Corn In Minnesota Research Articles

AGRICULTURAL BEST MANAGEMENT PRACTICE SENSITIVITY TO CHANGING AIR TEMPERATURE AND PRECIPITATION.

Agricultural best management practices (BMPs) reduce non-point source pollution from cropland. Goals for BMP adoption and expected pollutant load reductions are often specified in water quality management plans to protect and restore waterbodies; however, estimates of needed load reductions and pollutant removal performance of BMPs are generally based on historic climate. Increasing air temperatures and changes in precipitation patterns and intensity are anticipated throughout the U.S. over the 21st century. The effects of such changes on agricultural pollutant loads have been addressed by several authors, but how these changes will affect the performance of widely promoted BMPs has received limited attention. We use the Soil and Water Assessment Tool (SWAT) to investigate potential changes in the effectiveness of conservation tillage, no-till, vegetated filter strips, grassed waterways, nutrient management, winter cover crops, and drainage water management practices under potential future temperature and precipitation patterns. We simulate two agricultural watersheds in the Minnesota Corn Belt and the Georgia Coastal Plain with different hydro-climatic settings, under recent conditions (1950-2005) and multiple potential future mid-century (2030-2059) and late-century (2070-2099) climate scenarios. Results suggest future increases in agricultural source loads of sediment, nitrogen and phosphorous. Most BMPs continue to reduce loads, but removal efficiencies generally decline due to more intense runoff events, biological responses to changes in soil moisture and temperature, and exacerbated upland loading. The coupled effects of higher upland loading and reduced BMP efficiencies suggest that wider adoption, resizing, and/or combining practices may be needed in the future to meet water quality goals for agricultural lands.

Determining socially optimal rates of nitrogen fertilizer application

Effective management of nitrogen (N) fertilizer is central to enhancing agricultural productivity, while improving water and air quality and mitigating climate change. Quantifying “socially optimal” rates of N fertilizer (i.e. maximizing net benefits to society while minimizing social costs) is a key component of any regulatory or incentive program designed to better manage N application. Here, we estimate spatially-explicit socially optimal N fertilizer application rates for corn in Minnesota that account for uncertainty, both in valuation techniques and model parameters. We find that socially optimal rates of N fertilizer application are between 0 and 161 kg ha−1, whereas the private optimum is 165 kg ha−1. Choice of valuation methods shifts the spatial configuration and magnitude of the socially optimal N application rates illustrating the importance of valuation method and assumptions. Even after accounting for uncertainty in valuation methods, we find reducing rates of N fertilizer application offers significant opportunities to improve social welfare. By internalizing the social costs of nitrogen, net social benefits of N could increase by over $1100 ha−1, even while accounting for declines in agricultural yields.

Minnesota field population of western corn rootworm (Coleoptera: Chrysomelidae) shows incomplete resistance to Cry34Ab1/Cry35Ab1 and Cry3Bb1

AbstractIn the United States of America, the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is commonly managed with transgenic corn (Zea mays L.) expressing insecticidal proteins from the bacteria Bacillus thuringiensis Berliner (Bt). Colonies of this pest have been selected in the laboratory on each commercially available transformation event and several resistant field populations have also been identified; some field populations are also resistant. In this study, progeny of a western corn rootworm population collected from a Minnesota corn field planted to SmartStax® corn were evaluated for resistance to corn hybrids expressing Cry3Bb1 (event MON88017) or Cry34/35Ab1 (event DAS‐59122‐7) and to the individual constituent proteins in diet‐overlay bioassays. Results from these assays suggest that this population is resistant to Cry3Bb1 and is incompletely resistant to Cry34/35Ab1. In diet toxicity assays, larvae of the Minnesota (MN) population had resistance ratios of 4.71 and >13.22 for Cry34/35Ab1 and Cry3Bb1 proteins, respectively, compared with the control colonies. In all on‐plant assays, the relative survival of the MN population on the DAS‐59122‐7 and MON88017 hybrids was significantly greater than the control colonies. Larvae of the MN population had inhibited development when reared on DAS‐59122‐7 compared with larvae reared on the non‐Bt hybrid, indicating resistance was incomplete. Overall, these results document resistance to Cry3Bb1 and an incomplete resistance to Cry34/35Ab1 in a population of WCR from a SmartStax® performance problem field.

