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Lydie-stella Koutika - One of the best experts on this subject based on the ideXlab platform.
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afforesting savannas with acacia mangium and eucalyptus improves p availability in Arenosols of the congolese coastal plains
Geoderma Regional, 2019Co-Authors: Lydie-stella KoutikaAbstract:Abstract Phosphorus (P) is an essential constituent for all living organisms, scarce with finite reserves. P is deficient in Sub Saharan Africa threatening primary production. That in part is due to the occlusion of P in Fe and Al oxides in the weathered soils. This problem is aggravated by the high cost of P fertilizers, lack of both appropriate technologies for its application and government support to facilitate and strengthen its use in small-scale farming. Evaluation of soil P availability in the mixed-species plantations established on natural savannas in the Congolese coastal plains highlights that high C accretion involves low P availability in the mixed-species (50% acacia and 50% eucalyptus) stands relative to others. P availability in 0–0.05 m in the mixed-species stands (6.94 ± 0.45 mg kg−1) was lower than in acacia (8.07 ± 0.63 mg kg−1) and eucalyptus (8.46 ± 0.79 mg kg−1). C stock in the 0.25 m was higher in the mixed-species (17.8 ± 0.7 t.ha−1) relative to acacia (16.7 t.ha−1 ± 0.4) and eucalyptus (15.9 t.ha−1 ± 0.4). However, afforesting the inherently nutrient-poor and sandy soils beneath savannas evidenced an improvement in soil P availability to plant, along with soil N status and C sequestration in both soil and biomass, with a potential impact on mitigating climate change.
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acacia and eucalypt change p n and c concentrations in pom of Arenosols in the congolese coastal plains
Geoderma Regional, 2017Co-Authors: Lydie-stella Koutika, Louis MareschalAbstract:Abstract As an active part of soil organic matter (SOM), particulate organic matter (POM; 4000–50 μm) quickly reveals changes occurring in SOM status after land-use change. To evaluate the impact of planting eucalypts and acacias in the tropical savannas of Congolese coastal plains on SOM quality, we determined P, N and C concentrations in POM in the 0–10 cm layer in afforested stands (pure or in combination) and savannas. Soil available P in the coarse fraction of POM (cPOM; 4000–250 μm) in afforested stands (> 60 mg kg− 1) was higher than in savannas (11 mg kg− 1), probably due to both high P content and high decomposition rates of organic residues that have accumulated over a 30-year period. However, only in the afforested stands containing acacias was N concentration (> 1.50%) in cPOM higher than in savannas ( 1.25%) was significantly higher than in savannas (
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nitrogen dynamics in a nutrient poor soil under mixed species plantations of eucalypts and acacias
Soil Biology & Biochemistry, 2017Co-Authors: Lydie-stella Koutika, Louis Mareschal, Sogni Viviane Tchichelle, Daniel EpronAbstract:Abstract Introducing nitrogen-fixing species (NFS) in eucalypt plantations is a useful practice to compensate nitrogen loss at harvest, reduce fertilizer inputs, improve soil fertility and sustain forest productivity in low input systems. Nitrogen (N) and carbon (C) were evaluated in the active part of soil organic matter (SOM) i.e., the particulate organic matter (POM), which was obtained after soil (0–0.05 m) physical fractionation at the end of a first 7-year rotation (R1Y7) and at year 2 of a second rotation (R2Y2) in pure acacia (100A), pure eucalypt (100E) and mixed-species (50A50E) stands in an experimental plantation established on an Arenosol in the Congolese coastal plains. N concentration (in g kg−1 of soil) was higher in coarse POM (cPOM, 4000–250 μm) in 100A and 50A50E compared to 100E at 2YR2, while no difference was found in fine POM (fPOM, 250–50 μm) and in the organo-mineral fraction (OMF,
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differences in nitrogen cycling and soil mineralisation between a eucalypt plantation and a mixed eucalypt and acacia mangium plantation on a sandy tropical soil
Southern Forests, 2017Co-Authors: Sogni Viviane Tchichelle, Lydie-stella Koutika, Daniel Epron, Fidele Mialoundama, Jeanmichel Harmand, Jeanpierre Bouillet, Louis MareschalAbstract:Sustainable wood production requires appropriate management of commercial forest plantations. Establishment of industrial eucalypt plantations on poor sandy soils leads to a high loss of nutrients including nitrogen (N) after wood harvesting. An ecological intensification of eucalypt plantations was tested with the replacement of half of the Eucalyptus urophylla × E. grandis by Acacia mangium in the eucalypt monoculture to sustain soil fertility through enhancement of the N biological cycle. A randomised block design was set up on ferralitic arenosol in the Congolese coastal plains to assess differences in soil N mineralisation, N fluxes in litterfall, and N stocks in forest floor litter and soil between pure acacia (100A), pure eucalypt (100E) and mixed-species treatments (50A50E). Soil N mineralisation was enhanced under acacia, reaching on average 0.17 and 0.15 mg kg−1 soil d−1 in 100A and 50A50E, respectively, compared with 0.09 mg kg−1 soil d−1 in 100E. Higher amounts of N returning to the soil throu...
