Silicon availability of the nursery bed soils and effects of silicon fertilizer applied on the growth and silicon uptake of rice (Oryza sativa L.) seedlings.

摘要

Silicon availability in 36 commercial nursery bed soils was evaluated by using four methods: the phosphate buffer (pH 6.2, 40 mmol litre-1), incubation, supernatant and acetate buffer (pH 4.0, 1 mol litre-1) methods. The influence of silicon availability in the nursery bed soils on the silicon uptake of rice (Oryza sativa cv. Hitomebore) seedlings and the effect of silicon fertilizer application were examined in a greenhouse in 2002. The results revealed that the best correlation between silicon content in rice seedlings and available silicon in soils was obtained with the phosphate buffer-solution method (r=0.86). More precise evaluation of available silicon was achieved by grouping soils based on these phosphate absorption coefficients (PAC). The correlation coefficients between silicon content in rice seedlings and available silicon in soils were 0.92 and 0.72 for volcanic soils (PAC>1500) and non-volcanic soils (PAC<1500), respectively. It is concluded that the phosphate buffer method is the most adjustable method for estimation of silicon availability in nursery bed soils. It is suggested that silicon fertilizers should be applied when silicon availability in non-volcanic nursery bed soils is below 200 mg kg-1, and less than 350 mg kg-1 in volcanic soils..