East-central Nebraska Research Articles

Hilling as a cultural control strategy for soybean gall midge (Diptera: Cecidomyiidae).

Soybean gall midge, Resseliella maxima Gagné, was recently identified as a new species causing significant injury to soybean and is currently found in 164 counties across 7 midwestern states (NE, IA, SD, MN, MO, ND, and KS). Infestation of soybean begins in late spring, when adults emerge from last year's soybean field. Infestation of a new soybean crop depends on the presence of fissures which start to form at the base of the soybean plant around the V2 stage. Field observations indicate that these fissures are only present below the cotyledonary nodes or in the area within 3-5 cm above the soil surface. To determine the importance of these fissures for R. maxima infestation and plant injury, hilling or the movement of the soil to cover the base of soybean plants at the V2-V3 stage was compared with the standard practice (no-hilling). Field studies were conducted at 3 sites in east-central Nebraska during the 2021 growing season. The results showed a significant reduction in the frequency of infested plants, larval number per plant, and plant injury for hilled compared to no-hill treatment. This reduction in the presence of larvae and plant injury corresponded with a significantly greater yield for hilled compared to the no-hill treatment. These results highlight the importance of fissures on soybean for R. maxima adult infestation as well as the potential for hilling to be used as a management strategy for R. maxima.

Evaluating management zones and crop‐sensing relationships for improved irrigated maize nitrogen management

AbstractActive crop canopy sensors and management zones (MZ) are two methods of directing variable‐rate, in‐season nitrogen (N) fertilizer applications in maize (Zea mays L.). Researchers have suggested that integrating these two approaches may result in improved performance of sensor‐based N application algorithms through increased N use efficiency and profitability. The objectives of this research study were to (1) identify soil and topographic variables that are related to in‐season canopy reflectance and yield for soil‐based MZ delineation and (2) determine if delineated MZ can identify areas with differential crop response to N fertilizer. N ramp blocks were placed end‐to‐end in field‐length strips at eight irrigated maize fields in east central Nebraska in 2016 and 2017. Maize response to N was evaluated with in‐season canopy reflectance measurements and grain yield. Relationships between maize response variables and measured soil and topographic attributes were evaluated and used to delineate MZ. Yield response to N rate was highly variable among and within fields. Soil apparent electrical conductivity had the highest overall correlations with crop response and was used as a clustering variable in five of eight fields. Economic analysis showed a potential advantage to using soil‐based MZ compared to producer‐chosen uniform N rates in five of eight fields. Delineated MZ were able to identify areas with differential soil properties and crop response to N fertilizer. Integrating soil‐based MZ and sensor‐based N management has potential to achieve further economic benefits.

Inter-relationships between water depletion and temperature differential in row crop canopies in a sub-humid climate

Irrigation has a great impact on global food security as it contributes to the majority of the world’s agricultural food supply. It is essential to judiciously utilize water resources through efficient irrigation management since the majority of U.S. groundwater aquifers are rapidly depleting. Thus, quantification of the relationships between water depletion and environmental factors is important for understanding crop response to varying levels of water stresses that depletion can cause. The objectives of this research were to: 1) investigate the relationship between root zone water depletion (Drw) and canopy temperature differential (ΔT) at different ranges of Drw; and 2) develop upper (water stressed) and lower (non-water stressed) baselines for quantification of crop water stress index (CWSI) in a sub-humid climate. The research was conducted over maize and soybean during 2018, 2019, and 2020 growing seasons. Sensor node stations comprising of an infrared thermometer and three soil water sensors were installed at various sites over maize and soybean fields. ΔT tends to increase with the increase in Drw when the range of Drw includes values greater than 170 mm for maize and values greater than 160 mm for soybean. The results indicate that ΔT and Drw are unrelated until a soil-water depletion threshold is attained, and these Drw threshold values could be considered as indicators to trigger irrigation for efficient agricultural water management. To the best of the authors’ knowledge, the research is the first to develop upper and lower CWSI baselines for east-central Nebraska. The baselines developed in this study could facilitate the quantification of CWSI for irrigation scheduling of maize and soybean in east-Central Nebraska. Future work should aim to investigate the potential in using Drw and/or ΔT to determine efficient water allocation and if a threshold CWSI could be used for timing of irrigation to prevent yield loss.

