Field research 2008

Kansas Agricultural Experiment Station Research Reports, Jun 2017

Kansas State University. Agricultural Experiment Station and Cooperative Extension Service

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Field research 2008

Kansas Agricultural Experiment Station Research Reports Follow this and additional works at: http://newprairiepress.org/kaesrr Part of the Agronomy and Crop Sciences Commons Recommended Citation Kansas State University. Agricultural Experiment Station and Cooperative Extension Service (2009) "Field research 2008," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 6. https://doi.org/10.4148/2378-5977.3378 - Thi s report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 2009 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. K-State Research and Extension is an equal opportunity provider and employer. Creative Commons License Thi s work is licensed under a Creative Commons Attribution 4.0 License. Thi s Research Report article is available in Kansas Agricultural Experiment Station Research Reports: http://newprairiepress.org/ kaesrr/vol0/iss6/1 FIELD RESEARCH 2008 Report of Progress 1011 Kansas State University Agricultural Experiment Station and Cooperative Extension Service Agronomy Field Research 2008 Table of Contents Harvey County Experiment Field Harvey County Experiment Field Introduction.........................................................................................................................HC-1 Soil Description ..................................................................................................................HC-1 2006-2007 Weather Information.........................................................................................HC-1 No-Till Crop Rotation Effects on Wheat, Corn, Grain Sorghum, Soybean and Sunflower ......................................................................................................HC-3 Effects of Late-Maturing Soybean and Sunn Hemp Summer Cover Crops and Nitrogen Rate in a No-Till Wheat-Grain Sorghum Rotation ..........................HC-10 Effects of Planting Date, Hybrid Maturity, and Plant Population in No-Till Corn ................HC-15 Evaluation of Mesotrione (Lumax) for Crop Safety in Grain Sorghum ................................HC-19 Herbicides for Cheat Control in Winter Wheat ......................................................................HC-24 Experiment Field Personnel Supporting Agencies and Companies Mark M. Claassen, Agronomist-in-Charge Lowell Stucky, Plant Science Technician II Kevin Duerksen, Plant Science Technician I Dow AgroSciences Fluid Fertilizer Foundation Monsanto Pioneer Rohm and Haas Sorghum Partners, Inc. Triumph Seed Co. Syngenta HARVEY COUNTY EXPERIMENT FIELD Research at the Harvey County Experiment Field deals with many aspects of dryland crop production on soils of the Central Loess Plains and central Outwash Plains of central and south central Kansas and is designed to directly benefit agricultural industries in the area. The focus is primarily on wheat, grain sorghum, and soybean, but research is also conducted on alternative crops such as corn and sunflower. Investigations include variety and hybrid performance tests, chemical weed control, reduced tillage/notillage systems, crop rotations, cover crops, fertilizer use, planting practices, and disease and insect resistance and control. The Harvey County Experiment Field consists of two tracts. The headquarters tract (North Unit), 75 acres immediately west of Hesston on Hickory Street, is all Ladysmith silty clay loam with 0-1% slope. The South Unit, 4 mi south and 2 mi west of Hesston, is composed of 142 acres of Ladysmith, Smolan, Detroit, and Irwin silty clay loams as well as Geary and Smolan silt loams. All have a 0-3% slope. Soils on the two tracts are representative of much of Harvey, Marion, McPherson, Dickinson, and Rice counties as well as adjacent areas. These are deep, moderately well to well-drained, upland soils with high fertility and good water-holding capacity. Water runoff is slow to moderate. Permeability of the Ladysmith, Smolan, Detroit, and Irwin series is slow to very slow, whereas permeability of the Geary series is moderate. 2006-2007 Weather Information Dry conditions in September and early October allowed ample time for wheat planting preparations and choice of planting date. Modest rains returned after planting, providing adequate moisture for prompt and complete emergence and early growth. However, November had no meaningful HC-1 rainfall, and conditions remained dry until mid-December, when two excellent rains and several smaller showers led to an aboveaverage month for precipitation. Average temperatures were several degrees cooler than normal in October, slightly above normal in November, and about 5.5°F above normal in December. Except in February, winter precipitation was above normal. The coldest period of the winter occurred between mid-January and mid-February, when single-digit temperatures were recorded on 10 days. Mean temperatures were somewhat below normal in January and February but well above normal in March. Wheat survival was normal. Rainfall was about an inch below normal in April but close to double the normal in May. June rainfall was below average but impeded wheat harvest somewhat. Mean temperatures were much cooler than normal in April, near normal in May, and somewhat cooler than usual in June. The major event of the wheat growing season occurred on April 7 and 8; during the early morning hours, temperatures dipped below 25°F for a combined total of 14 hours. Wheat was just past the jointing stage, and main stems were seriously injured by the cold temperatures. Fungal diseases played a significant role in yield reduction of freeze-injured wheat with tillers that matured later than usual. Leaf rust became the dominant disease by mid-May, and leaves began turning yellow at that point. Mild