SOME ECOLOGICAL STUDIES ON WILD OATS (AVENA SPP) UNDER SANDY SOIL CONDITIONS

Four field experiments were conducted in newly reclaimed lands at Ismailia Agricultur e Research Station during 2004/05 and 2005/06 winter seasons to compare the growth and seed productivity of wild oats (Avena fatua and Avena sterilis) under various plant distances of wheat or in different placement in barley field. The aim in the first two field experiments, is to study the effect of five plant distances (5, 10, 20, 30 and 40 cm) between wheat and wild oat plant species on seed production for each A. fatua and A. sterilis plants in wheat fields. The aim of the second two field experiments, is to study the effect of four plant - field placements (waste area, field margins, among barley plants and irrigation canal slopes) on growth and seed production of A. fatua and A. sterilis plants in barley fields. The main findings of first experiment in wheat fields results indicated that increasing plant distance from 5 to 40 cm increased growth traits of A. fatua and A. sterilis plants. For A. fatua plants, and A. sterilis plants the plant distance 40 cm increased dry weight of plant, number of total culms/plant, number of fertile spikes/plant, number of spikelets per plant and seed number per plant as compared with the plant narrow space 5 cm in 2004/05 and 2005/06 seasons. In the second experiment plant-field placement significantly affected both vegetative and reproductive characters of A. fatua and A. sterilis plants grown inside barley fields as compared with those out of barley fields. Data of A. fatua and A. sterilis plants revealed that, the plant height was increased significantly with plant placement among barley plants. Dry weight and seed production of wild oat plant species tended to decrease in plants grow inside barley field than those grow in waste place, canal slope or waste field margin. Results suggest to grow wheat on close distances to suppress wild oat growth and its seed production which return to soil. Dense planting can be considered as an element of wild oat management in wheat. The increases in wild oat growth and seed production were achieved with wild oat plants free from barley competition than inside barley fields. Such finding affirmed the importance of out - field wild oat elimination to save guard cereal fields from wild oat seeds contamination.