When the Hitch family got into hog production 10 years ago, they wanted more options for applying lagoon slurry to cropland. Their goal was to spread slurry over more acreage, at the times and rates they needed.
Curtis Raines, Hitch Farms manager, and employee Cecil Goetz designed and built a system that ties most of the pivots and wells together and takes effluent from the hog lagoons to the pivots.
Hitch Farms' swine effluent system uses 27 hog lagoons, five portable pumping units, 15 booster pumps, 20 center pivots, 30 wells and 50 miles of underground pipe. It allows more cropping flexibility and makes the timing of effluent pumping less critical.
Raines and his crew manage a variable rotation of corn, wheat, sunflowers and silage corn under the pivots, plus dryland production of wheat in the corners outside the pivots' influence.
“We try to put it on the circles closest to the lagoon,” Raines says, “but if something comes up, we can put it wherever we want it.”
The slurry is 40% effluent, 60% fresh water. An environmental specialist conducts effluent and soil analyses on a carefully regulated schedule.
Hog effluent is the only animal waste flowing through this part of the system. Effluent from Hitch's cattle feedlot lagoons flows into another, smaller system.
Five, trailer-mounted, portable pumping units move the effluent. Propane powers the engines. A trailer is parked on the bank of a lagoon and the inlet hose is put into the effluent. Eventually, Raines plans to have a permanent inlet hose at every lagoon to eliminate that step.
A hand-priming device draws fluid into the pump, then the engine is started and the pump activated. Some units have a chopper ahead of the pump. A solid separator puts larger material back into the lagoon through a 2-in. hose.
An in-line meter records gallons per minute (gpm) and acre-feet pumped so operators can record the information for the environmental department's work. A check valve prevents back-flow of freshwater into the lagoon in the unlikely event the engine should shut off.
The pumps have a capacity of 500 gpm but Raines runs them at 200-250 gpm to provide the right amount of flow for the standard mixture of fresh water and effluent to his pivots.
As it leaves the portable pumping unit, the effluent enters the underground system through a portal at each lagoon and is directed to the desired pivot or pivots through the system of pipes, valves and booster pumps.
The 1,000-head finishing houses are mostly grouped in threes, so the effluent from 3,000 hogs goes into each lagoon. Raines says the portable pumps usually stay at each location four to five days.
The underground piping — mostly 8-in. PVC pipe, with some 10-in., and most rated for 50 lbs. of pressure — is the heart of the system. But, three, old, quarter-mile sections with 30-lb. lines are still in the system, so booster pumps are doubly important when water must be moved long distances.
With the area's slope mostly northwest to southeast, that's the general direction of flow for the system. In principle, the system begins with two central lines running from northwest to southeast, with one cross-over point near the high point and many branch lines to pivots and lagoon pumping points along the way (see diagram at right).
For years, Raines has run his pivots at 20-lb. pressures and 500 gpm, but he ischanging nozzles to 700 gpm.
“There were just too many times we couldn't keep up at 500 gpm,” he says. “If we got a little bit behind, or if the transpiration rate was extremely high, especially with corn, we didn't have enough capacity.”
The higher pumping rate will allow application of enough water when irrigation is needed and shut down when it's not. Gypsum blocks are used to monitor soil moisture.
“When the soil profile is full, we shut off the irrigation,” Raines explains.
The 15 booster pumps are indispensable. Some sections of the underground system require low pressure, and friction loss from sending water long distances also can be high.
“My underground water system is really just a reservoir, and I use booster pumps to pick up the water and put it through the pivots,” Raines says. Booster pumps can serve up to eight pivots.
A series of valves at each location allows the water and effluent to be directed where it's needed.
The wells on this portion of Hitch Farms vary from 250-500 gpm. The better-producing wells are on the north and northwest ends, the poorer ones at the southern end, Raines says. All pivots were in place before the swine-finishing units were built. Before hogs, there was some sharing of well water between pivots, but water stayed on the section where it was pumped.
Some states don't allow groundwater to be moved about in this manner. Raines says he's lucky Oklahoma regulations allow it.
The combined piping available for each pivot and the combined use of water for hog and crop production give Hitch Farms options other operations may not have. Raines maximizes water usage through strip-tillage and by limiting irrigation to crop needs. The gypsum blocks used to monitor soil moisture confirm his water conservation efforts.
“My goal is to conserve every drop of water Mother Nature gives me and grow something with it,” Raines says.