Silvopastoral systems for enhanced productivity, environmental sustainability and rural development

Grassland type Cultivated

Name of practice Silvopastoral systems for enhanced productivity, environmental sustainability and rural development

Name of main actor Ranchers of Minas Gerais state, Brazil

Type of actor(s) Farmers, Pastoralists

Location Brazil

Agro-ecological region Tropical

Sustainability dimension involved Environmental, Economic, Social

Sustainability sub-themes Atmosphere, Water, Land, Biodiversity, Animal Welfare, Investment, Decent Livelihood

Year of implementation 1990

Description of best practice The Brazilian savannah (Cerrado) is the largest in the Americas, extending over 200 million ha. The Cerrado biome is a global biodiversity hotspot; it is the world’s richest savannah in botanical diversity and provides a habitat for many endemic plant, bird, fish, reptile, amphibian and insect species. Moreover, the Cerrado is a significant terrestrial sink of soil organic carbon. Due to ongoing conversion to agriculture since the 1960s, this unique ecosystem is now considered threatened. In particular, deforestation to cultivate pastures for livestock production has been driven by an increased export demand for beef and later for dairy products. Such land use changes have negative impacts on indigenous peoples, lead to biodiversity and habitat loss, and are a significant source of GHG emissions. The environmental impacts caused by deforestation are further compounded by the degradation of cultivated pastures. Degradation is a common problem in the Cerrado, as tropical soils are prone to loss of soil fertility if not properly managed. In particular, Soil Organic Matter (SOM) conservation is essential for maintaining ecosystem services including soil structure, nutrient cycling and water balance. The loss of productivity of degraded pastures increases deforestation pressure to clear new land for grazing. Silvopastoral systems (SPS) are a promising management option to address the problems of land degradation and deforestation and enhance environmental, economic and social sustainability. SPS were established in the 1990s, initially on a private farm in Minas Gerais state utilizing natural regeneration of native trees to build the agroforestry and livestock system. Since then, SPS have steadily increased in the Cerrado, mostly utilizing eucalyptus trees, shade-tolerant Brachiaria brizantha forage and beef-cattle grazing in a mixed system. Incorporating trees and pasture helps to restore soil fertility by providing a steady supply of organic matter in the litter. The shade under trees creates a microclimate that increases soil moisture availability and N-mineralization, improving forage quality and nutrition. Trees also provide thermal comfort for animals through shade and shelter. As a result, SPS improve animal production while allowing the possibility of income diversification, combining timber, and meat/milk products. Consequently, SPS can enhance livelihoods and promote rural development. In addition to on-site environmental and economic benefits, SPS contribute to global public goods of biodiversity conservation and carbon sequestration and environmental services. Compared to monocultures, SPS have a higher complexity, with species richness comparable to early secondary forests. SPS help mitigate climate change through above and below ground carbon sequestration. By improving productivity and restoring degraded pastures, sustainable practices such as SPS help to ease deforestation pressure, preventing further biodiversity loss and carbon emissions.

Outcomes and impacts A number of scientific studies have evaluated the impacts of SPS: In the state of Minas Gerais, southeast Brazil, an experiment showed superior pasture characteristics and animal performance in SPS compared to monocultures (Paciullo et al. 2011). SPS pastures had higher crude protein values while shade did not hinder pasture growth. Dairy heifers had a higher annual weight gain in the SPS, both per animal and per ha. These results support the findings of Sousa et al. (2010), that the tree component of the SPS increased forage mass dry matter by 47% and crude protein content by 37%. In contrast, tree litterfall from a SPS in Lagoa Santa, Minas Gerais, contained considerable inputs of N and K, but there was no significant increase in these soil nutrient pools (Reis et al. 2010). It is possible that greater differences would have been measured if the area had previously suffered further degradation. This result serves to illustrate the biological complexity of SPS. Site specific interactions among the components (tree, forage, and animal), must be understood and effectively managed to optimize productivity. Successful SPS are often specific to local social, economic and ecological conditions, where creative ‘farmer experimenters’ have a fundamental role to play, learning from and adapting to local conditions. The Projectos Demonstrativos (PDA) database lists a number of successful initiatives supporting conservation and sustainable use of natural resources in the Legal Amazon region. Agroforestry systems (including SPS) make up a significant element of many of these projects: (available in Portuguese: http://www.mma.gov.br/estruturas/pda/_arquivos/Estrutura%20-%20Institucional%20-%20Tabela%20de%20Projetos%20PDA%20Fase%20I.html). However, despite the positive outcomes that SPS can achieve, the uptake of SPS in the Cerrado has been less than expected. Significant barriers to widespread adoption remain. Constraints may include a lack of secure tenure rights, access to rural credit, training opportunities and specific technical assistance, or the opportunity to participate in collectives linking producers to buyers. Without incentives to encourage SPS adoption, it is likely to be cheaper to deforest new agricultural frontiers than invest in developing SPS. Porro et al. (2012) argue that comprehensive policies to support the uptake of SPS should emphasize inter-linkages between reduction of poverty and hunger, deforestation and the carbon sequestration. However, the most important incentive for SPS should linked to the payment for environment services where the incomes generated by benefits for the agricultural landscape and biodiversity/water conservation will motivate farmers and also compensate the high cost during implementation or even due to high biological complexity of the management (personal communication: Mauricio, R.M). Several other benefits from SPS, were also described by experiences in Colombia (CIPAV - http://www.cipav.org.co/) and Mexico (Fundaccion Produce - http://www.producemich.org.mx/), including high stocking rates, low external inputs, landscape connectivity and others (Murgueitio et al. 2011). References: Nair, P.K.R., Tonucci, R.G., Garcia, R. and Nair, V.D. (2011) “Silvopasture and Carbon Sequestration with Special Reference to the Brazilian Savanna (Cerrado)” in B. Kumar and P.K.R. Nair (eds.), Carbon Sequestration Potential of Agroforestry Systems: Opportunities and Challenges, Advances in Agroforestry 8, Springer: 145-162. Paciullo, D., de Castro, C., Gomide, C., Maurício, R., Pires, M., Müller, M., Xavier, D. (2011) “Performance of dairy heifers in a silvopastoral system”, Livestock Science, 141: 166–172. Porro, R., Miller, R.P., Tito, M.R., Donovan, J.A., Vivan, J.L., Trancoso, R., Van Kanten, R.F., Grijalva, J.E., Ramirez, B.L. and Gonçalves, A.L. (2012) “Agroforestry in the Amazon Region: A Pathway for Balancing Conservation and Development” in P.K.R. Nair and D. Garrity (eds.), Agroforestry – The Future of Global Land Use, Advances in Agroforestry 9, Springer: 391-428. Reis, G., Lana, A., Maurício, R., Machado, R., Borges, I. and Neto, T. (2010) “Influence of trees on soil nutrient pools in a silvopastoral system in the Brazilian Savannah”, Plant Soil, 329: 185-193. Sousa, L., Maurício, R., Moreira, G., Gonçalves, L., Borges, I. and Pereira, L. (2010) “Nutritional evaluation of ‘Braquiarão’ grass in association with ‘Aroeira’ trees in a silvopastoral system”, Agroforestry Systems, 79: 189-199. Margueitioa, E., Calle, Z., Uribea, F., Calle, A. and Baldomero, S. (2011) “Native trees and shrubs for the productive rehabilitation of tropical cattle ranching lands”, Forest Ecology and Management, 261: 1654-1663.

Contacts Rogerio M. Mauricio Bio-Engineering Department (DEPEB) Federal University of São Joao Email: [email protected]