilization efficiency of summer maize.