ABSTRACT Global consumption of oilseeds has been growing progressively in the last five growing seasons, in which soybean represents 60% of this sector. Thus, in order to maintain a high production in the region of Rio Verde, State of Goiás, against the phytopathological problems, this study aimed to define the best spectral range for the detection of H. glycines and P. brachyurus by linear regressions in soybean at R3 stage, as well as the elaboration of mathematical models through multiple linear regressions. For this, soil and root were sampled in the experimental area, as well as a flight was performed with the Sentera sensor. Data were used for the elaboration of regressions and for the validation of 2 mathematical models. Significant values were observed in simple linear regression only for cysts, in the visible range, with a good R² value for the Green, Red and 568 nm bands, to nonviable cysts. When working with the stepwise statistics, better results are found for H. glycines, which now has an R²(aj) of 0.7430 and P. brachyurus is then detected. From the mathematical model obtained with the multiple linear regression for non-viable cysts with an R²(aj) of 0.7430, it is possible to detect the spatial distribution of nematodes across the soybean field, in order to perform a localized management, optimizing the applications. Good results are also possible using the mathematical model obtained by simple linear regression.

ABSTRACT Images from unmanned aerial vehicles (UAV) can serve as a baseline for studies in weed science, complementing observations obtained in the ground. The objective of this work was to determine soybean (Glycine max (L.) Merr.) plant injury caused by pre-emergence herbicides in sandy and clayey soils, using a low-cost UAV. The experiment was conducted in a randomized complete block design, with four replicates and seven treatments consisted of herbicides (diclosulam, chlorimuron, sulfentrazone, flumioxazin, and S-metolachlor), hand weeded and untreated treatments. Ground-based evaluations were carried out to assess soybean crop injury, plant stand, leaf chlorophyll content, plant height, canopy distance and grain yield. Images were taken using a UAV equipped with an RGB (red green and blue) camera. Soybean plants sprayed with diclosulam had lower plant reflectance in the R (98.9), G (147.1) and B (74.3) range than the other treatments in sandy soil. In clayey soil, hand weeded treatment had higher plants (30.8 cm) and untreated favored smaller plants (24.9 cm) compared to herbicide treatments. In sandy soil, soybean yield of all treatments was similar, however in clayey soil, soybean yield treated with chlorimuron and flumioxazin was higher than 5000 kg ha-1 and better than the others treatments. The nutrient-poor soil (sandy) may have aggravated the plant injury caused by herbicides and explain the lower yield observed compared to clayey soil. It was determined soybean plant injury caused by pre-emergence herbicides with the use of unmanned aerial vehicles, providing complementary results to ground-based measurements, indicating the potential of this technology for low-cost evaluations in weed science.

RESUMEN Para mejorar el desarrollo de cultivos, se recomiendan sustratos comerciales indistintamente del tipo de cultivo y/o variedad sin considerar sus características y necesidades. Por lo tanto, se debe estudiar su composición y condición nutricional para cada tipo de planta en su etapa inicial. El objetivo de este estudio fue evaluar el desarrollo del sistema de brotes y raíces de dos cultivares de lechuga producidos en 10 sustratos diferentes. Los cultivares Great Lakes y Simpson Black Seed se evaluaron en 10 sustratos formulados mezclando un sustrato comercial, compuestos orgánicos (cerdos, ganado y aves de corral) y bagazo de caña de azúcar. El cultivar Great Lakes tuvo un mayor desarrollo de la parte aérea, mientras que el cultivar Simpson Black Seed tuvo un sistema de raíces más robusto. El sustrato que contenía los residuos provenientes de cerdos y aves fue el que favoreció el desarrollo de la parte aérea de las plántulas y la lechuga, mientras que los que contenían el 33% del bagazo de caña de azúcar fueron los que favorecieron el desarrollo del sistema radicular. El sustrato comercial utilizado de forma aislada, mostró el rendimiento más bajo.

