Proposition of critical thresholds for copper and zinc transfer to solution in soils.

Several studies have reported increased copper (Cu) and zinc (Zn) levels in agricultural soils worldwide, mainly due to organic waste and successive leaf fungicide applications in crops. However, the critical transfer thresholds in soils, which can indicate the real risk of environmental contamination and toxicity to plants, remain poorly understood. This study aimed to define the maximum Cu and Zn adsorption capacity (MAC) and threshold (T-Cu and T-Zn) in different soils in Southern Brazil, which present different clay and organic matter (OM) levels.

Development and validation of a siphoning prototype for surface runoff evaluation.

The degradation of soil and water quality encourages research to assess the effects of rainfall on the losses of soil and chemical elements that result from surface runoff. In seasons of high surface runoff, the collectors must support the total volume drained or allow its correct estimation to avoid misinterpretation of the data. The present investigation aimed to develop and validate a compact and low-cost system to quantify surface runoff, sediments, and chemical elements losses using the bucket-siphon sampler system (BS3) siphoning method.

Phosphorus speciation in soils with low to high degree of saturation due to swine slurry application.

Soils with continuous application of swine slurry (SS) may present high phosphorus (P) content and high risk for environmental pollution. The aim of this study was to characterize the forms of phosphorus accumulation in 15 fields with increasing degrees of P saturation (DPS) in a watershed with a high density of swine farming. Soil samples collected from 0 to 10 cm were chemically characterized for water soluble phosphorus (WSP), DPS, Hedley chemical fractionation, and chemical speciation by P K-edge XANES.

Transitions to sustainable management of phosphorus in Brazilian agriculture.

Brazil's large land base is important for global food security but its high dependency on inorganic phosphorus (P) fertilizer for crop production (2.2 Tg rising up to 4.6 Tg in 2050) is not a sustainable use of a critical and price-volatile resource.

Phosphorus availability and microbial immobilization in a Nitisol with the application of mineral and organo-mineral fertilizers.

The aim of this study was to evaluate P availability, P and C contained in the microbial biomass, and enzymatic activity (acid phosphatases and β-glucosidases) in a Nitisol with the application of mineral and organo-mineral fertilizers. The experiment was performed in a protected environment with control over air temperature and soil moisture. The experimental design was organized in a "5 x 4" factorial arrangement with five sources of P and four times of soil incubation.

Environmental vulnerability and phosphorus fractions of areas with pig slurry applied to the soil.

The application of pig slurry as a fertilizer can cause soil and water contamination. Intrinsic characteristics of the environment may enhance this effect and influence the vulnerability of the agricultural system. The goal of this study was to evaluate the accumulation of soil P fractions in areas treated with pig slurry and in forest areas and to propose an evaluation of the areas' vulnerability to P contamination.