Spelling strategies for recovery of poor land condition

Abstract

Pasture condition has declined across many pasture communities across northern Australia. Pasture spelling is a key recommendation for the recovery of land condition but there is limited information on the optimum length and frequency of spelling or the recovery rates possible under different spelling and stocking rate combinations. This 12-year study examined the effects of early and full wet season spelling applied annually or biennially, on the recovery of poor condition land and the demography of the key perennial grass, Bothriochloa ewartiana, under heavy and moderate stocking rates. The study period was characterised by low rainfall and extreme drought conditions in some years. Average basal cover of perennial species declined with the onset of dry years with the effects of drought amplified under heavy stocking. Basal cover later increased as conditions improved but cover under heavy stocking never recovered to that under moderate stocking. Annual early and full wet season spelling under moderate stocking had a positive effect on the basal cover of B. ewartiana but this effect was only significant (P < 0.03) after 12 years. Spelling had no effect on basal cover under heavy stocking, emphasising the overriding effect of stocking rate on recovery. Basal cover through the drought was largely maintained through the persistence of original tussocks, emphasising the importance of maintaining established plants through good management. In later years, an increasing number of recruits also increased basal cover. Land condition can be improved with annual wet season spelling provided stocking rates are appropriate, but recovery can initially be slow, particularly through dry years. These results emphasise the key role that spelling has in maintaining and improving pasture condition.