Survey of nitrogen fertilizer use on corn in Minnesota

A survey was conducted in the spring of 2010 to characterize the use of nitrogen (N) fertilizer on corn (Zea mays L.) by Minnesota farmers in the 2009 growing season. Detailed information on synthetic N fertilizer management practices was collected from interviews with 1496 farmers distributed across all of the corn growing regions in the state. The total amount of corn they grew represented 6.8% of the ha of corn harvested in Minnesota in 2009. This report summarizes data on: (1) N fertilizer rates, (2) major N sources (excluding manures), (3) application timing of the major N source, (4) use of nitrification inhibitors, additives, and specialty N fertilizer formulations, (5) fertilizer placement and incorporation practices, (6) use of starter fertilizer, split and sidedress applications, and other N sources such as ammonium phosphates, (7) N fertilization of irrigated corn, and (8) use of soil testing as a fertility management tool. Many of the survey results are reported as statewide averages, but where regional differences occurred the data are broken down and presented separately for different parts of the state. This survey provides the most comprehensive set of data on N fertilizer use on corn that has been collected in Minnesota. The information can be used to target research and education programs to improve N management for both production and environmental goals. The statewide average N fertilizer rate was 157kgNha−1. Variable rate application was used to apply N by 23% of farmers. About 59% of surveyed farmers applied the majority of their N fertilizer in the spring before planting, 32.5% made their main N application in the fall, and 9% sidedressed the majority of their N after corn emergence. Most farmers used anhydrous ammonia (46%) or urea (45%) as their major source of N fertilizer, while 6.5% used a liquid N formulation as their primary N source. Soil testing was used as a fertility management tool on 84% of the surveyed fields in the last 5years. Overall results indicate that N fertilizer use by Minnesota corn farmers is generally consistent with University of Minnesota Extension N management guidelines. Fertilizer N use could probably be improved by taking adequate N credit for previous soybean crops. In the South Central region of the state, fertilizer N recovery could potentially be improved by increased use of nitrification inhibitors with fall-applied anhydrous ammonia or by delaying anhydrous ammonia application until spring.

Minnesota Corn Breeding History: Department of Agronomy & Plant Genetics Centennial

A century of corn (Zea mays L.) breeding at Agronomy & Plant Genetics, University of Minnesota, developed Minnesota 13 cultivar (Minn13) that enlarged the U.S. Corn Belt and also developed 273 corn inbreds. Minn13 was widely grown in 15 northern and higher elevation states for 40 yr before hybrid corn. Minnesota inbreds were used in 30.6% of the seed for the 1975 U.S. corn crop: Minnesota A632 15.2%, A634 7.8%, A619 4.2%, W117 (1/2 Minn13) 1.8%, A635 0.9%, A554 0.6%, and A654 0.1%. Our main objective is to measure the contribution of Minnesota corn breeding to today's corn. We define today's corn as the 305 proprietary corn inbred lines registered by U.S. Plant Variety Protection or utility patent 2004 to 2008. Minnesota developed corn inbreds contributing most to today's corn are C49 (A9), A509, A556, B164, and A237. These corn inbreds were sources of earliness that formed the Pioneer Early Iodents (PEI) at Mankato, MN in the early 1960s. They average 1.1% of the genes and 137 (45%) of the descendents among today's corn. The Minn13 inbred line descendents contributing most to today's corn are DeKalb/Monsanto's (DKM) 3IIH6, PEI's PH207, PHG3BD2, Ohio Oh43, and Holden/Monsanto's (HFM) LH82. Minn13 descendents have maintained about 4% genetic contribution 1984 to 2008. Clustering pedigree based genetic distance of Minn13 derived progeny in today's corn showed three major pedigree groups: HFM's LH82, PEI, and DKM's Iodent. The latter two are Early Iodent germplasm.

