Effect of biochar on soil properties and lead (Pb) availability in a military camp in South West Ethiopia

Abstract

Application of biochar to soil can improve numerous physicochemical and biological properties of the soil. The method for lead metal (Pb) remediation in soil is a challenge worldwide. The excessive Pb accumulation in the soil can radically reduce the soil quality and fertility. This study was conducted to find out the efficiency of biochar in improving the physicochemical properties of soil and to evaluate its effect on Pb availability in a military camp soil. Soil sample was collected from military camp of Jimma town, southwestern Ethiopia and was incubated for 90 days with different application rates (0, 2.5, 5, 7.5, 10, 12.5 and 15 t/ha) of biochar. The results showed that the addition of biochar improved, pH, electric conductivity (EC), cation exchange capacity (CEC), organic carbon (OC), organic matter (OM), total nitrogen (TN), exchangeable cations and available phosphorous of the soil and had no significant effect on soil texture. Sequential extraction of Pb showed that at 15 t/ha (4.2 g/kg) application of biochar, the exchangeable form of Pb significantly transformed the carbonate bound, Fe/Mn oxide bound, organic bound and residual fractions to 66.79, 100.5, 112.7 and 112.1 mg/kg, which is reduced by 88.6, 88.9, 88.5 and 88.3%, respectively as compared to the control. It is concluded that the application of biochar could not only improve physicochemical properties of the soil but also stabilize Pb in a military camp soil.

Rice straw biochar improves soil fertility, growth, and yield of rice–wheat system on a sandy loam soil

“…Relationships between soil fertility, plant nutritional status, and grain yield Significant positive correlations recorded between the mineral-N, available P, and available K contents in soil and P and N concentration in aboveground biomass of wheat suggested that biochar and RHA supplied significant amounts of these nutrients to plants (Figure 1). Higher bioavailability and release of biochar's N, P, and K in soil have been reported in a number of earlier studies (Bayu et al, 2016;Mete et al, 2015;Yu et al, 2009). Among the soil fertility parameters, SOC content showed significant correlation with wheat grain yield (Figure 2).…”

Reclaiming Sodium Affected Soil: The Potential of Organic Amendments

“…Soil pH influences the availability of plant nutrients. The decrease in soil pH following the application of biochars and poultry manure contradicts the findings of [13][14][15] all of whom recorded increased pH after the application of biochar and compost. It is however worth to note that the impact of biochar/manure application on soil pH would be much influenced by the properties of the feedstock from which they are prepared.…”

“…In an Iowa study, [17] found a significant increase in Ca 2+ levels when biochar was applied to soil at 20 g Kg -1 soil. [13][14][15] also observed significantly increase in the levels of Ca +2 , Mg 2+ , K + and Na + following the application of biochar and compost. Per these research findings, therefore, biochar could be a significant source of these cations [4] and could potentially help in sodic soil remediation.…”

Enhancing Cation Exchange Capacity of Weathered Soils Using Biochar: Feedstock, Pyrolysis Conditions and Addition Rate

“…The presence of K in the feedstock alters C degradation due to a greater thermal stability of organic compounds formed during pyrolysis [54]. In another study, the addition of 15 t ha −1 coffee husk biochar (pyrolyzed at 500 • C) in an acid soil also increased the CEC from 24.9 to 34.9 cmol c kg −1 after three months of incubation as a result of the high CEC of the biochar (79 cmol c kg −1 ) [37]. For both clayey and medium texture soils used in this study, the CEC values are the highest already reported for Brazilian weathered soils.…”

“…Although several studies report positive contribution of biochar to soil CEC [37][38][39], the mechanism behind soil CEC increase in short and medium-term experiments is not clear [40,41]. In that direction, the evaluation of CEC of soils amended with biochar should be supported by other studies based on the use of tailored biochars from feedstocks exposed to variable temperatures and added to soils with varying OM and clay contents.…”