Summary
A grazing trial was conducted to identify environmental and management factors affecting the stability, productivity and profitability of grazing in the southern speargrass lands. The project assessed the effects of four stocking rate regimes (very low, low, medium, high), and legume bandseeding, on the composition and stability of pastures in three land classes, representing the variation occurring in commercial paddocks.
Increased grazing pressure led to the replacement of large, productive perennial grasses (notably Heteropogon contortus) by smaller, short-lived grasses and forbs, perennial forbs, and ultimately by drought-resistant perennials such as Fimbristylis dichotoma and Chrysopogon fallax. Soil changes were associated with the pasture changes, leading to increased rainfall runoff and lowered potential plant productivity. The mid slope land class was relatively resistant to degradation. Other land classes were adversely affected by grazing pressure, but upper and lower slopes were modified by different processes.