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soil p availability under eucalypt and acacia on ferralic Arenosols republic of the congo
Geoderma Regional, 2016Co-Authors: Lydie-stella Koutika, Louis Mareschal, Daniel EpronAbstract:Abstract Introducing nitrogen fixing species (NFS) in forest plantations reduces soil N-limitation, but also involves changes in phosphorus (P) availability in the Ferralitic Arenosols of the Congolese coastal plains or Bateke Plateaux in Central Africa. We evaluated soil-available P and total P in above-ground litters, leaves, bark and wood in pure (100A, 100E) and mixed-species (50A50E) stands of acacia (a NFS) and eucalypt plantations in the Congolese coastal plains at year 2 of the second rotation (Y2R2) compared to the end of the first 7-year rotation (EndR1). Soil available P was measured as resin P, bicarbonate-extractable inorganic (P i -HCO 3 ) and organic (P o -HCO 3 ). Soil resin-P values (15–19 mg P kg − 1 ) in 100E were 80% higher relative to 100A (8–17 mg P kg − 1 ) at Y2R2 against no difference for both 100E and 100A (8–12 mg P kg − 1 ) at EndR1. Total P concentration was higher in acacia wood (0.61 g P kg − 1 of dry mass (DM)) than in eucalypt wood (0.57 g P kg − 1 of DM) in 50A50E at Y2R2, while higher stock of P and higher ratio of N:P ratios were found in the foliage of acacia than of eucalypt trees. Our data suggests that the risk of shifting from N-limitation to P-limitation system is minor. However, in the long term, P-limitation may eventually occur in pure acacia plantations, due to mining of soil available P by acacia's higher P uptake relative to eucalypt and additional requirement for symbiotic fixation of atmospheric N 2 .
Jerzy Jonczak - One of the best experts on this subject based on the ideXlab platform.
