Tuesday, March 24, 2015
Reducing Soil Test Phosphorous Levels
Reducing soil test phosphorous levels when levels are high is an issue that relates to high levels of phosphorous in our surface water. I read a study today out of Sweden that looked at phosphorous levels for 7 to 16 years to determine if soil test levels would be reduced if no phosphorous is added. They found that the levels could be reduced, but not as much as removal rates might indicate.That is the good news. The theory is that dissolved phosphorous in runoff would also be reduced. The bad news is that dissolved phosphorous in the drainage water was not reduced. My theory is that it takes time for the phosphorous to move down in the soil, so it will take a lng time to reduce phosphorous in the drainage water. I would say, you should not give up. If your P test is over 100 ppm, you should find some other place to spread manure in order to prevent future problems.