Crop Water Management to Optimize Growth and Yield

Abstract

Due to the strong year-to-year variability in water supply and demand in most cotton growing regions, plant managers must be able to adapt their management (especially irrigation, fertilization, growth regulation, and pest management) to each year’s climate and plant conditions. Only with a solid understanding of optimal plant-water relations at different growth stages and the ability to prioritize and assess risk can an optimal water-management program be developed.

The cotton plant undergoes a series of stages during its development from dormant seed to the production of mature bolls. While some of these stages are distinct and abrupt, others are gradual and overlap. Thus any consideration of the optimal plant-water relations for a specific time is complicated by the presence on the plant of organs and tissues in different stages of growth. For example, during long effective- bloom cycles (six weeks or more) a plant may contain both opening bolls and young bolls with economic value. However, the optimal plant-water relations for young bolls is substantially wetter than for opening bolls. Thus the optimal plant-water relations for the entire plant during early boll opening must incorporate the relative contributions of different fruit stages to economic value, where economic value includes such factors as yield, quality, risk, and additional input costs. Having said this, the most important factor to consider when designing optimal plant-water relations is the impact of water management decisions on the ability of the plant to initiate, retain, and mature harvestable bolls.