Vol. 7, Issue 4, Part D (2021)

Abstract
Zinc (Zn) is a structural constituent and regulatory co-factor in enzymes and proteins involved in many biochemical pathways. Many agricultural soils cannot meet the Zn requirements of crop plants, making Zn deficiency a common nutritional problem worldwide, particularly in low organic matter, highly limed, light-textured, salt resistant, and waterlogged soils. Hence, the Zn uptake and transport in plants and its consumption by humans and animals are considerably affected. Humans are more vulnerable to Zn scarcity because it controls the hormonal receptor sites, biologic membranes and plays a role in DNA and RNA metabolism. It participates in signaling, gene expression, and apoptosis. Hence, the scarcity of Zn in soil disrupts the whole food chain. Therefore, Zn shortage is a major agricultural and human health problem around the world. Compositing, bioslurry, and farmyard manure application could be a suitable option to remove all the above issues because they affect soil composition, and improve the soil properties in a more sustainable manner. Furthermore, they can increase the organic matter contents in soil and enhance the Zn concentration in grains, when applied with inorganic Zn fertilizers. The present review discusses the organic sources beneficial effects on various crops.