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late vistulian and holocene development of litho morpho pedogenic processes in the southern baltic coastal zone a case study from debina northern poland
Geoderma, 2019Co-Authors: Jerzy Jonczak, Monika Niska, Waclaw Florek, Boguslawa Kruczkowska, Joanna Gadziszewska, łukasz UzarowiczAbstract:Abstract The study aimed to reconstruct major phases of the litho-morpho-pedogenic processes in the southern Baltic coastal zone near Debina in northern Poland. Five profiles of fossil soils in the coastal cliff were described, sampled and analysed using standard procedures. The studied outcrop covers a sequence of deposits, including the basal till of the Świecie Stadial (MIS 4) of the Vistula Glaciation, the ablation till of the Pomeranian Phase (MIS 2) of the Vistula Glaciation, the thin cover of glacilimnic sand, the lacustrine sediments filling the palaeolake basin, and aeolian deposits of varied age. A sequence of paleosols developed successively within these deposits during the Late Vistulian and Holocene (MIS 1). The initialization of soil-forming processes occurred under the influence of periglacial environment and pioneer tundra vegetation. Endostagnic Podzols (Abruptic, Epiarenic, Endoloamic, Endodensic) developed within the plateau, and they have some features typical for periglacial environments (e.g. the presence of a cryoilluvial horizon, the poor humification of soil organic matter, the low abundance in N and P, and the vertical displacement of P). The basin of a small lake has been filled successively with sediments and Dystric Endocalcaric Katostagnic Fluvisols (Arenic, Humic, Endolimnic) developed from these sediments during the Late Vistulian and Early Holocene. The previously mentioned soils were buried by sandy cover in the Early Subatlantic due to intensification of aeolian processes. Ortsteinic Podzols (Pantoarenic) developed within a newly formed sandy cover. A fossil fireplace preserved in the top of these soils constitutes evidence of human activity dating back almost 2000 years. Ortsteinic Podzol (Pantoarenic) are dissected by a dry valley that developed as a result of some fluvial episode, perhaps induced by human activity. It was subsequently filled with aeolian sands, and Dystric Arenosols (Aeolic, Ochric) developed within them. Ortsteinic Podzol (Pantoarenic) and Dystric Arenosols (Aeolic, Ochric) were buried approximately five centuries ago. Our findings for the studied cliff section correlate well with results of other authors concerning the postglacial dynamics of morphogenetic processes. The studies provide significantly enriched geomorphological knowledge related to the formation of relief in the study area, with pedological aspects.
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impact of scots pine admixture in european beech stand on dissolved organic carbon and nitrogen leaching from organic and humic horizons of dystric Arenosols in northern poland
Journal of forest science, 2018Co-Authors: Jerzy Jonczak, Agnieszka ParzychAbstract:The effect of Scots pine admixture in European beech stand on the leaching of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), nitrate nitrogen (NO 3 -N) and ammonium nitrogen (NH 4 -N) from organic and humic horizons of Dystric Arenosols was studied in northern Poland in 2008-2009. Three zero-tension lysimeters under organic and humic horizons were installed in pure beech and mixed pine-beech stands. Water samples were collected after each rainfall, measured volumetrically, filtered and analysed. In each sample pH and concentrations of DOC, DON, NH 4 -N and NO 3 -N were analysed. Stronger acidification of leachates was observed in mixed stand compared to pure beech. About twice higher concentration of DOC and its fluxes per unit area were determined in mixed stand. The fluxes of DOC from unit mass of soil were less varied. In general, lower concentrations of DON, NH 4 -N and NO 3 -N as well as fluxes of the components (calculated in mg·kg -1 DM·year -1 and mg·m -2 ·year -1 ) were observed in mixed stand.
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influence of pine and spruce admixture in european beech stand on some properties of organic and humic horizons of dystric Arenosols and the intensity of biological turnover
Polish Journal of Soil Science, 2016Co-Authors: Jerzy Jonczak, Katarzyna MackiewiczAbstract:The aim of the study has been to assess the influence of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies) admixture in European beech (Fagus sylvatica) stand on some properties of organic and humic horizons of Dystric Arenosols and the intensity of biological turnover. The studies were conducted in northern Poland in Łysomice Forest Subdistrict (Forest District Leśny Dwor, Regional Directorate of State Forest Szczecinek). Significant differences in some properties of examined soil horizons were noticed between the stands. About 3-times higher stocks of organic matter in ectohumus were found in beech-pine and about 2-times in beech-spruce in relation to pure beech stand. Higher stocks of soil organic matter recorded in beech-pine and beech-spruce stands may result from the influx of coniferous litter and reduction of the intensity of biological turnover. The stocks of organic matter in A horizons were slightly higher in beech stand. Lower values of pH in O and A horizons were found in mixed stand in relation to pure beech. The concentration of nitrogen was comparable in both stands. It can be assumed that spatial variability of the stocks of nitrogen was strongly related to spatial diversity of soil organic matter stocks.
