Volume application rate adapted to the canopy size in greenhouse tomato crops

Abstract

The application rate of plant-protection products is indicated as a concentration or amount of product per area. Greenhouse crops grow swiftly, and an application rate based on a fi xed amount of product per hectare can result either in large losses and overdoses when the plants are small or to be insuffi cient when the plants are fully developed. To solve these problems, the application rates of plant-protection products need to be adapted to the plant mass present in the greenhouse when the spray is applied. Two models were developed to estimate the leaf area based on easily measured geometric data of the vegetation in a greenhouse tomato crop.The model based on the PRV (Plant Row Volume) had that best results. The calculation of the volume application rate from the PRV has resulted in a reduction of more than 30 % of the quantity of plant protection product sprayed, without decreasing yield. The PRV of a greenhouse tomato (Lycopersicon esculentum Mill.) is an easily measured parameter that enables the estimation of the leaf area index and the use of application strategies adapted to the changes in the plant canopy, saving major amounts of plant protection product used, compared to the conventional system.

Testing the Suitability of a Terrestrial 2D LiDAR Scanner for Canopy Characterization of Greenhouse Tomato Crops

“…They were appropriately stored in sealed plastic bags. Then, under laboratory conditions and before they had dried out, the leaves were removed from the plants and subsamples 80 g in weight were planimetered with a leaf planimeter (LI 3100C, LI-COR, Lincoln, NE, USA) to obtain the total leaf area of the subsample (cm 2 ) as well as the leaf area–weight ratio [ 4 , 33 , 34 ], which enables obtaining the leaf surface area by only weighing the leaves, thus saving time.…”

“…Pesticide residues on vegetables constitute a possible risk to consumers and have been a human health concern [ 3 ]. However, although some researchers have evaluated the optimal volumes of pesticides to be applied [ 4 , 5 ], few studies have related all parameters influencing the relationship between the canopy characteristics and the amount of plant protection product according to the real needs.…”

Thirteen decades of antimicrobial copper compounds applied in agriculture. A review

“…In perennial crops, it is common to use predetermined copper rates and spray volumes, which are indiscriminately applied to orchards of different ages and sizes leading to a waste of resources, such as water, energy, and chemicals and to environmental pollution. However, use of copper on these crops should be based on the volume of the tree canopy or the tree-rowvolume to be treated per hectare (Sutton and Unrath 1984;Sutton and Unrath 1988;Rüegg and Viret 1999;Pergher and Petris 2008;Sanchez-Hermosilla et al 2013;da Silva Scapin et al 2015). For instance, in Brazil, use of tree-row-volumebased copper rates for control of citrus canker has allowed for the copper rates to be downsized to less than one third of former rates without affecting quality of disease control (da Silva Scapin et al 2015;Behlau et al 2017).…”

Spray penetration into asparagus (Asparagus officinalis L.) canopy using different nozzle inclinations and application rates

“…Nevertheless, negative results are known (Zhu et al, 2002). However, some reports in international literature showed that low application rates result in higher pesticide deposits and lower operation costs (Véliz et al, 2010;Sánchez-Hermosilla et al, 2013;Cunha, Victor, & Sales, 2018).…”