Urea Decreases Nitrous Oxide Emissions Compared with Anhydrous Ammonia in a Minnesota Corn Cropping System

Quantifying N2O emissions from corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] fields under different fertilizer regimes is essential to developing national inventories of greenhouse gas emissions. The objective of this study was to compare N2O emissions in plots managed for more than 15 yr under continuous corn (C/C) vs. a corn–soybean (C/S) rotation that were fertilized during the corn phase with either anhydrous NH3 (AA) or urea (U). During three growing seasons, N2O emissions from corn following corn were nearly identical to corn following soybean. In both systems, however, N2O emissions with AA were twice the emissions with U. After accounting for N2O emissions during the soybean phase, it was estimated that a shift from C/S to C/C would result in an increase in annual emissions of 0.78 kg N ha−1 (equivalent to 0.11 Mg CO2–C ha−1) when AA was used, compared with only 0.21 kg N ha−1 (0.03 Mg CO2–C ha−1) with U. In light of trends toward increased use of U, these results suggest that fertilizer‐induced soil N2O emissions may decline in the future, at least per unit of applied N, although further study is needed in different soils and cropping systems. While soil CO2 emissions were 20% higher under C/C, crop residue from the prior year did not affect soil inorganic N or dissolved organic C during the subsequent season. We also compared different flux‐calculation schemes, including a new method for correcting chamber‐induced errors, and found that selection of a calculation method altered N2O emissions estimates by as much as 35%.

Optimizing <I>Helicoverpa zea</I> (Lepidoptera: Noctuidae) Insecticidal Efficacy in Minnesota Sweet Corn: A Logistic Regression to Assess Timing Parameters

Late-season plantings of sweet corn in Minnesota result in an abundant supply of silking corn, Zea mays L., throughout August to early September that is highly attractive to the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae). During a 10-yr period, 1997-2006, insecticide efficacy trials were conducted in late-planted sweet corn in Minnesota for management of H. zea. These data were used to develop a logistic regression model to identify the variables and interactions that most influenced efficacy (proportion control) of late-instar H. zea. The pyrethroid lambdacyhalothrin (0.028 kg [AI]/ha) is a commonly used insecticide in sweet corn and was therefore chosen for use in parameter evaluation. Three variables were found to be significant (alpha = 0.05), the percentage of plants silking at the time of the first insecticide application, the interval between the first and second insecticide applications, and the interval between the last insecticide application and harvest. Odds ratio estimates indicated that as the percentage of plants silking at the time of first application increased, control of H. zea increased. As the interval between the first and second insecticide application increased, control of H. zea decreased. Finally, as the interval between the last insecticide application and harvest increased, control of H. zea increased. An additional timing trial was conducted in 2007 by using lambda-cyhalothrin, to evaluate the impact of the percentage of plants silking at the first application. The results indicated no significant differences in efficacy against late-instar H. zea at 0, 50, 90, and 100% of plants silking at the first application (regimes of five or more sprays). The implications of these effects are discussed within the context of current integrated pest management programs for late-planted sweet corn in the upper midwestern United States.

Carbon and Nitrogen Storage are Greater under Biennial Tillage in a Minnesota Corn–Soybean Rotation

Few studies have examined the impacts of rotational tillage regimes on soil carbon (C) and nitrogen (N). We measured the C and N content of soils managed under corn (Zea mays L.)–soybean (Glycine max L.) rotation following 10 and 15 yr of treatments. A conventional tillage (CT) regime employing moldboard and chisel plowing in alternate years was compared with both continuous no‐till (NT) and biennial tillage (BT), which employed chisel plowing before soybean only. While masses of C and N in the upper 0.3 m under both BT and NT were higher than CT, only the BT treatment differed from CT when the entire sampled depth (0.6 m) was considered. Decreased C inputs, as indicated by reduced grain yields, may have limited C storage in the NT system. Thus, while more C was apparently retained under NT per unit of C input, some tillage appears necessary in this climate and cropping system to maximize C storage. Soil carbon dioxide (CO2) fluxes under NT were greater than CT during a drier than normal year, suggesting that C storage may also be partly constrained under NT due to wetter conditions that promote increased soil respiration. Increased temperature sensitivity of soil respiration with increasing soil moisture was also observed. These findings indicate that long‐term biennial chisel plowing for corn–soybean in the upper mid‐west USA can enhance C storage, reduce tillage‐related fuel costs, and maintain yields compared with more intensive annual tillage.

