William J. Wiebold

Planting date and cultivar maturity group (MG) are major management factors affecting soybean [Glycine max (L.) Merr.] yield, but their effect on seed oil and protein concentration, and in particular meal protein concentration, is less understood. We quantified changes in seed oil and protein, and estimated meal protein concentration, and total oil...

Farmers have been interested in using foliar‐applied nutrient products to increase soybean [Glycine max (L.) Merr.] yield since at least the 1970s, despite limited evidence that these products offer consistent yield increases when used prophylactically. Recently, interest in foliar fertilizer products for soybean production has been renewed, likely...

Soybean is the preferred protein source for both poultry and swine feed. However, this preferred status is being challenged due to competition from alternative feed ingredients. To overcome this, it becomes necessary for breeders to develop soybean cultivars that contain higher protein and better nutritional composition. In this study, we have deve...

The effects of supplemental nitrogen (N) on soybean [Glycine max (L.) Merr.] seed yield have been the focus of much research over the past four decades. However, most experiments were region-specific and focused on the effect of a single N-related management choice, thus resulting in a limited inference space. Here, we composited data from individu...

Sorghum [Sorghum bicolor (L.) Moench], has been identified as a crop with multiple uses, including as biofuel feedstock and livestock feed. The biomass‐related industries require a continuous supply of biomass, whereas livestock operations are looking for low‐cost feed alternatives to field corn. Ratooning of a high‐yielding low‐input crop such as...

While soybean [Glycine max (L.) Merr.] production risk is typically managed by planting a range of maturity groups (MGs) across a few different planting dates (PDs), there have been no reports that have quantified changes in risk and profitability using this diversification strategy. Three years of field-trial data from eight locations in six state...

Corn (Zea mays L.) grain composition is important for human and livestock nutrition, when used as seed, and for ethanol production. However, few studies have evaluated the effects of common cultural practices on corn grain composition. This study was conducted to determine whether corn grain elemental composition is affected by tillage practices (t...

Planting date is one of the main factors affecting soybean (Glycine max [L.] Merr.) yield. Environmental conditions in the US Midsouth allow for planting dates from late March through early July, and maturity groups (MGs) ranging from 3 to 6. However, the complexity of interactions among planting date, MG, and the environment makes the selection of...

Soybean is an important protein source for both humans and animals. However, soybean proteins are relatively poor in the sulfur-containing amino acids, cysteine and methionine. Improving the content of endogenous proteins rich in sulfur containing amino acids could enhance the nutritive value of soybean meal. Leginsulin, a cysteine-rich peptide, pr...

The United States is one of the largest soybean exporters in the world. Production is concentrated in the upper Midwest. Much of this region is not irrigated, rendering soybean production systems in the area highly sensitive to in-season variations in weather. Although the influence of in-season weather trends on the yields of crops such as soybean...

Soybean (Glycine max [L.] Merr.) grain composition determines its uses, nutritional quality, value, and the amount of nutrients removed from agricultural ecosystems. Yet few studies have evaluated the effects of annual farming practices on composition. This study was conducted to determine whether soybean grain composition is altered by farming pra...

Soybean [Glycine max (L.) Merr.] contains several health promoting compounds including phytosterols, isoflavones, phytic acid, and protease inhibitors. The two abundant protease inhibitors of soybean seeds are the Kunitz trypsin inhibitor and the Bowman‐Birk inhibitor (BBI). Bowman‐Birk inhibitor has been touted as a potential cancer chemopreventiv...

R iley' (Reg. No. CV-24, PI 663949), a canola-quality win-ter oilseed rape (Brassica napus L.), was tested under the experimental name KS4158 and developed by the Kansas Agricultural Experiment Station. Riley is named for Riley County, the county in which Kansas State University is located. Riley was publicly released in 2010 because of its disease...

The ability of hyperspectral image (HSI) data to provide estimates of soil electrical conductivity (ECa) and soil fertility levels without requiring extensive field data collection was investigated. The relationships between HSI spectral reflectance signatures and soil properties were analyzed to evaluate the usefulness of HSI for quantifying withi...

