Clay Center Research Articles

Control of glyphosate-resistant giant ragweed (Ambrosia trifida L.) with premix of iodosulfuron/thiencarbazone applied alone or in tank mixtures in no-till corn (Zea mays L.)

The objectives of this study were to evaluate the efficacy of a new premix of iodosulfuron (6%)/thiencarbazone (45%) applied alone or tank-mixed with 2,4-D, dicamba, glyphosate, or metribuzin in the fall and (or) early spring followed by preemergence (PRE) and postemergence (POST) herbicide applications for control of glyphosate-resistant giant ragweed and their effect on corn yield. Field experiments were conducted in no-till corn fields infested with glyphosate-resistant giant ragweed (20–30 plants m−2) near Clay Center and McCool Junction, NE, in 2013 and 2014, respectively. A premix of iodosulfuron/thiencarbazone applied alone or in split applications in the fall and early spring controlled glyphosate-resistant giant ragweed <60% and resulted in a density of 14 giant ragweed plants m−2, which was comparable to the untreated control at 28 d after early spring treatment (DAEST). Metribuzin or 2,4-D applied alone resulted in <75% giant ragweed control at 28 DAEST; however, 2,4-D or dicamba tank-mixed with iodosulfuron/thiencarbazone provided ≥92% control. Treatments including 2,4-D or dicamba led to 85%–98% reduction in giant ragweed biomass at 28 DAEST. A follow-up application of a premix of isoxaflutole/thiencarbazone tank-mixed with atrazine applied PRE was not effective, although a POST application of tembotrione + atrazine resulted in >91% control at 28 d after postemergence treatment. The premix applied alone did not provide effective control of giant ragweed in corn primarily because lack of residual activity.

409 Late Summer Planted Oat-Brassica Forage Quality and Change during Winter.

The change in nutritive value of late summer planted oats and brassicas during the winter is not well documented. Over a two-year study, samples were collected at fifteen random locations within four 12 ha paddocks in early November, December, and January near Clay Center, Nebraska. Oats (Avena sativa) were clipped at ground level and purple top turnip (Brassica rapa) and daikon oilseed radish (Raphanus sativus) tops were separated from their roots. These forages were planted on September 8th and August 25th in yr 1 and 2, respectively. The year by date by species interaction was not significant (P > 0.20) for either in vitro organic matter digestibility (IVOMD) or CP. There were year by species and date by species interactions (P < 0.01) for IVOMD, with oats having lesser IVOMD in yr 2 (69%) than yr 1 (80%), but IVOMD of turnip (87%) and radish top (86%) not differing (P ≥ 0.25) among year within species. In each month, the turnip and radish tops did not differ (P ≥ 0.09) in digestibility and were more (P < 0.01) digestible than oats. Within species, the digestibility in November and December did not differ (P ≥ 0.17) but decreased (P < 0.01) from December to January. However, the digestibility of oats appeared to decline more (9% units) than turnip and radish tops (5% units). For CP, the date by species interaction was not significant (P = 0.26), but there were (P < 0.01) year by date and year by species interactions. The CP content of oats (21% yr 1 and 10% yr 2) was lesser (P < 0.01) than radish and turnip top in both years. The CP of the radish (29%) and turnip (28%) top did not differ (P = 0.27) in yr 1, but in yr 2 the CP of radish top (24%) was greater (P < 0.01) than turnip top (20%). The CP content decreased (P < 0.01) 2 to 3% units from November to December in both years, but in yr 1, CP content increased (P < 0.01) 4% units from December to January, whereas, CP continued to decrease (P < 0.01) 2% units from December to January in yr 2. Although the forage changed color from green to brown after hard freezes in November, the forage retained much of its nutritive value through January.

