Phosphorus Fertilizer & Corn

Corn and Phosphorus

• Phosphorus supplements in the form of fertilizers are most often used to guarantee healthy corn plants and large corn yields. Corn uses phosphorus year-round for the production of stems, leaves and ears of corn. If a soil is lacking in phosphorus, yields and plant growth may be noticeably limited or some plant nutrients may be diverted from ear production to leaf and stem production. When used properly, a phosphorus fertilizer can noticeably increase corn yield, but it can have some unintended consequences as well.

Concerns Over the Use of Phosphorus Fertilizer on Corn Plants

• Possible phosphorus fertilizer runoff into water is a controversy. High levels of phosphorus in water can lead to the growth of algae and aquatic weeds, which can contaminate the water and be very expensive to remove. But according to the University of Minnesota Extension, phosphorus runoff into water is only a problem when phosphorus is improperly used. Phosphorus that finds its way into soil via fertilizers generally will not move once there, and other sources of phosphorus pollution, such as grass clippings and leaf debris, probably account for most phosphorus water contamination.

Management Methods

• If you need to use a phosphorus fertilizer to increase your corn plant yield, properly doing so is important to prevent any unintended consequences. First, test your soil regularly to determine if it actually has a sufficiently serious deficiency of phosphorus to warrant using a fertilizer. If so, follow the application instructions meticulously and never use more than the recommended amounts for your corn plants. If the fertilizer you purchase recommends watering after fertilizer is applied, take care that none of the water runs off into streets, lakes or storm drains.

Other Considerations

• Phosphorus contamination is such a serious problem that some states such as Minnesota regulate the use of phosphorus fertilizer by gardeners and farmers as a matter of state law. The Minnesota law, for example, says you cannot apply phosphorus fertilizers to established turf unless soil testing indicates a serious deficiency. Even though the Minnesota law does not apply to gardens in which you are most likely to grow corn, and even if you live in a state that does not regulate phosphorus fertilizer usage, the laws themselves highlight the importance of using phosphorus fertilizer properly and of the serious consequences of phosphorus contamination.