WHAT IS THE MAKE-UP OF A DRYLAND PASTURE?

Abstract

Summer grazing managements, spelling, set-stocking, fast or slow rotations and topping or no topping, did not influence herbage growth in autumn of Nui ryegrass pasture. The cause of pasture deterioration on dryland, previously suggested to be through summer overgrazing, now seems more likely to be an effect of autumn overgrazing, particularly if pastures have been attacked by Argentine stem weevil and drought is continuing from summer. Low nitrogen fertility through often low fixation of nitrogen by clover, uncertainty of response of pasture to nitrogen fertiliser in cool season, and the effects from overgrazing, cause an extreme limitation in autumn-winter feed supply for stock in drought years. Feeding of silage in summer-autumn is advocated as a positive approach to this situation. On sunny aspects of dry hill country, buildup of dead herbage through summer considerably reduces the quality of the subsequent cool season growth of grass in the herbage mass. Several attempts to establish oversown grasses for improved cool season yield have not been successful. Dry hill grassland thus provides a considerable challenge to effect much improvement beyond manipulating the quality of the existing vegetation by grazing management. Keywords: Dryland pasture, grazing management, fertility, herbage quality