title: Benefits of biochar, compost and biochar-compost for soil quality, maize yield and greenhouse gas emissions in a tropical agricultural soil.
abstract: Soil quality decline represents a significant constraint on the productivity and sustainability of agriculture in the tropics. In this study, the influence of biochar, compost and mixtures of the two on soil fertility, maize yield and greenhouse gas (GHG) emissions was investigated in a tropical Ferralsol. The treatments were: 1) control with business as usual fertilizer (F); 2) 10 t ha(-1) biochar (B)+F; 3) 25 t ha(-1) compost (Com)+F; 4) 2.5 t ha(-1) B+25 t ha(-1) Com mixed on site+F; and 5) 25 t ha(-1) co-composted biochar-compost (COMBI)+F. Total aboveground biomass and maize yield were significantly improved relative to the control for all organic amendments, with increases in grain yield between 10 and 29%. Some plant parameters such as leaf chlorophyll were significantly increased by the organic treatments. Significant differences were observed among treatments for the δ(15)N and δ(13)C contents of kernels. Soil physicochemical properties including soil water content (SWC), total soil organic carbon (SOC), total nitrogen (N), available phosphorus (P), nitrate-nitrogen (NO3(-)N), ammonium-nitrogen (NH4(+)-N), exchangeable cations and cation exchange capacity (CEC) were significantly increased by the organic amendments. Maize grain yield was correlated positively with total biomass, leaf chlorophyll, foliar N and P content, SOC and SWC. Emissions of CO2 and N2O were higher from the organic-amended soils than from the fertilizer-only control. However, N2O emissions generally decreased over time for all treatments and emission from the biochar was lower compared to other treatments. Our study concludes that the biochar and biochar-compost-based soil management approaches can improve SOC, soil nutrient status and SWC, and maize yield and may help mitigate greenhouse gas emissions in certain systems.
authors.affiliation: College of Science, Technology and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, PO Box 6811, Cairns, Queensland 4870, Australia.
authors.forename: Getachew
authors.initials: G
authors.lastname: Agegnehu
authors.affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Science Road, Richmond, New South Wales 2753, Australia.
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Bass
authors.affiliation: College of Science, Technology and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, PO Box 6811, Cairns, Queensland 4870, Australia.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Nelson
authors.affiliation: College of Science, Technology and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, PO Box 6811, Cairns, Queensland 4870, Australia.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Bird
mesh_terms: D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D018533:Biomass; D002606:Charcoal; D005308:Fertilizers; D017752:Greenhouse Effect; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D018515:Plant Leaves; D012987:Soil / Q000737:chemistry*; D014329:Tropical Climate; D003313:Zea mays / Q000254:growth & development*
chemical_list: D000393:Air Pollutants; D005308:Fertilizers; D009566:Nitrates; D012987:Soil; C540010:biochar; D002606:Charcoal; D010758:Phosphorus; D009584:Nitrogen
keywords: Biochar; Co-composted biochar–compost; Compost; Ferralsol; Greenhouse gas fluxes; Soil quality