Uso do aplicativo Canopeo para estimativa da massa de forragem do capim-elefante consorciado ou não com cunhã

Abstract

Destructive assessment methods to estimate forage mass, although considered more accurate, are more labor intensive compared to non-destructive methods. Canopeo is a mobile app developed at the University of Oklahoma for Android and IOS systems and has been considered a good tool for estimating canopy coverage. This study aimed to evaluate the use of Canopeo to estimate forage mass of Elephant grass [Cenchurus purpureus (Schumach.) Morrone syn. Pennisetum purpureum Schum.] of different sizes intercropped or not with butterfly pea (Clitoria ternatea L.). The experiment was conducted at the Carpina Sugarcane Experimental Station (EECAC)/Federal Rural University of Pernambuco (UFRPE) between 2019 and 2022. Four elephant grass genotypes, being two of tall size (IRI-381 and Elephant B) and two dwarf size (Taiwan A-146 2.37 and Mott) in intercropped or not with cunhã were harvested every 60d. Data from two representative harvests in the rainy season of 2019 and 2022 were considered. Images were collected using a cell phone with a camera attached at the top and in the profile of the vegetation at a representative point of the average condition of each plot to estimate the green cover and percentage of pixel of green color in the canopy profile. The regression equations obtained to estimate the total forage mass generally showed the best R2 value in the intercropped condition during the 2019 rainy season, with R² 0.71. For estimates of total forage mass from the percentage of green in the canopy profile, the R² varied from 0.58 and 0.70 in the first year and from 0.62 to 0.63 in the the second year. The values of green cover of the top of the vegetation obtained with Canopeo application presented, in general, a better level of association with the total forage mass and green biomass in comparison with the measurements carried out from the canopy profile. The Canopeo application can be considered an interesting tool to estimate the total forage mass and leaf mass of elephant grass genotypes intercropped or not with butterfly pea.