Search results for " Fisheries"

Humusica 1, article 1: Essential bases – Vocabulary

2018

International audience; The Special Issue Humusica 1 corresponds to a field guide for the classification of terrestrial humus systems and forms. The present first article of the issue defines vocabulary, objects and concepts necessary for: (a) field investigation, (b) understanding the process of classification, (c) assigning ecological significance to the defined morpho-functional units, (d) discussing and exchanging scientific data about humus systems. The article starts with general considerations, as the necessity humans have to classify natural objects for sharing ideas and information on them. Then the article focuses on soil as functional element of every ecosystem. Historical and re…

Pedotransfer functions for estimating soil water retention curve of Sicilian soils

2019

Pedotransfer functions (PTFs) make use of routinely surveyed soil data to estimate soil properties but their application to soils different from those used for their development can yield inaccurate estimates. This investigation aimed at evaluating the water retention prediction accuracy of eight existing PTFs using a database of 217 Sicilian soils exploring 11 USDA textural classes. PTFs performance was assessed by root mean square differences (RMSD) and average differences (AD) between estimated and measured data. Extended Nonlinear Regression (ENR) technique was adopted to recalibrate or develop four new PTFs and Wind’s evaporation method was applied to validate the effectiveness of the …

Comparing yield and growth characteristics of four pastoral plant species under two salinity soil levels

2018

Influence des phosphates naturels et des mycorhizes à vésicules et à arbuscules sur la croissance et la nutrition minérale de Zizyphus mauritiana Lam…

1998

Rock phosphate and vesicular-arbuscular mycorrhiza effects on growth and mineral nutrition of Zizyphus mauritiana Lam. in an alkaline soil. The influence of vesicular-arbuscular mycorrhizae (VAM) and rock phosphate (RP) was studied on jujube (Zizyphus mauritiana Lam.), a multipurpose fruit tree in Sahelian agroforestry systems. Jujubes were inoculated or not by Clomus manihotis Howeler, Sieverding & Schenck in an alkaline sandy soil to which were added five levels of RP (12 % of P) : 0.00, 0.31, 0.62, 1.25 et 2.50 g P/kg of soil, equivalent to 0, 775, 1 550, 3 125 et 6 250 kg P ha -1 . The jujubes seedlings grew poorly without mycorrhizal colonization and without RP applications (figures 1a…

Ecophysiological Modeling of Grapevine Water Stress in Burgundy Terroirs by a Machine-Learning Approach

2016

13 pages; International audience; In a climate change scenario, successful modeling of the relationships between plant-soil-meteorology is crucial for a sustainable agricultural production, especially for perennial crops. Grapevines (Vitis vinifera L. cv Chardonnay) located in eight experimental plots (Burgundy, France) along a hillslope were monitored weekly for 3 years for leaf water potentials, both at predawn (Ψpd) and at midday (Ψstem). The water stress experienced by grapevine was modeled as a function of meteorological data (minimum and maximum temperature, rainfall) and soil characteristics (soil texture, gravel content, slope) by a gradient boosting machine. Model performance was a…

GenExP, un logiciel simulateur de paysages agricoles pour l'étude de la diffusion de transgènes

2007

 ; The software GENEXP allows to simulate 2-dimensional agricultural landscapes by using a traditional algorithmic geometry. Based on real or realistic field-patterns, GENEXP provides multiannual maps of agricultural landscapes, which are used by softwares simulating the dispersal of GM pollen grains and seeds at various scales.; GENEXP est un simulateur de paysages agricoles qui engendre des découpages parcellaires en utilisant une géométrie algorithmique classique. GENEXP fournit, sur la base de parcellaires réels ou réalistes, des cartes pluriannuelles de paysages agricoles utilisables par des logiciels qui simulent la dispersion des pollens et des graines d'OGM à différentes échelles.

Effects of mowing on fungal endophytes and arbuscular mycorrhizal fungi in subalpine grasslands

2013

International audience; In French subalpine grasslands, cessation of mowing promotes dominance of Festuca paniculata, which alters plant diversity and ecosystem functioning. One of the mechanisms underpinning such effects may be linked to simultaneous changes in the abundance of fungal symbionts such as endophytes and arbuscular mycorrhizal fungi. In field conditions, mowing reduced the abundance of the endophyte Neotyphodium sp. in leaves of F. paniculata by a factor of 6, and increased mycorrhizal densities by a factor of 15 in the soil. In greenhouse experiments, the mycorrhizal colonization of Trifolium pratense and Allium porrum increased 3- fold and 3.8- fold respectively in mown vs u…

Raspberry breeding and biotisation for increasing plant stress tolerance and antioxidant activity

2008

International audience; Chemical inputs used in red fruit production can be detrimental to the environment and pesticides are not always efficient in controlling plant diseases. In addition, it is suspected that conventional agricultural practices have a negative impact on antioxidant activities in red fruits. Therefore new cultural approaches are required in order to produce red fruits of high quality. This involves an integrated programme of plant breeding and development of sustainable agricultural practices. Antioxidant activity was compared in leaves and berries of six raspberry cultivars for the selection of varieties for a breeding programme. This showed that cultivars that had the h…

Influence of nitrogen availability on seed nitrogen accumulation in pea

1999

International audience; The final seed nitrogen concentration (the ratio of seed N and dry matter content) is highly variable in pea (Pisum sativum L.) and N remobilization during seed filling may limit yield by restricting the seed filling period. This study was conducted to determine how seed N accumulation is regulated in pea. The effect of N availability and distribution on individual seed N accumulation rate at different nodes was investigated in three genotypes grown in the field and glasshouse under various levels of N fertilizer, depodding, and defoliation. The N content of vegetative plants parts (stems, leaves, podwalls) and seeds from three mainstem nodes were regularly recorded.…

The mycorrhizal soil infectivity and arbuscular mycorrhizal fungal spore communities in soils of different aged fallows in Senegal

2001

This work was carried out to determine the influence of the duration of fallow and of physico-chemical components of soils on the distribution of endomycorrhizal fungal spores and the mycorrhizal soil infectivity. The mycorrhization of indigenous plants from the fallows was examined and it was concluded that, except for Cassia obtusifolia, fungal colonization was poorly developed. No correlation was established between spore populations and duration of fallow or between grazed and fenced areas. The relationships between abundance of mycorrhizal spores and the physico-chemical characteristics of the soils were markedly variable among species of mycorrhizal fungi. The results did not provide …