Sloping agricultural land is, anywhere in the world, subject to soil erosion and it has long been established that this also leads to significant nutrient losses. While it is relatively easy to compensate for the on-site effect of these losses in the context of intensive agriculture the magnitude of these losses at a continental/global scale is economically very significant. Furthermore, nutrient losses have detrimental effects on aquatic environments downstream of agricultural land. In this paper I briefly revise the magnitude of nutrient losses from agricultural land and their implications but my main focus is on the development of a vision on how these losses can be reduced, which is a prerequisite for the development of a sustainable agricultural system.
While the necessary agricultural technology to reduce erosion to near-natural levels on agricultural land does exist, it is also clear that simply promoting the application of measures such as conservation agriculture is not sufficient, as the uptake of these techniques by farmers often remains limited. Reducing nutrient losses from erosion cannot only be achieved through erosion control at the field scale, however. Two key observations are important here : (i) Soil loss is generally most important on steep slopes and (ii) agricultural yields are generally lower on sloping land. Thus, erosion at the regional/continental scale can be greatly reduced by setting aside the steepest land and concentrating arable crops in the flatter areas. Also within Europe there is considerable scope for such an approach as, in many regions, yields are still well below what is attainable. It is therefore possible to achieve the same agricultural output while using significantly less arable land.
Adapting such an approach will not solve all erosion problems as some erosion-prone land use, such as vineyards, cannot be simply moved to flatter land. Effective erosion control will therefore require a general implementation of soil conservation technology in combination with the intensification of arable production on the best suited arable land while setting aside erosion-prone land. By doing so, we will reap important additional benefits in terms of soil carbon storage, water use efficiency and biodiversity conservation because the spared arable land can be used for other purposes, such as nature conservation. Indeed, soil erosion is far from the only negative environmental effect of agriculture that can be reduced by smart intensification.
Related products
