Management of Agro-Industrial Waste Application in the Field Increases Soil Organic Carbon Concentration in an Acidic Soil

Abstract

ABSTRACT The objective of this study was to evaluate the effects of biomass ash management in a pasture area under maintenance on the total accumulated soil organic carbon and carbon in soil organic matter fractions over five years of management. The experiment was carried out under field conditions. The soil of the region is an Oxisol cultivated from Urochloa brizantha. The experimental design consisted of randomized blocks in a strip scheme with five doses of biomass ash (0, 8, 16, 24, and 32 tha−1) and two application methods (incorporated, and unincorporated) with four replications. The variables analyzed were total organic carbon and carbon in the fractions of particulate organic matter and associated with minerals. The use of biomass ash as a soil fertilizer provides conditions for greater carbon storage in the soil in the medium term. In addition to presenting greater carbon storage in the most stable fraction of the soil, that associated with minerals. Unincorporated biomass ash provided the best results, significantly increasing soil organic carbon concentrations in both total organic carbon and the mineral-associated fraction. Overall, the surface application of biomass ash enhances carbon accumulation in the soil, particularly within the most stable organic matter fraction, demonstrating its potential for medium-term soil carbon storage. GRAPHICAL ABSTRACTA flowchart illustrating sustainable agriculture through biomass ash. The process begins with ′Regenerative Agriculture′ linked to goals: ′Zero Hunger′, ′Responsible Consumption and Production′ and ′Climate Action′. It leads to ′Use of plant biomass in agroindustry′, depicted by logs and machinery. Next is ′Application of ash residue in agriculture′, shown with a factory and ash piles. This connects to ′Incorporated biomass ash′ and ′Unincorporated biomass ash′, showing soil with higher organic carbon storage. Finally, ′Increased carbon storage in soil′ is depicted with a farm scene, completing the cycle.Flowchart on sustainable agriculture: biomass ash, regenerative farming, carbon storage.