Temperature Simulation: An Integrated Approach (original) (raw)
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Revista Ra e Ga, 2023
The objective of the study was to understand the influence of Eucalyptus spp. cultivation on the quality of the environment in which it is inserted. For this, three sampling areas of eucalyptus plantations and a control area composed of heterogeneous vegetation. Measurements of leaf litter mass loss, water retention capacity (WRC) tests, and measurements of the content of macronutrients and organic fractions (lignin, cellulose and polyphenols) were carried out in the litter. The litter samples from the control area showed a decomposition coefficient (k) (0.78; 0.82; 0.87) significantly higher than the samples from Eucalyptus spp. (0.51; 0.52; 0.55). For WRC, samples from the control area showed values between 161% and 339%, with an average value of 260%. These were significantly higher than those in the eucalyptus areas, which varied between 72% and 156%, with an average value equal to 112%. As for the content of macronutrients, for the concentration of N, Mg and S in the litter, the samples collected in the control area showed average values significantly higher than the samples from the eucalyptus areas. Regarding the contents of lignin and polyphenols, the samples collected in the eucalyptus areas showed significantly higher values than those presented by the control area. The results obtained showed a strong statistical correlation between the contents of N, Mg, lignin and polyphenols in the sampled leaf material, decomposition rates and water retention capacity. The decomposition of Eucalyptus spp. presented slow decomposition, strongly linked to its chemical composition, which hinders the action of decomposing agents.
Forest Ecology and Management, 2002
Leaf litter from stands of Eucalyptus globulus Labill., of varying chemical composition was used to study decomposition rates and the release of nutrients (N, P, S, K, Ca, Mg). Leaf litter from control plots, which received no additional fertiliser or water (C), from fertilised plots (F), from irrigated plots (I) and from irrigated and fertilised plots (IL and ILN) was used. IL was collected during June-July and ILN during September. The C, F and I contained lower N and P than the IL and ILN, and had also a lower lignin content. Litterbags were used to study decomposition during a period of 643 days. The remaining ash free weight after 643 days of incubation ranged from 52.8% in C leaf litter to 47.9% in ILN leaf litter. The decomposition rates of leaf litter were 0.37 per year for C and 0.42 per year for ILN. Decomposition rates and weight losses were not significantly different among leaf litters, irrespective of different N and P concentrations, C/N ratios and lignin/N ratios. The concentration of N, S, and Ca in all substrates studied were higher at the end of the incubation period than at the beginning whereas the concentrations of K and Mg were lower. P concentration was lower at the end than at the beginning of the experiment, except for C leaf litter. The increase in N concentration was inversely correlated to its concentration in the original leaf litter. During the early decomposition stages (133 days), release of N, P and Ca was positively correlated to their initial concentration. Except for S and Ca, the amount of N, P, Mg and K remaining at the end of the experiment was similar to that determined after the early decomposition stages. The improvement of leaf litter quality through fertiliser application did not increase decomposition rate, but the release of N and P was enhanced.
Soil Biology & Biochemistry, 1998
SummaryÐChemical changes in decomposing Scots pine needles exposed for 22 months in litter bags in central France forest were determined using near infrared re¯ectance spectroscopy (NIRS). Concentrations of N, P, cellulose, lignin, lignin-C and lignin-N content were related to accumulated mass loss. Litters from the litter bags exposed for 2, 4, 8, 12 and 16 months in situ were incubated for 1 additional year in the laboratory under controlled conditions, and CO 2 release was measured (carbon mineralisation potential). Asymptotic and exponential functions were ®tted to these data and de®ned respirometric fractions with low, intermediate and high decomposition rates. In addition, litter (L), fermentation (F) and humus (H) layers from the site were incubated in the laboratory under the same conditions. The correspondence analysis, using the parameters of the asymptotic functions as variables, showed that the carbon mineralisation potential of the naturally-decomposing litter collected at the site was similar to the mineralisation potential of the material in the litter exposed in bags for about 1 yr in the ®eld. Nevertheless the decomposition rates observed under laboratory conditions should be interpreted with caution since they were considerably lower than the decomposition rates of the same litter exposed in situ. #
Decomposition of eucalyptus leaves in litter mixtures
Soil Biology and Biochemistry, 1996
Leaf litter from Eucalyptus globulus was decomposed alone and in mixture with either oak (Querncs petraeu), ash (Fraxinus excelsior) or birch (Bet&r pendulu) leaf litter under laboratory conditions. Decomposition was monitored as CO* release and leaching of inorganic N over 13 weeks. At the end of the experiment, litters were separated into their species components and analyzed for mineral composition (K, Ca, Mg, P and N) and mass loss. Differences between expected and measured rates of decomposition were evaluated, based on a comparison between the results from the pure litters and the mixtures. Mixing eucalyptus litter with oak litter resulted in enhanced total CO* release from the litter mixture when compared with the pure components. Similar, but less marked, positive interactions were observed in mixtures with eucalyptus + birch and eucalyptus + ash. Decomposition of eucalyptus litter in the presence of the other litters also influenced N mineralisation, resulting in greater net N retention in the mixtures with eucalyptus + oak and eucalyptus + birch, but a decrease in mixture with ash. The results support the conclusion that the decomposition of litters in mixtures cannot be readily predicted from the hehaviour of the component litters decomposing in isolation. We suggest that mixtures of eucalyptus with other litters could be one mechanism by which the high productivity rates of eucalyptus plantations may be maintained, and that manipulation of litter mixtures could assist in synchronising nutrient release and plant uptake.
