The results of a "Pond in A Jar" clearly demonstrate the need for retaining nutrients and soil on the landscape rather than allowing runoff into surface waters.
For the demonstration, jars were filled with distilled water and approximately an equal amount of duckweed. They were "treated" and the photo shows the results three weeks after treatment.
In the jar treated with urea, a commonly used nitrogen fertilizer for corn, the roots of the duckweed were burnt off and the water is clear. When the "pond" was treated with DAP, a common fertilizer with an analysis of 18-46-0, the duckweed and algae grew some. Algae is evident with the green tinge to the water.
A very small amount of manure, just a half a teaspoon, has had quite an effect on water clarity. The water is constantly cloudy.
The river water is a little of a surprise, as it is neither green nor scummy. The duckweed is surviving well.
The duckweed in the treatment with two teaspoons of high phosphorus soil at 42 parts per million is flourishing, dark green and has lots of roots in the water. When compared to the treatment with soil with a lower phosphorus concentration of 7ppm, the duckweed is not as green and not as numerous in the lower nutrient-rich water.
- Tonya Gratz is a conservation technician with the Green County Land and Water Conservation Department who shares the results of soil and water-based studies during monthly county conservation committee meetings. She can be reached at tonya.gratz@wi.nacdnet.net.
For the demonstration, jars were filled with distilled water and approximately an equal amount of duckweed. They were "treated" and the photo shows the results three weeks after treatment.
In the jar treated with urea, a commonly used nitrogen fertilizer for corn, the roots of the duckweed were burnt off and the water is clear. When the "pond" was treated with DAP, a common fertilizer with an analysis of 18-46-0, the duckweed and algae grew some. Algae is evident with the green tinge to the water.
A very small amount of manure, just a half a teaspoon, has had quite an effect on water clarity. The water is constantly cloudy.
The river water is a little of a surprise, as it is neither green nor scummy. The duckweed is surviving well.
The duckweed in the treatment with two teaspoons of high phosphorus soil at 42 parts per million is flourishing, dark green and has lots of roots in the water. When compared to the treatment with soil with a lower phosphorus concentration of 7ppm, the duckweed is not as green and not as numerous in the lower nutrient-rich water.
- Tonya Gratz is a conservation technician with the Green County Land and Water Conservation Department who shares the results of soil and water-based studies during monthly county conservation committee meetings. She can be reached at tonya.gratz@wi.nacdnet.net.