Effect of Soil Moisture During Early Stages of Development on Growth and Yield of Cotton Plants1

Abstract

AbstractThe effect of three irrigation treatments on the vegetative development of two cultivars of upland cotton (Gossypium hirsutum L.) was studied in two experiments conducted under different climatic conditions. The treatments differed until the middle of flowering and were designated as L (no irrigation), M (regular), and H (early and excessive irrigation). From mid‐flowering onwards all plots were irrigated regularly.In both experiments, treatment L resulted in a slower growth rate, smaller plants, fewer nodes and fruiting branches, and smaller leaf area index (LAI), and dry matter (DM) weight throughout the season. Small differences were found between the effects of treatments M and H. No excessive vegetative development was observed in this study. The highest rates of DM production were associated with LAI values between 2.0 and 3.0.A close relationship was found between, lint yield, DM production and leaf area duration (LAD). Only small increases in lint yield were associated with LAD and DM exceeding values of 100 days and 600 g/m2, respectively, at the end of the main flowering period. Smaller values of LAD and DM, however, were associated with reduced lint yield. Vegetative development was slower under the high temperatures prevailing in the Bet‐She'an valley than in the Coastal Plain area. Lint yield produced from the first cycle of flowering was lower in Bet‐She'an than in the Coastal Plain, but additional yields were produced in Bet‐She'an from the second cycle of flowering.