Economic value of grazing vegetative wheat (Triticum aestivum L.) crops in mixed-farming systems of Western Australia. (Special Issue: Grain & Graze: an innovative triple bottom line approach to collaborative and multidisciplinary mixed-farming systems research, development and extension.)

摘要

Livestock production in Western Australian mixed-farming systems has traditionally been constrained by a profound scarcity of feed in autumn-early winter when crop stubbles and pasture residues from the previous growing season have been exhausted. This study investigates the profitability of partially filling this 'feed gap' through the grazing of vegetative wheat crops. Whole-farm bioeconomic modelling is used to provide insight into the relative value of grazing and grain production in both low- and high-rainfall areas of Western Australia. Dual-purpose wheat crops are a valuable source of feed in high-rainfall areas as they provide an affordable alternative to expensive grain supplements for a short period in winter. This also allows annual pastures to establish more vigorously by reducing grazing pressure on young plants. Model output suggests farm profit can increase by over 10% with the grazing of vegetative wheat crops in high-rainfall regions; however, these results are logically shown to be strongly related to the assumed rate of yield loss. In contrast, at the parameter values used in this study, grazing wheats are unlikely to be profitable in low-rainfall environments due to depressed crop production and the extended feed gap experienced in these areas. Higher grain prices unequivocally lower the relative advantage of grazing activity since this elevates the cost of foregone grain yield.