Effect of phosphorus enriched vermicompost on juice quality, ethanol yield and nutrient balance in sweet sorghum (Sorghum bicolor)

The work on enrichment of rock phosphate with vermi-compost and use of VAM is limited. Therefore, an experiment was conducted during 2008 and 2009 in sandy clay loam soil at Kathalagere, Karnataka to study the effect of phosphorus enriched vermin-compost on juice quality, ethanol yield and nutrients balance in soil after harvest of sweet sorghum [Sorghum bicolor (L.) Moench]. Results revealed that, application of 125 kg N + 50 kg K + vermi-compost enriched (VCE) with rock phosphate (RP), phosphorus solubilizing bacteria (PSB) and vescular arbuscolor mycorrhiza (VAM) resulted significantly higher grain (1.78 and 1.72 t/ha), millable stalk (30.7 and 29.6 t/ha), juice (10,472 and 9,934 l/ha), ethanol yield (492.2 and 465.2 l/ha), net returns (23,844/ha and 22,461/ha) and B:C ratio (2.59 and 2.5) during 2008 and 2009, respectively and which was on par with the application of 125 kg N + 50 kg K + VCE with RP and PSB. Whereas, application of 50 kg N + 20 kg K + VCE with RP, PSB, VAM and Azatobacter recorded significantly lower grain, millable stalk, juice, ethanol yield, net returns and B:C ratio. The uptake of nitrogen, phosphorus and potassium by crop was significantly higher with the application of 125 kg N + 50 kg K + VCE with RP, PSB and VAM during both the years of experimentation.