Corn, or maize, is a primary global cereal crop, serving as a staple food and a foundation for livestock feed and industrial products. The simple question of how much corn a single plant can produce does not have a single, fixed answer. A corn plant’s final output is highly variable, determined by a complex interplay between its inherited genetic potential and the conditions of its growing environment. Understanding this variability requires looking closely at the plant’s biology and the agricultural system designed to maximize its yield.
The Direct Answer: Average Yield per Plant
A single, healthy corn plant typically produces one large, fully developed ear of corn in a commercial setting. Modern farming practices aim for a high density of plants, which forces each plant to focus its energy on a single, high-quality ear rather than multiple smaller ones. Under optimal conditions and lower planting densities, some hybrids may develop a second, smaller ear.
The most productive ear usually contains between 400 and 600 harvestable kernels of grain. While a corn ear initiates with the potential for 750 to 1,000 ovules (potential kernels), many at the tip fail to develop fully. Unpollinated or stressed kernels result in what is often called a “nubbin,” which is not counted in the final harvestable yield.
Genetic Factors Determining Potential
The maximum yield a corn plant can achieve is programmed into the seed through genetics. Plant breeders have engineered modern hybrid varieties to perform under the high-stress conditions of dense commercial fields. These hybrids differ significantly from older, open-pollinated varieties, which often developed multiple smaller ears per stalk.
A key genetic trait is the number of kernel rows encircling the cob, which is a fixed number determined early in the plant’s growth. Most commercial hybrids develop between 14 and 18 rows, always in even numbers, though the range can be from 12 to 22 rows. Furthermore, genetic improvements have increased the plant’s “harvest index,” which is the ratio of grain weight to the total plant dry matter, ensuring more of the plant’s energy goes into the kernels.
Environmental and Management Influences on Actual Yield
The genetic potential of a corn plant is only realized if the growing environment provides sufficient resources at the right times. Water availability is a major factor, particularly during the period two weeks before and two weeks after silking (the flowering stage). Drought stress during this four-week window can severely limit the number of kernels that are successfully pollinated, potentially reducing yield by 20% to 50%.
Nutrient supply in the soil also directs the plant’s development and yield. Nitrogen (N), Phosphorus (P), and Potassium (K) are the three major nutrients required for robust growth. Potassium uptake occurs very rapidly early in the plant’s life, and its availability can be restricted if water-stressed soil makes it difficult for roots to access the immobile P and K particles.
Commercial fields often contain between 30,000 and 35,000 plants per acre, creating intense competition for light and nutrients. This high density results in smaller ears and fewer kernels per individual plant compared to a plant grown in isolation. Sunlight is necessary for photosynthesis, and a lack of solar radiation during the grain-fill period reduces the carbohydrates available for kernel development, lowering the final kernel weight.
Scaling Up: Translating Plant Yield to Commercial Farming
In commercial agriculture, the single-plant yield is scaled up to the standard measurement of bushels per acre. A bushel is a volume measurement that, for corn, is standardized to a weight of 56 pounds of shelled grain.
The US national average yield has recently exceeded 180 bushels per acre, achieved by having tens of thousands of plants contribute their single productive ear. The conversion from kernels to bushels is not perfectly uniform; it is generally estimated that 90,000 kernels make up one bushel. However, this number can vary from 70,000 kernels in a year with large, heavy kernels to over 100,000 kernels in a year where environmental stress resulted in smaller, lighter grain.