Thames Valley Potash on Soybean Project

This past year saw the completion of a 3-year trial looking at the value of adding potash to the soybean crop at planting. Although each year had it's own "trials" as to growing conditions, the general results were quite similar. The trials consisted of three different applications of potash.

1. No potash with the seed
2. 110 lbs per acre Broadcast at planting
3. 110 lbs per acre Banded 2 inches to the side and 2 inches below the seed row

Each site contained two replications of the 3 treatments, giving a total number of six plots per farm. In 2002 there were 18 farm co-operators for the project. The yields ranged from a low of 18 bushels/acre to a high of 60 bu/acre and therefore the trials were able to capture the wide variation in rainfall experienced across the 3 county area.

The overall conclusion indicates that there was an advantage to applying potash with soybeans at planting. Broadcasting the potash at planting resulted in 0.3 bushels per acre in increased yield while placing the potash in a 2-inch by 2-inch band beside the seed increased yield by 1.1 bushels per acre.

Averages, of course, do not tell the whole story. Where the soil test was extremely low, (<75 ppm), the response to the 2 x 2 band was significantly higher (± 5 bu/ac). Heavy clay soils under severe drought stress showed significantly higher response. Further analysis is on-going to sort out the full answer.

Intensive Fertilization

This study also included three additional "intensive fertilization" trials in soybeans. These plots contained 23 individual treatments of different fertilizer analysis and various placements of the fertilizer. Results are not available at this time.

I would like to thank all these co-operators very much for their "full" co-operation and helpfulness in conducting this trial over the past three years. It was (and still is!!) a pleasure working with everyone on this project.

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