Comparison of a premix of atrazine, bicyclopyrone, mesotrione, and S-metolachlor with other preemergence herbicides for weed control and corn yield in no-tillage and reduced-tillage production systems in Nebraska, USA

A premix of atrazine, bicyclopyrone, mesotrione, and S-metolachlor (ABMS) has recently been registered for broad-spectrum weed control in corn (Zea mays L.) in the USA. The objectives of this study were to compare the efficacy of ABMS applied preemergence (PRE) with other commonly used PRE herbicides for weed control, corn injury, and yield in no-tillage (no-till) and reduced-tillage (reduced-till) corn production systems, and to determine the biologically effective doses of ABMS for controlling Palmer amaranth (Amaranthus palmeri S. Wats.) in field conditions. Field experiments were conducted in 2015 and 2016 at South Central Agricultural Laboratory, Clay Center, Nebraska, USA. ABMS applied at the labeled dose (2.89 kg ai ha−1) resulted in 92–99% Palmer amaranth control in both tillage systems. A similar level of Palmer amaranth control (86–99%) was observed with mesotrione plus rimsulfuron in the no-till system; however, the control was higher with ABMS than with other premixes in the reduced-till system at 42 days after treatment (DAT) and at harvest. Applications of ABMS at 2.89 kg ai ha−1 provided 99 and 81% control of velvetleaf (Abutilon theophrasti Medik.) and foxtail (Setaria spp.), respectively, in the no-till system at 28 DAT, whereas control was ≥93% in the reduced-till system. ABMS applied at 2.89 kg ai ha−1 resulted in 3% corn injury at 14 DAT regardless of the tillage system, whereas 15% corn injury was observed with acetochlor plus clopyralid plus flumetsulam, and dimethenamid-P plus saflufenacil in the reduced-till. ABMS or mesotrione plus rimsulfuron at labeled doses resulted in 16.0–16.3 t ha−1 corn yield, comparable to the weed-free control (16.4 t ha−1). The biologically effective doses of ABMS to provide 90% control (ED90) of Palmer amaranth at 42 DAT were 2.44 and 2.81 kg ai ha−1 in no-till and reduced-till systems, respectively. The efficacy of ABMS for broadleaf weed control and early-season grass weed control, and corn yield was the same or sometimes better than most of the PRE herbicides tested in this study; therefore, ABMS can be considered as an additional option for management of problem weeds, including Palmer amaranth in corn in the USA.

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Impact of irrigation and nitrogen fertilizer rate on soil water trends and maize evapotranspiration during the vegetative and reproductive periods

Field research was conducted in 2011 and 2012 at the University of Nebraska-Lincoln South Central Agricultural Laboratory located near Clay Center, NE to evaluate maize actual evapotranspiration (ETa) during the vegetative and reproductive growth periods for 0, 84, 140, 196, and 252kgha−1 nitrogen (N) fertilizer treatments under full irrigation (FIT), limited irrigation (75% of FIT), and rainfed settings. Daily ETa values were greatest during the early reproductive period (silking to blister growth stages) with average values of 3.62, 5.18, and 5.91mmd−1 in 2011 and 4.37, 5.92, and 6.12mmd−1 in 2012 for rainfed, 75% FIT, and FIT, respectively. Maize ETa during the vegetative period was not significantly impacted by N fertilizer rate in 2011 (P0.05=0.2357) or 2012 (P0.05=0.6341). Whereas, reproductive period ETa for FIT and 75% FIT for the pooled years significantly increased with N fertilizer rate with slopes of 0.20 and 0.17, respectively. The rainfed regression slopes were not statistically different from zero in 2012 (P0.05=0.1467) or pooled years (P0.05=0.0505). The increase in reproductive ETa with N fertilizer and irrigation resulted in a positive grain yield response with slopes of 0.021, 0.048, and 0.104 Mg ha−1mm−1 for the rainfed, 75% FIT, and FIT settings, respectively.

Genetic variance and covariance and breed differences for feed intake and average daily gain to improve feed efficiency in growing cattle.