Arikara and Pawnee Personal Names

This article describes the personal names and naming practices of the Pawnee and Arikara, Northern Caddoan tribes formerly in east-central Nebraska through eastern South Dakota. Personal names among Native American groups have received only passing attention from anthropologists and linguists. However, Caddoan names constitute an intriguing class in both their morphological composition and in the association of particular grammatical structures with age, status, and gender. The study draws on censuses, historical documents, and fifty years of linguistic documentation among the two tribes, which together provide a database of over seven hundred names for each the Pawnee and the Arikara.

Anthropogenic hydrometeorological changes at a regional scale: observed irrigation\u2013precipitation feedback (1979\u20132015) in Nebraska, USA

Long-term tendencies in annual, seasonal, and monthly (March) precipitation, evapotranspiration, and air- and dew-point temperature values were correlated with county-level changes in irrigated area across Nebraska over the 1979–2015 period. A statistically significant linear relationship (slope of − 1.65 ± 0.33 mm decade−1 per % decadal change in irrigated area, with a correlation coefficient of − 0.47) was found between the trends in annual precipitation and irrigated land area. Precipitation dropped by 1 mm annually if the level in irrigation expansion reached about 8% per decade, while the rest of the state enjoyed about a half-millimeter overall increase in annual precipitation rates. The drop was not evenly distributed within the year: the largest decrease took place in the spring, followed by autumn, while the winter and summer months experienced a slight precipitation increase independent of land use. In contrast to what was reported for Eastern Africa by Alter et al. (Nat Geosci 8:763–767. https://doi.org/10.1038/ngeo2514, 2015), the evaporation-enhanced colder land surface of the irrigated fields stabilizes the overlying atmosphere most effectively not in the summer months when precipitation is most abundant in Nebraska, but rather in early spring and fall. The observed precipitation suppression of irrigation only works at the regional scale; it does not apply to irrigated land that is not an integral part of the more-or-less continuous irrigated land region of east-central Nebraska.

Variation in Reproductive Timing for the Northern Long-Eared Myotis (Myotis septentrionalis) Across Nebraska

The northern long-eared myotis (Myotis septentrionalis), a federally threatened species, occurs in extreme northern, eastern, and southern Nebraska. These regions vary in climate due to geographic location, topography, and elevation. During a 1-week period in early July 2015, we surveyed bats across the state and observed striking variation in the reproductive status for M. septentrionalis. We examined whether or not growing degree days, an abiotic climatic factor used mainly for agricultural practices, was associated with this reproductive variation in a mammalian species. In early July, we captured only pregnant females in the Pine Ridge region of northwestern Nebraska, the region with the lowest number of growing degree days. In contrast, we captured both lactating females and flying young along the Republican River in south-central Nebraska near the border with Kansas, an area with a high, but intermediate number of growing degree days. Along the Missouri River, in extreme east-central Nebraska, along the border with Iowa, we documented lactating females with no evidence of volant young. This locality had the highest number of growing degree days. Phenotypic plasticity in timing of births for M. septentrionalis appears to be, in part, related to climatic differences across Nebraska, a relationship commonly observed for plants and invertebrates. Our study demonstrates that reproductive phenology can vary significantly across the distribution of a species and needs to be considered when making management decisions for imperiled species. Delayed reproduction in cooler regions of the species' range presents risks to reproductive female M. septentrionalis and their nonvolant offspring, even with current protective measures. In areas with short growing seasons, restrictions on the timing of tree-cutting should be expanded beyond 31 July in more northerly parts of the species' distribution, so as not to hinder reproductive success during the time when juvenile bats are unable to fly.

Dedicated Bioenergy Crops and Water Erosion.

Information on the water quality impact of perennial warm-season grasses (WSGs) when grown in marginal lands as dedicated energy crops is limited. We studied how WSGs affected runoff, sediment, and nutrient losses and related near-surface soil properties to those of no-till corn ( L.) on an eroded soil in southwestern Iowa and a center pivot corner in east-central Nebraska. The experiment at the eroded soil was established in 2012, and treatments included 'Liberty' switchgrass ( L.) and no-till continuous corn. The experiment at the pivot corner was established in 2013 with 'Liberty' switchgrass, 'Shawnee' switchgrass, low-diversity grass mixture, and corn. We simulated rainfall at 63.5 ± 2.8 mm h for 1 h to portray 5-yr return periods and measured water erosion in spring 2017. Time to runoff start and runoff depth did not differ between WSGs and corn. On the eroded soil, sediment and nutrient losses did not differ between treatments. At the pivot corner, sediment (0.71 vs. 0.15 Mg ha) and PO-P (0.037 vs. 0.006 kg ha) losses were five times higher in corn than in WSGs. Near-surface soil properties did not differ on the eroded soil, but at the pivot corner, wet aggregate stability was four times higher and residue cover was 34% higher in WSGs than in corn. Water-stable aggregates were negatively correlated with NO-N and PO-P losses. Overall, WSGs can improve water quality in marginally productive croplands, but their effectiveness appears to be site specific.

