A DYNAMIC-MODEL FOR SIMULATING EDGE EFFECTS IN CARROT CROPS

Benjamin and Sutherland (1992) developed a model to simulate the effec ts of spatial pattern on weight of individual storage roots in carrot crops. Here, a modified version of their model was fitted to their ori ginal data and to a new data set. This modified version explicitly all ows for crop age and makes new assumptions about the relation between storage root and total plant weight. This modified version had fewer a nd less systematic deviations between observed and fitted weights, giv ing approximately 70% of the fitted values within 30% of the observed values. One of the parameters of the revised model relates to availabi lity of resources and is close to independent estimates of the product of daily light integral and the conversion efficiency of radiant ener gy to fresh weight. This might allow the model to be applied readily i n any climatic region where mean daily light integral for the growing season is known.