The Uruguayan rice-livestock system is one of the most productive worldwide, adding meagre amounts of N as fertiliser and reaching a very tight nitrogen (N) balance (N-BAL), low N surplus (N-SUR) and a high system N use efficiency (NUE), being a good example of a circular economy system.

ABSTRACT.- The UK Government has set an ambitious target of achieving a national "net-zero" greenhouse gas economy by 2050. Agriculture is arguably placed at the heart of achieving net zero, as it plays a unique role as both a producer of GHG emissions and a sector that has the capacity via land use to capture carbon (C) when managed appropriately, thus reducing the concentration of carbon dioxide (CO2) in the atmosphere.

Sustainability of water quality and quantity in Merín Lagoon (ML) basin has become an issue of concern, recognizing nutrient runoff from agricultural environment as one of the major sources influencing water impairment. The main area of rice cultivation in Uruguay is located in this watershed.

Integrated rice-livestock systems were key for a sustained yield increase with decent resource-use efficiency and environmental indicators during 50 yrs. in Uruguay. The increased trends for intensification in cropping systems may prompt rice-livestock systems for decoupling and losing synergies. We summarize evidence about the sustainability of rice-livestock systems in Uruguay using indicators from farm data and a long-term experiment.

The aims of this study were to assess the long-term effects of different CPR on SOC stocks on the subsoil, and to draw conclusions about the capacity of CPR to sequester C in Uruguay.We conclude that incorporating pastures in continuous crop sequences increased soil organic carbon stocks through the soil profile by an average of 28%.

Soil organic carbon (SOC) sequestration is key in mitigating climate change. Rice systems rotated with perennial pastures are being intensified in South America to increase annual grain productivity, but the effects on SOC and rice yield remain poorly understood. These results highlight insights for the design of rice-based rotations that increase or sustain SOC and increase rice yield, helping simultaneously meet climate change and food production goals.