ABSTRACT To improve crop development, commercial substrates are recommended without distinction for different crops and/or varieties without considering their characteristics and needs; therefore, their composition and nutritional condition must be studied for each type of plant in its initial formation. The objective of this study was to evaluate the development of shoot and root systems of two lettuce cultivars produced in 10 different substrates. Great Lakes and Simpson Black Seed cultivars were evaluated in 10 substrates formulated by mixing a commercial substrate, organic compounds (swine, cattle, poultry) and sugarcane bagasse. Great Lakes cultivar had a higher development of the aerial part, whereas Simpson Black Seed cultivar had a more robust root system. The substrate with swine and poultry favored the development of the aerial part of the seedlings and lettuce, while the substrates with 33% of sugarcane bagasse improved the development of the root system. The commercial substrate used in isolation showed the lowest performance.

RESUMO: A soja é uma das principais espécies de planta cultivadas no mundo. Todavia, perdas de produtividade são ocasionadas por vários tipos de estresses, incluindo os nematoides H. glycines e P. brachyurus. Como objetivo, buscou-se determinar a melhor banda espectral para a detecção do H. glycines e P. brachyurus com o uso de modelos de regressões lineares simples e definir um modelo matemático de regressão linear múltiplo para sua detecção, no início do florescimento (R1). Para isto, foram definidos nove pontos de coleta em cinco reboleiras, totalizando 45 pontos. As coletas foram feitas em um padrão específico de distâncias, de forma a ter amostras com tipos variados de populações de nematoides. Foram realizados voos com o Phantom 4 Advanced, Sequoia e Sentera sobre cada uma das reboleiras. O comprimento de onda do vermelho melhor explicou a variabilidade dos dados para H. glycines no solo e na raiz, bem como dos juvenis de segundo estádio no solo. Para P. brachyurus, a RedEdge da Sentera foi a que explicou melhor a variabilidade dos dados para nematoide na raiz e a NIR da Sequoia a que melhor explicou para juvenis no solo. Quando se utilizou um modelo matemático para a detecção do P. brachyurus e H. glycines, percebe-se uma grande melhora no R² e p-valor com relação às regressões lineares simples. No início da floração (R1), a refletância espectral da soja foi associada ao número de H. glycines e P. brachyurus no solo e nas raízes, usando sensores de baixo custo e multiespectrais.

ABSTRACT: Soybean is one of the main crop species grown in the world. However, there is a decline in productivity due to the various types of stress, including the nematodes Heterodera glycines and Pratylenchus brachyurus. The objectives were to determine the best spectral band for detecting H. glycines and P. brachyurus at the beginning of flowering (R1). Soil and root sampling was conducted at nine sampling sites in each of the five nematode-infested regions, totaling 45 sampling points. Flights were made at all regions using Phantom 4 Advanced, Sequoia and 14-band customized Sentera. For H. glycines, the red spectral band best explained the variability on soil and root nematode counts as well as the second stage of juveniles in soil. For P. brachyurus, Sentera RedEdge best explained the variability in root nematode counts and Sequoia NIR best explained soil juveniles. A multiple linear regression model using spectral data for detecting P. brachyurus and H. glycines improved R² compared to simple linear regressions. At flowering growth stage (R1), soybean spectral reflectance was associated with the number of H. glycines and P. brachyurus on soil and roots using low-cost and multispectral sensors.

RESUMEN El cultivo de lechuga en un sistema hidropónico es una alternativa para optimizar su producción. La lechuga es un alimento importante, ya que es una de las verduras más consumidas en Brasil. El objetivo de este estudio fue evaluar el comportamiento agronómico de cultivares comerciales de lechuga bajo una única solución nutritiva en un sistema hidropónico. El experimento se realizó en condiciones de invernadero. El diseño experimental fue completamente al azar con cinco repeticiones. Los tratamientos estaban compuestos por cultivares comerciales de lechuga (Americana Great Lakes, Rafaela-Americana y Simpson Black Seed). Al momento de la cosecha se evaluaron los siguientes parámetros: número de hojas, longitud de hojas y raíces, masa fresca de brotes y raíces, y diámetro del tallo. Los datos recopilados fueron sometidos a una ANAVA. El cv. Rafaela-Americana presentó mayor longitud de hoja. Los cultivares evaluados no presentaron diferencias significativas en el número de hojas, masa verde aérea, masa de raíz verde, longitud de raíz y diámetro del tallo. Los cultivares mostraron variaciones similares en el número de hojas, masa verde aérea, masa de raíz verde, longitud de raíz y diámetro del tallo. El cultivar Rafaela-Americana presentó un desempeño superior en el desarrollo de la longitud de la hoja con respecto a los otros cultivares.

