Effective management tools + good varieties + other factors = increased opportunity for profitability in crop production.

This equation is a constant goal of wheat producers in California and Arizona who utilize an alphabet of tools from A to Z to achieve a high-quality crop and profitability while serving as good stewards of the land.

Four University of California specialists armed with the latest wheat production recommendations spoke during a wheat session at the California Alfalfa and Grains Symposium in Sacramento, Calif., in December.

Lee Jackson, Kent Brittan, Steve Wright, and Steve Orloff shared knowledge from their combined 100 years of service to California’s agricultural industry.

Jackson, UC Cooperative Extension specialist emeritus, Davis, called variety selection possibly the most important decision a grower can make to achieve a high quality, high yield wheat crop. His advice included growing multiple wheat varieties; not just one.

“Growers should not rely on a single variety,” Jackson said. “It’s best to spread out production risks by growing several varieties with resistance to prevalent diseases and different traits which fit the particular growing region.”

A willingness to change varieties each year is important since races of pathogens can overcome previously-resistant varieties.

On variety selection, Jackson said, “Decisions should be based on cultural practices in growers’ cropping systems, the needs of available markets, and first and foremost the quality and yield traits which allow the grower to make a profit.”

Variety selections should be based on yields over a period of years under different production conditions.

Variety traits should be carefully weighed by growers. Yield is the top factor, but also consider variety plant growth and development characteristics including plant stature, and the intended use of the variety (green chop, grain, etc.).

California is actually a wheat-deficit state where more demand exists than supply, according to the California Wheat Commission. About 60 percent of California-grown wheat is consumed by people. The balance is fed to livestock as silage, green chop, forage, and hay.

Another factor to consider is the disease and pest reaction of different varieties. Reactions can change from year to year.

“Always be on guard against new and emerging diseases,” Jackson said. “Be flexible and open to the use of new varieties,” Jackson said.

Recently retired UCCE farm advisor Emeritus Kent Brittan, Yolo and Solano counties, shared his views on wheat stand establishment. Brittan says site selection is usually not high on the grower’s priority list, but should be.

“Site selection can make or break a small grains planting,” Brittan said. “Rainfall drainage should be the number one consideration.”

Many small grain plants cannot live beyond 2-4 days submersion in water. In heavier soils, Brittan recommends planting wheat on beds.

Seedbed preparation strategies vary across different growing regions based on crop rotation, soil type, soil and moisture conservation, residue management, and the grower’s approach to tillage.

“The main objective is to produce a firm, debris- and weed-free seedbed for rapid germination and emergence,” Brittan explained. “Good seed-soil contact is important for quick imbibitions and germination.”

He says base tillage decisions – conventional or no-till – on existing plant residue, the planting method, soil type, and other factors. Avoid working wet ground.

“The decision to flat plant or plant on beds depends on the soil. Drill the seed and avoid broadcast planting unless time and weather are a threat.”

Most California wheat is drill planted versus aerial application.

“It’s almost always better to drill,” Brittan said. “Drill planting creates a more uniform seed depth, lower seeding rates, better soil contact, fertilizer placement, and improved emergence.”

Brittan says calibrate planting equipment when changing seed varieties since the seed size often varieties between varieties.

Weed challenges

Steve Wright, UCCE farm advisor in Tulare and Kings counties, discussed weed challenges in wheat. Wright said wheat fields almost always require herbicide treatment.

Weeds are controlled at a minimal cost with herbicides and assist with an overall weed management plan in rotation with other crops. Care must be taken with neighboring crops at the time of application.

Herbicides replace tillage since tillage is not possible during the growing season. Crop rotation is critical for broadleaf and grassy weed control.

Wright shared his latest herbicide trial findings.

“One of the most effective herbicides for broadleaf weed control is Express plus MCPA which is less injurious to grains and has a wider window of application,” Wright said.

Many herbicides on the market, when used as a tank combination, usually provide the most effective weed control in wheat since most fields have different weed spectrums.

Among those include MCPA which Wright says can be applied as early as the 4th or 5th leaf stage at tiller initiation. The herbicide 2,4-D is best applied when the plant is well tillered.

The contact herbicide Buctril works well as a tank mix with Puma and other products. Puma and Osprey require separate applications for broadleaf and grass weeds, except for Buctril.

“The product Express is a new player in town and does an outstanding job on most broadleaves,” Wright said. “Express works a little slower; taking up to three weeks to kill weeds.”

Express can be tank mixed with several broadleaf herbicides to widen the weed spectrum or hasten the weed kill.

Wright called Axial an excellent grass herbicide which provides good control of wild oats and Italian ryegrass, plus canarygrass suppression. Axial works best when weeds are small and before canopy development. The application timing also depends on which broadleaf weeds are present, and which broadleaf herbicide is in the tank mix.

“Growers tell me a tank mix of Axial, Express, and MCPA have created the cleanest fields they have ever seen,” Wright said.

Nitrogen impact

Nitrogen (N) management and N’s impact on yield and protein were discussed by UCCE farm advisor Steve Orloff of Siskiyou County.

“Yield and protein content are the most important factors in determining profitability,” Orloff said. “Nitrogen management is a critical component to achieve that.”

The application of N fertilizer, plus existing N in the soil and water, impact the total N available for plant uptake. Orloff says N accumulation over the season closely follows an S curve. Uptake is very low at the beginning from emergence to tillering. The plant demand for N increases rapidly from tillering to heading, and then flattens out to maturity.

During the tillering to heading period, a plant can uptake 2 pounds of N per day. At the boot stage, the N uptake is close to 80 percent of the total N uptake during the growing season.

How much N to apply is a key question growers often ask Orloff. The answer depends on many factors, including the growth and N uptake dynamics of the crop, the N amount in the soil from the previous crop, yield potential, irrigation water availability, soil properties, weather conditions, and the class of wheat.

“To optimize N for Western-grown wheat yields, 3.3 to 5.0 pounds of N (from soil, water, and fertilizer) per acre is usually required to produce 100 pounds of grain,” Orloff said.

California grain yields have climbed to about 4 tons per acre in many areas. Some growers have achieved 5 tons/acre.

Orloff calculated, “A 4-ton grain crop requires about 260 pounds of N to achieve a 13-percent protein level. About 280 pounds of N per acre is required to produce 14-percent protein.”

For growers striving for five-ton yields, the figure increases to about 325 pounds of N for 13 percent protein, and about 350 pounds N to achieve 14-percent protein.

Orloff urges growers to sample the soil at 1- and 2-foot depths before planting to determine the soil N level. The N level should be considered as part of the total N amount needed to make the wheat crop.

N utilization trials by Orloff last year, and by Mike Ottman of the University of Arizona, suggest that pre-plant-applied N may not be as beneficial as previously thought. Growers may get more N benefit to make high protein when applied later in the season.

cblake@farmpress.com