Total content and bioavailability of micronutrients in livestock manure

MOSCUZZA, CARLOS HERNÁN; RAMOS, M.L; FERNÁNDEZ CIRELLI, ALICIA

REVISTA INTERNACIONAL DE CONTAMINACIóN AMBIENTAL

CENTRO CIENCIAS ATMOSFERA UNAM

Lugar: Ciudad de Mexico; Año: 2020

0188-4999

The use of feedlot cattle manure appears as an important source of certain trace metals in soils that can be mobilized by water modifying the surface and groundwater quality. The current study is focused on assess the bioavailability of copper (Cu), zinc (Zn), cobalt (Co) and molybdenum (Mo) in manure from confined beef cattle systems in different soils of the Chaco-pampean plain, using a sequential extraction scheme. Soils and bovine manure coming from intensive (IS) and extensive (ES) beef cattle systems were collected. Total contents of Cu, Zn, Co and Mo were determined after microwave assisted acid digestion. Bioavailability was evaluated through sequential extraction, including water-soluble and exchangeable fraction (EXCH), organic matter bound fraction (OM), inorganic precipitated fraction (INOR), and residual fraction (RES). Total Cu and Zn contents found in manure coming from IS were higher than the concentration of the aforementioned trace elements determined in all soils and manure analyzed from ES. EXCH-Cu only appears in IS cattle manure samples, while EXCH-Zn found in IS manure samples were higher than the soils samples analyzed. The higher levels of total and bioavailability forms of Cu and Zn determined in IS manure respect to soils samples, require considering when this organic amendment is applied as fertilizer. The reuse of intensive cattle manure as fertilizer in agricultural areas could contribute to reduce the environmental impact caused by the accumulation of excreta in pen soils during long periods in farms.