THE INFLUENCE OF PLANT-POPULATION SPATIAL ARRANGEMENT ON INDIVIDUAL PLANT-YIELD

Two greenhouse experiments were conducted to evaluate the performance of individual oat (Avena sativa) target plants as influenced by neighb or oat plants with different spatial arrangements. Crop spatial arrang ement was separated into three components: (1) population density, (2) distance between plants (distance dispersion, DD), and (3) angular ar rangement of plants about one another (angular dispersion, AD). Distan ce dispersion was quantified using a weighted mean distance from a tar get individual to its neighbors. Angular dispersion of neighbors aroun d the target was quantified using a measure of circular variance. DD a nd AD were combined to create a dispersion index (DI). At constant den sity, distance dispersion treatments were combined with angular disper sion treatments in a randomized-block factorial design. Target plant b iomass production was predicted using a rectangular hyperbola equation including population density, DD, AD, and DI as independent variables . Fifty-five and 44% of the residual variation (the variation not acco unted for by density alone) in individual plant yield was accounted fo r when spatial arrangement (DI) was added to the regression. The appro ach can be used to compare the intensity of competition among differen t crop planting patterns.