Lúcio André de Castro Jorge

Avaliação do sistema radicular da cana-de-açúcar por diferentes métodos

To select a method for the evaluation of a root system the research goals, crop of interest, and its growth conditions must be taken into consideration. The study of roots is highly important in the understanding of various phenomena of the shoot growth and development, but requires an extremely careful proceeding since evaluation methods are laborious and the roots are affected by the physiochemical variability of the soil. The objective of this research was to compare five evaluation methods for the root systems of two sugar-cane varieties at four depths, in two harvest systems: green cane harvesting and manual harvesting of burnt cane. Four methods were compared to the monolith method with dry matter quantification: monolith with length measurement, auger method, profile wall with length measurement by digital image analysis and profile wall with counting of the root number. Linear regressions expressed the relationship among the methods adequately, except in relation to the auger method. The profile wall methods were the most appropriate to detect differences among treatments.

Grapevine root distribution in drip and microsprinkler irrigation

ABSTRACT: Grape ( Vitis vinifera L.) yield and its quality are dependent of the status of the root system.Root distribution information is also valuable for soil and water management. An analysis of methods toevaluate the root distribution of grapevines for both, drip and microsprinkler irrigation in a Typic Acrustoxis presented for the table grape cv. Italia grafted on the rootstock IAC-313, in northeastern Brazil. Measuredroot parameters using the monolith method were root dry weight (D w ) and root length density (L v ), while rootarea (A p ) was estimated using the soil profile method in combination with digital image analysis. For bothirrigation systems, roots were present to the 1 m soil depth and extended laterally to 1 m distance from thetrunk, but grapevines irrigated by microsprinkler showed greater root presence as the distance from the trunkincreased. Values of A p were reasonably well correlated to D w and L v . However, correlation values werehigher when fractional root distribution was used. The soil profile method in combination with image analysistechniques, allows proper grapevine root distribution evaluation.Key words:

Distribuição do sistema radicular de uma cultura de aveia forrageira

Forage oat root distribution was evaluated through the application of the methods of the volumetric ring, of the nail plate, of the auger, and of image processing. The crop was grown on a Dark Red Latosol, submitted to two different treatments in relation to water avalilability: 1. Mantaining at least 50% of the soil available water, and 2. Mantaining 80%. Three samplings were perfoemed, 25, 60, and 115 days after emergence. Oat roots were concentrated in the top soil layer, about 90% from 0 to 20 cm depth. Results of root quntification show, in general, distinct with respect to treatment, methodology and sampling date. Correlations were found between data of dry root weigth and root presence. The root variability in the soil depended on the method of evaluation. The lowest coefficients of variation were found for the auger method, indicating that the lowest variability of root distribution has a greater relation to sample volume then on the number of sampling points.

Distribuition of maize root system in a kanduidalfic eutrudox soil: I. Comparison of methodologies

A distribuicao do sistema radicular do milho (Zea mays, L.) em terra roxa estruturada foi avaliada pelos metodos do trado, do cilindro volumetrico e de processamento de imagens, esse ultimo um novo metodo auxiliar no estudo destes sistemas. A amostragem do sistema radicular foi definida num plano perpendicular a linha da cultura, em regioes de 20 X 20 cm, abrangendo uma area total de 100 X 100 cm. Os resultados da quantificacao radicular mostraram uma maior concentracao de raizes na camada de 0-20 cm, cerca de 70% de massa seca para uma presenca radicular de aproximadamente 40%. O metodo de processamento de imagens mostrou-se como uma ferramenta poderosa no estudo detalhado de sistemas radiculares.

Public-domain software for root image analysis

Procurando maior eficiencia no estudo de raizes, sistemas computacionais tem sido desenvolvidos para analisar imagens digitais. O ImageJ e o Safira sao sistemas de dominio publico que podem ser utilizados na analise de raizes lavadas. Porem, supoe-se que ha diferencas nos atributos radiculares determinados por meio do ImageJ e Safira. Este estudo foi realizado para comparar valores de comprimento e area superficial de raizes, obtidos com os dois sistemas, com os valores alcancados por meio do metodo de referencia. Amostras de raizes foram coletadas em bananal em areas de Cambissolo Haplico carbonatico tipico (CXk), mais raso, e de Cambissolo Haplico Ta eutrofico tipico (CXve), mais profundo, em seis camadas e cinco repeticoes. As raizes foram escaneadas e os sistemas ImageJ e Safira foram utilizados para determinar comprimento e area superficial radicular. Utilizando o metodo da intersecao modificado por Tennant como referencia, valores de comprimento e area obtidos pelos sistemas foram analisados a partir do coeficiente de correlacao de Pearson e comparados pelo intervalo de confianca e pelo teste t. Ambos os sistemas apresentaram coeficiente de correlacao positivo com o metodo de referencia para medidas de comprimento e area superficial em CXk e CXve. O coeficiente de correlacao variou de 0,54 a 0,80, com menor valor observado para o ImageJ na determinacao da area superficial de amostras coletadas no CXve. O IC (95 %) revelou que as medidas de comprimento radicular com o Safira nao diferiram do metodo de referencia no CXk (-77,3 a 244,0 mm). Quanto a area superficial, o Safira nao diferiu do metodo de referencia, tanto para amostras coletadas em CXk (-530,6 a 565,8 mm2) como nas provenientes de CXve (-423,1 a 612,1 mm2). Ja as medidas feitas com o ImageJ diferiram do metodo de referencia, com valores subestimados de comprimento e area superficial radicular em amostras coletadas em CXk e CXve. Os dois sistemas permitem identificar aumento ou diminuicao no comprimento e na area superficial de raizes lavadas. Porem, o Safira resulta em valores de comprimento e de area superficial radicular mais proximos aos obtidos com o metodo de referencia.

