Acuña, H., Alonso, M., Ayala, W., Balocchi, O., Dorner, J., Flores, P., Hernández-Garay, A., Keim, J.P., Kemp, P.H, Laca, E., López, I.
Grasslands constitute one of the largest biomes of the planet, with an extension of 46 million km2, which represents 26% of the land and 80% of the agricultural land of the world. They are present in every continent, excluding Antarctica, and distributed in a wide range of edaphic and climatic conditions, from those too wet to be deserts to those too dry to sustain forests.
The evolution of humans has been tightly linked to the emergence of grasslands. Since the appearance of the first hominids, grasslands were the main scenario for their evolution, promoting the development of the traits that make us humans. At the beginning they were a place for hunting and gathering, as well as for the domestication of wild animals and a primitive agriculture. Nowadays, grasslands are the basis for highly developed global industries, such as the meat, milk and wool industries. Moreover, 68% of the grasslands are in developing countries, where they play a central role in the life of millions of farmers.
Grasslands are areas dominated by herbaceous vegetation that can be consumed directly by herbivores or harvested for fresh or conserved forage. The floristic composition of grasslands varies, including grasses, legumes, other forbs and shrub and tree species. Thus, there is a wide variety of grasslands, from natural grasslands to short rotation seeded pastures. Despite the differences between them, they all share the same role as the basis of grazing systems, especially with ruminants. In this context, grasslands serve as the link between soils and animals, generating foods of high nutritional value for humans. The high demand for animal products, which is expected to reach a 25% increase by 2030, will require greater efficiency and sustainability of grazing systems to satisfy the needs of the present generation without sacrificing the potential to provide for future generations.
Although the main role of grasslands at the present is to support domestic animals, grasslands also sustain wild ecosystems and offer multiple goods and services, such as biodiversity conservation, recovery of degraded soils, water harvest and CO2 sequestration. All aspects of grasslands have been the object of extensive scientific research, originating different fields of work. In this special issue of the Agro Sur journal titled “Contribution of grasslands to the development of sustainable production systems”, we present advances in some of these fields.
Thus, this issue includes articles about grasslands with a wide geographical distribution, from California in the USA, to New Zealand and the Chilean Patagonia. Articles introduce results of a wide range of topics, from ordination and classification of rangelands to response of grasslands productivity to different conditions of soil fertility, irrigation, management and stress. The collection includes articles on defoliation, selectivity, intake and seed recruitment, and on the effect of grasslands on soil physical properties. We trust that these articles will contribute to the advancement of knowledge on the structure, function and management of grasslands worldwide.