Other Plant Sciences Commons^™

Does Cover Crop Grazing Damage Soils And Reduce Crop Yields?, Humberto Blanco-Canqui, Mary E. Drewnoski, Jim C. Macdonald, Daren Redfearn, Jay Parsons, Gary W. Lesoing, Tyler Williams

Department of Agronomy and Horticulture: Faculty Publications

Cover crop (CC) grazing can be a potential strategy to support livestock and crop production while enhancing soil ecosystem services, but research on this potential multi-functionality of CCs is limited. We assessed 3-yr cereal rye (Secale cereale L.) CC grazing impacts on soil compaction, structure, water infiltration, fertility, and crop yields on an on-farm irrigated strip-till continuous corn (Zea mays L.) silage experiment on a sandy loam with <1% slope in west-central Nebraska. Treatments were: (a) non-grazed CC, (b) grazed CC, and (c) no CC. Across the 3 yr, cattle grazed CCs at 5.9 AUM ha−1 with grazing occurring over a 4-mo period during winter and/or spring, depending on the year. We measured soil properties within 5 d after grazing ended in spring before tilling and plant- ing corn. Cattle grazing resulted in a 92% decrease of CC biomass, compared with non-grazed CCs. Grazing did not affect soil penetration resistance (com- paction parameter), bulk density, aggregate stability, pH, and concentration of organic matter and nutrients except in the 2nd yr where it reduced cumulative infiltration by 80% and increased penetration resistance from 1.23 to 1.72 MPa but such increase was below root growth thresholds (<2 MPa). Cover crop grazing had no negative effect on corn silage yields although data were variable. Overall, CC grazing for 3 yr had small and variable effects on soils and crop yields, indi- cating that it can be a management option to support livestock production but more long-term data from different tillage and cropping systems, and climates are needed to further understand CC grazing implications.

A Systematic Review Of Durum Wheat: Enhancing Production Systems By Exploring Genotype, Environment, And Management (G × E × M) Synergies, Brian L. Beres, Elham Rahmani, John M. Clarke, Patricio Grassini, Curtis J. Pozniak, Cameron Guy Robinson Geddes, Kenton D. Porker, William E. May, Joel Ransom

Department of Agronomy and Horticulture: Faculty Publications

According to the UN-FAO, agricultural production must increase by 50% by 2050 to meet global demand for food. This goal can be accomplished, in part, by the development of improved cultivars coupled with modern best management practices. Overall, wheat production on farms will have to increase significantly to meet future demand, and in the face of a changing climate that poses risk to even current rates of production. Durum wheat [Triticum turgidum L. ssp. durum (Desf.)] is used largely for pasta, couscous and bulgur production. Durum producers face a range of factors spanning abiotic (frost damage, drought, and sprouting) and …

Training For Specialists Vs. Education For Agroecologists, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

I admit to being a slow learner. Graduate school training in agronomy at the University of California, Davis and in plant breeding at Cornell University provided me with top-quality opportunities to acquire the tools for crop improvement, plus the contacts to join professionals at the International Center for Tropical Agriculture in Colombia. As a young scientist dedicated to building on successes of the Green Revolution, I was convinced that genetic changes would solve global hunger. This had been amply demonstrated with the yield increases of wheat in Mexico and India, and with rice in Southeast Asia. Should this success not …

Validation Of Predictive Empirical Weed Emergence Models Of Abutilon Theophrasti Medik Based On Intercontinental Data, Valle Egea-Cobrero, Kevin Bradley, Isabel M. Calha, Adam S. Davis, Jose Dorado, Frank Forcella, John L. Lindquist, Christy L. Sprague, Jose L. Gonzalez-Andujar

Department of Agronomy and Horticulture: Faculty Publications

Good weed management relies on the proper timing of weed control practices in relation to weed emergence dynamics. Therefore, the development of models that predict the timing of emergence may help provide growers with tools to make better weed management decisions. The aim of this study was to validate and compare two previously published predictive empirical thermal time models of the emergence of Abutilon theophrasti growing in maize with data sets from the USA and Europe, and test the hypothesis that a robust and general weed emergence model can be developed for this species. Previously developed Weibull and Logistic models …

