scholarly journals Natural 15N abundance in two nitrogen saturated forest ecosystems at Solling, Germany

2012 ◽  
Vol 49 (No. 11) ◽  
pp. 515-522 ◽  
Author(s):  
S. P Sah ◽  
R. Brumme
Keyword(s):  
Soil Water ◽  
Soil Depth ◽  
Mineral Soil ◽  
Soil Layer ◽  
Organic Soil ◽  
Soil Horizon ◽  
Nitrification Rate ◽  
Seepage Water ◽  
Natural Occurrence ◽  
N Enrichment

This research deals with a comparative study of two different N-saturated forests: 1. beech forest and 2. spruce forest at the same locality of \solling, Central Germany. The present results show that <sup>15</sup>N natural occurrence in the rainfall (both above and below canopy) at Solling site is similar (&delta;<sup>15</sup>N = &ndash;15&permil; to +19&permil;) to other sites of the world (such as NITREX sites, USA etc.). Furthermore, <sup>15</sup>N values in the soil water ranged from &ndash;4.32 (&plusmn; 2.09) to +5&permil; (&plusmn; 1.47), which also corresponds to NITREX sites and other sites of Europe and USA. In both forests, &delta;<sup>15</sup>N enrichment of both NH<sub>4</sub>-N and NO<sub>3</sub>-N showed a decreasing trend of their values from bulk precipitation to the upper soil layer, but increasing in the deeper soil layer again. An increase in the <sup>15</sup>N enrichment of soil water from upper soil depth to lower soil depth was observed in our study and it is assumed to be due to the strong net nitrification taking place in the upper layer (organic surface layer) of soil. The soils at both sites showed characteristic low (negative) &delta;<sup>15</sup>N values in the upper organic layers, strongly increasing to positive &delta;<sup>15</sup>N values in the mineral soil. In the lower depths of mineral soil horizons of both stands, an increase in &delta;<sup>15</sup>N values was found to culminate at +3 to +5&permil;. In contrast to the mineral soil horizon, in the organic soil horizon (0 to 6 cm depth) of both sites there was almost a similar or slight decrease in &delta;<sup>15</sup>N values with depth. This is attributed to the high nitrification rate in the organic soil horizon, resulting in excessive seepage water NO<sub>3</sub>-output at both sites (especially at the spruce site).

The effects of afforestation on Fe mobilization in soils and potential for leaking into surface waters

2020 ◽  
Author(s):  
Martin Škerlep ◽  
Ulf Johansson ◽  
Dan Berggren Kleja ◽  
Per Persson ◽  
Emma S Kritzberg
Keyword(s):  
Soil Water ◽  
Northern Hemisphere ◽  
Surface Waters ◽  
Mineral Soil ◽  
Coniferous Forest ◽  
Organic Soil ◽  
Soil Horizon ◽  
Societal Implications ◽  
Spruce Stands ◽  
Fe Speciation

&lt;p&gt;Increasing surface water concentrations of Fe and DOC (browning), have been reported around the northern hemisphere in the last couple of decades. This increase has far-reaching ecological and societal implications, as it alters the light climate in water and decreases the quality of drinking water. One of the hypothesis behind the increase has been that afforestation and a dominance of coniferous forest have increased the availability of Fe and DOC for transport from soils into surface waters. The accumulation of organic soil layers in coniferous forests increases acidity and the amounts of organic acids in soils and may thus enhance weathering, solubility and mobilization of Fe as the forest ages. In this study we examined the effects of afforestation and growth of Norway spruce on the mobilization and potential leakage of Fe and DOC from soils to surface waters. To represent the effects of ageing forest we used plots with spruce stands of different ages (35, 61, 90 years) and unforested control plots in their immediate proximity, in T&amp;#246;nnersj&amp;#246;heden experimental forest (Sweden). Soil water collected in lysimeters (installed below the organic horizon and in the mineral soil) and analyzed for Fe, Fe speciation, using X-ray absorption spectroscopy (XAS), as well as DOC, metals, major anions and cations. Soil samples were analyzed for Fe speciation and crystallinity at different depths. Results from the soil water analysis show that more Fe was mobile in older spruce forest stands with higher DOC concentrations and lower pH. Covariation of Fe and DOC concentrations in soil waters, indicate the dependence of Fe on DOC to solubilize and stay in solution. Preliminary results from our XAS analysis also indelicate a considerable amount of Fe(II) in soil water that is likely stabilized from oxidation by organic complexation. Surprisingly Fe extracted from the organic (O) soil horizon showed the highest crystallinity and crystallinity did not vary much between soils of different stand ages. &amp;#160;The results of this study indicate that afforestation promotes Fe and DOC availability for export into surface waters as well as strengthens the notion that the effects of afforestation are not immediate, but take time as soils develop slowly. As afforestation and dominance of coniferous forest continues in many parts of the northern hemisphere, we can expect further increase of Fe and DOC in surface waters.&lt;/p&gt;

