A wide range of responses have been reported to winter cleaning. The variability can be explained by the initial weed infestation, soil and climatic conditions, timing and rate of herbicide application, other species present in the pasture and post-spraying grazing management. Below is a summary of results of numerous trials:
- Winter cleaning will result in a reduction in winter production in the year of application. The impact is greater when annual grasses are dominant and spraying is delayed. Suppression of sub-clover and grasses can occur. Losses in dry matter can be as large as 50% for up to eight weeks (Dear et al., 1992), (Sandral and Dear, 2005), (Keys et al., 1990).
- The contribution of desirable species to overall production will increase in the long term, leading to more high quality feed and longer seasonal growth (Keys et al., 1990), (Nichols, 2000).
- More sub-clover will germinate in following years because of the removal of the allelopathic toxins which leach out of dry silver grass, reducing germination and seedling growth in sub-clover (An, 1997).
- The benefits from winter cleaning can be seen for five years or more (Nichols, 2000).