Quantifying On‐Farm Nitrous Oxide Emission Reductions In Food Supply Chains, A.J. Eagle, E. Mclellan, E.M. Brawner, M.H. Chantigny, Eric A. Davidson, J.B. Dickey, Bruce A. Linquist, T.M. Maaz, D.E. Pelster, Cameron M. Pittelkow, C. Van Kessel, T.J. Vyn, K. G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Reducing nitrous oxide (N2O) emissions from agriculture is critical to limiting future global warming. In response, a growing number of food retailers and manufacturers have committed to reducing N2O emissions from their vast networks of farmer suppliers by providing technical assistance and financial incentives. A key challenge for such companies is demonstrating that their efforts are leading to meaningful progress toward their climate mitigation commitments. We show that a simplified version of soil surface nitrogen (N) balance—or partial N balance—the difference between N inputs to and outputs

from a farm field (fertilizer N minus crop N), is a robust indicator …

Cover Crops And Weed Suppression In The U.S. Midwest: A Meta-Analysis And Modeling Study, Virginia Nicholas, Rafael Martinez-Feria, David Weisberger, Sarah Carlson, B. Basso, Andrea Basche

Department of Agronomy and Horticulture: Faculty Publications

In addition to soil health and conservation benefits, cover crops (CCs) may offer weed control in the midwestern United States, but individual studies report vary- ing effects. We conducted a meta-analysis of studies measuring weed biomass (WBIO) or density (WDEN) in paired CC and no-cover treatments in corn (Zea mays L.)–soybean [Glycine max (L.) Merr] rotations in the U.S. Midwest. Fifteen studies provided 123 paired comparisons of WBIO and 119 of WDEN. Only grass CCs significantly reduced WBIO, while no CC reduced WDEN. We found no evidence CC management factors (e.g., termination method) directly affected out- comes. Our dataset showed …

Solar Dimming Decreased Maize Yield Potential On The North China Plain, Qingfeng Meng, Baohua Liu, Haishun Yang, Xinping Chen

Department of Agronomy and Horticulture: Faculty Publications

Solar dimming has been increasing in rapidly developing regions (China and India) and threatening food security. Although previous studies have summarized the ef- fects of climate change-associated increases in temperature on agriculture, few have examined the effects due to solar dimming. Here, we analyzed the effects of solar dimming on maize on the North China Plain (NCP). It is reported that solar dimming intensified and maize yield potential decreased since the 1960s. The total decrease in solar radiation for the whole maize growing season of this period was 17%, and solar dimming explained 87% of the decrease in yield potential. …

Management Strategies For Early- And Late-Planted Soybean In The North-Central United States, Emma G. Matcham, Spyridon Mourtzinis, Shawn P. Colney, Juan I. Rattalino Edreira, Patricio Grassini, Adam C. Roth, Shaun N. Casteel, Igancio A. Ciampitti, Hans J. Kandel, Peter M. Kyveryga, Mark A. Licht, Daren S. Mueller, Emerson Nafziger, Seth Naeve, Jordan D. Stanley, Michael J. Staton, Laura E. Lindsey

Department of Agronomy and Horticulture: Faculty Publications

It is widely recognized that planting soybean [Glycine max (L.) Merr.] early is critical to maximizing yield, but the influence of changing management factors when soybean planting is delayed is not well understood. The objectives of this research were to (a) identify management decisions that increase seed yield in either early- or late-planted soybean scenarios, and (b) estimate the maximum break-even price of each management factor identified to influence soybean seed yield in early- or late-planted soybean. Producer data on seed yield and management decisions were collected from 5682 fields planted with soybean during 2014−2016 and grouped into 10 technology …

Calibrating Soybean Parameters In Jules 5.0 From The Us-Ne2/3 Fluxnet Sites And The Soyface-O3 Experiment, Felix Leung, Karina Williams, Stephen Sitch, Amos P.K. Tai, Andy Wiltshire, Jemma Gornall, Elizabeth A. Ainsworth, Timothy J. Arkebauer, David Scoby

Department of Agronomy and Horticulture: Faculty Publications

Abstract. Tropospheric ozone (O3) is the third most important anthropogenic greenhouse gas. O3 is detrimental to plant productivity, and it has a significant impact on crop yield. Currently, the Joint UK Land Environment Simula- tor (JULES) land surface model includes a representation of global crops (JULES-crop) but does not have crop-specific O3 damage parameters and applies default C3 grass O3 pa- rameters for soybean that underestimate O3 damage. Physiological parameters for O3 damage in soybean in JULES- crop were calibrated against leaf gas-exchange measure- ments from the Soybean Free Air Concentration Enrichment (SoyFACE) with O3 experiment in Illinois, USA. Other …

Insufficient Nitrogen Supply From Symbiotic Fixation Reduces Seasonal Crop Growth And Nitrogen Mobilization To Seed In Highly Productive Soybean Crops, Nicolas Cafaro La Menza, Juan Pablo Monzon, John L. Lindquist, Timothy J. Arkebauer, Johannes M.H. Knops, Murray Unkovich, James E. Specht, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen (N) supply can limit the yields of soybean [Glycine max (L.) Merr.] in highly productive environments. To explore the physiological mechanisms underlying this limitation, seasonal changes in N dynamics, aboveground dry matter (ADM) accumula- tion, leaf area index (LAI) and fraction of absorbed radiation (fAPAR) were compared in crops relying only on biological N2 fixation and available soil N (zero-N treatment) versus crops receiving N fertilizer (full-N treatment). Experiments were conducted in seven high-yield environments without water limitation, where crops received optimal management. In the zero-N treatment, biological N2 fixation was not sufficient to meet the N demand of …