Understanding the effects of tillage and rotation on plant available nutrients is critical to develop nutrient management strategies to optimize yield while maintaining cropping system sustainability. Our hypothesis is that tillage, and crop rotations with corn (Zea mays L.) compared to continuous soybean (Glycine max (L.) Moench) affects the distr...

Field studies were conducted in 1998 and 1999 to evaluate the sensitivity of a common sunflower population to acetolactate synthase (ALS)-inhibiting herbicides and evaluate alternative control methods for ALS-resistant common sunflower in soybean. Imazaquin, imazethapyr, imazamox, flumetsulam, chlorimuron, cloransulam, and CGA277476 provided 35 to...

Frogeye leaf spot (FLS) of soybean, caused by Cercospora sojina, has been a problem in the southern United States for many years and has recently become a greater problem in the northern United States. Cultivars resistant to FLS have been developed for planting in the southern United States and resistance in many of these cultivars is conditioned b...

Field studies were conducted in 1998 and 1999 to evaluate crop response, weed control, Glycine max yield, and economic returns with sulfentrazone alone and tank-mixed with glyphosate, cloransulam, or chlorimuron at two preplant application timings in no-till, narrow-row, glyphosate-resistant G. max. No significant crop injury was observed. Setaria...

Field studies were conducted in 1998 and 1999 to evaluate crop response, weed control, Glycine max yield, and economic returns of labeled (1×) and one-half labeled (½×) rates of early preplant (EPP) sulfentrazone plus chlorimuron and postemergence glyphosate, compared to glyphosate-alone systems in no-till, narrow-row, glyphosate-resistant G. max....

Crop performance is often shown as areas of differing grain yield. Many producers utilize simple GIS color ramping techniques to produce visual yield maps with delineated clusters. However, a more quantitative approach such as an unsupervised clustering procedure is generally used by scientists since it is much less arbitrary. Intuitively the yield...

To evaluate the extent of the genetic change and its effects on the seed protein composition of soybean cultivars released during the past 60 years, representative ancestral cultivars and those derived from selective breeding were grown in a side-by-side comparison. Total seed protein content, determined by combustion analysis of nitrogen, revealed...

Apparent electrical conductivity (ECa) of the soil profile can be used as an indirect indicator of a number of soil physical and chemical properties. Commercially available ECa sensors can efficiently and inexpensively develop the spatially dense datasets desirable for describing within-field spatial soil variability in precision agriculture. The o...

The introduction of winter canola into the Great Plains will increase crop diversity and may increase profitability of existing cropping systems. In many parts of the region a major limitation of winter canola is winter survival. The objective of this research was to quantify the effect of nitrogen and phosphorus on winter canola survival and crop...

Producers using site-specific crop management (SSCM) have a need for strategies to delineate areas within fields to which management can be tailored. These areas are often referred to as management zones. Quick and automated procedures are desirable for creating management zones and for testing the question of the number of zones to create. A softw...

Measures of soil electrical conductivity (EC) and elevation are relatively inexpensive to collect and result in dense data sets which allow for mapping with limited interpolation. Conversely, soil fertility information is expensive to collect so that relatively few samples are taken and mapping requires extensive interpolation with large estimation...

Soybean (Glycine max [L.] Merr.) protein and oil qualities, with respect to monogastric nutrition, have been linked to the relative abundance of specific protein subunits and fatty acids, respectively. An analysis of field-grown soybean seeds by near-infrared spectroscopy revealed significant differences in their protein and oil contents as a funct...

Producers using site-specific crop management (SSCM) have a need for strategies to delineate areas within fields to which management can be tailored. These areas are often referred to as management zones. Quick and automated procedures are desirable for creating management zones and for testing the question of the number of zones to create. A softw...

