氮肥对垄沟集雨种植谷子氮素利用效率及产量的影响

The Effect of Nitrogen Fertilizer on Nitrogen Use Efficiency and Yield of Foxtail Millet in Ridge-Furrow Rainwater Harvesting Planting Model

【目的】探究垄沟集雨种植模式下谷子的生长、产量对氮肥的响应,以期为黄土高原半干旱区谷子高产高效生产提供理论依据。【方法】于2022—2023年选用陕豫谷3号谷子品种进行大田试验,采用裂区设计,主因素为种植模式(垄沟集雨种植模式,R;传统平作种植模式,T),副因素为施氮量(0 kg·hm^(-2),N0;60 kg·hm^(-2),N1;135 kg·hm^(-2),N2;210 kg·hm^(-2),N3),在不同种植模式下测定谷子旗叶净光合速率、叶绿素相对含量、各生育时期地上部群体干物质积累量、氮素积累量,以及成熟期农艺性状和产量,并计算氮素利用率。【结果】同一施氮量下,与传统平作种植模式相比,垄沟集雨种植模式下谷子旗叶的净光合速率、叶绿素相对含量在降雨较多的2022年仅灌浆期有所提高,在降雨较少的2023年抽穗期、开花期、灌浆期则均有提高,两年间垄沟集雨种植模式均增强了谷子生育中后期的光合能力,延缓叶片衰老;谷子地上部群体干物质积累量、氮素积累量在2022年的拔节期、灌浆期、成熟期有所提高,在2023年各生育时期均有增加,且N1、N2、N3间均无显著性差异,地上部干物质积累量、氮素积累量分别提高了0.6%—39.5%、0.9%—51.1%;籽粒氮素积累量、花后氮素积累量、花后氮素对籽粒贡献率在两年间均有显著增加,满足了谷子全生育期的养分需求,改善了传统平作种植模式下谷子生育后期氮肥供应不足问题;氮肥偏生产力在两年间均有增加,分别提高了3.7%—14.3%、2.8%—27.6%,氮肥农学利用效率在2022年于210 kg·hm^(-2)施氮量下略有降低,氮肥农学利用效率、氮肥利用效率在2023年施氮量超过135 kg·hm^(-2)时均有所降低,三者均随施氮量的增加而降低;谷子穗粗、单穗重在两年间均有提高,穗长则有所下降;产量在两年间均有显著性提高,分别增加了3.7%—14.3%、2.8%—27.6%,在降雨较少的2023年增产效果更为显著,且当施氮量超过60 kg·hm^(-2)时,产量无显著性增加。【结论】在黄土高原半干旱区,垄沟集雨种植模式配施60—135 kg·hm^(-2)氮肥更有利于谷子氮素利用和产量形成。

【Objective】To explore the response of foxtail millet growth and yield to nitrogen fertilizer under ridge-furrow harvesting planting model,in order to provide a theoretical basis for high yield and efficient production of foxtail millet in the semi-arid regions of the Loess Plateau.【Method】Shaan-Yugu No.3 variety was selected for field experiments from 2022 to 2023,and split plot design was adopted.The main plot were different planting models(Ridge-furrow rainwater harvesting planting model,R;Traditional plain planting model,T),and the sub-plot were different nitrogen application levels(0 kg·hm^(-2),N0;60 kg·hm^(-2),N1;135 kg·hm^(-2),N2;210 kg·hm^(-2),N3).The net photosynthetic rate and chlorophyll content of flag leaves of foxtail millet,dry matter accumulation and nitrogen accumulation of aboveground population at different growth stages,agronomic traits and yield at maturity stage,and nitrogen utilization rate were measured under different planting models.【Result】Under the same nitrogen application rate,compared with the traditional plain planting model,the net photosynthetic rate and chlorophyll content of flag leaves under the ridge-furrow rainwater harvesting planting model increased only at the filling stage in 2022 with more rainfall and increased at the heading,flowering,and filling stages in 2023 with less rainfall.The ridge-furrow rainwater harvesting planting model enhanced the photosynthetic capacity of foxtail millet in the middle and later stages of growth and delayed leaf senescence during the two years.The dry matter accumulation and nitrogen accumulation of the aboveground population of foxtail millet increased during the jointing,filling,and maturity stages in 2022,and increased at all growth stages in 2023.There was no significant difference between N1,N2,and N3,and the aboveground dry matter accumulation and nitrogen accumulation increased by 0.6%to 39.5%and 0.9%to 51.1%,respectively.The grain nitrogen accumulation,post-flowering nitrogen accumulation,and post-flowering nitrogen contribution rate to grain have significantly increased over the past two years,meeting the nutrient needs of foxtail millet throughout its entire growth stage and improving insufficient nitrogen supply in the later growth stage of foxtail millet under traditional plain planting model.Nitrogen partial productivity increased between two years,increasing by 3.7%to 14.3%and 2.8%to 27.6%,respectively.Nitrogen agronomic efficiency slightly decreased at a nitrogen application rate of 210 kg·hm^(-2) in 2022,while the nitrogen agronomic efficiency and nitrogen use efficiency both decreased when the nitrogen application rate exceeded 135 kg·hm^(-2) in 2023.Meanwhile,nitrogen partial productivity,nitrogen agronomic efficiency,and nitrogen use efficiency decreased with the increase in nitrogen application rate.The ear diameter and single ear weight of foxtail millet increased between two years,while the ear length decreased.The yield has significantly increased between two years,increasing by 3.7%to 14.3%and 2.8%to 27.6%,respectively.The yield increase effect was more significant in 2023 with less rainfall,and there was no significant increase in yield when the nitrogen application rate exceeded 60 kg·hm^(-2).【Conclusion】In the semi-arid regions of the Loess Plateau,the ridge-furrow rainwater harvesting planting model combined with 60 to 135 kg·hm^(-2) nitrogen fertilizer is more beneficial to the nitrogen utilization and yield formation of foxtail millet.