Resumo -O objetivo deste trabalho foi estimar e mapear as áreas com as culturas de soja e milho, no Paraná, com uso de imagens multitemporais EVI/Modis. Foram avaliados os anos-safra de 2004/2005 a 2007/2008. Em razão da alta dinâmica temporal e da heterogeneidade de datas de semeadura das culturas no estado, foram utilizadas cenas que contemplavam as fases de pré-plantio e de desenvolvimento inicial das culturas, para gerar a imagem de mínimo EVI (IMIE), e cenas que consideravam o pico vegetativo das culturas, para gerar a imagem de máximo EVI (IMAE). Estas imagens foram utilizadas para gerar a composição colorida RGB (R, IMAE; GB, IMIE), o que permitiu a confecção de máscara das áreas com soja e milho. As estimativas das áreas de máscara por município foram comparadas com dados oficiais de produção agrícola municipal, tendo-se observado bons ajustes (R²>0,84, d>0,95, c>0,85) entre os dados. Para a avaliação da exatidão espacial das máscaras, imagens Landsat-5/TM e AWiFS/IRS foram usadas como referência para construção da matriz de erros. Os resultados obtidos são indicativos de que a metodologia proposta é altamente eficiente e pode ser utilizada para mapeamento dessas culturas.Termos para indexação: classificação de imagens, distribuição espacial de culturas, índice de vegetação, mapeamento, previsão de safras, sensoriamento remoto. Estimation of summer crop areas in the state of Paraná, Brazil, using multitemporal EVI/Modis imagesAbstract -The objective of this work was to estimate and map crop areas with soybean and corn in the state of Paraná, Brazil, using EVI/Modis images. The crop seasons from 2004/2005 to 2007/2008 were evaluated. Due to the high temporal dynamics and difference in sowing dates of the cultures within the state, scenes containing the pre-planting and initial crop development phases were used to obtain the minimum EVI image (IMIE), and scenes at the peak of the crop cycle were used to obtain the maximum EVI image (IMAE). These images were used to generate the RGB color composition (R, IMAE; GB, IMIE), which allowed for the creation of masks of the areas planted with soybean and corn. The estimation of masked areas by municipality was compared with the municipal agricultural production official data, and good fits (R²>0. 84, d>0.95, c>0.85) were observed between data. For spatial accuracy assessment, Landsat-5/TM and AWiFS/IRS images were used as references to build the error matrix. The obtained results indicate that the proposed methodology is highly efficient and may be used as a model for cropland mapping.
It is expected that Brazil could play an important role in biojet fuel (BJF) production in the future due to the long experience in biofuel production and the good agroecological conditions. However, it is difficult to quantify the techno-economic potential of BJF because of the high spatiotemporal variability of available land, biomass yield, and infrastructure as well as the technological developments in BJF production pathways. The objective of this research is to assess the recent and future technoeconomic potential of BJF production in Brazil and to identify location-specific optimal combinations of biomass crops and technological conversion pathways. In total, 13 production routes (supply chains) are assessed through the combination of various biomass crops and BJF technologies. We consider temporal land use data to identify potential land availability for biomass production. With the spatial distribution of the land availability and potential yield of biomass crops, biomass production potential and costs are calculated. The BJF production cost is calculated by taking into account the development in the technological pathways and in plant scales. We estimate the techno-economic potential by determining the minimum BJF total costs and comparing this with the range of fossil jet fuel prices. The techno-economic potential of BJF production ranges from 0 to 6.4 EJ in 2015 and between 1.2 and 7.8 EJ in 2030, depending on the reference fossil jet fuel price, which varies from 19 to 65 US$/GJ across the airports. The techno-economic potential consists of a diverse set of production routes. The Northeast and Southeast region of Brazil present the highest potentials with several viable production routes, whereas the remaining regions only have a few promising production routes. The maximum techno-economic potential of BJF in Brazil could meet almost half of the projected global jet fuel demand toward 2030. K E Y W O R D Saviation, bioenergy costs, bioenergy potential, biofuels, geographic information system, land availability, land use, renewable jet fuels, techno-economic assessment | 157 CERVI Et al.
