Contribution of Harvest Residues to Nutrient Cycling in a Tropical Acacia mangium Willd. Plantation

Abstract

Harvest residues can play a crucial role in conserving nutrients for recycling in forests, but little is known about the rates of decomposition and nutrient release from these residues following logging in tropical acacia plantations. In this study, we examined the biomass and nutrient content of harvest residue components (bark, leaves, and branches) using the litterbag technique for a 1.5-year-period following harvest of a seven-year-old Acacia mangium plantation in Northern Vietnam. At harvest, the total dry biomass of harvest residues was 18 t ha−1 comprising bark (8.9 t ha−1), branches (6.6 t ha−1), and leaves (2.5 t ha−1). The retained bark on site conserved 51% N, 29% P, 32% K, 64% Ca, and 24% Mg content from harvest residues for recycling. Decomposition rate of the leaves was the most rapid (k = 1.47 year−1; t0.5 = 0.47 year), then branches (k = 0.54 year−1; t0.5 = 1.29 year), and bark (k = 0.22 year−1; t0.5 = 3.09 year). During decomposition, the loss of nutrients from harvest residues was K ≈ Ca > N > P> Mg. Decomposition of harvest residues and the associated rate of nutrient release can potentially supply a significant amount of nutrients required for stand development in the next rotation.

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

“…This finding fits well with the current plantation fertilization practice, which has demonstrated the benefits of P fertilization at time of planting [24,30]. Bich et al [37] emphasise the importance of P fertilization in Acacia plantations as it enhances microbial activity, decomposition rate, and microbial N fixation.…”

Growth Responses of Eucalyptus pellita F. Muell Plantations in South Sumatra to Macronutrient Fertilisers Following Several Rotations of Acacia mangium Willd.

“…Uptake of K by age 4 y was 207 kg ha −1 ; harvest residue can contain 166-190 kg K ha −1 in A. mangium [4], and 102-115 kg K ha −1 in A. auriculiformis [32]. Bich et al [33] reported that Ca and K released from the harvest residue of A. mangium occurred very rapidly, and at a faster rate than other nutrients. Application of K fertiliser has increased the productivity of eucalypt plantations in Brazil [34] but in that case the soils were highly weathered and low in primary minerals [35] and with low exchangeable K < 8 mg kg −1 [36] compared to >40 mg kg −1 in South Sumatra.…”

Limited effect of wood ash application on soil quality as indicated by a multisite assessment of soil organic matter attributes

“…The forest industry has been producing bioenergy through the combustion of residual materials (lignin/black liquor and woody residuals) to support their operations for nearly one century (Hannam et al, 2017) and wood wastes from harvesting, milling and manufacturing are increasingly being used as biomass fuel for bioenergy production (NRCan, 2020). Biomass removal on an industrial scale can contribute to the degradation of the site productivity over successive rotations (Van Bich et al, 2018) and result in increased soil acidity, which may negatively impact soil biodiversity (Jacobson et al, 2014; Reid & Watmough, 2014). Generally, the impact on nutrient removal and ecosystem function is proportional to the intensity of harvesting and the degree of biomass utilization (McFee & Kelly, 1995; Paré et al, 2002).…”