Soil Test Phosphorus Reduced in SWCD Program

06/02/2021

News Release from Mercer Soil and Water Conservation District:

Mercer Soil and Water Conservation District (SWCD) was awarded an Ohio EPA 319 grant in 2018 to install multiple best management practices in the Beaver Creek HUC-12 (Grand Lake St. Marys) watershed.  Mercer SWCD offered cost-share to farmers to enroll fields in a double-cropping program within the Beaver Creek HUC-12 watershed.   This was a two-year program where farmers harvested two crops each year from the same acreage.  Additionally, no manure or commercial phosphorus was applied to the field during those two years.  As a general practice, we saw wheat planted in the fall followed with harvest of the wheat as a forage crop during the following spring.  The wheat forage harvest was then followed by planting and harvest a traditional crop of either corn or soybeans.  Other options were available, but this was the most common double cropping method used during this trial.

It was determined that this practice dropped the soil test phosphorus (STP) value an average of 11 ppm  across the fields using the Bray P1 extraction method over the two years.  This drop in STP is approximately double what is typically seen with harvesting only one crop per year from the same acreage.  Any field with a STP value above 92 ppm Bray P1 would be a good candidate for the double cropping practice to promote the reduction of STP in that field.  According to The Ohio State University’s College of Food, Agricultural, and Environmental Sciences, soil phosphorus levels are strongly related to the concentration of phosphorus in runoff water and less phosphorus in the soil should result in reduced phosphorus runoff risk. (https://oardc.osu.edu/sites/oardc/files/imce/files/OARDC_impacts/WaterQuality.pdf)

Please contact Mercer SWCD at 419-586-3289 ext. 3 for more information.