Study on Yield Potential and Water Requirement of Aerobic Rice in Beijing Area Based on ORYZA2000 Model

摘要

With the decreasing water supply in agriculture, water consumption in rice production has to be reduced and water utilization efficiency increased. Irrigated aerobic rice is a new system being developed in lowland areas with water shortage and favorable upland areas with access to supplementary irrigation. Investigations are made to study this new aerobic rice system. In this study, we tried to make an elementary study on yield potential and water requirement of aerobic rice in Beijing area using ORYZA2000 model. ORYZA2000 model for aerobic rice was evaluated through field experiments conducted from 2002 to 2004 at the Changping ExperimentStation (40°02′ N, 116°10′ E; altitude of 43 m) of China Agricultural University,Beijing. The model adequately simulated water requirement, crop growth and grain yield.After validation of the model, the yield potential and water requirement of aerobic rice in Beijing region were obtained by using this model as well as historical weather data from 1971 to 2000. Simulation results showed that average yield potential for 30 years was 8 573 kg ha-1,ranging from 6 747 to 11 278 kg ha-1. Inter-annual variation coefficient of yield potential was 16.3%, while average rainfed yield was only 4 048 kg ha-1 , varying from a very low level of 223 kg ha-1 , to even 8 018 kg ha-1. So, the variation among years was very large with a coefficient of 51.1%. The gap between rainfed yield and yield potential indicated that yield of aerobic rice in Beijing region could be increased to some extent. Water requirement for whole growing season was 713 mm with 8.5% variance calculated from ORYZA2000 model. Most water was consumed at the stage from emergence to panicle initiation which was the longest duration. Mean water requirement for the whole season was 5.3 mm d-1, while the highest value of 5.5 mm d-1 occurred from panicle initiation to flowering. Total precipitation during the whole growing season of aerobic rice in Beijing can not meet its water requirement, and there were 15 years from 1971 to 2000 in which water shortage was higher than 250 mm.