Effect of nitrogen applicaiton on nitrate concentration in Chinese cabbage [Brassica chinensis]
2007
Uezono, I.(Kagoshima-ken. Inst. for Agricultural Development, Minamisatsuma (Japan)) | Mochida, T.
We examined the effect of the harvest period and the nitrogen fertilizer application exerted on the accumulation of nitrate concentration in Chinese cabbage. 1. The total nitrogen content in the top of Chinese cabbage decreased until about 100 days after planting in usual fertilization that is basal dressing (just before planting) and twice side dressing (15 and 33 days after planting). On the other hand, both nitrate-nitrogen content and nitrate content were the highest on 40 days after planting (7 days after second side dressing). The nitrate content in head formation was lower than that in outer-leaf in harvest period. 2. The nitrogen of basal dressing and first dressing gave same influence to accumulation of nitrate concentration in the outer-leaf and the head formation. On the other hand, the influence to accumulation of nitrate concentration by second dressing in the head formation was larger than that of the outer-leaf. 3. With delaying second dressing, nitrate concentration increased but fresh weight and total nitrogen absorption of Chinese cabbage decreased. The delaying second dressing increased nitrate in outer-leaf compared with that in head formation. Furthermore, if we used nitrogen fertilizer include of nitrate-nitrogen for second dressing, the nitrate concentration in Chinese cabbage rose more. 4. From these results, the Chinese cabbage cultivation under the usual fertilization, it's feared that the nitrate concentration would rise by the delay of last dressing and the early harvesting.
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