بهره وری از زمین استفاده از سیستم گوشت گاو در شمال شرقی ایالات متحده از دیدگاه عرضه مواد غذایی

One widely recognized strategy to meet future food needs is reducing the amount of arable land used to produce livestock feed. Of all livestock products, beef is the largest land user per unit output. Whether beef production results in feed-food competition or a net positive contribution to the food supply, however, may depend largely on whether marginal land is used to grow forage. The land use ratio (LUR) was developed by van Zanten et al. (2016a) to identify livestock systems that produce more animal source food than would be produced by converting their associated feed land to food crop production – a perspective that is not addressed within life cycle assessment (LCA). van Zanten et al. (2016a) used country-specific and farm-level land suitability data, the latter of which is not available in many countries. To assess the LUR of beef systems in the USA, which may use large grassland areas of potentially varying quality across scales, an intermediate approach between farm and country-scale estimation is needed. In this paper, we enhanced the LUR by integrating geospatial data for crop suitability and yield estimation at multiple scales. By doing so, the LUR will also become more widely applicable for other studies. We applied our enhanced LUR for a grass-fed beef (GF) system and a dairy beef (DB) system in the Northeastern USA, including multiple scenarios limiting land conversion. All systems had LURs greater than one, indicating they produce less protein than conversion of their suitable feed land base to food cropping would. Because a large fraction of the forage land used in the GF system was suitable for crop production and moderately productive, its LUR was 3–6 times larger (less efficient land use from a food supply perspective) than the DB system. Future research should explore mechanisms to reduce the LUR and life cycle environmental burdens of both regional production systems.