In-Season Forecasting of Potato Yield to Support Decisions about Application of Fertilizer and Pesticides.

Wageningen University and Research centre collaborates with Agrifirm Group, a cooperative supplier for 17,000 growers /members, to provide data services and science-based recommendations to farmers. The two partners operate a web-based portal (www.akkerweb.nl) which is free to join and on which some services are available for free and other services are fee-based. For potato growers, recommendations are available or under development for sidedress nitrogen application rate, for fungicide application rate to control late blight, and for herbicide application rate for end-of-season haulm killing. For each of these services expected yield is important, either to calculate the required nutrient application rate, or to determine the cost-effectiveness of pesticide application rate. Potato yields in The Netherlands vary widely from year to year, due to the temperate climate. Thus, in-season estimates of yield are required. Here we give an overview of in-season yield estimation using models (regression; simple simulation models; complex simulation models; other approaches). Preliminary results based on production data from commercial farms are given.