conditions in March facilitated early corn planting and seedling development. However, the severe freeze in early April decimated emerged corn. Subsequent opportunities for timely corn planting were extremely limited because of prolonged wet weather. Soybean and grain sorghum plantings also were delayed somewhat. The last spring freeze occurred 4 days earlier than normal on April 15. In July, average temperatures were 2.5°F below normal. Warmer conditions prevailed in August and September with mean temperatures 2.8 and 1.4°F above normal. The hottest temperatures of the summer occurred from August 7 to 15; during this time, 5 days had temperatures at or above 100°F. Although August had 1.13 in. less rainfall than normal, the summer was favorable for all row crops, with better-than-average conditions overall. September also was drier than usual, with only a light rain interfering with corn harvest. October had near-normal total precipitation, but most of it occurred in the first half of the month and ahead of most grain sorghum and soybean harvesting. Late-planted corn suffered severe lodging in some areas as a result of southwestern corn borer activity. Soybean and grain sorghum generally had no insect or disease problems of significance. Sunflower suffered serious damage from head-clipper weevil and lesser injury from stem weevil. The first killing frost of the fall occurred 8 days later than normal on October 23. The frost-free season spanned 191 days, 12 days longer than normal. Late arrival of freezing temperatures in the fall benefited late-planted row crops, most of which matured before the advent of cold temperatures. A field experiment consisting of 11 no-till crop rotations was initiated in 2001 in central Kansas on Ladysmith silty clay loam. Cropping systems involving winter wheat (W), corn (C), grain sorghum (GS), doublecrop grain sorghum ([GS]), soybean (SB), double-crop soybean ([SB]), and sunflower (SF) are as follows: W-C-SB, W-[SB]-C-SB, W-SB-C, W-GS-SB, W-[SB]-GS-SB, W-[GS]-GS-SB, W-GS-SF, W-[SB]-GS-SF, W-[GS]-GS-SF, GS-C-SB, and GS-GS-GS. Data collection to determine cropping system effects began in 2004. In 2007, wheat suffered severe freeze damage in early April. Highest wheat yields occurred in rotations in which wheat followed sunflower and averaged 30.3 bu/a. Wheat following corn and soybean produced 7.4 and 3.2 bu/a less, respectively, than wheat after sunflower, but from 20042007, wheat performed best after soybean with a top yield of 58.2 bu/a, producing 7.1 and 11.8 bu/a less following corn and sunflower, respectively. Inclusion of [GS] or [SB] in the rotation had no apparent effect on wheat. Corn averaged 78.4 bu/a without a significant crop rotation effect. Grain sorghum production was greatest in rotations in which grain sorghum followed soybean or wheat, averaging 95.9 and 103.5 bu/a, respectively. Grain sorghum yields were lowest following [GS] or full-season grain sorghum, averaging 77.1 to 77.9 bu/a. Intermediate grain sorghum yields of 90.7 bu/a occurred following [SB]. Double-crop grain sorghum produced 46.9 to 57.2 bu/a without significant rotation effect. Soybean produced the best average yield of 34.7 bu/a in all rotations involving corn and wheat or in the rotation with grain sorghum and wheat without double crops. Soybean yields were 5.3 bu/a less in rotations with grain sorghum and wheat that included [GS] or [SB] and in the GS-C-SB rotation. Doublecrop soybean yields ranged from 11.5 to 16.1 bu/a and tended to be slightly higher in HC-3 W-[SB]-GS-SF than in the other rotations. Sunflower yielded 798 lb/a with no rotation effect. Introduction The number of acres devoted to no-till crop production in the United States has risen steadily in recent years, most notably since 2002. According to the Conservation Technology Information Center, no-till was used on 62.4 million acres, nearly 23% of the cropland in 2004. At that time, Kansas ranked seventh in the nation with 4.2 million acres of no-till annual crops, representing 21.2% of planted acres. Anecdotal information suggests that no-till annual crop acreages have continued to increase. Soil and water conservation issues; cost of labor, fuel, and fertilizers; changes in government farm programs; development of glyphosatetolerant crops; and lower glyphosate herbicide cost all contribute to no-till adoption by growers. Crop rotation reduces pest control costs, enhances yields, and contributes significantly to successful no-till crop production. Selecting appropriate crop rotations provides adequate diversity of crop types to facilitate realization of these benefits and sufficient water-use intensity to take full advantage of available moisture. In central and south central Kansas, longterm, no-till research on multiple crop rotations is needed to determine profitability and reliability of these systems. This experiment includes 10 three-year rotations. Nine of these involve wheat, corn or grain sorghum, and soybean or sunflower. One rotation consists entirely of row crops. Continuous grain sorghum serves as a monoculture check treatment. Double-crop soybean and [GS] after wheat are used as intensifying components in five of the rotations. One complete cycle of these rotations was completed in 2003. Official data collection began in 2004. The experiment site was located on a Ladysmith silty clay loam where no-till soybean had been grown in 2000. Lime was applied according to soil test recommendations and incorporated by light tillage in late fall of that year. Detailed soil sampling was done in early April 2001, just before establishment of the cropping systems. Average soil test values at that time included pH 6.2, organic matter 2.7%, available phosphorus (P) 46 lb/a, and exchangeable potassium 586 lb/a. Eleven crop rotations were selected to reflect adaptation across the region. These involved winter wheat (W), corn (C), grain sorghum (GS), double-crop grain sorghum ([GS]), soybean (SB), double-crop soybean ([SB]), and sunflower (SF) as follows: W-C-SB, W-[SB]-C-SB, W-SB-C, W-GS-SB, W-[SB]-GS-SB, W-[GS]-GS-SB, W-GS-SF, W-[SB]-GS-SF, W-[GS]-GS-SF, GS-C-SB, and GS-GS-GS. The experiment uses a randomized complete block design with four replications of 31 annual treatments representing each crop in each rotation. Plots to be planted to wheat following corn were sprayed with Roundup Original Max in mid-September 2006 to control lateemerged weeds. Overley wheat was planted into corn, soybean, and sunflower stubble on October 14 in 7.5-in. rows at 90 lb/a with a John Deere 1590 no-till drill with single-disk openers. Wheat was fertilized with 120 lb/a N and 32 lb/a P2O5 as preplant broadcast ammonium nitrate and as in-furrow diammonium phosphate at planting. No herbicides were used on wheat in any of the cropping systems. Wheat was harvested on July 9, 2007. Wheat plots to be planted to corn were sprayed with Roundup Original Max in early July and late September 2006. These and soybean plots to be planted to corn in 2007 were sprayed with Roundup plus 2,4-DLVE in late November. A few days before planting, corn plots were sprayed with Roundup Original Max + Dual II Magnum + very low rates of Clarity and 2,4-DLVE. Subsequently, weeds were controlled with a single postemergence application of Roundup Original Max. A White no-till planter with double-disk openers on 30-in. centers was HC-4 used to plant Pioneer 35P80 RR with Poncho insecticide at approximately 19,000 seeds/a on May 21, 2007. All corn was fertilized with 30 lb/a N and 30 lb/a P2O5, banded 2 in. from the row at planting. Corn after wheat, [SB], and grain sorghum received an additional 95 lb/a N, and corn after soybean received 65 lb/a N as 28-0-0 injected in a band 10 in. on either side of each row on June 9. Corn was harvested on September 21, 2007. Wheat plots to be planted to grain sorghum were treated the same as corn during the preceding summer through the time that corn was planted. Because of later planting, grain sorghum plots required an additional Roundup application in June. AAtrex 4L was applied soon after grain sorghum planting to complete residual weed control. Sorghum Partners KS 585 with Concep III safener and Cruiser insecticide was planted at approximately 30,000 seeds/a in 30-in. rows with 30 lb/a N and 30 lb/a P2O5 banded 2 in. from the row on June 20. Sorghum after wheat, grain sorghum, [GS], and [SB] received an additional 60 lb/a of N, and grain sorghum after soybean received 30 lb/a of N as 28-0-0 injected in a band 10 in. on either side of each row in mid-July. Sorghum was harvested on October 31, 2007. Double-crop grain sorghum plots received an application of Roundup Weather Max just before planting. Pioneer 87G57 with Concep III safener and Cruiser insecticide was planted on July 11 with the same procedures used for full-season grain sorghum. An additional 30 lb/a N were injected on August 15. Postemergence application of AAtex 4L + COC was made with drop nozzles on August 14. Double-crop grain sorghum was harvested on October 31, 2007. Wheat and row crop plots to be planted to soybean received the same herbicide applications as corn. Asgrow AG3802 RR soybean was planted at 115,000 seeds/a in 30in. rows on June 5. During the season, a single application of Roundup Original Max was made on July 9. Soybean was harvested on October 1, 2007. Double-crop soybean had a preplant application of Roundup Weather Max. Asgrow A3802 RR soybean was planted as a double crop at 115,000 seeds/a in 30-in. rows on July 11. One additional Roundup application was required in late August. Double-crop soybean was harvested on October 26, 2007. All sunflower plots were sprayed with Roundup Original Max + Dual II Magnum + very low rates of Clarity and 2,4-DLVE on May 19. A follow-up application of Roundup was made a month later, just ahead of sunflower planting. Triumph s672 sunflower was planted on June 20 at 28,000 seeds/a with 30-30-0 fertilizer banded 2 in. from the row. A 0.33x rate of Dual II Magnum also was applied to strengthen preemergence weed control. An additional 40 lb/a N were sidedress dribble applied on August 18. Sunflower was harvested on October 27, 2007. Results Wheat Wheat stand establishment was excellent in all crop rotations. Early spring prospects were those of a bumper crop. However, hard freezing temperatures on April 7 and 8 nearly resulted in total destruction of wheat in this experiment. Heading occurred in mid-May, and following the freeze, there were no significant differences in wheat maturity among the rotations (Table 2). Similarly, there were no significant differences in plant heights. Plant N concentration tended to be inversely related to grain yield but was not consistent. Wheat after corn averaged 1.94% N, 0.37% and 0.33% N more than after sunflower and soybean, respectively. Unlike the long-term yield trend, highest wheat yields occurred in rotations in which wheat followed sunflower and averaged 30.3 bu/a, likely because wheat was in a less advanced stage when the freeze occurred, resulting in less freeze injury. Double cropping with soybean or grain sorghum in selected rotations did not influence wheat yield. The lowest wheat yield (22.9 bu/a) occurred where wheat followed corn, possibly because of increased incidence of Fusarium head blight (Table 2). When averaged over all rotations for the last 4 years, wheat following soybean had the highest yield, 58.2 bu/a, which was 7.1 and 11.8 bu/a more than wheat after corn and sunflower, respectively. Grain test weights averaged 49.1 lb/bu in wheat after sunflower and soybean and 46.5 lb/bu in wheat after corn. Grain protein levels followed the trends noted for plant N concentration with averages ranging HC-5 from 11.9% to 12.8% among rotations in which wheat followed soybean or corn. Grain protein in wheat after sunflower was significantly lower (11.4%). In general, antecedent crop effects