Effects of nitrogen in coated fertilizers on field vegetables
1999
Okumura, M. (Hokkaido. Central Agricultural Experiment Station, Naganuma (Japan)) | Miki, N. | Hasegawa, S. | Mino, K. | Tanaka, M.
We need to increase N use efficiency, by omission of the time of top-dressing during the growing period in the case of the use of rapid release N fertilizers and by improvement of fertilizer placement at basal application. Then, effects of basal application of Polyolefin coated fertilizers (slow-release fertilizers = SRFs) containing slow-release N on some typical field vegetables were estimated. (1) The relative yields were increased in Sweet corn and Welsh onions when 40 and 70 day types of SRFs were applied in bands along with the seed, respectively. The recovery of N is generally increasing and it is possible to omit top-dressings along the row on the way. (2) In contrast, the effect is low in such vegetables as Onions and Carrots which don't need top-dressing on the way, on which broadcasting of fertilizer is basally practiced. (3) In cabbage which has two cropping seasons, increasing effects were different among soils and the effect in the summer crop is higher than that in late spring. The advantage of utilization of SRFs is high in crops which need top-dressing, with more than 70 days for the growing period in the field and on which band application is possible. In addition, even though there is no difference in the rate of dissolution of SRFs, the good effects of SRFs are low in years and the cropping season in which precipitation is scarcer than usual. Especially in a low water retentive soil, the effect may be low in band application, because of a lowdiffusion of
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