Ar. Overman et Dl. Robinson, COUPLING OF DRY-MATTER AND NITROGEN ACCUMULATION IN MILLET AND RYEGRASS, Communications in soil science and plant analysis, 28(3-5), 1997, pp. 217-224
The logistic model has proven very useful in relating dry matter produ
ction of warm-season and cool-season forage grasses to applied nitroge
n (N). A recent extension of the model coupled dry matter and plant N
accumulation through a common response coefficient c. The objective of
this analysis was to apply the extended model to both warm season pea
rl millet [Pennisetum typhoides (Burm.) Staph and C. E. Hubb.] and coo
l season ryegrass [Lolium multiflorum Lam.], and to establish a common
response coefficient, c, between accumulation of dry matter and plant
N for the two grasses in rotation. Analysis of variance established t
he validity of this hypothesis. The model accurately described respons
e of dry matter, plant N removal, and plant N concentration to applied
N, with an overall correlation coefficient of 0.9954. Furthermore, th
e model closely described the relationship between yield and plant N r
emoval. The logistic equation is well behaved and simple to use on a p
ocket calculator. It can be used to estimate yield and plant N removal
in evaluation of agricultural practices and the influences on environ
mental quality.