The current system used in Brazil for sugarcane (Saccharum officinarum L.) crop forecasting relies mainly on subjective information provided by sugar mill technicians and on information about demands of raw agricultural products from industry. This study evaluated the feasibility to estimate the yield at municipality level in São Paulo State, Brazil, using 10-day periods of SPOT Vegetation NDVI images and ECMWF meteorological data. Twenty municipalities and seven cropping seasons were selected between 1999 and 2006. The plant development cycle was divided into four phases, according to the sugarcane physiology, obtaining spectral and meteorological attributes for each phase. The most important attributes were selected and the average yield was classified according to a decision tree. Values obtained from the NDVI time profile from December to January next year enabled to classify yields into three classes: below average, average and above average. The results were more effective for 'average' and 'above average' classes, with 86.5 and 66.7% accuracy respectively. Monitoring sugarcane planted areas using SPOT Vegetation images allowed previous analysis and predictions on the average municipal yield trend. Key words: NDVI, remote sensing, data mining, crop forecasting Estimativa de produtividade da cana-de-açúcar por meio de séries temporais de imagens spot vegetation RESUMO: O atual sistema de previsão de safras para a cultura da cana-de-açúcar (Saccharum officinarum L.) usado no Brasil depende, em boa parte, de informações subjetivas, baseadas no conhecimento de técnicos do setor sucroalcooleiro e em informações sobre demanda de insumos na cadeia produtiva. Avaliou-se o uso de imagens decendiais de NDVI do sensor SPOT Vegetation e variáveis meteorológicas do modelo do ECMWF para inferir sobre os dados de produtividade oficiais registrados em municípios e safras previamente selecionados. Foram selecionados 20 municípios e sete safras compreendidas entre o período de 1999 e 2006. O ciclo de desenvolvimento da cultura foi dividido em quatro fases, de acordo com a fisiologia, gerando para cada fase atributos espectrais e meteorológicos. Foram selecionados os atributos mais relevantes para a classificação da produtividade média municipal e, por meio de árvore de decisão, a produtividade média municipal foi classificada. Valores extraídos do perfil temporal do NDVI entre os meses de dezembro e janeiro permitiram classificar a produtividade em três classes: abaixo da média, média e acima da média. Os resultados foram mais efetivos para as classes "média" e "acima da média", com acertos de 86,5 e 66,7%, respectivamente. O monitoramento de áreas canavieiras do estado de São Paulo por meio de imagens SPOT Vegetation permitiu inferir sobre a tendência da produtividade média municipal previamente. Palavras-chave: NDVI, sensoriamento remoto, mineração de dados, previsão de safras
Spectral information is well related with agronomic variables and can be used in crop monitoring and yield forecasting. This paper describes a multitemporal research with the sugarcane variety SP80-1842, studying its spectral behavior using field spectroscopy and its relationship with agronomic parameters such as leaf area index (LAI), number of stalks per meter (NPM), yield (TSS) and total biomass (BMT). A commercial sugarcane field in Araras/SP/Brazil was monitored for two seasons. Radiometric data and agronomic characterization were gathered in 9 field campaigns. Spectral vegetation indices had similar patterns in both seasons and adjusted to agronomic parameters. Band 4 (B4), Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), and Soil Adjusted Vegetation Index (SAVI) increased their values until the end of the vegetative stage, around 240 days after harvest (DAC). After that stage, B4 reflectance and NDVI values began to stabilize and decrease because the crop reached ripening and senescence stages. Band 3 (B3) and RVI presented decreased values since the beginning of the cycle, followed by a stabilization stage. Later these values had a slight increase caused by the lower amount of green vegetation. Spectral variables B3, RVI, NDVI, and SAVI were highly correlated (above 0.79) with LAI, TSS, and BMT, and about 0.50 with NPM. The best regression models were verified for RVI, LAI, and NPM, which explained 0.97 of TSS variation and 0.99 of BMT variation. Key words: NDVI, vegetation index, biomass, field spectroscopy, temporal evolution VARIÁVEIS ESPECTRAIS E INDICADORES DE DESENVOLVIMENTO E PRODUTIVIDADE DA CANA-DE-AÇÚCARRESUMO: A informação espectral tem boa relação com variáveis agronômicas e pode contribuir com informações para o monitoramento, acompanhamento e previsão de safras. O presente trabalho descreve a análise multitemporal do comportamento espectral da variedade de cana-de-açúcar SP80-1842 e a relação com variáveis agronômicas como índice de área foliar (IAF), número de perfilhos por metro (NPM), produtividade (TCH) e biomassa total (BMT). Nas safras 2000/2001 e 2001/2002, um talhão comercial, localizada no município de Araras/SP foi monitorado em nove campanhas de coleta de dados radiométricos e agronômicos. O comportamento temporal das variáveis espectrais acompanhou o comportamento das variáveis agronômicas. A banda 4 (B4), o índice de vegetação da razão simples (SR), o índice de vegetação por diferença normalizada (NDVI) e o índice de vegetação ajustado ao solo (SAVI) aumentaram seus valores até o fim da fase de crescimento vegetativo, aproximadamente até os 240 dias após o corte, a partir do qual os valores se estabilizaram e diminuíram em função da entrada da cultura na fase de maturação. A banda 3 (B3) e o índice de vegetação da razão (RVI) tiveram queda em seus valores desde o início do ciclo, com posterior estabilização e aumento em seus valores devido ao aumento da quantidade de palha e da queda da biomassa foliar. As variáveis espectrais B3, RVI, NDVI e SAVI tiv...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.