Effects of Powdered Rice Chaff on Growth and Yield of Rice Under Different Soil pH Conditions

Abstract

A recent rapid reduction in soil pH has been attributed to fertilizer mismanagement. The decomposition and consequent nutrient release from silicate rich organic material such as powdered rice chaff (Cp) could be affected by such reductions in pH. In the present study, rice plants were grown in either Cp or calcium silicate (Si-Ca) under various soil pH ranging from 5.5 to 7.5. The results show that the pH of soils gradually decreased at different growth stages in the case of pH 6.5 with Cp treatment. On the other hand, pH gradually increased at different growth stages of the rice plants when soil pH was initially 5.5, both with Cp and with calcium silicate. Nitrogen (N) and silicon (Si) contents of the plants decreased gradually with growth stage after the maximum tillering stage. The relationship between Si and N content in the plant at maximum tillering stage showed contradictory results. Si content was higher at pH 6.5 and at pH 5.5 with both Cp and calcium silicate treatments. On the other hand, N content was higher at pH 6.5 and at pH 7.5. Yield and yield components were significantly higher at pH 7.5 with Cp. These results suggest that Cp can be used as an alternative source of inorganic Si fertilizer. The mechanism by which the Cp acts under different pH nutritional conditions is unclear.

Keywords:

• Powdered rice chaff
• Silicon
• Soil pH

Acknowledgments

The authors gratefully acknowledge financial assistance from the Japanese Ministry of Education, Science, Sports, and Culture (MONBUSHO) Scholarship Program for Khandaker Akbar Hossain.