Critical irrigation threshold and cranberry yield components
Yield components are useful for characterizing the impact of crop management parameters on cranberry yield and are known to be influenced by irrigation management. This study was conducted to evaluate the potential contribution of cranberry yield components to maximizing yield, and the influence of the soil water tension threshold used to initiate irrigation (SWTI) on those components. During the 2011 and 2012 growing seasons, tensiometers were installed at three production sites in Quebec to test SWTI values ranging from 5.5 to 10.0kPa. Sites were cropped to cranberries to evaluate the impact of these irrigation treatments on yield components. The four most important cranberry yield components related to final yields were, in order of importance, the number of marketable berries per quadrat (BM/Q), the number of uprights per quadrat (U/Q), the number of marketable berries per upright (BM/U), and the marketable fruit set (BM/F). Significant reductions in BM/Q, BM/U and BM/F were observed when SWTI varied from 8.5 to 10.0kPa while a reduction in U/Q was associated with a SWTI of 5.5kPa. A SWTI ranging from 7.0 to 8.0kPa significantly improved the principal yield components.
Evidence of drought-sensitive periods from flowering to maturity on highbush blueberry
The effects of water deficit on highbush blueberry (Vaccinium corymbosum L.) have been little studied. This study, conducted on container-planted shrubs, aimed at determining the influence of water stress on growth, water relations and fruit production of the plant during two consecutive years. Drought periods of approximately 3 weeks, as monitored from the transpiration of control plants, were applied at various phenological stages of plant development, from blossoming to harvest, so as to evaluate their direct effects. Highbush blueberry reacted very quickly to drought by reducing transpiration and stopping stem diameter growth and shoot elongation. Its ability to recover depended on the stress level and the drought implementation dynamics. Under moderate stress (35% less transpiration than a well-watered shrub) the recovery potential was almost complete. In all cases water stress during fruit growth and ripening strongly influenced yield by reducing the mean fruit weight and size. Drought after-effects, as assessed from one season to the other, were small, except when stress occurred during flower induction. In that case the number of flowers was reduced in the following year as well as the number of fruits, although fruit size was greater resulting in only a slight reduction in yield. In all cases, photosynthetic performance during the following year appeared not to alter, but water stress imposed to obtain large fruit cannot replace pruning without jeopardising the shrub architecture.
Detection of Fractures Based on Directional Filtering in Image Logging
According to the feature of the direction of fractures in image logging, a method of fracture detection in image logging based on directional filtering is presented in this paper. The fracture image is filtered by the corresponding filter based on the local direction of fractures, which enhances the fracture traces in the direction of fractures in image logging. The final fracture traces are extracted by the combination of the results of both directional filtering and the threshold segmentation. Experimental results show this method effectively detect the fractures in image logging.