Overview and Perspective - Feed Grains: Vital to Louisiana Agriculture

Stephen Harrison, Benedict, Linda F.  |  10/27/2006 11:44:49 PM

Stephen A. Harrison, Professor, Department of Agronomy & Environmental Management, LSU AgCenter, Baton Rouge, La. (Photo by John Wozniak)

Stephen A. Harrison

The feed grains are a diverse group of crops, each with a unique set of problems, challenges and opportunities. Feed grains in Louisiana include corn, grain sorghum (milo), wheat and oats. Along with rice and millet, these cereal crops comprise a large portion of the total calories and protein consumed worldwide. Most of the feed grains produced in Louisiana enter the export market through the expansive Mississippi River grain elevator system that handles a large portion of the nation’s grain production. Grower interest and subsequent acreage of the feed grains depends on farm programs and weather conditions. With the current world shortage of wheat and a market hungry for ethanol, the outlook for feed grain production in Louisiana is bright.

Corn No. 1
Corn is the most widely grown feed grain in Louisiana and has the greatest economic impact on the state. From 2002 until 2005, corn was harvested from an average of 439,000 acres each year with an average gross farm value of more than $133 million. Corn acreage reached a high of 700,000 acres in 1998. Corn acreage is influenced by several factors including relative commodity prices, fertilizer prices, concerns over aflatoxin, and March and early April weather.

The majority of Louisiana’s corn is produced along the Mississippi River from the northeast down through the east central region and back up through the Red River Valley to northwest Louisiana. Corn is an excellent rotation crop with soybeans and cotton, offering improved soil organic matter and tilth, pest and disease control, and increased profitability of the cropping system. All U.S. corn are hybrids developed by private industry, and many contain transgenic traits such as RoundUp herbicide resistance and Bt insecticidal proteins. LSU AgCenter scientists conduct research programs to evaluate hybrid performance across multiple environments; evaluate seeding rates, row spacing and planting dates; determine optimum fertility programs; and develop effective weed control and disease management systems.

Threat of Aflatoxin
Aflatoxin is a microtoxin produced under certain environmental conditions by the fungus Aspergillus flavus. Aflatoxin contamination can be devastating and is a major factor limiting corn production in Louisiana. Heat and drought favor production, and no hybrids have high levels of resistance to the fungus or to aflatoxin biosynthesis. A severe epidemic in 1998 prompted LSU AgCenter scientists to initiate a comprehensive research program that includes the aggressive pursuit of new sources of resistance. They are evaluating the reaction of available hybrids and the efficacy of various chemical and cultural practices to limit aflatoxin production. Their strategies include control of insect pests that may facilitate aflatoxin accumulation and methods to decrease aflatoxin accumulation.

In a search for sources of genetic resistance to aflatoxin, more than 1,600 corn lines in the U.S. Department of Agriculture world collection have been hybridized to a common female parent to ensure adaptation, and the resulting F1 hybrids were screened for resistance to aflatoxin at the Dean Lee Research Station at Alexandria. Development of adapted hybrids from resistant lines identified in this manner will ensure that Louisiana growers reap the benefits from this research.

In years like 1998, early harvest along with cultural practices such as irrigation may minimize aflatoxin production. Researchers are evaluating the use of glufosinate (Liberty) herbicide, which may lower aflatoxin in infected corn. Another approach uses nontoxin-producing strains of the organism to competitively inhibit infection with toxin producers.

Corn Insect Control
Corn borers cause substantial yield losses in Louisiana and are believed to contribute to infection by Aspergillus flavus. More than 40 percent of the corn in Louisiana is planted with Bt hybrids to control borers. This corn (YieldGard and Herculex) has an inserted gene that causes the corn plant to produce proteins fatal to insects. Though a wonderful tool for borer control, widespread use, or misuse, can result in development of insect populations resistant to these toxins, thereby removing Bt hybrids as a management option. Entomologists with the LSU AgCenter are developing Insect Resistance Management (IRM) and monitoring strategies to ensure maximum benefit to growers from this innovative technology. AgCenter scientists also are evaluating control methods for sugarcane beetles in corn and several insect pests in sorghum.

Wheat and Oats
Wheat offers growers the advantage of cash flow in the summer and fits well into rotation systems. Wheat was produced on an average of 150,000 acres from 2002 through 2005 and had an average gross farm value of about $24 million. Wheat is produced in the same parishes as corn, along with some acreage in the rice region of Southwest Louisiana. Oats for grain are produced on about 5,000 acres per year, with additional acreage planted for use as winter pasture. More than 500,000 acres of wheat were grown by Louisiana producers during the 1984-85 season, one marked by record-high prices similar to those currently seen. Wheat acreage in Louisiana is determined by relative commodity price, nitrogen fertilizer price and weather during planting season.

Developing Wheat Varieties
The LSU AgCenter has long been a leader in the development of superior crop varieties and has released numerous varieties of sugarcane, rice, cotton, sweet potatoes and other crops. The small-grain breeding program joins this tradition as a leader in the development of wheat and oat varieties adapted to the Gulf Coast region. It is the only wheat breeding program in the region. No commercial wheat breeding programs exist south of Memphis, Tenn., so the industry is dependent on public plant breeders for a continued supply of improved varieties suitable for production in the region.

