施氮对高肥力稻田氮肥利用率及土壤-水体铵氮损失的影响  

Effect of Nitrogen Applications on Nitrogen Use Efficiency and NH_4^+-N Loss Status in Soil-Water System of High Quality Paddy Soil

作　　者：郭彬[1] 丁能飞[1] 林义成[1] 刘琛[1] 李华[1] 李凝玉[1] 傅庆林[1] 

机构地区：[1]浙江省农业科学院,环境资源与土壤肥料研究所,浙江杭州310021

出　　处：《水土保持学报》2010年第5期180-183,190,共5页Journal of Soil and Water Conservation

基　　金：国家“十一五”科技支撑计划课题(2006BAD05B08);浙江省重大科技公关项目(2005C12025);公益性行业(农业)科研专项经费项目(200903001-1-7)

摘　　要：研究稻田不同施氮量下的农学效率和环境效应,对水稻高效优质环境保护型生产和合理施肥具有重要意义。在平湖稻区研究了不同施氮下水稻边际利润、最佳经济施肥量以及不同时期氮素利用率、土壤固定态铵、碱解氮及田面水铵氮浓度的动态变化。结果表明,当地水稻最佳经济施肥量为235kg N/hm2;施氮225kg/hm2时当季氮肥利用率仅为31.2%。土壤固定态铵以及碱解氮含量均在水稻生长时期内逐渐下降,但随施氮量的增加而增加。低氮处理促使土壤固定态铵含量有较大增幅,而高氮处理则使土壤碱解氮含量有较大增幅。在水稻不同生长时期的施肥后一个星期内,高于225kg N/hm2处理田面水NH4+-N急剧上升而后急剧下降;而75,150kg N/hm2处理田面水NH4+-N一直低于2mg/L。可见,浙北地区氮肥施用量保持在225kg/hm2为宜,过量施氮(超过225kg/hm2)将超过水稻的正常生长需求,造成土壤固铵量饱和,引起土壤碱解氮含量急剧上升,并导致田面水NH4+-N含量急剧上升。Field experiment was conducted to investigate rice yield,optimal N-fertilizer requirement,and nitrogen use efficiency,soil-fixed ammonium content,available nitrogen content of soil,NH4^＋-N content in surface water during rice-growth periods.Results showed that the optimal N-fertilizer requirement was 235 kg N/hm^2.Nitrogen use efficiency was decreased with increase of N-fertilizer amendments,and the nitrogen use efficiency was 31.2% in 225 kg N/hm^2 treatment.Both soil-fixed ammonium and available nitrogen content of soil were decreased during rice-growth periods,but increased with increasing N-fertilizer incorporations.Higher increasing effect on soil-fixed ammonium content in 75-225 kg N/hm^2 treatment was observed compared to 300-450 kg N/hm^2 treatments;while lower increasing effect on available nitrogen content of soil in 75-225 kg N/hm^2 treatment was found compared to 300-450 kg N/hm^2 treatments.NH4^＋-N contents in surface water in higher than 150 kg N/hm^2 treatments were increased sharply after 2-3 days of incorporation,and then were dropped lower than 2 mg/L after 4-7 days of incorporation.While NH4^＋-N contents in surface water in 75,150 kg N/hm^2 treatments were not changed during the N applications and rice-growth periods.Totally,the N application amount should be recommended in the range of 150-225 kg N/hm^2.Excessive N application （higher than 225 kg/hm^2） saturated soil-fixed ammonium content,increased available nitrogen content of soil sharply and finally caused rapid change in NH4^＋-N contents in surface water.

关 键 词：氮肥利用率 土壤固定态铵 土壤碱解氮 田面水铵氮 

分 类 号：S143.1[农业科学—肥料学] S158.3[农业科学—农业基础科学]