Browsing by Subject "Agroforstsystem"

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Participatory evaluation of sustainability of farming systems in the Philippines
(2010) Vilei, Sonja; Dabbert, Stephan
Forest cover in the Philippines has been greatly reduced in the past and slightly recovered since, estimated at around 24% of land surface currently. Small-scale farmers have to survive on small landholdings (2 ha on average and mostly under 5 ha), face insecure land tenure, and the high population density leaves little scope for gaining new agricultural land. Their farming systems continue to form an important part of their livelihoods, but often their strategies are unsustainable in the long run. While the need for evaluating common farming systems and compare them with new alternatives exists, it is important to involve local stakeholders in the search for suitable sustainability indicators. In this study, the search was based on the Sustainable Rural Livelihoods Framework and therefore organised under its five types of capital assets: natural, financial, physical, human and social capital. Farmers from five study sites along the Western side of the island of Leyte were gathered in eight focus group discussions to discuss the issues of success and sustainability of their farming systems and identify and rank possible criteria for an evaluation of sustainability. Nine other stakeholders from the same sites were interviewed individually. In a second research phase, all 49 identified criteria were given to 30 farmers and 18 other stakeholders for ranking. Three groups of farmers from the municipality of Baybay were used for comparison: one group of rice and coconut farmers; a second group with (additional) exotic timber trees (usually Gmelina and Acacia mangium); a third group with (additional) indigenous timber trees (?Rainforestation Farming?). The identified indicators were tested regarding their usefulness for comparing the three groups of farmers. Rainforestation Farming, as promising alternative farming system, was analysed further regarding financial aspects and its adoptability with regard to small-scale farmers. The Sustainable Rural Livelihoods Framework was useful for identifying suitable evaluation criteria. The importance of the five capital assets groups was perceived similarly by farmers and other stakeholders, but ranking results for single criteria (i.e. soil quality, membership in organisation) differed. The same holds true when comparing results for the four study regions, where the individual ranking was carried out: significant differences existed for single, mostly financial, criteria (i.e. record-keeping, investment costs) but not for importance of the five capital asset groups. The ranking results differed quite substantially, though, between focus groups and individual farmers, indicating on the one hand the influence of group leaders. But, on the other hand, farmers had the complete list of criteria for the individual ranking, including several criteria which they had not thought of previously, but which they still regard as important. Fifteen criteria were selected as indicators for comparing the three farmers groups. Rainforestation farmers were the group scoring significantly higher on most indicators (i.e education level adults and children, land available per capita, (perceived) soil quality, number of soil conservation measures used, membership in organisation) than farmers without timber trees. Farmers having planted exotic timber trees scored closer to Rainforestation farmers. But to be able to judge if the specific farming system leads to a more sustainable livelihood, time series data would have been necessary. The data of this study allowed concluding that tree farmers planting (indigenous or exotic) timber trees are endowed with higher resources ? more land, higher income, higher education levels. Most likely they had these resources before starting their farming systems. In addition, these farmers were also more actively engaged in organisations and had more contact to extension agents, therefore enhancing their social (and human) capital. The higher score regarding (perceived) soil quality and (non-) use of pesticides these farmers groups reached are likely to be an outcome of the farming system practiced. Analysing the financial feasibility and adoptability of Rainforestation Farming, it shows that the system has the potential to be profitable, but coming with a high risk: investment costs are very high and it takes up to 13 years to regain them. Consequently, the first adopters either had unused land areas or substantial off-farm income, and the subsequent adoption rate is low. Sustainability has to be understood as a dynamic and not a static concept and the concept of sustainable land management must consequently evolve as well. This study tried to add further findings regarding the use of suitable methods for this cause, but as already mentioned above, time series data would be necessary to assess the progress of farming systems towards ?sustainability?.