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vertical distribution of cu ni and zn in brunic Arenosols and gleyic podzols of the supra flood terrace of the slupia river as affected by litho pedogenic factors
Forest Research Papers, 2015Co-Authors: Jerzy JonczakAbstract:The aim of the study was to assess the influence of lithological and pedogenic factors in the shaping of Cu, Ni and Zn distribution patterns in the profiles of Brunic Arenosols and Gleyic Podzols of the lower supra-flood terrace of the Slupia River, which is located outside the range of significant anthropogenic sources of pollution with these metals. The contents of the investigated metals were analysed in aqua regia extracts of samples collected from three profiles of Brunic Arenosols, formed from river sands, and three profiles of Gleyic Podzols, formed from river sands trans- formed by eolian processes. In general, river sands contained higher amounts of Ni and Zn (2.6 - 6.9 mg·kg -1 Ni; 10.3 - 16.2 mg·kg -1 Zn) com- pared to eolian sands (1.2 - 2.4 mg·kg -1 Ni; 3.3 - 17.3 mg·kg -1 ), while the content of copper tended to be higher in eolian sands (1.3 - 1.9 mg·kg -1 ) than river sands (0.1 - 1.5 mg·kg -1 ). The observed differences between the two types of sand are due to the loss of fine granulometric fractions and various minerals during eolian processes. Higher con- centrations of the investigated metals in soil solum as compared to parent material are due to their uptake from deeper parts of the soil by roots and subsequent return to the soil surface as a component of litterfall. Therefore, the highest concentrations of Cu, Ni and Zn were observed in ectohumus. In the mineral component of the soil, the highest con- centrations were observed in organic matter-rich A and B horizons, which indicate close interactions between heavy metals, humic substances and iron oxides. The vertical distribution of the investigated metals in the profiles of Gleyic Podzols indicates their leaching during podzolization. The observed contents of Cu, Ni and Zn, both in Brunic Arenosols and Gleyic Podzols, were lower than the geochemical background, which confirms that anthropogenic contamination of the studied area with these metals is marginal.
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uwarunkowane litopedogenicznie rozmieszczenie cu ni i zn w profilach leœnych gleb rdzawych i glejobielicowych terasy nadzalewowej s upi vertical distribution of cu ni and zn in brunic Arenosols and gleyic podzols of the supra flood terrace of the s u
2014Co-Authors: Jerzy JonczakAbstract:The aim of the study was to assess the influence of lithological and pedogenic factors in the shaping of Cu, Ni and Zn distribution patterns in the profiles of Brunic Arenosols and Gleyic Podzols of the lower supra-flood terrace of the S³upia River, which is located outside the range of significant anthropogenic sources of pollution with these metals. The contents of the investigated metals were analyzed in aqua regia extracts of samples collected from three profiles of Brunic Arenosols, composed of river sands, and three profiles of Gleyic Podzols, composed of river sands transformed by eolian processes. In general, river sands contained higher amounts of Ni and Zn (2.6-6.9 mg·kg -1 Ni; 10.3-16.2 mg·kg -1 Zn) compared to eolian sands (1.2-2.4 mg·kg -1 Ni; 3.3-17.3 mg·kg -1 ), while the content of copper tended to be higher in eolian sands (1.3-1.9 mg·kg -1 ) than river sands (0.1-1.5 mg·kg -1 ). The observed differences between the two types of sand are due to the loss of fine granulometric fractions and various minerals during eolian processes. Higher concentrations of the investigated metals in soil solum as compared to parent material are due to their uptake from deeper parts of the soil by roots and subsequent return to the soil surface by litter fall. Therefore, the highest concentrations of Cu, Ni and Zn were observed in ectohumus. In the mineral component of the soil, the highest concentrations were observed in organic matter-rich A and B horizons, which indicate close interactions between heavy metals, humic substances and iron oxides. The vertical distribution of the investigated metals in the profiles of Gleyic Podzols indicates their leaching during podzolization. The observed contents of Cu, Ni and Zn, both in Brunic Arenosols and Gleyic Podzols, were lower than the geochemical background, which confirms that anthropogenic contamination of the studied area with these metals is marginal.