Feed costs are a major economic expense in finishing and developing cattle; however, collection of feed intake data is costly. Examining relationships among measures of growth and intake, including breed differences, could facilitate selection for efficient cattle. Objectives of this study were to estimate genetic parameters for growth and intake traits and compare indices for feed efficiency to accelerate selection response. On-test ADFI and on-test ADG (TESTADG) and postweaning ADG (PWADG) records for 5,606 finishing steers and growing heifers were collected at the U.S. Meat Animal Research Center in Clay Center, NE. On-test ADFI and ADG data were recorded over testing periods that ranged from 62 to 148 d. Individual quadratic regressions were fitted for BW on time, and TESTADG was predicted from the resulting equations. We included PWADG in the model to improve estimates of growth and intake parameters; PWADG was derived by dividing gain from weaning weight to yearling weight by the number of days between the weights. Genetic parameters were estimated using multiple-trait REML animal models with TESTADG, ADFI, and PWADG for both sexes as dependent variables. Fixed contemporary groups were cohorts of calves simultaneously tested, and covariates included age on test, age of dam, direct and maternal heterosis, and breed composition. Genetic correlations (SE) between steer TESTADG and ADFI, PWADG and ADFI, and TESTADG and PWADG were 0.33 (0.10), 0.59 (0.06), and 0.50 (0.09), respectively, and corresponding estimates for heifers were 0.66 (0.073), 0.77 (0.05), and 0.88 (0.05), respectively. Indices combining EBV for ADFI with EBV for ADG were developed and evaluated. Greater improvement in feed efficiency can be expected using an unrestricted index versus a restricted index. Heterosis significantly affected each trait contributing to greater ADFI and TESTADG. Breed additive effects were estimated for ADFI, TESTADG, and the efficiency indices.

Economic Return versus Crop Water Productivity of Maize for Various Nitrogen Rates under Full Irrigation, Limited Irrigation, and Rainfed Settings in South Central Nebraska

AbstractField research was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory (SCAL) located near Clay Center, NE, in the growing seasons of 2011 to 2014. A partial economic analysis was conducted for maize (Zea mays L.) at nitrogen (N) fertilizer treatments of 0, 84, 140, 196, and 252 kg ha−1 under full irrigation (FIT), limited irrigation (75% FIT), and rainfed settings for all growing seasons and then compared to crop water productivity (CWP) measured as crop water use efficiency (CWUE) and irrigation water use efficiency (IWUE). Nitrogen fertilizer increased CWUE and IWUE in all growing seasons. The CWUE values ranged from 0.90 to 2.81 kg m−3 and the IWUE values ranged from −1.01 to 3.24 kg m−3. Operational costs and net income varied among treatments and across years. Irrigation and N fertilizer rate had an interacting effect (P0.05<0.05) on both gross and net income in 2011, 2012, and 2013. Net income was maximized under rainfed settings with a N fertilizer rate...

Evaluation of Foliar Applied Pyrethroid Insecticides for Control of Adult Corn Rootworm in Corn, 2015: Table 1

The efficacy of foliar-applied insecticides was evaluated against adult corn rootworm (CRW) populations in field corn near Clay Center, NE, during 2015. In continuous corn environments high populations of CRW adults feed on corn silks and may interfere with pollination, reducing grain yield. Information is needed on the efficacy of foliar insecticides against adult CRW in reproductive stage corn. Adult CRW populations consisted of >95% WCR and <5% SCR. Experimental design was an RCB with four replicates. Plot …

Evaluation of Foliar-Applied Insecticides for Control of Adult Corn Rootworm in Corn, 2015C: Table 1

The efficacy of foliar applied insecticides was evaluated against adult corn rootworm (CRW) populations in field corn near Clay Center, NE during 2015. Adult CRW populations consisted of > 95% WCR and <5% SCR. Experimental design was a RCB with four replicates. Plot size was 8 rows × 30 ft length with 30-inch row spacing. ‘Pioneer P0157R’ corn hybrid was planted on 28 May …

Evaluation of Near Isoline Corn Rootworm Traited and Refuge Corn Hybrids in Combination With Soil Insecticides at Planting for Larval Corn Rootworm Control, 2015: Table 1

Near isoline corn rootworm (CRW), traited and refuge corn hybrids in combination with soil insecticides were evaluated for effectiveness of larval CRW control near Clay Center, NE during 2015. Trial site was late-planted corn and pumpkins (insecticide free) during 2014. Experimental design was a RCB with four replicates. Plot size was 4 rows × ∼70 ft length with 30-inch row spacing. Soil type was a Crete silt loam. ‘NK N68B-3122’ (contains AgriSure 3122 insect and herbicide traits), ‘NK N68B-3000GT’ (contains AgriSure 3000GT insect and herbicide traits), and ‘NK N68B-GT’ (contains AgriSure …

Evaluation of Foliar Applied Insecticides for Control of Adult Corn Rootworm in Corn, 2015: Table 1