were much more significant than overall rotation effects in determining wheat performance. Corn Corn emerged about 9 days after planting. Final corn populations averaged 18,260 plants/a (Table 3) and were not significantly affected by crop rotation. Corn reached the half-silking stage 60 to 61 days after planting, tending to be slightly later following wheat in rotation but without statistical significance. Leaf N averaged 2.39% with no significant rotation effect. Lodging was greater than usual as a result of southwestern corn borer activity and ranged from 14% to 20% without a consistent relationship to crop rotation. Corn yields averaged 78.4 bu/a without rotation effect. Test weight was highest in corn after grain sorghum (57.2 lb/bu) and lowest in corn after wheat with an average of 55.1 lb/bu. Number of ears/plant averaged 1.03 without a significant effect by crop rotation. Grain sorghum Grain sorghum planting was delayed by wet weather. Emergence occurred rapidly at 5 days after planting. Final populations ranged from 23,300 to 26,900 plants/a. Lowest fullseason grain sorghum plant counts occurred in GS-GS-GS and W-[GS]-GS-SB, whereas populations differed little across remaining rotations. On average, full-season grain sorghum reached half-bloom stage at 57 days after planting. In W-[GS]-GS-SB, W-[GS]GS-SF, and GS-GS-GS, half-bloom occurred 2 to 4 days later than the average in other crop rotations. Leaf N levels ranged from 3.12% to 3.69% among rotations, with the highest mean values in grain sorghum after wheat and soybean and lowest mean values in grain sorghum following full-season grain sorghum or [GS]. Grain sorghum production was greatest in rotations in which grain sorghum followed soybean or wheat and ranged from 95.9 to 103.5 bu/a. Grain sorghum yields were lowest in rotations following grain sorghum or [GS], averaging 77.1 to 77.9 bu/a, and intermediate following [SB]. Grain test weight averaged 60.6 lb/bu with minor differences among rotations. Number of heads/plant ranged from 1.31 to 1.93. Lowest head counts tended to occur in rotations in which grain sorghum followed grain sorghum or [GS], and highest head counts occurred in W-GS-SF. Wheat following sunflower in 2006 produced about half the yield of wheat in other rotations. Consequently, grain sorghum following wheat in the sunflower rotation likely benefited from a more favorable soil moisture reserve. Lodging was insignificant. Double-crop grain sorghum production averaged 52.1 bu/a, about 58% of the fullseason crop. Rotation effect on [GS] yield was not significant. Stands averaged 28,100 plants/a without treatment effect. Other variables measured in [GS] tended to be unaffected by crop rotation. Soybean Soybean emerged less than a week after planting. Stands were excellent among all rotations (Table 4). Full-season soybean developed plant heights that averaged 31 in., generally reached maturity at 111 days after planting, and produced a respectable mean yield of 32.4 bu/a across all rotations. However, soybean produced the best average yield of 34.7 bu/a in rotations involving corn and wheat or in the rotation with grain sorghum and wheat without double crops. Soybean yields were 5.3 bu/a less in rotations with grain sorghum and wheat that included [GS] or [SB] and in the GS-C-SB rotation. There was no lodging. Double-crop soybean stands also were excellent. Plant heights averaged 18 in. with no rotation effect. Double-crop soybean reached maturity without treatment effect at 101 days after planting. No lodging occurred. Yields of [SB] ranged from 11.5 to 16.1 bu/a and tended to be slightly higher in W-[SB]-GS-SF than in other rotations. Sunflower Sunflower emerged 5 days after planting. Populations averaged 25,200 plants/a. Triumph s672 NuSun short-stature sunflower reached half-bloom stage at 56 days and had an average height of 38 in. Sunflower was severely affected by head-clipper weevils. As a result, yields averaged only 798 lb/a. Lodging averaged 10%. None of these variables were affected by crop rotation. Yield2 Preceding crop main effect means: Sorghum Wheat 103.5 102.9 60.8 25.3 56 1.80 2 3.68 [Soybean] 90.7 95.6 60.7 25.2 56 1.67 3 3.44 Soybean 95.9 100.4 60.9 26.9 55 1.49 1 3.52 [Sorghum] 77.9 88.6 60.1 24.9 59 1.39 0 3.29 Sorghum 77.1 90.9 60.4 23.3 59 1.34 1 3.16 LSD 0.055 12.1 0.5 2.0 1.9 0.22 NS 0.28 LSD 0.105 10.0 0.4 1.7 1.6 0.18 NS 0.23 1 C = corn, GS = grain sorghum, SB = soybean, SF = sunflower, W = wheat, and [ ] = double crop. 2 Means of four replications adjusted to 15.5% moisture (corn) or 12.5% moisture (grain sorghum). 3 Maturity expressed as follows: corn B days from planting to 50% silking, and grain sorghum - number of days from planting to half-bloom. 4 N level of the ear leaf plus one in corn and of the flag leaf in sorghum. 5 Estimate based on the average number of crop sequences involving the same preceding crop to full-season grain sorghum = 1.6. Sunflower W-GS-SF 801 1686 25.1 37 56 W-[SB]-GS-SF 866 1555 26.1 38 56 W-[GS]-GS-SF 728 1554 24.4 38 57 LSD 0.05 NS NS NS NS LSD 0.10 NS NS NS NS 1 C = corn, GS = grain sorghum, SB = soybean, SF = sunflower, W = wheat, and [ ] = double crop. 2 Means of four replications adjusted to 13% moisture (soybean) or 10% moisture (sunflower in lb/a). 3 Stand expressed as a percentage for soybean and as plant population in thousands per acre for sunflower. 4 Sunflower maturity expressed as number of days from planting to half-bloom. 5 Estimate based on the average number of crop sequences involving the same preceding crop to full-season soybean = 2.3. 