Effect of fire frequency on runoff, soil erosion, and loss of organic matter at the micro-plot scale in north-central Portugal

Geoderma ◽  
2016 ◽  
Vol 269 ◽  
pp. 126-137 ◽  
Author(s):  
Mohammadreza Hosseini ◽  
Jan Jacob Keizer ◽  
Oscar Gonzalez Pelayo ◽  
Sergio Alegre Prats ◽  
Coen Ritsema ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Fire Frequency ◽  
North Central ◽  
Central Portugal

scholarly journals Analysis of Soil Erodibility Factor for Hydrologic Processes in Kereke Watershed, North Central Nigeria

2021 ◽  
Vol 25 (3) ◽  
pp. 425-432
Author(s):  
G.A. Songu ◽  
R.D. Abu ◽  
N.M. Temwa ◽  
S.T. Yiye ◽  
S. Wahab ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Bulk Density ◽  
Soil Management ◽  
Soil Samples ◽  
Hydrological Processes ◽  
Soil Erodibility ◽  
K Value ◽  
North Central ◽  
Soil Erodibility Factor

: Soil erodibility factor plays essential role in determining how susceptible soil is to hydrological processes such as detachment and removal by rainfall and runoff that could influence soil erosion and sediment entrainment by flooding in an area. This paper therefore determined the erodibility k-value of soil in the Kereke watershed with the purpose of assessing its susceptibility to hydrological processes. Data was collected on some soil properties such as soil texture, soil structure, soil organic matter content, soil carbon content, soil porosity, soil bulk density, soil moisture content and soil erodibility k-value. The systematic sampling procedure was used to select thirty-two settlements which served as catchment areas for data collection; from which thirty-two soil samples were collected for analysis. Tables and graph were used to present the data, and percentages were used to depict variations in the data set. Results of the study shows that the soil samples have high percent sand particles (71.6%), moderate amount of clay particles (15.7%), silt(12.7%), organic carbon (0.6%), organic matter (1.1%), bulk density (1.4 gcm-3 ), porosity (45.2%), moisture content (14.0%) and low soil erodibility k-value of 0.018. The soil erodibility k-value in the study area was considered to be low, and therefore the soils are moderately erodible. This probably accounts for the moderate intensity of soil erosion channels and entrained sediments by flooding observed in the study area. It is therefore recommended that soil management practices should be encouraged by farmers especially planting of cover crops, shifting cultivation and fallowing system. This will allow nutrients gain and improved bulk density to limit soil erodibility capacity and good soil management in the area. Key words: Soil erodibility factor, hydrological processes, Kereke watershed, North Central Nigeria

scholarly journals A Quantitative Analysis of Factors Influencing Organic Matter Concentration in the Topsoil of Black Soil in Northeast China Based on Spatial Heterogeneous Patterns

2021 ◽  
Vol 10 (5) ◽  
pp. 348
Author(s):  
Zhenbo Du ◽  
Bingbo Gao ◽  
Cong Ou ◽  
Zhenrong Du ◽  
Jianyu Yang ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Erosion ◽  
Soil Type ◽  
Northeast China ◽  
Black Soil ◽  
Factors Affecting ◽  
Soil Zone ◽  
Rainfed Farming ◽  
Study Results

Black soil is fertile, abundant with organic matter (OM) and is exceptional for farming. The black soil zone in northeast China is the third-largest black soil zone globally and produces a quarter of China’s commodity grain. However, the soil organic matter (SOM) in this zone is declining, and the quality of cultivated land is falling off rapidly due to overexploitation and unsustainable management practices. To help develop an integrated protection strategy for black soil, this study aimed to identify the primary factors contributing to SOM degradation. The geographic detector, which can detect both linear and nonlinear relationships and the interactions based on spatial heterogeneous patterns, was used to quantitatively analyze the natural and anthropogenic factors affecting SOM concentration in northeast China. In descending order, the nine factors affecting SOM are temperature, gross domestic product (GDP), elevation, population, soil type, precipitation, soil erosion, land use, and geomorphology. The influence of all factors is significant, and the interaction of any two factors enhances their impact. The SOM concentration decreases with increased temperature, population, soil erosion, elevation and terrain undulation. SOM rises with increased precipitation, initially decreases with increasing GDP but then increases, and varies by soil type and land use. Conclusions about detailed impacts are presented in this paper. For example, wind erosion has a more significant effect than water erosion, and irrigated land has a lower SOM content than dry land. Based on the study results, protection measures, including conservation tillage, farmland shelterbelts, cross-slope ridges, terraces, and rainfed farming are recommended. The conversion of high-quality farmland to non-farm uses should be prohibited.

