绿洲灌区水氮减施密植玉米的光合源动态和产量表现

为进一步探索河西绿洲灌区玉米在水、氮减量的条件下能否支撑较高的种植密度而获得高产,本研究通过大田试验,设置传统灌水(W1)和生育期减量20%灌水(W2)2个灌水梯度,高施氮(450 kg·hm^-2,N1)、减量30%施氮(300 kg·hm^-2、N2)2个施氮水平和D1(7.5万株·hm^-2)、D2(9.75万株·hm^-2)、D3(12万株·hm^-2) 3个种植密度,在不同种植密度条件下,采用水氮耦合组合,测定玉米生育期内光合源动态、干物质积累、籽粒产量和产量性状。结果表明,在生育后期W2N2玉米光合势(LAD)与W1N1无显著差异,在W2N2条件下,D2的LAD较D1在玉米全生育期内平均增加8.7%,D2与D3之间无显著性差异;在W2N2条件下,玉米干物质积累量最终与W1N1持平,D2干物质积累量较D1在玉米全生育期内平均增加21.1%,D2与D3之间无显著性差异;D2玉米籽粒产量在W2N2与W1N1间保持同等水平,较D1玉米籽粒产量提高9.0%~33.7%;灌水和施氮因素对玉米穗粒数和千粒重影响均不显著,而在同等水、氮条件下,D3玉米穗粒数较D1降低了5.9%~26.1%,千粒重降低了9.2%~12.3%。综上,D2水平使减量灌水、减量施氮条件下的玉米在生育后期仍然保持较大的LAD,为玉米产量的形成提供了物质保障,从而获得高产。本研究结果为通过水氮减施实现资源节约的高效农业生产提供了技术参考。

Photosynthetic Source Dynamics and Yield Performance of High Density Maize With Reduced Amount of Water and Nitrogen in Oasis Irrigation Region

In order to further explore the higher density of maize in Hexi Oasis Irrigation Area, whether high yield can be obtained under the condition of water and nitrogen reduction, the photosynthetic potential, dry matter accumulation, grain yield and yield composition of maize during growth period were determined. The field experiment designed traditional irrigation (W₁) and growth period reduction 20% irrigation (W₂), high nitrogen application (450 kg·hm^-2, N₁), reduction of 30% nitrogen application (300 kg·hm^-2, N₂) and three planting density of 75,000 plants·hm^-2 (D₁), 97,500 plants·hm^-2 (D₂) and 120,000 plants·hm^-2 (D₃). The results indicated that no significant difference was found in the photosynthetic potential of W₂N₂ and W₁N₁ corn in the late growth stage. Under the W₂N₂ treatments, the photosynthetic potential of D₂ increased by 8.7% compared with D₁ during the whole growth period of the maize. There was no significant difference between D₂ and D₃. The dry matter accumulation of W₂N₂ was eventually equal to W₁N₁ at a low amount of water and nitrogen conditions. The dry matter accumulation of D₂ increased by 21.1% compared with D₁ during the whole growth period of maize and no significant difference was found between D₂ and D₃. The grain yield of W₂N₂D₂ was the same with that of W₁N₁D₂. The dry matter accumulation of D₂ increased by 9.0%~33.7% compared to that of D₁ treatment. Irrigation and nitrogen applications had no significant effect on the grain number per ear and 1000-grain weight of maize. Under the same water and nitrogen conditions, the grain number of D₃ corn compared with D₁ decreased by 5.9%~26.1%, and the 1000-grain weight of corn decreased by 9.2%~12.3%. In conclusion, W₂N₂D₂ still maintained a large photosynthetic potential of maize under reduced irrigation and nitrogen application at the later stage of growth, which provides material guarantee for the formation of corn yield, thus obtaining high yield. Therefore, maize planting with plant density of 97,500 plants per hm^-2 in a condition of reduced 20% irrigation and 30% nitrogen application can be recommended as a technical reference.