Soil moisture dynamics in integrated crop - livestock - forestry systems in the Cerrado Biome in Central - West Brazil
(2021) Glatzle, Sarah; Asch, Folkard
The Cerrado biome in Brazil covers about 200 million ha and is a global biodiversity hotspot. Over the last decades, the Cerrado biome underwent and is still undergoing an excessive expansion in agriculture. Deforestation and replacement of the natural Savannah vegetation by cropland and pasture contributes to serious environmental problems, including soil degradation and altered water cycles. The integrated crop-livestock-forestry (ICLF) system is currently promoted as a measure for sustainable intensification. It improves the use of cultivated areas, recovers previously degraded land, and could be a strategy for adapting agriculture to climate change. Despite being considered a key indicator of how integrated systems affect ecological processes, soil moisture (SM) dynamics in literature have not been consistently analyzed, and continuous observation of seasonal SM dynamics are mostly unaddressed. Since SM of complex ecosystems is influenced by numerous factors, several additional parameters need to be considered to create a comprehensive understanding of the interlinked processes, such as radiation, rainfall, and biomass. The objective of this cumulative PhD thesis was to investigate SM dynamics and aboveground grass biomass under different land use systems in the Cerrado biome of Central West Brazil. In the first study, photosynthetically active radiation (PAR) received at grass canopy level, SM, AGBM between the tree rows, and seasons in a mature ICLF system were investigated. Across the seasons, a distinct gradient was observed with SM being lower close to the tree rows than in the space between them. During winter, SM in the topsoil decreased to critical values, and dropped to the permanent wilting point next to the tree rows. During spring and summer, incident PAR was lower close to the trees than at the center point, while during autumn and winter, when PAR is generally lower, it was more evenly distributed between the tree rows. Aboveground grass biomass (AGBM) showed a distinct distribution within the ICLF system with maximum values in the center and about 50% of the biomass close to the tree rows. The results suggest that, restrictions in AGBM accumulation shifted among seasons between water limitations in winter and light limitations during summer. In the second study, the seasonal and spatial variability of SM of Cerrado soils under four different land use systems was investigated under consideration of soil physical characteristics and grass biomass. In rainy and dry season, SM in the upper 100 cm of the soil was highest in the integrated crop-livestock (ICL) system, followed by the continuous pasture (COP), and lowest in the land use systems including trees, ICLF and Cerrado. Whereas in COP and in ICL, water was mainly taken up from the upper 30 cm, in ICLF, the strongest soil moisture depletion was observed between a soil depth of 40 and 100 cm. Although in the Cerrado SM in the topsoil was lower than in the other land use types, water was conserved below 60 cm depth. Both integrated systems improved soil properties, such as bulk density and soil organic carbon compared to COP, and increased biomass productivity was observed, demonstrating the benefits of the integrated systems over the traditional grazing system. The results suggest that ICLF systems show increased evapotranspiration compared to conventional pasture and other integrated systems without trees. In the third study, the effects of the presence of eucalyptus trees on the seasonal pasture and animal performance in ICLF systems 8 years after establishment were investigated. Forage morphology, production, and nutritive value plus performance of Nellore heifers in two ICLF systems with varying in trees density, were evaluated and compared with a grass-only pasture. In both ICLF systems, the forage nutritive values were improved compared with a grass-only pasture. Nevertheless, grass biomass and accumulation rate were higher in the grass-only pasture. By the 8th year, the ICLF systems were unable to support both forage and animal production equivalent to a grass-only pasture, due to the high impact of the Eucalyptus trees on radiation received at the grass canopy and on soil moisture. Improved soil characteristics and forage nutritive values compared to grass-only pastures, and the potential restoration of natural ecosystem functions regarding water recycling into the atmosphere, demonstrated the benefits of ICLF systems and highlight their potential to contribute to sustainable agricultural intensification. However, high water consumption by trees poses a risk to grass productivity during the dry season and thus, the system may consequently not be used for grazing all year round. Therefore, research on management options mitigating the impact of drought on grass productivity is needed. As the impact of the trees on the system is highly dependent on their age, these studies should consider the entire life cycle of the system.