FACE水稻氮素动态的模拟研究

Simulation on Nitrogen Dynamic in FACE Rice

为了明确开放式空气CO2浓度增高(FACE)对水稻氮素动态的影响,借助目前我国惟一的FACE技术平台,以武香粳14为供试品种,设置不同施N量处理,研究了大气CO2浓度比对照高200μmol.mL-1的FACE处理对水稻N素吸收利用动态的影响。结果表明,FACE处理使水稻各生育期N素累积量增加,而使含N率下降;增施N肥使FACE及CK条件下的N素累积量均有不同程度的增加。在此基础上建立了相应的模拟模型,模型以时间为驱动因子,描述了水稻N素累积量及含N率随移栽天数的动态变化过程,对CO2浓度增加及常规条件下水稻N素的动态变化均有很好的拟合性。通过不同年份试验数据对模型的检验,结果表明模型的预测性能好,具有很好的适用性。

With the FACE technical platform, we conducted a FACE experiment at Anzhen, Wuxi, Jiangsu Province in 2001-2003, using a Japonica cuhivar Wuxiangjing 14. The target CO2 concentration of the FACE plots was 200 μmol· mL^-1 above that in the ambient air, and three levels of N were supplied： LN（150 kg· hm^-2）, MN（250 kg· hm^-2） and HN（350 kg·hm^-2）. The effect of FACE treatment on nitrogen dynamic in rice was studied and the results indicated that nitrogen accumulation in rice plant increased but nitrogen content decreased at different growth stages under FACE treatment. Nitrogen accumulation increased with the N rates. The model of nitrogen accumulation was described by logistic equation and the exponential and quadratic functions were used to describe CO2 concentration and N effect respectively. The nitrogen content was defined as the proportion of nitrogen accumulation to that of shoot mass. The models were described with days after transplanting, and the nitrogen dynamics were fitted well both under FACE and normal conditions. Through testing with different experimental data, the models were not only accurate but also applicable.