Have you ever noticed that sometimes no matter how much water you apply to your field that it only soaks into the top half inch or less. The top thatch acts like a sponge but the water is not getting through to the soil beneath. Ample aeration will assist in keeping this from occurring but once it happens the only thing I know that will assist in alleviating this condition is the use of soil penetrants. These compounds can be applied in the liquid or granular form. They reduce the evaporation of water by allowing the water to penetrate into the soil more readily. There are some that work better in sandy conditions and some better with clay and believe it or not some work on all types of soil. Look into this – you will be glad you did.
As a sidelight – remember that good fertility is a great aid in the best utilization of water by the plant. A good example of this is to observe the green spots that come about where pets urinate on an under fertilized field.