Agro-ecological zoning at the regional level: spatio-temporal variation in potential yield of the potato crop in the Argentinian patagonia

The purposes of this study on potatoes were to perform an agro-ecological characterization, to estimate the potential yield of the crop with the LINTUL-POTATO simulation model, and to identify yield determining, yield limiting and yield reducing factors for the patagonic area of the Rı́o Negro valley (Argentina), where the potato crop acreage is rapidly expanding. The valley was divided into three areas based on differences in climate: high, medium and low valley, represented by the weather stations Cipolletti (SL 38° 57′, WL 67° 59′), Choele Choel (SL 39° 17′, WL 65° 39′) and Viedma (SL 40° 47′, WL 62° 59′), respectively. Suitable soils for potato cultivation were identified at the great group soil level: torrifluvents, torriorthents and haplargids. Potential yield of the crop proved similar to that obtained in other regions of the world (>25 tonne ha −1 dry matter) and because of high irradiance and ample thermal amplitude, dry matter content of the tubers can be higher than that obtained in other potato growing areas of Argentina. In late plantings, high temperature is the most important yield defining factor because of its negative effect on dry matter partitioning. Inadequate soil tillage after land reclamation, low soil fertility and persistently strong winds were identified as the most important yield limiting factors, whereas yield reducing factors are not yet in evidence in these new areas.