EXCEPTIONALLY WELL PRESERVED LATEST MIOCENE (HEMPHILLIAN) RODENT BURROWS FROM THE EASTERN GREAT PLAINS, UNITED STATES, AND A REVIEW OF THE BURROWS OF NORTH AMERICAN RODENTS

Dozens of well-preserved fossil burrow systems in upper Miocene sedimentary rocks of the Ogallala Group at a site in east-central Nebraska record rodent behavior and the subsurface ecology of grasslands just as the modern Great Plains was developing. These burrow systems include one to four entrance or exit tunnels, large underground nesting chambers at depths of several decimeters below ancient land surfaces, and incisor grooves on the walls. Tunnels average 89.8 mm in diameter, a value similar to the burrow diameters of multiple living North American rodents. Chambers vary in shape and typically exceed 500 mm in length; some attain 1000 mm in length. Living marmotine ground squirrels (tribe Marmotini) construct burrow systems of varying degrees of complexity, but they do not engage in shallow subsurface foraging. Extinct members of this group were the most likely excavators of the fossil burrows. In contrast, extant pocket gophers (family Geomyidae) and, presumably their fossil relatives, are obligate subterranean animals that produce linked deep and shallow burrow subsystems, the latter representing their chief foraging strategy. Our results raise issues regarding the relationships between the architecture of fossil rodent burrow systems and aspects of rodent behavior and life history, such as litter size, developmental rates, seasonal torpor, hibernation, and sociality in grasslands. An improved understanding of the burrowing behaviors of ancient rodents will highly complement the growing body of knowledge about the development of grasslands on Earth over time, but truly ichnological analyses of the burrows and burrowing behaviors of extant rodents are much needed.

Current Status of the Plains Pocket Mouse (Perognathus flavescens) in Eastern Nebraska

Distribution of the plains pocket mouse (Perognathus flavescens) overlaps tallgrass prairies in northeastern parts of the species' range in the central United States. Distribution and abundance of the plains pocket mouse appears negatively impacted by agricultural practices during the last century due to the scarcity of records throughout the region. In eastern Nebraska, few plains pocket mice have been captured and no published account exists in recent decades. We investigated the current status of P. f. perniger, the eastern subspecies in Nebraska, because of a paucity of information regarding this subspecies' natural history and suspected extirpation from the state. We captured 56 P f. perniger in 13 counties in northeastern and east-central Nebraska in 2008, including 10 counties lacking prior records. We also obtained data on its presence in extreme eastern Nebraska (Douglas and Lancaster counties) via a literature review and query for specimens in museums. Some individuals without darker-colored guard hairs represented the eastern limits of the western subspecies P. f. flavescens associated with the easternmost extent of the Sandhill Region of the state or other isolated sandy habitats. Across eastern Nebraska, many sites with captures of plains pocket mice appear to represent strongholds associated with isolated areas of friable, sandy soils. To date, presence of the species has not been detected in southeastern parts of the state. Conservation of habitats with sandy soils, along with implementation or continuance of disturbance regimes (i.e., grazing), will benefit this species and a number of other sand-adapted species in eastern Nebraska.

Determination of the anisotropy of an upper streambed layer in east-central Nebraska, USA

Information on the anisotropy of streambed hydraulic conductivity (K) is a necessity for analyses of water exchange and solute transport in the hyporheic zone. An approach is proposed for the determination of K, developed from existing in-situ permeameter test methods. The approach is based on determination of vertical and horizontal hydraulic conductivity of streambed sediments on-site and eliminates the effects of vertical flow in the hyporheic zone and stream-stage fluctuation, which normally influence in situ permeameter tests. The approach was applied to seven study sites on four tributaries of the Platte River in east-central Nebraska, USA. On-site permeameter tests conducted on about 172 streambed cores for the determination of vertical hydraulic conductivity (K v) and horizontal hydraulic conductivity (K h) at the study sites indicate that the study sites have relatively small anisotropic ratios, ranging from 0.74 to 2.40. The ratios of K h to K v from individual locations within a study site show greater variation than the anisotropic ratios from the mean or median K at each of the study sites.

