关键词: 农田, 蔬菜, 地下水, 土壤, 硝酸盐

Abstract:

【Objective】 The aim of this study was to determine the nitrate pollution status of soil, groundwater and vegetables in three typical farmlands (cropland, vegetable field and orchard) in Beijing region. 【Method】 Based on the investigation method, the samples of the soil, groundwater and vegetables from different farmlands were collected and measured. In addition, attributes of all samples were recorded for dataset analyzing. 【Result】 The results showed that nitrate was substantially accumulated in soil profiles, while the soil nitrate concentrations of vegetable field and orchard were higher than those of cropland,which nitrate content in 0-30 cm soil of vegetable field and orchard were 3.8 and 1.2 times of the mean value of cropland respectively. Nitrate content of groundwater in vegetable field was 13.8 mg?kg-1 (with the over-standard ratio 44.8%), which was 2.8 folds of that in cropland. Nitrate content of groundwater under orchard was 9.3 mg?kg-1 (with the over-standard ratio 23.5%), which was 1.9 folds of that in cropland. The high concentrations of the nitrate in vegetables were measured, particularly green leafy vegetables ranked first with 2 685.5 mg?kg-1, followed by rhizome vegetables, cabbages and fruit vegetables. The over-standard ratios of rhizome vegetables, green leafy vegetables, fruit vegetables and cabbages were 80.9%, 37.9%, 29.7% and 2.2%, respectively. 【Conclusion】 It was revealed that the nitrate concentrations of soil, vegetable and groundwater were significantly or directly correlated with application levels of nitrogen fertilizer. Accordingly, soil nitrate accumulated obviously, vegetable and groundwater nitrate polluted severely both resulted from the high fertilization rate in vegetable field and orchard.

Key words: farmland, vegetables, groundwater, soil, nitrate