Effects of carbonised rice hull and duckweed (Lemna minor) in rice (Oryza sativa) seedling growth

Abstract

Carbonised rice hull (CRH) is an excellent soil fertiliser and conditioner because it includes micronutrients necessary for crop growth such as phosphorus, potassium, calcium, and magnesium. Duckweed (Lemna minor), an aquatic plant, can grow in wastewater, ecologically clean the water by accumulating nutrients, and provide a byproduct that can substitute for or augment synthetic fertilisers. Field experiments were conducted in May and November 2019 to evaluate the effects of CRH and a combination of CRH and duckweeds on rice seedling growth. This study tested the hypothesis that the addition of duckweeds and CRH as amendments or alternative fertiliser will improve rice seedling growth. Parameters measured such as plant height, root length, leaf length, and nutrient composition of CRH and duckweeds. Three treatments were used (control no application, CRH, and CRH combined with duckweeds). Results of the study showed a significant variation in growth parameters between the treatment with combined duckweed and CRH compared with application of CRH alone and no application. Longer roots, longer leaves and taller rice seedlings were also obtained from the treatment of CRH combined with duckweeds. Results suggest that incorporation of CRH in combination with duckweed in seedbed preparation could enhance the growth of rice seedlings and could be an alternative source of nutrients for the growing rice seedlings since the said alternative materials (duckweeds and CRH) contain necessary nutrients such as nitrogen, phosphorus, potassium, and micronutrients such as zinc. Findings suggest that duckweed may be an environmentally and agriculturally sound substitute for synthetic fertiliser. Using these materials may also lessen the cost of production with better crop standing.