Increased agricultural use of tropical peatlands has negative environmental effects. Drainage leads to landscape-wide degradation and fire risks. Livelihood strategies in peatland ecosystems have traditionally focused on transitions from riverbanks to peatland forests. Riparian ‘Kaleka’ agroforests with more than 100 years of history persist in the peatlands of Central Kalimantan (Indonesia), where large-scale open-field agricultural projects have dramatically failed. Our field study in a Dayak Ngaju village on the Kahayan river in the Pulang Pisau district involved characterizing land uses, surveying vegetation, measuring soil characteristics, and monitoring groundwater during a period of 16 months. We focused on how local practices and farmer knowledge compare with standard soil fertility (physical, chemical, biological) measurements to make meaningful assessments of risks and opportunities for sustainable land use within site-specific constraints. The Kaleka agroforests around a former settlement and sacred historical meaning are species-rich agroforests dominated by local fruit trees and rubber close to the riverbank. They function well with high wet-season groundwater tables (up to −15 cm) compatible with peatland restoration targets. Existing soil quality indices rate the soils, with low soil pH and high Alexch, as having low suitability for most annual crops, but active tree regeneration in Kaleka shows sustainability.

If 150 years of continued use counts as a sustainability indicator, the river-bank agroforests in the peat landscapes of Central Kalimantan suggest solutions for current challenges. The 2015 fire season in Indonesian peatlands triggered a fire ban and peatland restoration response, prioritizing canal blocking and rewetting. However, sustainable livelihood options remain elusive. We report local ecological knowledge of soils and vegetation applied in land use choices in swiddens and agroforests in five Dayak Ngaju villages in Jabiren Raya and Kahayan Hilir subdistrict (Pulang Pisau, C. Kalimantan, Indonesia) on the banks of the Kahayan river and discuss impacts of fire-ban policies. Plots accessible from the river with no or shallow peat were traditionally preferred for swiddening, with various indicator plants and soil characteristics underpinning the choices. Without swiddening farmers depend on off-farm jobs and agroforests for income. More policy attention for non-peat riparian-zone agroforestry as part of peat landscape livelihood systems is warranted.

Peatlands are shaped by slow litter decomposition, but threshold decomposition rates that allow peat formation remain unclear. Can agroforestry in the tropics be compatible with paludiculture that allows peat formation? We explored the determinants of litter decomposition in wet agroforests adjacent to tropical peatlands in Central Kalimantan (Indonesia) by litterbag studies (up to 16 weeks) with standing litter sources to estimate rate constants, characterize litter quality (especially lignin (L), polyphenolics (Pp) and nitrogen (N)), and monitor temperature and groundwater levels. In litter transfer experiments we tested for home-field advantage (HFA) effects between land cover types. Mean residence times around 85 weeks at 27 °C were associated with a high (L + Pp)/N ratio. However, in the crossover treatments, mean residence times varied from 30 to 180 weeks and strong HFA effects (up to 80% faster decomposition at “home”) were found when litter from other sources was tested in old fruit-based agroforests. HFA indicates a local decomposer community well-adapted to its normal litter diet. Litter residence times of around two years are below the apparent peat formation threshold. Maintaining wet agroforest conditions adjacent to peat domes supports peatland rewetting and restoration but does not contribute to on-site peat formation processes.