COMPETITION BETWEEN BARLEY AND WILD OATS AS AFFECTED BY NITROGEN, BARBAN AND TIME OF SEEDING

Abstract

Main effects and interactions of nitrogen, barban (4-chloro-2-butynyl m-chlorocarbanilate) and time of seeding of wild oats (Avena fatua L.) in relation to barley were investigated in factorial growth chamber and field experiments. Culms and yield of barley were increased by nitrogen and barban in both experiments, and increased by each delay in wild oat seeding in the growth chamber only. Culms and yield of wild oats were increased by nitrogen in the growth chamber but not in the field, and were decreased by barban and delayed seeding in both experiments. Competition between the two species growing together is demonstrated by reciprocal relationships between culm numbers and yield of the two species. Similar results were obtained for most main effects and interactions in the two experiments, indicating that competitive and nutrient stresses developed in short term growth chamber studies can be used for the prediction of results under field conditions.