Louis Mareschal - One of the best experts on this subject based on the ideXlab platform.
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acacia and eucalypt change p n and c concentrations in pom of Arenosols in the congolese coastal plains
Geoderma Regional, 2017Co-Authors: Lydie-stella Koutika, Louis MareschalAbstract:Abstract As an active part of soil organic matter (SOM), particulate organic matter (POM; 4000–50 μm) quickly reveals changes occurring in SOM status after land-use change. To evaluate the impact of planting eucalypts and acacias in the tropical savannas of Congolese coastal plains on SOM quality, we determined P, N and C concentrations in POM in the 0–10 cm layer in afforested stands (pure or in combination) and savannas. Soil available P in the coarse fraction of POM (cPOM; 4000–250 μm) in afforested stands (> 60 mg kg− 1) was higher than in savannas (11 mg kg− 1), probably due to both high P content and high decomposition rates of organic residues that have accumulated over a 30-year period. However, only in the afforested stands containing acacias was N concentration (> 1.50%) in cPOM higher than in savannas ( 1.25%) was significantly higher than in savannas (
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nitrogen dynamics in a nutrient poor soil under mixed species plantations of eucalypts and acacias
Soil Biology & Biochemistry, 2017Co-Authors: Lydie-stella Koutika, Louis Mareschal, Sogni Viviane Tchichelle, Daniel EpronAbstract:Abstract Introducing nitrogen-fixing species (NFS) in eucalypt plantations is a useful practice to compensate nitrogen loss at harvest, reduce fertilizer inputs, improve soil fertility and sustain forest productivity in low input systems. Nitrogen (N) and carbon (C) were evaluated in the active part of soil organic matter (SOM) i.e., the particulate organic matter (POM), which was obtained after soil (0–0.05 m) physical fractionation at the end of a first 7-year rotation (R1Y7) and at year 2 of a second rotation (R2Y2) in pure acacia (100A), pure eucalypt (100E) and mixed-species (50A50E) stands in an experimental plantation established on an Arenosol in the Congolese coastal plains. N concentration (in g kg−1 of soil) was higher in coarse POM (cPOM, 4000–250 μm) in 100A and 50A50E compared to 100E at 2YR2, while no difference was found in fine POM (fPOM, 250–50 μm) and in the organo-mineral fraction (OMF,
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differences in nitrogen cycling and soil mineralisation between a eucalypt plantation and a mixed eucalypt and acacia mangium plantation on a sandy tropical soil
Southern Forests, 2017Co-Authors: Sogni Viviane Tchichelle, Lydie-stella Koutika, Daniel Epron, Fidele Mialoundama, Jeanmichel Harmand, Jeanpierre Bouillet, Louis MareschalAbstract:Sustainable wood production requires appropriate management of commercial forest plantations. Establishment of industrial eucalypt plantations on poor sandy soils leads to a high loss of nutrients including nitrogen (N) after wood harvesting. An ecological intensification of eucalypt plantations was tested with the replacement of half of the Eucalyptus urophylla × E. grandis by Acacia mangium in the eucalypt monoculture to sustain soil fertility through enhancement of the N biological cycle. A randomised block design was set up on ferralitic arenosol in the Congolese coastal plains to assess differences in soil N mineralisation, N fluxes in litterfall, and N stocks in forest floor litter and soil between pure acacia (100A), pure eucalypt (100E) and mixed-species treatments (50A50E). Soil N mineralisation was enhanced under acacia, reaching on average 0.17 and 0.15 mg kg−1 soil d−1 in 100A and 50A50E, respectively, compared with 0.09 mg kg−1 soil d−1 in 100E. Higher amounts of N returning to the soil throu...
