The agronomic and economic performance of flax in Iowa

Demand for flax (Linum usitatissimum L.) has increased due to the discovered health benefits of adding flaxseed to human diets. A facility in northwest Iowa that processes organic flaxseed for oil provides a viable market for organic growers in the Midwest. Organic growers are particularly concerned about adequate fertility and weed management when adding flax to their crop rotations. Our objective was to evaluate flax response to N rate and source as well as to ambient weed competition when following either soybean or corn in rotation. The particular response variables investigated were seed yield, straw yield, harvest index, oil concentration of flaxseed, and the linoleic acid and linolenic acid concentrations of flaxseed oil. The experiment was conducted in central Iowa in 2007 and 2008, on land previously sown to either soybean [Glycine max (L.) Merr.] or corn (Zea mays L.). Red clover (Trifolium pratense L.) was underseeded with flax at time of sowing. Nitrogen was applied as composted swine manure, liquid swine manure, or urea. Each source of N was applied at a rate to supply 30, 60, and 90 lb N acre-1. A control where no N was applied (0 lb N acre-1) was also included. Half of each plot was hand-weeded while ambient weed growth was allowed in the other half. Across both years, competition from weeds reduced seed yields by 32% to 96% compared to when weeds were removed. Weed competition reduced straw yield except in 2008 in the field previously sown to corn. In 2007, seed and straw yields increased with N rate, when weeds were removed. Response of seed yield was dependent on N source in the field previously sown to corn but not soybean. Response of seed and straw yield to N was reduced when weeds were not removed. No response of seed or straw yield to N was observed in 2008 regardless of weed competition, likely a result of late planting due to wet field conditions that year. The harvest index was reduced with increased N in 2007 in the field previously sown to soybean, indicating that N increased straw yield disproportionately to seed yield. Competition from ambient weeds reduced oil concentration, linoleic acid concentration, and linolenic acid concentration only in the field previously sown to soybean. Oil concentration of flaxseed was reduced by 0.8% when weeds were not removed. Nitrogen had no effect on oil concentration of flaxseed. Linoleic and linolenic acid concentrations of flaxseed oil were reduced with increasing N, particularly when weeds were not removed. Results indicate that sufficient weed management is necessary for maximum seed yield of flax. Sufficient weed management is also necessary when maximizing seed quality factors such as oil, linoleic acid, and linolenic acid concentrations

The science of cover crops in Iowa

Iowa Cover Crop Working Group (ICCWG) is under the leadership of the Iowa Learning Farms program and includes core members from the following agencies and organizations: Practical Farmers of Iowa (PFI), Iowa State University Extension and Outreach (ISUEO), USDA-Agricultural Research Service-National Laboratory for Agriculture and the Environment (USDA-ARS-NLAE), Iowa Department of Agriculture and Land Stewardship (IDALS)

Evaluating canola (Brassica napus) as an alternative oilseed crop and enhancing winter cover in Iowa

The viability of canola and winter cover crops as alternative ‘third’ crops in Iowa were studied. Though the alternative cropping systems were not as competitive on a production or economic basis, they did show tremendous promise in terms of reducing the potential for soil erosion and the leaching of nutrients into the water

Iowa Crop Variety Yield Testing: A History and Annotated Bibliography

Variety testing by U.S. agricultural universities, often in cooperation with experiment stations, and professional crop associations is recognized as an independent, unbiased validation of the viability of commercial crop varieties. In Iowa, variety testing has also been conducted by many private agricultural companies and individual farmers. Records for crop variety evaluations within the state can be traced back to 1871, well before the creation of the Iowa Agricultural Experiment Station in 1888. The Iowa Corn Yield Test (ICYT) is undeniably the most famous of the Iowa variety yield trials; however, corn (Zea mays L.) varieties were being tested long before that program was initiated. Furthermore, Iowa researchers have been conducting variety yield tests on many other field crops. Knowledge of how Iowa variety tests have been organized and published could be helpful to researchers looking for similar, long-term evaluations from other states and around the world. Variety tests from the past also have the potential to help guide new research efforts and may provide an important untapped resource for unique varietal data. As crop scientists and agronomists look to find new sources for biofuels, bio-products, and other industrial uses for various crops, data from historical varieties could be useful. The objective for this review is to provide an historic account with sections on varietal testing in Iowa. It is presented in chronological order followed by sections devoted to specific crops. A Supplemental Information file containing a detailed annotated bibliography is also provided

Agroecosystems analysis

Contributing institution: Iowa State UniversityPreviously hosted as part of Mann Library's Locale collection

