Model of dry matter and plant nitrogen partitioning between leaf and stem for coastal bermudagrass. I. Dependence on harvest interval

Forage production depends on factors such as applied nutrients, available water, and harvest interval (for perennials). It has been shown that seasonal yield of Coastal bermudagrass (Cynodon dactylon L. Pers.) and Pensacola bahiagrass (Paspalum notatum Flugge) are dependent on harvest interval. A growth model has been developed which describes this dependence quite well. This analysis explains the response in terms of partitioning between leaves and stems. It accounts for the strong decrease in leaf dry matter fraction with increase in harvest interval. Data from Tifton, GA for Coastal bermudagrass are used to show that at a harvest interval of 4 wk the leaf fraction is approximately 78%. Peak dry matter production of 20.3 Mg ha(-1) is estimated to occur at a harvest interval of 10.4 wk, with a corresponding leaf fraction of 51%.