Nitrate in vegetable and its evaluation in suburb of Shanghai city

Vegetable is a kind of plant that accumulated much nitrate easily. Nitrate content is an important index to evaluate vegeta-ble quality. Agricultural intensity is very high in Shanghai, applying too much fertilizer has affected farmland environment in some extent. Research results indicated that, there was the highest content of nitrate in greenery vegetable growing in green-houses with average value 463.95 mg/kg, followed by leguminous vegetable with 141.91 mg/kg, melon vegetable with 102.38 mg/kg, nightshade vegetable with 38.81 mg/kg, and the lowest content of nitrate was found in edible fungus vegetable whose average value was 26.29 mg/kg. Both cultivation and cropping system could affect nitrate accumulation and transference in soil. Because of different man-agement manner, there was more nitrate in vegetable growing in green-houses, followed by growing in opened air, and then by tradi-tional vegetable. Pollution in greenery vegetable was the most serious with 57.1 percent samples’ nitrate content exceeding level I of the standard, and the pollution index was up to 3.50. Nitrate in leguminous, melon and nightshade vegetable was below the level I, which indicated that these vegetable were slightly polluted.