IMPROVING FERTILITY OF ACID SULFATE SOIL USING VARIOUS LIME SOURCES FOR RICE GROWN IN MALAYSIA

Abstract

The main problems of acid sulfate soils are high acidity and Al and/or Fe toxicity to the soil. This problem causes rice root inhibition, hence retard plant nutrient uptake for its growth. Improving these conditions is important; hence, liming seems to be a common practice to ameliorate this soil, especially for rice cultivation. A study was conducted to evaluate the effects of applying ground magnesium limestone (GML), hydrated lime and liquid lime on the growth of rice under glasshouse conditions. MR 219 rice variety was used in this experiment. It was found that the application of 4 t ha-1 of GML had produced the highest rice yield of 8.2 t ha-1 under glasshouse condition. The result showed that as panicle length increase, spikelet per panicle also increases. Relative rice yield is negatively correlated with the soil pH, and this indicates that as soil acidity increase (observed with pH between 2 to 3), the rice yield decreases and vice versa. At harvest, due to liming practices, the soil pH exceeded 6 for all the treatment. It was also observed that as soil exchangeable Ca increase, soil pH also increases. Among the treatment, soil treated with 2 t ha-1 of hydrated lime gave the highest exchangeable Ca in the soil of 11.86 cmolc kg-1 soil with Ca concentration of 0.12% in the root. It was observed that liming increases soil pH and exchangeable cations in the soil. Therefore, liming is essential to ameliorate the acid sulfate soils for rice cultivation