Farmers have come a long way toward improving irrigation efficiency, says Dana Porter, Texas AgriLife Extension engineer and irrigation specialist at the Lubbock Research and Extension Center.

Farmers may have drilled more wells across the region in recent years, but, along with the higher number of wells has come improved irrigation and management systems.

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“It is true they are drilling a lot more wells in the South Plains,” Porter said. “That’s because—in general—capacity (water-delivery rate) per well is dropping as the aquifer declines. It takes more wells these days to deliver the same amount of water. Some folks are drilling replacement wells hoping for higher delivery rates, as the delivery of older wells drops off for a variety of reasons.”

Others are reworking older systems to make them more efficient. “Many irrigators have had to renozzle center pivots as well capacities have dropped to maintain irrigation uniformity,” she said. “A nozzle package has to match the well's delivery.”

Dividing pivot circles is also common. “Many are irrigating only a portion of their pivots, as they don't have enough water to irrigate the full circles.”

 

Irrigation history

Porter looks back on irrigation history for the area. “In the 1950s, irrigation in the area was developing and increasing.” Most irrigation was through furrow irrigation (row water), and many farmers assumed that system and that much water would be adequate for a long time.

“Apparently they were mistaken. Unless it is well managed with a good layout, furrow irrigation can be very inefficient. Many irrigators (or so I've heard, as it happened before my time) stopped irrigating because water capacities and economics just didn't work anymore.” 

Three decades later technology changed the outlook. “In the 1980s (and continuing) the low pressure center pivots came in, offering greater efficiency and uniformity with relatively low energy costs (compared to high pressure center pivots) and relatively low labor requirements (compared to furrow irrigation),” Porter said.

“Since the 1990s, subsurface drip irrigation has gained ground, as well. Now, some farmers who had stopped using furrow irrigation have put land back into irrigation with center pivots or subsurface drip irrigation. In that time frame, irrigation water use surely increased in some areas.”