不同生产目标下农牧交错带燕麦生产的最优水氮组合

Optimal combination of water and nitrogen for oat production under different production goals in the agro-pastoral ecotone

[目的]北方农牧交错带地区长期面临水氮管理混乱和片面追求高产的问题,基于不同生产目标优化水氮耦合方案,对建立燕麦绿色高效生产体系具有重要意义。[方法]选择北方农牧交错带为研究区域,基于北方农牧交错带典型站点(河北省张家口市张北县)开展的燕麦水氮耦合大田试验数据校正APSIM-Oat模型,基于充分校正的AP-SIM-Oat模型在区域尺度上推荐该地区燕麦不同生产目标的最优水氮耦合方案。[结果]北方农牧交错带地区燕麦不同生产目标下水氮投入差异较大,W_(90)N_(150)(灌溉90 mm,施氮量150 kg·hm^(-2))或W_(120)N_(150)组合(灌溉120 mm,施氮量150 kg·hm^(-2))情景下燕麦产量最高,1780~3190 kg·hm^(-2),东部和中部地区高于西部地区。降低水氮投入可进一步提高氮肥利用效率,获得最高氮肥利用效率的水氮耦合方案为W_(30)N_(30)(灌溉30 mm,施氮量30 kg·hm^(-2)),最高氮肥利用效率区域平均值为33.7 kg·hm^(-2)·kg^(-1),东部氮肥利用效率高于中部和西部地区。降低灌溉投入,保持氮肥投入燕麦可获得最大收益,W_(60)N_(150)(灌溉60 mm,施氮量150 kg·hm^(-2))或W_(90)N_(150)组合(灌溉90 mm,施氮量kg·hm^(-2))情景下燕麦收益最高,为2940~6700元·hm^(-2),中部地区种植燕麦收益高于东部和西部地区。[结论]与获得最高产量水氮投入相比,减少灌溉(降低60~90 mm)和氮肥(降低120 kg·hm^(-2))可获得最高氮肥利用效率;施氮量保持不变,灌溉投入降低30~60 mm,可获得最高收益。

[Objective]The management of water and nitrogen for oat production in the northern agro-pastoral ecotone in China has often been inconsistent,with a focus mainly on maximizing yield.Optimizing irrigation and nitrogen inputs based on specific production goals is essential for developing a sustainable and efficient oat production system.[Method]In this study,27 study sites were selected across the agro-pastoral ecotone.A field experiment examining the combined effects of water and nitrogen on oat yield was carried out in Zhangbei county,followed by calibration of the APSIM-Oat model using the experimental data.The fully calibrated model was then used to simulate various water and nitrogen coupling scenarios across the study region,allowing for recommendations on the optimal irrigation and nitrogen combinations tailored to different production goals.[Results]The combination of W_(90)N_(150)(90 mm irrigation with 150 kg·hm^(-2) Nitrogen)or W_(120)N_(150)(120 mm irrigation with 150 kg·hm^(-2) Nitrogen)produced the maximum oat yield ranging from 1780 to 3190 kg·hm^(-2),with the lowest yields observed in the western APE.For maximum nitrogen use efficiency,the W_(30)N_(30)(30 mm irrigation with 30 kg·hm^(-2) Nitrogen)combination was optimal,achieving an average efficiency of 33.7 kg·hm^(-2)·kg^(-1),with the highest efficiency in the eastern region.The highest economic returns were achieved with the W_(60)N_(150)(60 mm irrigation with 150 kg·hm^(-2) Nitrogen)or W_(90)N_(150)(90 mm irrigation with 150 kg·hm^(-2) Nitrogen)combinations,ranged from 2940 to 6700 CNY·hm^(-2),with the middle region showing the highest returns.[Conclusion]Compared to the inputs needed for maximum yield,reducing irrigation by 60~90 mm and nitrogen by 120 kg·hm^(-2) achieved maximum nitrogen use efficiency.Additionally,maintaining nitrogen levels while reducing irrigation by 30~60 mm maximized income.