Effect of spacing and nutrient levels on growth, yield and economics of fodder rice bean [Vigna umbellata (Thunb.)]

A field experiment was conducted at College of Agriculture, Vellayani, Trivandrum to standardize the spacing and nutrient levels of fodder rice bean [Vigna umbellata (Thunb.)]. The treatments consisted of three spacing (s₁-30 cm × 10 cm, s₂-30 cm × 20 cm and s₃-30 cm × 30 cm), three levels of nitrogen (n0-0 kg N ha⁻¹, n₁-20 kg N ha⁻¹ and n₂-30 kg N ha⁻¹) and three levels of phosphorous (p₀-0 kg P₂O₅ ha⁻¹, p₁-20 kg P₂O₅ ha⁻¹ and p₂-40 kg P₂O₅ ha-1). Result showed that sowing of rice bean at spacing of 30 cm × 10 cm (s₁) recorded highest plant height (49.04 cm) at 30 DAS and leaf: stem ratio (0.63) at harvest. The treatment n₁ (20 kg N ha⁻¹) resulted in highest plant height and it was on par with n₂ (30 kg N ha⁻¹), while leaf to stem ratio was the highest at n₂ at harvest. Similarly the highest green (14.57 t ha⁻¹) and dry fodder yield (2.91 t ha⁻¹) were recorded at spacing of 30 cm × 10 cm (s₁) and at n₂ (30 kg N ha⁻¹) resulting in greater net returns (Rs. 35, 761 ha_-1) and B: C ratio (3.22).