Accumulation of dry matter and plant nutrients by perennial grass over
the growing season is dependent upon harvest interval and availabilit
y of water and applied nutrients. Mathematical models are frequently i
ncorporated in the analysis, design, and operation of systems for land
application of reclaimed water (municipal or agricultural). The objec
tive of the present work was to measure response of warm-season Coasta
l bermudagrass [Cynodon dactylon (L.)] to irrigation with reclaimed mu
nicipal wastewater and to evaluate parameters for a simplified model.
Grass was harvested at intervals of 2, 4, and 6 wk. Measurements inclu
ded yields (dry matter and digestible organic matter) and plant nutrie
nt uptake (N, P, and K). The probability model described time trends r
ather well. The linear model parameter A showed linear dependence on h
arvest interval Delta t over the range studied, in agreement with resu
lts from the literature. Maximum values for a harvest interval of 6 wk
were 16.5 Mg ha(-1) (dry matter), 8.0 Mg ha(-1) (digestible organic m
atter), 350 kg N ha(-1) 57 kg P ha(-1), and 272 kg K ha(-1).