Horizontal hydraulic conductivity of shallow streambed sediments and comparison with the grain‐size analysis results

AbstractStreambed horizontal hydraulic conductivity (Kh) has a substantial role in controlling exchanges between stream water and groundwater. We propose a new approach for determining Kh of the shallow streambed sediments. Undisturbed sediment samples were collected using tubes that were horizontally driven into streambeds. The sediment columns were analysed using a permeameter test (PT) on site. This new test approach minimizes uncertainties due to vertical flow in the vicinity of test tube and stream stage fluctuations in the computation of the Kh values. Ninety‐eight PTs using the new approach were conducted at eight sites in four tributaries of the Platte River, east‐central Nebraska, USA. The Kh values were compared with the nondirectional hydraulic conductivity values (Kg) determined from 12 empirical grain‐size analysis methods. The grain‐size analysis methods used the same sediment samples as Kh tests. Only two methods, the Terzaghi and Shepherd methods, yielded Kg values close to the Kh values. Although the Sauerbrei method produced a value relatively closer to Kh than other nine grain‐size analysis methods, the values from this method were not as reliable as the methods of Terzaghi and Shepherd due to the inconsistent fluctuation of the average estimates at each of the test sites. The Zunker, Zamarin, Hazen, Beyer, and Kozeny methods overestimated Kh, while the Slichter, US Bureau of Reclamation (USBR), Harleman, and Alyamani and Sen methods underestimated Kh. Any of these specific grain‐size methods might yield good estimates of streambed Kh at some sites, but give poor estimates at other sites, indicating that the relationship between Kg and Kh is significantly site dependent in our study. Copyright © 2011 John Wiley & Sons, Ltd.

Hispid Pocket Mouse (Chaetodipus hispidus) in East-Central and Northeastern Nebraska

The hispid pocket mouse (Chaetodipus hispidus) occurs throughout the Great Plains, mainly west of the Missouri River. In Nebraska, this species likely occurs throughout the state, but records of occurrence were lacking for east-central and northeastern counties. During a survey in 2008 for the plains pocket mouse (Perognathus flavescens) in eastern Nebraska, we documented C. hispidus in 10 new counties, including a modest range expansion into northeastern Nebraska. Many individuals were captured on moderately compact soils consisting of silt, but some also were captured on sandy and other friable soils. Most individuals were captured in areas containing some exposed ground, but this may reflect our trap placement for P. flavescens. Individuals from northeastern and east-central Nebraska best resembled C. h. spilotus from southeastern Nebraska, with black coloration suffused on the dorsum, head, and dorsal side of the tail; however, our individuals generally lacked the characteristic bright ochraceous coloration along lateral lines and on the dorsum. Limited evidence supports a recent expansion in distribution within the region.

Avian foraging patterns in crop field edges adjacent to woody habitat

As natural predators of pest insects, woodland birds provide biological pest suppression in crop fields adjacent to woody edges. Although many birds using these habitats forage widely, earlier studies have found that most foraging activity occurs within 50 m of the woody edge. The goals of this study were to determine the primary area of use, or functional edge, for birds foraging in crop fields adjacent to woody edges, and to evaluate their foraging distance patterns. During the summers of 2005 and 2006, avian foraging behavior was observed at 12 research sites in east central Nebraska that contained either a shelterbelt or woody riparian edge. At each site, perches were provided at 10 m intervals out from the edge and insect larvae were placed in feeders at random locations to simulate a pest insect food resource. Birds were recorded foraging in five distance categories out from the edge (0–10, 10–20, 20–30, 30–40, and 40–50 m). Seven species foraged primarily within 20 m of the edge (72% all observations; 79% without perch or feeder observations). Ten species foraged throughout the plots but six of these generally foraged more often (45% and 49%) and four less often (30% and 30%) within 20 m of the edge. The 13 species that tended to forage more often within 20 m of the edge, with 56% of their foraging overall in this area, also tended to forage farther when perch and feeder observations were included, indicating willingness to forage farther when food resources were available. Based on a repeated measures analysis of variance, foraging distances appeared to be greater at sites with soybean as the planted crop, although this apparent trend was significant for only some species. There was no clear difference in foraging distances outward from shelterbelt versus riparian sites. These results indicate that conservation efforts within the 20 m functional edge offer potential to enhance the sustainability of both birds and crops in agricultural landscapes.

