Friday, June 24, 2011

Water Application | VRI

Sprinkler applicator products used on center pivots are classified into two categories: fixed sprays and rotating sprays. Both types are designed to operate at low pressures to minimize pumping costs. Fixed sprays work best on medium to light soils. Rotating sprays have the largest wetted diameter of all low-pressure sprinklers and work best on heavy type soils or fields with slopes to prevent runoff. Mounting sprinklers below the machine trussing structure is common to reduce water losses due to evaporation and wind drift. Both types of sprays can be used with Valley VRI products.

High water application efficiencies and water distribution uniformity are common place with center pivot sprinkler packages. This allows growers to maximize their crop yields while using less water. To further improve water use, growers are looking to manage their water application based on soil types. A field with soil types varying from sand to clay is a challenge for irrigation management. Apply water based on the sandy type soil and risk over watering the heavy clay soils or apply water based on the clay soils and risk under watering the sandy soils.

The Valley VRI products make it possible to manage each soil type individually. With VRI Speed Control, the machine speed is adjusted to change the water application depth. Using VRI Zone Control, a solenoid actuated hydraulic valve controls sprinkler run time to adjust the application depth. The sprinkler run time is changed by cycling the sprinkler valves on and off. To reduce the sprinkler zone application depth by 50%, the sprinkler valves will cycle the sprinklers so they are running 50% of the time and off 50% of the time.