Diagnosis of nitrogen nutrition in common bean leaves by digital image analysis

O objetivo deste trabalho foi avaliar o uso da análise digital de imagens na diagnose nutricional de N no feijoeiro. Foram avaliados quatro tratamentos, em que se combinaram duas doses de N e de P aplicadas ao solo. Na emissão de vagens, determinou-se o índice de clorofila Falker, digitalizaram-se as imagens dos trifólios e determinou-se o teor foliar de N. Nas imagens, foi atribuída uma nota com o programa AFSoft, baseada na área ocupada por padrões de verde. O teor foliar de N correlacionou-se ao índice de clorofila Falker e à nota atribuída com o AFSoft, mas a correlação entre o índice de clorofila e a nota AFSoft foi superior.The objective of this work was to evaluate the use of digital image analysis for the N nutritional diagnosis in common bean. Four treatments combining two levels of N and P applied to the soil were evaluated. At the pod setting stage, the Falker chlorophyll index was determined, the images of trifoliates were scanned, and leaf‑N concentration was measured. In the images, a note with the software AFSoft was assigned based on the area occupied by green standards. Leaf‑N content correlated to the Falker chlorophyll index and the AFSoft note, but the correlation between chlorophyll index and AFSoft note was higher