基于APSIM模型分析不同降水年型下施氮深度对旱地小麦的产量效应

氮肥深施有助于提高旱地作物产量,但施氮深度对黄土高原丘陵沟壑区旱地小麦产量在不同降水年型的影响尚不清楚。利用1990—2020年气象观测数据,基于APSIM模型和数学统计方法探讨施氮深度对不同降水年型小麦产量的影响。结果表明:模型模拟的小麦产量和生物量模拟值与观测值相关性决定系数(R²)>0.9、模型有效性指数(M_E)>0.8及归一化均方根误差(NRMSE)<0.2,表明该模型在该地区具有较好的适用性;模拟的麦田生育期土壤水分动态变化和收获期土壤剖面含水量的NRMSE分别为0.05~0.07和0.13~0.29,表明该模型基本能够较准确模拟麦田土壤水分变化。氮肥深施增产效应在丰水年最高,平水年次之。与干旱年相比,相同施氮量下丰水年和平水年增加施氮深度可提高农田生产力稳定性和可持续性。在施氮水平为150 kg/hm²时,丰水年和平水年增加施氮深度对农田生产力稳定性没有明显影响,但有助于提高农田生产力可持续性。不同降水年型下,施氮深度和施氮量与产量交互关系表明,丰水年和平水年拟合关系较好,R²分别为0.76(P<0.05)和0.61(P<0.05),丰水年和平水年增加施氮深度至约20~23 cm可获得潜在最高产量。干旱年R²为0.29(P>0.05),增加施氮深度对干旱年小麦产量没有显著影响。研究结果以期为黄土高原丘陵沟壑区小麦在区域尺度优化施肥措施提供理论指导。

Analysis of Effects of Nitrogen Application Depths on Yield of Spring Wheat in Different Precipitation Years Based on APSIM Model

Deep application of nitrogen (N) fertilizer helps to increase crop yield in dryland area, but the effect of depth of N fertilizer on wheat yield in hilly and gully regions of the Loess Plateau under different precipitation types is still unclear. This study used the meteorological data from 1990 to 2020, to explore the effect of N application depth on wheat yield in different precipitation types based on APSIM model and mathematical statistical methods. The correlation coefficient (R²) of the simulated and observed value of wheat yield and biomass was greater than 0.9, the model validity index (M_E) was greater than 0.8, and the normalized root mean square error (NRMSE) was less than 0.2, indicating that the model had good applicability in this region. The NRMSE of simulated and observed soil moisture dynamics during the growth period and soil profile moisture content at the harvest stage of the wheat field were 0.05 ~ 0.07 and 0.13 ~ 0.29, respectively, demonstrating that the model could accurately simulate the wheat field soil moisture changes. The yield potential of deep application of N fertilizer was the highest in wet years, followed by normal years. Compared with drought years, increasing the depth of N application in wet and normal years under the same nitrogen application rate could improve the stability and sustainability of farmland productivity. When the nitrogen application level was 150 kg/hm², increasing the depth of N application in wet and normal years had no obvious effect on the stability of farmland productivity, but it helped to improve the sustainability of farmland productivity. The interaction relationship between N application depth and amount and yield under different precipitation types showed that the relationship between wet years and normal years was better, with R² of 0.76 (P < 0.05) and 0.61 (P < 0.05), respectively. Increasing the depth of N application to 20 ~ 23 cm could obtain the highest potential yield. In a drought year, R² was 0.29 (P > 0.05), increasing the depth of N application had no significant effect on wheat yield. The results of the study are expected to provide theoretical guidance for optimizing fertilization measures at the regional scale for wheat in the hilly and gully regions of the Loess Plateau.