RESTORING PRODUCTIVITY TO AN ARTIFICIALLY ERODED DARK BROWN CHERNOZEMIC SOIL UNDER DRYLAND CONDITIONS

1986 ◽  
Vol 66 (2) ◽  
pp. 273-285 ◽  
Author(s):  
J. F. DORMAAR ◽  
C. W. LINDWALL ◽  
G. C. KOZUB
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Green Manure ◽  
Soil Structure ◽  
Management Practices ◽  
Fertilizer Application ◽  
Sweet Clover ◽  
Yield Losses ◽  
Critical Factors ◽  
Structure Characteristics

A field was artificially eroded by levelling in 1957 and then continuously cropped to barley for 7 yr. Subsequently, a wheat-fallow experiment was conducted from 1965 to 1979 to determine the effects of four fertilizer treatments and green manure (yellow sweet clover) on restoring the productivity to soil that had been "eroded" to various depths. After 22 yr and 14 crops, the productivity of the land from which soil was removed has been improved but not fully restored. Although green manuring with yellow sweet clover improved soil structure, wheat yields were not improved because of competition for soil moisture and poorer in-crop weed control in this part of the rotation. The addition of 45 kg N plus 90 kg P2O5 per hectare in each crop year to sites from which 8–10, 10–20, or 46 + cm of soil had been removed resulted in yield increases of 18, 46, and 70%, respectively, over the unfertilized check of each treatment; the average yields were 104, 91, and 70%, respectively, of the undisturbed, unfertilized (check) treatment. On "erosion" treatments where only 8–10 cm of soil were removed, 45 kg N plus 22 kg P2O5 per hectare were sufficient to restore the productivity. Precipitation apparently had a greater effect than fertilizer application on wheat yields. The loss of organic matter and associated soil structure characteristics seemed to be critical factors contributing to yield losses associated with soil erosion. These results show that it is more practical to use management practices that prevent soil erosion than to adopt the practices required to restore eroded soil. Key words: Soil erosion, topsoil loss, water-stable aggregates, soil organic matter, green manure, precipitation

The nodular granite of Castanheira, north central Portugal: origin of the nodules and evidence for diapiric mobilization of granite

1993 ◽  
Vol 130 (2) ◽  
pp. 145-153 ◽  
Author(s):  
R. J. Reavy ◽  
D. H. W. Hutton ◽  
A. A. Finch
Keyword(s):  
Chemical Potential ◽  
Structural Data ◽  
Vapour Phase ◽  
Vapour Bubble ◽  
North Central ◽  
Host Granite ◽  
Low Viscosity ◽  
Granite Body ◽  
Central Portugal ◽  
Strong Depletion

AbstractThe Castanheira pluton in north-central Portugal is a small (1000 m × 600 m) granite body of Hercynian age which contains a remarkable abundance of granite-cored, biotite-rimmed nodules. The nodules are interpreted as representing original bubbles in the uppermost volatile-rich zone of a granitic pluton. Strong depletion in K and Rb in the host granite around the nodules suggests that the biotite is magmatic in origin. The nodules may have formed by reaction between chloroferrate(II) complexes in the vapour phase and silicate melt, possibly followed by condensation of the vapour phase to a small granitic core. Motion of the vapour bubble stabilized a gradient in chemical potential with respect to the host granite, giving rise to the nodules. Chemical, petrological and structural data suggest that the pluton was part of a larger granite body, which was forcefully emplaced during synchronous transcurrent shearing. The inferred presence of volatiles, in addition to the pervasive tourmalinization of the roof zone, suggest that the magma was halogen-rich; this may imply that the magma had low viscosity.

