The Effect of Turfgrass Species Litter on Soil Microbial Activity and Aggregate Stability.

Turfgrass litter quality affects microbial activity and changes in organic matter mineralization.  However, the variation in litter quality varies across turfgrass species and the microbial response to these changes is not well understood. Therefore, the objectives of this research were to quantify 1) the soil microbial activity response and 2) changes in soil aggregate stability to the introduction of five turfgrass species residues.  A total of 0.2 g of leaf and stem litter from 5 turfgrass species, bermudagrass (Cynodon dactylon), creeping bentgrass (Agrostis stolonifera), Kentucky bluegrass (Poa pratensis), tall fescue (Schedonorus arundinaceus), and zoysiagrass (Zoysia japonica), were added to 473 mL canning jars containing 25 g of a Clermont silt loam soil.  Microbial activity was measured via CO₂ evolved using the alkali trap method. Turfgrass leaf and stem lignin, cellulose, hemicellulose, ninhydrin-N, total carbohydrate, and total phenolic acid contents were used to differentiate litter effects on aggregate stability. Turfgrass species significantly affected microbial activity for rate of CO₂ evolved.  Preliminary turfgrass litter quality effects on aggregate stability will be discussed.