[Potassium fixation of some soil types of Fluvisols in Viet Nam]
2000
Nguyen Huu Thanh | Kazuhiko Egashira
Some soil units of fluvisols were studied for fixation of potassium (K). Studies of K fixation in the soil were conducted by evaluating the effect of applied K on the extractability of K with time. A series of five K-sorption treatment solutions, 0.11, 0.22, 0.45, 0.90 and 1.80 cmol/kg were prepared and applied as potassium chloride (KCl) to soils. The soil samples were extracted with normal ammonium acetate (1N NH4CH3COO) extractant for K after five to seven days of incubation. The amount of K fixed was determined. With increase in the concentration of K added, the amount of K fixed increased for soils, but the magnitude of the K fixation rate varied widely among the soils. The highest K fixation rate (62.7 to 76.9 percent) was observed in the subsoil of Eutric Fluvisols of Red River plain. The lowest K fixation rate (20.7 to 40.9 percent) was detected in Thionic Fluvisols and Dystric Fluvisols of Thai Binh River plain had medium K fixation rate (28.2 to 46.4 percent)
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