Evaluating alternative, diverse cropping systems that include canola, wheat, and red clover in Iowa

Over the period of 2009-2013, I compared the agronomic, economic, and ecologic performance of three distinct crop rotations at the Iowa State University Agronomy and Agricultural Engineering Research Farm in Boone County. One rotation represented the contemporary norm in Iowa, while the other two rotations included “alternative” crops (canola and wheat) and a forage legume green manure interseeding (red clover). The rotations were a corn-soybean (C-Sb) system, a system common to contemporary Iowa farming operations; and two “alternative” systems: corn-spring canola-winter wheat + red clover (C-SC-WW/RC) and corn-spring wheat-winter canola + red clover (C-SW-WC/RC). All three rotations included transgenic crops, applications of liquid swine manure, synthetic fertilizers, and chemical pesticides; though, I intended for biological N fixation by the red clover green manure and crop competitiveness with weeds to be more heavily relied on in the two alternative cropping systems. The overall purpose of this research project was to provide demonstrations of and more information about alternative, diverse cropping systems for farmers in Iowa. The objectives of this dissertation research were to determine: (i) whether red clover green manure could reduce reliance on purchased N fertilizer for corn production; (ii) the best combination of spring and winter varieties of wheat and canola in terms of yield and quality; and (iii) the financial and soil erosion dynamics among the three rotation systems studied. The alternative systems were not as competitive on a production or economical basis, but they did show tremendous promise in terms of reducing the potential for soil erosion and input costs associated with agriculture, compared to the contemporary C-Sb system common across Iowa.</p

The agronomic and economic performance of flax in Iowa

Demand for flax (Linum usitatissimum L.) has increased due to the discovered health benefits of adding flaxseed to human diets. A facility in northwest Iowa that processes organic flaxseed for oil provides a viable market for organic growers in the Midwest. Organic growers are particularly concerned about adequate fertility and weed management when adding flax to their crop rotations. Our objective was to evaluate flax response to N rate and source as well as to ambient weed competition when following either soybean or corn in rotation. The particular response variables investigated were seed yield, straw yield, harvest index, oil concentration of flaxseed, and the linoleic acid and linolenic acid concentrations of flaxseed oil. The experiment was conducted in central Iowa in 2007 and 2008, on land previously sown to either soybean [Glycine max (L.) Merr.] or corn (Zea mays L.). Red clover (Trifolium pratense L.) was underseeded with flax at time of sowing. Nitrogen was applied as composted swine manure, liquid swine manure, or urea. Each source of N was applied at a rate to supply 30, 60, and 90 lb N acre-1. A control where no N was applied (0 lb N acre-1) was also included. Half of each plot was hand-weeded while ambient weed growth was allowed in the other half. Across both years, competition from weeds reduced seed yields by 32% to 96% compared to when weeds were removed. Weed competition reduced straw yield except in 2008 in the field previously sown to corn. In 2007, seed and straw yields increased with N rate, when weeds were removed. Response of seed yield was dependent on N source in the field previously sown to corn but not soybean. Response of seed and straw yield to N was reduced when weeds were not removed. No response of seed or straw yield to N was observed in 2008 regardless of weed competition, likely a result of late planting due to wet field conditions that year. The harvest index was reduced with increased N in 2007 in the field previously sown to soybean, indicating that N increased straw yield disproportionately to seed yield. Competition from ambient weeds reduced oil concentration, linoleic acid concentration, and linolenic acid concentration only in the field previously sown to soybean. Oil concentration of flaxseed was reduced by 0.8% when weeds were not removed. Nitrogen had no effect on oil concentration of flaxseed. Linoleic and linolenic acid concentrations of flaxseed oil were reduced with increasing N, particularly when weeds were not removed. Results indicate that sufficient weed management is necessary for maximum seed yield of flax. Sufficient weed management is also necessary when maximizing seed quality factors such as oil, linoleic acid, and linolenic acid concentrations.</p

The agronomic and economic performance of the production of flax in Iowa

Abstract not available

The science of cover crops in Iowa

Iowa Cover Crop Working Group (ICCWG) is under the leadership of the Iowa Learning Farms program and includes core members from the following agencies and organizations: Practical Farmers of Iowa (PFI), Iowa State University Extension and Outreach (ISUEO), USDA-Agricultural Research Service-National Laboratory for Agriculture and the Environment (USDA-ARS-NLAE), Iowa Department of Agriculture and Land Stewardship (IDALS).</p