scholarly journals Effects of different biomass materials as a salt-isolation layer on water and salt migration in coastal saline soil

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11766
Author(s):  
Mao Yang ◽  
Runya Yang ◽  
Yanni Li ◽  
Yinghua Pan ◽  
Junna Sun ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Salt Concentration ◽  
Saline Soil ◽  
Soil Depth ◽  
Soil Layer ◽  
Thick Layer ◽  
Peat Layer ◽  
Salt Accumulation

The aim of this study was to find a material suited for the prevention of evaporative water loss and salt accumulation in coastal saline soils. One-dimensional vertical water infiltration and phreatic evaporation experiments were conducted using a silty loam saline soil. A 3-cm-thick layer of corn straw, biochar, and peat was buried at the soil depth of 20 cm, and a 6-cm-thick layer of peat was also buried at the same soil depth for comparison. The presence of the biochar layer increased the upper soil water content, but its ability to inhibit salt accumulation was poor, leading to a high salt concentration in the surface soil. The 3-cm-thick straw and 6-cm-thick peat layers were most effective to inhibit salt accumulation, which reduced the upper soil salt concentration by 96% and 93%, respectively. However, the straw layer strongly inhibited phreatic evaporation and resulted in low water content in the upper soil layer. Compared with the straw layer, the peat layer increased the upper soil water content. Thus, burying a 6-cm-thick peat layer in the coastal saline soil is the optimal strategy to retain water in the upper soil layer and intercept salt in the deeper soil layer.

A regionally explicit, global SWI calibration based on ISMN observations

2021 ◽  
Author(s):  
Manolis G. Grillakis
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Large Scale ◽  
Root Zone ◽  
Soil Depth ◽  
European Space Agency ◽  
Soil Layer ◽  
Added Value ◽  
Water Index ◽  
Soil Moisture Data

&lt;p&gt;Remote sensing has proven to be an irreplaceable tool for monitoring soil moisture. The European Space Agency (ESA), through the Climate Change Initiative (CCI), has provided one of the most substantial contributions in the soil water monitoring, with almost 4 decades of global satellite derived and homogenized soil moisture data for the uppermost soil layer. Yet, due to the inherent limitations of many of the remote sensors, only a limited soil depth can be monitored. To enable the assessment of the deeper soil layer moisture from surface remotely sensed products, the Soil Water Index (SWI) has been established as a convolutive transformation of the surface soil moisture estimation, under the assumption of uniform hydraulic conductivity and the absence of transpiration. The SWI uses a single calibration parameter, the T-value, to modify its response over time.&lt;/p&gt;&lt;p&gt;Here the Soil Water Index (SWI) is calibrated using ESA CCI soil moisture against in situ observations from the International Soil Moisture Network and then use Artificial Neural Networks (ANNs) to find the best physical soil, climate, and vegetation descriptors at a global scale to regionalize the calibration of the T-value. The calibration is then used to assess a root zone related soil moisture for the period 2001 &amp;#8211; 2018.&lt;/p&gt;&lt;p&gt;The results are compared against the European Centre for Medium-Range Weather Forecasts, ERA5 Land reanalysis soil moisture dataset, showing a good agreement, mainly over mid-latitudes. The results indicate that there is added value to the results of the machine learning calibration, comparing to the uniform T-value. This work contributes to the exploitation of ESA CCI soil moisture data, while the produced data can support large scale soil moisture related studies.&lt;/p&gt;

