Browsing by Subject "corn"
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Item Determining the role of plant-parasitic nematodes in the crop rotation yield effect, and the influence of crop rotation and nematicide application on the nematode community(2015-05) Grabau, ZaneIn the Midwestern United States, corn-soybean rotation is an essential agricultural practice to increase crop yield, often known as the rotation effect. Plant-parasitic nematodes, particularly soybean cyst nematode (SCN, Heterodera glycines) in soybean and Pratylenchus in corn, may contribute to the rotation effect and the nematode community is a sensitive indicator of changes in soil ecology. A long-term research site in Waseca, Minnesota was established in 1982 to study corn-soybean rotation. At the site, various corn-soybean crop sequences can be compared each year including corn and soybean in 1 to 5 years of monoculture, annual rotation of each crop, and continuous monoculture of each crop. Granular nematicides (terbufos or aldicarb) have been applied to half of each plot since 2010 to minimize nematode populations across crop sequences. If successful, the rotation yield effect could be compared with unaltered nematode populations and with minimal nematode populations to determine the role of nematodes in the rotation effect. For this thesis, crop yield and plant-parasitic nematode populations were measured from 2010-14 while the nematode community was assessed from 2013-14 at the long-term rotation research site. Specifically, the objectives of this research were to: (i) investigate the impact of crop sequences and nematicide application on plant-parasitic nematode populations and crop yield (Chapter 2), (ii) determine the role of plant-parasitic nematode populations in the corn-soybean rotation effect using nematicide application (Chapter 2), and (iii) study the impact of crop sequences and nematicide application on soil ecology based on the nematode community (Chapter 3). Research related to these objectives is reviewed in Chapter 1. SCN egg population densities significantly increased in soybean and decreased in corn—particularly in the initial 3 years of monoculture-- so populations were significantly greater in soybean than corn monoculture for most sequences (P ≤ 0.05, Fischer’s LSD). After two to three years of corn monoculture, SCN populations were below 200 eggs/100 cm3 soil, the proposed damage threshold guideline for SCN, in most seasons. Pratylenchus populations significantly decreased in soybean monoculture and increased in corn monoculture—particularly in the initial 3 years of monoculture-- leading to significantly greater Pratylenchus populations under corn than soybean monoculture for most sequences (P ≤ 0.05, Fischer’s LSD). Helicotylenchus population densities were similar among many crop sequences, but significantly greater in extended corn monoculture and smaller in extended soybean monoculture than most sequences (P ≤ 0.05, Fischer’s LSD). Xiphinema was present at the site, but population densities were small at an average of 8 nematodes/100 cm3 soil across plots and seasons. Corn yields decreased significantly in monoculture, particularly in the initial 3 years in monoculture (P ≤ 0.05, Fischer’s LSD). Soybean yields also decreased significantly in monoculture, often decreasing throughout the length of monoculture tested when comparing crop sequence treatments within single years (P ≤ 0.05, Fischer’s LSD). Aldicarb nematicide consistently significantly decreased Pratylenchus, Helicotylenchus, and Xiphinema populations but was inconsistent against SCN (P ≤ 0.05, ANOVA). Aldicarb nematicide consistently increased corn yield and decreased Pratylenchus and Helicotylenchus populations (P ≤ 0.05, ANOVA), suggesting these nematodes, particularly Pratylenchus, may have decreased corn yield. Aldicarb nematicide also significantly increased soybean yield in 2012 and 2013, but decreased SCN populations did not consistently correspond with increased soybean yield (P ≤ 0.05, ANOVA). While nematicide reduced nematode populations, there was still significant variation across crop sequences in most seasons (P ≤ 0.05, ANOVA), so nematicide application was not a successful method for determining the role of nematodes in the rotation effect in most seasons. However, the strong influence of crop sequences on SCN and Pratylenchus populations suggest nematodes have a role in the rotation effect. Nematicide application also impacted non-target nematodes and thus soil ecology with significantly decreased fungivore and bacterivore populations, diversity, and maturity; but significantly increased enrichment (P ≤ 0.05, ANOVA). The nematode community and soil ecology was significantly different in corn compared to soybean cropping systems and changed most during initial years of crop monoculture (P ≤ 0.05, Fischer’s LSD). Cropping systems in corn supported significantly greater fungivore populations, fungal decomposition pathways, more diversity, and a more mature ecosystem compared to soybean systems (P ≤ 0.05, Fischer’s LSD). Soybean systems supported significantly greater bacterivore populations and a more disturbed, enriched ecosystem (P ≤ 0.05, Fischer’s LSD). These differences between corn and soybean systems suggest nutrient mineralization by nematodes and other microorganisms may play a role in the benefits of crop rotation for