Phosphorous Pollution

Phosphorous Pollution

Nutrient Management Water Quality

When I was getting my degree, we were taught that phosphorous does not move.  In the modern world we hear of problems created by phosphorous in our surface waters.  Recent issues in Lake Erie, especially in the Toledo area is teaching us that phosphorous does move.  Very little phosphorous can also cause big problems.  Why is the problem surfacing now.  In many places farmers have been cutting back.  Nutrient stratification could be an issue.  No-Till could be an issue.  Joe Nester, A consultant in Ohio has been looking at rainfall pH as an issue.  He has run some simple tests and found that dissolved phosphorous does increase as rainfall pH approached 6 or a bit higher. Click on the link to learn more about the Great Soluble Phosphorous Mystery.

What I Brought Home from the Nutrient Management and Edge of Field Conference

What I Brought Home from the Nutrient Management and Edge of Field Conference

Water Quality

I looked at notes from Day 3 of the conference and found little new information.  What I brought home was:

• Monitoring runoff and nutrient loading is difficult and expensive.
• We don't always find the answers we think we will.
• A little phosphorous in your water can be a big problem.
• Controlling nutrient releases is not an exact science.
• Conservative use of fertilizer can have a positive impact on water quality.
• Watch out for unintended consequences.
• Guidelines are scarce for farmers or consultants who want to do monitoring in a practical way. 

I was not sure what to think of a presentation by Brittany Hanrahan of Notre Dame University on the first day of the conference.  She set up her study to monitor the effects of cover crops on water quality in a small watershed in Indiana.  She monitored her outflows every 2 weeks.  Her results showed a positive effect from conservation practices applied.  As I listened to all the other presentations I could see that her study was not very sophisticated compared to all the others; yet she got what seemed to be valid results that showed a positive impact.  Somehow we need people like Hanrahan to lead us to a practical side of monitoring so that farmers can set up their own studies to guide decisions.

Reducing Soil Test Phosphorous Levels

Reducing Soil Test Phosphorous Levels

soil fertility Water Quality

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.

Improving water quality with wetlands

Improving water quality with wetlands

Water Quality

As we move toward lowering the nutrient levels in our water, I expect that we will need every tool in the toolbox.  Journal of Soil and Water Conservation published an article in September on using wetlands parallel to a stream.  Researchers were from Wisconsin and found the practice to be effective.  Read about how they used enhanced wetlands for nitrogen removal in an agricultural watershed.   The practice is not a cure-all, but their data suggests that there will be streams where it is appropriate.