STUDIES ON THE BIOLOGY OF WILD OATS. II. GROWTH.

Abstract

Dry matter accumulation by wild oats (Avena fatua L.) in a growth cabinet, after an initial lag period, took place rapidly until 8 wk after emergence. Plant height and the number of leaves per plant increased at a nearly linear rate until 6 wk after emergence. Tillering occurred mainly during the period 2–4 wk after emergence. Low light intensity and short photoperiod severely restricted growth, and delayed heading and maturity. Plants grew best at day–night temperatures of 20–12 C, though initial growth was faster at higher temperature (28–20 C). In a black loam soil, plants responded to added nitrogen and phosphorus only under high light intensity. Both soil moisture and soil pH greatly influenced the growth of wild oats. Greatest dry matter accumulation was attained when soil pH was 7.5 or 8.5 and soil moisture was maintained above 75% field capacity. Hull color of the seed had no effect on the growth of wild oat plants. Plants produced from large seeds had higher dry weights than plants produced from small seeds. Implications of these findings for the control of wild oats are discussed.