Search results for "Forestry"
showing 10 items of 1998 documents
Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest
2012
Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …
Compensation of Oxygen Transmittance Effects for Proximal Sensing Retrieval of Canopy–Leaving Sun–Induced Chlorophyll Fluorescence
2018
Estimates of Sun–Induced vegetation chlorophyll Fluorescence (SIF) using remote sensing techniques are commonly determined by exploiting solar and/or telluric absorption features. When SIF is retrieved in the strong oxygen (O 2 ) absorption features, atmospheric effects must always be compensated. Whereas correction of atmospheric effects is a standard airborne or satellite data processing step, there is no consensus regarding whether it is required for SIF proximal–sensing measurements nor what is the best strategy to be followed. Thus, by using simulated data, this work provides a comprehensive analysis about how atmospheric effects impact SIF estimations on proximal sensing, regarding: (…
New national and regional Annex I Habitat records: from #45 to #59
2022
New Italian data on the distribution of Annex I Habitats are reported in this contribution. Specifically, 8 new occurrences in Natura 2000 sites are presented and 27 new cells are added in the EEA 10 km × 10 km reference grid. The new data refer to the Italian administrative regions of Apulia, Campania, Calabria, Lazio, Tuscany, Umbria, Sardinia, and Sicily.
Sentinel-1 & Sentinel-2 Data for Soil Tillage Change Detection
2018
In this paper, an algorithm using Sentinel-1 (S-1) and Sentinel-2 (S-2) data to identify changes of tillage over agricultural fields at approximately similar to 100m resolution is presented. The methodology implements a multiscale temporal change detection on S-1 VH backscatter in order to single out VH changes due to agricultural practices only. The algorithm can be applied over bare or scarcely vegetated agricultural fields, which are identified from S-2 NDVI measurements. An initial assessment at farm scale using in situ and S-1 and SPOT5-Take5 data, acquired over the Apulian Tavoliere in southern Italy in 2015, is illustrated. A full validation of the approach is in progress over three …
The effect of substituted urea herbicides on the growth of excised tomato roots
1983
Summary The action of 23 herbictdal substituted ureas on the growth of excised tomato roots was studied in order to determine whether there is a link between the effects of these herbicides on oxidative phosphorylation and on the growth of non-photosynthetic tissues. Fourteen of these herbicides were inhibitory; chlortoluron and TBU were stimulatory but only in the light. Substituted ureas known to affect plant mitochondria inhibited root growth but to a lesser extent than some which had no action on mitochondria. No clear relationship was found between actions on mitochondria and on root growth. It is suggested that targets other than photosynthesis and oxidative phosphorylation exist for …
Behaviour of the herbicide EL-107 in wheat and rape grown under controlled conditions
1987
Summary The behaviour of 14C-EL-107 has been evaluated in winter wheat and rape, which are tolerant and susceptible, respectively, under field conditions. After 10- to 13-days’growth under controlled conditions, seedlings were allowed to absorb the herbicide through the roots. Two experiments were conducted to study the absorption and the metabolism of EL-107. Absorption was estimated during a 5-day treatment at the rate of 1–47 μM, and metabolism was studied after a 1-day treatment at 14.7 μM. The results showed that (i) rape plants absorbed more herbicide than wheat, and translocated less radioactivity into their shoots, and (ii) the metabolism of EL-107 proceeded actively only in the sho…
Influence of resource quality on the composition of soil decomposer community in fragmented and continuous habitat
2004
Abstract The aim of this field experiment was to explore the combined effects of two factors potentially affecting the local composition of soil decomposer community: resource quality and habitat fragmentation. We created humus (habitat) patches with three different resource quality: (1) pure homogenised humus; (2) humus enriched with needle litter; and (3) humus enriched with needle and leaf litter. These patches were embedded either in a mineral soil matrix, thus representing fragmented habitat, or in natural forest soil, representing continuous (non-fragmented) habitat. The development of faunal (colonisations/extinctions of soil animal populations) and microbial communities in the patch…
Soil processes are not influenced by the functional complexity of soil decomposer food webs under disturbance
2002
Abstract A 3 yr experiment, using field lysimeters with seedlings of Scots pine (Pinus sylvestris) growing in raw humus, was established to study how functional complexity of the soil decomposer food web affects ecosystem functioning. The functional complexity of decomposer system was manipulated by (1) allowing either microfauna (fine mesh) or microfauna+mesofauna (coarse mesh) to enter the initially defaunated systems, and (2) treating half of the lysimeters with wood ash. To test whether altering functional complexity of the decomposer community is related to the system's ability to resist disturbance, the lysimeters were later on disturbed with drought. Ecosystem function, measured as l…
Seasonal evolution of the quality of fresh glasshouse tomatoes under Mediterranean conditions, as affected by air vapour pressure deficit and plant f…
2000
Abstract Changes in yield and quality of fresh tomatoes in response to air vapour pressure deficit (VPD) and plant fruit load were studied under Mediterranean summer conditions. Plants thinned to three or six fruits per truss were grown in two compartments, one at a VPD below 1.5 kPa, the other without VPD control. The seasonal trend in fruit yield and quality was assessed from April to September by weekly measurement of number, fresh weight and dry matter content of harvested fruits, together with the occurrence of blossom-end-rot (BER) and cracking. On two occasions, in July and September, sugar and acid content was measured at three ripening stages. The seasonal decrease in fresh yield w…
Transition vers des systèmes agricole et agroalimentaire durables : quelle place et qualification pour les légumineuses à graines ?
2017
Cet article propose une analyse historique du processus de verrouillage du système agroalimentaire en défaveur des légumineuses à graines, à l’aune des théories évolutionnistes. Plusieurs mécanismes d’autorenforcement permettent de comprendre pourquoi ces espèces sont de moins en moins cultivées en France face à un système agro-industriel qui s’est spécialisé en faveur des céréales, favorisant à l’amont l’usage d’engrais azotés de synthèse et limitant à l’aval les investissements pour les légumineuses en alimentation humaine. Cet article s’interroge alors sur les perspectives de déverrouillage.