适宜种植密度和施氮量对提高冬小麦产量和水氮利用效率的影响

    Effects of suitable fertilizer-N application rate and planting density on increasing yield, water and nitrogen use efficiency of winter wheat

    • 摘要: 针对西北地区干旱以及不合理的施氮和种植密度导致的冬小麦产量和水氮利用效率偏低的问题,探究垄膜沟播模式下冬小麦高产和水氮高效利用的最优氮肥密度管理措施。试验设置150 kg/hm2(D1)、187.5 kg/hm2(D2)、225 kg/hm2(D3)3个密度梯度和180 kg/hm2(N1)、270 kg/hm2(N2)、360 kg/hm2(N3)3个施氮水平(以N计),通过2 a(2021—2022年和2022—2023年)田间试验,研究氮密互作对冬小麦生理生长、干物质累积、产量、水分利用效率(water use efficiency,WUE)和氮利用效率(nitrogen partial factor productivity,NPFP)的影响。结果表明:与当地常规氮密处理(D1N3)相比,合理增大种植密度和减少施氮量可使提高抽穗期LAI,使最大干物质累积量和累积速率分别增大147.25%和65.29%。2 a产量均在D2N2处理达到最大,平均值11911.93 kg·/hm2,但2 a WUE分别在D2N2和D2N3达到最高,NPFP分别在D2N2和D3N1处理最高。通过拟合分析,2021—2022年冬小麦产量、WUE和NPFP达到最大值时所对应的种植密度与施氮量分别为195.92和260.82 kg/hm2、200.51和249.80 kg/hm2、195.92和187.35 kg/hm2,2022—2023年分别为195.92和257.14 kg/hm2、194.39和286.53 kg/hm2、197.45和183.67 kg/hm2。基于回归模型对产量、WUE和NPFP进行综合评价,最终确定种植密度180.45~190.04 kg/hm2、施氮量201.66~256.67 kg/hm2的组合模式为垄膜沟播冬小麦高产和水氮高效利用的氮密管理措施。研究结果可为西北地区冬小麦的高产高效栽培提供理论依据。

       

      Abstract: The ridge film and furrow sowing model has been widely used in the arid region of northwest China, in order to solve the problems of low yield , water and nitrogen use efficiency of winter wheat caused by drought, and unreasonable nitrogen application rate and planting density in northwest China, we explored the optimal nitrogen fertilizer and density management for high yield and efficient use of water and nitrogen of winter wheat in the ridge mulching and furrow sowing mode. Three density gradients of 150 kg/hm2 (D1), 187.5 kg/hm2 (D2) and 225 kg/hm2 (D3) and three nitrogen application rate of 180 kg N/hm2 (N1), 270 kg N/hm2 (N2) and 360 kg N/hm2 (N3) were set in the experiment. In a two-year field experiment (2021-2022 and 2022-2023), taking “Xiaoyan 22” as the test variety, to study the effects of different nitrogen and density treatments on the physiological growth, aboveground dry matter, yield, water and nitrogen use efficiency of winter wheat. Study the following conclusions are obtained: leaf area index (LAI) and aboveground dry matter accumulation showed a parabolic trend with the increase of nitrogen application rate or planting density, compared with local conventional nitrogen and density treatment (D1N3), reasonably increasing planting density and decreasing nitrogen application could increase LAI at the tasseling stage, and the maximum dry matter accumulation and accumulation rate by 147.25% and 65.29%. With the increase of soil depth, the soil moisture content increased at jointing stage, but decreased then increased at heading stage and filling stage. The average soil water content of 100 cm soil layer in 2 years was the highest in D3N3 and D1N3, respectively. Chlorophyll content reaches the maximum at heading stage, the suitable nitrogen and density management increased the chlorophyll content by 0.53%-31.25%. The interaction between nitrogen fertilizer and density had significant (P<0.001) effects on yield, water and nitrogen use efficiency. Reasonable density and nitrogen management measures are conducive to the increase of yield and water and nitrogen use efficiency. Excessive nitrogen application rate or excessive planting density had certain inhibitory effects on crop growth. With the increasing of planting density or nitrogen application, the yield and water use efficiency (WUE) showed a tendency of increasing and then decreasing, and the yield reached the maximum in the D2N2 treatment, with a two-year average of 11911.93 kg/hm2. Based on the regression model, comprehensive evaluation of yield, WUE and NPFP, the optimization conditions were 95% of the maximum value of yield and WUE, 85% of the maximum value of NPFP, the combination pattern of planting density of 180.45-190.04 kg/hm2 and nitrogen application rate of 201.66-256.67 kg/hm2 was finally determined as the nitrogen and density management measures for high yield and nitrogen efficient utilization of ridge mulching and furrow sowing winter wheat, it realized the synergistic improvement of yield and resource utilization efficiency to the maximum extent. The results of the study can provide practical guidance and theoretical basis for the high yield and efficiency cultivation of winter wheat in Northwest of China.

       

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