Fertility Management in Organic Potato Production

By Derek Lynch, Organic Agriculture Centre of Canada, Truro, NS

The market for certified organic potatoes is growing rapidly and as production expands to meet this demand there will be a need for information on suitable varieties and management options for organic production. To help address these research needs, the OACC is evaluating the yield, blight susceptibility, quality, and consumer preference of potato varieties managed according to certified organic protocols. We are also looking at the effects of different supplemental N inputs on potato yields and specific gravity, plant N uptake, and tuber nitrate levels. Nutrient management studies were conducted on 5 farms in Nova Scotia, New Brunswick and Prince Edward Island. Soil N and moisture dynamics in response to the different N inputs is being monitored during the growing season using standard soil and whole plant tissue sampling techniques, Theta soil moisture probes, and anion/cation exchange Plant Root Simulator (PRS™) probes. Plant root simulator probes were used to monitor nitrogen flux in situ.

At Timber River EcoFarm, yields of the tablestock variety Fabula were as high with the organic inputs as they were with ammonium nitrate. At Kentdale Farms, high total and marketable yields of processing potatoes were achieved with organic inputs. At Brookside, wireworms caused significant losses and obscured trends.

High total and marketable yields of processing varieties are achievable under organic management. Nitrogen supplementation appears to be warranted, based on current premiums for organic potatoes. Variety differences in soil nitrate at harvest may suggest variability in N use efficiency. Good agreement between nitrogen flux measured with PRS™ probes and yield and whole plant N recovery data, suggest PRS™ probes may be an effective tool for predicting soil available N in organic potato production.


Source
1st Canadian Organic Agriculture Research Workshop, University of Guelph, January 2004


Contact Info:
Derek Lynch, Organic Agriculture Centre of Canada, Nova Scotia Agricultural College, P.O. Box 550, Truro, Nova Scotia, B2N 5E3 CANADA
Email: dlynch@nsac.ca

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