Domestic Herbivores, the Crucial Trophic Level for Sustainable Agriculture: Avenues for Reconnecting Livestock to Cropping Systems

Abstract

Domestic herbivores have been closely associated with the historical evolution and development of agriculture systems worldwide as a complementary system for providing milk, meat, wool, leather, and animal power. However, their major role was to enhance and maintain agricultural soil fertility through the recycling of nutrients. In turn, cereal production increased, enabling to feed a progressively increasing human population living in expanding urban areas. Further, digestion of organic matter through the rumen microbiome can also be viewed as enhancing the soil microbiome activity. In particular, when animal droppings are deposited directly in grazing areas or applied to fields as manure, the mineralization–immobilization turnover determines the availability of nitrogen, phosphorus, potassium, and other nutrients in the plant rhizosphere. Recently, this close coupling between livestock production and cereal cropping systems has been disrupted as a consequence of the tremendous use of industrial mineral fertilizers. The intensification of production within these separate and disconnected systems has resulted in huge emissions of nitrogen (N) to the environment and a dramatic deterioration in the quality of soil, air, and ground- and surface water. Consequently, to reduce drastically the dependency of modern and intensified agriculture on the massive use of N and phosphorus (P) fertilizers, we argue that a close reconnection at the local scale, of herbivore livestock production systems with cereal-based cropping systems, would help farmers to maintain and recover the fertility of their soils. This would result in more diverse agricultural landscapes including, besides cereals, grasslands as well as forage and grain crops with a higher proportion of legume species. We developed two examples showing such a beneficial reconnection through (i) an agro-ecological scenario with profound agricultural structural changes on a European scale, and (ii) typical Brazilian integrated crop–livestock systems (ICLS). On the whole, despite domestic herbivores emit methane (CH4), an important greenhouse gas, they participate to nutrient recycling, which can be viewed as a solution to maintaining long-term soil fertility in agro-ecosystems; at a moderate stocking density, ecosystem services provided by ruminants would be greater than the adverse effect of greenhouse gas (GHG).

Cattle dry manure fertilization increases forage yield of grass‐legume mixtures, while maintaining the legume proportion and root‐associated microbiota

“…Organic amendments derived from livestock systems (e.g. manure), as other sources of nutrients, should be reconsidered to maintain long‐term soil fertility in agroecosystems (Lemaire et al, 2023). Manure, as an organic amendment, enhances the properties of soil by providing nutrients, organic matter (OM), and microorganisms (Flavel & Murphy, 2006; Lynch et al, 2013; Ozlu & Kumar, 2018; Paul & Beauchamp, 1996).…”

Impact of beef cattle on eucalyptus trees in a silvopastoral system

“…Such systems combine valuable elements in food production systems because they are strategically designed to maximize synergy by mimicking the natural environment (Lemaire et al, 2014). In the face of climate change and food insecurity, the diversi cation of production systems through the use of ICLS represents an important alternative for the sustainable intensi cation of land use (Lemaire et al, 2023), as well as to avoid the opening of new agricultural frontiers (Strassburg et al, 2014). Silvopastoral systems, a modality of ICLS, have been shown to act as a sink for greenhouse gases (Morales et al, 2023).…”

Understanding the changes induced by the incorporation of trees in low densities into livestock systems: relevance of a long-term interdisciplinary experimental platform

“…However, the adoption of highly productive models characterized by monoculture and the intensive use of fertilizers and herbicides has had detrimental effects on land stability, water, and the environmental and natural resources (Lemaire et al, 2023). The urgent demand to address these challenges necessitates the generation of knowledge that fosters the development of sustainable production systems.…”