Soil microbial community, enzyme activity, C and N stocks and soil aggregation as affected by land use and soil depth in a tropical climate region of Brazil.

The impact of agricultural land-use on soil microbial community composition and enzyme activity has not been extensively investigated in Ultisols. We investigated soil health parameters by analyzing phospholipid fatty acids (PLFAs), extracellular enzyme activity, C and N stocks, and soil structure. Four land uses were established in a tropical climate region of Brazil: native Cerrado (savanna), monoculture pasture [Urochloa brizantha (Hochst.

Genotypic variation in growth and lead accumulation among accessions.

Selecting (inter-varietal) for tolerance to metal-contamination has been proposed as a strategy to develop superior genotypes for phytoextraction of lead (Pb) through selection and breeding techniques. To understand the differences among accessions of a single species to Pb accumulation, a pot experiment was conducted with three accessions under levels of Pb added to the soil (0, 90, 180, and 540 mg kg). The duration of the growth period was 100 d.

Growth and accumulation of Pb by roots and shoots of L.

In this study, different soil Pb concentrations [24 (control), 80, 136, 362, and 1150 mg kg] were used to analyze the tolerance threshold and accumulation potential of L. in a pot experiment under greenhouse conditions. In addition to growth and Pb accumulation, the following contamination indices were calculated: transfer coefficient (TC), translocation factor (TF), and tolerance index (TI).