Viable seed populations by soil depth and potential site recolonization after disturbance

1977 ◽  
Vol 55 (18) ◽  
pp. 2408-2412 ◽  
Author(s):  
Janice M. Moore ◽  
Ross W. Wein
Keyword(s):  
Soil Depth ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Organic Soil ◽  
Viable Seed ◽  
Soil Layers ◽  
Forest Experiment Station ◽  
Viable Seeds ◽  
Study Sites ◽  
Germination Experiment

Seedling emergence from organic and mineral soil layers was measured for nine study sites at the Acadia Forest Experiment Station near Fredericton, New Brunswick. The number of viable seeds showed a decrease from deciduous-dominated forest, to conifer-dominated forest, to organic soil study sites. Viable seed number varied from 3400/m2 for a deciduous-dominated forest study site to zero for a bog study site. Most seeds germinated from the upper organic soil layers of all study sites and were predominantly Rubus strigosus Michx. After the germination experiment, ungerminated seeds, which showed no viability by the tetrazolium test, were separated from the soil. These seeds were almost entirely Betula spp. and seed numbers were as high as 4200–9400/m2 for a deciduous-dominated forest. The applicability of the results to differing types of postdisturbance revegetation is discussed.

Hypholoma lateritiumisolated from coarse woody debris, the forest floor, and mineral soil in a deciduous forest in New Hampshire

Botany ◽  
2012 ◽  
Vol 90 (6) ◽  
pp. 457-464 ◽  
Author(s):  
Therese A. Thompson ◽  
R. Greg Thorn ◽  
Kevin T. Smith
Keyword(s):  
New Hampshire ◽  
Deciduous Forest ◽  
Repetitive Sequences ◽  
Mineral Soil ◽  
Acer Rubrum ◽  
Organic Soil ◽  
Nuclear Ribosomal Dna ◽  
Soil Horizon ◽  
Soil Horizons ◽  
Internal Transcribed Spacer Region

Fungi in the Agaricomycetes (Basidiomycota) are the primary decomposers in temperate forests of dead wood on and in the forest soil. Through the use of isolation techniques selective for saprotrophic Agaricomycetes, a variety of wood decay fungi were isolated from a northern hardwood stand in the Bartlett Experimental Forest, New Hampshire, USA. In particular, Hypholoma lateritium (Schaeff.: Fr.) P. Kumm. was isolated from basidiocarps, decaying Acer rubrum L. logs, the Oe organic soil horizon, and the E and BC mineral soil horizons. Identification was confirmed by sequence analysis of the internal transcribed spacer region of nuclear ribosomal DNA. All isolates had identical sequences in this region to previously published sequences for the species; some were monokaryotic and simple-septate and others were dikaryotic, with clamp connections. Isolates were further characterized by banding patterns (DNA fingerprints) produced with PCR primers based in simple repetitive sequences and the minisatellite M13. Nine dikaryotic isolates from basidiocarps and from soil horizons Oe, E, and BC had identical fingerprint patterns with all primers tested. The confirmed presence of H. lateritium suggests that this fungus could form a mycelial translocation network that bridges mineral and organic soil horizons and decaying logs.

scholarly journals Quantity and distribution of fine root biomass in the intermediate stage of beech virgin forest Badínsky prales

2009 ◽  
Vol 55 (No. 11) ◽  
pp. 502-510 ◽  
Author(s):  
P. Jaloviar ◽  
L. Bakošová ◽  
S. Kucbel ◽  
J. Vencurik
Keyword(s):  
Root Length ◽  
Root Biomass ◽  
Fine Root ◽  
Soil Depth ◽  
Mineral Soil ◽  
Soil Layer ◽  
Intermediate Stage ◽  
Fine Root Biomass ◽  
Virgin Forest ◽  
Fine Root Length

