Phosphorus

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Research conducted by Isaac Mertz, Iowa State University, photo by Ben Pease, Iowa State University. Ben tweeted this photo illustrating the response of bentgrass to application of 0.5 lbs P/1000 sq ft (2.4 lbs 12-48-5/1000 sq ft) spray applied. The response is dramatic. Even though we would expect to see an increase in soil P of about 15 ppm, no increase in soil P was detected. In Ames, IA, bentgrass GP suggests that 0.07 lbs P/1000 sq ft per month (2 ppm) is needed during the summer. Not much P is needed to maintain healthy bentgrass and the MLSN guideline of 21 ppm M3 P is generous - possibly too generous.

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Cultural Practices