Evaluation of paper mill lime sludge as an acid soil amendment in Northeast Thailand

Abstract

The objective of the studies was to evaluate the appropriateness of paper mill lime sludge for liming through its chemical composition, its effects on the chemical properties of an acid Oxic Paleustult, and on growth of corn plants in this soil in a greenhouse and a field experiment. Treatments in the greenhouse experiment consisted of a factorial combination of 5 rates of lime sludge (0, 312.5, 625, 1250 and 2500 kg ha-1) and 3 rates each of K and Mg (0, 0.25, and 0.5 cmol kg-1), while those of the field experiment were the 5 rates of lime sludge only. The lime sludge had a high calcium carbonate equivalent (91.3%), it increased soil pH, Bray II extractable P and exchangeable Ca and decreased exchangeable Al and H contents, as application rate increased. However, increased levels of soil Na and Cl occurred at high rates of application of lime sludge. Increased rates of K, Mg and lime significantly increased corn top yields in the greenhouse experiment. However, corn yield was significantly decreased by 625 kg lime sludge ha-1 when K was applied at the highest rate. Inadequate Ca and Mg concentrations in corn, especially at the highest K rate, were associated with the yield depression. Maximum top yields in both experiments were obtained at 312.5 kg lime sludge ha-1.