The fine root biomass represents 3,372 kg/ha in the intermediate stage of the beech virgin forest with different admixture of goat willow, where the vast majority of this biomass is located in the uppermost mineral soil layer 0–10 cm. The variability of the fine root biomass calculated from 35 sample points represents approximately 90% of the mean value and reaches the highest value within the humus layer. The total fine root length investigated in 10 cm thick soil layers decreases with increasing soil depth. A significant linear relationship between the fine root length (calculated per 1 cm thick soil layer and 1 m<sup>2</sup> of stand area) and the soil depth was confirmed, although the correlation is rather weak. The number of root tips decreases with increasing soil depth faster than the root length. As the number of tips per 1 cm of root length remains in the finest diameter class without significant changes, the reason is above all a decreased proportion of the finest root class (diameter up to 0.5 mm) from the total fine root length within the particular soil layer.

scholarly journals The Depth of Water Taken up by Walnut Trees during Different Phenological Stages in an Irrigated Arid Hilly Area in the Taihang Mountains

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 121 ◽  
Author(s):  
Yang Liu ◽  
Xuemei Zhang ◽  
Shuang Zhao ◽  
Huabing Ma ◽  
Guohui Qi ◽  
...  
Keyword(s):  
Soil Water ◽  
Soil Depth ◽  
Isotope Composition ◽  
Irrigation Management ◽  
Soil Layer ◽  
Root Water Uptake ◽  
Phenological Stages ◽  
Hilly Area ◽  
Fruit Maturity ◽  
Hydrogen And Oxygen Isotope

Understanding how the soil environment impacts root water uptake location and magnitude is important for better management of plant irrigation. In this study, stable hydrogen and oxygen isotope composition were used to determine seasonal variations in the depth of water taken up by walnut trees during different phenological stages in an irrigated arid hilly area in the Taihang Mountains in China. The contributions of soil water at different depths to the water taken up were quantified by the MixSIAR Bayesian isotope mixing model. The results indicated that water taken up by the walnut trees was sourced mainly from soil water in the 0–20 cm soil layer at the sprouting and leaf expansion stages (62.95%), and the 20–40 cm soil layer at blossoming and fruit-bearing (43.45%), fruit expansion (41.8%), and fruit maturity (39.15%) stages. The mean soil depth of the water taken up by the walnut trees gradually decreased as the phenological stages advanced. The proportions of various soil layer water contributions to the walnut trees differed throughout the phenological stages, and the proportion of deeper soil water contributions gradually increased as the phenological stages of walnut trees advanced. The results of the present study indicated that water sources for walnut trees varied by depth during different phenological stages. In addition to soil moisture, soil temperature may also be an important factor affecting the depth of water taken up by walnut trees. The results also provided scientific implications for water-saving irrigation management.

scholarly journals Water Stable Isotopes in an Alpine Setting of the Northeastern Tibetan Plateau

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 770 ◽  
Author(s):  
Xue Qiu ◽  
Mingjun Zhang ◽  
Shengjie Wang ◽  
Athanassios A. Argiriou ◽  
Rong Chen ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Water Cycle ◽  
Soil Depth ◽  
Soil Layer ◽  
Water Source ◽  
Hydrological Processes ◽  
Deep Soil ◽  
Monthly Basis ◽  
Mountainous Regions

Hydrological processes produce effects on water resources in inland mountainous regions. To perform a comprehensive investigation of the important segments of the water cycle, using the Qilian Mountains as a case study, precipitation, soil, plant, river, and groundwater were collected during the plant growing season of 2016. All samples were collected on a monthly basis, except precipitation, which was collected on a per event basis. The results showed that: the “temperature effect” was apparent, which suggested a drier climate background; there were differences in the slope and intercept of the local meteoric water line, using different regression methods; and the δ18O of soil water varied greatly in the topsoil, tended to be similar in the deep soil, and became increasingly depleted as the soil depth increased. The responses of the soil water isotopes to precipitation pulses had different boundaries. The major water source for Caragana Fabr. in no-precipitation month was located in the 0–30 cm soil layer, but was different in months when precipitation occurred. Overall, the findings from the stable isotopes provide insights into hydrological processes and offer a platform to understand mountainous water cycle in arid areas.