The efficiency of the management zone approach to improve fertilizer recommendations relies on accurately locating zone boundaries. The objective of this study was to determine the impact of different techniques of identifying management zones on soil NO3--N and Olsen-P (sodium bicarbonate extractable-P) sampling variability. Soil samples were coll...

Wang, J., Niblack, T. L., Tremain, J. A., Wiebold, W. J., Tylka, G. L., Marett, C. C., Noel, G. R., Myers, O., and Schmidt, M. E. 2003. Soybean cyst nematode reduces soybean yield without causing obvious aboveground symptoms. Plant Dis. 87:623-628. Field experiments were conducted at locations in northern and southern Illinois, central Iowa, and ce...

et al. (1989) modeled ECa as a function of soil water content (both the mobile and immobile fractions), the Apparent profile soil electrical conductivity (ECa) can be an indi- electrical conductivity (EC) of the soil water, soil bulk rect indicator of a number of soil physical and chemical properties. Commercially available ECa sensors can be used...

Apparent profile soil electrical conductivity (EC a ) can be an indirect indicator of a number of soil physical and chemical properties. Commercially available EC a sensors can be used to efficiently and inexpensively develop the spatially dense data sets desirable for describing within‐field spatial soil variability in precision agriculture. The o...

Determining an optimal planting date for grain sorghum [Sorghum bicolor (L.) Moench] is critical to maximize yield and economics of production. Therefore, research was conducted to quantify the response of grain sorghum yield to planting date and hybrid maturity and to develop an optimal planting date window for Missouri growers. Six grain sorghum...

Tillage selection has been identified as a factor that may influence corn response to starter fertilizer. The objective of this experiment was to determine if tillage practices affect corn growth and grain yield response to starter fertilizer. The experiment was conducted near Columbia, MO in 2000 and 2001. The experimental design included three hy...

Reluctance towards implementation of precision agriculture seems to be based upon accessibility to well-trained, knowledgeable people, and the cost and availability to obtain quality education, training, and products. Given that precision agriculture is rapidly changing and the current trend for accelerated information exchange, educators of precis...

Nitrogen fertilizer is typically applied to corn (Zea mays L.) shortly before planting, but there are several reasons why later N applications may be of interest: to spread work away from the busy planting season, to avoid the frequent wet field conditions in spring, to reduce or remedy in-season N loss in wet years, or to allow use of in-season di...

The Precision Agriculture Masters (PAM) Program was initiated to enhance the transfer of technology related to precision agriculture to Missouri's crop producers. The PAM program consists of three parts: the precision agriculture knowledge network available through the Missouri Precision Agriculture Center (MPAC), a research/demonstration program,...

The relationship between hyperspectral and multispectral remotely sensed images and ground based soil and crop information was investigated for two central Missouri experimental fields in a corn (Zea mays L.)soybean (Glycine max L.) rotation. Multiple airborne hyperspectral and IKONOS satellite images were obtained during the 1999 and 2000 growing...

Soybean cultivars (Glycine max(L.) Merr.) infected with soybean cyst nematode (SCN; Heterodera glycinesIchinohe) often show symptoms similar to K deficiency. The objectives of this experiment were to determine if SCN infection affected macronutrient concentrations in soybean seedling vegetative tissues, determine whether increased K fertility can o...

A 53 kDa protein, which accumulates at low levels in non-nodulating Clark soybeans, was purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Polyclonal antibodies were raised against the gel-purified protein. N-terminal sequence analysis identified the 53 kDa protein as the β-subunit of β-conglycinin. Result...

Investigations into the effect of soybean cyst nematode (SCN, Heterodera glycines, Ichinoe) on the yield components of soybean [Glycine max (L.) Merr.] have shown that pod numbers are reduced with increasing SCN initial populations (Pi) present in the soil at planting. The main method by which SCN alters pod numbers is through reductions in the num...

Crop models can be evaluated based on accuracy in simulating several years' yields for one location or on accuracy in simulating long-term mean yields for several locations. Our objective was to see how the ALMANAC (Agricultural Land Management Alternatives with Numerical Assessment Criteria) model and a new version of CERES-Maize (Crop-Environment...

