Effect of permanent ground cover on agronomic properties and soil fertility in an organic peach orchard

In conventional orchards, weeds on the raw are mainly controlled with chemical herbicides because of their efficiency, their low cost and ease of use. The most common method in organic orchard to eliminate weeds on the raw consists of tillage operations. However, some drawbacks of these mechanical methods have been demonstrated: (1) the energetic cost (non-renewable energy) is high, (2) this method is time-consuming, (3) tillage interferes with the development of superficial roots and can hurt the trunk, (4) the physical, chemical and biological properties of the soil can be disturb and (5) erosion and runoff potentially increase. Cover crops are interesting alternatives to manage ground cover but the effect on the agronomic properties and the soil fertility of these methods should be assessed. This study is included in the national program “Casdar SolAB” supported by the French Ministry of Agriculture. The effect of a White Clover crop versus tillage practice on the tree raw was assessed in an irrigated organic Peach orchard. White Clover was sowed in 2004. Soil parameters (water and nutrients availability, soil porosity, root density, earthworms density, soil profile) and agronomic parameters (yield, fruit quality, pests and diseases damages) were recorded since 2004. A 50% decrease of the organic fertilizer supply in the White Clover treatment has not affected yield and fruit quality from 2005 to 2009. It suggests this cover crop is well adapted to our pedoclimatic conditions without exerting a significant competitive effect. Root density is higher in the superficial layers of the soil in the White Clover treatment. Simplified Beerkan test used to assess soil porosity has also shown that soil porosity is higher in this treatment. No vole damage was observed in the plot

Effect of White clover (Trifolium repens cv. Huia) cover crop on agronomic properties and soil biology in an organic peach orchard

In orchards, cover crops are interesting alternative strategies to tillage or chemical herbicides for managing weeds in the tree row. However, little is known about the effect of cover crops on agronomic properties and soil biology in organic orchards. To fill this gap, the effects of two weed managements, a White clover cover crop (CC) versus classical tillage practice (T) on the tree row, were assessed in an irrigated organic Peach orchard. White clover was sown in 2004, 2006 and 2009 in the tree row and ploughed in 2006 and 2008. Root density, earthworm density, water infiltration rate, nitrogen content and water availability were measured in the soil, in the tree row. In 2009, peach root density observed in the superficial layers was higher in CC treatment. Sampling dates and treatment have a significant effect on total earthworm density with higher abundance observed in CC. However, no difference was observed between CC and T anecic earthworm groups known to make large and vertical burrows. Infiltration rate measured with the simplified Beerkan method was higher in CC treatment. This could be explained by the thick superficial root mat which was associated to a significant higher epigeic earthworm density in CC. Whereas nitrogen supplies were twice lower in CC treatment since 2005, soil nitrogen availability was equivalent in both treatments. These results demonstrate the agronomic interest of nitrogen-fixing plants used as a cover crop in organic peach orchards

Election turnout statistics in many countries: similarities, differences, and a diffusive field model for decision-making

We study in details the turnout rate statistics for 77 elections in 11 different countries. We show that the empirical results established in a previous paper for French elections appear to hold much more generally. We find in particular that the spatial correlation of turnout rates decay logarithmically with distance in all cases. This result is quantitatively reproduced by a decision model that assumes that each voter makes his mind as a result of three influence terms: one totally idiosyncratic component, one city-specific term with short-ranged fluctuations in space, and one long-ranged correlated field which propagates diffusively in space. A detailed analysis reveals several interesting features: for example, different countries have different degrees of local heterogeneities and seem to be characterized by a different propensity for individuals to conform to the cultural norm. We furthermore find clear signs of herding (i.e. strongly correlated decisions at the individual level) in some countries, but not in others.Comment: 15 pages, 9 figures, 7 table

Elucidation of the ATP7B N-Domain Mg2+-ATP Coordination Site and Its Allosteric Regulation

The diagnostic of orphan genetic disease is often a puzzling task as less attention is paid to the elucidation of the pathophysiology of these rare disorders at the molecular level. We present here a multidisciplinary approach using molecular modeling tools and surface plasmonic resonance to study the function of the ATP7B protein, which is impaired in the Wilson disease. Experimentally validated in silico models allow the elucidation in the Nucleotide binding domain (N-domain) of the Mg2+-ATP coordination site and answer to the controversial role of the Mg2+ ion in the nucleotide binding process. The analysis of protein motions revealed a substantial effect on a long flexible loop branched to the N-domain protein core. We demonstrated the capacity of the loop to disrupt the interaction between Mg2+-ATP complex and the N-domain and propose a role for this loop in the allosteric regulation of the nucleotide binding process

Etude de la contribution des parties aeriennes a la reduction du nitrate chez le pecher (Prunus persica L. Batsch)

* INRA, Centre de Recherche d'Avignon, Unite Regionale de Documentation, Montfavet Diffusion du document : INRA, Centre de Recherche d'Avignon, Unite Regionale de Documentation, Montfavet Diplôme : Dr. d'Universit

Response of watersprout growth to fruit load and intensity of dormant pruning in peach tree

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceWatersprout occurrence and growth were investigated over a two-year period in an early maturing peach cultivar (Alexandra) under different intensities of dormant pruning for fruited and defruited trees. A preliminary study focused on identifying the laws that determine the probability of presence and occurrence of watersprouts in relation to watersprout-bearing shoot (WBS) length. The increase in watersprout probability of presence and occurrence resulting from greater WBS length illustrated the high capacity of peach for sprouting. Watersprout lengths were measured, as well as the lengths of young shoots, one-year-old fruit-bearing shoots (FBSs) and older branches considered as WBS in order to evaluate total shoot growth within the tree. Watersprout number and total length tended to be higher under severe dormant pruning and in fruited trees than under light dormant pruning and in defruited trees. This stimulation of watersprout length appeared to compensate for the concomitant lower total length of young shoots, resulting in a constant overall vegetative growth rate for the whole tree. In the second year of the experiment, watersprouts were either removed by summer pruning or not in order to evaluate watersprout incidence on the rest of the tree. After light and severe watersprout removal (WSR), the annual diametrical growth of FBS tended to be higher and lower, respectively, compared to trees not submitted to summer pruning. Light WSR might favour light interception in the centre of the canopy, thus improving assimilate production and allocation to FBS, whereas severe WSR could prevent carbohydrate export from watersprouts to FBS. Under our conditions, the limit at which WSR intensity became detrimental for FBS diametrical growth appeared to be after approximately 75% of the watersprouts were removed. Severe WSR appeared likely to improve fruit diameter, whereas it had no significant impact on the percentage of soluble solid

Root/shoot distribution of NO3- . Assimilation in herbaceous and woody species

International audienc

Root/shoot distribution of NO3- . Assimilation in herbaceous and woody species

International audienc

Participation des racines dans l'assimilation du nitrate chez le pecher

National audienc