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How does surface irrigation work for grain and forage crops?

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A green cotton combine harvests a field of mature cotton plants, with white cotton bolls visible across the landscape. — Agricultural technology Cotton combine harvesting a cotton field.

Surface irrigation is a method of irrigation where water is distributed directly over the soil surface. For this method to be effective, the land must be graded to ensure uniform slopes.123

For grain and forage crops, the flood system is the most common surface irrigation technique. In this process, water is applied at the edge of a field and allowed to flow across the entire surface to the opposite side.2

Regardless of the specific surface method used, systems often include waste-water ditches at the lower edge of the field. These ditches serve two critical purposes: they allow for the removal of excess water for use elsewhere and help prevent waterlogging, which is essential for maintaining healthy crop production. While furrow irrigation is also a form of surface irrigation, it is typically reserved for row crops like corn or potatoes rather than grain and forage.2