Maize

Maize uses the C4 photosynthetic pathway, which allows it to use water and nitrogen efficiently and sustain high rates of growth under warm, sunny conditions. This physiology, combined with more than a century of breeding, underlies its high yield potential relative to many other cereals.

Maize is grown across an unusually wide range of production systems, from smallholder plots to large mechanized farms, and is used for grain, silage, and, in some regions, fresh consumption as sweet corn. Agronomic practices differ substantially between these systems and by region.

Family

Poaceae (grass family)

Genus and species

Zea mays

Flower structure

Monoecious; male tassel at the plant apex and female ears borne on lower nodes, fertilized by wind-dispersed pollen

Growth habit

Tall, single-stemmed annual grass, typically 1.5–3 m at maturity

Maize was domesticated from wild teosinte in what is now Mexico and subsequently spread throughout the Americas before European contact. Following its introduction to other continents, it became established as a major crop in Africa, Asia, Europe, and beyond.

Maize is now grown on every inhabited continent under an enormous range of climates. Current data on planted area, production, and trade by country are compiled by FAO and national agricultural statistics agencies, and figures should be drawn from those primary sources rather than assumed.

Maize is a warm-season crop that requires a frost-free period long enough for the chosen hybrid to complete its growth cycle. It is sensitive to cold soil and air temperatures at planting and to frost at either end of the season.

Heat and drought stress around silking and the early grain-fill period can substantially affect kernel set and yield. Hybrid maturity class is selected to match the length of the local frost-free season and expected moisture conditions.

Maize performs best on deep, well-drained, medium-textured soils such as loams that combine good moisture-holding capacity with adequate aeration. It is sensitive to compaction and waterlogging, both of which restrict root development.

Establishing a uniform plant stand at the correct depth and spacing is a key determinant of maize yield potential. Hybrid selection, planting date, and target plant population are set according to local climate, soil, and market end use.

• Hybrid selection matched to maturity class, disease pressure, and end use (grain, silage, or sweet corn)
• Crop rotation, often with legumes such as soybean, to manage pests, diseases, and soil nitrogen supply
• Seedbed preparation and planting equipment suited to the tillage system in use
• Weed management during early growth, when maize competes poorly with weeds

Maize has a high nitrogen requirement relative to many other cereals, reflecting its rapid biomass accumulation and yield potential. Phosphorus and potassium support early root development, stalk strength, and grain fill, while requirements for each nutrient depend on soil supply, target yield, and previous cropping history.

Maize is grown both rain-fed and under irrigation, depending on regional rainfall reliability. Water demand peaks around tasseling, silking, and early grain fill, and stress during this window has a disproportionate effect on yield.

Where irrigation is used, scheduling is generally based on estimated crop evapotranspiration and local climate data, with methods and reference values published by FAO and national agricultural agencies.

Maize is affected by a range of fungal diseases, including Fusarium stalk and ear rots, as well as leaf blights and smuts whose importance varies by region and season. Insect pests such as aphids can reduce vigor directly and transmit certain viruses; other regionally important pests include stalk borers and rootworms.

Management typically combines resistant or tolerant hybrids, crop rotation, field monitoring, and, where warranted, locally authorized control measures applied according to their labels.

Grain maize is harvested once kernels have reached physiological maturity and dried to a moisture level suitable for combining and safe storage, with further drying often applied afterward. Silage maize is harvested earlier, at a whole-plant moisture content suited to fermentation and storage as feed.

• Human food, including cornmeal, masa-based products, and sweet corn for direct consumption
• Livestock feed, as grain, silage, or processing by-products
• Industrial starch, sweeteners, and oil extracted from the grain
• Feedstock for ethanol and other biofuel production in some regions