浙江水稻氮肥优化的决策支持系统ONIR

在大量田间试验的基础上,建立了浙江水稻氮肥优化决策支持系统ONIR(optimazation of nitrogen to irrigated rice).该系统是利用NuDSS(nutrient decision support system)与独创的NSAM(N splitting application model)有机结合而成的.氮肥分次施用模型(NSAM)是根据水稻生长发育规律和养分平衡供应原理建立的,目的是确定各生育期的氮肥施用量,也就是氮肥的分次施用量.系统验证结果表明,模拟值与实测值均落在直观图1∶1线附近,线性回归t 检验平均＞0.05,斜率α在0.847 ～ 1.034 之间,确定系数R2在0.85 ～ 0.99之间,均方差误差为1 ～ 110 kg/hm2,规范均方根为 9% ～ 24%.在浙江水稻区,当目标产量为7.3 t/hm2(晚稻)和8.3 t/hm2(中稻)时,利用ONIR推荐的最佳氮肥用量分别为120 kg/hm2和150 kg/hm2;基肥、分蘖前期、幼穗分化期和抽穗期施肥的分配比例:晚稻为0.4∶0.2∶0.4∶0 或0.4∶0.2∶0.2∶0.2,中稻为0.4∶0.2∶0.4∶0 或者0.4∶0.2∶0.2∶0.2.

ONIR-A Decision Support System for Optimization of Nitrogen to Irrigated Rice in Zhejiang Province, China

Based on the results of field fertilization experiments of rice conducted in Zhejiang Province, China, a decision support system for Optimization of Nitrogen to Irrigated Rice (ONIR) was developed, calibrated and validated. The system included NuDSS (the nutrient decision support system) and N Splitting Application Model (NSAM). NuDSS was a recently developed software for irrigated rice based on QUEFTS and SSNM, which was used to optimize nutrient management for rice varieties. According to NuDSS, the optimal fertilizer N requirement for the target yields could be calculated. We developed NSAM that could make sure N splitting application which based on the rhythm of growth and development of rice and nutrient balance. The results showed that the observed and simulated values of NA and DMA at different stages and grain yields at different N treatments fell near the 1:1 lines in the main. Values of α,R~2 were in the range of 0.847～1.034 and 0.85～0.99, respectively. All P(t~*) were larger than 0.05, yields absolute RMSE varied from 1 to 110 kg/hm~2 and normalized RMSE varied from 9% - 24%. The attainable target yields were set to 70 to 75 percents of their potential yields. The attainable targets of late rice and middle rice in Zhejiang were 7.3 and 8.3 t/hm~2 according to the potential yield simulated with WOFOST. On reasonable yield targets of late rice and middle rice in Zhejiang, the optimal fertilizer N requirement recommended by ONIR was about 120 kg/hm~2 with splitting fractions of 0.4:0.2:0.4:0 or 0.4:0.2:0.2:0.2 and 150 kg/hm~2 with splitting fractions of 0.4:0.2:0.2:0 or 0.4:0.2:0.2:0.2 as basal, at early tillering, panicle initiation and flowering stages, respectively. N application was only about 70% of the fertilizer N application under current farmers' practice. N input could be reduced in some degree without yield loss if rice N management practice were improved in Jinhua of Zhejiang Province.