A Review of Effect of Nutrient Elements on Crop Quality
The problem of low soil fertility and poor plant nutrition does not only affect crop yields but also crop quality. A review of many refereed published journal articles and books sourced from internet and libraries was conducted with the aim of highlighting the effects of plant nutrition on crop quality. Emphasis was put on elucidating the functions through which various nutrient elements influence biochemical processes and eventually affect the overall quality of various crops and their products. Nutrients reviewed in this paper included elements such as nitrogen (N), phosphorus (P), potassium (K), sulphur (S), magnesium (Mg), calcium (Ca), zinc (Zn), iron (Fe), and cobalt (Co). The crop quality characteristics mostly reported to be affected by plant nutrition include: proteins, carbohydrate, sucrose and fructose content in grains, root crops, tuber crops and fruits; vitamins like beta-carotene content in fruits and tubers; moisture content at storage in cereal grains, potato tuber density; and frying colours, and fruit weight. It has been noted that essential and beneficial nutrient elements contribute to crop quality through functioning as raw materials for the synthesis of various plant components that have food value to humans and animals. Nitrogen and S are raw materials for protein synthesis. Others like Ca, P, Zn and Fe are involved in enzyme synthesis, activation or as electron carriers while Mg, and K are mostly involved in enzyme activation and transportation of materials such as fructose and sucrose from points of synthesis to sites of loading and hence affect quality of fruits, and root and tuber crops greatly. It has been noted that crop quality is also greatly influenced by the synergistic and antagonistic interactions in various nutrients uptake and utilization. Therefore, balanced nutrition is noted to be of paramount importance. From this review it can be concluded that crop quality is a very important area to consider advancing and putting up resources for research since it has a huge bearing on human health and socioeconomic effect on farmers through its influence on marketability of crops and crop products.