ABSTRACT
This chapter describes the information on trace elements, heavy metals and micronutrients found in compost as related to soils, plants, and human nutrition. Trace elements are elements found in minute quantities in the earth's crust. The soil is the major source of trace elements for plants, and it is through food and feed crops that these elements are transferred to animals and humans. Waste applications, fertilizers and other chemicals applied to soils and deposition by water and air add trace elements to the soil. The term heavy metal has become synonymous with an element that is harmful to the environment, plants, animals, and humans. As a result of decomposition, the compost contained higher amounts of humic substances that chelated the heavy metals and reduced it uptake. Cation Exchange Capacity is a measure of the soil's ability to bind cations and release them for availability to plants.
