5/1/2018

Pros and Cons of Irrigation Methods

Unorthodox irrigation systems are finding a home in an increasing number of southern rice fields.

Row rice, also known as furrow-irrigated rice, creates three zones in the field — a zone closest to the pipe that is consistently flushed with water, a zone that is intermittently wet and dry, and a zone that remains flooded throughout the season.

The primary benefit is the potential cost savings for fields with a relatively steep grade. No levee construction is required, and more land is back in production.

There are, however, several potential negatives to the system.

  • Three irrigation zones create three yield zones.
  • Weed and disease control is more difficult.
  • Nitrogen management may be compromised.

Another option is intermittent flood, or alternative wetting and drying. “It’s a happy medium between conventional and furrow-irrigated systems,” says Bobby Golden, Mississippi Extension specialist.

A full flood is held for three weeks, while pre-flood nitrogen is incorporated. The water is then allowed to recede in the top paddy. Water management tools then determine when the field needs irrigation.

While water use is decreased, as compared with conventionally irrigated rice, a portion of the field will not maintain a full flood.

On the flip side, a full flood is a great tool to aid in weed control and disease management that may be more difficult in alternate irrigation systems.

Golden says research data thus far shows furrow-irrigated rice and alternative wetting and drying systems use approximately the same amount of water. “There is real potential for improved water savings with the two alternative irrigation systems compared to conventional flooding,” he says. “However, there may be a yield penalty with furrow-irrigated rice.”