摘要
土壤氮磷淋失是农业面源污染的一种重要形式。以亚热带稻田为研究对象,采用陶土头定位观测法比较研究了施肥对稻田土壤氮(N)磷(P)淋失特征的影响。2010—2011年连续近2年的试验结果表明,与不施肥对照(CK)相比,施肥会显著增加稻田土壤N、P的淋失。稻田土壤N的淋失形态有显著差异(P<0.05),水稻生长期(4—10月)淹水条件下淋失形态主要为NH4+-N,而闲田期(10—翌年3月)非淹水条件下则主要为NO3--N。这与土壤通气状况的变化有密切关系。研究区10—12月(闲田期)稻田P的淋失明显高于其他时期,是稻田土壤P淋失的主要阶段。控制土壤N、P累积是降低稻田土壤N、P淋失的重要途径。
Nitrogen(N) and phosphorus(P) leaching in soil is regarded as one of the important aspects of agricultural nonpoint source pollution.The characteristics of N and P leaching from a double rice-cropped paddy soil in subtropics with two fertilization treatments(Fert:195 kgN·hm-2 season-1 and 69 kgP·hm-2 season-1,and CK:no fertilizers)were studied using a suction cup sampling method.The field observations were conducted at four soil depths:15 cm,30 cm,60 cm,and 90 cm from soil surface and from April 2010 to November 2011.Our results showed that compared with CK the Fert treatment significantly enhanced the leaching of N and P in paddy soil,in particular during the rice growing season.The leached N was observed significantly different(P<0.05) in N forms at different observation times,i.e.ammonium N dominated during the rice growing season under water-logged condition(April-middle October) and contrarily nitrate N prevailed during the fallow season under drained condition(late October-March).This was expected to be attributed to the alteration of soil aeration.The P leaching risk in the fallow season(October-December) under drained condition was significantly greater than other periods.Therefore,the fallow season was probably the key P leaching period in the paddy soil in this area.We speculated that controlling N and P accumulation in soil and strengthening water management during the fallow season could be the effective approaches to reduce N and P leaching risk of paddy soil.Besides,it was also found that compared with the 0.01 mol·L-1 CaCl2 and Olsen(0.5 mol·L-1 NaHCO3) extraction methods,the Bray-1(0.03 mol·L-1 NH4F + 0.025 mol·L-1 HCl) method performed the best to determine the P leaching risk of paddy soils in this study area.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2013年第5期991-999,共9页
Journal of Agro-Environment Science
基金
国家自然科学基金(41171396)
国家支撑计划课题(2012BAD14B17)
中国科学院创新团队项目(ZCX2-YW-T07)
关键词
亚热带稻田土壤
氮磷淋失
动态特征
陶土头采样法
闲田期淹水条件
paddy soil in subtropics
nitrogen and phosphorus leaching
dynamic characteristics
suction cup sampling method
waterlogged condition during fallow season
