EFFECT OF SOWING DATE AND PLANT DENSITY ON BARLEY

Proctor and Maris Puma barleys were sown in October, early March, and late April at 50, 100, 200, 400 and 800 plants per m2and at low and high fertilizer levels. Shoot dry matter and grain dry matter showed no significant response to density for the first two sowings, but increased with increasing density in the last sowing. In all sowings the ear number per m2rose with increasing density, and grain number per ear fell, and there were only small interactions between density and sowing date, but the effect on weight per grain differed markedly in the last sowing from that in the first two sowings. Nitrogen concentration per cent of dry matter in the grain and in the straw showed little response to density and the values for both grain and straw were highest in the last sowing. Nitrogen content per m2for both shoot and grain at first rose, and then fell with increasing density. The maximum amount of nitrogen per m2was found at about 100 plants per m2in the early sowings, and at 400 plants per m2in the last sowing. The nitrogen data indicated a loss of nitrogen from the plant at high densities. Copyright © 1969, Wiley Blackwell. All rights reserved