Seeding Rates And Productivity Of Broadcast Interseeded Cover Crops, Katja Koehler-Cole, Roger W. Elmore

Department of Agronomy and Horticulture: Faculty Publications

Broadcast interseeding cover crops into corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) instead of drill-planting after harvest extends the cover crop season and improves productivity, but establishment can be insufficient. Our objectives were to find broadcast seeding rates that result in maximum spring biomass and N uptake. We tested cereal rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth) in south-central and eastern Nebraska in 2016–2017 and 2017–2018. Seeding rates for rye were 341, 512, and 682 seeds·m−2, and 119, 178, and 238 seeds·m−2 for vetch. We broadcast in late September and terminated by early May. …

Woody Plant Encroachment And The Sustainability Of Priority Conservation Areas, Dillon Fogarty, Caleb P. Roberts, Daniel R. Uden, Victoria M. Donovan, Craig R. Allen, David E. Naugle, Matthew O. Jones, Brady W. Allred, Dirac L. Twidwell Jr

Department of Agronomy and Horticulture: Faculty Publications

Woody encroachment is a global driver of grassland loss and management to counteract encroachment represents one of the most expensive conservation practices implemented in grasslands. Yet, outcomes of these practices are often unknown at large scales and this constrains practitioner’s ability to advance conservation. Here, we use new monitoring data to evaluate outcomes of grassland conservation on woody encroachment for Nebraska’s State Wildlife Action Plan, a statewide effort that targets management in Biologically Unique Landscapes (BULs) to conserve the state’s natural communities. We tracked woody cover trajectories for BULs and compared BUL trajectories with those in non-priority landscapes (non-BULs) to …

Is Allelopathy From Winter Cover Crops Affecting Row Crops?, Katja Koehler-Cole, Sydney Everhart, Yan Gu, Christopher A. Proctor, Margarita Marroquin-Guzman, Daren Redfearn, Roger W. Elmore

Department of Agronomy and Horticulture: Faculty Publications

Cover crops (CC) have been explored in corn (Zea mays L.), cotton (Gossypium hirsutum L.), soybean [Glycine max (L.) Merr.], and wheat (Triticum aestivum L.) systems for their allelopathic potential to control weeds. However, allelopathic compounds may negatively affect these row crops by reducing germination, emergence, and grain yields. We reviewed studies that document allelopathic effects of CC on subsequent row crops in field and laboratory settings. We summarize the influence of CC management, including biomass production, planting and termination timing on allelochemical quantity. Our review found few studies documenting allelopathic effects of CC on row …

Winter Wheat Residue Impact On Soil Water Storage And Subsequent Corn Yield, Luana Machado Simão, Amanda Easterly, Greg Kruger, Cody Creech

Department of Agronomy and Horticulture: Faculty Publications

Standing winter wheat (Triticum aestivum L.) residue can capture snow, reduce soil erosion and water evaporation, and increase crop yields in semi-arid environments. Solid-stemmed winter wheat (SSWW) varieties may remain standing longer in the field; however, SSWW consistently yields less than conventional hollow-stemmed winter wheat (HSWW). This research investigates if the negative economic impact of yield loss of SSWW may be overcome by increasing the subsequent corn (Zea mays L.) yield due to increased snow capture and soil moisture. The experiment covered two cycles of a wheat–corn–fallow rotation in two separate fields between 2016 and 2019 near Sidney, NE. …

Improvement Of Smallholder Farming Systems In Africa, Charles S. Wortmann, Tilahun Amede, Mateete Bekunda, Keziah Ndung’U-Magiroi, Patricia Masikati, Sieglinde S. Snapp, Zachary P. Stewart, Mark Westgate, Zacarie Zida, Charles E. Kome

Department of Agronomy and Horticulture: Faculty Publications

This forum paper provides a synthesis and discussion of 14 categories of lessons learned from experiences for achieving farm-level impact with smallholder farm- ers in Africa. These lessons were reported in a symposium hosted by the Agron- omy in Africa community of the American Society of Agronomy. The lessons, listed in order of frequency of reporting, were the need to: have adequate infras- tructure and services; enable spontaneous adoption; have multi-disciplinary and institutional collaboration; build on previous adoption of good agronomic practices (GAP); have farmer participation in research; encourage and learn from smallholder adaptations; make GAP promotion demand-driven; allow GAP …

