Improvement of spray application process in greenhouse tomato crop : assessment of adapted spraying technologies and methods for canopy characterization
Vegetable production in greenhouses is an important and productive economic activity for agricultural businesses in Southern Europe. One of the most risky factors affecting this activity is the use of plant protection products (PPP). Several studies have demonstrated that the use of vertical boom sp...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/458447 |
| Acceso en línea: | http://hdl.handle.net/10803/458447 https://dx.doi.org/10.5821/dissertation-2117-112423 |
| Access Level: | acceso abierto |
| Palabra clave: | Àrees temàtiques de la UPC::Enginyeria agroalimentària 631 |
| Sumario: | Vegetable production in greenhouses is an important and productive economic activity for agricultural businesses in Southern Europe. One of the most risky factors affecting this activity is the use of plant protection products (PPP). Several studies have demonstrated that the use of vertical boom sprayers in greenhouses has several advantages over that of traditional spray guns, such as improved spray distribution, reduced labour costs, and reduced operator exposure. On the other hand, canopy characterization is important for a better adjustment of the amount of pesticide/mixture sprayed, and is a key factor in spray process improvement enabling a significant reduction in the quantity of PPP used, which increases the efficiency of the process. The main objective of this doctoral thesis is to improve the efficiency of the pesticide application process for greenhouse crops by two actions were planned: a) adding an air assistance device to a manually pulled trolley with vertical booms, b) developing a method for canopy characterization. The effect of the addition of the air assistance on a modified hand-held pulled trolley sprayer was evaluated using two different crop fields (tomato with high and low canopy density) and several sprayer types (nozzle type, air assistance, and spray volume). Deposition on the canopy, deposition coverage, and deposition distribution uniformity have been assessed. No significant differences on deposition were obtained with the reference system applying high volume rate compared to modified trolley with air assistance and low volume rate. In general air assistance and flat fan nozzles reduce volume rates while maintaining or improving spray quality distribution. Furthermore, the influence of air-assistance characteristics on spray application was evaluated. For this reason, field tests were arranged for three different sprayers: 1) a modified hand-held trolley sprayer with air assistance high and low velocity; 2) a self-propelled sprayer specifically designed for greenhouse pesticide applications; 3) an autonomous self-propelled sprayer commanded by remote control. Each sprayer was assessed by liquid and air vertical distribution. The evaluation was done considering normalised canopy deposition and liquid losses to the ground. The results indicated that increasing the air velocity does not increase the efficiency of the spray application. In general, the modified hand-held trolley sprayer showed the best results in terms of deposition and uniformity of distribution. These results were confirmed through an evaluation of air uniformity and liquid distribution. The characterization of the canopy was carried out in three different commercial tomato greenhouses, all of which contained crops planted in a twin-row system. Electronic characterization was performed using a LiDAR sensor (LMS-200, SICK) with an 180° angle measurement by scanning a pair of plants from both sides. The main parameters obtained were canopy height, width, and volume, and leaf area. From these parameters, other important parameters were as tree row volume, leaf wall area, leaf area index. A general overview of the results showed an overestimation of the parameters measured manually because of the high definition of the profile obtained with this sensor. An estimation of the canopy volume with the electronic device was shown to be a reliable method for estimating the canopy height, volume, and density. With this sensor was possible to assess the high variability of the canopy density along a row. The determination of the amount of PPP necessary for adequate control of pests and diseases should be adjusted according to the characteristics of the subject canopy. Advancements in spraying techniques that enable fast and robust characterization of major canopy parameters, and advancements in efficient spray distribution technology are essential for improved pesticide spray applications. |
|---|