Search results for " SOIL"

Slope threshold for overland flow resistance on sandy soils

2021

Recent research on rill flows recognised that an 18% slope can be used to distinguish between ‘gentle’ and ‘steep’ slope cases for the detected differences in hydraulic (flow depth and velocity) and sediment transport variables (flow transport capacity, actual sediment load). The effects of slope on flow velocity, friction factor and transport capacity and their interactions affect process-based erosion modelling. The main aim of this paper is to investigate, for the first time, how slope affects the overland flow resistance on sandy soils, which are characterised by loose particles readily available to be transported and deposited. Using literature measurements carried out in sandy soils f…

Flow resistance in mobile bed rills shaped in soils with different texture

2021

Rill erosion is considered one of the most important soil processes because of the large amount of soil loss due to the development of a rill network able to promote an efficient transport of both rill flow-detached particles and those delivered from the inter-rill areas. Rill flow experiments are useful to overcome the gap in rill hydraulics knowledge and to test the reliability of currently applied uniform open channel flow equations for mobile bed rills. In this paper the applicability of a theoretical flow resistance equation, based on a power-velocity profile, to rill channels shaped on soils having different textures was investigated. The measurements (437 runs) of water depth, cross-…

Rainfall timing and runoff: The influence of the criterion for rain event separation

2016

Abstract Rain is not uniform in time and space in semiarid areas and its distribution is very important for the runoff process. Hydrological studies usually divide rainfall into events. However, defining rain events is complicated, and rain characteristics vary depending on how the events are delimited. Choosing a minimum inter-event time (MIT) is a commonly used criterion. Our hypothesis is that there will be an optimal MIT that explains the maximum part of the variance of the runoff, with time to runoff used as a surrogate. The objective is to establish a procedure in order to decide upon this optimal MIT. We developed regressions between time to runoff (T0) and three descriptive variable…

Using the ARP-03 for high-resolution mapping of calcic horizons

2013

A b s t r a c t. The aim of this work is to present a fast and cheap method for high-resolution mapping of calcic horizons in vineyards based on geoelectrical proximal sensing. The study area, 45 ha located in southern Sicily (Italy), was characterized by an old, partially dismantled marine terrace and soils with a calcic horizon at different depths. The geoelectrical investigation consisted of a survey of the soil electrical resistivity recorded with the Automatic Resistivity Profiling-03 sensor. The electrical resistivity values at three pseudo-depths, 0-50, 0-100 and 0-170 cm, were spatialized by means of ordinary kriging. A principal component analysis of the three electrical resistivit…

Biohydrology research after Landau 2013 conference

2014

Biohydrology gives a new view on hydrological research. The impact of biota on hydrological processes was a disregarded topic in the early years of hydrology research. It has been present since the 1960s, but as a „Cinderella“ research topic. It emerged as a new aspect of the hydrological processes after the 1980s. In the 21st century, it has become a well established research topic, bringing new knowledge to aid understanding on how biota influence the hydrological cycle and the rates of hydrological processes. The importance of biohydrology research is growing, and the number of conferences, publications and research projects is being doubled every decade. The 4th Biohydrology conference,…

Effects of Soil Solarization With Different Plastic Films and Fumigation With Combination of 1,3-Dichloropropene and Chloropicrin on Strawberry Prote…

2012

FUNCTIONAL NONRETENTIVE FECAL SOILING AND STRESSFUL LIFE EVENTS

2019

Introduction: Functional non-retentive fecal soiling (FNRFS), or encopresis without constipation, is a common problem in pediatric age. FNRFS is associated with high levels of distress for both children and parents and with emotional disorders in about 30%-50% of affected children. This study aimed to evaluate stressors on a sample of children with FNRFS comparing to a group of typical devolpment children (TDC). Methods:154 subjects participated in the study: 56 FNRFS children (37 males; mean age 10.87 years ± 1.68); 98 TDC (65 males; mean age 11.3 years ± 1.85). All participants were evaluated for the presence of stressful events (LCU) using the Coddington Life Events Scales (CLES). Result…

First morphological and molecular investigation of the mycobiota associated with Astragalus nebrodensis in its natural environment (Madonie mountains…

2023

Although Astragalus nebrodensis plays a fundamental ecological role, mycorrhizal fungi associated with this species have never been investigated in natural habitats. Our aim was to check the presence and occurrence of Arbuscular Mycorrhizal Fungi (AMF) in roots of A. nebrodensis in a natural habitat and to screen the fungal diversity in the surrounding soil, considering the positive influence of mycotrophic shrub species on soil microbiota. A morphological analysis was performed on A. nebrodensis roots samples from the Madonie mountains (Sicily, Italy), while high-throughput-sequencing was carried out in A. nebrodensis roots and in the associated soil. Observations of A. nebrodensis roots r…

Diffuse soil gas emissions of gaseous elemental mercury (GEM) from hydrothermal-volcanic systems: An innovative approach by using the static closed-c…

2016

This study was aimed to test a new methodological approach to carry out measurements of gaseous elemental mercury (GEM) diffusively emitted from soils in hydrothermal-volcanic environments. This method was based on the use of a static closed-chamber (SCC) in combination with a Lumex® RA-915M analyzer that provides GEM measurements in a wide range of concentrations (from 2 to 50,000 ng m-3). Gas samples were collected at fixed time intervals from the SCC positioned on the ground (time-series samples). The Lumex® inlet port was equipped with a three-way Teflon valve allowing the free entrance of air through a carbon trap, in order to: (i) prevent disturbance to the Lumex® operative flow rate …

The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion.

2013

Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, …