The efficacy of foliar applied insecticides was evaluated against adult corn rootworm (CRW) populations in field corn near Clay Center, NE during 2015. Adult CRW populations consisted of > 95% WCR and <5% SCR. Experimental design was a RCB with four replicates. Plot size was 8 rows × 30 ft length with 30-inch row spacing. ‘Pioneer P0157R’ corn hybrid was planted on 28 May …

Evaluation of Corn Rootworm Traited and Refuge Hybrids in Combination With Aztec 4.67G Insecticide at Planting for Control of Larval Corn Rootworm, 2015: Table 1

Single corn rootworm (CRW) traited and refuge hybrids in combination with Aztec 4.67G insecticide at planting were evaluated for effectiveness of larval CRW control near Clay Center, NE during 2015. The trial site was late-planted corn and pumpkins (insecticide free) during 2014. The experimental design was a RCB with four replicates. Plot size was 4 rows × ∼70 ft length with 30-inch row spacing. Soil type was a Crete silt loam. ‘DeKalb DKC62-95’ (contains Roundup Ready 2 herbicide trait [refuge hybrid]), ‘DeKalb DKC62-97RIB’ (contains 90% GENVT3PRIB traited seed and 10% refuge seed), ‘Pioneer P1395AM1’ (contains 90% Herculex XTRA traited seed and 10% Herculex I traited seed), and ‘NK N68B-3111’ …

Reference (Potential) Evapotranspiration. II: Frequency Distribution in Humid, Subhumid, Arid, Semiarid, and Mediterranean-Type Climates

AbstractWhile evapotranspiration (ET) has been a subject of research for decades, there is insufficient data, analyses and information on frequency (probability) values and distribution of this important variable for various climatic regions. Frequency distributions of grass-reference and alfalfa-reference (potential) evapotranspiration (ETo and ETr) were quantified and analyzed using long-term measured climate datasets for five locations in the United States that have significantly different climatic characteristics [Mediterranean-type climate, Davis, CA (ETo); arid, Phoenix, AZ (ETo); humid/subtropical, Gainesville, FL (ETo); a transition zone between subhumid and semiarid climate, Clay Center, NE (ETr); and a semiarid climate, Scottsbluff, NE (ETr)]. Two Nebraska locations presented higher variability of ETref among all locations because of their highly turbulent climatic characteristics with abrupt changes in wind speed, humidity and air temperature. At Davis, the peak ETo month is July with an averag...

Reference (Potential) Evapotranspiration. I: Comparison of Temperature, Radiation, and Combination-Based Energy Balance Equations in Humid, Subhumid, Arid, Semiarid, and Mediterranean-Type Climates

AbstractGrass-reference (potential) evapotranspiration (ETo) is often used in climate change studies to evaluate potential impacts of climate change on hydrologic balances and vegetation response. In this process, empirical temperature or radiation-based empirical equations are often used because of a lack of long-term climate data to solve the combination-based energy balance equations, but this may result in false determinations of trends and magnitudes of water use. To quantify potential differences associated with using such empirical models with respect to the FAO56 Penman-Monteith method (PM), various ETo models were evaluated in five locations that have significantly different climatic characteristics [subhumid, semiarid, arid, humid (subtropical), and Mediterranean-type] in Nebraska (Clay Center and Scottsbluff), Florida (Gainesville), Arizona (Phoenix), and California (Davis). In general, the performance of most methods not only varied with climatic conditions, but also with the time step used (i...

Evaluation of Stacked and Single Rootworm-Traited and Refuge Corn Hybrids in Combination With Soil Insecticides at Planting for Larval Corn Rootworm Control, 2014: Table 1

Corn hybrid family isolines possessing stacked rootworm traits, a single rootworm trait, or refuge traits, in combination with soil insecticides, were evaluated for effectiveness of larval CRW control near Clay Center, NE, during 2014. Trial site was in late-planted corn and pumpkins (insecticide free) during 2013. Experimental design was an RCB with three replicates. Plot size was 4 rows by 75 ft in length with 30-inch row spacing. Soil type was a Crete silt loam. ‘Golden Harvest G11U58-3122’ (3122, contains Agrisure RW and Herculex RW rootworm traits), ‘Golden Harvest G11U58-3111’ (3111, contains Agrisure RW rootworm trait), and ‘Golden Harvest G11U58-GT’ (GT, contains no rootworm …

