利用APSIM模型分析不同播期和耕作方式对旱地小麦籽粒干物质积累的影响

黄土丘陵区旱地小麦籽粒干物质积累的准确模拟可为调控小麦生产提供重要的技术支持。本研究利用甘肃省定西市安定区1971—2017年的气象资料和甘肃省定西市安定区凤翔镇安家沟村2016—2017年的大田试验数据,基于APSIM模型对旱地小麦籽粒干物质积累与分配进行模拟,并在模型验证的基础上,定量分析了播期和耕作方式对小麦籽粒干物质积累的影响。结果表明: 3个播期(早播、正常播、晚播)和4种耕作方式(传统耕作、传统耕作+覆盖、免耕、免耕+覆盖)下,籽粒干物质模拟值与实测值间的均方根误差(RMSE)为57.5～143.1 kg·hm^-2,归一化均方根误差(NRMSE)为1.4%～9.9%,模型模拟精度较高。不同播期下,耕作方式对籽粒干物质积累的促进效果排序均表现为: 免耕+覆盖>传统耕作+覆盖>免耕>传统耕作,免耕+覆盖最有利于小麦籽粒干物质积累,而免耕与传统耕作差异不显著。不同耕作方式下,小麦干物质积累过程均表现为早播好于正常播和晚播,晚播对干物质积累的影响较大,积累过程最不理想。

Evaluating the effects of different sowing dates and tillage methods on dry-land wheat grain dry matter accumulation based on the APSIM model

Accurate simulation of dry matter accumulation in wheat grains can provide important technical support for regulating wheat production in hilly areas of Loess Plateau. Using the APSIM model, we analyzed dryland wheat grain dry matter accumulation and distribution using the meteorological data from 1971 to 2017 in Anding District, and the field test data from 2016 to 2017 in Anjiagou Village, Fengxiang Town, Anding District, Dingxi City, Gansu Province. Furthermore, the influence of sowing date and tillage method on dry matter accumulation of wheat grain was quantitatively analyzed on the basis of model validation. The results showed that the root mean square error(RMSE) between the simulated and measured values of grain dry matter was 57.5-143.1 kg·hm^-2 and the normalized root mean square error(NRMSE) was 1.4%-9.9% under the three sowing dates and four tillage methods, respectively. The precision of the APSIM model was satisfactory. Under different sowing dates, the order for beneficial degree of tillage treatment to dry matter accumulation in wheat grains was no tillage with straw cover > conventional tillage with straw cover > no tillage > conventional tillage. The treatment of no tillage with straw covered was the most favora-ble to dry matter accumulation in wheat grains, with no significant difference between no tillage and conventional tillage treatments. Under different farming methods, early sowing was better than normal sowing and late sowing for the dry matter accumulation process of wheat. Late sowing had stronger impacts on dry matter accumulation, with the least ideal accumulation process.