Comparative analysis of nutrients composition in biochar produced from different feedstocks at varying pyrolysis temperature

Abstract

Biochar has proved to be effective in improving soil fertility and it is important to know its nutrients variability as influenced by pyrolysis temperature and feedstock type for optimum agricultural productivity. In this experiment four different feedstocks from animal and plant sources were selected and pyrolysed at four different temperatures of 300, 400, 500 and 600 ˚C for 3 hours at a heating rate of 10 ˚C min -1 . The feedstocks were Corn cob (CC), Poultry litter (PL), Cow dung (CD) and Peanut shell (PS). The results showed that increase in pyrolysis temperature led to decrease in the concentration of many of the parameters analysed in the biochar. At the lowest temperature of 300 ˚C the highest contents of (0.62 %) N in CD, (66.4 mg g -1 ) P in CC, (8.38 mg g -1 ) K in CD, (16.2 mg g -1 ) Ca in CC, (4 21 mg g -1 ) Mg in CC, (0.28 %) S in CC, were observed. On the other hand, increase in temperature resulted to increase in C, pH, Ash content and the highest pH value of 10.17 was found in CD. From this study, it can be deduced that feedstocks from animal source shows a high range of nutrient when compared to feedstocks from plant source and likewise increase in temperatures led to decrease in some essential nutrient needed by plant for growth and stability in the soil.

Biochar and Its Broad Impacts in Soil Quality and Fertility, Nutrient Leaching and Crop Productivity: A Review

“…Biochars produced from animal manures, crop residues, and seaweeds are richer in nutrients, possess higher pH, and contain less stable carbon than woody biochar [1,31,41,42]. Omotade et al [43] applied biochar of maize cobs, peanut shells, cow dung, and poultry litter pyrolyzed at 300-600 • C for 3 h. Results from this research showed that the highest contents of N (0.62%) and K (16.2 mg g −1 ) were found in cow dung, P (66.4 mg g −1 ), Mg (0.28%), and sulfur (S; 0.28%) in maize cob, and Ca (4.21 mg g −1 ) in peanut shell. Thus, wood-based biochars are suitable when the final objective is carbon storage in soil [44,45], while biochars from animal manures and grasses are used when the objective is to increase the soil N, P, K, Ca, Mg, and S contents [45,46].…”

Soil Acidity Ameliorative Potentials of Biochar from Sawdust and Tithonia diversifolia Feedstock

“…Commonly distributed annual luxuriant weeds such as Tithonia diversifolia and Imperata cylindrica in Southwestern Nigeria can be a potential feedstock for biochar production against woody products with existing and increasing competitive uses. Biochar produced at a slow pyrolysis temperature range of 300-450°C are reported for their potentially higher fertilizer properties as macronutrients such as N and P are lost as pyrolysis temperature increases 22 . The peculiarity of the acid soil studied characterized by low macronutrients (N, P and basic cations) and organic carbon calls for the need for its management with specially modified amendments that would serve as both liming and fertilizer materials.…”