Chemical and granulometric characterization of soil and its influence on the bromatologic composition of pastures in savannah region, Central Brazil

Livestock is responsible for much of the world's land use, and grazing areas are the main livelihood of the world's largest commercial herd. Most of the pasture areas have low productivity because they are at some level of degradation. This study aimed to apply multivariate analysis and remote sensing techniques for to evaluate the influence of soil granulometric chemical characteristics and bromatologic composition associated with vegetative index classes of pastures cultivated in the Savana biome, region of Central Brazil. The pasture areas were selected according to Normalized Difference Vegetation Index (NDVI) considering the annual average and their classification into a low vegetative index (LVI), medium vegetative index (MVI), and high vegetative index (HVI) levels. Forage material collections were carried out on six dates (bimonthly) and a soil collection date. Productive parameters of the pasture were evaluated: fresh mass (FM), dry mass (DM) and tillers (TILL); pasture bromatologicals: crude protein (CP), total dry matter (TDM), dry matter, ether extract (EE), neutral detergent fiber (NDF) and acid detergent fiber (ADF), and non-woven fabric (NW); the chemical composition of the soil: pH, Ca, Mg, Al, total acidity, P, K, cation exchange capacity (CEC), organic matter (OM), base saturation; and soil granulometric: clay, silt, and sand contents. The results were submitted to descriptive statistical analysis and discriminant analysis by partial least squares (PLS-DA). The PLS-DA analysis method allowed us to differentiate pasture areas in terms of vegetative indices (HVI and LVI) through the chemical and granulometric parameters of the soil and by the productive and bromatological parameters of the pastures. The granulometric characteristics of the soils were the parameters with the lowest weight to differentiate the pastures in terms of low, medium, and high vegetative indexes. Pastures with high vegetative index (HVI), even in intensive systems, showed better chemical quality (Mg, P, K, OM, CEC, and Ca) of soils and bromatological quality of forages (FM, ADF, PB, and TDM). •The PLS-DA analysis allows separating pasture areas in terms of vegetative vigor.•Forage quality and production is influenced by soil chemical parameters.•Pastures with high vegetative vigor have better bromatological quality.•Satellite data allows characterizing pasture areas in terms of vegetative vigor.