plant growth.Item Effects of climate warming and nitrogen fixing bacterial inoculants on nitrous oxide emissions(2025) Bohnen, MichelleThe application of synthetic nitrogen (N) fertilizer to cropping systems leads to reactive N pollution including nitrous oxide (N2O) emissions. Nitrous oxide is an ozone-depleting substance and an important long-lived greenhouse gas. Potential mitigation solutions, including bacterial inoculants (BI) and enhanced efficiency fertilizers (EEF), have been proposed to reduce reactive N pollution. Nitrogen-fixing BIs supply the crop with N so that less synthetic N fertilizer must be added to maintain agricultural crop productivity. Enhanced efficiency fertilizers include controlled-release fertilizers and inhibitors to reduce N2O emissions and N leaching. Here, we examined the efficacy of using a nitrogen-fixing BI to lower N2O emissions over seven growing seasons across a broad range of fertilizer rates (FR). Further, we examined the efficacy of using a dual-inhibitor EEF to lower N2O emissions over four growing seasons and assessed if warmer soil temperature treatments (+ 2℃ reduced the EEF mitigation potential for climate change. The results indicated that the BI treatment effect alone did not have any significant effects on any of the environmental variables tested (e.g. N2O emissions, soil N concentrations, crop yield). Increasing FR increased cumulative N2O emissions, enhanced soil N concentrations, and decreased N use efficiency. Fertilizer rate had a polynomial relationship with leachate N, crop yield, and grain N. The interaction between FR and the BI treatment was significant for decreasing soil nitrate (NO3-) concentrations. This result indicated that soil NO3- concentrations increased at a faster rate per FR without a BI than when treated with a BI. Finally, N2O emissions increased linearly (0.012 kg N2O-N ha-1 per kg N ha-1 applied) with increasing FR from 81 to 404 kg N ha-1. The EEF experiments indicated that the growing season and temperature interaction effect was significant on cumulative N2O emissions and emission factors. The growing season effect was significant for most of the environmental variables that were tested. The conventional urea had significantly higher values of initial total soil N concentrations compared to the EEF. The conventional urea treatments and the effects of climate warming (i.e. heated soil temperatures) when using the EEF led to significantly less leachate N mass loss than the unheated EEF treatments. Additionally, the conventional urea treatments had lower leachate N concentrations than the unheated EEF treatments. The heated EEF and conventional urea treatments also had significantly lower plant N concentrations compared to the unheated EEF treatments. The results imply that there was better plant N acquisition in lower soil temperatures across growing seasons and between temperature treatments. Fertilizer rate had the dominant effect on cumulative N2O emissions, soil N concentrations, N use efficiency, crop yield, leachate N loss, and grain N uptake when compared to the effect of BIs. Soil warming has potential to reduce leachate N mass loss and plant N uptake. Using EEFs rather than conventional urea has potential to enhance leachate N loss as well as increase plant N uptake from improved synchronization between crop N demand and supply. Overall, N cycling was highly dependent on the mixed effects of FR, N source, and climate.Item Effects of Fertilizers and Stand on Corn and of Stand on Soil Moisture(Minnesota Agricultural Experiment Station, 1955-04) Shubeck, Fred E; Caldwell, A. C.Item Inheritance in Maize of Reaction to European Corn Borer and its Relationship to Certain Agronomic Characters(Minnesota Agricultural Experiment Station, 1958-08) Fleming, A. A.; Singh, Rameshwar; Hayes, H. K.; Pinnell, E. L.Item Liquid Swine Manure Applied via Drag Hose as a Sidedress Source for Corn Production(2020-03) Pfarr, ChristopherIn Minnesota, liquid swine manure (LSM) is commonly applied in the fall, which can increase the risk for nitrogen (N) to leave the root zone before next season’s crop can utilize it. Increased precipitation, as recently experienced in Minnesota, exacerbates this problem resulting in a growing interest for in-season nutrient application. Liquid swine manure applied via dragline hose was tested as a sidedress source for corn (Zea Mays L.) production compared to anhydrous ammonia (AA) and urea ammonium nitrate (UAN). Variables measured included corn stand counts, grain yield, grain moisture, and plant N uptake as well as soil compaction and soil in-organic N content through the growing season and post-season. Additionally, a small-plot dragline hose study was conducted comparing two different corn hybrids to examine what stage corn can be dragged before reducing stand counts and yield. When applied at similar plant-available N (PAN) rates, LSM produced comparable grain yields as AA and UAN despite lower soil in-organic N levels 12 days after application. Application of N sources at the vegetative (V4) growth stage did not reduce stand counts compared to the control, except for the LSM treatment in 2019 due to wet field conditions. Furthermore, the application of sidedress treatments did not increase soil compaction to critical levels that might impede root growth at the soil surface. In the small-plot study, corn grain yields