100 100 100 100 100 100 100 94 100 100 NS NS EFFECTS OF LATE-MATURING SOYBEAN AND SUNN HEMP SUMMER COVER CROPS AND NITROGEN RATE IN A NO-TILL WHEAT-GRAIN SORGHUM ROTATION Wheat and grain sorghum were grown in three no-till crop rotations, two of which included either a late-maturing Roundup Ready soybean or a sunn hemp cover crop established following wheat harvest. Nitrogen (N) fertilizer was applied to both grain crops at rates of 0, 30, 60, and 90 lb/a. Experiments were conducted on adjacent sites where different phases of the same rotations were established. On the first site, late-maturing soybean and sunn hemp were grown in the third cycle of the rotations in 2006. These crops produced 1.37 and 2.08 ton/a of above-ground dry matter with 68 and 113 lb/a of potentially available N, respectively. Both legumes tended to increase grain sorghum leaf N concentration and grain yield but more so at low N rates and more consistently in the case of sunn hemp. At 90 lb/a N, sorghum leaf N levels were similar in all rotations. Grain sorghum yield tended to be higher at most N rates following soybean than in the rotation without a cover crop, but differences often were not significant. Conversely, sorghum yields following sunn hemp were consistently highest at each N rate with a top yield of 112.8 bu/a at 90 lb/a N. However, at this N rate, sorghum yields did not differ significantly between the rotation with sunn hemp vs. no cover crop. On the second site, wheat followed grain sorghum after these cover crops had been grown for the first time in the rotations in 2005. In that season, soybean and sunn hemp produced an average of 2.42 and 4.14 ton/a with corresponding N yields of 103 and138 lb/a, respectively. Wheat suffered severe freeze damage in early April 2007, resulting in yields of only 19 to 22 bu/a in the best treatments. Grain test weights as well as yields were low and not meaningfully affected by residue from cover crops. Wheat plant N HC-10 was relatively high at zero N fertilizer in all rotations because of low dry matter production but tended to be highest at 90 lb/a N in rotations with cover crops. N content and grain yield were greatest at 90 lb/a N, but yield increase with the last increment of fertilizer was small. Introduction Research at the Kansas State University Harvey County Experiment Field over an 8year period explored the use of hairy vetch as a winter cover crop following wheat in a winter wheat-sorghum rotation. Results of long-term experiments showed that between September and May, hairy vetch can produce a large amount of dry matter with an N content of approximately 100 lb/a. However, using hairy vetch as a cover crop also has significant disadvantages including cost and availability of seed, interference with control of volunteer wheat and winter annual weeds, and the possibility of hairy vetch becoming a weed in wheat after sorghum. New interest in cover crops has been generated by research in other areas showing the positive effect these crops can have on overall productivity of no-till systems. In the current experiment, late-maturing soybean and sunn hemp, a tropical legume, were evaluated as summer cover crops for their effect on no-till sorghum grown in the spring after wheat harvest as well as on double-crop, no-till wheat after grain sorghum. In 4 site-years during the period 2002 through 2006, soybean and sunn hemp produced average N yields of 102 and124 lb/a, respectively. Averaged over N rates, soybean and sunn hemp resulted in 4-year average grain sorghum yield increases of 7.3 and 13.5 bu/a, respectively. Residual effects of soybean and sunn hemp on wheat after sorghum averaged over N rates were minor, with 3-year yields averaging 1.6 and 1.7 bu/a, respectively, more than wheat in the rotation without cover crops. Procedures Experiments were established on adjacent Geary silt loam sites that had been used for hairy vetch cover crop research in a wheatsorghum rotation from 1995 to 2001. In accordance with the previous experimental design, soybean and sunn hemp were assigned to plots where vetch had been grown, and remaining plots retained the no cover crop treatment. The existing factorial arrangement of N rates on each cropping system also was retained. In 2007, grain sorghum was grown on Site 1 in the third cycle of the rotations. Wheat was produced on Site 2 at the end of the first cycle of the rotations. Grain Sorghum Cover crop planting in the preceding summer was delayed by late seed arrival. Weeds in wheat stubble were controlled with glyphosate application in early July and follow up treatment 1 day before planting. Asgrow AG7601 Roundup Ready soybean and sunn hemp seed were treated with respective rhizobium inoculants and no-till planted in 7.5-in. rows with a JD 1590 drill on August 8, 2006, at 60 lb/a and 10 lb/a, respectively. Both crops emerged approximately 1 week later. Sunn hemp began flowering in early to mid-October. At that time, soybean had little pod development. Cover crops were terminated on October 13 by rolling with a crop roller. Plots were subsequently sprayed with glyphosate to control crop or weed escapes. The first killing frost of the fall occurred 5 days later. Forage yield of each cover crop was determined by harvesting a 3.28 ft2 area in each plot just before termination. Samples were subsequently analyzed for N content. Weeds were controlled during the fallow period after cover crops with glyphosate, 2,4DLVE and Clarity. Pioneer 85G01 grain sorghum treated with Concep III safener and Cruiser insecticide was planted in 30-in. rows at approximately 42,000 seeds/a on June 6, 2007. Atrazine and Dual II Magnum were applied preemergence for residual weed control before and/or shortly after sorghum planting. All plots received 37 lb/a P2O5 HC-11 banded as 0-46-0 at planting. Nitrogen fertilizer treatments were applied as 28-0-0 injected 10 in. from the row on June 11. Grain sorghum was combine harvested on October 3, 2007. Wheat Grain sorghum on Site 2 was combine harvested on November 9, 2006. N rates were immediately reapplied as broadcast 34-0-0. Variety Jagger winter wheat was no-till planted in 7.5-in. rows with a JD1590 drill the same day at 90 lb/a with 32 lb/a P2O5 fertilizer banded as 0-46-0 in the furrow. Wheat was harvested on July 9, 2007. Results Grain