Use of a mine by eastern pipistrelles (Perimyotis subflavus) in east central Nebraska

The eastern pipistrelle (Perimyotis subflavus) is relatively common and widespread throughout the eastern United States. In recent decades, the distribution of P. subflavus has expanded westward across the Great Plains, and little information exists on its natural history in this region. In east central Nebraska, we monitored the use of a mine by eastern pipistrelles for >1 year. A few males occupied the roost in summer, but during the period of hibernation (late September–early May), the mine was used by at least 30 individuals composed of both sexes. Most individuals first entered the mine during late September through mid-October and exited by mid-May, with numbers of individuals fluctuating throughout winter. In winter, most individuals roosted along outer passageways of the mine, but in other seasons individuals were scattered throughout the mine. Females had significantly greater body masses than males upon entering the mine in autumn and before exiting the mine in spring. Both sexes had significantly heavier body masses in autumn than in spring. Overall, 55% of individuals marked in spring returned in autumn. Males had a higher return rate (69%) than females (46%) over a single summer. Many aspects of the natural history of P. subflavus in Nebraska are similar to those reported from eastern but not from southern parts of its distribution.

FLOW PATHWAYS AND SEDIMENT TRAPPING IN A FIELD-SCALE VEGETATIVE FILTER

Vegetative filters (VF) are a best management practice installed in many areas to control sediment movement to water bodies. It is commonly assumed that runoff proceeds perpendicularly across a VF as sheet flow. However, there is little research information on natural pathways of water movement and performance of field-scale VF. The objectives of this study were: (1) to quantify the performance of a VF where the flow path is not controlled by artificial borders and flow path lengths are field-scale, and (2) to develop methods to detect and quantify overland flow convergence and divergence in a VF. Our hypothesis is that flow converges and diverges in field-scale VF and that flow pathways that define flow convergence and divergence areas can be predicted using high-resolution topography (i.e., maps). Overland flow and sediment mass flow were monitored in two 13 × 15 m subareas of a 13 × 225 m grass buffer located in Polk County in east-central Nebraska. Monitoring included a high-resolution survey to 3 cm resolution, dye tracer studies to identify flow pathways, and measurement of maximum flow depths at 51 points in each subarea. Despite relatively planar topography (a result of grading for surface irrigation), there were converging and diverging areas of overland flow in the buffer subareas. Convergence ratios ranged from -1.55 to 0.34. Predicted flow pathways using the high-resolution topography (i.e., map) closely followed actual flow paths. Overland flow was not uniformly distributed, and flow depths were not uniform across the subareas. Despite converging and diverging flow, the field-scale VF trapped approximately 80% of the incoming sediment.

Signature of magnetic enhancement in a loessic soil in Nebraska, United States of America

Our study of a loessic soil profile from east-central Nebraska shows that the A horizons of the modern soil are characterized by higher concentrations of fine-grained (<0.1 μm) magnetic minerals. This pedogenic magnetic component leads to higher values of concentration-dependent parameters, such as magnetic susceptibility ( χ), isothermal remanent magnetization (IRM) and anhysteretic remanent magnetization (ARM), combined with increases in frequency-dependent susceptibility ( χ fd) and ARM/IRM ratios. Hysteresis properties are relatively insensitive towards the presence of this pedogenic magnetic component. The magnetic properties of the soil profile are dominated by ferrimagnetic magnetite or maghemite. Analyses of “soft” IRM (sIRM) and “hard” IRM (hIRM), however, do show that approximately 80–90% of the remanence carrying magnetic component exists in the form of hematite or goethite and that the magnetically enhanced horizons are enriched in both ferri- and antiferromagnetic minerals. The pedogenic magnetic component is most likely caused by the conversion of paramagnetic, iron-bearing minerals to ferri- and antiferromagnetic minerals. Soil compaction, lessivage or decalcification cannot explain the observed magnetic soil properties. Magnetic analyses of loess-paleosol sequences from the midwestern United States may yield valuable information about regional variability of paleoclimate. Based on the fine-grained nature of the pedogenic magnetic component, we expect grain-size-dependent proxies (ARM, ARM/IRM, χ fd) to yield better paleoclimatic information than low-field magnetic susceptibility used in previous analyses.

