2008 Beckett, Travis

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2008 Beckett, Travis Powered By Docstoc
					                                Beckett, Travis
         Evaluation of Potato Rotation Management Practices
                 Faculty Mentor: Brian G. Hopkins, Plant and Wildlife Sciences

Introduction

Potato production is an integral part of the agricultural economy of the northwest United States.
Under recent pressure to increase profits, growers have been practicing shorter potato rotations—
leaving a fewer number of years between potato crops in a given field (Myers et al., 2008). This
practice leads to increases in pest and pathogen populations, thus threatening the yield and
quality of future potato crops, and the overall sustainability of the field (Keller, 1989).

This project is part of a larger USDA-funded study, which seeks to improve profitability and
sustainability among Northwest potato growers (Hopkins et al., 2005). The objective of our
project was to quantify the effects of shorter rotations by growing potatoes in a greenhouse
environment, and measuring various factors. Our experimental design included two unique
elements: (1) the soil samples were taken from a wide geographical area; and (2) these soil
samples were from fields with an established rotation history of twelve or more years.

As an undergraduate student, working on my first major research project, I was allowed to make
many important decisions regarding experiment design and implementation. Many difficult
situations arose regarding seed preparation, irrigation methods, and experimental measurements.
Under the mentorship of Dr. Hopkins, I gained valuable experience in effective research methods
as I worked to find solutions to these situations.

Materials and Methods

For this experiment, fifty-four 5-gallon soil samples were gathered from various locations across
the Pacific Northwest. Twenty-seven samples were from short-rotation potato fields, and twenty-
seven were from long-rotation fields. The soils were brought to the greenhouse at BYU, and
Russet Burbank potato plants were planted in each sample. Plant growth, progression, and
senescence (when the plant starts to die back and the potatoes begin to bulk) were monitored
throughout the following months. Four months later, potatoes were harvested and weighed. Soil
samples were also taken for future testing for potato-specific diseases.
Results

The potato plants grown in short rotation soils began senescence an average of 16 days earlier
than those in long rotation soils (Shiffler et al., 2008). In short-rotation soils, the shorter period of
plant growth meant that the potatoes had less energy available for the bulking period.
Accordingly, the potatoes in long rotation soils had significantly higher tuber size, yield, and
number of U.S. No. 1 potatoes (an industry-wide measure of top quality). Further results are
expected once the pest and pathogen tests are completed by the spring of 2009.

Discussion

These preliminary results confirm the hypothesis that short rotations lead to a lower yield and
quality of harvested potatoes. Based on the delay of senescence (16 days), tuber yields in short
rotation fields would be predicted to be 12 Mg ha-1 less than tuber yields in long rotation fields.
An article summarizing these data and results was published in the September 2008 issue of
Potato Grower (Shiffler et al., 2008). In addition, poster presentations were made at the 2008
Utah Conference for Undergraduate Research (UCUR), held at Utah Valley State College, and at
the 2008 Sustainable Agriculture Research and Education National Conference in Kansas City
Missouri. Conference oral presentations planned for 2009 include the next UCUR meeting and
the Western Regional Honors Conference on Preservation, Sustainability, and Renewal.

References

Keller, E.R., (1989). Crop rotation — an important aspect in integrated potato production.
        In: Vos, J., Van Loon, C.D., Bollen, G.J. (Eds.), Effects of Crop Rotation on Potato
        Production in the Temperate Zones. Dordrecht, The Netherlands: Kluwer Academic
        Publishers. pp. 291–301.


Myers, P., McIntosh, C. S., Patterson, P. E., Taylor, R. G., and Hopkins, B. G. (2008). Optimal
      Crop Rotation of Idaho Potatoes. American Journal of Potato Research, 85, 183-197.


Shiffler, A. K., Beckett, T. J., and Hopkins, B. G. (2008). Delayed senescence through rotation.
        Potato Grower, 39(9), 18.


Hopkins, B. G., Alvarez, J., Bauscher, R., Esplin, K., Hafez, S., et al. (2005). Assessment and
      Demonstration of the Sustainability of Long vs. Short Potato Rotations. Retrieved from
      http://www.sare.org/reporting/report_viewer.asp?pn=SW05-067