Alfalfa tops other hays as water guzzler; helps saline seep fields

April 07, 2012 4:30 pm  • 

Alfalfa and other cover crop type forages are great to use when there are high water table issues such as what happened throughout the region in 2011, said Dave Franzen, soil scientist at NDSU.

Franzen said alfalfa is “the king of water uses.”

In one case, Vernal (public variety) alfalfa was planted and used up more than 30 inches of water and had roots grow to 19 inches in length.

In another case, Russian wild rye forage used 18 inches of water and had roots 10 inches long.

A water table that is too high can cause saline seeps which are white, salty areas that appear on the sides of hills, Franzen said.

Water in fields doesn’t just move downward, he said. Instead, it moves down through the soil until it hits an impermeable layer, then it moves sideways, creating saline seeps.

Producers in high water table areas with saline seeps have been trying to plant something there for many years.

Franzen showed a slide of a producer in Montana who tried planting corn in a saline seep. The corn barely grew at all.

In addition, producers may find their saline seep areas grow over time.

“Depending on rainfall and management, saline seeps can grow over time,” he said.

Alfalfa hay is one of the best crops/forages to plant in the field to manage the seeps, Franzen said.

A study was conducted from 2007-2011 on the Golden Valley County Conservation District farm near Beach, in southwestern North Dakota. In the study, which was conducted on ground with saline seeps and a high water table, alfalfa saline-tolerant varieties from Producer’s Choice Seed were compared for yields with Vernal, the public variety.

Rugged, from Producer’s Choice Seed, had the top average yield over the four years with 11.8 tons/acre. In the last two years, there were two cuttings on every variety.

Second highest producing alfalfa was CW34024 with 11.5 tons/acre, followed by PGI459 and CW064027 at 11.2 tons/acre. All are from Producer’s Choice.

“They are all top hay varieties that producers can use for forage in any situation, but they also have long roots and salt tolerance,” Don Miller, director of product services at Producer’s Choice, said.

Miller said they will be having trials this year of their variety AC Saltlander, which is specific for the most extreme saline areas, while it can be integrated with the alfalfa varieties in the not-so-extreme saline or normal fields.

Rugged, PGI 427, Bullseye, and TS 4002 alfalfa and AC Saltlander have been approved by the National Alfalfa Variety Review board as salt tolerant varieties for 2012.

“We’re getting a lot of calls from producers and selling quite a bit of the Saltlander and alfalfa varieties because of the high water situation last year,” Miller said, addingthat AC Saltlander is usually planted in low-lying areas.

The Northern Plains has several million acres of land that has developed saline seeps, according to Jane Holzer, program director of Montana Salinity Control in Conrad, Mont.

Holzer said she had talked with a producer in Montana that had an 86-acre field, and 46 acres of that field were too wet to plant in 2011.

“The producer had been fallowing part of the land as part of his rotation, instead of planting something like alfalfa,” Miller said.

Franzen said one saline seep field in Montana monitored from 1941 to 1971 grew from 25 acres to nearly 1,000 acres.

“Fallow is not the way to go if a producer wants to manage saline seeps. Fallow increases water storage, but also increases water flow through the seep areas during times of  normal to above normal rainfall,” Franzen said.

While many producers had a “forced fallow” last year due to not being able to get their fields seeded on time with the high precipitation, the best thing to do is to plant cover crops on the land or “at least let the weeds grow,” Franzen said.

Over time, productivity will increase in the saline seep field if managed correctly.

To manage the saline seep fields:

• Use continuous cropping without periods of fallow.

• Grow cover crops as a forage for grazing right after harvest. After taking off wheat, barley, peas, lentils or other early season crops, plant a cover crop above the saline seep to reduce the hydraulic pressure in the soil.

“There is a month where a cover crop with frost resistance can grow and use moisture in the fall,” Franzen said.

The longer the cover crop grows, the more water is used up.

• Grow longer-season crops. In the southwest part of North Dakota, eastern part of Montana, choose corn instead of spring wheat, or  sunflowers instead of field peas.

• Use perennial crops for forage like alfalfa.

“Saline seeps are a growing problem with huge economic and environmental problems if not managed correctly,” said Franzen.