Éditeur(s) : Université des Antilles. Service commun de la documentation University of West Indies, Trinidad &Tobago
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : Crop nutrient management is a critical component of productivity and quality. Commercial horticulture has relied almost exclusively on inorganic nutrient sources to satisfy plant nutritional requirements. Compost tea represents a sustainable alternative technology but its use has not been extensively researched. A factorial experiment was conducted subjecting lettuce plants to four increasing concentrations of compost tea; 0, 5, 10 and 20 % (m/v) applied at either 100 or 200 cm3 plant-1 day-1, for 30 days. At the end of the trial, measurements were made of leaf area (LA), yield, shoot and root dry mass (DM), root to shoot ratio, and nitrogen (N) and phosphorus (P) contents of shoots and roots. Compost tea concentration significantly (P < 0.05) affected all growth indices showing a similar pattern. Increasing concentration up to 10 % (m/v), positively improved growth and yield above the control. Increasing further to 20 % (m/v) reduced LA, yield and dry mass. For these variables, applying compost tea at 200 cm3 plant-1 day-1 resulted in a better response. Increasing concentration of compost tea showed a directly proportional relationship to shoot and root N content. However, the effect was non-significant for P. Yield and shoot DM were affected by the combination of compost tea concentration and application rate. Similar patterns of increasing yield were seen for increasing concentration within both rates however, the differences were significant for all concentrations at the higher application rate. Application of 200 cm3, 5 % compost tea resulted in the greatest yield, shoot and root DM. In addition to root DM, root surface area was significantly correlated with yield and shoot DM. Compost tea used at appropriate concentrations improved root growth and lettuce productivity.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16281
V16281

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : 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/256699
Background and Aims Plastic tree-shelters are increasingly used to protect tree seedlings against browsing animals and herbicide drifts. The biomass allocation in young seedlings of deciduous trees is highly disturbed by common plastic tree-shelters, resulting in poor root systems and reduced diameter growth of the trunk. The shelters have been improved by creating chimney-effect ventilation with holes drilled at the bottom, resulting in stimulated trunk diameter growth, but the root deficit has remained unchanged. An experiment was set up to elucidate the mechanisms behind the poor root growth of sheltered Prunus avium trees. Methods Tree seedlings were grown either in natural windy conditions or in tree-shelters. Mechanical wind stimuli were suppressed in ten unsheltered trees by staking. Mechanical stimuli (bending) of the stem were applied in ten sheltered trees using an original mechanical device. Key Results Sheltered trees suffered from poor root growth, but sheltered bent trees largely recovered, showing that mechano-sensing is an important mechanism governing C allocation and the shoot-root balance. The use of a few artificial mechanical stimuli increased the biomass allocation towards the roots, as did natural wind sway. It was demonstrated that there was an acclimation of plants to the imposed strain. Conclusions This study suggests that if mechanical stimuli are used to control plant growth, they should be applied at low frequency in order to be most effective. The impact on the functional equilibrium hypothesis that is used in many tree growth models is discussed. The consequence of the lack of mechanical stimuli should be incorporated in tree growth models when applied to environments protected from the wind (e.g. greenhouses, dense forests).
ISSN: 0305-7364

hal-01032056
https://hal.archives-ouvertes.fr/hal-01032056
DOI : 10.1093/aob/mcn054