Grasslands cover nearly 40% of the Earth’s terrestrial surface and store large quantities of carbon (C) in their soils. However, grassland-use intensification, unsustainable management practices and climate change threaten this important C reservoir. Understanding how different grassland use intensities (GUI) influence soil C stocks is therefore essential to promote C accumulation and improve grassland sustainability. Although many studies have addressed this issue in recent decades, most have been conducted at local or regional scales, limiting our ability to detect general patterns because the response of soil C to GUI is strongly context dependent. Therefore, disentangling management effects from pedoclimatic factors is crucial to improving our understanding of how grassland management influences soil C.To address this knowledge gap, we investigated 46 grasslands across 15 sites located in Argentina, Colombia, Germany, Kenya, New Zealand, Spain and Switzerland, all sampled following a standardized protocol. Soil samples were collected at three depths (0–10, 10–20 and 20–30 cm) to quantify soil organic C and additional soil properties. Information on management practices was compiled for each grassland. Using livestock density (livestock unit grazing days ha−1 yr−1), the number of mowing events per year, and annual nitrogen fertilization (kg N ha-1 yr-1), we calculated the GUI index proposed by Blüthgen et al. (2012) which reflects the combined effects of these management practices.Our sites span a wide climatic gradient, with mean annual temperature ranging from 0.8 to 27.4°C, precipitation from 518 to 2357 mm, and aridity index from 0.42 to 3.49. Tropical and subtropical grasslands were generally characterized by low grazing intensity and little or no N fertilization, whereas temperate sites often combined grazing, mowing and, in some cases, high N fertilizer inputs. As a consequence, we obtained a wide range of GUI index values, from 0 in unmanaged conservation grasslands to values >10 in intensively managed systems in Switzerland and Germany. Preliminary analyses suggest that both the aridity index and the GUI index may play an important role in explaining variation of soil C concentrations across sites, underscoring the importance of GUI in shaping soil C storage. Ongoing analyses incorporating additional explanatory variables (i.e. clay, bulk density, biomass production or soil pH) will provide deeper insights into the drivers of soil C dynamics in grasslands worldwide.AcknowledgementsThis research was developed within the framework of the European Joint Program for SOIL, "Managing and Mapping Agricultural Soils for Enhancing Soil Functions and Services" (EJP SOIL), project CARBOGRASS, funded by the European Union Horizon 2020 research and innovation program (Grant Agreement No. 862695). UPM was funded by Project PCI2023-143386 funded by MCIN/AEI/ 10.13039/501100011033/EU. ILRI was funded by the CGIAR Science Programs Climate Action and Multifunctional Landscapes.ReferenceBlüthgen, N., Dormann, C. F., Prati, D., Klaus, V. H., Kleinebecker, T., Hölzel, N., ... & Weisser, W. W. (2012). A quantitative index of land-use intensity in grasslands: Integrating mowing, grazing and fertilization. Basic and Applied Ecology, 13(3), 207-220.

An increase in the frequency and intensity of agricultural and ecological droughts is expected. This study aimed to assess the response of annual forage dry matter production (AFP) to drought in 22 sites across Argentina’s silvopastoral systems (SPS) in native forests and forest plantations and compare it to grasslands and treeless pastures. The AFP was evaluated using a one-way ANOVA with a factorial design, considering the productive system (SPS and grassland/treeless pasture) and hydrological condition year (normal and dry) as factors. Mean AFP ranged from 195 kg DM ha−1 yr−1 to 18,520 kg DM ha−1 yr−1. The results showed that AFP varied according to aridity categories, drought intensity, and forage type (grassland and pastures). Under drought intensity ≤ 35

X° Congreso Internacional de Sistemas Silvopastoriles “Por una produccion sostenible”, Mariano Roque Alonso, Paraguay, del 24 al 26 de setiembre

The proper use of the environment in natural or transformed systems is a global issue and the most popular approach to its achievement is the development of diversified and environmentally friendly land-use systems that adopt adequate measures for its protection. In this sense, Silvopastoral Systems (SPS) that combine trees and animal production in the same area have an important role in diversifying and improving productivity in an environmentally friendly manner. In Misiones and Corrientes provinces (Argentina) the climate is defined as subtropical with frosts and a regular rainfall pattern; it is characterized by production diversification and yerba mate (Ilex paraguarensis) is an iconic crop. Forestry development is the most important in the country and SPSs currently take up around 100,000 ha in both provinces. They were particularly promoted in the past two decades following the results obtained in applied research and the transfer of technologies to the productive sector by the INTA (National Institute of Agricultural Technology), the Regional Consortia of Agricultural Experimentation, national and provincial agencies and other organizations of farmers. The information available about SPSs is presented, with reference to the production persistence of the forage component - grassland and pastures with an emphasis on the adaptation of C-4 forage species, improvement of their nutritive quality, effect of shade on soil fertility and cattle receptivity. The physical and mechanical properties of low density plantations (SPSs) were identified as significantly higher than in the intensive forestry system. Various methodologies are presented as applied to the economic and financial analysis of SPSs, like planning and management tools. The business limitations to the adoption of SPSs in both provinces include the capital investment required and, in the case of Misiones, the small size of the farms. The impact of SPSs is promising at a social level (higher income for the farms and genuine job generation), for the environment (sustainability of the resources), and for the economy of the territories (generation of products with a current or future differential value and efficient use of resources).

