Abstract
The previous field trials on Sago palm cultivation in Malaysian peat under Nitrogen (N), Phosphorus (P) and Potassium (K) fertilizers application failed to produce a positive growth response. Consequently, the comparative studies reported herein were carried out on peat and mineral soils, both strongly acidic (pH <5), to elucidate on the problems encountered and proffer suitable fertilizer management options for Sago palms in peat soil. To achieve this, physicochemical characterization and ammonium (NH + ), phosphate (H2PO4 -) and potassium (K + ) sorption were carried out on both soils at their initial pH levels. The results of the nutrient sorption studies established that both soils, at comparable degrees, poorly sorbed the added NH4+ and K + ions at all levels of application. The quantity-intensity (Q-I) plots characteristics are: ammonium sorption (mineral soil: Ceo = 27.2 mg N/dm 3 -42.8 mg N/dm 3 soil; peat: Ceo = 35.7 mg N/dm 3 -66.0 mg N/dm 3 soil) and potassium sorption (mineral soil: Ceo = 13.0 mg K/dm 3 = -0.21 cmol(+) K/dm 3 soil and peat: Ceo = 19.2 mg K/dm 3 and -0.56 cmol(+) K/dm 3 soil). Ceo implies solution concentration when neither sorption nor the equilibrium solution concentration of the nutrient is zero. However, phosphate sorption plots showed both soils have very dissimilar P sorption properties. While the mineral soil sorbed a very high amount at all levels of P addition (Pmax = 1434 mg P/dm 3 soil), peat sorbed none at all. With its hydromorphic nature, this non-sorption of the added H2PO4 - by peat soil and its low sorption of the added NH4+ and K + will have far-reaching implications as regards mineral fertilizers use, the mobility of released NH4+, H2PO4 - and K + ions in soil and their utilization by Sago palm
Keywords:
phosphate
potassium
ammonium
sorption
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