Residual effect of micronutrients and sulfur enriched phyto-biochars soil applied to fodder maize on yields, tissue concentration and uptake of nutrients by rice and post-harvest soil properties

The residual effect of low doses of lantana, pine needles and wheat straw phyto-biochars pyrolyzed at 300 °C and 450 °C and enriched with 0, 50, 75 and 100% of recommended doses of fertilizers (RDF) of micronutrients and S was studied on the yields, nutrient concentration and uptake of second crop, i.e. rice (Oryza sativa L.) after fodder maize to validate their nutrient slow-release characteristics. The residual effect of phyto-biochars averaged over different RDF increased rice grain yield significantly under lantana and pine needles phyto-biochars pyrolyzed at 300 °C, but decreased with pine needles biochar pyrolyzed at 450 °C as compared to the control. The highest grain yield (9.43 g pot−1) was under pine needles phyto-biochar pyrolyzed at 300 °C and enriched initially with 75% of RDF, which was 7.8 per cent higher than that with 75% of RDF applied through conventional fertilizer sources. The residual effect of some treatments significantly increased the readily oxidizable C and extractable Zn, Cu, Fe, Mn, B and S in the soil after rice harvest. For fodder maize + rice crops together, pine needles phyto-biochar pyrolyzed at 300 °C or lantana phyto-biochar pyrolyzed at 450 °C with enrichment of 75% RDF of micronutrients and S gave the higher apparent per cent utilization of Zn, Fe, Mn, and S, but numerically closer per cent utilization values for Cu and B in comparison to the conventional chemical fertilizer sources.