摘要
通过田间定位试验与土壤渗漏仪 (Lysimeter)模拟试验 ,研究太湖地区稻麦生产中氮肥过量施用带来氮肥利用率低与环境污染问题 ,探讨本区稻麦高产与减少氮肥淋洗的适宜氮肥用量。初步试验结果表明 ,氮肥适宜用量随着稻麦产量的提高而增加 ,本区两种主要土壤水稻、小麦高产的氮肥适宜用量(以N计 )分别为 2 2 5～ 2 70kghm- 2 与 1 80～ 2 2 5kghm- 2 ;适宜的氮肥用量使单位面积的有效穗数和每穗的结实颖花数均高 ,因而产量高。氮素的淋洗以NO- 3 N为主 ,主要发生在麦季与泡田插秧初期 ,其含量随着施氮量的增加而增加 ,每hm2 施N 2 2 5kg的模拟试验 ,麦季渗漏液的NO- 3 N浓度在 5 4～ 2 1 3mgL- 1,有60 %的样次超过污染标准 (NO- 3 N 1 0mgL- 1) ;田间试验 ,麦季施N量在 2 70～ 31 5kghm- 2 范围内 ,地下水NO- 3 N浓度在 1 9～ 1 1 0mgL- 1,有 2 0 %的样次接近 ,1 0 %的样次超过污染标准。长期NO- 3 N渗漏累积 ,势必对地下水构成潜在威胁。
To aim the problem of nitrogen fertilizer overused to cause lower efficiency of fertilizer-N utilization and environment pollution, the field and lysimeter experiments under different amount of fertilizer-N applied were conducted in the Taihu lake area to seek the optimum nitrogen rate for a high productive rice-wheat system and reducing nitrate leaching. The preliminary results showed fertilizer-N rate used increased with yield of rice & wheat. Optimum rates of fertilizer-N ranged from 225 to 270 and 180 to 225 N kg hm -2 for rice and wheat in the two main paddy soils, respectively. With both high percentage of earbearing tiller and setting percentage, yields of rice & wheat were higher at optimum rate of fertilizer-N used than at other treatments. Nitrogen was leached away from field mainly in the form of NO- 3-N, not NH+ 4-N, and it occurred in the season of growing wheat and the early stage of rice pouding and transplanting. Nitrate-N concentrations in the leachate increased gradually with the increasing of fertilizer N applications. Which in the lysimeter leachate ranged from 5.4 to 21.3 mg L -1 from the field receiving 225 kg hm -2, with 60% leachate being over the standard of 10 mg L -1 NO- 3-N standard and in groundwater ranged from 1.9 to 11.0 mg L -1 from the fields receiving 270 to 315 N kg hm -2,with 20% samples being nearly and 10% over the standard, respectively. Although NO- 3-N levels in groundwater from fertilized fields are usually well below the standard, cumulating of high NO- 3-N leachate will be a potential risk of water contamination in Taihu Lake area.
出处
《土壤学报》
CAS
CSCD
北大核心
2003年第3期426-432,共7页
Acta Pedologica Sinica
基金
国家重点基础研究发展规划项目 (G1 9990 1 1 80 2 )
中国科学院区域开发前期研究项目 (区域IV - 990 5 )资助
