Assessment of Nutrient Release From Harvest Residues and the Roles of Buffer Aeas and Seeded Vegetation in Nutrient Retention in Harvested Blanket Peat Forests

Zaki-ul-Zaman Asam, Mika Nieminen, Annu Kaila, Afshan Sana, Sakari Sarkkola, Connie O’Driscoll, Mark O’Connor, Michael Rodgers , Liwen Xiao

Proceedings of the 14th International Peat Congress


blanket-peat, buffer-area, flumes, simulated-rainfall

Asam et al 2012: Assessment of Nutrient Release From Harvest Residues and the Roles of Buffer Aeas and Seeded Vegetation i


Theme VII. Ecology and management on forested peatlands


The mature blanket peatland forest catchments are efficient P and N conservation ecosystems
and hydrological losses of P and N are low. However, forest harvesting disrupts the nutrient
cycling, reduces the nutrient conservation capacity and results in increased nutrient release to
water bodies. To protect the water quality deterioration, whole-tree harvesting and use of
buffer areas are proposed as a means to decrease nutrient release. However, the efficiency of
buffer areas in blanket peat catchments may be low due to frequent occurrence of high
hydraulic loadings. This study uses laboratory flumes, simulated rainfall and overland flows
to study the nutrient release dynamics from brash windrows, and to predict the efficiency of
buffer areas in retaining nutrients under high hydraulic loadings. The results suggested that
decay of brash windrows is a major source of P release soon after clear-felling but not a
source for N. Retention of dissolved reactive P (DRP) by buffer area flumes decreased
significantly with increasing hydraulic loading. During high hydraulic loading the grassed
flumes retained 50% more DRP than the non-grassed flumes, however, the overall retention
was less than 28%, suggesting that buffer areas in blanket peatland forests may not be
efficient in P retention. Therefore other mitigation methods like stimulating the growth of
native grasses on clear-felled area should be studied as a mean of increasing onsite retention
and reducing nutrient export from blanket peatlands.