Sorghum During the 5 days preceding cover crop planting in 2006, rainfall totaled 1.02 in. The next rains occurred 2 and 6 days after planting; a total of 1.52 in. was received. Stand establishment of both soybean and sunn hemp was good. Although August rainfall was well above normal, September and October were much drier than usual. Late-maturing soybean reached an average height of 19 in., showed limited pod development, and produced 1.37 ton/a of above-ground dry matter with an N content of 2.50% or 68 lb/a (Table 5). Sunn hemp averaged 53 in. in height and produced 2.08 ton/a with 2.70% N or 113 lb/a of N. Soybean and sunn hemp suppressed volunteer wheat to some extent but failed to give the desired level of late summer control. Volunteer wheat control was similar for both crops, averaging 67%. The 2007 grain sorghum crop emerged 5 days after planting; final stands averaged 38,700 plants/a. The season brought some drought stress, but only 5 days had temperatures at or above 100°F. Summer was generally favorable for sorghum, with better-than-average conditions overall. Both cover crop and N rate effects on grain sorghum were significant. Soybean and sunn hemp significantly increased sorghum nutrient concentration by 0.17% and 0.27% N, respectively, at the zero N rate. Where sorghum followed soybean and N fertilizer was applied, leaf N levels were comparable to those of sorghum in rotation without a cover crop. However, in rotations with sunn hemp vs. no cover crop, sorghum leaf N was significantly greater at 30 and 60 lb/a N but not at 90 lb/a N. The main effect of soybean and sunn hemp, averaged across N fertilizer rates, significantly increased sorghum leaf nutrient levels by 0.07% N and 0.17% N, respectively. Leaf N averaged over cropping systems increased significantly with each increment of N fertilizer. Soybean cover crop tended to increase sorghum yields at all but the highest N rate, but the increase was significant only at the 60 lb/a N rate. Conversely, with sunn hemp in the rotation, sorghum yields increased across all N rates. However, the sunn hemp benefit was not significant at the 90 lb/a N rate. The positive effect of soybean and sunn hemp cover crops was seen in sorghum yield improvements of 4.0 and 12.2 bu/a, respectively, averaged over N rate. Yields averaged over cropping systems increased significantly at all but the 90 lb/a rate of N fertilizer. Cover crops did not affect grain sorghum plant population or grain test weight and had no meaningful effect on half-bloom date. The number of heads/plant tended to increase slightly with N rate in sorghum rotations with soybean or no cover crop. In sorghum after sunn hemp, the number of heads/plant increased only at the highest N rate. Wheat The first cycle of the crop rotations on Site 2 began in 2005, when soybean and sunn hemp produced an average of 2.42 and 4.14 ton/a with corresponding N yields of 103 and138 lb/a, respectively (Table 6). In 2006, averaged across N rate, grain sorghum yielded 96.1 bu/a after soybean and 101.4 bu/a following sunn hemp. The 2007 wheat growing season was overshadowed by severe cold temperatures in early April that resulted in serious damage to the crop. Grain test weights as well as yields were low and not meaningfully affected by residue from cover crops. Similarly, plant heights were not affected by cropping history. Wheat plant N was relatively high at the zero N fertilizer rate in all rotations because of low dry matter production but tended to be highest at 90 lb/a N in rotations with cover crops. Effect of N rate on most wheat variables was significant. Plant height, N content, and grain yield were greatest at 90 lb/a N, but yield increase with the last increment of fertilizer was small. Yields of 19 to 22 bu/a at top N rates were respectable under existing conditions. Grain Sorghum Half4 Stand Bloom 1000s/a days EFFECTS OF PLANTING DATE, HYBRID MATURITY, AND PLANT POPULATION IN NO-TILL CORN M.M. Claassen Summary Three Pioneer corn hybrids (38H66, 35P80, and 33B49) representing 98-day, 106day, and 112-day maturities were planted in a soybean rotation under no-till conditions on April 23, May 21, and June 5 and had final populations of 14,000, 18,000, and 22,000 plants/a. A March 13 planting was destroyed by unseasonable cold in early April. Subsequent wet weather resulted in deviation from the remaining targeted early- and midApril planting dates. Despite planting postponement, relatively low moisture stress during the remainder of the season resulted in reasonably good dryland corn yields for this area. Later plantings were seriously affected by lodging resulting from southwestern corn borer activity. All treatment factors significantly affected corn. Planting date had the largest effect on length of time to reach half-silk stage. Corn planted on May 21 and June 5 reached silking 6 and 14 days faster, respectively, than corn planted on April 23. Corn yields averaged 114 bu/a when planted on April 23 but declined by 23% and 21% with successive plantings in May and early June. Corn hybrid 33B49 produced an average of 102 bu/a, whereas the earlier-maturing 38H66 and 35P80 had 9% and 6%, respectively, lower yields. Maximum yields occurred with the highest plant population (22,000 plants/a). At 18,000 and 14,000 plants/a, yields declined by 3% and 14%, respectively. In 2004, yields were largest with the latest planting date (mid-April), but in 2005 and 2006, highest yields occurred with the earliest planting (mid-March). In 2006, yields were low and not affected by plant population. In 2004 and 2005, maximum yields occurred with latest maturing hybrid and highest plant population. Grain test weight was good in 2007, tended to be best with the April and May plantings, and was not appreciably affected by hybrid or plant population. Number of ears/plant was not greatly influenced by treatment factors but HC-15 was slightly greater than one ear/plant with the