Impact of Planting Date and Seed Treatment on Soybean Yield

Today’s high-yielding soybean varieties respond favorably to early planting. Multi-year results from statewide university research farms suggest that mid-April to early May planting dates produce top yields in most comparisons. Research farm and on-farm strip trials also suggest that elite varieties yield similarly over a wide range of seeding rates and resulting harvest populations. Based on these results, producers are advised to plant soybeans as soon as spring field conditions allow, with a seeding rate of 150,000 to 175,000 seeds per acre. The yield response of modern varieties to early planting raises questions about expanding the soybean planting season (very early planting of some soybean acres in late March or early April) when weather conditions allow. In 2000 a soybean “planting date x seed treatment” study was initiated to evaluate yield response of two adapted, high-yield varieties to very early planting. Research objectives are to determine whether planting soybeans earlier than corn could be a viable management option for Iowa producers, and if fungicide seed treatments are needed to make this practice profitable. Establishment of similar studies at four other university research farms statewide afforded yield response comparisons of adapted varieties from five unique soil associations and environments. Soils at the Armstrong Research Farm are typical of the Marshall-Exira soil association

Planting Date and Seed Treatment Effects on Soybean Yield

Today’s high-yielding soybean varieties respond favorably to early planting. Multi-year results from statewide university research farms suggest that mid-April to early May planting dates produce top yields in most comparisons. Research farm and on-farm strip trials also suggest that elite varieties yield similarly over a wide range of seeding rates and resulting harvest populations. Based on these results, producers are advised to plant soybeans as soon as spring field conditions allow, with a seeding rate of 150,000 to 175,000 seeds per acre

Seed-Applied Fungicides for Very Early Planted Soybeans

Today’s high-yielding soybean varieties respond favorably to early planting. Multi-year results from statewide university research farms suggest that mid-April to early May planting dates produce top yields in most comparisons. Research farm and on-farm strip trials also suggest that elite varieties yield similarly over a wide range of seeding rates and resulting harvest populations. Based on these results, producers are advised to plant soybeans as soon as spring field conditions allow, with a seeding rate of 150,000–175,000 seeds/acre

Enhancing Yield and Biological Nitrogen Fixation of Common Beans

Two studies were conducted at the ISU Horticulture Station to evaluate potential limitations on yield and atmospheric nitrogen fixation by common bean (Phaseolus vulgaris L.). This legume is a food staple for small landholder farm families worldwide. But it has a limited capacity for nitrogen fixation and often yields only a fraction of its genetic potential. In these studies, we examined the dependence of pod filling on current assimilate supply, as well as the potential to improve nitrogen fixation using an inoculant shown to enhance biological nitrogen fixation under stressful conditions

Roundup Ready vs. Conventional Soybean Yield Comparison

Many Iowa soybean producers have adopted Roundup Ready (RR) technology on their farms in recent years. Reduced weed control costs, greater flexibility in herbicide application timing, and the potential for “cleaner” soybean fields are often cited as reasons for using RR technology; however, questions remain about potential profit-robbing yield reductions associated with RR varieties

Using Fungicide-treated Seed for Very Early Soybean Planting

Modern, elite soybean varieties respond well to early planting. Multi-year results from ISU research farms suggest that mid–April to early May planting dates most often produce top yields. Research farm and on-farm strip trials also suggest that elite varieties yield similarly over a wide range of seeding rates and resulting harvest populations. Based on these results, producers are advised to plant soybeans as soon as spring field conditions allow, with a seeding rate of 150,000 to 175,000 seeds/acre

Seed Fungicide Treatments for Very Early Soybean Planting

Today’s high-yielding soybean varieties respond favorably to early planting. Multiyear results from statewide university research farms suggest that mid-April to early May planting dates produce top yields in most comparisons. Research farm and on-farm strip trials also suggest that elite varieties yield similarly over a wide range of seeding rates and resulting harvest populations. Based on these results, producers are advised to plant soybeans as soon as spring field conditions allow, with a seeding rate of 150,000 to 175,000 seeds/acre

Roundup Ready vs. Conventional Soybean Variety Yield Test

Many Iowa soybean producers have adopted Roundup Ready (RR) technology on their farms in recent years. Reduced weed control costs, greater flexibility in herbicide application timing, and the potential for “cleaner” soybean fields are often cited as reasons for using RR technology; however, questions remain about potential profit-robbing yield reductions associated with RR varieties. A soybean yield performance comparison of adapted, elite RR varieties and elite conventional varieties was initiated in 1998. Our research objective was to compare genetic yield potential of commercial varieties, not to analyze the economics of one soybean variety-herbicide program versus another. Establishment of similar studies at four other university research farms statewide afforded yield comparisons of adapted varieties from five unique soil associations and environments. Northeast Research Farm soils are typical of the Kenyon-Floyd-Clyde soil association

Intraindividual Variability in Cortisol: Approaches, Illustrations, and Recommendations

Most of the variance in diurnal cortisol is attributable to intraindividual variability (IIV), defined as relatively short-term, reversible changes. Multiple methods for measuring IIV have been proposed, and some have already been applied to cortisol IIV. In the present review, measurement methods are described and applied to simulated cortisol data with known underlying differences in IIV and to real cortisol data from first-year law students. More slope variance and more residual or net variance were well captured by their individual standard deviations. Explorations of reliability suggested that 10 slopes and 50 residuals result in reliable and stable estimates of the individual standard deviations. A data-analytic plan for cortisol IIV is provided

An information system for estimating, targetting and planning in small building firms.

This thesis outlines the basic problems relating to estimating, targetting and planning functions in small building firms and a possible solution. It was found that information for these functions was rarely integrated and was derived from different sources. It was therefore suspect in terms of accuracy. Four case studies were undertaken and the firms were investigated and analysed in terms of their logical and physical organisation and management systems. Their basic problems were the lack of control of costs, slow feedback of information, low labour productivity and a shortage of staff to carry out the administration work. A general model was derived from the four case studies and this was used to specify the problems in terms of detailed activities and data used. The general model was analysed to derive a prototype system which co-ordinated the data in the different functions by using production oriented, operations, each with a standard performance output. Database management techniques were then used to structure the data effectively so that the prototype system could be implemented using a standard database package on a micro computer. A standard database file of operations was built up for alterations, refurbishment and repair work. A number of estimates were generated and compared to identical ones prepared by hand. All related planning and targetting information was then prepared. It was found that taking off of estimates took a little longer but once completed much relevant planning and targetting information could be generated and feedback obtained. This was all directly related to the estimate due to the integration of the functions. The management information generated allowed better control of costs and outputs with little administrative effort