【摘要】 我国农业中化肥施用过多而利用率极低 ,过量N、P养分由农田向水系的迁移损失是农业非点源污染的重要问题 .本研究选择太湖地区高产水稻土 (乌栅土 ) ,进行了不同施肥量及其养分配比的肥料试验 .结果表明 ,供试土壤的基础肥力相当于 6 75t/hm2 产量 ,总施肥量 (N +P)为 3 0 0kg/hm2 时达到土壤的极点产量 (9 79t/hm2 ) ;但发现施肥量 (N +P) 2 4 0kg/hm2 时产量仍可达 9 69t/hm2 ,此时养分的产量效应最大 .为此 ,笔者提出一种经济极点施肥模式 (化肥N +P 2 4 0kg/hm2 ,N∶P∶K比为 3∶2∶0或 1∶1∶0 ) ,可以减少 3 0 %的N、P施用量 .这可以进一步发展为环境安全的减肥 轮肥新技术 ,从而有利于控制N、P的农业非点源污染更多还原

【Abstract】 Excess application with the poor efficiency of fertilizers is one of the major problems confronting the sustainable agricultural development. Whereas, loss of N and P nutrients from farmlands to surface waters is considered as one of the major sources inducing eutrophication. In order to work out a minimum fertilizer application rate for both keeping conventional yield and reducing nutrient loading of non point source pollution, an experiment of formulated fertilization scheme on rice at different rates and nutrient ratios by incorporating the soil supply potential was conducted in a paddy soil Wunitu in Kunshan City, Suzhou. The soil nutrient can supply a yield at 6 75 t/hm 2 at least for one cropping season. Among the fertilization treatments, a maximum yield of 9 79 t/hm 2 was obtained at fertilization (N+P) rate of 300kg/hm 2kg N and P at a ratio of N to P being 3∶2 or 1∶1. However, with much lower fertilization (N+P) rate at 240kg/hm 2 with the same ratio a high yield of 9 69t/hm 2 was reached . The fertilizer efficiency of the later was 3 times as that of the former rate. Thus, a economical and environmentally sound mode of fertilization in such paddy soils as total N and P 240kg/ hm 2, with N∶ P ∶Kratio being 3∶2∶0 or 1∶1∶0 was developed. Further study would be directed to a innovation of combination of reducing fertilization rate with rotated fertilization for alternative crops.更多还原