An online system for calculating and delivering long-term carrying capacity information for Queensland grazing properties. Part 2: modelling and outputs

Abstract

A combination of field data and models have been used to estimate long-term carrying capacity (LTCC) of domestic livestock in Queensland grazing lands. These methods have been synthesised and coupled with recent developments in science and information technology to provide a fully-automated approach of modelling LTCC through the FORAGE online system. In this study, the GRASP model was used to simulate pasture growth with parameter sets and safe pasture utilisation rates defined for 225 land types across Queensland. Distance to water points was used to assess the accessibility of pastures to livestock. Spatial analysis classified the property into unique areas based on paddock, land type and distance to water points, which estimated pasture growth, pasture utilisation and accessibility at a sub-paddock scale. Thirteen foliage projective cover (FPC) classes were used in modelling the pasture system to deal with the non-linear relationship between tree and grass interactions. As 'proof of concept', remotely-sensed individual-date green ground cover data were used to optimise the GRASP model parameters to improve the model performance, and a Monte Carlo analysis provided uncertainty estimates for model outcomes. The framework provides an efficient and standardised method for estimating LTCC. To test the system, LTCCs from 43 'benchmark' properties were compared with simulated LTCCs, and 65% of the modelled LTCCs were within AE 25% of the benchmark LTCCs. Due to uncertainties in model inputs at the property scale and in model simulation, the modelled LTCC should be used as a starting point for further refinement of actual property LTCC.

Improving Human Diets and Welfare through Using Herbivore-Based Foods: 1. Human and Animal Perspectives

“…The rangelands have suffered a series of severe droughts over the past hundred years, leading to episodic overstocking and subsequent depletion of browse vegetation leading to increased soil erosion, dominance of woody species, and decline in forage availability [140]. In response, the concept of a 'safe', or long term, livestock carrying capacity (LTCC) has been developed [141,142] to ensure the pasture resource could be sustained for 30 years or more under the pressure of decadal variation in rainfall. The LTCC is defined as "the number of animals (e.g., dry sheep equivalents or beef equivalents) that can be carried on a land system, paddock or property without any decrease in pasture condition and without accelerated soil erosion" [143].…”

“…The experience of graziers themselves in dealing with drought was incorporated in the development of the concept. In Queensland, graziers can now access property-specific information from the online system FORAGE [144] which draws data from spatial datasets of climate, soils, woody vegetation cover, and satellite-derived ground cover [141,142,145]. The FORAGE tool is a culmination of the "comprehensive synthesis of the advances in grazing land sciences and modelling over the last couple of decades", [142] and a good example of the potential to implement practical solutions based on sound science made accessible to all end users via the internet.…”

An integrated pasture biomass and beef cattle liveweight predictive model under weather forecast uncertainty: An application to Northern Australia

“…These models were chosen because of their direct relevance to liveweight production, and also because they have been previously applied within the agricultural context of Northern Australia, where the case studies of this current article are situated. This model is considered to be adequate for the given local conditions and the natural native pastures that grow in the region (Carter et al, 2000; Day et al, 1997; Zhang et al, 2021).…”