Resistivity Arrays as an Early Warning System for Monitoring Runoff Holding Ponds

Monitoring wells are installed to intercept contaminants inadvertently discharged from inground structures designed to retain salt-affected wastewaters; however, several difficulties with collection and data interpretation limit their effectiveness. Therefore, improved monitoring methods are needed. The objective of this study was to evaluate the effectiveness of resistivity array technology as an early warning system to monitor for unintended basin discharge. Subsurface resistivity arrays were installed at two Nebraska sites: a beef cattle feedyard located at the U.S. Meat Animal Research Center, Clay Center, Nebraska (FyA) and a commercial cattle feeding operation (FyB). Monitoring well data did not identify any unintended discharge events during the study period. However, the resistivity array (RA) system detected a discharge event that was localized in the non-saturated zone adjacent to the pond at FyB within one day following a precipitation event. Monitoring the unsaturated portion allows the RA system a capacity beyond traditional monitoring wells, which can only intercept discharge carried in groundwater. Also, the RA system effectively measured a larger area (i.e., a virtual curtain) compared to the point measure typical of monitoring wells. Therefore, RA technology provides broader coverage and is more tolerant to placement issues for intercepting discharge. Finally, the capacity to automate the RA system provides a means to continuously monitor unintended subsurface discharge from runoff holding ponds. This continuous monitoring system is more likely to detect discharge events than the bi-annual sampling typically required for monitoring wells. Automatic and continuous monitoring provides feedyard operators options to better manage environmental impacts associated with runoff holding ponds.

Evaluation of SmartStax-Traited and Refuge Corn Hybrids in Combination with Soil Insecticides at Planting for Larval Corn Rootworm Control, 2014: Table 1

SmartStax traited and refuge corn hybrids in combination with soil insecticides were evaluated for effectiveness for larval corn rootworm (CRW) control near Clay Center, NE during 2015. The trial site was late-planted corn and pumpkins (insecticide free) during 2014. Experimental design was a RCB with four replicates. Plot size was 4 rows × ∼150 ft length with 30-inch row spacing. Soil type was a Crete silt loam. ‘DeKalb DKC62-77 RIB’ (contains GENSSRIB [SmartStax] insect and herbicide traits) and ‘DeKalb DKC62-98RIB’ (contains GENVT2PRIB [refuge] insect and herbicide traits) corn hybrids were planted on 30 Apr with a two-row JD 7100 Maximerge planter with finger pickup seed units. A …

Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean

Jhala, A. J., Malik, M. S. and Willis, J. B. 2015. Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean. Can. J. Plant Sci. 95: 973–981. Acetochlor, an acetamide herbicide, has been used for many years for weed control in several crops, including soybean. Micro-encapsulated acetochlor has been recently registered for preplant (PP), pre-emergence (PRE), and post-emergence (POST) application in soybean in the United States. Information is not available regarding the sequential application of acetochlor for weed control and soybean tolerance. The objectives of this research were to determine the effect of application timing of micro-encapsulated acetochlor applied in tank-mixture with glyphosate in single or sequential applications for weed control in glyphosate-resistant soybean, and to determine its impact on soybean injury and yields. Field experiments were conducted at Clay Center, Nebraska, in 2012 and 2013, and at Waverly, Nebraska, in 2013. Acetochlor tank-mixed with glyphosate applied alone PP, PRE, or tank-mixed with flumioxazin, fomesafen, or sulfentrazone plus chlorimuron provided 99% control of common waterhemp, green foxtail, and velvetleaf at 15 d after planting (DAP); however, control declined to ≤40% at 100 DAP. Acetochlor tank-mixed with glyphosate applied PRE followed by early POST (V2 to V3 stage of soybean) or late POST (V4 to V5 stage) resulted in ≥90% control of common waterhemp and green foxtail, reduced weed density to ≤2 plants m−2 and biomass to ≤12 g m−2, and resulted in soybean yields &gt;3775 kg ha−1. The sequential applications of glyphosate plus acetochlor applied PP followed by early POST or late POST resulted in equivalent weed control to the best herbicide combinations included in this study and soybean yield equivalent to the weed free control. Injury to soybean was &lt;10% in each of the treatments evaluated. Micro-encapsulated acetochlor can be a good option for soybean growers for controlling grasses and small-seeded broadleaf weeds if applied in a PRE followed by POST herbicide program in tank-mixture with herbicides of other modes of action.