Forest Ecology and Management, 2009
The potential export of nutrients from Eucalyptus plantations harvested for pulp production may be high. However, depending on the harvest method, the nutrients from the residue can be recycled. The aims of this study were (i) to quantify the content and distribution of nutrients in different residue components at harvest for a Eucalyptus dunnii Maiden plantation; and (ii) to quantify the decomposition rates of the harvest residues, and the return of nutrients to the soil in the temperate climate conditions of Uruguay. Six trees of a 9-year-old E. dunnii plantation with average diameter at breast-height (DBH) were harvested, and the biomass produced and the N, P, K, Ca and Mg contents in commercial and noncommercial logs, leaves, branches, bark and litter were estimated. Decomposition of the remains of leaves, branches, non-commercial logs, bark and litter was studied in the field for 2 years. Although commercial logs accounted for 61% of the biomass produced, only 27% of the N, 35% of the P, 18% of the K, 16% of the Ca and 41% of the Mg present in the forest were exported with the product. When logs are exported without de-barking in the site, the nutrient export would increase to 41%, 55%, 46%, 68% and 66% of the total extraction of N, P, K, Ca and Mg, respectively. Residue decomposition showed that the leaves lost the highest proportion of biomass (half life 0.86 years), and bark was most resistant to decomposition in the field (half life 5.36 years). As regards the nutrients, K was lost most rapidly and Ca showed the slowest loss, while N, P and Mg losses were generally more gradual, and proportional to the decomposition rate. ß
Plant and Soil, 2014
Aims Tropical plantations are likely to supply a growing share of the increasing world demand for forest products. We aimed to gain insight into the role of the nitrogen (N) contained in harvest residues (HR) for tree growth and soil N stocks. Methods We used 15N-labeled harvest residues to (1) study the dynamic of N release throughout decomposition, (2) determine the vertical transport pathways of N from the forest floor to the upper soil layers, and (3) quantifying the contributions of HR to soil N stocks and the supply of N to young Eucalyptus trees. Results Almost all of the 15N initially contained in the HR was recovered 27 months after deposition, with 21 % remaining in HR, 38 % being transferred to the underlying O layer, 21 % being transferred to the 0-15 cm soil layer, and approximately 15 % accumulating in the tree biomass. Our results supported the presence of two pathways of N transfers from the O layer to the mineral soil: (1) the leaching of dissolved 15N from fresh litter during the first year after planting which actively contributed to Eucalyptus N nutrition and (2) the transport of particulate organic matter in percolating water which contributed to maintain N stocks in the first 15 cm of the soil. Approximately 40 % of the N content in 2-yearold Eucalyptus trees was derived from the labeled HR. Conclusions The sustainability of fast-growing Eucalyptus trees established on N-poor sandy tropical Plant Soil (2014) 376:245-260
Soil Biology and Biochemistry, 2003
This study compared field and laboratory decomposition rates of coarse woody debris (CWD) (.10 cm diameter) from three tree species: Pinus radiata, Eucalyptus regnans, and Eucalyptus maculata. For this purpose, the density loss of logs on the ground sampled from chronosequences of sites following harvesting was determined using the water replacement technique. P. radiata logs were sampled 1, 2.5, 6, and 9 years following harvesting, and logs of E. regnans and E. maculata were collected from sites that were harvested 1, 3.5, 6.5, and 12 and 1.5, 6.5, and 11.5 years ago, respectively. In addition, the C/N ratio of wood was determined and current respiration rates of logs from these different age classes were measured through laboratory incubation. The times for loss of 95% of material (t 0.95 ) determined from density loss for these species were 24 years for P. radiata, 43 years for E. regnans, and 62 years for E. maculata. The decomposition rates of CWD derived from laboratory respiration were 6.1, 5.9 and 11.9 times higher than the decay rates from density loss in P. radiata, E. regnans, and E. maculata, respectively. This points to severe constraints of decomposition through adverse conditions in the field. The changes in respiration rates and C/N ratio with age of decaying logs indicated that the single component, negative exponential decay model could be applied satisfactorily only to P. radiata. In the case of the eucalypt species, substrate quality (expressed through respiration rates) declined in the oldest samples. This may be explained by the loss of rapidly decomposing sapwood and the retention of more decay-resistant heartwood. In these cases, a two-component model will be more suitable to describe the density loss of decaying wood. q
