**3. The role of secondary metabolites in enhancing agricultural productivity**

The resistance against herbivores and pathogens is a role played decisively by the chemical protection nature of plants**,** the secondary metabolites; they are plant features important especially for protection against a wide range of microorganisms such as bacteria, viruses, fungi, arthropods, herbivores, and vertebrates [88]. Soil decomposition is influenced by plant secondary metabolites by increasing nitrogen immobilization in the soil; cycling of carbon (C) and nitrogen (N) is affected by terpenes and tannins [89].

Exudates from plants roots contain secondary metabolites that can attract, kill, or deter underground microbes, herbivorous insects, and nematodes, competing plants and underground injuries are also inhibited [90]. Plants secondary metabolites contain potential toxic substances used for defense against insects; these chemical compounds can be utilized for design of future insecticides with multiple or specific targets [91]. A good example of an insecticidal compound of such nature is pyrethrin derived from the flowers of Pyrethrum cinerariaefolium plant; pyrethroids are the synthetic analogs of pyrethrin [92].

In terms of animals' productivity, animals that ingest forages containing different plants secondary metabolites get their meat and dairy products enhanced in terms of biochemical richness making them good for human consumption [93].

In today's food industries, plants secondary metabolites are used extensively as flavoring, coloring, and texturizing agents. Preservation and anti-browning are done with metabolites possessing antioxidative properties [94].