Post-fire mobilization of metals in a recently burnt area in North-Central Portugal: a contamination risk for waterbodies?

2021 ◽  
Author(s):  
Dalila Serpa ◽  
Ana Machado ◽  
Martha Santos ◽  
Isabel Campos ◽  
Fátima Jesus ◽  
...  
Keyword(s):  
Overland Flow ◽  
Fire Severity ◽  
Hazardous Substances ◽  
Burnt Area ◽  
North Central ◽  
Contamination Risk ◽  
Freshwater Bodies ◽  
Central Portugal ◽  
Study Sites

<p>Wildfires constitute a diffuse source of contamination to aquatic ecosystems. In burnt hillslopes, ash and sediments transported by overland flow are a source of potentially hazardous substances, like metals, posing a risk for downstream water bodies. In the present study, post-fire metal mobilization by overland flow was evaluated in 16 m<sup>2 </sup>bounded plots at a eucalypt stand in Albergaria-a-Velha (Aveiro district, North-Central Portugal) that burnt with moderate severity in September 2019. Overland flow samples were collected on a weekly to bi-weekly basis, depending on the occurrence of rain, during the first 6 months after fire. Aside from overland flow samples collected at slope scale, water and sediment samples were also collected in a fire-affected stream within the Albergaria burned catchment, to assess the contamination risk posed by the fire. Samples were collected at three sites along the stream: one upstream, one within and another downstream from the burnt area, after major rainfall events. The metals analysed in this study included, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). Results showed that most metals exhibited a peak in exports immediately after the first significant post-fire rainfall event likely due to the wash-off of the ash layer and high sediment losses, but for some elements like Zn and Cu, exports were more or less constant over time. The fire seems to have had a low impact on the water quality of the affected stream, since metal concentrations were similar between the three study sites. The quality of stream sediments, on the other hand, was clearly affected by the fire, especially after the rainy season. As fire severity and frequency is forecasted to increase in the near future due to climate changes, the results of this work reinforce the importance of water managers to define adaptative strategies to effectively protect freshwater bodies.</p>

scholarly journals Soil degradation: a problem threatening the sustainable development of agriculture in Northeast China

2010 ◽  
Vol 56 (No. 2) ◽  
pp. 87-97 ◽  
Author(s):  
X.B. Liu ◽  
X.Y. Zhang ◽  
Y.X. Wang ◽  
Y.Y. Sui ◽  
S.L. Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Erosion ◽  
Environmental Sustainability ◽  
Northeast China ◽  
Soil Degradation ◽  
Soil Layer ◽  
Organic Matter Content ◽  
Distribution Area ◽  
Grain Production

Soil degradation that results from erosion, losses of organic matter and nutrients, or soil compaction are of great concern in every agricultural region of the world. The control of soil erosion and loss of organic matter has been proposed as critical to agricultural and environmental sustainability of Northeast China. This region is bread basket of China where the fertile and productive soils, Mollisols (also called Black soils), are primarily distributed. In this paper, we introduce the importance of Northeast China’s grain production to China, and describe the changes of sown acreage and grain production in past decades. This paper also summarizes the distribution, area and intensity of water erosion, changes in the number of gullies and gully density, thickness of top soil layer, soil organic matter content, bulk density, field water holding capacity, and infiltration rates; the number of soil microorganism and main enzyme activities from soil erosion in the region are also summarized. The moderately and severely water-eroded area accounted for 31.4% and 7.9% of the total, and annual declining rate is 1.8%. Erosion rate is 1.24–2.41 mm/year, and soil loss in 1°, 5° and 15° sloping farmlands is 3 t/ha/year, 78 t/ha/year and 220.5 t/ha/year, respectively. SOC content of uncultivated soil was nearly twice that of soil with a 50-year cultivation history, and the average annual declining rate of soil organic matter was 0.5%. Proper adoption of crop rotation can increase or maintain the quantity and quality of soil organic matter, and improve soil chemical and physical properties. Proposed strategies for erosion control, in particular how tillage management, terraces and strip cultivation, or soil amendments contribute to maintain or restore the productivity of severely eroded farmland, are discussed in the context of agricultural sustainability with an emphasis on the Chinese Mollisols.

