Get reliable rangeland science

In Australia, land degradation caused by wind erosion and dust storms often occur during drought when vegetation cover is low. Destocking early is a critical management action that can reduce soil erosion; however, predicting drought to inform producer decisions regarding destocking is a complicated task. In Australia, drought is determined by several indicators, such as rainfall deficiencies, soil water, pasture growth, water availability, agricultural production, and community impact. Many of these indica tors influence total vegetation cover (denoted as cover), which includes photosynthetic and non-photosynthetic cover. This study uses a 22-year record (2001-2022) to investigate if a "trigger point", i.e., the month and cover level, can be identified that would potentially inform destocking four to six months before a drought cover (<20th percentile minimum monthly cover in summer) is reached. Twenty-four properties in western NSW rangelands were evaluated to determine the trigger month and trigger cover. The trigger month was August for 83% of properties. The drought cover ranged from 60% to 25%. The trigger cover ranged from 70% to 35%. Over the 22 years, 22% of years recorded drought cover. The method correctly predicted 80% of years with drought cover, i.e. those years below the trigger cover that had drought cover the following summer. The method failed to predict drought in six percent of years. In six percent of years, it predicted drought, but no drought occurred. The study demonstrate s the practical application of a new tool to help land managers prepare for drought.