Enhancing Potato Production by Improving the Soil Food Web

		Project Leader: Robert Jones, Jones Farm, Hooper, CO Technical Advisors: Merlin Dillon, Area Extension Agent, Center, CO Jon Gilley, Agro Engineering, Alamosa, CO Project Year: 2004, 2005

Project Summary

The problem addressed in this project is the limited nutrient cycling in the soil when using pesticides and conventional fertilizers, particularly for potato growth. The nutrients being focused on in this study are nitrogen and phosphate.

The research took place on a center pivot circle 120 acre field of potatoes planted in two 60 acre sections. Half of the field was planted with the variety Norkotah and half planted with Yukon Gold. The treatments compared were a conventional fertility program and an alternative program using aerobically generated compost, actively aerated compost tea and fish hydrolysate as the nitrogen source. The conventional pre-plant for potatoes used a liquid fertilizer applied in a band during the planting process with an additional 70-80 pounds of nitrogen injected through the sprinkler during the growing season. For the alternative system, three tons of compost were applied per acre with five gallons per acre of fish hydrolysate. The intent was to apply equal amounts of nitrogen for all treatments. Compost tea was used instead of fungicides. There were two pre-plant treatments (one conventional, one alternative) replicated three times on each of the 60 acre halves. An additional treatment was a split of the circle to compare two different top-dress treatments (conventional and alternative). The conventional top-dress treatment was liquid urea plus thiosol compared to fish hydrolysate.

The results learned from this research show that despite the fact that a delayed shipment of fish hydrolysate that delayed the application of nitrogen for a month, the yields show that the compost/fertilizer was 512 cwt. compared to the regular fertilizer which produced 572 cwt. All of the results gathered reinforce the case for compost as a possible alternative for traditional fertilizer pre-plant blends. The fish was not effective in maintaining nitrogen as a top-dress, but results may have been different if it were applied at the proper time. Despite the fact that there were unforeseen obstacles in this research, other growers should learn from this that it is possible to move towards more sustainable practices without losing much profit.

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