Response of soil physicochemical and microbial properties to organic amendment addition in three soil types

ABSTRACT Conventional agricultural practices have progressively reduced soil fertility, largely as a consequence of C depletion. So, the application of organic amendments as a fertilization strategy should enhance soil properties and promote long-term sustainability. This study assessed the effects of a composted organic amendment, “bio-stabilized”, as improver of the soil properties applied at rates of 1% and 2% (w/w), on the chemical, physical, and microbiological properties of three soils with contrasting textures (sandy loam, silt loam, and clay loam) following a 30 d aerobic incubation. The results showed that bio-stabilized application improved chemical properties across all soils, resulting in agronomically adequate nutrient availability and acceptable electrical conductivity levels (< 0.55 dS m-1). In addition, water retention increased at potentials corresponding to different pore-size classes in two soils (500-1500 kPa in the silt loam soil and 33-1500 kPa in the clay loam soil). Microbiological properties increased quantitatively with bio-stabilized application; however, a significant increase in dissolved organic C was observed only in the clay loam soil (from 98.4 to 283.4 mg kg-1). Overall, the application of bio-stabilized at the evaluated rates improved soil properties, with positive implications for agronomic performance and soil sustainability.