Management strategies enable farmers to maximize forage production

Worland – Forage producers strive to produce as much tonnage each year as possible, but to do that, University of Wyoming Extension’s Carrie Eberle said farmers should focus on using several tools to manage forage production.

“When I think about our goal for forage production, we want to produce the maximum amount of high-quality forage with as little cost and effort possible,” she explained during 2019’s WESTI Ag Days, an event held in Worland on Feb. 12-13. “We also want to maintain production of our perennial forages over the lifespan of the field.” 

A basic understanding of plant biology and soil science is necessary to understanding forage management, and Eberle commented, “We need to be able to evaluate what’s going on with our plants.” 

Plant basics

To grow healthy plants, Eberle said four pieces are required – sunlight, air, soil and water. 

“The sun provides energy to our plants. It provides energy for photosynthesis,” she said. “Air is where plants get their food from. They take CO₂ out of the air and return oxygen.” 

Water helps to transport a variety of things from the root of the plant up the stem and to the leaves, and soil provides structure and nutrients for plants to grow. 

“Soil gives our plants structure and anchors them to the ground,” Eberle noted. “It also provides nutrients. Of the 17 essential nutrients plants need, 14 come from the soil. The other three are carbon, oxygen and hydrogen, which we get from the water and air.”

Nutrients

The most important nutrients for plant growth are carbon, hydrogen and oxygen, which come from the air.

“If we think of the plant as our house, carbon, hydrogen and oxygen are the drywall and lumber. They make up 90 to 95 percent of the structure of the house,” Eberle explained. “But who wants to live in a house made up of just drywall and lumber?”
The remainder of the nutrients provides other necessary pieces for plant growth. Nitrogen, phosphorus and potassium are three other critical nutrients required in larger quantities for plan growth.

“Nitrate, which is nitrate and ammonium in plants, makes up two to four percent of the tonnage in forage crops,” Eberle said. “It forms amino acids and is involved in growth and a variety of plant processes.”

Returning to the house analogy, Eberle likened nitrogen to the plumbing and wiring of the house, making up a large component of the structure of a home or plant. 

“Phosphorus is used to make energy for the plant, and it is critical for photosynthesis,” she said. “While phosphorus doesn’t make up as much bulk, it helps everything happen. Phosphorus is like the light switches and circuit breakers. Without it, none of the wiring and plumbing will work.” 

Finally, potassium provides support, as well – similar to the nails and screws in a house. 

“Potassium doesn’t provide a large percentage of the plant, but it’s important to make sure our plants work properly,” Eberle said. “These nutrients are critical when we think about forages and making sure our plants function properly and are of high quality.”

Managing the system

Eberle noted plants need each of these nutrients every year as they grow, so soils must be replenished to make sure there are adequate nutrients to grow the next crop.

“We need to manage these resources to make sure we can maintain good forage production,” she commented. “We can manage soil, water, sun and, in some respects, air.” 

Water and soil management is more widely understood than sun and air management, said Eberle. 

“We manage sunlight by the number of plants we have per square foot or per acre,” she explained. “More importantly than managing sunlight is managing shade. The closer plants are, the more they compete for sunlight. We want plants close enough together to get a high yield but far enough apart to get adequate sunlight.”

In terms of managing air, Eberle said water can control the plant’s ability to access carbon dioxide. 

“When there’s not enough water, our plants wilt. Then, the pores in their leaves where air exchange happens are not able to open and bring CO₂ into the plant,” she said. “By managing irrigation, we can effectively manage the plant’s ability to bring carbon into their tissues.” 

For non-irrigated fields, Eberle suggested plant spacing as another way to manage water. 

“If we know we’re in a dryland system, fewer plants per acre allows greater access for water,” she said.

Soil

“Soil is the foundation of our plants,” Eberle said. “Understanding our soils will help us to make good, sound management decisions.” 

She continued, “Soil provides 14 essential nutrients for our plants and is the place where plant access water. Having a good foundation of well-managed soil will help maintain productivity in forage fields. 

Soils can be assessed both visually and through laboratory analysis. 

“When we go into our fields, there are certain things we can see that help us determine if there are problems in our soil,” Eberle said, noting that field compaction can be observed, as an example. “But visual characteristics can’t tell us everything.” 

She added, “A number of characteristics require more information.” 

Soil sampling

Soil texture, organic matter, pH, nutrients and cation exchange capacity can all be determined through laboratory tests.

Farmers can take soil samples, largely of the top four inches of soil, and send them in to one of a variety of labs to learn more about the soil they’re planting in.

“Deeper soil samples are important for understanding the total nitrogen bank,” Eberle continued. “Plant roots can access nitrogen at 36 inches in depth, so understanding the nitrogen profile is important.” 

When testing soils, Eberle recommended annual tests that are consistently done at the same time each year.  

She said, “If farmers aren’t doing soil tests, I recommend they start. Producers should also call and talk to who is doing the test to understand more about their results.”

Saige Albert is managing editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.