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Desenvolvimento e crescimento do milho (Zea mays l.): avaliação de metodologias para a determinação do índice de área foliar
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Advisor(s)
Abstract(s)
Este estudo centrou-se na análise da matéria seca total (MST), índice de área foliar
(IAF) e índice de vegetação por diferença normalizada (NDVI) em duas variedades de
milho (P1441 e P0937) estabelecidas numa parcela pertencente à exploração Quinta do
Campo.
Foram recolhidas aleatoriamente 8 plantas de cada variedade aos 33, 40, 49, 64,
83, 121, 144 e 155 dias após a sementeira (DAS) para quantificação da matéria seca após
a sua secagem em estufa ventilada. Realizaram-se 8 leituras em 4 locais em cada
variedade, utilizando um ceptómetro para monitorizar as alterações do IAF ao longo do
ciclo cultural. Estes valores do IAF foram correlacionados com a biomassa e com o
NDVI. O IAF foi, ainda, estimado através da matéria seca das folhas (MSF) e da
superfície foliar específica.
Foi observada uma fraca correlação entre o IAF e a MST para o ciclo da cultura.
No entanto, existiu uma correlação positiva entre estes parâmetros até à floração. A MSF
obtida através da superfície específica foliar (210 cm2/g de folha seca) revelou ser um
bom estimador do IAF calculado pelo ceptómetro. Acedendo à plataforma “OneSoil”,
obtiveram-se imagens de NDVI ao longo do ciclo cultural, sendo que os valores deste
índice também foram correlacionados com os parâmetros mencionados. O NDVI foi
capaz de representar as alterações do IAF ao longo do ciclo, foi obtida uma melhor
correlação na variedade P 0937. Nesta variedade, os níveis mais elevados de NDVI
estiveram associados a aumentos do IAF, com o NDVI máximo atingido na fase floração,
coincidindo com o IAF máximo. Após a floração, ambos os parâmetros diminuíram
progressivamente até ao final do ciclo. Em relação à correlação entre o NDVI e a MST
os valores máximos mais elevados de NDVI até à floração também se associaram a uma
maior produção de MST no final do ciclo. Após a floração, desde o enchimento do grão
até ao final do ciclo, o NDVI diminui progressivamente. Deste modo, o NDVI pode servir
como um indicador fiável da produção de biomassa da cultura.
This study focused on the analysis of dry matter (DM), leaf area index (LAI), and normalized difference vegetation index (NDVI) in two maize varieties (P1441 and P0937) established in a plot belonging to Quinta do Campo farm. Eight plants from each variety were collected at 33, 40, 49, 64, 83, 121, 144, and 155 days after sowing (DAS) to quantify dry matter by weighing the plants after oven-drying them. Using a ceptometer, 8 readings were taken at 4 points within each variety at the specified intervals to monitor changes in LAI throughout the crop cycle and to correlate it with biomass and NDVI, as well as to estimate LAI based on leaf dry matter (LDM). A weak correlation was observed between LAI and total dry matter (TDM) over the entire crop cycle. However, there was a correlation between these parameters until flowering. Leaf dry matter, calculated using a specific leaf area (SLA) of 200 m²/g of dry leaf, proved to be a good estimator of LAI calculated with the ceptometer. Accessing the “OneSoil” platform, NDVI images were obtained throughout the cycle, and these NDVI levels were also correlated with the parameters mentioned. NDVI was able to represent changes in LAI over the cycle; however, a better correlation was found in variety P0937. In this variety, higher NDVI levels were associated with increases in LAI, with maximum NDVI reached at flowering, coinciding with maximum LAI. After flowering, both parameters decreased progressively until the end of the cycle. Regarding the correlation between NDVI and total dry matter (TDM), the highest NDVI values until flowering were also associated with greater TDM production at the end of the cycle. After flowering, from grain filling to the end of the cycle, NDVI gradually decreased, serving as a reliable indicator of the crop’s photosynthetic activity.
This study focused on the analysis of dry matter (DM), leaf area index (LAI), and normalized difference vegetation index (NDVI) in two maize varieties (P1441 and P0937) established in a plot belonging to Quinta do Campo farm. Eight plants from each variety were collected at 33, 40, 49, 64, 83, 121, 144, and 155 days after sowing (DAS) to quantify dry matter by weighing the plants after oven-drying them. Using a ceptometer, 8 readings were taken at 4 points within each variety at the specified intervals to monitor changes in LAI throughout the crop cycle and to correlate it with biomass and NDVI, as well as to estimate LAI based on leaf dry matter (LDM). A weak correlation was observed between LAI and total dry matter (TDM) over the entire crop cycle. However, there was a correlation between these parameters until flowering. Leaf dry matter, calculated using a specific leaf area (SLA) of 200 m²/g of dry leaf, proved to be a good estimator of LAI calculated with the ceptometer. Accessing the “OneSoil” platform, NDVI images were obtained throughout the cycle, and these NDVI levels were also correlated with the parameters mentioned. NDVI was able to represent changes in LAI over the cycle; however, a better correlation was found in variety P0937. In this variety, higher NDVI levels were associated with increases in LAI, with maximum NDVI reached at flowering, coinciding with maximum LAI. After flowering, both parameters decreased progressively until the end of the cycle. Regarding the correlation between NDVI and total dry matter (TDM), the highest NDVI values until flowering were also associated with greater TDM production at the end of the cycle. After flowering, from grain filling to the end of the cycle, NDVI gradually decreased, serving as a reliable indicator of the crop’s photosynthetic activity.
Description
Dissertação, Mestrado, Engenharia Agronómica, Instituto Politécnico de Santarém, Escola Superior Agrária, 2025
Keywords
Zea mays índice área foliar ceptómetro NDVI produtividade leaf area index ceptometer yield
Pedagogical Context
Citation
Mendonça, A.F.M.S.V. (2025). Desenvolvimento e crescimento do milho (Zea mays l.): avaliação de metodologias para a determinação do índice de área foliar. Dissertação de Mestrado na área da Engenharia Agronómica, apresentada na Escola Superior Agrária de Santarém. http://hdl.handle.net/10400.15/5887