earliest planting, earliest maturing hybrid, and lowest plant population. In central and south central Kansas, dryland corn often does not perform as well as grain sorghum under existing seasonal weather conditions, which usually involve some degree of drought. Nevertheless, corn is preferred as a rotational crop by some producers because earlier growth termination and harvest facilitate planting of double-crop, no-till wheat in rotations. Genetic gains in corn drought tolerance as well as no-till planting practices that conserve soil moisture have encouraged producer interest in growing corn despite increased risk of crop failure. Planting date, hybrid maturity, and plant population all have a major effect on dryland corn production. Previous research at this location indicated that highest dryland yields occurred at plant populations of 14,000 or 18,000 plants/a. This experiment was initiated in 2004 to determine if drought effects on notill corn can be minimized by early planting dates, use of hybrids ranging in maturity from 97 to 112 days, and populations of 14,000 to 22,000 plants/a. Actual planting dates were March 18, April 2, and April 15 in 2004; March 14, April 4, and April 16 in 2005; and March 16, March 31, and April, 14 in 2006. Hybrids planted in 2004 and 2005 were Pioneer 38H67, 35P12, and 33B51, which have maturities of 97, 105, and 111 days, respectively. Hybrids planted in 2006 and 2007 were Pioneer 38H66, 35P80, and 33B49, which have maturities of 98, 106, and 112 days, respectively. The experiment was conducted on a Ladysmith silty clay loam site that had been cropped to no-till soybean in 2006. Corn was fertilized with 95 lb/a N and 37 lb/a P2O5 as CHLORIDE FERTILIZATION FOR WHEAT AND GRAIN SORGHUM W.B. Gordon Summary Research on chloride (Cl) application on wheat has shown significant yield response in Kansas. Chloride affects progression of some diseases by suppressing or slowing infection; however it does not completely eliminate diseases. Chloride responses have been noted even in absence of disease, suggesting that some soils in Kansas may not be able to supply needed amounts of Cl. Soil test calibration experiments have shown that when soil chloride levels (0-24 in.) are below 20 to 30 lb/a, responses to applied chloride are likely. In these experiments with wheat and grain sorghum, Cl consistently increased grain yield. Chloride has been reported to affect plant diseases in wheat and other grains by either suppressing the disease organism or improving overall plant health, allowing the plant to withstand infection. Researchers from across the Great Plains have shown yield increases from Cl application. The objective of these experiments was to evaluate Cl fertilization on wheat and grain sorghum in north central Kansas. In 2004-2007, Cl rates of 10, 20, and 30 lb/a were applied to wheat variety 2145 at the North Central Kansas Experiment Field on a Crete silt loam soil. An unfertilized check plot also was included. The Cl source used was ammonium chloride (6% nitrogen (N) and 16.5% Cl). Nitrogen was balanced on all plots; each plot received 90 lb/a N. Soil test Cl level at the test site was 15 lb/a in the top 24 in. of soil. Chloride was applied broadcast in the spring before jointing stage. In 2007, the same Cl rates were applied to wheat variety Overley. Chloride was applied with or without the fungicide Quilt at 14 oz/a. Fungicide was applied at flag leaf emergence. During 2004NC-18 2007, chloride rates (0, 20, and 40 lb/a Cl) and method of application were evaluated on grain sorghum. Application methods included broadcast on the soil surface immediately after planting and as a starter placed 2 in. to the side and 2 in. below the seed at planting. Chloride source was liquid ammonium chloride. Ammonium chloride (NH4Cl) was added to a starter fertilizer containing 30 lb/a N and 30 lb/a P2O5. Plots receiving broadcast NH4Cl also received the same amount of starter fertilizer but without the NH4Cl. Nitrogen was balanced; all plots received 150 lb/a N regardless of NH4Cl treatment. The experiment was conducted in areas where soil test Cl was 14-18 lb/a. Results Averaged over the 3-year period, adding 10 lb/a Cl increased grain yield of 2145 wheat 5 bu/a over the unfertilized check (Table 13). Adding higher rates of Cl did not result in any increases in yield. In 2007, adding Cl to Overley wheat increased grain yield 8 bu/a over the unfertilized check (Table 14). When no Cl was applied, fungicide application improved grain yield 5 bu/a more than the no-fungicide check. When 10 lb/a Cl was applied with fungicide, yields were 4 bu greater than with Cl alone. At the two higher Cl rates, fungicide application did not result in a statistically significant yield increase. Applying Cl increased grain sorghum yield in all 3 years of the experiment (Table 15). Averaged over years and methods of application, adding 20 lb/a Cl increased yield 11 bu/a over the untreated check. Applying Cl at a rate higher than 20 lb/a Cl did not significantly increase grain yield. Applying Cl as a 2x2 starter significantly increased grain yield in only 1 year of the 3year study. Averaged over years, there was no difference in application method. Results suggest that when soil test Cl levels are below the 20 lb/a level, consistent yield increases can be obtained with application of Cl-containing fertilizer. 