Enhancing carbon sequestration in soil with coal combustion products: a technology for minimising carbon footprints in coal-power generation and agriculture

Abstract

Coal-fired power generation and agriculture account for more than half of global greenhouse gas emissions, but the coal fly ash (CFA) produced in the former can be a resource for reducing emissions from agriculture to minimise environmental footprints in both industries. Our aim in this study was to test how acidic and alkaline CFA addition could minimise loss of C and N from acidic soil, with or without added manure. We determined composition and structural characteristics of acidic and alkaline CFA for their capacity to adsorb organic carbon, but observed poor adsorption because of low concentrations of cenospheres and unburnt carbon as the primary absorbents in the ash. Addition of CFA had no impact on the loss of carbon or nitrogen from unmanured soil in which concentrations of these nutrients were low. Loss of carbon from manured soil was reduced by 36% with alkaline ashes and by 3-fold with acidic ashes; while loss of N was 30-50% lower with acidic ashes, but 28% higher with alkaline ashes, compared with no ash treatment. The increases in C sparing with CFA addition were achieved not by direct C absorption but by restraining microbial population and respiration, and potentially emissions. Alkaline CFA increased soil pH and if used to substitute just 10% of lime for ameliorating soil acidity would reduce CO 2 emission associated with the mining of the lime and its eventual dissolution in soil by ~ 2.66 Tg or 2.8% of Australia's annual agricultural emissions. High concentrations of oxides of phosphorus, silicon, titanium and clay particles in acidic ashes, and oxides of cations in alkaline ashes, were associated with potential for promoting C storage and acidity amelioration in soil.

Contrasting responses to soil and water salinity in stomata and canopy traits produced convergence of water‐use in tomatoes (Solanum esculentum) and okra (Abelmoschus esculentus): application to water management

“…Clemson's spineless were raised from seeds on vermiculite (electrical conductivity (EC) of 0.0 dS m −1 ) in plastic pots and watered with tap water (EC of 0.025 dS m −1 ), in which they germinated within 6 days and were allowed to establish for 2 weeks (8–12 cm high for okra and 10–18 cm for tomato). The seedling were then transplanted on 31 March 2012 into plastic pots (25 cm at the top, 19 cm at the base, 24 cm deep) filled with 6 kg each of loamy soil (83% sand, 10% clay and 7% silt) collected from the university research farm having a salinity of 0.018 dS m −1 and pH of 6.27 27 . Initial fertilisation was achieved by thoroughly incorporating into each pot 2 kg of soil sample that was pre‐mixed with 2.5 g compound fertiliser (12.2% N, 5.1% P, 13.7% K, 4.5% Ca and 1.1% Mg) as muriate of potash (CSBP Ltd, Bibra Lake, WA, Australia) just before transplanting.…”

“…The seedling were then transplanted on 31 March 2012 into plastic pots (25 cm at the top, 19 cm at the base, 24 cm deep) filled with 6 kg each of loamy soil (83% sand, 10% clay and 7% silt) collected from the university research farm having a salinity of 0.018 dS m −1 and pH of 6.27. 27 Initial fertilisation was achieved by thoroughly incorporating into each pot 2 kg of soil sample that was pre-mixed with 2.5 g compound fertiliser (12.2% N, 5.1% P, 13.7% K, 4.5% Ca and 1.1% Mg) as muriate of potash (CSBP Ltd, Bibra Lake, WA, Australia) just before transplanting.…”

Enhancing soil quality with coal fly ash amendment: a waste recycling approach for climate change mitigation in Indonesia - a review

“…Dissolved organic matter (DOM) is anticipated to be effectively adsorbed by cenospheric particle of CFA. Yunusa et al [31] also notes that the application of alkaline CFA mitigated carbon loss by up to 36%, while acidic CFA reduced total C loss threefold.…”

“…Subsequent soil aggregation offer additional physical protection to organic C, when organic C was covered and adsorbed by soil aggregate. Moreover, Yunusa et al [31] identifies the role of unburnt carbon and cenosphere particles in carbon adsorption. The two components serve as the primary adsorbents in CFA.…”