Supporting Participatory Agroforestry for Erosion Control in Bengawan Solo Watershed, Indonesia
 
Large-scale deforestation and land clearing for intensive farming on the highly erosive and steep-sloped uplands of the Bengawan Solo Watershed in Indonesia have caused severe land degradation and soil erosion. How to rehabilitate this fragile ecosystem and prevent soil erosion became an economy-level concern for Indonesia.
To solve this problem sustainably, an integrated approach using agroforestry and grey infrastructure using civil engineering methods at the micro-catchment level might be the solution. Starting in 2017, APFNet funded two phases (2017-2019, 2020-2022) of the project “Development of participatory management of a micro-catchment in the Bengawan Solo Upper Watershed”, which have now both been successfully completed. The project selected the Naruan Micro Catchment (NMC) in the upstream area of Bengawan Solo River as a pilot site to showcase participatory measures to tackle soil erosion. In order to make sure that the needs of the local community and existing knowledge were sufficiently considered, this project used a participatory approach that involved local farmers in decision-making during planning, implementation and subsequent monitoring.
 
Controlling Erosion while Benefitting People
The upstream watershed, where the project was located, plays a crucial role in erosion control as slopes there are often steep and unsuitable land use causes erosion, affecting not only the local population but all downstream areas. Unfortunately, due to the complex interaction between topography (steep slopes, insufficient land cover) and hydrology (rainfall and run-off), soil erosion and land degradation in the NMC are difficult to fully halt and reverse on a large scale in the short term. Complicating this, most of the people living in this rural area depend on farming for their livelihoods, inevitably causing soil erosion. As such, it was the task of the APFNet project to find measures that can control erosion while also allowing people to earn a living sustainably. For this, a practical and operational plan was developed and demonstration sites were established.

 

Fig.1: Agroforestry demonstration site established by APFNet project in Naruan Micro Catchment, Central Java, Indonesia

 
To find a compromise between preventing erosion by turning agriculture back into forests and traditional agriculture rotating seasonal crops that have been practised so far, the project team developed a participatory management plan that mostly uses agroforestry. In response to participating farmers’ needs, timber trees like albizia and limpaga and multi-purpose trees, such as avocado, coffee or lemon, were integrated with the cropping designs (Fig.1), with a greater focus on non-timber trees to minimize soil disturbance caused by farming. The APFNet project, in total about 90ha, involving more than 200 land owners, has been planted and managed according to these principles. Besides the support of participating farmers, the project succeeded in bringing together various stakeholders, such as the regional and local government, watershed research institutions, NGOs and the local, state-owned water supply company, who are committed to continuing soil and water conservation practices post-project.
In addition to those vegetative measures, erosion was addressed through the construction of grey infrastructure that used civil engineering measures. These included check dams and gully plugs for erosion control, built from various materials, like cemented stones, gabion (Fig.2), or bamboo. By installing a series of these in gullies, the project was able to stabilize them and prevent them from further deterioration. 

 

Fig.2: Before and after construction of a gully plug for controlling water erosion in fields along steep slopes

 
All measures were implemented with the local community, namely the farmers from the three villages in the NMC. In order to enable them to act effectively both throughout and post-project, the participating farmers were trained on several relevant topics, such as sustainable land management, construction of gully plugs, as well as additional skills that would enable them to diversify their income generation, such as apiculture, coffee and avocado cultivation and waste treatment. This way they do not need to rely on cash crop production alone. The training was held in each village and was well received by the local communities . All training was a combination of theory and practice and was conducted by experienced trainers. As an incentive to apply the new skills, after the beekeeping training, ten colonies of Trigona laeviceps (the stingless bee) were handed over to each village. The coffee workshops included training on cultivation, post-harvest processing and how to make different types of coffee drinks. After the avocado grafting training, the participants can reproduce avocado seedlings themselves and through learning grafting techniques plant productivity is expected to increase.
The APFNet-project has just been completed and therefore it is impossible to already see the long-term impacts of project activities. However, the analysis of data generated in Phase I already shows the advantages of using agroforestry (compared to tree monocultures or traditional agriculture) as it offers the best cost-benefit ratio to farmers. In this project phase, a policy brief on village-based participatory micro-watershed management addresses potential improvements in watershed management planning regulations, e.g. concerning the size definitions of managed areas and integration into village development programs. Moving forward, the NMC and its watershed management will function as a model for participatory watershed management in Indonesia. The methods for community participation and participatory intercropping designs are further shared through upcoming scientific papers and publications. The approach of agroforestry in combination with physical barriers, such as gully dams, will provide long-term erosion control and reduce the sediment load in rivers in downstream areas.
Overall, the project has already made a positive impact in the area and beyond and is expected to continue to do so.
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