Fertilization of Cool-Season Grasses

Deriving seasonally optimal nitrogen fertilization rates for a ryegrass pasture based on agricultural production systems simulator modelling with a refined AgPasture model

“…This annual rate is in line with observations which have shown linear responses in pasture yield to annual application rates of up to 200–400 kg N ha −1 (Whitehead, ). When N application rates exceed 500 kg ha −1 , yield decreases have been observed due to thinning and increased competition between plants (Wedin, ).…”

Nitrogen use efficiency of legume-grass and grass pastures

“…Cool-season perennial grasses generally require large amounts of N fertilizer to attain maximum yields, although economic N input levels may be less than that level giving maximum yield (Wedin, 1974). Dry matter productivity generally responds linearly to N fertilizer up to levels between 200 to 300 kg/ha (Reed, 1981), with the response sometimes being higher with split applications (Whitehead, 1970).…”

“…The periods of greatest response to N fertilizer in cool-season grasses correspond to the seasons of highest growth rate (Wedin, 1974), presum ably because N demands are also highest then (Andrew and Johansen, 1978). In most species this occurs in spring and early summer (Wedin, 1974). Tall fescue exhibits an additional period of higher growth rate and response to N in the fall compared to smooth bromegrass, orchardgrass and reed canarygrass (Wedin et al, 1966).…”

Effects of nitrogen and cutting management on root growth and productivity of a Kentucky bluegrass (Poa pratensis L.) and white clover (Trifolium repens L.) pasture

“…The timing of N applications can be very important. Wedin (1974) states that cool-season grasses fertilized before the cool season starts have a very high N use efficiency. In this experiment N fertilizer was applied in early June, when Kentucky bluegrass has already reached its growth peak, and in late August, before the usual fall increase.…”