基于DNDC模型的东北半湿润区膜下滴灌玉米施肥制度优化

东北半湿润地区玉米生育期内的降雨量通常较多,给田间试验开展施肥制度优化研究带来一定困难。本文结合田间试验结果,利用DNDC模型优化了玉米膜下滴灌施氮次数和施氮比例。其方法是在对DNDC模型参数进行敏感性分析的基础上,分别利用2012和2011年东北膜下滴灌玉米田间试验数据对DNDC模型中作物参数进行率定和验证,最后利用验证后的模型优化出适宜的施氮次数和施氮比例。研究结果表明,对玉米吸氮量和产量影响较大的参数为大气CO_2浓度、作物需水量、降雨量和籽粒C/N等;验证后的模型能较精确模拟玉米的产量和吸氮量,而对玉米的生长动态模拟精确度相对较差;当土壤初始无机氮含量在60 mg/kg时,东北半湿润区膜下滴灌玉米的适宜施氮量为150~200 kg/hm~2,且在玉米抽穗期和灌浆期以1:3的比例施入氮肥可使氮肥的淋失量减少,而产量也可保持在较高水平。

Optimization of fertilizing schedule for maize with mulched drip irrigation in sub-humid region of Northeast China DNDC model

The high rainfall during the growing season of maize brought some difficulties for field experiment aiming at attaining optimal fertilization scheduling in northeast sub-humid area. In this study, DNDC model was used to optimize fertilizing schedule for maize in sub-humid Northeast China, and a 2-year field experiment including maize growth and yield data measured under mulched drip irrigation in Northeastern China was used to serve the model calibration and verification. The sensitivity analysis of the modelparameters was carried out. Furthermore, the validated model was used to optimize fertilizing frequency and fertilizing ratio of maize under different fertigation scenarios. The simulated results showed that atmospheric CO₂ concentration, crop water requirement, rainfall, and the Grain C:N had a greater effect on yield and nitrogen uptake of maize. The DNDC model performed well in predicting yield and nitrogen uptake of maize, whereas the dynamics of corn growth was not adequately preserved. Besides, for a higher initial nitrogen content level with about 60 mg/kg, the nitrogen amount of 150~200 kg N/hm² and the ratio of 1:3 during heading stage and filling stage were recommended for obtaining higher crop yield and less nitrogen leaching in sub-humid region of northeast China.