基于生长度日和降水量的韩国饲用玉米产量预测模型构建

Construction of a yield prediction model for whole crop maize on the basis of climatic data in South Korea

本研究基于韩国不同地区的气象数据和饲用全株玉米(Zea mays)产量的历史记录数据,利用一般线性模型进行了饲用全株玉米的干物质产量预测模型的构建。作物产量等相关数据采集自韩国农业协同组合中央会饲料作物研究课题报告,气象数据采集自韩国国家气象厅网站。经过4个步骤的数据整理,最终用于模型构建的数据集包含了22年间(1988-2011年)的775个数据点。以干物质产量为因变量,通过逐步回归分析,两个气象变量被选定为构建产量预测模型的最适气象变量。进一步,通过一般线性模型,构建了包含两个选定的气象变量和以虚拟变量形式考虑进模型的栽培地域变量的韩国饲用全株玉米产量预测模型:DMY=11.298SHAGDD-3.651SHP+1 089.870+Location。其中,DMY为饲用全株玉米的干物质产量,SHAGDD为播种到收获累积生长度日,SHP为播种到收获累积降水量。通过残差分析和10折交叉验证对所构建的模型进行了检验。根据此产量预测模型,可以发现作物生长期间的温度和降水量对饲用全株玉米的干物质产量有着显著的影响。因此,确定合理的播种和收获时间以使作物获得充分的生长对确保合理的作物产量有着重要意义。此外,基于韩国夏季降水相对集中的气象条件,选择拥有较好排水性的土地和较强耐涝性的作物品种,也是确保饲用全株玉米产量的重要因素。

The objective of this study was to construct a dry matter yield(DMY)prediction model for whole crop maize(WCM,Zea mays)on the basis of climatic data by location in South Korea.The forage crop and climatic data were collected from the reports of national research projects on forage crops and the website of Korea Meteorological Administration,respectively.The data set(n=775)of 22 years(1988-2011)was used to construct the model after a four-step data preparation.Two optimal climatic variables were selected through stepwise multiple regression analysis,with DMY as the dependent variable.Subsequently,using a general linear model,the final model,whichincluded the two climatic variables and cultivated location(in the form of a dummy variable),was constructed as follows:DMY=11.298SHAGDD-3.651SHP+1 089.870+Location,where SHAGDD refers to seeding-harvest accumulated growing degree days and SHP,seeding-harvest precipitation.The homoscedasticity and assumption that the mean of the residualsequal to zero was satisfied and the reliability of the model were good,since most scatters of the predicted DMY values fell within the 95%confidence interval.The model was tested using residual diagnostics and 10-fold cross-validation.The results showed that the variables related to temperature and precipitation had significant effects on the WCM yield.Therefore,accurate determination of sowing and harvest dates is important to ensure that the crops grow under appropriate accumulative temperature conditions.Furthermore,land with good drainage and cultivars with strong tolerance to water logging are necessary for the cultivation of WCM in South Korea because of excessive precipitation during the growing season.