Response of Soil and Foliar Application of Zn on the quality and productivity of Maize (Zea mays L.)

Among cereal crops, maize (Zea mays L.)is considered the third most important cultivated grain worldwide owing to its improved adaptability to a wide spectrum of arid and semi-arid conditions (Shahzad et al., 2020). It is a versatile crop that fits well in the existing cropping systems. The huge potential for export has added the demand for maize allover the world. Maize is a miracle crop called as “Queen of Cereals” due to high productiveness, easy to process, low cost than other cereals (Jaliya et al., 2008). Maize grain has raised nutritive worth as it contains about 72% starch, 10% protein, 4.8% oil, 5.8% fiber and 3.0% sugar (Rafiq et al., 2010).

In India, maize is cultivated on roughly 11.2 million hectares, with a record production estimated at 37.25 mt in 2024–25, and an average national yield of about 3.3 t ha-1 (Protect Our Livelihood, 2024). The crop serves multiple purposes: approximately 47% is used as poultry feed, 13% for livestock feed, 13% for direct human consumption, and the remaining 27% for industrial processing and exports.

Zinc is considered the most important micronutrient for normal and healthy plant growth (Tahir et al., 2018). It is a structural component or cofactor of various enzymes involved in many biochemical processes. In plants, it is involved in photosynthesis, carbohydrate metabolism, protein metabolism, pollen formation, auxin metabolism, maintenance of membrane integrity, and induction of tolerance against various stresses (Alloway, 2008). It is also essential for nitrogen metabolism and important for the stability of cytoplasmic ribosome’s, cell division, as co factor to enzymes like dehydrogenase, proteinase and peptidase in the synthesis of tryptophan, a component of some proteins and a compound needed for production of growth hormones (auxin) such as indole acetic acid (Singh and Singh, 1981).

Plant response to Zn deficiency occurs in terms of decrease in membrane integrity, susceptibility to heat stress, decreased synthesis of carbohydrates, cytochromes nucleotide auxin and chlorophyll. Further, Zn-containing enzymes are also inhibited, which include alcohol dehydrogenase, carbonic anhydrase, Cu-Zn-superoxide dismutase, alkaline phosphatase, phospholipase, carboxypeptidase, and RNA polymerase. Depending on the zinc level, zinc deficiency status of plants can be classified as follows: less than 10 mg kg-1 definite zinc deficiency, between 10 and 20 mg kg-1 likely to be zinc deficient, more than 20 mg kg-1 Zn sufficient.