PS 17-136
Lawn management effects on soil carbon quality
Large intra-annual changes in soil C pools have been observed under turfgrass lawns, and lawns have been observed to substantially increase soil C pools under certain conditions. In order to better understand these dynamics and determine any influence that lawn management might have on them, we conducted long-term (90+ days) incubations of soil collected from under tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) managed to mimic a range of observed homeowner behaviors at several points throughout the growing season. We used a three-pool model to generate estimates of fast-turnover, slow-turnover, and recalcitrant soil C pools.
Results/Conclusions
Differences in total soil C pools between sampling dates were larger than differences between management treatments, suggesting that a general pattern of rapid soil C accumulation in the spring, followed by gradual depletion over the course of the growing season dominates intra-annual dynamics. However, each of our management variables (mowing height, irrigation, and fertilization) had significant (α=0.05) effects on the size of different soil C pools at different points in time, indicating that management can influence how C is processed in this system. The ratio of fast-turnover to slow-turnover to recalcitrant soil C in this system appears to be weighted more heavily toward fast-turnover C than in other systems where this has been measured.