CSM-CERES-Rice model to determine management strategies for lowland rice production

The cropping system model, namely, the crop environment resource synthesis-rice (CSM-CERES-Rice) model, is a decision supporting tool for the design of crop management. This study aimed to determine management practices for increasing rice (Oryza sativa L.) production in Laos by using the CSM-CERES-Rice model. The model was evaluated with data sets from the TDK8 and TDK11 cultivars in farmers’ fields in the Vientiane plain in 2012. Anthesis and harvesting dates, growth and yield for various management scenario combinations (eight transplanting dates × two levels of plant densities × three rates of nitrogen (N) fertilizer application) for both cultivars were simulated by the model from 1980 to 2012. The model evaluation results showed strong agreement between simulated and observed data for days to harvest with a difference within four days. The model provided acceptable accuracy for grain yields with normalized root mean square error values ranging between 1 and 16 %. The results from the model application indicated that TDK8 and TDK11 produced similar yields. Transplanting TDK8 with two plant densities produced similar yields. The highest yield for both cultivars was achieved on the transplanting date of 15 Jan. N-fertilizer application at 60 and 120 kg N ha−1 was able to increase yield for TDK8 by 50 and 87 %, respectively, and for TDK11 by 54 and 70 %, respectively. Rice transplanted on 15 Jan with 5 seedlings hill−1 and N-fertilizer at 120 kg N ha−1 had the highest average yield for both cultivars with 6,460 and 6,351 kg ha−1 for TDK8 and TDK11, respectively. The CSM-CERES-Rice model is an alternative tool in determining crop management practices for rice production.

作物系统模型（cropping system model），即CSM-CERES-Rice模型，是一款用于作物管理方案设计的决策支持工具。本研究旨在借助CSM-CERES-Rice模型，探寻老挝境内提升水稻（Oryza sativa L.）产量的田间管理方案。本研究于2012年利用万象平原农户田块中TDK8与TDK11两个水稻品种的实测数据集，对该模型进行了评估验证。该模型于1980年至2012年间，针对两个品种的多种管理情景组合（8个移栽期×2个种植密度水平×3个氮肥施用量梯度）下的开花期、收获期、生长状况及籽粒产量进行了模拟。模型评估结果显示，模拟收获天数与实测数据吻合度极高，二者差值不超过4天。该模型对稻谷产量的模拟精度处于可接受范围，归一化均方根误差值介于1%至16%之间。模型应用结果表明，TDK8与TDK11两个品种的产量表现相近。采用两种种植密度移栽TDK8，其产量水平无显著差异。两个品种均在1月15日移栽时达到最高产量。当氮肥施用量分别为60 kg·ha⁻¹与120 kg·ha⁻¹时，TDK8的产量可分别提升50%与87%，TDK11的产量则可分别提升54%与70%。在1月15日移栽、每穴5株苗且氮肥施用量为120 kg·ha⁻¹的情景下，两个品种均达到最高平均产量，TDK8与TDK11的产量分别为6460 kg·ha⁻¹与6351 kg·ha⁻¹。CSM-CERES-Rice模型可作为水稻生产田间管理方案制定的备选工具。