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采用田间小区试验,研究了太湖地区大棚蔬菜不同施N量对土壤NO3--N累积及其土壤电导率、pH和蔬菜产量品质的影响。结果表明:土壤NO3--N的累积与施N量呈正比,种植两季蔬菜后,农民习惯施N下的土壤NO3--N从35 mg/kg上升到221.35 mg/kg;土壤电导率、pH与NO3--N含量显著相关,其中电导率与NO3--N的关系更为密切,相关系数达到0.832。NO3--N的累积导致蔬菜的产量与品质下降,与莴苣、芹菜施N量分别为312、384 kg/hm2的处理相比,农民习惯施N处理下的莴苣和芹菜产量分别下降了11.8%和33.9%,Vc含量下降了17%和36.6%,而硝酸盐含量增加了22.3%和32%,农民习惯施N处理下的两季蔬菜硝酸盐含量均达到三级污染,可危害人体健康。
Field experiments were conducted to study the effects of N application rate on soil NO3 - N accumulation, soil conductivity, pH and yield and quality of vegetables in greenhouse in Taihu Lake. The results showed that the accumulation of NO3 - N in the soil was proportional to the N application rate. After two seasons of planting vegetables, the NO3 - N in the soil increased from 35 mg / kg to 221.35 mg / kg under the habit of N application. The soil conductivity, pH and NO3 - N content were significantly correlated, and the conductivity was more closely related to NO3 - N, the correlation coefficient reached 0.832. The accumulation of NO3 - N led to the decrease of yield and quality of vegetables. Compared with the treatments of lettuce and celery with 312,384 kg / hm2 N, the yield of lettuce and celery decreased by 11.8% And 33.9%, Vc content decreased by 17% and 36.6%, while the nitrate content increased by 22.3% and 32%. The nitrate content of vegetables in two seasons of peasants accustomed to N treatment all reached tertiary pollution, which could endanger human health.