Sustainable intensification of the world’s agricultural systems is a complex challenge because it requires achieving multiple goals, some of which may be conflicting. This paper provides an excellent case study for that.
In Uruguay, irrigated rice has been grown for many decades in rotation with pasture for grazing by cattle and sheep. This system has resulted in high rice productivity and nutrient use efficiency while it is also considered to be very sustainable. Yet, the pressure has grown to replace the rice-pasture rotation with rotations of rice-soybean or rice grown annually, with cover crops during Winter.
In 2012, INIA researchers established a unique long-term experiment to study the implications of such land use change. Results of the first 7 years are discussed in this paper, using 10 indicators that quantify different aspects of sustainability. The intensification of rice-pasture with annual crops increased system productivity, but also external nutrient and energy inputs. The annual rice-cover crop system had the highest carbon footprint per hectare land area, whereas soil organic carbon increase in rice-pasture offset nearly 50% of the carbon footprint in this system. Gross income was highest in rice-cover crop followed by rice-soybean and rice-pasture. However, gross margin followed the reverse order.
A multi-criteria index showed that the rice-pasture system had the highest level of stability. We learn from this excellent study that (i) it is not easy to achieve a perfect combination of performance and stability across all dimensions of sustainability and (ii) the intensification of rice-pasture with annual crops could reduce the stability of sustainability without actually increasing economic performance significantly.
