Improving soil silicon and selected fertility status for rice production through rice-mill waste application in lowland sawah rice field of southeastern Nigeria

Abstract

Purpose: Rice-mill wastes are generated in large amounts in Ishiagu, Ebonyi State, Nigeria. These wastes can potentially be utilized for rice production and in improving soil attributes. This study evaluated the effects of rice-mill wastes on soil chemical properties and rice yield in sawah rice management. Methods: A sawah rice field in an inland valley of southeastern Nigeria was used in 2014 and 2015 cropping seasons for the study. Sawah refers to an Indo-Malaysian term for rice paddy. It involves the manipulation of some soil physical properties in form of ecological engineering works, by bunding, puddling and leveling of lowland rice field for water control and management. Two rice-mill wastes [rice husk ash (RHA) and rice husk dust (RHD) applied at 0, 2.5, 5, 7.5, 10 and 12.5 t ha−1] and the control were built into a split-plot in a randomized complete block design with three replications. Results: Bio-waste application had significant (p < 0.05) improved effects on the soil organic carbon, available P, soil available Si and total N compared with the unamended (control) treatment. There was significant (p < 0.05) increase in rice grain yield from 5.05 to 5.80 t ha−1 (for RHA) and 6.17–6.96 t/ha (for RHD) compared with 2.35–2.8 t ha−1 (control treatment) in both cropping seasons. Conclusion: RHD and RHA treatments had significantly higher rice grain yield compared with the control treatment. Overall, rice grain yield was higher under RHD treatment compared with RHA treatment. This result demonstrated that RHA and RHD are potential agricultural resource for rice production in the study area.