Reconsidering the land resource for food production: quantifying feed-food competition in dairy systems

Purpose
Land used in agricultural production provides different services and causes various impacts. The potential of the land resource to produce biomass can e.g. be reflected by exergy-based methods using net primary productivity indicators. However, the potential to produce food, feed, fuel and fibres is currently not considered by common resource indicators. In this study, indicators for quantifying the feed-food competition in animal production in terms of energy and protein supply for human consumption were used.
Methods
The food-competition indicator reflects the direct competition and quantifies human edible protein and energy contained in the feedstuffs used in relation to the milk and meat produced. The land-competition indicator refers to the indirect competition for land use, and quantifies the potential of the land used to produce protein and energy for human nutrition by food crops relative to human edible proteins and energy from milk and meat. Protein quality (using the DIAAS method) was systematically taken into account for both indicators. They were applied to 25 Swiss dairy farms.
Results
The food-competition indicator (0.01-0.54 for protein, and 0.03-0.68 for energy) showed a low direct competition. There was a strong correlation with the use of concentrates per unit of milk. The use of by-products from food and feed production led to lower food competition. The land-competition indicator showed a strong competition in most cases (0.69-2.64 for protein, and 1.52-5.93 for energy). Only two farms had an indicator value of <1 for protein. Determining factors were the arable land area, its yield potential, and milk-production efficiency parameters (feed utilisation, restocking rate). Both indicators showed lower competition with regard to protein than with regard to energy, as the protein quality in animal products is rated higher than that of the protein in food crops.
Conclusions
The food-competition and land-competition indicators describe different aspects of competition and do not correlate. The combination of indicators helps to assess feed-food competition in a comprehensive way. Furthermore, the land-competition indicator can be used in agricultural LCA studies to describe the food production potential of the land occupied.