Rice farming components for biological weed control in transplanted rice: perspective on weedy rice management

Abstract

Farming elements other than the crop, when integrated into the system, are supplementary, with multifold uses that include weed and pest management. Elements such as fish and poultry birds are integrated with transplanted wetland rice (Oryza sativa L.) for ensuring farmers’ livelihoods and the nutritional security and sustainability of the system. Integrated animal components such as poultry birds and fish also supplement the system with weed control. The role and efficacy of these animal components as tools for managing weedy rice (Oryza sativa L.) were explored, as weedy rice infestation is increasing. This threat of weedy rice is due to scarcity of water resulting from poor water management and improper field leveling. Grass carp (Ctenopharyngodon idella val.) produced the highest reduction of weedy rice biomass, 28% within 24 h under laboratory conditions. Polyculture of C. idella, mrigal (Cirrhinus mrigala Ham.), and silver carp (Hypophthalmichthys molitrix val.) reduced the biomass of weedy rice by 21% within 24 h. In laboratory studies, poultry manure at the highest concentration of 5% reduced the weedy rice seed germination 100% compared with rice seed germination at 91%. This conformed with microplot experiments in which poultry manure at 15.6 g d⁻¹ resulted in a weed control index (WCI) of 8% in both years. However, poultry manure at 15.6 g d⁻¹ in combination with herbicide application resulted in the highest control indices of weedy rice: 52% in 2017 and 2018. Integrating fish and poultry with PRE application of oxyfluorfen (0.25 kg ha⁻¹) resulted in the highest WCI and grain yield in field experiments.