Decomposition of Gliricidia Leaves: The Effect of Particle Size of Leaves and Soil Texture on Carbon Mineralization

Crop residues, as a reliable source of nutrients in many agro-ecosystems could minimize the dependency on commercial fertilizers. The particle size of crop residues is a matter of concern as it determines the accessibility of the substrate and nutrients in them to microbial attack. The present laboratory investigation was conducted to elucidate the effect of particle size of Gliricidia leaves (S₁ ≤ 0.5 mm, S₂ = 4 mm) and texture of soil (T₁ = Sandy clay loam, T₂ = Loamy sand) on decomposition. The highest C mineralization in Sandy clay loam soil and Loamy sand soil treated with the particle size of ≤ 0.5 mm were 134 and 241 mg/kg soil respectively. The corresponding figures for the particle size of 4 mm were 130 and 218 mg/kg soil respectively for Sandy clay loam soil and Loamy sand soil. Finer particles (≤ 0.5 mm) have shown significantly higher C mineralization than that of in coarse particles (4 mm) through-out the incubation except at day 2, 7 and 14. Furthermore, C mineralization in Loamy sand soil was significantly higher than that of in Sandy clay loam soil throughout the incubation. It could be concluded that C mineralization was significantly influenced by the texture of soil as well as the particle size of the plant residues.

Key words: Plant residues; Decomposition; C mineralization; Soil texture

DOI: http://dx.doi.org/10.4038/tare.v13i1.3133

Tropical Agricultural Research and Extension 13(1) 2010 pp.19-23