VIRGINIA TECH Small Grains Specialist Wade Thomason right and Wheat Breeder Carl Griffey discuss crop yields at a recent field day

VIRGINIA TECH Small Grains Specialist Wade Thomason, right, and Wheat Breeder Carl Griffey discuss crop yields at a recent field day.

Southeast corn yields trending down, soybeans up

• Over the past five years corn yields in Virginia have averaged 102 bushels per acre. In North Carolina the five-year average stands at 106 bushels per acre. • Clearly these numbers fall significantly short of the national corn yield trend. • Soybean growers in the Southeast can grow yields comparable to growers in the Midwest, if there is adequate rainfall throughout the growing season.   

In recent years many Southeast growers have accepted as fact that corn yields are going up and they can never compete with the Midwest for yields of wheat and soybeans.

Soybean and wheat growers in the Southeast can bask in the glow of the reality that their yields are on the steady incline.

However, corn is a different story, and across most Southeastern states 10-year corn yields are trending down.

Over the past five years corn yields in Virginia have averaged 102 bushels per acre. In North Carolina the five-year average stands at 106 bushels per acre.

Clearly these numbers fall significantly short of the national corn yield trend.

Similar up and down production trends can be found in other Southeast states.

The National Corn Growers Coalition, established in 2008 by the National Corn Growers Association, makes a poignant case for the productivity of corn: “Farmers today grow five times as much corn as they did in the 1930s — on 20 percent less land. That is 13 million acres or 20,000 square miles, twice the size of Massachusetts. The yield per acre has skyrocketed from 24 bushels in 1931 to 154 now, or a six-fold gain.

The decline in corn production in Virginia is mostly weather related.

“I work every year with corn varieties, and I know yield based on varieties is going up. I think there have been similar advances in production technology, so about the only variable left is weather,” says Virginia Tech Small Grains Specialist Wade Thomason.

Jerry Stoller, president of Stoller Enterprises, says there is a much more economical approach than irrigation to solving the up and down, weather-related corn yields many growers in the Southeast have seen the past few years.

Damaged by drought

In tests by North Carolina State Corn Specialist Ron Heiniger, Stoller says corn plots planted in 2011 were severely damaged by drought.

“On some treatments the average corn yield was 36 bushels per acre. Where Heiniger applied a product called More Power (produced by Stoller Enterprises, Inc.) the yield on this field was 118 bushels per acre.

Stoller says, “In explanation, corn plants need soil moisture in order to evaporate moisture from the plant leaves. This serves as an air conditioning system in a plant to keep plant tissue cool so that the plants can continue to carry on photosynthesis.

“When plant tissue becomes too hot, the process of photosynthesis decreases and eventually is eliminated. The hot temperatures do not allow the sugars to move out of the plant cells into other parts of the plant. The plant cells then starve from the lack of energy. Photosynthesis stops and the plant cells die.”

On the other hand, he says, “If photosynthesis of the plant can be maintained under hot temperatures, the plant cells will receive enough sugars to carry on normal respiration. During the process of respiration, plant cells make their own water as a by-product from fermentation of sugar. This is enough water so plant cells can function normally,” Stoller explains.

Steve Speros, who markets Quick-Sol in North Carolina, says his product produces a similar response in corn. And, Michael Cohen, who is sales and marketing director for Actosol, says his product improves stress tolerance, water retention, enhances chelating of plant nutrients, improves phosphorous uptake, and stimulates root mass and plant growth.

Though these materials, and others like them, all work in different ways, growers report significant corn yield increases in drought years using a number of such products. Whether these new products stand up to rigorous testing at Land-Grant universities, over a period of years, remains to be seen.

Whether it be from using irrigation moisture or water- enhancing materials, the key to producing more uniform corn yields in the Southeast seems to be getting moisture to the plant at the key time in the growth process.

Other spring-planted grain crops grown in the Southeast are subject to the same weather patterns, but don’t appear to be so negatively affected by weather. In fact, soybeans and wheat have shown a steady climb in yield trend over the past 10 years.

Virginia soybeans

In Virginia, Soybean Specialist David Holshouser says, “Trend line yields for Virginia since 1995 are moving up an average of 0.44 bushels per year (versus 0.5 bushels for the entire USA).  Our trend line yield was at 27 bushels per acre in 1995 and at almost 35 bushels per acre in 2010.”

