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  • 1
    Language: English
    Description: A series of 18 short cores has been obtained from the Lehnmühle reservoir (operation since 1932) in eastern Erzgebirge (Germany) in order to investigate the effects of the severe flood event in August 2002 on sedimentation by combining microfacies and high resolution μ-XRF scanning techniques. A distinct graded detrital layer, unique for the whole record, appears in almost the entire reservoir basin, ranging in thickness from 33 mm at proximal sites close to the river inflow to 5 mm at distal sites. The total sediment influx during this event was estimated to approximately 2,400 tons. Around two-thirds of the sediment was deposited in the southern-central part of the basin (approx. 32 % of the basin area) due to basin morphometry and proximity to the inflow. An enhanced flux of fine silt and clays to areas near the dam was observed and is likely driven by a steady current towards the dam. Occurrence of detrital material in a lateral bay reveals that sediment derived not only from the main inflow but also from surface runoff through non-permanently water bearing stream channels around the reservoir. In addition to the exceptional 2002 flood layer, 22 microscopically thin detrital layers were detected in the...
    Keywords: Geology, Hydrology, Meteorology ; Lake Sediments, Flood Events, Detrital Layers, Microfacies Analysis, Eastern Erzgebirge, Water Supply Reservoir
    ISSN: 04247116
    E-ISSN: 21999090
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  • 2
    Language: English
    In: Forests, 01 November 2016, Vol.7(12), p.302
    Description: A growing interest in using forest biomass for bioenergy generation may stimulate intensive harvesting scenarios in Germany. We calculated and compared nutrient exports of conventional stem only (SO), whole tree without needles (WT excl. needles), and whole tree (WT) harvesting in two medium aged Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) stands differing in productivity, and related them to soil nutrient pools and fluxes at the study sites. We established allometric biomass functions for each aboveground tree compartment and analyzed their nutrient contents. We analyzed soil nutrient stocks, estimated weathering rates, and obtained deposition and seepage data from nearby Level II stations. WT (excl. needles) and WT treatments cause nutrient losses 1.5 to 3.6 times higher than SO, while the biomass gain is only 1.18 to 1.25 in case of WT (excl. needles) and 1.28 to 1.30 in case of WT in the pine and spruce stand, respectively. Within the investigated 25-year period, WT harvesting would cause exports of N, K+, Ca2+, and Mg2+ of 6.6, 8.8, 5.4, and 0.8 kg·ha−1 in the pine stand and 13.9, 7.0, 10.6, and 1.8 kg·ha−1 in the spruce stand annually. The relative impact of WT and WT (excl. needles) on the nutrient balance is similar in the pine and spruce stands, despite differences in stand productivities, and thus the absolute amount of nutrients removed. In addition to the impact of intensive harvesting, both sites are characterized by high seepage losses of base cations, further impairing the nutrient budget. While intensive biomass extraction causes detrimental effects on many key soil ecological properties, our calculations may serve to implement measures to improve the nutrient balance in forested ecosystems.
    Keywords: Spruce ; Pine ; Thinning ; Aboveground Biomass ; Energetic Use ; Stand Growth ; Nutrient Contents ; Nutrient Accumulation ; Forestry
    E-ISSN: 1999-4907
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  • 3
    Language: English
    In: Forests, 01 December 2016, Vol.8(1), p.19
    Description: The transport of nutrients in forest soils predominantly occurs along preferential flow pathways (PFP). This study investigated the composition of phosphorus (P) forms in PFPs and soil matrix in several temperate beech forests with contrasting soil P contents in Germany. The PFPs were visualized using dye tracer experiments. Stained and unstained soil was sampled from three profile cuts per plot and analyzed for P fractions. The results show that labile P concentrations were highest in the O-layer and had the same range of values at all sites (240–320 mg·kg−1), although total P (TP) differed considerably (530–2330 mg·kg−1). The ratio of labile P to TP was significantly lower in the P-rich soil compared to the medium and P-poor soils. By contrast, the ratio of moderately labile P to TP was highest at the P-rich site. The shifts in P fractions with soil depth were generally gradual in the P-rich soil, but more abrupt at the others. The contents of labile and moderately labile P clearly differed in PFPs compared to soil matrix, but not statistically significant. The studied soils are characterized by high stone contents with low potential for P sorption. However, indications were found that labile organically bound P accumulates in PFPs such as biopores.
