Impact of Cob rind biochar on soil physical, chemical, and biological properties under finger millet cultivation

Abstract

A field experiment was conducted at the PG Research Centre, Agricultural and Horticultural Research Station, Bavikere, University of Agricultural and Horticultural Sciences (UAHS), Shivamogga during kharif 2019 to evaluate the effect of cob rind biochar applied alone and in combination with farmyard manure (FYM) on soil physical, chemical, and biological properties under finger millet (Eleusine coracana L.) cultivation. The study included ten treatments consisting of cob rind biochar at 2 and 4 t ha- 1 combined with 75% and 100% recommended FYM, along with recommended dose of fertilizers (RDF) and an absolute control. Results showed that the integrated application of biochar and FYM significantly improved soil properties compared with biochar alone or RDF + FYM. The treatment receiving cob rind biochar @ 4 t ha- 1 + 100% recommended FYM (T8) performed best. It recorded the lowest bulk density (1.29 Mg m- 3), highest porosity (33.65%), and maximum water holding capacity (38.13%). Soil chemical properties also improved with increased pH, electrical conductivity, and soil organic carbon. Higher availability of nitrogen, phosphorus, potassium, and sulphur was observed in T8 compared with RDF + FYM and control. Micronutrient availability (Fe, Zn, Mn, and Cu) also increased with the combined application of cob rind biochar and FYM. Biological activity improved with higher microbial populations and greater enzyme activities such as dehydrogenase, phosphatase, and urease. Overall, the combined application of cob rind biochar (4 t ha- 1) and 100% FYM effectively improved soil health and fertility in finger millet cultivation