Spelling strategies for recovery of pasture condition

Abstract

This project seeks to improve the evidence base and modelling capacity underpinning recommendations for the use of wet season spelling to recover poor condition grazing land and design more reliable and cost-effective spelling options for producers across northern Australia. Our research now has four years of information from the Monteagle site near Clermont, and two years from the Wambiana site south of Charters Towers. Spelling has produced a small, yet significant improvement in perennial grass basal area at Monteagle when compared to grazing at a moderate stocking rate. This improvement is too small to alter a land condition rating, but does demonstrate the beneficial processes fostered by spelling. Lack of a sizeable germinable seed bank for the key perennial grass Bothriochloa ewartiana underpins a lack of its seedlings establishing and is therefore a major contributor to the lack of demonstrable land condition improvement. Both sites have a large amount of Aristida spp. in the pasture which may possibly be reduced by controlled burning to assist land condition improvement. Since spelling began, Monteagle has had two years of very good rainfall, followed by two very dry years while the Wambiana site has had one average, and one below average rainfall year. The Monteagle site was destocked over the 2012/13 summer following a wildfire in November 2012 and then very dry conditions. At Wambiana, the research is conducted under a moderate, or a high stocking rate. Data from the trials will be used to improve the capacity of GRASP to simulate the impacts of different spelling and stocking rate regimes on pasture conditions over a range of pasture community types and seasons. Spelling to improve land condition will often take more years than originally thought and must be in synergy with other best management practices.