    Keywords: Phosphorus Fractions ; Forest Soil ; Preferential Flow ; Pfp ; Forestry
    E-ISSN: 1999-4907
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  • 4
    Language: English
    In: Forests, 01 June 2015, Vol.6(6), pp.1949-1965
    Description: A major argument for incorporating deciduous tree species in coniferous forest stands is their role in the amelioration and stabilisation of biogeochemical cycles. Current forest management strategies in central Europe aim to increase the area of mixed stands. In order to formulate statements about the ecological effects of mixtures, studies at the stand level are necessary. In a mixed stand of Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) in the Ore Mountains (Saxony, Germany), the effects of these two tree species on chemical and microbial parameters in the topsoil were studied at one site in the form of a case study. Samples were taken from the O layer and A horizon in areas of the stand influenced by either birch, spruce or a mixture of birch and spruce. The microbial biomass, basal respiration, metabolic quotient, pH-value and the C and N contents and stocks were analysed in the horizons Of, Oh and A. Significantly higher contents of microbial N were observed in the Of and Oh horizons in the birch and in the spruce-birch strata than in the stratum containing only spruce. The same was found with respect to pH-values in the Of horizon and basal respiration in the Oh horizon. Compared to the spruce stratum, in the birch and spruce-birch strata, significantly lower values were found for the contents of organic C and total N in the A horizon. The findings of the case study indicated that single birch trees have significant effects on the chemical and microbial topsoil properties in spruce-dominated stands. Therefore, the admixture of birch in spruce stands may distinctly affect nutrient cycling and may also be relevant for soil carbon sequestration. Further studies of these functional aspects are recommended.
    Keywords: Birch ; Spruce ; Tree Species Effects ; Ph-Value ; Soil Respiration ; Humus ; Topsoil ; Forestry
    E-ISSN: 1999-4907
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  • 5
    Language: English
    In: Water, 01 December 2018, Vol.10(12), p.1862
    Description: Surface soil structure is sensitive to natural and anthropogenic impacts that alter soil hydraulic properties (SHP). These alterations have distinct consequences on the water cycle. In this review, we summarized published findings on the quantitative effects of different agricultural management practices on SHP and the subsequent response of the water balance components. Generally, immediately after tillage, soils show a high abundance of large pores, which are temporally unstable and collapse due to environmental factors like rainfall. Nevertheless, most hydrological modeling studies consider SHP as temporally constant when predicting the flow of water and solutes in the atmosphere-plant-soil system. There have been some developments in mathematical approaches to capture the temporal dynamics of soil pore space. We applied one such pore evolution model to two datasets to evaluate its suitability to predict soil pore space dynamics after disturbance. Lack of knowledge on how dispersion of pore size distribution behaves after tillage may have led to over-estimation of some values predicted by the model. Nevertheless, we found that the model predicted the evolution of soil pore space reasonably well (r2 〉 0.80 in most cases). The limiting factor to efficiently calibrate and apply such modeling tools is not in the theoretical part but rather the lack of adequate soil structural and hydrologic data.
    Keywords: Temporal Dynamics ; Soil Hydraulic Properties ; Soil Structure ; Tillage Effects ; Pore Size Distribution ; Engineering
    E-ISSN: 2073-4441
    Source: Directory of Open Access Journals (DOAJ)
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  • 6
    Language: English
    In: Forests, 01 December 2017, Vol.9(1), p.8
    Description: The objective of this study was to analyze patterns, dynamics and processes of land-use/cover changes in the transboundary Mara River Basin in East Africa. We specifically focused on deforestation and expansion of agriculture in the watershed. The intensity analysis approach was used to analyze data from satellite imagery-derived land-use/cover maps. Results indicate that swap change accounted for more than 50% of the overall change, which shows a very dynamic landscape transformation. Transition from closed forest to open forest was found to be a dominant landscape change, as opposed to a random change. Similarly, transition from open forest to small-scale agriculture was also found to be a dominant transition. This suggests a trend (pathway) of deforestation from closed forest to small-scale agriculture, with open forest as a transitional land cover. The observed deforestation may be attributed to continuous encroachment and a series of excisions of the forest reserve. Transition from rangeland to mechanized agriculture was found to be a dominant land-use change, which was attributed to change in land tenure. These findings are crucial for designing strategies and integrated watershed management policies to arrest further deforestation in the forest reserves as well as to sustainably control expansion of agriculture.
