Open vase canopy architecture is common in low density pear orchards of the Pacific Northwest region of the United States. This system is used to manage vigorous varieties in the absence of dwarfing rootstocks ( Neri et al., 2008 ; Zhang et al
Abstract
A technique for characterizing apple (Malus domestica Borkh.) tree canopies using fisheye (hemispherical) photography is described. The technique has the advantages of speed of sampling and analysis, and of providing permanent records of canopy structure. Photographs were taken inside the canopy, and the percentage sky visible determined by densitometry. The percentage sky in the photographs was correlated to the light climate at the site of the photograph.
To evaluate effects of canopy and micro-irrigation under trees on accumulation and leaching of phosphorus (P) and heavy metals in agricultural sand soils, the horizontal and vertical variations of soil P and metals in a 408-m2 plot within a grove under grapefruit (Citrus paradisi Macf.) production near Fort Pierce, Fla., was examined. A high horizontal variation of labile soil P and metal concentrations was observed. Across the row, the highest values of pH, EC, water-soluble P, and all metals occurred in the soils under the canopies, and the lowest values occurred in the soils near the water furrow or the midway of the inter-row. Along the grapefruit row, the highest values of many measured variables occurred along the northern side of the citrus tree and close to the emitter. The downward movement of P, Cu, and Zn in the soils was more significant in the soils in open areas (near the water furrow and midway of inter-neighboring trees) than those under the canopies. The differences in labile P and metal spatial distributions in the soils were related to the location of emitter fertigation and differences in rainfall-induced leaching in the field. The results suggest that applying fertilizers to sites under the canopy rather than the spaces between the trees can minimize leaching losses of nutrients.
into the canopy, adjusts leaf:fruit and shoot:root ratios ( Rana et al., 2011 ; Ryugo, 1986 ), improves harvest efficiency, and reduces limb breakage ( Austin, 1997 ; Clark and Matheny, 2010 ; Hrotkó, 2013 ). Lack of pruning, however, results in
of one side of each leaf and the ground area the tree occupies ( Bréda, 2003 ). LAI is an important physiological parameter within an orchard because it is easily manipulated with training and pruning, and can significantly affect canopy microclimates
studied and tend to be difficult to generalize as a result of wide variations in varieties, planting densities, and cultural practices. Growth stage and crop size is especially important for horticultural crops because canopy light interception is a
and clusters become wetted by condensation or precipitation. Canopy management practices that reduce humidity and promote cluster dryness help minimize the incidence of both types of rots ( Bettiga and Gubler, 2013 ). Exposure to precipitation may be
spaced and there is potential for plant canopies to influence the proportion of sprinkler irrigation water that is captured relative to that which falls unintercepted between containers. We use the term CF to describe sprinkler irrigation capture: where
, and it is not known to what degree night interruption might affect the net canopy carbon gain and subsequent plant growth. Extending the length of the day to obtain a certain light integral might result in greater net photosynthesis as a result of a
providing a simple and effective basis for characterizing salinity stress response among turfgrass cultivars. Non-destructive, RS canopy reflectance in the near-infrared (980 nm) has been reported by Thenkabail et al. (2000) as sensitive to leaf water