【摘要】 在不同季节对 1 1类、48种蔬菜的测定表明 ,硝态氮含量高于 3 2 5mg·kg- 1,达到 4级污染水平的有 2 0种 ,占调查总数的 41 7% ,包括全部叶菜类、部分瓜类、根菜类和葱蒜类蔬菜 .其中硝态氮含量高于 70 0mg·kg- 1,超过 4级污染水平的有 5种 ,均为叶菜类蔬菜 .叶菜硝态氮累积虽为严重 ,但其中部分蔬菜叶片的硝态氮含量却低于 3级污染水平 .对不同类型菜地和农田土壤的测定发现 ,菜地 0～ 2 0 0cm各土层的硝态氮残留量均高于农田土壤 ,常年露天菜地 2 0 0cm土层的硝态氮残留总量为 1 3 5 8 8kg·hm- 2 ,2年大棚菜田为 1 41 1 8kg·hm- 2 ,5年大棚则达1 5 2 0 9kg·hm- 2 ,而一般农田仅为 2 45 4kg·hm- 2 .菜地土壤的硝态氮残留严重威胁菜区地下水环境 .更多还原

【Abstract】 Determinations of 11 kinds, 48 varieties of vegetables were carried out at different seasons. The results showed that nitrate\|N concentrations in 20 vegetables reached Pollution Level 4 (NO - 3\|N>325 mg·kg -1 ), which accounted for 41 7% of the total number of the sampled vegetables and included all of the leafy, and most of the melon, root, onion and garlic vegetables. Among them, 5 leafy vegetables even exceeded Level 4 (NO - 3\|N>700 mg·kg\+\{-1\}). Although leafy vegetables were usually apt to heavily accumulate nitrate, most of them were with nitrate\|N concentrations lower than Level 3 (NO - 3\|N<325 mg·kg -1 ) in leave blades. Further investigation showed that vegetable soils accumulated more nitrates in each layer from 0 cm to 200 cm than did cereal crop soil. The total amount of residual nitrate\|N was 1358\^8kg·hm -2 in the 200 cm soil profile of usual vegetable fields, and 1411 8kg·hm\+\{-2\} and 1520\^9kg·hm -2 in the 2\|yaers and the 5\|years long plastic greenhouse fields respectively, however that in the cereal crop fields was only 245\^4 kg·hm -2 . Nitrate residual in vegetable soils formed serious threats to underground water in vegetable growing areas.更多还原