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Soil Stories with Dr. David Johnson & Hui-Chun Su Johnson
   • SOIL STORIES with Dr. David Johnson & Hui-...   (13:00)

Johnson Su (BEAM) compost was applied to a corn field – see aerial photo. The BEAM only corn was applied at 2 lbs/ac and was $86/ac more profitable with a 2% yield reduction than conventional 100% nitrogen only corn. The BEAM plus 15% nitrogen was applied at at 2 lbs/ac and was $121 more profitable than conventional 100% nitrogen only corn.

Treated corn had fewer small root hairs. Both were in sandy soil. We had to physically pull the clump of soil at the center of the roots to expose them. The control appeared to have slightly less soil aggregation (soil sticking to the roots).

Johnson Su (online) Fungal Count: 23,000 ng/g
Our Johnson Su Fungal Count: 1,400 ng/g

We did not screen out wood chips from our samples and this will skew our results lower – maybe cutting them in half? Still, our Johnson Su had much lower total fungi indicating possibly indicating a lack of fungal foods?

Our Johnson Su (BEAM) compost had about 1,400 ng/g including the wood chips that we mistakenly included in our lab sample. In comparison, BEAM compost sold online has a fungal count of 23,000 ng/g. Given the wood chips in our BEAM compost, we were actually applying at a rate of roughly 1.5 lbs/ac. In addition, our compost had about 1/7th the fungal count. This means we were applying at a rate of 0.2 lbs/ac. Also, the land has been organic for over many years and had a liberal application of compost broadcast over it prior to planting.

Note: The gaps in the corn are due to the planter not working well – didn’t drop a seed. Also, the SE corner is very sandy compared to the rest of the field.

Due to the wet fall weather, the corn may be harvested as snaplage. That combine does not have a meter on it so we may not get bushels/acre numbers. We did take samples wherein every other cob from a 17.5 foot long length of a good row was pulled. We took samples from each of four quadrants – NE, NW, SE, SW. In other words, we took two samples from the control plot and two samples from the 3 lbs/ac plot. The net weight of the cobs from the treated plot was 5% greater than the control. Given the small sample size, this may or may not be significant. Our plan is to make a better Johnson Su compost and increase the concentration for next year along with making sure to have large well-defined plot like in this field.