Effects nitrogen fertilizers on nitrate accumulation in vegetables.

Influences of nitrogen rate, nitrogen sources, nitrogen fertilizer application frequency and bio-organic fertilizer on nitrate accumulation in vegetables were studied by methods of field experiment and lab analysis. Results indicated: nitrate content in vegetables increased significantly with increasing rate of nitrogen fertilizer; nitric nitrogen fertilizer was likely to accumulate nitrate in vegetables; multi-application of nitrogen fertilizer was helpful for reducing nitrate content in vegetables; application of chemical nitrogen fertilizer and bio-organic fertilizer together could not only increase yield of vegetables but also reduce nitrate content in vegetables.