Soil management and environmental sustainability of crop-livestock systems

Abstract

Uruguay experienced an expansion of the cropped area in the last decades motivated by market conditions: price of grains, differences in the relative land value, and regional tax policies. This change affected the crop-livestock production system, mainly in soil quality and system sustainability. The available information on soil erosion and organic carbon content (soc) allowed to validate the models usle/rusle and century, which demonstrated the advantages of crop-pasture rotations compared to continuous cropping. No-till represented an outstanding advance, by reducing mechanical tillage. The drop in soil organic carbon was correlated with a productivity decrease, mainly due to the lower availability of nutrients and limitations in the physical properties of the soil. The Global Soil Alliance of fao highlights the three most important threats on sustainable soil management: erosion, loss of organic carbon, and nutrient imbalance. The main public policy in Uruguay is the application of the Law of Soil and Surface Water Conservation. The principal measure is that cropping cannot present erosion estimates above the official tolerance for the dominant soil used. It became mandatory in 2013, and currently, 96% of the obliged area has complied with the presentation of the plans, covering 1.6 Mha. In 2018, a proposal for the Environmental Plan for Sustainable Development based on agroecology elements was generated from the Environmental Ministerial Office. Crop-pasture rotations include varied plant and animal production, and comply with most agroecology elements, minimizing erosion and maintaining or recovering soc.