Total content and availability of micronutrients in soils and livestock manure Contenido total y disponibilidad de micronutrientes en suelos y excretas bovinas

RAMOS, MARÍA LAURA; MOSCUZZA, CARLOS HERNÁN; FERNÁNDEZ CIRELLI, ALICIA

REVISTA INTERNACIONAL DE CONTAMINACIóN AMBIENTAL

CENTRO CIENCIAS ATMOSFERA UNAM

Año: 2020 vol. 36 p. 115 - 126

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 assessing the availability of copper (Cu), zinc (Zn), cobalt (Co) and molybdenum (Mo) in manure from confined beef cattle systems and 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. Availability 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 availability forms of Cu and Zn determined in IS manure compared to soils samples, require considering when this organic amendment is applied as fertilizer. These results indicate that the reuse of intensive cattle manure as fertilizer in agricultural areas could provide available forms of metals in soils and could contribute to reduce the environmental impact caused by the accumulation of excreta in pen soils during long periods in farms.