scholarly journals The Role of Unpaved Roads in The Sediment Budget of A Semi‐Arid Mesoscale Catchment

2021 ◽  
Author(s):  
Teresa Raquel Lima Farias ◽  
Pedro Henrique Augusto Medeiros ◽  
José Carlos Araújo ◽  
Joaquín Navarro‐Hevia
Keyword(s):  
Sediment Budget ◽  
Unpaved Roads ◽  
Semi Arid

Carbon mineralization in semi-arid northeastern Australia: the role of termites

1987 ◽  
Vol 3 (3) ◽  
pp. 255-263 ◽  
Author(s):  
John A. Holt
Keyword(s):  
Regression Analysis ◽  
Carbon Flux ◽  
Microbial Population ◽  
Carbon Mineralization ◽  
Termite Mounds ◽  
Interaction Term ◽  
Temperature Interaction ◽  
Soil Carbon Mineralization ◽  
Semi Arid

ABSTRACTThe contribution of a population of mound building, detritivorous termites (Amitermes laurensis (Mjöberg)) to nett carbon mineralization in an Australian tropical semi-arid woodland has been examined. Carbon mineralization rates were estimated by measuring daily CO2 flux from five termite mounds at monthly intervals for 12 months. Carbon flux from the mounds was found to be due to microbial activity as well as termite activity. It is conservatively estimated that the association of A. laurensis and the microbial population present in their mounds is responsible for between 4%–10% of carbon mineralized in this ecosystem, and the contribution of all termites together (mound builders and subterranean) may account for up to 20% of carbon mineralized. Regression analysis showed that rates of carbon mineralization in termite mounds were significantly related to mound moisture and mound temperature. Soil moisture was the most important factor in soil carbon mineralization, with temperature and a moisture X temperature interaction term also exerting significant affects.

Non-crop resources and the role of indigenous knowledge in semi-arid production of Mexico

2007 ◽  
Vol 119 (1-2) ◽  
pp. 39-48 ◽  
Author(s):  
Isabelle Blanckaert ◽  
Koenraad Vancraeynest ◽  
Rony L. Swennen ◽  
Francisco J. Espinosa-García ◽  
Daniel Piñero ◽  
...  
Keyword(s):  
Indigenous Knowledge ◽  
Semi Arid

scholarly journals The role of unpaved roads in the formation of landslide processes (on the example of Voronezh region)

2020 ◽  
Vol 28 (1) ◽  
pp. 65-74
Author(s):  
Andrey N. Timofeev
Keyword(s):  
Soil Layer ◽  
Anthropogenic Activity ◽  
Unpaved Roads ◽  
Erosion Processes ◽  
Voronezh Region ◽  
Landslide Processes ◽  
Landslide Process ◽  
The Impact ◽  
Landslide Distribution

The article gives a brief description of the Voronezh region, provides data on the cause of landslides in its territory. The cyclical nature of landslide processes is noted, which in the region is on average 6-8 years. Attention is focused on anthropogenic activity, leading to the occurrence of creeping layers of the earth. The main causes of erosion processes are: significant plowing of the area (80%), which is not subject to the rules of anti-erosion agrotechnology; the irrational use of pastures and hayfields; an extensive gully-beam network. The role of temporary reservoirs formed in the ruts of unpaved roads, passing along the slopes and ravines, as a source of overmoistening of the soil layers and initiation of landslide processes is considered. The analysis of the landslide distribution over the territory of the Voronezh region and their dependence on the network of dirt roads is given. The areas of the Voronezh region were ranked by the number of landslide processes associated with the impact of a number of unpaved highways. Of the 32 districts of the region, according to this ranking, 12 are extremely dangerous, very dangerous and dangerous, and the same areas have a very extensive network of unpaved roads running near ravines, steep banks of rivers and ponds, where potentially flow of landslide processes. Dirt roads often have relatively deep ruts where melted or rainwater accumulates, forming local micro-ponds. Flowing to the waterproof layer, water saturates the soil layer, which can slide down the slope, forming a landslide process. It is necessary to predict the possibility of the occurrence of dangerous natural phenomena when laying automobile dirt roads.

scholarly journals O PAPEL DA JUVENTUDE CAMPONESA NA CONSTRUÇÃO DE ECONOMIAS DE RESISTÊNCIA NO SEMIÁRIDO NORDESTINO/The role of peasant youth in the construction of resistance economies in the northeastern semi-arid region

