Soil Respiration and Organic Carbon Response to Biochar and Their Influencing Factors

Abstract

Biochar application is an important measure to regulate SOC. However, the effects of biochar application on soil respiration and SOC fraction of the saline soil have been scarcely investigated. Therefore, in this study, we monitored the annual SOC, nutrients, temperature, water content, and respiration rate under three maize-straw-derived biochar application doses (0, 15, and 30 t∙hm−2). Biochar enriched the soil in terms of fast-acting potassium and phosphorus, alkali-hydrolyzable N, NO3−-N, and NH4+-N to varying degrees. One-time biochar application in the trial year continued to fertilizer retention in the following year. Mineral-associated organic carbon and SOC contents increased with time after biochar application, whereas the changes in particulate organic carbon content were the opposite; soil respiration rate was reduced by 7.7–14.7%, and the reduction increased with the dose as well in successive years. The soil respiration rate and soil temperature showed a significant linear correlation, but the application of a high amount of biochar reduced the correlation between the two. Considering the soil respiration rate and physicochemical properties, the best biochar application rate for saline soil is suggested to be 30 t∙hm−2. This study is of great significance for soil carbon sequestration, emission reduction in saline areas, and the realization of a “carbon peak” in the sense of farmland.

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

“…The very low initial organic carbon (1.32%) and macronutrient status of the acid soil studied mediated this reaction pathway such that a large proportion of the organic carbon built up following biochar application was channeled first into enhancing the soil macronutrient pool. A similar observation has been reported by Zhang et al 39 . The organic carbon and exchangeable acidity statuses of the soil after cowpea seedling harvesting are showing the need for further carbon build-up in the soil to achieve a situation where further increases in SOC content will account for a negative correlation with exchangeable acidity.…”

Enhancing the Anaerobic Biodegradation of Petroleum Hydrocarbons in Soils with Electrically Conductive Materials

“…also apply to the biochar-supplemented microcosms: the lower apparent CO2 accumulation in the headspace with respect to the control microcosms might be due to the slight alkalinisation of the soil triggered by the biochar. Along this line, it is worth noting that recent studies have reported a decrease in soil respiration following biochar addition [51]. Methane, which is the other gaseous end-product of organic matter decomposition under anaerobic conditions, remained below the instrumental detection limit in all treatments during the whole experimental period.…”

“…Similar considerations also apply to the biochar-supplemented microcosms: the lower apparent CO 2 accumulation in the headspace with respect to the control microcosms might be due to the slight alkalinisation of the soil triggered by the biochar. Along this line, it is worth noting that recent studies have reported a decrease in soil respiration following biochar addition [ 51 ].…”

Enhancing Sustainable Agriculture in China: A Meta-Analysis of the Impact of Straw and Manure on Crop Yield and Soil Fertility

“…In SOC and soil nutrients, straw biochar had the biggest effect value on SOC, but there was no significant difference with straw mulching on TN, AP, and AK. Straw biochar can significantly uplift the contents of available soil nutrients and SOC sequestration due to its physicochemical characteristics [72,73]. Compared with straw incorporation, straw mulching significantly increased TN, but there was no significant difference between straw incorporation and straw mulching in improving AP, AK, and SOC.…”