Evaluation of pasture degradation through vegetation indices of the main livestock micro-watersheds in the Amazon region (NW Peru)

Abstract

Pastures provide different ecosystem services, such as carbon dioxide fixation, are indicators of climate change and prevent soil erosion. However, anthropogenic activities degrade and decrease soil diversity. Therefore, the objective was to evaluate pasture degradation using vegetation indices. For this purpose, the floristic composition was evaluated by means of linear transects (50 m) to determine the percentage of area covered by forages and weeds; the Normalized Vegetation Index (NDVI) and the Pasture Vegetation Cover (PVC) assessment methodology were used to determine pasture degradation, and the chemical properties of the soils were characterized. The degradation map showed that the range ''S4-Strongly degraded (CVP, <40%) for the Pomacochas micro-watershed is 2.60% (93.43 ha); however, in Ventilla, 0.40% (8.95 ha) was obtained. An equation was generated from a multiple linear regression model and a principal component analysis (PCA) of the main regressor variables. The results were obtained for both micro-watersheds with an R2 greater than 60% determined by CVP + Bands 3, 4, 5, 6, 8 and pH. In addition, the PCA showed that at acidic pH, the percentage of degradation increased, reaching the level of advanced degradation in both micro-watersheds under study, and when the pH values were close to neutrality, they indicated optimal zones for pasture production. This study provides a new source of information regarding the degradation of high Andean grasslands. It is also the basis for further research in the agricultural sector.

Keywords

• Grassland degradation
• NDVI
• CVP
• Silvopastoral system
• Treeless system
• Floristic composition and spatial distribution