Growth, Green Forage Yield and Quality of Sorghum (Sorghum bicolor) Fodder as Influenced by Application of Phosphorus Fertilizer

A field experiment was carried out in kharif 2014–15 in order to gain the better understanding of the effect of various levels phosphorus fertilizer on yield and nutritional values of sorghum fodder at three cuttings. The experiment was conducted using five levels of phosphorus fertilizer viz. 0 (T₁), 40 (T₂), 80 (T₃), 120 (T₄) and 160 (T₅) kg P₂O₅ha⁻¹ in RBD. A significant effect of phosphorus fertilizer application on plant height was observed with 120 kg P₂O₅ ha⁻¹ at 60 days in 1ˢᵗ cutting and at 15 and 30 days in both 2ⁿᵈ and 3ʳᵈ cuttings. Significantly higher green fodder yield and dry matter yield were obtained at 120 kg P₂O₅ ha⁻¹ in all the three cuttings. Similarly significantly higher total green fodder yield (41.38 MT ha⁻¹) and dry matter (6.12 MT ha⁻¹) were obtained in T₄i.e 120 kg P₂O₅ ha⁻¹. Total green fodder yield at 120 kg P₂O₅ ha⁻¹ was increased by 35.5%, 20.6%, 14.7% and 17% over the green fodder yield at 0, 40, 80 and 160 kg P₂O₅ ha⁻¹. Significant difference in CP content was observed in 1ˢᵗ and 2ⁿᵈ cutting but in 3ʳᵈ cutting the difference was not significant. However higher crude protein (CP) content was recorded at 120 kg P₂O₅ ha⁻¹ in all the three cases. Crude fibre (CF) content was decreased significantly with the increased dose of phosphorus in all the three cuttings. CF of sorghum also gradually decreased from 1ˢᵗ to 3ʳᵈ cuttings. Effect of phosphorus on total ash (TA) content was found not significant in all the three cuttings. Ether extract (EE) and Nitrogen free extract (NFE) were increased significantly with the application of phosphorus in all the three cuttings. Though highest EE value was recorded at 160 kg P₂O₅ ha⁻¹ but significantly highest NFE was observed at 120 kg P₂O₅ ha⁻¹in allthe three cuttings of sorghum. Based on the above findings it can be concluded that application of phosphorus at the rate 120 kg ha⁻¹ significantly increase the green fodder yield as well as the nutritional values of sorghum.