Hot Water Extractable Soil Carbohydrate - A Sensitive Measurement for Determining the Impact of Long-term Tillage and Residue Management

A long-term field experiment was established in 1982 at the University of Plymouth Farm, Seale-Hayne, Devon, South West England to assess the impact of contrasting tillage and residue management on the agronomy of winter wheat (Triticum aestivum L.). Using this pre-established trial site, we investigated the long-term impact of tillage and residue management on hot water extractable soil carbohydrate (HWC) and predicting its usefulness as indicator of soil quality. Tillage and residue management significantly affected concentration and depth-wise distribution of HWC in soil. The HWC showed promise in differentiating tillage systems and residue management practices in affecting the HWC concentration in soil. The HWC showed significant positive correlation (R² = 0.65, P<0.001) with microbial biomass carbon (MBC) and activity of acid phosphatase (R² = 0.76, P<0.001) and β-glucosidase enzyme (R² = 0.93, P<0.001) in soil but showed significant negative correlation with bulk density (R² = 0.44, P<0.001) and soil pH (R² = 0.44, P<0.001). Given strong correlation with MBC and activity of acid phosphatase and β-glucosidase enzymes, it appears that HWC could be used as a sensitive indicator of soil quality.