ON-FARM DEMONSTRATION STUDIES:

Assessing the On-the-Ground Options

For all the uncertainties tied to an Efficiency Conservation Program, one thing is known for sure: Growers will need to rely on a range of methods to generate on-farm savings. But what techniques make sense? Are some approaches better than others?

Recognizing the importance of these questions, the Definite Plan Team (Team) is studying on-farm efficiency conservation practices to discern their effectiveness and replicability.

Specifically, the Team is monitoring approximately twenty on-farm demonstration projects to better understand their water conservation potential. In each case, the team is working with local growers to either study existing practices or demonstrate previously unused approaches.

“There’s a lot of creative stuff already happening down here,” said Jack Keller, who is leading the Team’s work on this effort. “Our task is to work with the growers and assess the water conservation potential of these practices and develop a menu of conservation actions for other growers and landowners to consider.” Below is a brief description of practices being studied.

• Scientific irrigation scheduling

  This study, being conducted on a handful of farms, assesses the improved efficiencies linked to timing and quantifying irrigation applications based on a combination of water data, soil type and moisture sampling, crop physiology and irrigation methods.

• Tailwater reuse systems

  Tailwater reuse systems provide a means for conserving water by reusing the tailwater from row or flat irrigation applications. The Team is studying and evaluating the water savings potential associated with tailwater pumpback systems with and without reservoirs and systems that cascade tailwater from a higher to a lower field. Project Update

• On-farm reservoirs.

  On-farm reservoirs that provide on-farm water delivery flexibility and a supply of water for starting and or completing irrigations and providing small freshening irrigation for vegetable or fruit crops are being studied.

• Enhanced farm delivery service.

  It has been suggested that providing improved delivery consistency, steadiness, and especially flexibility to adjust or shutoff flows may yield considerable on-farm water conservation savings. To test this theory, an automation study is being conducted on the Malva 1 Lateral.

• Irrigation application system studies

  The Team is undertaking several studies to better understand the water conservation potential of irrigation systems that do not produce tailwater. Specifically, the yield and water delivery differences between alfalfa fields using sprinkle, drip, and basin irrigation are being compared to similar fields with more conventional row and flat irrigation. Project Update

• Gated pipe irrigation and different row lengths

  This study is based on a field evaluation using thin-wall, 18-inch diameter gated Poly-Pipe on a carrot field, and computer model studies to compare the water savings potential of differing furrow lengths on various soils.

For each project, the Team will prepare a white paper summarizing the approach and findings. Those findings are discussed below.