摘要
采用田间小区试验,研究了太湖地区设施菜地一年三季作物(番茄-莴苣-芹菜)氮素淋失特征。结果表明:太湖地区设施菜地氮淋失以NO3--N为主,氮素淋洗量受施氮量的直接影响,以农民习惯施氮量(N5)处理下的淋洗总量最高,全年TN淋失总量高达193.6 kg.hm-2。在N5基础上减施N 40%(N3)可分别减少番茄、莴苣和芹菜季TN淋洗损失40.4%、49.2%和57.5%,同时可分别增产15.1%、39.0%和27.8%。设施菜地氮素淋洗高峰发生在揭棚期(7—11月),其中包括揭棚休闲期和莴苣生长前期。揭棚期淋洗液TN平均浓度为51.1 mg.L-1,是盖棚期TN浓度的1.7倍;TN淋洗量为129.2 kg.hm-2,约占全年总氮淋洗量的66.7%。
A field experiment was conducted to evaluate the effect of nitrogen（N） fertilizer application rates on N leaching loss from protected vegetable soil in Tai Lake region,China.Five N treatments,including N1（no fertilizer）,N5（conventional N application rate at 1 560 kg·hm-2·a-1）,N2（at 40% of N5 the N rate）,N3（at 60% of the N5 N rate）,and N4（at 75% of the N5 N rate）,were applied to a tomato,lettuce and celery rotation,a typical protected vegetable cropping system in the region.It was found that the main form of the N leached was nitrate-N,and the leaching loss increased with the N rates.The highest annual total N leaching loss at 193.6 kg·hm-2 ocurred in the N5 treatment.Compared with the N5 treatment,the N leaching loss in the N3 treatment reduced by 40%,49% and 58%,and yield increased by 15%,39% and 28%,in the tomato,lettuce and celery season,respectively.The leaching loss of N peaked in the open period,from July to November when the plastic cover was removed and the soil was subject to rainfall,including fallow period and early stage of lettuce.The average total N concentration in the leachate was 51.1 mg·L-1 during the open period,which was 1.7 times greater than that in the covered period.The total N leaching loss was 129.2 kg·hm-2 in the open period,which accounted for 67% of the total annual loss.Our results demonstrate that the technique of reducing N fertilizer application rate can greatly minimize the environmental risk of N loss from protected vegetable field without any negative effect on vegetable yields.The fallow period should be the most critical period for controlling the total N leaching loss.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2012年第4期706-712,共7页
Journal of Agro-Environment Science
基金
公益性行业(农业)科研专项(201003014-1)
国家科技重大专项"水体污染控制与治理"湖泊主题太湖项目课题:闸控入湖河流直湖港及小流域污染控制技术及工程示范(2008ZX07101-005)
关键词
太湖地区
设施菜地
氮
淋失
Tai Lake region
protected vegetable
nitrogen
leaching loss
