Follow these recommendations to reduce phosphorus loss from your farm:

• Apply phosphorus to fields that have an agronomic need for phosphorus. Phosphorus applied to low-testing fields will increase yields. Better plant productivity may lead to less erosion and runoff.

• Use the phosphorus index to identify fields that have a high potential for phosphorus loss.

• Use crop selection and soil conservation practices to reduce the amount of runoff and erosion from agricultural fields.

• Maintain buffer strips around water resources. Setback areas filter out soluble phosphorus and eroded soil particles before they reach streams or lakes.

• Apply phosphorus sources below the surface in tilled systems. This helps only if phosphorus incorporation does not significantly increase erosion.

• Surface-apply phosphorus sources during periods of the year when runoff is unlikely. Runoff is most likely to occur in spring when soils are often saturated with water and rainfall events are most frequent.

• Do not surface-apply phosphorus sources to frozen, snow-covered, or saturated soils. Applying manure under these conditions is not recommended and is illegal under water quality regulations in some states.

John A. Lory
Associate Professor of Extension
University of Missouri