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Dairy lagoon water through SDI works at DeJager Farms

Todd Fitchette Nate Ray DeJager Farms
Nate Ray, general manager of DeJager Farms, says alfalfa yields across 8,500 acres of the forage crop average above nine tons, with stands on subsurface drip pushing over 10 tons per acre.
DeJager Farms finds success in running dairy lagoon water through subsurface drip system; plans to add it to alfalfa fields later this year

Nate Ray says 4-6 years is a good target to hit in the life of his San Joaquin Valley alfalfa stands. Good stands will go six years. Ray now has one stand in its eighth year.

Not all of his alfalfa fields have survived that long. Later this year, he will pull some stands in production for four years, re-planting in a corn and wheat rotation.

Alfalfa is important to Ray, general manager of DeJager Farms, a dairy and farming operation near Chowchilla, Calif. that spans two counties. It takes lots of alfalfa to feed 25,000 cows across eight dairies.

DeJager Farms grows much of its forage needs, which includes about 8,500 acres of alfalfa. Ray also grows silage corn and wheat in rotation that typically lasts about three years before returning to alfalfa.

About 1,000 acres of alfalfa currently sits atop subsurface drip (SDI) tape buried 12-14 inches under the surface. As he transitions corn and wheat fields to alfalfa Ray will do something perhaps no other alfalfa grower in the state is doing.

For several years now, Ray has irrigated his strip-till corn and wheat through irrigation lines – some buried, some on the surface – with a combination of fresh water and dairy lagoon water. While the use of dairy lagoon water is nothing new for dairymen, running it through SDI is basically unheard of because of the solids in the water and the tiny openings in drip irrigation systems.

Ray says there is nothing too special about delivering the lagoon water through drip tape.

“It’s simply a matter of your filtration system,” Ray says.

Running dairy lagoon water through the Netafim drip tape requires double the filtration capacity of a normal drip irrigation system, he says. Additional sand separators added before the filters help take as much load off the filters as possible, allowing the manure water to flow through the small openings.

Beyond that Ray uses a computer controller that measures the total dissolved solids in his irrigation water through its electrical conductivity (EC).

Ray established baselines from lagoon water samples that let him “dial in” the EC to his computer controllers. From there, the controllers regulate water coming in from fresh lines and those from the dairy lagoon, allowing him to apply the correct amount of nitrogen to his crop via the SDI system.

There are several benefits to this.

1 - Running drip irrigation under his alfalfa reduces water use by 25-30 percent. He’s also seen a 20-25 percent bump in tonnage compared to fields of the same age and variety that are flood irrigated.

2 - The use of dairy lagoon water also saves fertilizer costs. Ray has effectively cut his need for commercial phosphorus to zero.

He is still curious to see if SDI can boost hay quality, which he currently says has not generally been affected either way when compared to flood-irrigated alfalfa.

Ray primarily plants two alfalfa varieties – Dairyland and W-L alfalfas in dormancies that range from four to eight. About 70 percent of his fields are in dormant varieties that range from four to six, with the balance in eight dormancy varieties to manage hay quality for the dairies while managing for higher yields.

Late fall he planted the first field of the low lignin variety Alforex Hi-Gest 660. It's too early to know how this will perform.

His alfalfa is all conventional.

New plantings

Ray says new alfalfa stands are planted in the fall. After preparing the ground that for the previous three years has been in a corn and wheat rotation he uses sprinkler pipes to pre-irrigate the soil. After planting the crop he irrigates with sprinklers again to germinate the seeds before turning on the SDI and removing the sprinklers.

“We’ll spend a little extra money up front to make sure our seed beds are in the right location,” he said. “A firm, compact seed bed is probably the most important thing in planting alfalfa.”

Rodent control can be an issue for SDI systems. Yet outside of a 35-acre field where Ray says the rodents are a considerable challenge he’s been fortunate.

“We’ve probably been one of the luckiest if not the luckiest around when it comes to rodents,” he says.

Part of his good fortune has been site selection – choosing fields without uncontrolled habitat nearby.

Aside from luck, Ray works hard to physically trap rodents prior to planting. He stays focused on trapping early on to reduce numbers.

“We’re relentless on keeping them out before they get in, and that’s probably been the key.

From his first cutting in late March through mid-June this year, the first few months of the growing season was relatively cool, allowing Ray to produce dairy-quality hay through late June. Later, high temperatures in the San Joaquin Valley rose 30-40 degrees within a week, bringing new challenges ranging from water needs for the crop to insect pressures from beet armyworms and the western yellow stripe armyworm.

As August rolled around Ray also saw aphids.

Benefits of SDI

Improved weed control is another benefit of SDI if water is kept at the root zone and not allowed to percolate to the surface, he says.

SDI allows growers to maintain consistent soil moisture at the root zone that aids in canopy growth.

With the SDI, irrigation is generally turned off several days before cutting to stress the plant a little and allow the soil to dry before harvest begins.

Hay cut on day-one has SDI turned back on for about two hours per day on days two, three and four, depending on the soil type. The idea is to get water to the stressed plants without pushing irrigation water to the surface where the hay is drying.

Once his alfalfa is baled and out of the field, he increases the duration of his irrigation sets to catch up on the water plants need before cutting back slightly to maintain water needs in the crop. The goal is to quicken plant growth, which he believes helps further stunt possible weeds by quickly increasing the plant canopy.

The first alfalfa cutting is in late March to early April. Timing the first cut is entirely based on weather and plant growth. The initial cutting is typically green chopped and bagged at dairies.

Second and third cutting hay – generally the higher quality milk cow alfalfa, is cut on a 31- to-32-day cycle with the goal of pushing the second cutting out as long as possible to make more yield.

After the third cutting, the cutting cycles is shortened to 26-27 days. By this time high, temperatures in the San Joaquin Valley are too warm to produce the higher-quality milk cow hay, leading Ray to focus primarily on tonnage.

Alfalfa yields across the entire farm generally average nine tons per acre though some stands can produce 12-13 tons. He typically has seven to eight cuttings a year, generally alternating where two years in a row he cuts seven times, then cuts eight the next year, rotating back and forth through the life of the stands.

Ray will discuss his alfalfa operation using SDI during a presentation at the 2017 Western Alfalfa & Forage Symposium, Nov. 28-30 at the Grand Sierra Resort, in Reno, Nev.

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