Potential of established pastures in the winter rainfall region.

Abstract

The seasonal production of 11 pastures was evaluated in

dryland and irrigated trials at eight sites in the Winter

Rainfall Region. These data were related to climatic

conditions using the Growth Index concept to produce a model

for pasture growth.

Under dryland at Tygerhoek, the animal production potential

of lucerne and medic was compared in grazing trials.

Lucerne was found to be the higher producing of the two. At

this site also, the influence of chemical control of

volunteer grasses in dryland pastures on animal production

potential was tested. Weed control had a positive influence

on animal production at low, but not at high stocking rates.

Under irrigation at

complex grass/legume

Tygerhoek, the grazing capacity of a

mixture was established under continuous

and rotational grazing. While rotationally grazed

pastures produced the highest yields, the clover component

of these pastures proved to be most productive under

continuous grazing. As a result, rotationally grazed

pastures, could carry more animals, but animal production

was generally highest under continuous grazing.

Under irrigation at Outeniqua, seven grass and grass/legume

mixtures were compared in grazing trials. Pastures based on fescue generally had the highest grazing capacity, but those

based on white clover the highest animal production

potential.

These data were used to produce a climate:pasture:animal

which was validated using independent

This model was used to predict animal

production model,

grazing trial data.

performance of two-species mixtures at a number of sites.

These results suggested that while grass pastures allowed

more animals to be carried than did mixtures, both animal

performance and gross returns were highest in grass/legume

mixtures.