Integrated weed and fertilizer management for sustainable weed control and improved productivity of upland rice

Abstract

Gains in yield and profitability of upland rice (Oryza sativa L.) resulting from integrated fertilizer and weed management practices were studied during the wet seasons of 2002 and 2003. Grain yield increased by 0.85 t ha⁻¹ with integrated weed and fertilizer management and 0.33 t ha⁻¹ with recommended weed management practice over farmers' practice of weed control. Mean weed biomass comprised between 6.2 and 65.6% of the combined biomass of weeds and rice at flowering stage. Weeds on an average caused 79.4% losses in rice yield when left uncontrolled compared to farmers' practice. The mean value:cost ratios were between 1.36 and 4.72 for different weed control treatments. Reduction in nutrient depletion by weeds due to integrated fertilizer and weed management was 28.2 kg N ha⁻¹, and 2.4 kg P ha⁻¹ compared with the weedy control whereas butachlor applied alone at 2.0 kg ha⁻¹ saved 25.8 kg N ha⁻¹ and 2.2 kg P ha⁻¹. Application of 1.5 kg ha⁻¹ Butachlor supplemented by single mechanical hand weeding and integrated with modified fertilizer (N and P) schedule appeared the most productive practice besides controlling weeds to a satisfactory level.

Keywords:

• value:cost ratio
• nutrient uptake
• dry weed biomass
• mechanical hand weeding
• fertilizer application schedule