ABSTRACT The cultivation of lettuce in a hydroponic system is an alternative to optimize the production. Lettuce is an important food, being one of the most consumed vegetables in Brazil. The objective of this study was to evaluate the agronomic behavior of commercial cultivars of lettuce under a single nutritive solution in a hydroponic system. The experiment was carried out under greenhouse conditions. The experimental design was completely randomized, with five replicates. The treatments were composed of commercial lettuce cultivars (Americana Great Lakes, Rafaela-Americana, and Simpson Black Seed). At the time of harvest, the following parameters were evaluated: number of leaves, length of leaves and roots, fresh mass of shoot and root, and stem diameter. The collected data were submitted to an ANOVA. The cv. Rafaela-Americana presented higher leaf length. The evaluated cultivars did not present significant differences in the number of leaves, aerial green mass, green root mass, root length, and stem diameter. The cultivars showed similar variations in the number of leaves, aerial green mass, green root mass, root length, and stem diameter. The cultivar Rafaela-Americana presented a superior performance in the development of leaf length regarding the other cultivars.

ABSTRACT Soil erosion is a serious environmental problem that can cause numerous types of damage to society and the environment, and thus require preventive measures. The objective of this study was to evaluate soil erosion vulnerability in the southern region of the Meia Ponte watershed, Goias, Brazil, considering two situations: natural and anthropic cover conditions. For the analysis, we used remote sensing data represented by several parameters: lithology, soil class, slope, rain intensity, vegetation index, vicinity of roads, and land use and occupation. For each variable, we established a scale of weights according to erosive susceptibility for natural and anthropogenic environments. Multicriteria analysis, which allows the combination of qualitative and quantitative information in the analysis of erosive susceptibility, was used through the relationship between soil use and land occupation. In the southern part of the Meia Ponte River watershed, the anthropic factor showed greater influence. The factors that increase erosive susceptibility were soil use and occupation, low vegetation index, and high slope. The southern part of the Meia Ponte watershed presents medium natural erosive susceptibility in most of the study area.

RESUMEN La erosión de los suelos es un grave problema ambiental que puede ocasionar numerosos daños a la sociedad y al medio ambiente, siendo necesario la adopción de medidas preventivas. Este estudio tuvo por objetivo evaluar la vulnerabilidad erosiva de los suelos en la región sur de la cuenca Meia Ponte, Goiás, considerando dos situaciones: condiciones de cobertura natural y antrópica. Para la realización de los análisis, se utilizaron datos de sensoriamiento remoto representados por diversos parámetros: litología, clase de suelo, declividad, intensidad de lluvia, índice de vegetación, cercanías de vías y uso y ocupación del suelo. Se establecieron para cada variable, una escala de pesos de acuerdo con susceptibilidad erosiva para el medio natural y otra antrópica. Se utilizó el análisis multicriterio, por medio de la relación entre las actividades de uso y ocupación del suelo, la cual permite combinar informaciones cualitativas y cuantitativas en análisis en cuanto a la susceptibilidad erosiva. En la parte sur de la cuenca del Río Meia Ponte, el factor antrópico obtuvo mayor influencia. Los factores que aumentaron susceptibilidad erosiva fueron el uso y ocupación del suelo, bajo índice de vegetación y la alta declividad. La parte sur de la cuenca Media Ponte, presenta susceptibilidad erosiva natural media en la mayor parte del área de estudio.