Arbuscular mycorrhizal fungi (AMF) improves the uptake of nutrients and water to the plants through mutual symbiosis. Only AMF produces glomalin related soil protein (GRSP). Acaulospora morroaiae, Glomus luteum, Glomus verruculosum, Glomus versiforme are the effective glomalin producing AMFs. Mixed primary forest, tropical rainforest, soil organic matter, clay soil, no tillage, quality and quantity of fertilizers, crop rotation, and water stable aggregates are also suitable to increase glomalin production. Glomalin is a glycoprotein that contains 30–40% carbon (C) which is assumed to be stable and persistent in soil. The glomalin can sequestrate more carbon in the soil due to its high carbon and aggregate stability. Greater aggregate stability leads to high organic carbon protection in terrestrial ecosystems. The lowest glomalin content (0.007 mg per gram soil) was found in Antarctic region, and the highest glomalin content (13.50 mg per gram soil) was observed in tropical rainforest. In agricultural soil, glomalin content varies between 0.30 and 0.70 mg per gram soil. The GRSP containing soil organic carbon (SOC) in deeper soil layers was 1.34 to 1.50 times higher than in surface layers. Glomalin can sequestrate 0.24 Mg C ha-1 in soil when present at 1.10±0.04 mg g-1. At elevated CO2 (700 µmol mol-1) level, easily extractable glomalin (EEG) and total glomalin (TG) were 2.76 and 5.67% SOC in the surface soil layer over ambient carbon dioxide (CO2) level. This finding indicates the effective function of GRSP C sequestration in soil under global environmental change scenarios. Glomalin can also protect labile carbon that can help regulating nutrient supply to the plants. No tillage practice causes higher AMF hyphal length, GRSP and water stable aggregate (WSA) compared to that of conventional tillage practice. The current review demonstrated that GRSP is an important tool for carbon storage in deep soils. Glomalin mediates soil aggregates, improves soil quality, increases carbon sequestration and crop production, and mitigates climate change.

In search for an efficient means of building up the carbon stock, improving the fertility levels and aggregate stability of tropical soils for optimum crop yield, a field study was carried using different biochars and comparing the effects with inorganic fertilizer. The biochars were palm bunch biochar (PBB), saw dust biochar (SDM) and rice mill husk biochar (RMHB). Treatments consisted of 10 t/ha palm bunch biochar + 0.25t/ha poultry manure (T1), 10 t/ha rice mill husk biochar + 0.25t/ha poultry manure (T2), 10 t/ha saw dust biochar + 0.25t/ha poultry manure (T3), 500kg/ha N.P.K 15:15:15 fertilizer + 0.25t/ha poultry manure (T4) and plot without biochar + 0.25t/ha poultry manure (T5) (control plot). These were replicated five times on experimental plots of 4m2 in a randomized complete block design. Maize (Zea mays) was used as a test crop and data obtained were statistically analyzed using analysis of variance and correlation. Soils amended with biochars significantly improved soil pH, organic carbon, exchangeable bases and base saturation than non biochar fertilized soils. Saw dust biochar increased soil carbon stock by 95.1% against NPK fertilizer plots and control. There was 19% decrease in soil bulk density and 17% increase in soil pH with application of palm bunch biochar. Amending soils with palm bunch biochar increased soil organic carbon by 51.5%. The biochars increased the values of critical level of soil organic matter, modifies clay ratio and reduced the value of clay flocculation index more than NPK fertilized soils or control. Among the treatments, rice mill husk biochar recorded the highest maize cob weight though not significant with palm bunch biochar. Therefore, applying biochars on eroded soil is an effective measure of improving the stability, soil carbon stock as well as enhancing higher maize yield than inorganic fertilizer.