Think of them as sacks of water with a small amount of flavoring and some vitamins. Because vegetables contain so much water, their yield and quality suffer rapidly when subjected to a drought. Thus, for good yields and high quality, irrigation is essential to the production of most vegetables. If water shortages occur early in the crop's development, maturity may be delayed and yields reduced. If a moisture shortage occurs late in the growing season, quality is often reduced even though total yields may not be affected.
Most vegetables are rather shallow-rooted.
Even short periods of two to three days of moisture stress can damage marketable yields. This often results in a severe stress for that portion of the field that dries out the quickest or receives irrigation last. Another common problem is trying to stretch the acreage that reasonably can be covered by the available equipment. Both of these practices result in all or part of the field being water stressed. It is better to do a good job on some of the acreage rather than a halfway job on all the acreage.