**Organic Waste as Fertilizer in Semi-Arid Soils and Restoration in Mine Sites**

Martha Barajas-Aceves

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/62665

#### **Abstract**

The use of organic waste such as tannery sludge which has high organic matter, N and P content, as organic fertilizer is suitable for improving soil fertility in semi-arid soils and for remediation of abandoned mine sites. Retention of heavy metals on fractional processes of organic matter cannot be generalized, it depends on the chemical characterization of organic waste and soil. Addition of tannery sludge containing high concentrations of Cr and carbonates to semi-arid soils resulted in an increase in Cr loss in infiltration and runoff after 6 months of incubation followed by simulated rainfall. Under these characteris‐ tics, results suggest that tannery sludge represents a potential ha ls amended with organic compost. Chemical characteristics of organic waste such as nitrogen content, humified organic matter, pH, EC, CEC, ESP (interchangeable sodium percent), and SAR (sodium absorption ratio) are important properties to consider in organic matter amendment to semi-arid soils participating on the complexity and leaching of heavy metals and nutrients in the matrix of soil.

**Keywords:** tannery sludge, simulated rainfall, mobility of heavy metals, mine tailings, heavy metal fractionation
