Plot size, sample sufficiency, and number of repetitions are factors that affect the experimental errors or residuals and the expression of true differences among treatments. The objective of this study was to determine, using statistical models, the appropriate sample size for application technology experiments in coffee crops through the evaluation of foliar spray deposition and soil runoff in the ground-based application of pesticides. In the first stage, we determined the quantity of leaves per set and the volume of the solution for washing the leaves and extracting the tracer. We analyzed the variability between the coefficients of variation (CVs) of the amount of tracer extracted in two droplet classes (fine and coarse), for the different parts of the plants, and for the different quantities of leaves per set that were organized into intervals of five leaves (1–5, 6–10, 11–15, and 16–20). Less variability was found in the intervals with 10 leaves per set and using 100 mL of extraction solution. In the second stage, a field experiment was conducted using an entirely randomized design with 20 plots: 10 sprayed with fine droplets and 10 with coarse droplets. In each plot, 10 sets (samples) with 10 leaves each were collected from the upper and lower canopy of the coffee trees. Moreover, 10 Petri dishes were placed per plot and collected after application. Based on the results of the spray deposition (mass of tracer extracted per cm2 of leaf), we determined the optimal sample size using the maximum curvature and maximum curvature of the coefficient of variation methods. Higher variabilities were related to the targets that are more difficult to reach. Thus, this study determined an optimal sample size between five and eight sets of leaves for spray deposition, and four to five Petri dishes for soil runoff.
Including the correct combination of factors for the application technology of pesticides can improve their distribution on their targets. The aim of this work was to use multivariate analysis to study the effect size and the order of influence of three factors that interfere with pesticide application technology in corn crops. A 2 × 2 × 3 factorial experiment was conducted with two droplet size classes (fine and coarse), two application rates (80 and 150 L ha−1), and the presence of adjuvants (mineral oil one and two, and no adjuvant). A knapsack boom sprayer was used for the applications. Droplet deposition on the corn leaves was evaluated by detecting a tracer added to the spray via spectrophotometry and the droplet spectrum by analyzing water-sensitive papers. Univariate and multivariate statistical analyses were performed to integrate the variables analyzed. Droplet size has proven to be the most important factor in spraying planning, and the second factor is the application rate. With the association between fine droplets and higher application rates, a better performance was obtained in coverage, droplet density, and droplet deposition.
A Deus, pelas oportunidades, as bênçãos, sabedoria e por colocar sempre as pessoas certas no meu caminho. Gostaria de expressar minha gratidão a todas as pessoas que contribuíram de uma forma ou de outra forma para esta pesquisa, sem dúvida não teria concluído este trabalho sem seus aportes. Em especial gostaria de agradecer... Ao meu orientador, Prof. Dr. João Paulo A. Rodrigues Da Cunha, pelos ensinamentos, compreensão, paciência, amizade e a confiança depositada em mim, eterna gratidão.A minha co-orientadora, Prof. Dra. Denise Garcia de Santana, pelas importantes sugestões para enriquecer este trabalho, e sobretudo pelos excelentes cuidados e orientações como coordenadora do programa de pós-graduação de agronomia na primeira etapa do programa, muito obrigada pelas gestões realizadas.Aos meus caros colegas no Laboratório de Mecanização Agrícola (LAMEC), especialmente a Sergio Macedo Silva, César Zandonadi, Thales Cassemiro Alves, Heli Heros Assunção, Arthur Carlos de Oliveira, Rafael Marcão, Ernane Lemes, Mateus Gregório sem vocês teria sido impossível a execução deste trabalho.Aos meus colegas do curso, aos meus amigos muito obrigada pela acolhida, pela amizade pelas inúmeras ajudas recebidas, fizeram-me sentir em casa nestes quatro anos, especialmente a Gabriella de Freitas Alves, Joyce Peixoto, Morgana Coelho Mamede, Luciana Correia, Camila Soares, entre outros que teve o prazer de conhecer.À família Esteves-Rodrigues, pela calorosa acolhida e ficar do meu lado sempre, são minha família no Brasil. Aos meus amigos de Equador, Eveling Iñiguez e Carlitos Manosalvas, apesar da distância estiveram sempre presentes para levantar meus braços quando precisei.Aos professores do ICIAG com quem teve a oportunidade de aprender nas salas de aula, muitos desses ensinamentos vão além das ciências. À Organização dos Estados Americanos (OEA) e a CAPES, pela concessão da bolsa de estudos. À Universidade Federal de Uberlândia, à Pró-Reitoria de Pesquisa e Pós-graduação, ao Instituto de Ciências Agrarias (ICIAG), e ao Programa de Pós-graduação em Agronomia pelo suporte administrativo.Em especial, a minha família, pelo continuo incentivo e motivação, foram meu motor nestes quatro anos. "Tudo o que fizerem, façam de todo o coração, como para o Senhor, e não para os homens, sabendo que receberão do Senhor a recompensa da herança. É a Cristo, o Senhor, que vocês estão servindo".Colossenses 3:23,24 "Suba o primeiro degrau com fé. Não é necessário que você veja toda a escada. Apenas dê o primeiro passo". Martin Luther King Jr."Agricultura sem ciência é uma fazenda de porteiras fechadas". Iago Fernandes"Agradeça aos agrotóxicos por estar vivo: o futuro não é orgânico". Nicholas Vital"La agricultura de altos rendimientos es la solución y no el problema para la fauna silvestre y el medio ambiente".
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