REVISTA NERA ◽  
2017 ◽  
pp. 144-156
Author(s):  
Gabriel Troilo ◽  
Maria Nalva Rodrigues Araújo
Keyword(s):  
Arid Region ◽  
Semi Arid Region ◽  
Semi Arid

O objetivo do presente trabalho é apresentar as reflexões promovidas pelas organizações sociais do campo e por pesquisadores da questão agrária sobre a forma como as comunidades camponesas do semiárido nordestino se articulam para garantir as condições de produção e subsistência em meio à lógica de livre mercado capitalista, destacando o papel da juventude do campo neste processo. Para tanto foram analisadas as experiências de produção e mercado das comunidades camponesas do semiárido baiano, levando em conta a dinâmica econômica, os enfrentamentos, potencialidades e estratégias de resistência das mesmas frente o avanço do mercado capitalista na atualidade. As ações da juventude do campo na estruturação de economias de resistência, seja pelo associativismo e cooperativismo rural, pela formação de mercados camponeses e ocupação do mercado capitalista tem possibilitado a viabilidade da produção camponesa frente às pressões do modelo de produção agrícola dominante. Tais estratégias tem gerado importantes avanços para o campo no semiárido nordestino, e demonstram os resultados da luta política da juventude do campo pela perpetuação do modo de vida camponês e pela construção da soberania alimentar e territorial das comunidades sertanejas. 

Adsorption of water vapor by soil in semi arid ecosystems: reconciling estimates from Lysimeters and Eddy Covariance

2021 ◽  
Author(s):  
Sinikka Paulus ◽  
Tarek S. El-Madany ◽  
René Orth ◽  
Jacob A. Nelson ◽  
Anke Hildebrandt ◽  
...  
Keyword(s):  
Water Vapor ◽  
Soil Water ◽  
Eddy Covariance ◽  
Water Vapor Adsorption ◽  
Dry Season ◽  
Climate Change Scenarios ◽  
Field Scale ◽  
Vapor Adsorption ◽  
Semi Arid

<p>Current climate change scenarios project altered rainfall frequencies which boosts scientific interest in ecosystems' responses to prolonged dry conditions. Under less rainfall, NRWI may play an increasingly important role, Yet, only sparse data are available to assess the role of non-rainfall water input (NRWI) during times of low water availability across ecoregions. Particularly, soil water vapor adsorption has received little attention at field scale. This term is used for the phase change of water from gas to liquid at highly negative matric potential. Under such conditions, water condensates already at relative humidity < 100%. The process has been broadly studied in laboratories but little is known from field experiments, which rarely cover periods longer than one month. Yet, several studies report soil water uptake from the atmosphere during soil surface cooling and in the early mornings. Lysimeters have played a strong role in quantifying these NRWI. Eddy Covariance (EC) measurements, in contrast, are known for their limited data quality under nighttime conditions when a stable boundary layer hinders the turbulent exchange of mass and energy. Therefore, EC has not been tested yet to trace soil adsorption.<br>    <br>In this contribution we adapt a methodology to derive NRWI from lysimeters data and compare them to EC measurements. We focus mainly on adsorption and evaluate the consistency between adsorption estimated with the lysimeters and negative (downward) latent heat (LE) fluxes from EC. We apply the method to a data set that comprises three years of observations from a semi-arid Spanish tree grass ecosystem. </p><p>Our results show that during the dry season the gradient in water vapour established between the atmosphere (more humid) and the soil pores (more dry) leads to adsorption by the soil. The observations from both instruments suggest that during the dry season, nightly transport of humidity from the atmosphere towards the ground is driven by soil vapor adsorption. This process occurs each night typically in the second half, but begins increasingly earlier in the evening the dryer the conditions are. The amount of water adsorbed is not directly comparable between EC and the lysimeter readings. With the latter, we quantified a yearly mean uptake between 8.8 mm and 25 mm per year. With the lysimeters we measure additionally 23.1 mm of water that condenses as dew and fog in winter, when EC is impeded by stable conditions. We further analyze EC LE measurements from different sites to evaluate if adsorption can be detected from EC data collected at different locations.</p><p>We conclude that the temporal patterns of adsorption estimates from lysimeters match the nighttime negative LE data from the EC technique, although the absolute numbers are uncertain. This might open interesting perspective to fill the knowledge gap of the role of soil water vapor adsorption from the atmosphere at field scale and open the opportunity to broaden the topic across ecosystem research communities. Our results also highlight a potential shortcoming in the interpretation of EC measurements in the case that negative nighttime values, representing physically plausible adsorption, are neglected.</p>

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