Changes in the carbohydrate (glucose, trehalose, and glycogen) and total protein contents of eggs retained within Heterodera glycines cysts were monitored monthly in a field microplot experiment conducted from March 1993 to March 1995. Treatments included two near-isogenic lines of soybean cv. Clark differing for date of maturity, and one corn hybr...

Experiments were conducted in a field near Portageville, MO, from 1992 to 1994 to determine cultivar and planting date effects on soybean stand, yield, and seed infection with fungi. Soy bean cultivars Asgrow 3733 (maturity group III), Ring Around 452 (maturity group IV). Hutcheson (maturity group V), and Asgrow 6785 (maturity group VI) were each p...

Soil erosion and moisture retention are major concerns of soybean growers. Conservation tillage provides residue cover to reduce soil loss and water evaporation. This study was conducted on a Tiptonville silt loam near Portageville, MO, USA. to determine the effect of tillage system and planting date on soybean [Glycine max (L.) Merrill] root growt...

Isolines for maturity within a common background may be useful in research that attempts to determine the effect of maturity group adaptation on soybean [Glycine max (L.) Merr.] growth or yield. Although the effects of maturity genes on soybean phenology have been studied extensively, little is known about their effects on other soybean characteris...

Experiments were conducted to determine the effects of zinc fertilizers on hatching and soil population densities of Heterodera glycines. In vitro egg hatching in solutions of reagent-grade zinc sulfate and zinc chloride and fertilizer-grade zinc sulfate was significantly greater than hatching in deionized water, whereas zinc chelate fertilizer sig...

Corn (Zea mays L.) is an important source of protein for humans and animals. Because dent corn is highly responsive to nitrogen (N) fertilization, substantial amounts of N are used for corn production. Application of N fertilizer may reduce protein quality of corn kernels through an increase in zein content. The objective of this study was to deter...

A 2-year study was conducted in field microplots to determine the relative importance of soybean phenology and soil temperature on induction of dormancy in Heterodera glycines in Missouri. Four near-isogenic soybean lines differing for maturity date were planted in microplots infested with a race 5 isolate of H. glycines. Soil temperature was monit...

To avoid late summer drought, soybean [Gylcine max (L) Merrill] producers in many southern and border states of the USA modify their cropping systems. Options include use of unadapted cultivars and changing planting dates. Because root function is important to plant health and yield, this study was conducted to determine if planting date and soybea...

Physical characteristics of corn (Zea mays L.) kernels influence end‐use. Agronomic practices including nitrogen (N) fertilization may influence kernel hardness. The objective of this study was to determine if com endosperm characteristics influence the effect of N fertilization on kernel hardness and breakage susceptibility. In 1988, six corn hybr...

Corn (Zea mays L.) is a major source of nutrition for humans and animals. Chemical and physical properties of corn endosperm vary among hybrids, are influenced by genotype and environment, and may affect the crop's response to nitrogen (N) fertilization. The objective of the study was to measure the responses of grain yield and grain N, phosphorus...

Agronomic practices affect corn (Zea mays L.) grain yield and may affect physical and chemical characteristics of corn kernels. These characteristics affect feed, food, and industrial uses of corn grain. Four field experiments consisting of planting date and population combinations were conducted to determine the effect of these agronomic practices...

Oats (Avena saliva L.) is an important protein and mineral source for humans and animals. Few data exist that relate cultural practices to oat grain nutritional quality. A split‐plot design was used to evaluate the influence of the four main treatment seeding rates (36,72, 108, and 143 kg/ha), and four split treatments of N fertilizer applications...

Enhancement of written communication skill is a proper objective of undergraduate curricula. This paper discusses the use of two short writing assignments and a peer review in Agronomy 411, Grain Crops, to improve writing skills of under-graduate students and to enhance learning of agronomic prin-ciples. The specific objective of this study was to...

