Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.

The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep).

Long-term effects of crop management on Rhizobium leguminosarum biovar viciae populations.

Little is known about factors that affect the indigenous populations of rhizobia in soils. We compared the abundance, diversity and genetic structure of Rhizobium leguminosarum biovar viciae populations in soils under different crop managements, i.e.