Jampen Onthong, Surachart Pechkeo, Sayjai Gimsanguan, and Narong Malee

pp. 655 - 667

Abstract

Application of lime and gypsum for alleviation of aluminum toxicity in acid soil, including potassium (K) fertilization, may interfere with the nutrient uptake of longkong (Aglaia dookkoo Griff.) trees. Three experiments were conducted to explore the possible problem of longkong soil. 1) Effect of lime and gypsum on growth and nutrient uptake of longkong seedling. 2) Effect of lime and potassium chloride on potassium and magnesium uptake of longkong. 3) Relationship between potassium, calcium and magnesium in longkong leaves. The results showed that exchangeable aluminum in the soil decreased with the increase of Ca(OH)₂ treatment and the application of lime was more effective than that of the gypsum treatment. The
application of lime and gypsum tended to increase nutrient concentration in longkong, but did not affect the growth of longkong seedlings. The lime application on nutrient uptake of longkong seedlings decreased K
uptake; no lime and lime treatments were 863 and 720 mg tree^-1, while without K applied the per tree uptakes were 579 and 356 mg tree^-1 respectively. Besides the K application treatment reduced Ca and Mg uptake. Negative correlations between K and Ca (r = -0.532**) and between K and Mg (r = -0.663**) in leaves of 60 longkong trees in a farmer's orchard were found.