Iowa Soybean Promotion Board, August 31, 2001 & August 31, 2002

State Agency Audit Report

Iowa Soybean Promotion Board, August 31, 2002 & August 31, 2003

State Agency Audit Report

Iowa Soybean Promotion Board, Independent Auditor's Reports, Financial Statements and Supplemental Information, Schedule of Findings, August 31, 2003 & 2004

State Agency Audit Report

Iowa Soybean Promotion Board, Independent Auditor's Reports, Financial Statements and Supplementary Information, August 31, 2004 & June 30, 2005

State Audit Reports

Evaluation of Soybean Varieties Resistant to Soybean Cyst Nematode in Iowa, 2007

Use of resistant soybean varieties is a very effective strategy for managing soybean cyst nematode (SCN), and numerous SCN-resistant soybean varieties are available for Iowa soybean growers. Each year, public and private SCN-resistant soybean varieties are evaluated in SCN-infested fields throughout Iowa by Iowa State University personnel. The research described in this report was performed to assess the agronomic performance of maturity group (MG) I, II, and III SCN-resistant soybean varieties and to determine the effects of the varieties on SCN numbers or population densities.

Managing Soybean Cyst Nematode, 2007

Soybean cyst nematode (SCN) causes the greatest yield loss of any single pathogen of soybean in Iowa. An estimated 50 million bushels were lost in Iowa to SCN in 2004. Damage from SCN is not limited to yield loss from root feeding; SCN also makes other diseases like sudden death syndrome, iron deficiency chlorosis, Pythium, Phytophthora root and stem rot and brown stem rot worse. Once established in a field, SCN cannot be eradicated. However, the use of multiple management tactics can help minimize yield loss.

Managing Soybean for High Yield, 2007

Producers continually strive for high yielding soybeans. The state-wide average yield for Iowa is now more than 50 bu./acre. The “yield plateau” reported by many producers does not exist, and is a perception largely brought on by misuse of an oversimplified management system. High yielding soybeans are achieved through improved and targeted management decisions. Improved agronomic decisions for soybeans are critical since soybean is very sensitive to stresses that influence soybean growth, development and yield.

Optimum Plant Population in Iowa, 2007

As a result of higher seed prices, improved planters and weed management programs, soybean growers are more aware of the importance of seeding rates and optimal plant populations at harvest. A harvest population of approximately 100,000 uniformly distributed plants per acre will maximize economic return in Iowa regardless of row spacing. There appears to be no economic advantage to harvest populations greater than, or less than, 100,000 plants per acre. Economics, however, should be considered carefully when striving for higher harvest populations since seed is expensive. Timely management, such as weed management, is more critical at low plant populations.

Optimum Plant Population in Iowa, 2007

As a result of higher seed prices, improved planters and weed management programs, soybean growers are more aware of the importance of seeding rates and optimal plant populations at harvest. A harvest population of approximately 100,000 uniformly distributed plants per acre will maximize economic return in Iowa regardless of row spacing. There appears to be no economic advantage to harvest populations greater than, or less than, 100,000 plants per acre. Economics, however, should be considered carefully when striving for higher harvest populations since seed is expensive. Timely management, such as weed management, is more critical at low plant populations.

Soybean Planting Date, 2007

The planting date for soybeans should be based on seedbed conditions and calendar date rather than soil temperature. The optimum time to plant soybeans in Iowa is the last week of April for the southern two thirds of Iowa and the first week of May for the northern one third of Iowa.

Soybean Planting Date, 2007

The planting date for soybeans should be based on seedbed conditions and calendar date rather than soil temperature. The optimum time to plant soybeans in Iowa is the last week of April for the southern two thirds of Iowa and the first week of May for the northern one third of Iowa.

Business Sphere, Vol. 19, no.2

The first commercial quantities of a soybean oil with about three percent linolenic acid oil were produced in Iowa in 1994 through a collaboration with Pioneer Hi-Bred International, Inc. Continued to breed new soybean varieties with a focus on a even lower linolenic acid content of one percent. I was interested in understanding whether the oil would be stable enough to eliminate the need for chemical hydrogenation. During the process of increasing one percent linolenic acid seed varieties to obtain oil for testing, the Food and Drug Administration announced it would require labeling for trans fat beginning in 2006. Instead of using the seed of the new varieties to obtain oil for testing, it was used for further seed production so that commercial quantities of the one percent linolenic acid oil could be available as quickly as possible.

How a soybean plant develops,1982.

This special report from the Iowa State University Cooperative Extension Service, no. 53. is designed to aid those involved in soybean production to more fully understand how the soybean plant develops. The content is both basic and applied. The basic information explains soybean growth and development through one life cycle. Management guides pinpoint practices needed for optimum plant growth and production.

How a soybean plant develops,1985.

This revised special report from the Iowa State University Cooperative Extension Service, no. 53. is designed to aid those involved in soybean production to more fully understand how the soybean plant develops. The content is both basic and applied. The basic information explains soybean growth and development through one life cycle. Management guides pinpoint practices needed for optimum plant growth and production.

Do fire and seed additions alter strong seed timing and priority effects on prairie establishment?, 2011

Many prairie restoration projects are hampered by a lack of knowledge on how to restore the high diversity found in prairies, while at the same time preventing the establishment of a large weedy component. Methods are needed to increase diversity and abundance of native species while minimizing exotic species invasions in both 1) newly planted restorations and 2) established restorations. We established an experiment in Story and Monona counties in 2005 to determine the effects of different native cover crop species and timing of seeding on the establishment of new prairie restorations. We found that adding a 30-species prairie mix in early spring led to diverse native communities, but adding the mix in the late summer or the following year after cover crops established led to low diversity communities dominated by exotics. The identity of cover crops affected communities less than timing of seed additions. A second seed addition added to ash after a spring fire in the seventh year (Monona County site) increased recruitment from the prairie mix slightly, but the increase was not enough to cause convergence in the treatments. Surprisingly, the second seed addition increased diversity only in communities that were already the most diverse (i.e., in plots seeded with the prairie mix in early spring before cover crops established). These results imply that 1) cover crops are not effective for establishing prairie and 2) over seeding into established plots may not be an easy and efficient way to increase native recruitment and lower weedy species abundances. Therefore, focusing on establishing high levels of recruitment and diversity and excluding weedy species during the critical time early in establishment should be a priority for new projects.