Spectral reflectance of satellite images using geostatistics methods to estimate growth and cotton yield

The objective of this study was the spatial identification of the NDVI index and cotton yield distributions through different crop phenological stages using geostatistical methods in Goiás state, Brazil. The experiment was carried out in a commercial field with 47.4 ha, in 80x80m georeferenced grid with 74 plots. Yield monitor data and multispectral satellite images at 56 m spatial resolution were collected in a rainfed cotton field in two dates to monitor the plant vigor. Satellite images of AWiFS sensor were acquired on 08/02/2011 and 01/04/2011, during the first flowering and fruiting cotton stages, respectively, corresponding to 70 and 120DAE (days after emergence). Measures of canopy reflectance, plant height and leaf nitrogen content were determined and cotton yield was obtained by mechanical harvest in August, 2011. Data were analyzed using descriptive statistics, correlation and geostatistical analyses by building and setting semivariograms and kriging interpolation. Best correlation was found between NDVI and cotton yield at 120DAE. At first flowering, the NDVI and cotton yield showed strong spatial dependence, while for 120DAE there was no dependence, probably due to the enlargement of vegetated coverage. There were similarities in the bottom left of the study area with high values of NDVI, as well as the highest values of cotton yield due to excellent plant vigor in the cotton flowering stage. Identifications of spatial differences were possible using geostatistical methods with remote sensing data obtained from medium resolution satellite images, allowing to identify distinct stages of plant growth and also to predict the cotton yield.

Insights and recommendations of use of UAV platforms in precision agriculture in Brazil

The Interest in Unmanned Aerial Vehicles (UAVs) has grown around the world and several efforts are underway to integrate UAV operations routinely and safely into remote sensing applications, specially applied in precision agriculture. Reviewing the use of UAV in agriculture it shows limitations and opportunities. So the challenges of UAV platforms for remote sensing and precision agriculture were identified during a real case studied at a citrus area to monitor the HLB (Huanglongbing) infestation. Recommended actions for moving forward were identified and showed that is possible to use UAVs for detection of crop diseases with high precision.

Parameter estimation for ridge detection in images with thin structures

This paper presents an analysis of four ridge detectors in images with thin structures: plant root images and retinal images. Two proposed detectors and two detectors from the literature are used. We estimate the optimal parameters for each detector for the two applications using a ROC curve similar approach. Simulated images of plant roots and retinal images are used. The optimal parameters are estimated and then used in real images. We conclude that the proposed detector based on mathematical morphology and the one based on the steerable filter are the best for both set of images.

Ridge linking using an adaptive oriented mask applied to plant root images with thin structures

A ridge linking algorithm and its application to plant root images is presented. The idea is an improvement of an edge linking algorithm where we explore local directional information. The experimental results show that we obtain good connections between ridge segments which tends to maintain the connectivity of structures like plant roots.

Aerial image mosaics built using images with vegetation index pre-calculated

Precision agriculture (PA) has offered a multitude of benefits to farmers, such as cost reduction, accuracy and speed in decision making. Among the tools that work with PA, the aerial image mosaics have key role in accurate mapping of diseases and pests in crops. A mosaic is the combination of multiple images, creating a new image that covers the property or plots accurately. One of the important analysis for farmers is based on the properties of the reflectance in each range of the electromagnetic spectrum of vegetation. Performing mathematical combinations of the different spectral bands has a better understanding of the spectral response of the vegetation. These combinations are called vegetation index (VI) and are useful for the control of the biomass, water content in leaf, chlorophyll content and others. It is usually calculated VI after the construction of the mosaic, as well the farmer has an accurate analysis of its vegetation. However, building a mosaic of images, it has a high computational cost, taking hours to complete and then apply the VI and to have the first test results. In order to reduce the computational cost of this process, this work aims to present a mosaic of images constructed from images with the VI already pre-calculated providing faster analysis to the farmer, given the fact that applying VI on the image came a this reduction in density image and thus have the gain in computational cost to build the mosaic.