Soil quality indicator properties in mid-Atlantic soils as influenced by conservation management

ABSTRACT:

Soil quality or condition is best assessed by soil properties that are neither so permanent as to be insensitive to management, nor so easily changeable as to give little indication of long-term alterations. Thirteen such intermediate properties were evaluated for potential inclusion in a soil quality index by comparing soils under contrasting management system from long-term replicated field experiments and from paired field sites. Conservation (v. conventional) management was defined as some combination of reduced tillage, increased crop diversity more perennial crops, increased crop residue return, increased soil fertility and/or increased application of organic amendments. Conservation management most consistently and markedly influenced soil quality indicator properties by increasing total and active microbial biomass carbon (G_TMB and C_AMB, increasing the ratio of active microbial biomass carbon to total organic carbon (C_AMB/C_ORG), increasing aggregation and decreasing the rate of basal respiration per unit of microbial biomass carbon (qCO₂) . The qCO₂ increased exponentially as C_TMB decreased. This may indicate reduced stress on soil microbial communities under conservation management and high microbial populations.