秸秆覆盖量和施氮量对陇中春小麦的产量效应模拟

Simulation of straw mulching quantity and nitrogen on spring wheat yield effects in dryland of central Gansu Province

为量化分析秸秆覆盖量和施氮量对旱地春小麦的产量效应和协同作用,在APSIM模型中,设置秸秆覆盖量和施氮量2因素5个变化梯度,组合交叉设计25个处理,利用模型模拟25个处理的春小麦产量;于2016—2018年在甘肃省定西市安定区开展小麦大田试验,得到早播(ESW)、正常播(NSW)、晚播(LSW)春小麦产量的实测值,利用APSIM模型模拟2016—2018年春小麦的产量,将模拟值与实测值进行对比,对模型的适用性和模拟精度进行分析;对春小麦产量与秸秆覆盖量、施氮量的耦合关系进行二次多项回归和通径分析,利用Matlab计算春小麦的最大产量及对应的秸秆覆盖量和施氮量。结果表明:不同处理下产量的模拟值与实测值均位于15%置信带内,模型模拟精度较高,归一化均方根误差值为4.64%~12.22%,表明该模型在研究区具有良好的适用性;秸秆覆盖量和施氮量的增长对春小麦的产量效应为正效应,相应关系表现为开口向下的二次抛物线变化关系;ESW、NSW和LSW模拟情景下,春小麦最大产量分别为3548.64、3149.59、2507.58 kg/hm^(2);ESW模式下,最佳秸秆覆盖量和施氮量分别为7062.04、194.91 kg/hm^(2);NSW模式下,最佳秸秆覆盖量和施氮量分别为8211.31、218.81 kg/hm^(2);LSW模式下,最佳秸秆覆盖量和施氮量分别为6215.15、162.01 kg/hm^(2)。

This study aimed to quantitatively analyze the yield effect and synergistic effect of straw mulch and nitrogen on spring wheat in dry land.By use of the APSIM model,the crop yield of spring wheat were set 25 treatments were simulated by using the model with 5 gradients over the two variables,straw cover and nitrogen application.The wheat field experiment was performed in Anding District,Dingxi City,Gansu Province from 2016 to 2018,and the measured values of spring wheat yield were collected in the three sowing periods(ESW,NSW and LSW).APSIM model was used to simulate the simulated values of spring wheat from 2016 to 2018,and the simulated values were compared with the measured values to analyze the applicability and simulation accuracy of the model.The coupling relationship between spring wheat yield,straw mulch amount and nitrogen application amount was analyzed by quadratic multinomial regression and path analysis,and the maximum spring wheat yield and the corresponding straw mulch amount and nitrogen application amount were calculated by Matlab.The results showed that both the simulated and measured yields under different treatments were within the 15%confidence band,and the simulation accuracy of the model was high,with the normalized root mean square error(RMSE)ranging from 4.64%to 12.22%,indicating that the model had good applicability in the study area.The increase of straw cover amount and nitrogen application amount had a positive effect on spring wheat yield,which showed a quadratic parabolic relationship of opening downward.Under ESW,NSW and LSW simulation,the maximum yield of spring wheat was 3548.64,3149.59 and 2507.58 kg/hm^(2),respectively.The optimal combinations of straw mulch and nitrogen application were 7062.04,194.91 kg/hm^(2)and 8211.31,218.81 kg/hm^(2)and 6215.15,162.01 kg/hm^(2),respectively.