Effect of Manure and Vermicompost Applications on Micromorphological Properties of a Sandy Loam Soil

Micromorphological observations on aggregates size, pores and their distribution can provide precise expression of soil structure and simplify the interpretation of soil behavior. This research aim was to study the effect of two natural organic conditioners (vermicompost and manure) on soil micromorphological characteristics such as pore and aggregates size distributions, total porosity and microstructure in a sandy loam soil. In this study it was assumed that the aggregation and porosity increase due to reduction in macro and micropores portion with respect to mesopores in soil, and the structure of the soil improves comparing with the control treatment. Soil sampling has been done by Kubina boxes (3×4×6 cm) in 0-30 centimeters of topsoil of soil columns treated by two conditioners and incubated during 30 or 180 days at 0.75Fc. All samples were impregnated with resin and hardener after drying and then thin sections were prepared and finally studied with polarizing microscope. Based on the obtained results, structure development by both conditioners especially at the second application rate (5 & 25 g/kg dry soil for vermicompost and manure, respectively) and 180 days of incubation was observed that had remarkable effect on aggregation and caused large and highly developed aggregates. Both organic conditioners increased meso and macropores conspicuously at the second application rate and 180 days of incubation.