Effect of nitrogen application under restricted root culture system of satsuma mandarin [Citrus unshiu]
1999
Kawamura, S. (Shizuoka-ken. Citrus Experiment Station, Shimizu (Japan)) | Ooshiro, A. | Hisada, H. | Okada, N. | Katayama, H.
The suitable quantity of Nitrogen application under restricted root culture system of satsuma mandarin (Citrus Unshiu Marc.) was investigated. Furthermore, the effect of large nitrogen application on the growth of the tree and was investigated. 1) The quantity of applied nitrogen under restricted root culture system was investigated. When the volume of restricted root is 75 and 150 letter, the quantity of applied nitrogen per tree was 30g and 60g. In case of this quantity of applied nitrogen per tree was converted the quantity of applied nitrogen per unit area (10a), it's also 20kg. 2) If the quantity of applied nitrogen per 10a under restricted root culture system is suitable, it's lower than the standard quantity of applied nitrogen under popular culture. As a result, we get to be decreased the quantity of applied fertilizer. 3) When the effect of large quantity of applied nitrogen on the growth of the tree was investigated, nitrogen content of leaf is too high, and potassium content of leaf is too low. Therefore, the balance of nutrient of leaf was broken. And, when the effect of large quantity of applied nitrogen for soil was investigated, the exchangeable cation was decreased, as a result, the balance of exchangeable cation was broken, and the soil acidity is more strongly. 4) When the effect of large nitrogen application for the leaching loss from soil was investigated, large quantity of nitrogen was leached loss, and also the other fertilizer nutrient was leached loss. It's the problem on environmental protection and saving resources
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