Predicted Impact of an Exotic Generalist Predator on Monarch Butterfly (Lepidoptera: Nymphalidae) Populations: A Quantitative Risk Assessment

The multicolored Asian lady beetle, Harmonia axyridis (Pallas), was recently identified as a potential hazard to monarch butterflies, Danaus plexippus (L.). A quantitative risk assessment for the potential impact of H. axyridis on D. plexippus in Minnesota corn and soybean fields was developed using risk analysis software. This assessment considered a potential worst-case scenario for the impact of H. axyridis on D. plexippus. Habitat-specific recruitment of D. plexippus eggs was determined empirically. Subsequently, simulated abundance of D. plexippus in each habitat was reduced by two classes of stage-specific mortality: predation by H. axyridis and causes other than H. axyridis. Predation was modeled as a function of D. plexippus exposure to H. axyridis, and predation rate of D. plexippus by H. axyridis. Exposure and subsequent risk varied considerably by habitat, with a low risk of H. axyridis adversely affecting D. plexippus populations developing in corn fields, but a moderate to high risk in soybean fields. Predicted rates of D. plexippus mortality attributable to H. axyridis were greater in soybean compared to corn fields, possibly due to the numerical response of H. axyridis to soybean aphid, Aphis glycines Matsumura. This study demonstrates that H. axyridis has the potential to have a strong adverse impact on D. plexippus populations. However, the likelihood of occurrence for this worst-case scenario remains uncertain. To evaluate the landscape-level risk of H. axyridis impacting D. plexippus, further data on recruitment of D. plexippus in other habitats and exposure estimates specific to additional habitats are needed.

Comparative study of three expeller process soybean meals in diets for lactating dairy cows (2002)

Forty-eight primiparous Holstein cows were used in two simultaneous 3x3 Latin squares with 28-day periods to evaluate expeller soybean meal from three sources. Six pens containing eight cows each were utilized. Cows were pen fed diets formulated in accordance with NRC (2001) recommendations and based on the assumption that the three sources of soybean meal were nutritionally identical. Diets contained on a dry matter basis, 24.3% chopped alfalfa hay, 9.3% field processed corn silage, 9.2% whole fuzzy cottonseed, 19.2% wet corn gluten feed (Minnesota Corn Processors, Inc., Columbus, NE), and 38% grain mix (70.2% dry rolled corn grain, 18.44% expeller soybean meal, 2.15% wet molasses, 3.47% Menhaden fish meal, and 5.74% min/vit premix). The sources of expeller soybean meal were Grain States Soya, Inc., West Point, NE; NCKP, LLC., Washington, KS; and Bruning Grain and Feed, Bruning, NE. All cows averaged 77 lbs. of milk and consumed approximately 55 lbs. of dry matter daily. Dry matter intake averaged 3.9% of body weight and their production efficiency (ECM/DMI) was 1.45. No differences due; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

European Corn Borer Management in Field Corn: A Survey of Perceptions and Practices in Iowa and Minnesota

The European corn borer (Ostrinia nubilalis Hubner) is a major pest of field corn (Zea mays L.) in the midwestern states. In 1991, an outbreak of this insect caused yield losses as high as 32.6 bu/acre in Iowa and averaged 14 bu/acre in Minnesota. Following this pest outbreak, a questionnaire was developed to: (i) assess how farmers and agribusiness professionals perceive the crop production risks posed by European corn borer, and (ii) explore how these perceptions are reflected in management options they use or recommend. Farmers and agribusiness professionals completed 851 surveys. The survey results provided insights into yield loss perceptions, management tactics used, and research needs for European corn borer management. Economic yield losses caused by European corn borers during the first and second generations, respectively, were thought to occur only by 65 to 69% of farmers, 78 to 81% of ag-chemical professionals, 84 to 89% of crop consultants, and 68 to 70% of educator/agronomists. Respondents that perceived economic losses caused by European corn borers thought that the average loss was 15.3 to 16.6 bu/acre during the first generation and 15.2 to 18.1 bu/acre during the second generation. Although two-thirds of the farmers perceived the European corn borer as a serious pest, only 35% had ever scouted their fields and used economic thresholds, and only 28% had ever used an insecticide to control the pest. Farmers' primary and secondary options for managing the European corn borer or reducing yield losses were to harvest the fields early before ears drop onto the ground (63.4%) and to plant hybrids with known resistance (39.0%), respectively. In contrast, scouting and using economic thresholds was the primary recommendation from ag-chemical professionals (68.3%), crop consultants (88.5%), and educator/agronomists (54.0%). The second most common recommendation was using an insecticide by ag-chemical professionals (57.9%) and educator/agronomists (41.4%), whereas crop consultants were more likely to suggest early harvest to prevent ear droppage (73.8%). The survey results suggest that many farmers don't manage European corn borer because of historic inaction, hidden yield losses, reluctance to scout, logistical burnout, capital doubts, cultural competition, insecticide concerns, and a failure to recognize the problem. The results also suggest a strong need to educate farmers and agribusiness professionals regarding biology, crop damage, and management options for the European corn borer.