Bean Leaf Beetle (Coleoptera: Chrysomelidae) Abundance in Soybean Fields Protected and Unprotected by Shelterbelts

The bean leaf beetle, Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), is a major insect pest of soybean in Nebraska and throughout much of the Midwest. This insect overwinters in the adult stage in litter in wooded areas such as shelterbelts. Historically, crop producers have been unsure of the merits of shelterbelts, especially if nearby crops are more likely to be infested by insect pests as a result. In this study, bean leaf beetle adults were sampled during the season by visually counting the number of beetles found on soybean plants early in the season and by sweep net sampling once plants were at the V4 stage (approximately 0.33 m tall). Sampling was done in 1997 and 1998 at the University of Nebraska Agricultural Research and Development Center in Saunders Co. in east-central Nebraska. Beetle counts were compared between shelterbelt-protected and -unprotected fields. In general, bean leaf beetles were more numerous in 1997 than in 1998, with abundance peaks occurring in late-July and early-September in both years. There were significant differences in bean leaf beetle counts from protected and unprotected fields on only three of the 11 and four of the 13 sampling dates in 1997 and 1998, respectively. On the sampling dates when significant differences were found, two of three in 1997 and three of four in 1998 had higher bean leaf beetle abundance in the protected soybean fields. The results of this study indicate a tendency for more bean leaf beetles in shelterbelt-protected soybean fields when differences are found, but beetle numbers were not significantly different between protected and unprotected fields on the majority of sample dates in the two years of this study. This study also reconfirms the presence of two generations of the bean leaf beetle in Nebraska.

New Species of Bretzia (Cervidae; Artiodactyla) from the Latest Pleistocene or Earliest Holocene of Nebraska and South Dakota

A new species of Bretzia is described from eastcentral Nebraska and southeastern South Dakota. Both localities in the Great Plains are latest Pleistocene or earliest Holocene in age. Bretzia is previously known only from Blancan-aged (Pliocene) sediments in Washington and California. New specimens of Bretzia described here extend both the temporal and geographic range of this rare cervid.

A Crop‐Specific Drought Index for Corn: II. Application in Drought Monitoring and Assessment

AbstractHow drought is perceived, and defined, determines the likely response of decision makers to a drought event. Since drought response is usually based on some type of assessment of the severity and duration of the event, a critical element of a drought response strategy lies in the incorporation of objective and reliable impact assessment techniques. However, a long‐standing problem in responding to past droughts has been the lack of reliable techniques for monitoring the drought event and assessing probable impacts. This paper describes a new method to reliably monitor and assess weather's probable impact on corn (Zea mays L.) yields, on a crop reporting district (CRD) level, any time during the growing season. The 1990 growing season was used to demonstrate the ability of the crop‐specific drought index (CSDI) to monitor and assess the condition of East Central Nebraska's corn crop every 10 days, starting 17 June, until a definitive projected CSDI value became established. A 3‐wk hot and dry spell (24 mm of rainfall during the 3‐wk period 28 June‐17 July) that immediately preceded silking resulted in a 17 July CSDI assessment, based on the climatological record of the CRD, that projected yields to be only 63% of the maximum yield previously attained in this CRD. However, a substantial rainfall event during the week of silking alleviated the stressful conditions, and by the beginning of the early grain fill period (blister stage), a 6 August CSDI assessment projected the final CSDI value to within 3% of the actual CSDI (projected and actual yields were 86 and 83%, respectively, of the maximum yield previously attained in Nebraska's East Central CRD). The results of this study demonstrate that the CSDI can monitor and assess weather's impact on corn yields on a CRD level.

An economic analysis of alternative cropping systems for east-central Nebraska

AbstractThirteen cropping systems were analyzed with respect to profitability and risk for east-central Nebraska. The systems were developed from 1) a four-year rotation containing a small grain, 2) two row crop rotations, 3) three continuous cropped alternatives, and 4) combinations of continuous cropped alternatives. Three systems were developed from the four-year rotation including two alternative treatments of inorganic chemicals as well as an organic alternative. Eight years of experimental yields, historical prices, and estimated costs were combined to estimate net returns for each of the thirteen systems. Risk was analyzed as net return variability using statistical characteristics of the net return series. The stability component of rotation risk was separated from the diversification component. We found rotations to have higher average net returns than continuously cropped systems. Different chemical treatments (including organic) had little impact on profitability. Rotations had lower return variability than most continuous crops. The organic treatment did not decrease variability of returns compared to other chemical systems.