Long term tillage, cover crop, and fertilization effects on microbial community structure, activity: Implications for soil quality

Abstract Conservation agriculture practices, such as reduced tillage, cover crops and fertilization, are often associated with greater microbial biomass and activity that are linked to improvements in soil quality. This study characterized the impact of long term (31 years) tillage (till and no-till), cover crops (Hairy vetch - Vicia villosa and winter wheat- Triticum aestivum , and a no cover control), and N-rates (0, 34, 67 and 101 kg N ha −1 ) on soil microbial community structure, activity and resultant soil quality calculated using the soil management assessment framework (SMAF) scoring index under continuous cotton ( Gossypium hirsutum) production on a Lexington silt loam in West Tennessee. No-till treatments were characterized by a significantly greater (P  Consequently, the total organic carbon (TOC) and β-glucosidase SMAF quality scores were significantly greater under no-till compared to till and under the vetch compared to wheat and no cover treatments, resulting in a significantly greater overall soil quality index (SQI). Our results demonstrate that long-term no-till and use of cover crops under a low biomass monoculture crop production system like cotton results in significant shifts in the microbial community structure, activity, and conditions that favor C, N and P cycling compared to those under conventional tillage practices. These practices also led to increased yields and improved soil quality with no-till having 13% greater yields than till and treatments under vetch having 5% increase in soil quality compared to no cover and wheat.