scholarly journals Radiocarbon Dating of Total Soil Organic Matter and Humin Fraction and Its Comparison with 14C Ages of Fossil Charcoal

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 595-601 ◽  
Author(s):  
L C R Pessenda ◽  
S E M Gouveia ◽  
R Aravena
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Radiocarbon Dating ◽  
Natural Vegetation ◽  
Soil Profiles ◽  
North Central ◽  
Total Soil ◽  
Experimental Errors ◽  
Humin Fraction

During the last decade radiocarbon dating has been used extensively in distinct regions of Brazil to provide information about soil chronology in paleoenvironmental studies. This paper presents 14C data of soil organic matter (SOM), humin fraction, and charcoal in several soil profiles under natural vegetation from different Brazil locations (north, central, and southeast regions). The main objective is to compare the obtained 14C dating of total SOM with humin, the oldest fraction of SOM. In order to validate the humin ages these data are compared with the age of charcoal collected at similar depths. The 14C ages obtained on charcoal were, in most of the cases, in agreement with the humin fraction considering the experimental errors, or 20% older in average. The dates obtained from total SOM showed significantly younger ages than the humin fraction indicating contamination by younger carbon. These results show the humin fraction is considered a reliable material for 14C dating in soils. However, the humin fraction ages could be assumed as the minimum ages for carbon in soils.

The Impact of Plant Hedgerow in Three Gorges on the Soil Chemicophysical Properties and Soil Erosion

2012 ◽  
Vol 500 ◽  
pp. 142-148 ◽  
Author(s):  
Wen Xing Lü ◽  
Hong Jiang Zhang ◽  
Yu He Wu ◽  
Jin Hua Cheng ◽  
Jian Qiang Li ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Citrus Reticulata ◽  
Three Gorges ◽  
Zanthoxylum Bungeanum ◽  
The Impact ◽  
Nitrogen Phosphorus

Through the research and sampling analysis on different plant hedgerow in sloped farmland in Three Gorges reservoir area, we will conduct research on the impact of plant hedgerow in Three Gorges on the chemicophysical properties of soil and soil erosion. The results show that the plant hedgerow mainly composed by Morus alba, Citrus reticulata, Zanthoxylum bungeanum, Vitex negundoand Begonia fimbristipula can decrease the soil density as well as sand content and increase soil porosity, soil water content, silt content and clay content to some extent. The organic matter, nitrogen, phosphorus, potassium and cation exchange capacity and other chemical indices of soil in different locations in plant hedgerow indicate as maximum in on-band, minimum in inter-band, middle both upper-band and below-band. In the same slop with no plant hedgerow, the organic matter, nitrogen, phosphorus, potassium and cation exchange capacity and other chemical indices of soil show a trend of increasing from the top to the bottom of the slop, which reveals that these substances own a feature of accumulation by moving to the bottom. The strength of soil anti-corrosion in different plant hedgerow is: Vitex negundoand (79.2%)> Citrus reticulata (36.4%)> Morus alb (22.4%)> Zanthoxylum bungeanum (18.9%)> Begonia fimbristipula (15.3%)> CK (8.7%), and the soil anti-corrosion indices in plant hedgerow are decreasing with the increase of soil immersion time, besides, the former and the latter are 3 times polynomial function. For those 5 plant hedgerows, Vitex negundoand owns the best impact on improving soil chemicophysical properties and reducing soil erosion.

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