were reduced at the V5 growth stage, and further reduced at the V6 growth stage, for both hybrids. Sidedressing LSM via a dragline hose system at or before the V4 growth stage provides producers in Minnesota an additional window of opportunity to apply their manure and is a viable nutrient source for sidedressing corn.Item Managing nitrogen from manure with a winter rye cover crop: Research dataset(2020-02-17) Everett, Leslie A.; Wilson, Melissa L.; Pepin, Randall J.; Coulter, Jeffrey A.; mlw@umn.edu; Wilson, MelissaThis data is from 19 on-farm studies in Minnesota to evaluate the use of cover crops to trap nutrients from fall manure applications and release them during the growing season for the following cash crop. It includes the amount of above-ground biomass that was produced by the cover crop (CC), soil nitrate in the top 24 inches of soil in plots with and without CC, and yields of the following cash crop in plots with and without CC. There is also data on CC and corn nitrogen uptake. This data was published in a peer-reviewed journal article and is now released.Item Managing the Rotation from Alfalfa to Corn(University of Minnesota Extension, 2015) Yost, Matt A.; Coulter, Jeffery A.; Russelle, Michael P.This bulletin describes management practices for alfalfa termination and the two subsequent corn crops that will help utilize the benefits of alfalfa.Item A Method for Farm Planning Under Uncertain Weather Conditions with Application to Corn-Soybean Farming in Southern Minnesota(Minnesota Agricultural Experiment Station, 1973) Boisvert, Richard N.; Jensen, Harald R.Item Natural-Air Corn Drying in the Upper Midwest(St. Paul, MN: University of Minnesota Extension Service, 1995) Wilcke, William F.; Morey, R. Vance"This publication is for corn producers, educators, consultants, and equipment dealers who are interested in natural-air corn drying in Minnesota and neighboring states. Answers to some common questions provide a description of natural-air drying, its advantages and disadvantages compared to other types of drying, equipment requirements, management recommendations, and expected energy use."(p.1)Item A Novel Mating Design to Optimize Genomic Selection Efficiency for Commercial Corn Breeding(2022-03) Sweet, PatrickIn many commercial corn (Zea. mays L.) breeding programs, lines are selected based only on general combining ability (GCA) during first-year trials. Selection for specific combining ability (SCA) is delayed until later trials, resulting in many unevaluated hybrid combinations. My objective was to determine whether a reciprocal testcross mating design enables simultaneous selection for GCA and SCA, while maintaining the same resources typical in first-year trials. Suppose B1 and B2 are Iowa Stiff Stalk Synthetic (BSSS) lines, whereas N1 and N2 are non-BSSS lines. In a reciprocal testcross design, progeny of B1 × B2 are testcrossed with N1 and N2, and progeny of N1 × N2 are testcrossed with B1 and B2. In 2019, grain yield and moisture of 1,642 hybrids from 10 BSSS and non-BSSS populations were measured at a median of three locations per hybrid across the upper Midwest. In 2020, a validation set consisting of 146 hybrids that were not tested in 2019 were evaluated at a median of five locations per hybrid. The GCA and SCA values were estimated using genomewide prediction with 11,000 SNP markers and the level of dominance was estimated using a subset of these markers. The sizes of training populations were kept constant, and the cross-year predictive ability of the reciprocal testcross design was compared with that of a standard, nonreciprocal design. Including SCA in the models marginally increased predictive abilities for reciprocal designs and the reciprocal designs produced higher predictive abilities than the nonreciprocal designs. The median level of dominance for grain yield was 1.08 indicating complete dominance. The results indicated that the reciprocal testcross mating design combined with genomic prediction could efficiently enable simultaneous selection for GCA and SCA earlier in a breeding pipeline.Item Solvita and Other Measures as Indicators of Soil N Availability in Minnesota Soils(2016-12) Tu, XinyiSolvita is a commercialized short-term C mineralization test reported to predict potentially mineralizable N (PMN) and thus useful as a basis for N recommendations. Our study compared Solvita results with other measures of available N and potential corn yield, including PMN measured in a laboratory aerobic incubation, soil organic matter, KCl-extractable N, and permanganate oxidizable C. We showed that a 50% water-filled pore space wetting method gave much more reproducible results than the fixed volume method previously recommended. Solvita proved to be a good indicator of mineralizable C and N, but not better than SOM, inorganic N, or POXC in MN soils. Solvita had stronger relationships with these soil measures in coarser textured soils (clay < 35%) and was related to corn yield in corn-corn rotations but not when preceding crops were alfalfa or soybean. At this point, we do not recommend its use as a tool for N recommendations.Item Some Important Insect Larvae Affecting Corn(University of Minnesota Extension, 1971) Baker, Norman; Hellenthal, RonaldItem A Study of the Sweet Corn Industry in the Midwest Farm Economy(Minnesota Agricultural Experiment Station, 1959-06) Andrews, Richard A.