膜下滴灌条件下水氮调控对河套灌区春玉米产量及水氮利用效率的影响OA

To investigate the increasing effects of water and nitrogen regulation through mulched drip irrigation on spring maize yield in the Hetao Irrigation District,a meta-analysis was conducted with 399 sets of yield data,369 sets of water use efficiency(WUE)data,and 297 sets of partial factor productivity of nitrogen(PFPN)data from 40 publicly published studies meeting the criteria based on databases such as CNKI and Web of Science.The results showed that water and nitrogen regulation significantly affected spring maize yield,WUE,and PFPN.Compared with low water and low nitrogen(CK),increasing irrigation(medium water and low nitrogen,W2N1)increased the spring maize yield by 19.04％,whereas increasing nitrogen application rate(low water and high nitrogen,W1N2)increased the yield by only 5.94％.Excessive irrigation and nitrogen application caused water-nitrogen imbalance and subsequently decreased WUE,with the largest reduction observed under high water and high nitrogen(W3N2),being 10.07％lower than that under CK.Compared with CK,PFPN increased with the increase in irrigation amount with nitrogen application rate≤300 kg/km2,and the increments were 8.26％and 9.37％under W2N1 and W3N1(high water and low nitrogen),respectively.While PFPN decreased as the nitrogen application rate increased,with a 32.00％reduction under W1N2.Regulating irrigation amounts had greater effects on the yield increase and nitrogen utilization efficiency than adjusting nitrogen application.When the soil content of salt,organic matter or total nitrogen was relatively high,water and nitrogen regulation exerted a significant positive effect on spring maize yield,the yield-increasing effect decreased as the irrigation amount increased,and W2N1 resulted in yield increases by 37.71％,28.40％,and 27.12％compared with CK.As the annual precipitation or multi-annual mean temperature rose(annual precipitation＞156 mm or multi-annual mean temperature＞7 ℃),WUE declined with the increase in irrigation,excessive nitrogen application adversely affected PFPN,and WUE significantly decreased by 4.88％and 16.21％and PFPN declined by 38.12％and 38.72％under W3N2 compared with those under CK.Within similar ranges of water and nitrogen,appropriately increasing fertilization frequency or reducing irrigation quotas with reasonably adjusting planting density can significantly enhance the spring maize yield,leading to more efficient utilization of these resources.Comprehensively considering the yield-increasing effect and efficient utilization of water and nitrogen resources,the recommended ranges are 150 to 200 mm of irrigation and 180 to 220 kg/hm2 of nitrogen application rate in the Hetao Irrigation District.Under the comprehensive control conditions of planting density ≤6.66× 104 plants/hm2,irrigation quota≤30 mm,and fertilization frequency＞5 times,the yield of spring maize can reach 15 400 to 18 200 kg/hm2,with WUE ranging from 38.16 to 50.52 kg/(hm2 mm)and PFPN reaching 55.02 to 81.20 kg/kg.The study can provide reference for saving water,increasing the yield,and reducing nitrogen application in spring maize production in this area.