摘要
化肥过量施用导致土壤养分累积引起的氮(N)磷(P)淋失是农业面源污染的重要形式。基于有效提高养殖废弃物的资源化利用率和保护地下水水质等目的,通过田间小区试验研究了有机肥(M)与化肥(F)不同配施比例对100 cm深度稻田土壤N淋失特征的影响。结果表明:在整个晚稻生长期内,渗漏水中不同形态溶解态N浓度的动态变化不尽一致,其中总氮(TN)和铵态氮(NH+4-N)的浓度在每次施肥之后1~3 d出现淋失高峰,最大分别达到1.985、1.165 mg N·L-1,而硝态氮(NO-3-N)浓度的变化比较平缓,无明显峰值。就组成成分而言,NH+4-N为淋失TN的主要成分,平均占54.2%;其次是有机态氮(ON),占45.1%;NO-3-N浓度很低(〈0.2 mg N·L-1),仅占0.7%。随着有机肥比例的增高,晚稻产量表现为显著(P〈0.05)的先增后降变化趋势,与TN及NH+4-N淋失量和淋失率的变化趋势相似,但N的峰值比产量略有滞后。综合考虑施肥的增产作用与土壤N的淋失风险,研究区稻田化肥与有机肥的配比采用7:3较为适当。
Excessive applications of chemical fertilizers cause nitrogen(N)and phosphorus(P)leaching and thus agricultural non-point source pollution. Here, we conducted a field experiment to study the impact of manure(M)and chemical fertilizer(F)combination on soil N leaching at a depth of 100 cm in paddy field in red earth hilly area, Hunan Province of China. The results showed that the peak concentra-tions of total nitrogen(TN)and ammonium nitrogen(NH+4-N)in leachates occurred 1~3 d after fertilizer addition and the maximum values were 1.985 mg N·L-1 and 1.165 mg N·L-1 for TN and NH+4-N, respectively. However, nitrate(NO-3-N)concentrations in the leachates were at a relatively low level(〈0.02 mg N·L-1)and varied little without any obvious peaks. Of TN in the leachates, NH+4-N was the main form (54.2%), followed by organic nitrogen(45.1%)and NO-3-N least(0.7%). The grain yield of late rice increased in treatments with manure ratios of 0 to 30%, but decreased with 30%to 60%of total nitrogen addition. Leaching amounts and rates of TN and NH+4-N showed similar trends during growth of late rice. Taking into consideration of rice yield and leaching risk of soil N, an application ratio of 7:3 chemical to manure fertilizer is recommended in the studied area.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2014年第6期1159-1166,共8页
Journal of Agro-Environment Science
基金
国家支撑计划课题(2012BAD14B17)
国家自然科学基金(41171396)
关键词
亚热带
稻田土壤
有机肥化肥配施
氮素淋失
面源污染
subtropics
paddy soil
manure-fertilizer combined application
nitrogen leaching
non-point source pollution