Here are links to ISU and K State addressing this subject. I modeled the P Index using Hardin County data from MMPs and found as P rises in soil above 40 ppm, the transport mechanism shifts from soil erosion to dissolved P. When using soil saving practices, no till, cover crops, buffer strips, even wetlands, P loss dropped quickly but th…
Here are links to ISU and K State addressing this subject. I modeled the P Index using Hardin County data from MMPs and found as P rises in soil above 40 ppm, the transport mechanism shifts from soil erosion to dissolved P. When using soil saving practices, no till, cover crops, buffer strips, even wetlands, P loss dropped quickly but then dissolved P rose over the next 10 to 20 years as soil test P rose with continued over application. This is what happened to Lake Erie in the 80s and 90s. Purdue USDA ARS has this well documented. Latest ISU and K State studies in the links below confirm this mechanism of P loss. In my mosel, applying P at the crop removal rate to achieve the optium levels would reduce P loss by 35 to 40 percent. This could be achieved by applying man;ure at the N rate but rotating fields over a 3 to 4 year basi with no P applied in the off years but of course commercial N applied in thos years as well. I hope these links work for you.
Here are links to ISU and K State addressing this subject. I modeled the P Index using Hardin County data from MMPs and found as P rises in soil above 40 ppm, the transport mechanism shifts from soil erosion to dissolved P. When using soil saving practices, no till, cover crops, buffer strips, even wetlands, P loss dropped quickly but then dissolved P rose over the next 10 to 20 years as soil test P rose with continued over application. This is what happened to Lake Erie in the 80s and 90s. Purdue USDA ARS has this well documented. Latest ISU and K State studies in the links below confirm this mechanism of P loss. In my mosel, applying P at the crop removal rate to achieve the optium levels would reduce P loss by 35 to 40 percent. This could be achieved by applying man;ure at the N rate but rotating fields over a 3 to 4 year basi with no P applied in the off years but of course commercial N applied in thos years as well. I hope these links work for you.
https://research.iastate.edu/2022/03/21/iowa-state-scientists-solving-the-complex-puzzle-of-dissolved-phosphorus-loss-from-farmland/
https://www.ksre.k-state.edu/news/stories/2021/08/agronomy-cover-crops-reducing-phosphorus-runoff.html#:~:text=But%20in%20something%20of%20a,loss%20are%20not%20a%20concern.