ผลของโดโลไมต์และคีเซอไรต์ต่อการเจริญเติบโตของต้นยางเล็ก

Abstract

Most of rubber plantation areas in Thailand are low magnesium (Extr. Mg) soils. It decreased growth and yield of rubber. This study investigated the effect of dolomite and kieserite on growth and nutrient uptake of rubber tree sapling. Budded stump RRIM 600 rubbers were planted in low extractable Mg soil (<0.30 cmol, Ms kg'). The experiments consisted of 2 experiments. 1) Rubber tree sapling were planted in soil containing 0, 0.5, 1.0, 1.5 and 2.0 cmol, Mg kg and as dolomite and 2) kieserite containing 0, 0.5 and 1.0 cmol, Mg kg with 5 replicates. The results showed that the applying Mg increased magnesium concentration in rubber. Application of 0.5 cmol, Mg kg made plant height and stem diameter highest than other treatments (P≤0.05). However, applying 2.0 cmol, Mg kg decreased rubber growth and calcium concentration in petiole, stem, primary root and lateral root (P≤0.05). Moreover, high Mg was likely to decrease potassium concentration in rubber and caused potassium deficient symptoms in leaf. Kieserite 0.5 mol, Mg kg' increased growth of rubber (P≤0.05). The applying kieserite increased magnesium, sulfur and chlorophyll concentration in leaf rubber. But high kieserite was likely to decrease potassium and calcium uptake in rubber (P≤0.05). Moreover, the applying dolomite (0.5 cmol, Mg kg") increased rubber growth but lower than kieserite treatments Most of rubber plantation areas are low magnesium soils. Mg application made response on growth of rubber. Kieserite application at 0.5 cmol. Ms kg" increased rubber growth better than dolomite. Therefore, rubber plantation areas should be applied Mg fertilizer as kieserite and considered appropriate nutrient management for rubber growth.