Forest Ecology and Management, 1999
Sustainable management of forest resources, including nutrient retention and protection of the soil structure, is required to ensure long-term soil fertility and productivity of later rotations. Potential depletion of soil nutrients is particularly likely in production systems based on fast-growing trees, such as eucalypts. We have studied production of second rotation Eucalyptus globulus stands at two sites in northern Spain and two in central Portugal, after replanting or coppicing, under four treatments, in which plant residues from the ®rst crop were utilised. The residues were either removed from the sites (Treatment R), spread over the soil surface (Treatments S, uniform spreading, and W, in which the woody debris was con®ned to rows between the trees) or incorporated into the soil by harrowing to 15-cm depth (Treatment I). We measured tree height and girth at intervals over three growing seasons, and root biomass at the Portuguese sites. Decomposition of three residue components: leaves-plus-bark, twigs and branches, was measured in litter bags placed in the position corresponding to the placement of the organic residues.
Bosque (Valdivia)
Descomposición y mineralización de la hojarasca foliar en plantaciones de Eucalyptus grandis en tres tipos diferentes de suelos en Entre Ríos, Argentina SUMMARY The decay of organic matter returned to the soil via litter fall is an important source of nutrients for vegetation uptake. The rate of decomposition of organic matter, release, and immobilization of nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron and aluminum of fresh leaf litter of Eucalyptus grandis were measured using litter bags in three trial plots located on an Oxic Quartzipsamment (red sandy), a Fluventic Haplumbrept (dark sandy), and an Argiudolic Pelludert soil (black clay soils). The annual rate of decay of dry matter (k) was faster in clay soil (0.44) than in both sandy soils (0.30). Temporal patterns of changes in nutrient concentration in leaf litter were similar at both sandy soil sites compared to the clay soil. Nitrogen and phosphorus increased over time at all sites, but their immobilization was greater at the clay soil site. Calcium, magnesium and manganese fluctuated with a different pattern in each soil type. Iron and aluminum showed a similar pattern of increasing concentration at each site. A higher rate of dry mass loss, together with an increase in nitrogen and phosphorus immobilization, was observed at the more fertile clay soil site.
Source-driven remobilizations of nutrients within stem wood in Eucalyptus grandis plantations
Trees, 2013
Nutrient remobilizations in tree ligneous components have been little studied in tropical forests. A complete randomized block design was installed in Brazilian eucalypt plantations to quantify the remobilizations of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) within stem wood. Three treatments were studied: control with neither K nor Na addition (C), 3 kmol ha-1 K applied (?K), and 3 kmol ha-1 Na applied (?Na). Biomass and nutrient contents were measured in the stem wood of eight trees destructively sampled at 1, 2, 3 and 4 years after planting in each treatment and annual rings were localized on discs of wood sampled every 3 m in half of the trees. Chemical analyses and wood density measurements were performed individually for each ring per level and per tree sampled. Nutrient remobilizations in annual rings were calculated through mass balance between two successive ages. Our results show that nutrient remobilizations within stem wood were mainly source-driven. Potassium and Na additions largely increased their concentration in the outer rings as well as the amounts remobilized in the first 2 years after the wood formation. The amount of Na remobilized in annual rings was 15 % higher in ?Na than in ?K the fourth year after planting despite a 34 % higher production of stem wood in ?K leading to a much higher nutrient sink. A partial substitution of K by Na in the remobilizations within stem wood might contribute to enhancing Eucalyptus grandis growth in K-depleted soils.