Soil Aggregation As Affected By Application Of Diverse Organic Materials, Maman Garba, Charles S. Wortmann, Humberto Blanco-Canqui

Department of Agronomy and Horticulture: Faculty Publications

Application of organic materials can amend soil for improved water infiltration and reduced erodibility with effects varying with soil properties and the organic amendment type and rate. The effects of four livestock manures, three municipal biosolids, and one industrial by-product on dry and wet soil aggregate stability were evaluated at six sites in Nebraska. The amendments had similar C/N ratios but the biosolids had relatively high concentrations of lignin and cellulose. Soil organic matter (SOM) ranged from 21 to 65 g kg−1 and soils were silty clay loam, silt loam, or loamy sand. Soil was sampled for the 0- to …

Strategic Switchgrass (Panicum Virgatum) Production Within Row Cropping Systems: Regional-Scale Assessment Of Soil Erosion Loss And Water Runoff Impacts, Enheng Wang, R. M. Cruse, Bharat Sharma-Acharya, Daryl E. Herzmann, Brian K. Gelder, David E. James, Dennis C. Flanagan, Humberto Blanco-Canqui, Robert B. Mitchell, David Laird

Department of Agronomy and Horticulture: Faculty Publications

A strong need exists for tools to assess the efficacy of conservation practices across large regions supporting informed policy decisions that may lead to better soil and water conservation while optimizing agricultural production options. Perennial warm-season grasses (WSGs) such as switchgrass (Panicum virgatum), can be grown on marginally productive and/or environmentally sensitive lands to meet growing bioenergy demands while reducing water runoff and soil erosion compared to current row crop systems. Quantifying the soil and water conservation effects of WSG when strategically placed on the landscape would help support decisions favoring both economic and environmental benefits. We used the Daily …

Soybean Nodule-Associated Non-Rhizobial Bacteria Inhibit Plant Pathogens And Induce Growth Promotion In Tomato, Serkan Tokgöz, Dilip K. Lakshman, Mahmoud H. Ghozlan, Hasan Pinar, Daniel P. Roberts, Amitava Mitra

Department of Agronomy and Horticulture: Faculty Publications

The root nodules are a unique environment formed on legume roots through a highly specific symbiotic relationship between leguminous plants and nodule-inducing bacteria. Previously, Rhizobia were presumed to be the only group of bacteria residing within nodules. However, recent studies discovered diverse groups of bacteria within the legume nodules. In this report soybean nodule-associated bacteria were studied in an effort to identify beneficial bacteria for plant disease control and growth promotion. Analysis of surface-sterilized single nodules showed bacterial diversity of the nodule microbiome. Five hundred non-rhizobial colonies from 10 nodules, 50 colonies per nodule, were tested individually against the tomato …

Foliar Micronutrient Application For High-Yield Maize, Zachary P. Stewart, Ellen T. Paparozzi, Charles S. Wortmann, Prakash Kumar Jha, Charles A. Shapiro

Department of Agronomy and Horticulture: Faculty Publications

Nebraska soils are generally micronutrient sufficient. However, critical levels for current yields have not been validated. From 2013 to 2015, 26 on-farm paired comparison strip-trials were conducted across Nebraska to test the effect of foliar-applied micronutrients on maize (Zea mays L.) yield and foliar nutrient concentrations. Treatments were applied from V6 to V14 at sites with 10.9 to 16.4 Mg ha−1 yield. Soils ranged from silty clays to fine sands. Soil micronutrient availability and tissue concentrations were all above critical levels for deficiency. Significant grain yield increases were few. Micronutrient concentrations for leaf growth that occurred after foliar applications were …

Estimating Economic Minimums Of Mowing, Fertilizing, And Irrigating Turfgrass, Douglas J. Soldat, James T. Brosnan, Ambika Chandra, Roch E. Gaussoin, Alec Kowalewski, Bernd Leinauer, Frank S. Rossi, John C. Stier, J. Bryan Unruh

Department of Agronomy and Horticulture: Faculty Publications

The public health crisis and economic recession caused by the COVID-19 pandemic have forced turfgrass industry professionals to re-evaluate standard practices. Minimum costs required to fertilize, irrigate, and mow turfgrasses can be roughly estimated using climate data, turfgrass physiology information, and resource costs. Although the actual minimum costs vary situationally and regionally, mowing golf putting greens optimally requires about US$34 per acre per month, whereas other turfgrass areas cost less than US$11 per acre per growing month. Fertilizer applications to turfgrass cost US$22 or less per acre per growing month. Irrigation costs (water and electricity for pumping) vary widely, with …