    Keywords: Land-Use Change ; Intensity Analysis ; Systematic Transition ; Deforestation ; Forestry
    E-ISSN: 1999-4907
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  • 7
    Language: English
    In: Forests, 01 June 2017, Vol.8(6), p.206
    Description: Phosphorus (P) export from forest soils is mainly driven by storm events, which induce rapid flow processes by preferential flow bypassing large parts of the soil matrix. However, little is known about the dynamics, magnitude, and driving processes of P exports into surface waters. In this paper, we present the results of a monitoring study in a small forested catchment (21 ha) situated in the low mountain ranges of Saxony, Germany. During the fixed schedule-sampling (weekly to bi-weekly sampling frequency for a three-year period), a mean total-P concentration of 8 μg·L−1 was measured. However, concentrations increased up to 203 μg·L−1 during individual storm flow events. Based on the analyzed concentrations and continuously measured discharge we calculated mean annual export rates of 19 to 44 g·ha−1·a−1 for the weekly sampling frequency with different load calculation methods. If events are included into the annual load calculation, the mean annual export fluxes can be up to 83 g·ha−1·a−1 based on the different load calculation methods. Predictions of total-P export rates based on a sampling strategy which does not consider short-term changes due to factors such as storms will substantially underestimate P exports.
    Keywords: Forested Catchments ; Phosphorus Exports ; Load Calculations ; Forestry
    E-ISSN: 1999-4907
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  • 8
    Language: English
    In: Revista Águas Subterrâneas, 01 January 2011
    Description: This study analysis the influences of reforestation measures on soil properties and water balance in semi-arid areas such as Northeastern Brazil. For an improved hydrological modeling innovative combinations of geophysical, remote sensing and digital soil mapping methods for the assessment of needed soil parameters will be applied.
    Keywords: Geography
    ISSN: 0101-7004
    E-ISSN: 2179-9784
    Source: Directory of Open Access Journals (DOAJ)
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  • 9
    Language: English
    In: Journal of Hydrology: Regional Studies, 01 March 2016, Vol.5, pp.244-260
    Description: Study region: Nyangores River watershed, headwater catchment of Mara River basin in Kenya. Study focus: Climate variability and human activities are the main drivers of change of watershed hydrology. The contribution of climate variability and land use change to change in streamflow of Nyangores River, was investigated. Mann Kendall and sequential Mann Kendall tests were used to investigate the presence and breakpoint of a trend in discharge data (1965–2007) respectively. The Budyko framework was used to separate the respective contribution of drivers to change in discharge. Future response of the watershed to climate change was predicted using the runoff sensitivity equation developed. New hydrological insights for the region: There was a significant increasing trend in the discharge with a breakpoint in 1977. Land use change was found to be the main driver of change in discharge accounting for 97.5% of the change. Climate variability only caused a net increase of the remaining 2.5% of the change; which was caused by counter impacts on discharge of increase in rainfall (increased discharge by 24%) and increase in potential evapotranspiration (decreased discharge by 21.5%). Climate change was predicted to cause a moderate 16% and 15% increase in streamflow in the next 20 and 50 years respectively. Change in discharge was specifically attributed to deforestation at the headwaters of the watershed. Keywords: Climate variability, Land use change, Hydrology, Streamflow, Water security, Budyko framework
    Keywords: Geography
    ISSN: 2214-5818
    E-ISSN: 2214-5818
    Source: Directory of Open Access Journals (DOAJ)
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  • 10
    Language: English
    In: Water, 01 August 2018, Vol.10(8), p.1021
    Description: Established measurement methods for hydraulic soil properties cover a limited soil moisture range. Simulations of soil water dynamics based on such observations are therefore rarely representative for all conditions from saturation to drought. Recent technical developments facilitate efficient and cheap collecting of soil water characteristics data, but the quantitative benefit of extended measurement campaigns has not been adequately tested yet. In this study, a combination of four methods to measure water retention and hydraulic conductivity at different moisture ranges was applied. Evaporation method, dewpoint psychrometry, hood infiltrometer experiments, and falling head method for saturated conductivity were conducted at two experimental sites in eastern Austria. Effects of including the particular methods in the measurement strategy were examined by visual evaluation and a 1D-modelling sensitivity study including drainage, infiltration and drought conditions. The evaporation method was considered essential due to its broad measurement range both for water retention and hydraulic conductivity. In addition to that, the highest effect on simulated water balance components was induced by the inclusion of separate conductivity measurements near saturation. Water content after three days of drainage was 15 percent higher and the transpiration rate in a drought period was 22 percent higher without near-saturated conductivity measurements. Based on relative comparisons between different combinations, we suggested combining evaporation method and hood infiltrometer experiments as the basis for representative predictions of soil water dynamics.
    Keywords: Hydraulic Soil Properties ; Soil Water Simulations ; Measurement Method Evaluation ; Functional Evaluation ; Engineering
    E-ISSN: 2073-4441
    Source: Directory of Open Access Journals (DOAJ)
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