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soil p availability under eucalypt and acacia on ferralic Arenosols republic of the congo
Geoderma Regional, 2016Co-Authors: Lydie-stella Koutika, Louis Mareschal, Daniel EpronAbstract:Abstract Introducing nitrogen fixing species (NFS) in forest plantations reduces soil N-limitation, but also involves changes in phosphorus (P) availability in the Ferralitic Arenosols of the Congolese coastal plains or Bateke Plateaux in Central Africa. We evaluated soil-available P and total P in above-ground litters, leaves, bark and wood in pure (100A, 100E) and mixed-species (50A50E) stands of acacia (a NFS) and eucalypt plantations in the Congolese coastal plains at year 2 of the second rotation (Y2R2) compared to the end of the first 7-year rotation (EndR1). Soil available P was measured as resin P, bicarbonate-extractable inorganic (P i -HCO 3 ) and organic (P o -HCO 3 ). Soil resin-P values (15–19 mg P kg − 1 ) in 100E were 80% higher relative to 100A (8–17 mg P kg − 1 ) at Y2R2 against no difference for both 100E and 100A (8–12 mg P kg − 1 ) at EndR1. Total P concentration was higher in acacia wood (0.61 g P kg − 1 of dry mass (DM)) than in eucalypt wood (0.57 g P kg − 1 of DM) in 50A50E at Y2R2, while higher stock of P and higher ratio of N:P ratios were found in the foliage of acacia than of eucalypt trees. Our data suggests that the risk of shifting from N-limitation to P-limitation system is minor. However, in the long term, P-limitation may eventually occur in pure acacia plantations, due to mining of soil available P by acacia's higher P uptake relative to eucalypt and additional requirement for symbiotic fixation of atmospheric N 2 .
Adia Grozav - One of the best experts on this subject based on the ideXlab platform.
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aeolian sediment psamosols and or Arenosols
Research Journal of Agricultural Science, 2014Co-Authors: R Bertici, G Rogobete, Adia GrozavAbstract:Aeolian processes, involving erosion, transportation and deposition of sediment by the wind, occur in a variety of environments, including beaches, semi-arid and arid regions, agricultural fields. Wind, blowing over dry sand, initiates movement in much the same way as water. The result is that sands moved by air tend to very well sorted and also well rounded. There are three modes of sediment transport by wind: creep or reptation, saltation, and suspension. Erosion by wind involves abrasion and deflation. Major dust source areas Tchad, the Aral Sea area, SE Iran, and the loess plateau of China. Aeolian deposits include sand seas and dune fields, deposit of silt and fine - grained material. Dunes are composed of moderately to well - sorted sands (63-1000µm) with a mean grain size in the range 160-300 µm. Most dune sands are composed of quartz, but may include significant quantities of feldspar. Major areas of sand seas lie in the tectonically desert regions of the Sahara, Arabian Peninsula, Australia, S. Africa and central Asia. Many Aeolian deposits are formed during the Quaternary Era, thus they have, been now soils. In SRTS 2012, Psammosol is the soil type developed from Aeolian sand, including soils that have a mollic, an umbric or an ochric A horizon, followed by parent materials of Aeolian sandy deposits ≥50 cm thick and have ≤12% clay. We have analysed and compared soil profiles from Banat region (Lovrin), Satu Mare (NW of Romania) - Nir river, and Oltenia region (Dăbuleni). Psammosols correlated in WRB-SR-1998 with Arenosols. Arenosols are a reference soils group with a texture that is coarser than sandy loam to a depth of least 100 cm from the surface and having less than 35 per cent of rock fragments. These soils occur on deep Aeolian, marine, lacustrine and alluvial sands. The total estimated extent is 900 million hectares. Because the modern Geology classified rocks using Latin terms (arena - sand, rudectus - stony, lutum - loamy, and argilla - clay), we consider that aspect important for our Latin language, and in that view promote to substitute Psammosol with Arenosol. Evidently, there are many reasons for that, exponded in this article.
Daniel Epron - One of the best experts on this subject based on the ideXlab platform.