Control of Fall Armyworm in Pre-Tassel Sweet Corn in Minnesota, 1995

Abstract This test was conducted at the University of Minnesota Rosemount Agricultural Experiment Station, Rosemount, MN. ‘Jubilee’ sweet corn was planted 12 Jun in plots consisting of a single 30 ft row on 30 inch centers. Each plot was separated by one untreated border row on each side and 7 ft alleys at each end. Treatments were arranged in a RCB design with four replications. FAW egg masses, obtained from USDA-ARS at Mississippi State, MS, were placed in the whorl of each plant 28 Jul. A single application of each treatment was made 5 Aug. Applications were made using a CO2-pressurized back-pack sprayer with one nozzle per row or a hand shaker to evenly distribute granular materials. The sprayer was calibrated to apply 30 gpa at 35 psi. Average temperature for all applications was 79°F. By 5 Aug, most FAW larvae were late 2nd to early 3rd instars, reflecting a 4 day delay in optimum (planned) treatment timing due to inclement weather. Treatments were evaluated 23 Aug by randomly selecting 25 ears per plot (100 per treatment) and recording the number of ears with late-instar FAW larvae and/or feeding damage.

The Value of Pest Information in a Dynamic Setting: The Case of Weed Control

AbstractThe value of weed scouting information for soil‐applied and post‐emergence weed management is estimated using a dynamic, whole‐farm, stochastic simulation model. The model simulates outcomes of four expected utility functions from management strategies using three levels of weed information. Results from a representative Minnesota corn and soybean farm indicate high value of weed seedling counts (for post‐emergence control) but relatively low value of weed seed counts (for soil‐applied control). While herbicide use is often reduced under information based management, this is not always the case.

Late-Season Insect Control on Sweet Corn in Minnesota, 1989

Abstract This test was conducted on the University of Minnesota Agricultural Experiment Station at Rosemount in corn planted 18 Jun. Two-row plots were 25 ft long with one untreated border row between each plot and 4 ft borders at the end of each plot. Treatments were replicated 4 times in a randomized complete block design. A backpack CO2 sprayer with one flat fan (LF-3-80, 50-mesh) nozzle/row, delivering 20 gal/acre at 40 psi, was used to treat each row of the plots from tassel to ear. First fresh silks were observed 17 Aug and treatments were applied 21, 28 Aug and 5 Sep. Plots were artificially infested with about 21 neonate ECB larvae/plant on 24 Aug. All plots were hand harvested and evaluated 9 Sep by randomly selecting 15 ears/row (30/plot), husking the ears and checking for ECB and CEW larvae.

Mycotoxins and Fusarium spp. associated with infected ears of corn in Minnesota.

Five Fusarium species were isolated from the grain of dent corn (Zea mays) selected from 20 of 32 damaged fields in 10 counties in Minnesota on the basis of hyphal growth visible on kernels in the field. Three mycotoxins were identified in the infected ears: zearalenone, deoxynivalenol, and 15-acetyl-deoxynivalenol. This is the first report of the presence of 15-acetyl-deoxynivalenol on corn ears in the field prior to harvest and in combination with deoxynivalenol and zearalenone. Ninety-nine cultures were selected from colonies growing from kernels on an agar medium; 30% of the cultures were F. graminearum, 23% were F. subglutinans, 20% were F. moniliforme, 14% were F. oxysporum, and 12% were F. proliferatum.

