Characterization of biochars prepared from different plant wastes and their use as source of micronutrients
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Date
2021-02
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Six biochars were prepared from three different plant biomasses at two incineration temperature. They were characterized in the laboratory. A pot experiment was also conducted in the net house of Department of Soil Science, G.B.P.U.A.&T., Pantnagar to study the effect of different biochar addition and micronutrients + S doses on dry matter yield, nutrient concentration, nutrient uptake by hybrid Maize (Zea mays L., cv. NMH-589) and soil properties after maize harvest (60 d). Treatments imposed were six different biochars (0.5 t/ha) along with a control (no biochar addition) and four graded levels of different micronutrients+ S (equivalent to 0, 50, 75 and 100 percent) in an asymmetrical factorial completely randomized design with three replications. The present study revealed that biochars were highly carbonaceous residues and the properties of biochars change with the nature of source and also with the increase in the incineration temperature. The concentrations of Zn, Cu, Fe, Mn and B in the biochars were found to be significantly increased with the increase in the incineration temperature from 300 to 450 °C. The adsorption kinetics of micronutrients and S on biochars conformed best to the pseudo-first order kinetics. The concentration dependent adsorption-desorption studies of biochars revealed that they followed Freundlich isotherm model. An increase in incineration temperature significantly increased the adsorbed amount of Zn, Cu, Fe, Mn and B onto biochars but decreased the percent desorption of these micronutrients. The interaction effect of biochar source and incubation temperature had varying effects on adsorption and percent desorption of micronutrients and S. Pot experiment revealed that with application of wheat biochar (W300) and 75 percent of micronutrients+ S doses the highest dry matter yield was obtained. The Zn and Fe uptakes were found to be significantly influenced by the biochar addition, different micronutrients+ S doses and interaction effect of these two variables. Application of 50%, 75% and 100% micronutrients+ S doses significantly increased Mn and B uptake of maize. The interaction effect of biochar addition and application of different micronutrients+ S doses failed to significantly influence Cu, Mn, B and S uptake of maize crop. After the harvest of maize, higher soil pH and EC were recorded under biochar addition and different micronutrients + S doses. The soil organic C showed a significant but minor increase only under the application of the W300 biochar. The highest DTPA extractable Fe, Mn content and 0.15% CaCl2 extractable S content were recorded in treatment combination receiving P300 biochar with application of 100 % micronutrients+ S dose. Thus, biochar can be considered as a good source and carrier of micronutrients and S to improve maize biomass yield and the soil quality.