Agroforestry, which has multiple inputs and outputs, would benefit from scrutiny of economic efficiency because levels of adoption have not met expectations. Previous literature estimated the efficiency of agricultural systems using data envelopment analysis; however; the vast variability between farms makes comparing systems difficult. This study uses paired, within-farm comparisons of silvopasture, a combination of planted trees and pasture, to conventional cattle-ranching and plantation forestry, to evaluate the relative technical efficiency. Silvopasture proves to be more efficient than conventional cattle-ranching. Forestry demonstrated increasing returns to scale, cattle-raising demonstrated decreasing returns to scale for large-scale farmers, and silvopasture was intermediate.

Silvopasture systems combine trees, forage, and livestock in a variety of different species and management regimes, depending on the biophysical, economic, cultural, and market factors in a region. We describe and compare actual farm practices and current research trials of silvopastoral systems in eight regions within seven countries of the world: Misiones and Corrientes provinces, Argentina; La Pampa province, Argentina; northwestern Minas Gerais, Brazil; the Aysén region of Patagonia, Chile; the North Island of New Zealand; the Southeast United States; Paraguay; and Uruguay. Some countries use native trees and existing forests; some use plantations, particularly of exotic species. Natural forest silvopasture systems generally add livestock in extensive systems, to capture the benefits of shade, forage, and income diversification without much added inputs. Plantation forest systems are more purposive and intensive, with more focus on joint production and profits, for small owners, large ranches, and timber companies. Trends suggest that more active management of both natural and planted silvopastoral systems will be required to enhance joint production of timber and livestock, achieve income diversification and reduce financial risk, make more profit, improve environmental benefits, and realize more resilience to adapt to climate change.

Farmers' perceptions over time of an agroforestry technology can have an important impact on adoption and disadoption. Their perceptions, in turn, may be influenced by the type and scale of farm they own and the social networks they create. We examined the factors underlying producers' perceptions of silvopasture systems at the time of adoption and perceptions following several years of experienze, and the factors explaining discontinuance of systems in Argentina. We found that while most adopters indicated that other people influenced their decision about whether or not to adopt silvopasture, the type of person that influenced them (professionals vs. other farmers) did not affect adopters' perceptions of the relative benefits and challenges of the system. However, farm scale and farm type did explain farmers' perceptions to a good degree. Smaller-scale farmers were less likely to see costs and returns as benefits of the system, but more likely to see cash flow properties as important advantages. Farmers' perceptions after experiencing the system were good predictors of likely discontinuance, but influential people, farm scales, farm type, and perceptions at the time of adoption were not. (C) 2011 Elsevier Ltd. All tights reserved.

Differences between the theoretical benefits and the actual adoption of silvopasture systems among farmers have prompted researchers and extension agents to learn more about the adoption mechanisms for silvopasture systems. In the past decade, farmers in northeast Argentina's Misiones and northern Corrientes provinces have begun adopting silvopasture systems to a moderate extent. Interestingly, adoption has occurred among small-, medium- and large-scale farmers, either through individual decisions, or spurred by extension education and financial subsidy payments. This unique situation allows us to explore potential differences and similarities between the adoption and implementation of silvopasture between farmers of different scales. A survey of managers of the three farm scales in Misiones and northern Corrientes was used to determine advantages and disadvantages of the system, as perceived by managers. In addition, farmers were asked to describe economic costs incurred and benefits received from the silvopasture parcels. These data were used to compare the perceived merits, likelihood of continuance and production levels for silvopasture systems among the different farm-scale levels.

SUMMARY The native tropical forests provide 98% of the timber resources susceptible of gaining added values are rapidly declining. Wood provided by man made forests, with identical capabilities are starting to successfully replace them, and are still managing to maintain their value above the currencies depreciation. It's necessary to implement direct or intensive regimes, that include early thinnings and prunings, to obtain wood susceptible to attain added values. These regimes under occupy the sites productive capacity, enabling the introduction of agroforestry. Shading provided by the trees enable to increase both forage quality and animal weight gains and introduce britanic crosses. These aspects generate quality and acceptability in the world meat markets. It's then possible to obtain complementary degrees of production, obtaining superior quality wood and cattle goods on a same site. The combined system require higher monitoring than the isolated activities. The transformation pattern's required, specially for wood, are more easily implemented by medium size units that very large ones. They enable to generate employment, both direct in plantations and industry as indirect in the mechanics industry and multiple services associated. The conjunction of factors enable the establishment of the human resources involved with in sustainable production basket's. They require appropriate incentive policies on a regular basis.

SUMMARY In the north of Misiones Province a trial was established with the purpose to determine the relationship between Brachiaria brizantha forage biomass and different spacing of Pinus elliottii x Pinus caribaea var. Hondurensis (F2). Tree density varied from 70 to 2500 s.p.ha. During 1998 both, trees and pasture, was planted. The desing of the trial was a systematic, fan design with parallel rows. At three years of age, the pasture was grazed with high instant animal load, except inside a seasonal rotative closed area that covered all the densities weare total biomass was monitored. D.B.H., total height, green crown base, diameter over stubs was measured in each tree, also PAR in each treatment. It could be established relationship between forest canopies and forage biomass

SUMMARY It is necessary to understand farmers' perceptions and expectations of technologies in order to design appropriate extension programs and policy tools and to improve technologies. Previous research has shown that silvopasture systems could benefit farmers in various parts of the world, but adoption has only been moderate, implying that farmers' perceptions of the system may be somewhat different than researchers'. A survey of silvopasture adopters of varying scales was taken in northeastern Argentina to investigate their perceptions of the advantages and disadvantages provided by the system. The farmers perceived the most important advantages to be improved microclimate and diversified cash flow, while the most important disadvantages were competition between trees and forage species, and the complex management that the system requires. These perceptions differed somewhat from farmers' initial expectations of the system, before adoption. In general, adopters indicated that they would probably continue or expand silvopasture plots, with or without further policy intervention.