Studies On The Nitrate Accumulation Situation And Controlled Index Of Applying Fertilizer In Vegetables In BaShang Region

For the ever-increasing serious nitrate pollution in vegetables today, the field investigation, micro-plot experiment and field experiment were respectively carried out in order to study the effect on the content of vegetables by applying fertilizers in BaShang region.For the results of field investigation, the nitrate pollution is not serious, the rest meet with the criterion expect for celery and radish, but the nitrate content of some kinds in leaf vegetables and root vegetables seem to be close to the criterion. The farmers should pay attention to the above in the region. Especially, by detailed investigation for Chinese cabbage, some results showed that the nitrate content was effected by different organ of the same breed and different seeding date.Some results were found form the micro-plot and field experiment, the remarkable relationship exists between nitrogenous fertilizer and the nitrate content in Chinese cabbage and celery, whereas phosphate fertilizer doesn't. In the Chinese cabbage experiment, the results showed that the nitrate content didn't exceed the criterion, although the quantity of N was increased. However, the rest exceeded the criterion except for the control treatment, B](NoPo) and B2(N2oP20), the highest rate of exceeding the criterion is 85.5%. The yield of Chinese cabbage and celery was increased remarkably with the coordinate applying N and P especially the micro-plot experiment, the yield of Chinese cabbage was increased by 155.5% with applying N fertilizer. The remarkable relationship exists between available N and total N in surface soil, and the nitrate content in vegetables. In the light of the residue situation of soil nitrate-N, the more the quantity of applying fertilizers is, the more the residue quantity in soil is. The residue reduces with the depth of soil horizon. The health of human body, economic benefit, environment, should be considered in order to define the reasonable applying fertilizer quantity. In Chinese cabbage experiment, pure N of 225kg/hm2 and pure P2Os of 135kg/hm2 areregarded as the recommend applying fertilizer quantity, pure N of 225kg/hm2 for cabbage.