Long‐range aphid transport hypothesis for maize dwarf mosaic virus: history and distribution in Minnesota, USA

SUMMARYIn 1977 a sudden and dramatic epidemic of maize dwarf mosaic virus (MDMV) struck commercial fields of sweet corn in Minnesota causing multi‐million dollar losses. The epidemic was unusual in that MDMV historically had been confined to the southern United States and Ohio River Valley with only occasional occurrences reported from states bordering Canada. An extensive 5‐yr study of MDMV in Minnesota revealed a low incidence of MDMV from 1978 ‐ 81, and commercial fields badly infected in 1977 were not again infected. No evidence of wild host plants was found, neither was seed transmission in maize considered to be important, and MDMV strain ratios changed from year to year as did the distribution of infected fields. Concomitant studies on aphid retention revealed that MDMV could be retained by aphid vectors for more than 19 h, and that the 1977 epidemic was associated with a weather pattern that could be linked to potential aphid transport from the southern Great Plains of North America. All circumstantial evidence led to a long‐distance aphid transport hypothesis. This may be worth considering whenever unexpected epidemics of aphid‐transmitted non‐persistent viruses occur in regions where the particular virus is not endemic, and may also explain the widespread distribution of certain aphid‐transmitted non‐persistent viruses.

Underground bulk storage of shelled corn in Minnesota

Shelled corn with a mean moisture content of 15.7 ± 0.7% was placed in two types of underground and aboveground bins: one constructed of flexible polyolefin and the other, a modified, metal hog feeder. Temperatures in the bins were monitored over a nine-month period, and two layer-by-layer autopsies on the underground bins were conducted at six months and nine months. Aboveground bins experienced either total loss due to fungal problems or serious insect infestations, whereas the underground bins remained free of detectable live insects and exhibited fungal growth associated only with flaws in bin construction (that is, in sample ports designed for withdrawal of grain samples during storage).

Occurrence and Pathogenicity of Fusarium proliferatum on Corn in Minnesota

Occurrence and Pathogenicity of Fusarium proliferatum on Corn in Minnesota

Fifty Years of Minnesota Corn Production: Sources of Yield Increase1

AbstractCorn (Zea mays L.) yields in Minnesota have increased from the 2,010 kg/ha yield level of the pre‐1930's to the current 6,290 kg/ha average. This increased yield can he attributed to a series of technological, cultural, and management practices adopted by farmers. My objective is to atlempt an analysis of the magnitude of the changes and the relative contributions to grain yield each practice has made over the 50‐year time period. Only simple linear responses were estimated. No attempt has been made to evaluate the nature nor the magnitude of the interactions among the various management practices.The change from open‐pollinated to hybrid corn combined with the estimated 36.5 kg/ha/year genetic gain has produced 58% of the yield increase. Although each kilogram of applied commercial N has been estimated to increase yields by 18.9 kg of grain per kg for 47% of the gain in yield, the effects of less manure, and reduced N from mineralized organic matter actually produces a net N effect of 19%. Improved weed control by the use of herbicides on 93% of the hectarage has increased yields 23%.Plant densities have increased by 19,130 plantdha contributing 47.4 kg/ha/1,000 plants for a total of 21% of the gain. Better soil drainage, fall plowing, and herbicides have permitted planting 10 days earlier for an average gain of 36.4 kg/ha/day and a total of 8% of the net increase. Drilling corn rather than hill dropping has contributed 8% and fall plowing has contributed 5% to current yields. Row spacing has decreased from 107 to 90 cm for a gain of 10.2 kg/ha/cm or 4% of the gain.Rotation changes have had no net effect on N balance with increases in soybean [Glycine max (L.) Merr.] offsetting decreases in forage legume hectarage. However, there has been a negative effect of more hectares of corn following corn resulting in 3% loss from corn rootworm (Diabrotica spp.) and 7% loss due to the interference effect of corn following corn. Corn borer (Ostrinia nubilalis Hubner) became a problem in the 1940's and has reduced yield potential an average of 5%. Soil erosion has reduced yield potentials 8% over the 50 years. Other negative and unaccounted factors reduce the potential yields by 23%.

Chocolate Spot of Corn in Minnesota

Chocolate Spot of Corn in Minnesota