Abscission probability differs among floral positions within soybean [Glycine max (L.) Merr.] racemes, with proximal flowers much less likely to abscise than distal flowers. The objectives of this research were to measure phloem and xylem areas within the rachises of developing soybean racemes, to determine if the sizes of the vascular tissue areas...

Cold hardiness and fall dormancy in alfalfa (Medicago sativa L.) are positively associated, although this relationship is not always desirable for maximum production. The purpose of this study was to determine basic genetic information about cold hardiness and dormancy utilizing six parents differing in their cold hardiness and fall dormancy and th...

Abscission probability varies among floral positions within soybean (Glycine max (L.) Merr.) racemes. Field grown soybean plants were used to determine the distribution of translocated ¹⁴C-labeled photosynthate and abscisic acid (ABA) among reproductive structures differing for abscission probability. The effect of proximal pods on the transloca...

Abscission probability for positions within a soybean [Glycine max (L.) Merr.] raceme may not be equal. The influence of the two most proximal pods on abscission probability and growth of remaining pods within a raceme was studied using the soybean cultivar ‘Williams’. Plants were field grown (1982, Beltsville silt loam, Typic Fragiudult; 1983, Mat...

Soybeans (Glycine max (L.) Merr.) have a high N requirement which is fulfilled by soil N uptake and N2-fixation. This study was concerned with the effects of past yield selection on N2-fixation in soybeans. The soybean cultivars, ‘Lincoln’, ‘Shelby’, and ‘Williams’, which represent successive improvements in the ‘Lincoln’ germplasm, and a non-nodul...

Four soybean [ Glycine max (L.) Merr.] cultivars differing in susceptibility to iron (Fe) chlorosis in wet calcareous soils were grown in nutrient solutions to characterize the effects of phosphate (P) and bicarbonate (HCO ‐ 3 ) in inducing chlorosis. NaHCO 3 (0 or 10 m M ), P (10 or 400 µ M as NaH 2 PO 4 , and NH ⁺ 4 (0 or 300 µ M ) as (NH 4 ) 2 S...

Reproductive abscission is greatest in the lower one‐third of soybean ( Glycine max L. Merr.) canopies. It has been hypothesized that low carbohydrate availability is responsible for abscission of soybean flowers and pods, The cv. Williams was used to determine canopy distribution of flower and pod number, reproductive abscission, and the concentra...

Six bicarbonate and 2 Fe levels were used in nutrient solution to determine the optimum treatment combination for detecting small differences in Fe chlorosis resistance among soybean cultivars. The cultivars tested represented chlorosis resistant (Lakota, Hawkeye, Chippewa‐64, and Hodgson) and chlorosis susceptible (Williams, Hark, Anoka, and Wayne...

Nitrogen contributions of legumes to grass-legume mixtures are estimated on the basis of legume monocultures and may need to be adjusted to reflect any effect of the companion grass. An experiment at two field locations was conducted to determine whether the N2-fixation rates of alfalfa (Medicago sativa L.) and red clover (trifolium pratense L.) we...

Evidence suggests that photosynthate production may be yield‐limiting in soybeans [Glycine max (L.) Merr.]. This study was designed to estimate potential for selection of CO 2 ‐exchange rate (CER), specific leaf weight (SLW), leaf thickness (LT), and leaf density (LD) in early generations of soybeans. Two crosses (‘Amsoy’ ✕ ‘Ford;’ ‘Corsoy’ ✕ ‘Hawk...

Although soybeans (Glycine max L. Merrill) are considered to have relatively high levels of reproductive abscission, most studies have used only one or two cultivars and cultivar differences for abscission have rarely been reported. This study determined the abscission levels for 11 field-grown, determinate soybean cultivars (Maturity Groups V, VI,...

The objectives of this study were to estimate leaf area index (LAI) as a function of imagederived vegetation indices, and to compare measured and estimated LAI to the results of crop model simulation. Soil moisture, crop phenology, and LAI data were obtained several times during the 2001 growing season at monitoring sites established in two central...