scholarly journals Experimental Study of the Effect of Controlled Drainage on Soil Water and Nitrogen Balance

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2241
Author(s):  
Niannian Yuan ◽  
Yujiang Xiong ◽  
Yalong Li ◽  
Baokun Xu ◽  
Fengli Liu
Keyword(s):  
Soil Moisture ◽  
Water Level ◽  
Soil Water ◽  
Nitrogen Balance ◽  
Field Experiments ◽  
Soil Depth ◽  
Soil Layer ◽  
Ammonia Nitrogen ◽  
Soil Water Storage ◽  
Control Water

Field experiments and micro test pit experiments are conducted at the Four Lake Watershed with a shallow groundwater table in the Hubei province of China in order to study the effect of controlled pipe drainage on soil moisture and nitrogen under different experiment scales. Soil moisture and nitrogen contents are continuously observed at the effective soil depth; water and nitrogen balance are calculated after several heavy rainfalls. The results showed that controlled pipe drainage significantly reduced the fluctuation of soil water content in the entire growth stage. There is a positive correlation between the soil moisture and the control water level in the test pits but no obvious correlation between them in the field experiments, which is related to the vertical and lateral recharge of groundwater in the field. After rainfall, soil organic matter mineralization was enhanced, and the control pipe drainage measures increased the relative content of soil mineralized ammonia nitrogen, which enhanced the stability of soil nitrogen and helped to reduce the loss of nitrogen. The calculation of soil water and nitrogen balance in the field and micro-area after rainfall showed that the soil water storage increased in the effective soil layer under the control water level of 30 cm and 50 cm after rainfall, and the amount of nitrogen mineralization was larger than that under the free drainage treatment.

scholarly journals Soil-water characteristic curves for collapsing walls of Benggang in a typical granite area of southeast China

2021 ◽  
Author(s):  
Liting Zhang ◽  
Shujun Sun ◽  
Mengqi Lin ◽  
Kaijun Feng ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Depth ◽  
Characteristic Curve ◽  
Soil Layer ◽  
Particle Morphology ◽  
Red Soil ◽  
Southeast China ◽  
Average Value ◽  
Water Holding

The water content is a crucial factor in evaluating the causes of Benggang collapse. The soil–water characteristic curve (SWCC) is an important parameter for the quantitative study of soil water content. However, limited research has been carried out on the SWCCs of the Benggang soil profile. We studied two typical collapsing gullies in southeast China and conducted desorption experiments using a pressure plate extractor to analyze the SWCCs of the undisturbed soils of collapsing walls. The results show large variations in the SWCCs for different soil horizons of a collapsing wall that can be accurately fitted by the van Genuchten (VG) model (NSE≥0.90). With increasing soil depth, the a and θs parameters of the VG model first decrease and then increase, red soil layer had the highest a and θs (the average value of 0.046 and 0.369, respectively), whereas the n parameter of the VG model exhibits the opposite trend, sand soil layer had the highest n (the average value of 1.563). The θr parameter of the VG model decreases with increasing soil depth, red soil layer had the highest θr (the average value of 0.194). The red soil layer has the highest water-holding capacity, whereas the sandy soil and detritus layers have lower water-holding capacities. The SWCCs are related to the soil material composition, particle composition and porosity. The gravel content and the particle morphology (the aspect ratio, sphericity, and specific surface area) are also the significant influence factors for the SWCC that cannot be neglected. The difference among the SWCCs for the soil profiles of collapsing walls can be used to explain the mechanism for the collapse of collapsing wall. The results of this study provide a theoretical basis for understanding the process of the collapse of collapsing wall in Benggang in southeast China.

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