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Response of water coupling with N supply on maize nitrogen uptake, water and N use efficiency, and yield in drip irrigation condition.

GUO Bing-yu, GAO Hui, TANG Cheng, LIU Tao, CHU Gui-xin   

  1. (College of Agronomy, Shihezi University/Xinjiang Production and Construction Group Key Laboratory of Oasis Ecological Agriculture, Shihezi 832003, Xinjiang, China)
  • Online:2015-12-18 Published:2015-12-18

Abstract: Water and nitrogen are two major limiting factors for upland crop growth and development in arid region. Optimizing regulation irrigation schedule, rates and coupling with N fertigation is an effective way for realizing crop production improvement as well as water and nutrient use efficiency enhancement. In the present study, a field trial was carried out to study the influence of water (4500, 6750, 9000 m3·hm-2) coupling with N (0, 225, 330, 435, 540 kg·hm-2) supply on maize dry matter accumulation, N uptake, yield and nitrogen fertilizer use efficiency in drip irrigated high cultivated density (≥105000 plant·hm-2) condition. There was an obvious tendency that the amounts of corn dry matter accumulated and plant N absorbed increased with levels of water and N supply, however, those decreased gradually when the N applied rate beyond 435 kg·hm-2 and irrigation level above 9000 m3·hm-2. For instance, the effect of irrigation level on corn dry matter accumulation order exhibited W6750 (36359 kg·hm-2)>W9000(35077 kg·hm-2)> W4500 (33451 kg·hm-2), the sequence of amount of N absorbed showed N435(462.0 kg·hm-2) > N540 (459.4 kg·hm-2)> N330 (423.4 kg·hm-2)> N225(348.1 kg·hm-2), the amount of N absorbed in N435 treatment increased by 9.1% and 32.7%, respectively, in contrast with treatments of N330 and N220, whereas, the amount of N absorbed in N540 decreased by 0.6% than that in N435 treatment. The highest N absorption rate increased with N application rate increasing within N supply range of 0-435 kg·hm-2, it reached peak value of 6.57 kg·hm-2·d-1 at N application rate of 435 kg·hm-2, then had decline trend with increasing N rate. Both irrigation and N supply exerted a significant role on maize yield as well as yield component of kernel number per spike and kernel mass per spike. An obvious positive interaction was obtained between water and nitrogen; moreover, the effect of N on yield was substantially higher than that of irrigation. N fertilizer use efficiency increased with  increasing N level within N supply range of 0-435 kg·hm-2, and then dropped markedly when N rate above 435 kg·hm-2. It was found that the water productivity of irrigation (WP#em/em#) increased with  increasing N level, while, that decreased with  increasing irrigation rate. At the suitable irrigation range of 4500-6750 m3·hm-2, the WPi of 2.57-3.80 kg·m-3 could be achieved. The maximum corn yield of 18072 kg·hm-2 was reached at N rate of 567.0 kg·hm-2. The best N rate of 427.9-467.7 kg N·hm-2 obtained the optimum yield of 17109-17138 kg·hm-2, with the nitrogen partial factor productivity of 122 kg N·hm-2 and nitrogen use efficiency of 45.0% reached. In sum, optimizing water coupling with N supply was the effective strategy for realizing corn yield improvement as well as resources of water and N use efficiency in drip irrigation condition in arid region.