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nitrogen dynamics in a nutrient poor soil under mixed species plantations of eucalypts and acacias
Soil Biology & Biochemistry, 2017Co-Authors: Lydie-stella Koutika, Louis Mareschal, Sogni Viviane Tchichelle, Daniel EpronAbstract:Abstract Introducing nitrogen-fixing species (NFS) in eucalypt plantations is a useful practice to compensate nitrogen loss at harvest, reduce fertilizer inputs, improve soil fertility and sustain forest productivity in low input systems. Nitrogen (N) and carbon (C) were evaluated in the active part of soil organic matter (SOM) i.e., the particulate organic matter (POM), which was obtained after soil (0–0.05 m) physical fractionation at the end of a first 7-year rotation (R1Y7) and at year 2 of a second rotation (R2Y2) in pure acacia (100A), pure eucalypt (100E) and mixed-species (50A50E) stands in an experimental plantation established on an Arenosol in the Congolese coastal plains. N concentration (in g kg−1 of soil) was higher in coarse POM (cPOM, 4000–250 μm) in 100A and 50A50E compared to 100E at 2YR2, while no difference was found in fine POM (fPOM, 250–50 μm) and in the organo-mineral fraction (OMF,
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differences in nitrogen cycling and soil mineralisation between a eucalypt plantation and a mixed eucalypt and acacia mangium plantation on a sandy tropical soil
Southern Forests, 2017Co-Authors: Sogni Viviane Tchichelle, Lydie-stella Koutika, Daniel Epron, Fidele Mialoundama, Jeanmichel Harmand, Jeanpierre Bouillet, Louis MareschalAbstract:Sustainable wood production requires appropriate management of commercial forest plantations. Establishment of industrial eucalypt plantations on poor sandy soils leads to a high loss of nutrients including nitrogen (N) after wood harvesting. An ecological intensification of eucalypt plantations was tested with the replacement of half of the Eucalyptus urophylla × E. grandis by Acacia mangium in the eucalypt monoculture to sustain soil fertility through enhancement of the N biological cycle. A randomised block design was set up on ferralitic arenosol in the Congolese coastal plains to assess differences in soil N mineralisation, N fluxes in litterfall, and N stocks in forest floor litter and soil between pure acacia (100A), pure eucalypt (100E) and mixed-species treatments (50A50E). Soil N mineralisation was enhanced under acacia, reaching on average 0.17 and 0.15 mg kg−1 soil d−1 in 100A and 50A50E, respectively, compared with 0.09 mg kg−1 soil d−1 in 100E. Higher amounts of N returning to the soil throu...
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soil p availability under eucalypt and acacia on ferralic Arenosols republic of the congo
Geoderma Regional, 2016Co-Authors: Lydie-stella Koutika, Louis Mareschal, Daniel EpronAbstract:Abstract Introducing nitrogen fixing species (NFS) in forest plantations reduces soil N-limitation, but also involves changes in phosphorus (P) availability in the Ferralitic Arenosols of the Congolese coastal plains or Bateke Plateaux in Central Africa. We evaluated soil-available P and total P in above-ground litters, leaves, bark and wood in pure (100A, 100E) and mixed-species (50A50E) stands of acacia (a NFS) and eucalypt plantations in the Congolese coastal plains at year 2 of the second rotation (Y2R2) compared to the end of the first 7-year rotation (EndR1). Soil available P was measured as resin P, bicarbonate-extractable inorganic (P i -HCO 3 ) and organic (P o -HCO 3 ). Soil resin-P values (15–19 mg P kg − 1 ) in 100E were 80% higher relative to 100A (8–17 mg P kg − 1 ) at Y2R2 against no difference for both 100E and 100A (8–12 mg P kg − 1 ) at EndR1. Total P concentration was higher in acacia wood (0.61 g P kg − 1 of dry mass (DM)) than in eucalypt wood (0.57 g P kg − 1 of DM) in 50A50E at Y2R2, while higher stock of P and higher ratio of N:P ratios were found in the foliage of acacia than of eucalypt trees. Our data suggests that the risk of shifting from N-limitation to P-limitation system is minor. However, in the long term, P-limitation may eventually occur in pure acacia plantations, due to mining of soil available P by acacia's higher P uptake relative to eucalypt and additional requirement for symbiotic fixation of atmospheric N 2 .