Spatial and temporal relationship between aboveground biomass and the enhanced vegetation index for a mixed pasture in a Brazilian integrated crop livestock system

Integrated Crop Livestock (iCL) systems have been adopted in some areas of Brazil to recover degraded pasture and mitigate greenhouse gas emissions (GHG), using iCL management to improve soil and grass quality, increase grass availability, and raise the stocking rate of pasture areas. Plant production data can be retrieved from field measurements as well as from remote sensing products by assimilation using Vegetation Indices (VIs). However, little information is available about the relationship between plant biomass growth in mixed pastures in Brazil and Enhanced Vegetation Index (EVI) data, which can be used as an input in biogeochemical models like Daycent to simulate soil carbon and nitrogen flux dynamics spatially and temporally in these systems. Therefore, the aim of this study was to analyze the spatial and temporal relationship between mixed pasture aboveground biomass and EVI from the Moderate Resolution Imaging Spectroradiometer sensor. The study area corresponds to an iCL system (Pasture Urochloa ruziziensis - Brachiaria and the Pennisetum glaucum - Millet with livestock in succession with soybean), located on a farm in western São Paulo state. The study area was split into four plots of 50 hectares each, totaling 200 hectares. Temporally, EVI data was very sensitive to aboveground biomass as it responded to iLC management applied in the study area through time. The EVI response for the spatial variability was higher for those plots with medium clay content with an average correlation of 97 %. On the other hand, a lower spatial correlation was seen on plots with a higher sand content with an average correlation of 37 %. For the spatial variability, further analysis with other variables should be included to understand this high variation on spatial scale.