This study explores the use of structure from motion (SfM), a computer vision technique, to model vine canopy structure at a study vineyard in the Texas Hill Country. Using an unmanned aerial vehicle (UAV) and a digital camera, 201 aerial images (nadir and oblique) were collected and used to create a SfM point cloud. All points were classified as ground or non-ground points. Non-ground points, ...

BACKGROUND Soil application of systemic neonicotinoid insecticides can provide opportunities for long-term control of insect pests in vineyards, with minimal risk of pesticide drift or worker exposure. This study compared the effectiveness of neonicotinoid insecticides applied via irrigation injection on key early-season and mid-season insect pests of vineyards in the eastern United States. R...

Grapevine irrigation is becoming an important practice to guarantee wine quality or even plant survival in regions affected by seasonal drought. Nevertheless, irrigation has to be controlled to optimise source to sink balance and avoid excessive vigour. The results we present here in two grapevine varieties (Moscatel and Castelão) during 3 years, indicate that we can decrease the amount of wate...

Stomatal responsiveness to evaporative demand (air vapour pressure deficit (VPD)) ranges widely between species and cultivars, and mechanisms for stomatal control in response to VPD remain obscure. The interaction of irrigation and soil moisture with VPD on stomatal conductance is particularly difficult to predict, but nevertheless is critical to instantaneous transpiration and vulnerability to...

The impacts of three different water stresstiming patterns for three levels of seasonal applied water on production were evaluated in mature almond trees [Prunus dulcis (Mill.) Webb cv. Nonpareil] grown under high-evaporative demand conditions in the southern San Joaquin Valley of California. The stress timing patterns involved biasing water deficits to the pre-harvest or postharvest periods in...

Any multivariate density can be decomposed through successive conditionings into basic building blocks involving only pairs of variables. The various ways in which this can be done are called regular vines; C-vines and D-vines are prime examples of such structures. A pair-copula construction (PCC) is a modelling strategy in which conditional and unconditional bivariate copula densities are assi...

Th e infl uence of partial defoliation performed at diff erent grapevine growth stages on yield components, vegetative growth and fruit composition of ‘Istrian Malvasia’ (‘Malvazija istarska’) vines was investigated. During two consecutive seasons partial defoliation was performed manually at three grapevine growth stages; before bloom (BB), aft er bloom (AB), and at the beginning of bunch clos...

We only have a limited understanding of the nutrient uptake physiology of individual roots as they age. Despite this shortcoming, the importance of nutrient uptake processes to our understanding of plant nutrition and nutrient cycling cannot be underestimated. In this study, we used a N depletion method that allowed for the measurement of nitrate-N uptake rates on intact, individual, fine roots...