Long term effects of different stocking strategies on land condition and profitabilty in a highly variable climate

Abstract

Rainfall variability is a major challenge to sustainable grazing land management in northern Australia. We present data from a long-term grazing trial comparing the performance of different cattle stocking strategies over 27 years of highly variable rainfall. Strategies involved combinations of different stocking rates, fixed versus flexible stocking and wet season pasture spelling. Individual live weight gain (LWG) and product price were highest at moderate stocking rates applied with or without wet season spelling.

Total LWG/ha was highest at heavy stocking rates, but gross margins lowest due to reduced product value and drought feeding costs. Flexible stocking was as profitable as fixed moderate stocking but also avoided the need to destock in drought years.

Land condition as indexed by the proportion of 3P (palatable, perennial and productive) grasses declined rapidly under heavy stocking, reducing resilience and long-term carrying capacity (LTCC). Although fixed moderate stocking at LTCC initially maintained land condition, condition ultimately declined due to the failure to reduce stocking rates in droughts. Land condition also declined with drought under flexible stocking, but recovery appears greater with recent good seasons. Wet season spelling was essential to buffer drought effects and is accelerating recovery post drought.

These results show that over the long term, heavy stocking is a high risk, and ultimately an unprofitable and unsustainable strategy. Although fixed, moderate stocking strategies are lower risk, they will still lead to degradation if stocking rates are not reduced in dry years to match forage availability. We recommend that climate variability be managed using flexible stocking rates in a pro-active, risk averse manner coupled with regular wet season spelling. These should be applied adaptively based on seasonal conditions and observed responses to management actions.