Wheat yields should be hurt more than any other grain crop grown in the Southeast, if for no other reason than the crop stays in the ground longer than any other grain crop. It is left vulnerable to early freezes in the fall and late freezes in the spring, and other bad weather from planting in October to Harvest in May or June.

Despite its vulnerability to weather, wheat has done well over the past 10 years. Clearly a lot of the increased production in the Upper Southeast is enhanced by a very strong wheat breeding program conducted by Virginia Tech Plant Breeder Carl Griffey.

Small Grains Specialist Thomason says, “Wheat acreage is up across the Upper Southeast, prices remain good and the future looks even better, based on continued yield increases in statewide variety tests.

Thomason says the average yield of wheat varieties in statewide testing from 2000 to 2009 has gone up an average of 2.8 bushels per acre per year.

“Basically, we haven’t changed the way we manage these test plots since 1999, so most of the increase is due to genetic improvement. Even more surprising is an annual increase of nearly a pound of test weight during that eight-year time frame,” Thomason says.

Holshouser says soybean growers in the Southeast can grow yields comparable to growers in the Midwest, if there is adequate rainfall throughout the growing season. 

“We can yield with the Midwest, but we have to have the rainfall.” 

He explains that most areas of the Southeast don’t have high water-holding capacity soils like growers have throughout the Midwest.  As one grower recently stated, “We’re only 10 to 14 days away from the last rain to a drought,” Holshouser says.

He lists five primary reasons for the 15-year trend improvement in soybeans in Virginia:

• Residue-building practices that include continuous no-till, cover crops, and/or incorporating high-residue crops in the rotation such as wheat and corn. These practices are building our organic matter and soil structure and fertility, which allow us to tolerate droughts much better and also take better advantage of higher-yielding varieties in good years.

Precision planting

• Precision planting that includes narrow-rows (15 inches or less), more uniform seed placement within a row (we’ve seen a shift from drills back to narrow-row planters or to precision-seeding drills), better soil-to-seed contact, and the use of fungicide-treated seed in cool soils.

• Better pest management. The big one is better weed control with Roundup Ready crops (although this is changing with the resistance problems). We are also doing a much better job at controlling insects and disease when we need to. Our corn earworm, aphid, and now stinkbug survey plus utilizing threshold-based insect management strategies are working. We are putting more fungicides on reproductive-stage soybean.  Overall, this is probably bumping our yields up a little; but, many acres are being treated that probably doesn’t need to be.  We are working on some weather models to help with this.

• Better genetics, especially under high-yielding situations. I do question yield improvements (due to genetics) under lower-yielding years.

• And probably most important, more attention is being paid to the soybean crop, especially in our traditional cotton/peanut or tobacco growing regions.  Soybeans is now our most profitable crop, so farmers are paying more attention to it.

Last year in Virginia, corn, soybeans and peanut yields were all up significantly over the previous year. The obvious reason for increased crop production last year — weather.

“Two years ago, I had the worst crops I’ve had in more than 30 years of growing grain in Virginia and last year, I had the best crops I’ve ever had. This year, who knows, says Hannover, Va., grower Wayne Kirby.

To further validate Kirby’s comments, the Virginia Department of Agriculture released the following updates on the 2011 crop, just prior to planting time for the 2012 crop.

“Corn production up 93 percent over 2010, soybean production up 53 percent, hay up 42 percent; Virginia peanuts produce record yield, up 80 percent from 2010.”

The same report says, “that corn for grain yields averaged 118 bushels per acre, up 51 bushels from the previous year’s yield. Production is estimated at 40.1 million bushels, 93 percent above the 2010 production.

“Corn for grain harvested area was 340,000 acres, up 30,000 acres from last year. Corn silage harvested acreage totaled 130,000 acres, with an average yield of 16.5 tons per acre.

“Soybean yields averaged 39 bushels per acre, up 13.0 bushels from last year. A total of 550,000 acres were harvested for grain, an increase of 10,000 from last year’s soybean acreage.

“Soybean production is estimated at 21.5 million bushels, 53 percent more than last year’s production.

“Virginia’s peanut producers harvested 16,000 acres, down 2,000 acres from 2010. Peanut yields averaged 3,800 pounds per acre, up 1,920 pounds per acre from last year.

“This is a record yield surpassing the previous record of 3,700 pounds in 2009. Peanut production is estimated at 60.8 million pounds, up 80 percent from the 2010 production.”

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