Efectos de biochar y compost en un suelo de huerto urbano moderadamente contaminado por metales pesados

Abstract

[EN]: Wood biochar (B) and sewage sludge compost (CS) were added, both separately or together, into a moderately polluted urban farm soil (Cu 197 mg kg-1, Pb 295 mg kg-1, Zn 182 mg kg-1). Amendment doses were 1% (treatments B1, CS1, and B1CS1 combining both products) and 2% (treatments B2 and CS2). Lettuce plants were grown in 2 L pots (3 replications per treatment) and plant biomass and composition, enzymatic activities, and available soil metals were determined. All the amendment treatments increased aerial and total lettuce fresh weight (plant fresh weight: Control≤B1≤B2≤B1CS1<CS1≤CS2) in spite of a reduction in root weight. In general, amendments slightly reduced the phosphatase, glucosidase, dehydrogenase and urease activities but their decrease was significant only for the effect of B1CS1 in the (sum of) four activities and for B1 and B2 in dehydrogenase activity. EDTA extractable-trace metals and -nutrients were reduced by B and CS, although these reductions were only significant in the case of treatment B1CS1 for which 11 to 21% depletion in relation to the control was achieved. These results suggest a synergistic action in the case that B and CS are jointly added. However, the lettuce metal contents did not reflect the decreases observed in the EDTA extractable-metal contents.

[ES]: En un suelo de un huerto urbano, moderadamente contaminado (Cu 197 mg kg-1, Pb 295 mg kg-1, Zn 182 mg kg-1) se han usado un biochar de madera /B) y un compost de lodos (CS). Las dosis utilizadas fueron 1% (tratamientos B1 y CS1 con cada producto y B1CS1 con la mezcla de ambos) y 2% (sólo B2 y CS2). Estas mezclas se usaron en macetas de 2L (3 repeticiones) cultivando una lechuga por maceta, y determinando la biomasa, los contenidos de metales disponibles en suelo y las actividades fosfatasa, glucosidasa, deshidrogenasa y ureasa. Todos los tratamientos con enmiendas aumetaron la biomasa aérea y total treatments (peso fresco: C(Control)≤B1≤B2≤B1CS1<CS1≤CS2) a pesar de una reducción de la biomasa radicular. En general, las enmiendas disminuyeron ligeramente las actividades enzimáticas aunque sólo significativamente en el caso de B1CS1 sobre la suma de las 4 actividades, y B1 y B2 sobre deshidrogenasa. La concentración de metales extraídos en AEDT disminuyó con B y S aunque sólo B1CS1, con reducciones entre 11 y 21% respecto a C, actuó significativamente. Estos resultados sugieren una acción sinérgica de la mezcla de B y CS respecto a las propiedades consideradas. 1 lnea en blanco, espaciado simple