ABSTRACT
Soil organic matter (SOM) is an essential source of plant nutrients, both macro and micronutrients, and a major food source for microbes living in the soil. This chapter reviews the role of SOM in micronutrient availability, plant and human nutrition, detoxification of toxic metals, and, further, its critical roles for biofortification of food crops for human and animal consumption. The less humified SOM with optimum quantity should be applied for increasing bioavailability and crop uptake. The application of fresh organic manure can increase micronutrient bioavailability by forming chelation, and mineralization may release free metals in soil solution. Therefore, the availability and uptake of micronutrients are affected by SOM content. Besides, SOM plays a decisive role in toxic heavy-metal availability by changing soil properties and forming metal chelation and by forming a stable complex.
