Monday, May 18, 2015

LDN Bubblers Maximize Irrigation Efficiency on the High Plains | by Senninger Irrigation

Here at Senninger® Irrigation, we know growers in the High Plains region are concerned about water availability.

Persistent drought conditions in the area are forcing many growers to pump more water from the Ogallala Aquifer, with some depending almost solely on the aquifer to maintain soil-moisture levels. Growers in this windy and semi-arid region also face a greater likelihood of water loss due to evaporation and wind-drift. Our Senninger team knows these conditions make it even more difficult to meet high yield demands and maintain crop quality.

That is why many growers across the region are replacing their sprinklers with our Low Drift Nozzle (LDN) Low Energy Precision Application (LEPA) Bubblers.

Growers already know that not all of the water they pump reaches crop roots. Water is prone to evaporating before it reaches the soil. It can even evaporate directly from the soil surface. Soil is also likely to overheat, crack and lose its ability to effectively channel water down to the crop’s root zone.

LEPA Bubblers help growers get around these issues by applying water around 8 to 18 inches above the soil surface and directly into crop furrows. Keeping water so close to the ground helps avoid wetting crop leaves and reduces the amount of water lost to wind-drift and evaporation. That means nearly all the water pumped is absorbed by the soil.

Research by Leon New and Guy Fipps of Texas A&M shows that spray heads can experience a 17 percent water loss at wind speeds of 15 mph. With LEPA sprinklers, at least 20 percent more water will reach the soil surface compared to conventional spray nozzles. Conventional sprinklers are very susceptible to high wind speed, low relative humidity, temperature and evaporation losses.1

Growers are also discovering that installing LEPA Bubblers on fields where they use strip-till or no-till increases soil moisture and reduces runoff and soil sealing. Crop residue protects the water from evaporation while simultaneously protecting the soil from drying out and overheating.

Others are taking LEPA irrigation a step further and doubling their drops from traditional 60-inch increments to tighter 30-inch spacing between heads to more uniformly soak the soil. The benefits of this closer spacing include less water usage, more uniform root zone coverage during pre-watering, reduced dry spots and high yields despite restricted water supplies.

“Using 30-inch spacing with Bubblers gets the job done with less energy, and nearly all of the water pumped is absorbed by the soil,” says Edwin Smith, High Plains regional sales manager for Senninger Irrigation. “There are certain aspects growers need to be aware of before making a switch to this method, but with the right conditions growers could potentially increase their yields and reduce their costs.”

These ideal conditions include relatively flat land, circle planting and crop residue. The maximum recommended slope for growers considering LEPA or close spacing installations is 1 percent. Planting in circle rows is necessary to increase uniform water disbursement and reduce runoff, while crop residue is needed to increase surface storage capacity and prevent soil redistribution. While just about any type of soil will benefit from close spacing, it is important to consider each soil’s water-holding capacity when setting up close spaced Bubblers. Some soils, like porous sandy soils, can handle much higher application rates than others.

1 LEPA Conversion and Management by Dr. Guy Fipps and Leon New

Reprinted from Valley PivotPoint magazine, Spring 2015