沈阳自然气候条件下拔节和抽雄期水分胁迫玉米的生长模拟研究

Simulation of Maize Growth under Water Stress during Jointing and Tasseling in Shenyang Natural Climate Condition

为了探讨DSSAT软件在模拟玉米生长过程中的适用性,在田间试验的基础上,利用玉米生长模型DSSAT-CERES-Maize模拟了水分胁迫条件下辽宁地区玉米的生长发育和产量形成过程,并确定了参数估计和模型验证的最优方案。试验将玉米整个生育期划分为苗期、拔节、抽雄、灌浆和成熟5个主要生长阶段,选择其中的拔节期(J1、J2、JCK)和抽雄期(T1、T2、TCK)进行水分胁迫控制,分别采用田间持水量的60%~65%(轻度水分胁迫)、45%~50%(中度水分胁迫)和30%~35%(重度水分胁迫)3个水分胁迫水平,共6个处理,每个处理3次重复,在遮雨棚内随机排列。利用DSSAT-GLUE参数估计模块得到不同的参数估计结果,通过对比分析玉米物候期、单粒质量、产量、叶面积指数(LAI)、以及土壤水分的模拟值和实测值之间的差异,以确定该模型模拟辽宁地区玉米生长发育过程的精度。结果表明:遗传参数P2的估计值具有较大的变异性,变异系数为59.03%。在模型应用过程中应选用轻度水分胁迫以及在生育后期受到水分胁迫影响的观测数据进行遗传参数估计,可以提高模型的模拟精度,误差可以减小到6.7%~9.9%。在对作物LAI和水分动态模拟结果的分析中可以看出,同一生育期水分胁迫程度越低模型模拟精度越高;同一水分胁迫条件下抽雄期处理模拟精度高于拔节期处理。从留一交叉验证法的分析结果可以看出,总体模拟误差在12%~15%之间。说明DSSAT-CERES-Maize模型在模拟辽宁地区不同水分胁迫条件下玉米生长发育和产量形成过程方面具有较好的适用性。

In order to study the suitability of software DSSAT in the use of simulating maize growth,we applied DSSAT-CERES-Maize to simulate the growth and yield of maize under water stress in Liaoning Province in field test.The optimal plan was also determined for the estimation of genetic parameters and model verification.Field experiments were conducted in a rainproof shelter under water stress at different growth stages of maize.The whole growth season of maize was divided into5stages,seedling,jointing,tasseling,filling and mature.Water stress occurred at jointing(J1,J2,JCK)and tasseling(T1,T2,TCK)stages.Three water stress levels were applied,including mild water stress(60%-65%of field capacity),moderate water stress(45%-50%of field capacity)and severe water stress(30%-35%of field capacity).There were6treatments with3replications.The experimental data were used for model calibration and verification.The DSSAT-GLUE,a program package for parameter estimation in DSSAT,was used to estimate the relevant genetic coefficients.Then the results were compared for the discrepancies between corresponding simulated and observed values of phenological phase,grain weight,yield,leaf area index(LAI),and soil moisture so as to determine the accuracy of DSSAT-CERES-Maize Model in simulating the agro-ecological processes of maize farming system in Liaoning Province.The results showed that the genetic coefficient of P2varied remarkably under different levels of water stress with a variation coefficient of59.03%.In order to improve model accuracy,the observed data of the treatments under mild water stress and water stress at late growth stage should be chosen for genetic parameter estimation,and the error could be reduced to6.7%-9.9%.The simulation results of LAI and soil moisture dynamics showed that the treatment with mild water stress achieved the highest simulation accuracy among all treatments at the same growing stage.For the same degree of water stress,the simulation accuracy at tasseling stage was higher than that at the jointing stage.The results of leave-one-out cross validation showed that the overall error was about12%-15%for DSSAT-CERES-Maize Model in simulating maize growth and yield under different levels of water stress designed in this study.It was concluded that DSSAT-CERES-Maize Model is very suitable in simulating maize growth in Liaoning Province.