Phosphorus application on grassland in andosols corresponding to phosphorus fertility in Konsen district [Hokkaido, Japan]
1990
Saigusa, T. (Hokkaido. Konsen Agricultural Experiment Station, Nakashibetsu (Japan)) | Matsubara, I. | Noshiro, M.
Regosolic, ordinary, and cumulic andosol are mainly distributed in Konsen District. Each has different physical and chemical properties from others. Phosphorus application on the grassland in each andosol corresponding to phosphorus fertility were estimated. 1) Al-p and Fe-p fraction increased with phosphate absorption coefficient. But, phosphorus with Bray No.2 and Ca-p fraction were decreased. 2) In the pot examination, phosphorus uptake by timothy was equal to decrease with Bray No.2 from regosolic andosol. But in cumulic andosol, the former was much more than the latter. On the other hand, the former was equal to decrease of inorganic phosphorus in any andosol. Timothy seemed to absorb phosphorus even from the fraction which was not extracted with Bray No.2. 3) In the field survey, when inorganic phosphorus per area in cumulic andosol was as much as that in regosolic andosol, the amounts of phosphorus uptake by timothy in the former were much more than that in the latter. The reason of differences on phosphorus fertility between regosolic and cumulic andosol seemed to also include physical properties of them. 4) The amounts of phosphorus with Bray No.2 were as follows to maintain high yield and phosphorus content of the grasses with standard fertility (80-100 kg/ha/year); Regosolic andosol: 30-60mg/100g, Ordinary andosol: 20-50mg/100g, cumulic andosol: 10-3-mg/100g. 5) When phosphorus with Bray No.2 was more than that, 40-50 kg/ha/year of phosphorus application permitted to maintain high yield, phosphorus content of the grasses, and legume ratio at least for 3 years. In the opposite case of it, 120-160 kg/ha/year of phosphorus application were needed
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