2,000 pipes

Joel, Marco and Jose are irrigators. Today’s job brings them to a large lettuce field in Arizona. They are taking their morning break, resting in the shadow provided by the tractor and share:

“Today we will connect 2,000 pipes in this lettuce field. It will take us 10 hours to do this. We work in a team of 3. One person drives the tractor, the other two lower the pipes and connect them together. By tomorrow the pump will get connected to this pipe network and water flows.”

Irrigating lettuce fields using pipes involves several methods, each suited to different growing environments and scales. In field production, particularly in the low desert of Arizona, irrigation often begins with impact sprinklers mounted on pipes spaced 40 feet apart, with risers and 4-inch impact sprinkler heads placed at 30-foot intervals.

These sprinklers are crucial during the hot seed germination phase, providing both water and evaporative cooling to prevent seed-bed temperatures from exceeding 140°F.

After stand establishment of the seedlings, the sprinklers are dismantled and often switched to furrow irrigation. Water is delivered through pipes (or ditches) to fill furrows to within 1 to 2 inches of the bed top, avoiding waterlogging that can lead to diseases like bottom rot or leaf drop.

Getting lots of water

Generally, 38 to 50 inches of water per acre are required to produce a desirable lettuce crop, but this varies dramatically with soil type, slope of field, temperatures and planting time window.

Prior to harvest irrigation is cut off. However during harvest, additional irrigation may be necessary between cuttings if multiple harvests are necessary or profitable.

For this field, the irrigation water is delivered via canals from the Colorado River, or from deep wells, in Yuma County.

“We walk the pipes almost every day to check they’re working good and correct any blockages” says Jose.

“One day we’ll install a permanent drip irrigation system for more efficiency. But the boss needs to save up, and perhaps raise prices, to pay for that!” adds Joel.