Nutrient Balance as a Tool for Maintaining Yield and Mitigating Environmental Impacts of Acacia Plantation in Drained Tropical Peatland—Description of Plantation Simulator

Abstract

Responsible management of Acacia plantations requires an improved understanding of trade-offs between maintaining stand production whilst reducing environmental impacts. Intensive drainage and the resulting low water tables (WT) increase carbon emissions, peat subsidence, fire risk and nutrient export to water courses, whilst increasing nutrient availability for plant uptake from peat mineralization. In the plantations, hydrology, stand growth, carbon and nutrient balance, and peat subsidence are connected forming a complex dynamic system, which can be thoroughly understood by dynamic process models. We developed the Plantation Simulator to describe the effect of drainage, silviculture, fertilization, and weed control on the above-mentioned processes and to find production schemes that are environmentally and economically viable. The model successfully predicted measured peat subsidence, which was used as a proxy for stand total mass balance. Computed nutrient balances indicated that the main growth-limiting factor was phosphorus (P) supply, and the P balance was affected by site index, mortality rate and WT. In a scenario assessment, where WT was raised from −0.80 m to −0.40 m the subsidence rate decreased from 4.4 to 3.3 cm yr−1, and carbon loss from 17 to 9 Mg ha−1 yr−1. P balance shifted from marginally positive to negative suggesting that additional P fertilization is needed to maintain stand productivity as a trade-off for reducing C emissions.

Agroforestry as an approach to rehabilitating degraded tropical peatland in Indonesia

“…Peatland conversion exacerbates the hydrological consequences through the induction of additional drainage-induced modifications, specifically peat subsidence, which augments the vulnerability to flooding. Physical and biological processes contribute to subsidence, including peat compaction subsequent to water table reduction and peat oxidation above water table, which promotes microbial decomposition and carbon dioxide release into the atmosphere Laurén et al, 2021). The configuration of the peat dome undergoes temporal variation due to drainage subsidence, an effect that concurrently diminishes the carbon storage capacity (Cobb et al, 2020).…”

“…For the purposes of peat conservation and fire prevention, the government may direct the transformation of degraded land into productive land; however, this cannot be overly intensively managed. The annual subsidence of peat by agroforestry and agricultural practises ranges from 0.41 to 3.21 cm (Evans et al, 2021), consequently elevating the vulnerability to flooding. On the other hand, peatlands have the potential to support animalrelated industries, including horticulture, fish farming, and goat husbandry (Tan et al, 2020).…”

NutSpaFHy—A Distributed Nutrient Balance Model to Predict Nutrient Export from Managed Boreal Headwater Catchments

“…Responsible forest management requires balancing between the economic gains and adverse environmental effects of the production [1]. In Nordic and Baltic countries, forestry has a significant role in national and regional economies but also risks adverse environmental effects.…”