RELATIONSHIPS AMONG SOIL MOISTURE STRESS, PLANT POPULATIONS, ROW SPACING AND YIELD OF CORN

Abstract

Experiments including variables of soil moisture, plant populations and row spacings were conducted in four consecutive seasons. In two of the years precipitation was inadequate to produce maximum yield of corn.Yield was reduced by soil moisture tension in excess of five bars at a point 40 cm below the soil surface. Substantial yield reduction occurred even where the moisture stress was confined to the period subsequent to tassel emergence. Highest yields were obtained where high soil moisture levels (minimum available soil moisture 25% at 40 cm) were combined with high population (54,362 plants per hectare) and narrow (50 cm) rows. However, interactions among these variables were such that narrow rows increased yield only in the presence of both high population and high soil moisture supply. High plant populations increased yield only where soil moisture levels were high.