Assessment and Demonstration of the Sustainability of Long vs. Short Potato Rotations

Project Overview

Project Type: Research and Education
Funds awarded in 2005: $135,756.00
Projected End Date: 12/31/2009
Region: Western
State: Idaho
Principal Investigator:
Amanda Shiffler
University of Idaho

Annual Reports


  • Agronomic: barley, corn, potatoes, sugarbeets, wheat


  • Crop Production: continuous cropping, crop rotation, application rate management
  • Education and Training: extension, focus group, on-farm/ranch research, participatory research, study circle, workshop
  • Farm Business Management: budgets/cost and returns, risk management
  • Pest Management: chemical control, cultural control, disease vectors, economic threshold, integrated pest management, prevention
  • Soil Management: soil microbiology, soil quality/health


    In response to economic pressure, growers tend to reduce years between potato crops, with higher short-term profits but reduced sustainability due to pest pressure. This effect was quantified by comparing potatoes grown in soil with long vs. short rotation history. Short rotations lead to increases in Verticillium dahliae and nematode infections, increase in pesticide costs, and reduction in tuber quality/yield. Therefore,amortized costs of short rotations are likely greater than when potatoes are grown less frequently. A survey of growers shows 59,203+ acres have added at least one year to their rotation length as a direct result of this project.

    Project objectives:

    The objectives of this project were to quantify the effects and educate growers concerning the long-term impacts of short vs. long periods of time between potato crops with regard to potato yield and tuber quality parameters, all major potato pests and pathogens, as well as soil health parameters:

    • nematodes
    • weed seed bank/numbers
    • wireworm
    • herbicide-resistance development
    • bacteria:fungi ratios
    • soil microbial activity
    • Rhizoctonia (Rhizoctonia solani)
    • soil carbon and inorganic nutrient conc.
    • silver scurf (Helminthosporium solani)
    • soil depth, density & aggregate stability
    • white mold (Sclerotinia sclerotiorum)
    • water infiltration rate
    • pink rot (Phytophthora erythroseptica)
    • biomass yield
    • Pythium leak (Pythium species)
    • tuber yield, size, grade, solids, and defects
    • Verticillium wilt (Verticillium dahliae)
    • net economic return
    • powdery scab (Spongospora subterranea subsp.subterranea)
    • cost per rotational acre
    • cost per potato acre and per cwt
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.