Comparison of Glufosinate-Based Herbicide Programs for Broad-Spectrum Weed Control in Glufosinate-Resistant Soybean

Because of the increasing number of glyphosate-resistant weeds, alternate herbicide-resistant crops and herbicides with different modes of action are required to protect crop yield. Glufosinate is a broad-spectrum POST herbicide for weed control in glufosinate-resistant crops, including soybean. The objective of this study was to compare herbicide programs with glufosinate applied singly at late-POST (LPOST) or sequentially at early POST (EPOST) followed by (fb) LPOST applications and PRE herbicides fb EPOST/LPOST glufosinate alone or tank-mixed with acetochlor, pyroxasulfone, orS-metolachlor in glufosinate-resistant soybean. A field experiment was conducted at the South Central Agriculture Laboratory in Clay Center, NE, in 2012 and 2013. Glufosinate applied in a single LPOST or sequential EPOST fb LPOST application controlled common lambsquarters, common waterhemp, eastern black nightshade, green foxtail, large crabgrass, and velvetleaf ≤ 82% and resulted in a weed density of 6 to 10 plants m−2by the end of the season. Flumioxazin-, saflufenacil-, or sulfentrazone-based premixes provided 84 to 99% control of broadleaf and grass weeds tested in this study at 15 d after PRE application and a subsequent LPOST application of glufosinate alone controlled broadleaf and grass weeds 69 to 93% at harvest, depending on the herbicide program and weed species being investigated. The PRE application of sulfentrazone plus metribuzin fb EPOST glufosinate tank-mixed with acetochlor, pyroxasulfone, orS-metolachlor controlled the tested broadleaf and grass weeds ≥ 90%, reduced density to ≤ 2 plants m−2, and reduced weed biomass to ≤ 10 g m−2and produced soybean yields of ≥ 4,450 and 3,040 kg ha−1in 2012 and 2013, respectively. Soybean injury was 0 to 20% from PRE or POST herbicides, or both and was inconsistent, but transient, during the 2-yr study, and it did not affect soybean yield. Sulfentrazone plus metribuzin applied PRE fb glufosinate EPOST tank-mixed with acetochlor, pyroxasulfone, orS-metolachlor provided the highest level of weed control throughout the growing season and increased soybean yield compared with a single LPOST or a sequential EPOST fb LPOST glufosinate application. Additionally, these herbicide programs provide four distinct mechanisms of action that constitute an effective weed-resistance management strategy in glufosinate-resistant soybean.

Performance Analysis of Capacitance and Electrical Resistance-Type Soil Moisture Sensors in a Silt Loam Soil

The performance of the Irrometer 200SS Watermark granular matrix sensor (WM), John Deere Field Connect (JD-v2) probe, and Delta-T PR1-capacitance (PR1-C) probe were evaluated against a Troxler 4302 neutron gauge (NG) for in-season field volumetric water content (θv) measurements at two soil depths in a Hastings silt loam soil at the University of Nebraska-Lincoln/Institute of Agriculture and Natural Resources South Central Agricultural Laboratory (SCAL) near Clay Center, Nebraska. The performances of the sensors were investigated over three years (2011-2013) under various water, nutrient, and crop management practices. The WM sensors performed best when using a field-calibrated soil water retention curve (SWRC) [root mean square difference (RMSD) = 0.024 m3 m-3] as compared to a SWRC developed from a pedotransfer function (RMSD = 0.070 m3 m-3). The WM sensors using a previously developed SWRC for the experimental field resulted in RMSD values less than 0.05 m3 m-3 when compared to the NG-measured θv at all depths and years. The JD-v2 probes underestimated θv in the dry range and overestimated θv in the wet range, which resulted in regression slopes and intercepts for the 0.30 and 1.0 m soil depths that were significantly different from unity (i.e., 1.0) and zero (p0.05