不同增氧水平对夏玉米生长及氮素利用的影响

为探究有利于夏玉米生长和氮素利用的适宜灌溉水溶解氧浓度,本试验以夏玉米为供试作物,采用地下滴灌供水方式,以地下水灌溉为对照,设置10(OA10)、20(OA20)和40(OA40) mg·L^-1灌溉水溶解氧浓度3个增氧水平,研究不同增氧水平对盆栽夏玉米生长、产量和氮素利用的影响。结果表明,增氧地下滴灌显著提高了土壤溶解氧浓度,与对照相比,OA40、OA20和OA10处理土壤溶解氧浓度平均提高14.83%、9.71%和8.00%,表现为作物生长增强,作物产量和氮素利用效率均显著提高(P<0.05)。与对照相比,OA10处理的株高、叶鲜质量和叶干质量分别增加7.39%、16.30%和12.02%;OA40处理叶干质量和茎鲜质量分别增加15.82%和12.43%;OA10、OA20和OA40根系鲜质量分别增加60.00%、17.66%和52.98%,根系体积分别增加34.03%、14.56%和51.32%;OA10和OA20处理根系活力分别增加272.77%和64.44%;OA10和OA40处理产量分别增加24.46%和21.83%,水分利用效率分别提高19.10%和21.61%,百粒重分别增加17.53%和15.14%。OA10和OA40处理籽粒氮素吸收量较对照分别增加63.90%和35.27%,OA10处理籽粒氮素分配比例和氮素吸收效率分别增加21.57%和33.33%。上述差异均具有统计学意义(P<0.05)。综上,增氧地下滴灌可显著提高作物根区溶解氧浓度,促进作物生长,提高产量及氮素吸收利用,以OA10处理效果最为显著。本研究结果为增氧灌溉技术在实际生产中的合理利用提供了理论依据。

Impacts of Different Dissolved Oxygen Levels in Aerated Irrigation Water on Summer Maize Growth and Nitrogen Utilization

The summer maize was adopted as test crop in this work to investigate suitable dissolved oxygen concentrations for the benefits of crop growth and nitrogen utilization. With the strategy of subsurface drip irrigation and the control treatment (CK) of groundwater irrigation, impacts of aerated irrigation on potted maize growth, yield and nitrogen utilization were analyzed by setting three dissolved oxygen concentrations in irrigation water as 10 (OA10), 20 (OA20) and 40 (OA40) mg·L^-1. The results evidenced that the dissolved oxygen concentration in soil was significantly promoted by aerated subsurface drip irrigation. Compared to CK, the soil dissolved oxygen in OA10, OA20 and OA40 treatments increased by 14.83%, 9.71% and 8.00% on average, respectively, leading to remarkable improvements in crop growth, yield and nitrogen use efficiency (P<0.05). Specifically, the plant height, leaf fresh weight and leaf dry weight enlarged by 7.39%, 16.30% and 12.02% in OA10, the leaf dry weight and stem fresh weight elevated by 15.82% and 12.43% in OA40, the root fresh weight in OA10, OA20 and OA40 increased by 60.00%, 17.66% and 52.98%, and the root volume enhanced by 34.03%, 14.56% and 51.32%; the root activity in OA10 and OA20 boosted by 272.77% and 64.44%; the crop yield in OA10 and OA40 raised by 24.46% and 21.83%, the water utilization efficiency improved by 19.10% and 21.61%, the 100-seed weight progressed by 17.53% and 15.14%. The grain nitrogen uptake in OA10 and OA40 increased by 63.90% and 35.27%, and the grain nitrogen partitioning ratio and nitrogen uptake efficiency in OA10 grew by 21.57% and 33.33%. All differences above were statistically significant (P<0.05). Thereby, the aerated subsurface drip irrigation elevated the oxygen concentration in the root zone of the crop dramatically and hence facilitated the crop growth, yield and nitrogen uptake and usage. Herein, the optimist improvement was observed in OA10. This study provides a theoretical basis for applications of the aerated irrigation technique.