The AgCenter led in establishment in 2005 of SUNGRAINS, a southeastern university cooperative small-grain breeding program that involves the universities of Florida, Georgia, Clemson and North Carolina State and the LSU AgCenter. The AgCenter has developed and released 10 wheat and oat varieties since 1997, and SUNGRAINS breeders, collectively, have released 34 wheat, 14 oat, six rye and five triticale varieties.

Wheat Opportunities
Wheat yields in Louisiana are highly variable across individual farms and regions of the state and over time. Much of this variation can be attributed to weather patterns and soil types, but a lot can be attributed to variation in cultural practices and individual choices made by growers. Wheat is sometimes treated like a second-class citizen with little attention to proper decision making and management. Grain yields on individual farms range from fewer than 30 bushels per acre to more than 80 bushels per acre, with documented yields of more than 100 bushels per acre on commercial fields. Clearly, AgCenter scientists have many opportunities and challenges to continue to develop improved methods of wheat production and management, leading to stable yields at high levels, reduced risks associated with planting and harvest, and decreased losses from diseases and insects while minimizing production costs. The AgCenter also will be challenged to find new ways to communicate these data to growers in a manner that ensures they adopt the best recommendations.

Disease, Weeds
Stripe rust has become a major wheat disease problem in Louisiana in the past 10 years, reducing yield and quality and increasing production costs because of the need for one or two fungicide applications. Stripe rust spreads more rapidly and is harder to control than leaf rust, which makes it necessary to devise improved methods of fungicide application and forecasting and resistant varieties. AgCenter scientists have conducted fungicide trials across four locations since 2001 to determine which rates, combinations and application timings are most effective in reducing yield and test weight loss from stripe rust epidemics. Since 2000, the AgCenter wheat breeding program has released three stripe rust-resistant varieties that produce high yields or good-quality grain without the need to apply fungicides.

Stand establishment is critical to wheat production, and poor stands often lead to weed competition and reduced yields. Seeding rate studies conducted at the Macon Ridge Research Station at Winnsboro found that high yields can be obtained with sub-optimal wheat stands if fields are maintained weed-free and managed properly to encourage good growth and tillering (the development of multiple stems per plant) during the winter. Seeding rates as low as 8 seeds per square foot (33 percent of recommended rates) yielded as much as the full seeding rate because of profuse tillering.

Weed control in wheat is important, particularly if stands are light and growing conditions poor. Scientists at the Northeast and Dean Lee research stations have evaluated herbicide combinations and rates for control of ryegrass, annual blue grass and other winter weeds in wheat. Sencor herbicide is widely used for weed control in Louisiana wheat fields, but not all varieties are tolerant and damage can occur. Entries in the statewide variety trials are screened each year to determine their reaction to normal and high rates of Sencor.

Grain Sorghum
Grain sorghum was produced on 108,000 acres with an average gross farm value of nearly $25 million each year from 2002 through 2005. Much of the grain sorghum acreage is located in the east central Louisiana, with a smaller acreage in the cotton belt of northeast Louisiana. Grain sorghum acreage fluctuates depending on commodity prices and weather during corn planting season, since sorghum can be substituted for corn in cropping systems and is planted later than corn. Hybrid performance trials are conducted at six locations each year to determine grain yield, harvest moisture, heading date, plant height, head exertion, head type, lodging, and bird and insect damage ratings. Results of these trials are published on the LSU AgCenter Web page and in variety recommendation newsletters. Insecticides for the control of the headworm complex and midge in grain sorghum are evaluated each year. The influence of row configuration (multiple rows per bed) and seeding rate on yield performance of grain sorghum hybrids differing in maturity has also been evaluated.

Funding
Much of the funding to support AgCenter feed grains research and extension programs is provided by state and federal appropriations, but these funding sources have not been adequate to sustain these programs at the level needed to address emerging issues. Grants and other funding have become necessary to enhance programs and allow development in new directions. Notable among these funding sources is the feed grains check-off administered by the Louisiana Soybean and Grain Research and Promotion Board, which provided more than $350,000 per year to AgCenter scientists in 2005 and 2006. Promotion board funding is directed by producers and addresses issues that have direct impact on production agriculture. Research grants from the USDA support research that addresses regional and national concerns such as developing new sources of resistance to stripe rust. Industry grants, variety testing fees and royalties collected from the sales of varieties developed by the AgCenter also contribute to program sustainability.

Future of Feed Grains
This magazine presents a variety of research and extension activities conducted by AgCenter scientists to solve problems and provide solutions for Louisiana feed grain producers. There are many challenges and opportunities for feed grains as we progress toward a new farm bill and evaluate new uses and markets. Nationally, ethanol will consume about 1.8 million bushels of corn in 2006, and this market is rapidly expanding. The effect of increased ethanol production will create more demand for grain, and a tremendous amount of interest in biofuels may provide other alternative uses for feed grains crops. AgCenter scientists will continue to develop and evaluate new varieties, cropping systems and technologies that ensure feed grains remain an integral component of Louisiana agriculture.

(This article was published in the fall 2006 issue of Louisiana Agriculture.)
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