Search results for " Spatial variability"

Feeding ecology of the sand smelt, Atherina boyeri (Risso, 1810) (Osteichthyes, Atherinidae), in the western Mediterranean: evidence for spatial vari…

2005

The feeding ecology of the sand smelt Atherina boyeri Risso 1810 (Osteichthyes, Atherinidae) was investigated in a Mediterranean coastal basin (Stagnone di Marsala, Italy) by means of carbon and nitrogen stable isotope ratios. Sampling was carried out seasonally in 1999 in two locations characterised by different depth and vegetal coverage. Throughout the year the sand smelt showed enriched δ 13C and δ 15N values in both sampling locations (δ 13C about −12‰ and δ 15N about 12‰). This result suggests the overall importance of the benthic pathway in the food web leading to A. boyeri. Our isotopic picture is only in partial agreement with stomach content data from the literature. Stomach conte…

Dati preliminari sulla variabilità spazio-temporale di Paracentrotus lividus nell’ AMP “Capo Gallo Isola delle Femmine”

2009

A system for the real-time geo-referenced measurement of soil parameters

2011

The aim of this research is to develop a system for accurately measuring in real-time, collecting and processing a high amount of geo-referenced data of soil physical-mechanical parameters, e.g. cone penetrometer resistance, index of soil compaction, and draft force. The system for measuring the soil cone penetrometer resistance is comprised of a load cell, connected to a rod, ending with a cone, and is mounted on a frame, fixed to the front part of a tractor. The system for measuring the draft force required to till the soil is comprised of a load cell, mounted on the hitch hook of a tool carrier, towed by the tractor. Moreover, in order to test the usefulness of the system with different …

Fundamentals of Precision Agriculture

2023

Precision agriculture or precision farming is the targeted application of crop input according to the locally determined crop needs. Therefore, it is the geo-referenced application of crop inputs, whose rates should be those required by the crop. The most essential points of information about the topic being described are: overview; brief history of precision agriculture; theoretical basics of precision agriculture; precision agriculture cycle; geo-referenced measurement of within-field parameters; analysis and interpretation of geo-referenced data for mapping within-field parameters; spatially variable rate application of crop inputs; instruments for precision agriculture; current scenario…

Precision Agriculture: Past, Present and Future

2011

From 1978 the Global Positioning System, needed for sensing the position of military targets (e.g. buildings, machinery), was developed as a pure military system, while in 1983 it was made available also for public use. Therefore, at the beginning of 80s precision agriculture, requiring GPS for sensing the position to which any measured field parameter must be geo-referenced, was implemented for the first time in US. In fact, soil and crop parameters are spatially variable in a field, so that spatially uniform rate crop input applications cause increased environmental impact and crop input waste. In order to reduce the environmental impact and optimise the use of crop inputs, precision agri…

Blowing in the wind: how many roads can a phytoplanktont walk down? A synthesis on phytoplankton biogeography and spatial processes

2015

The selected theme of the 17th Workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), ‘‘Biogeography and Spatial Patterns of Biodiversity of Freshwater Phytoplankton,’’ offered the opportunity to explore one neglected aspect of phytoplankton ecology: the distribution of species in the geographic space. This paper summarizes the outcomes of 20 selected contributions among those presented at the workshop. The articles report the results from studies carried out in five continents (only Oceania is not represented) and on a wide array of aquatic ecosystems (deep and shallow natural lakes, man-made lakes, temporary and permanent ponds, rivers). The topics analyze…

Spatial microbial community structure and biodiversity analysis in "extreme" hypersaline soils of a semiarid Mediterranean area

2015

In recent years specific attention has been paid on the biotechnological potential of microorganisms in extreme soils, in particular in saline soils. Salinity is one of the most widespread soil degradation processes on the Earth, and saline soils can be defined as extreme soils or border line habitats in which several factors, as high salt content, may limit the growth of organisms. In this study, the physical, chemical and microbiological soil properties were investigated in the shallower horizon of natural saltaffected soils in Sicily (Italy). The main aim of the research was to evaluate the structure and diversity of bacterial and archaeal communities by terminal-restriction fragment len…

Spatial variability of stable carbon and nitrogen isotope ratios in a Mediterranean coastal lagoon

2005

Exploring the trophic pathway of organic matter within the Mauguio lagoon (southern France, western Mediterranean), we found spatial differences in the isotopic composition (both δ13C and δ15N values) of organic matter sources (primary producers, particulate and sedimentary organic matter), which were mirrored in the upper trophic levels (invertebrates and fish). On average, δ13C was heavier by about 1.5–2‰ in the location under marine influence than in the sites influenced by freshwater discharge. The opposite trend was found for δ15N, which attained maximum values in the north-central zone influenced by freshwater delivery. For both C and N stable isotope ratios, the highest spatial varia…

Fine-scale spatial variability of soil organic carbon and related environmental variables in a protected area of Sicily, Italy

2008

The institution of Natural Reserves has promoted, in Italy, the conservation and the environmental improvement of several areas and their physical and biological factors. Agriculture, forestry and every human activity are regulated to preserve their high ecological and naturalistic value. Land use, in particular, must follow careful rules to preserve the soil fertility and to limit the factors of landscape degradation. Maps of soil organic carbon (SOC) or soil organic matter (SOM) are of interest for agricultural management, resulting a very important soil fertility parameter, as well as in environmental policy related to the terrestrial sequestration of atmospheric carbon. Thus, a better u…

Stable isotopes and trophic positions of littoral fishes from a Mediterranean Marine Protected Area

2008

Stable isotope analyses were employed to explore feeding and foraging habitats and trophic levels of littoral fishes in a western Mediterranean Marine Protected Area (Egadi Islands, Sicily, Italy). Carbon and nitrogen stable isotope ratios were measured in primary producers, invertebrates and fishes collected in December 2001 and January 2002. Fishes of the littoral region of the Egadi Islands had isotopic signatures that fell into a wider range for δ13C (about 6‰) than for δ15N (about 3‰). Carbon isotope ratios were consistent with a food web based on mixed sources and two trophic pathways leading to different fish species. Differences in the isotopic composition between islands were highe…