10 20 30 KANSAS RIVER VALLEY Introduction, Soil Description, Weather Information............................................................KRV-1 Corn Herbicide Performance Test .........................................................................................KRV-2 Fungicides on Corn ................................................................................................................KRV-6 Macronutrient Fertility on Irrigated Corn in a Corn/Soybean Rotation ................................KRV-7 Experiment Field Personnel Larry D. Maddux, Ph.D., Agronomist-in-Charge Charles Clark, Plant Science Technician II William Riley, Plant Science Technician I David Schooler, Assistant Scientist EAST CENTRAL Introduction, Soil Description, Weather Information............................................................... EC-1 Evaluation of Nitrogen Rates and Starter Fertilizer for Strip-Till Corn in Eastern Kansas................................................................................................................ EC-2 Evaluation of Strip-Till and No-Till Tillage Fertilization Systems for Growing Grain Sorghum Planted Early and at the Traditional Planting Time in Eastern Kansas................................................................................................................ EC-5 Planting Date, Hybrid Maturity, and Plant Population Effects on Corn................................... EC-9 Experiment Field Personnel Larry D. Maddux, Ph.D., Agronomist-in-Charge Keith A. Janssen, Ph.D., Soil Management and Conservation Specialist James M. Kimball, Plant Science Technician II Mark Horstick, Student Ryan Schaub, Student KANSAS RIVER VALLEY EXPERIMENT FIELD Introduction The Kansas River Valley Experiment Field was established to study management and effective use of irrigation resources for crop production in the Kansas River Valley. The Paramore Unit consists of 80 acres located 3.5 mi east of Silver Lake on U.S. Highway 24, then 1 mi south of Kiro, and 1.5 mi east on 17th street. The Rossville Unit consists of 80 acres located 1 mi east of Rossville or 4 mi west of Silver Lake on U.S. Highway 24. Soil Description Soils on the two fields are predominately in the Eudora series. Small areas of soils in the Sarpy, Kimo, and Wabash series also occur. Except for small areas of Kimo and Wabash soils in low areas, the soils are well drained. Soil texture varies from silt loam to sandy loam, and the soils are subject to wind erosion. Most soils are deep, but texture and surface drainage vary widely. The frost-free season was 197 and 203 days at the Paramore and Rossville Units, respectively (173 days average). The last spring freeze was on April 9 at both fields (average April 21), and the first fall freeze was October 25 and October 31 for the Paramore and Rossville Units, respectively (average October 11). There were 44 and 38 days above 90°F at the Paramore and Rossville Units. Precipitation was 4 to 10 in. below normal for the growing season (Table 1). Precipitation was below average from November through April. At the Rossville Unit, precipitation was above normal in May and slightly above normal in June. Precipitation in July and August was slightly below normal. Some sudden death syndrome was observed in soybeans, but the disease was not as bad as in previous years. Corn and soybean yields were good at both fields. 2006-2007 2006-2007 Month October November December January February March April May June July August September Total CORN HERBICIDE PERFORMANCE TEST Larry Maddux Summary This study was conducted at the Rossville Unit. Herbicide applications consisting of five preemergence (PRE), nine two-pass (PRE plus early or mid-postemergence (EP or MP), and one EP were compared. Ratings made on June 25 indicated excellent control of Palmer amaranth (PA) and common sunflower (CS) (greater than 90% control with all treatments). Control of large crabgrass (LC) ranged from 80% to 100%. Ivyleaf morningglory (IM) control ranged from 23% to 88% with eight treatments resulting in greater than 80% control. All treatments resulted in much greater yield than the untreated check; only two treatments yielded lower than the others. Controlling weeds in row crops with chemical weed control and cultivation can reduce weed competition and, in turn, weed yields. Timeliness of application is a major factor in effective weed control. This study compared the effectiveness of 15 herbicide treatments including PRE, EP, and PRE plus EP or PRE plus MP for controlling LC, PA, CS, and IM. The test was conducted on a Eudora silt loam soil previously cropped to soybean at the Rossville Unit. It included five PRE treatments, one EP treatment, nine PRE plus EP or MP, and one untreated check. The test site had a pH of 6.9 and an organic matter content of 1.1%. Hoegemeyer 8778, Herculex, LL RR2 hybrid corn was planted April 30 at 29,600 seeds/a in 30-in. rows. Anhydrous ammonia at 150 lb/a nitrogen (N) was applied preplant, and 120 lb/a of 10-34-0 fertilizer KRV-2 was banded at planting. Herbicides were broadcast in 15 gal/a with 8003XR flat fan nozzles at 17 psi. The experimental design was a randomized complete block with three replications. PRE applications were made April 30. EP treatments were applied May 29 to 4-leaf corn, 1- to 2-in. LC, 2- to 3-in. PA, 1- to 6-in. CS and 1- to 3-in. IM. MP treatments were applied June 4 to 5-leaf corn, 1- to 2-in. LC, 2- to 3-in. PA, 1- to 6-in. CS and 1- to 2-in. IM. Populations of all four weed species were moderate to heavy. However, weed populations were generally fairly light at postemergence time in plots receiving a preemergence treatment. Plots were not cultivated. The reported weed control ratings were made June 25. A total of 0.76 in. of rain was received from May 1 to 3. On May 6, 5.07 in. of rain was received. Plots were irrigated as needed. The test was harvested September 25 using a modified John Deere 3300 plot combine. Results Rainfall of 0.76 in. occurred over the 3 days following planting. No crop injury from PRE treatments was observed. Only slight injury was observed with some of the EP and MP treatments (data not reported). Excellent control (greater than 90%) of PA and CS was obtained with all treatments (Table 2). Keystone plus Hornet, Lumax, and Guardsman Max fb Status were the only treatments that resulted in less than 90% control of LC. Control of IM ranged from 23% to 88% with eight treatments giving 82% to 88% control. Grain yield was excellent; all treatments had much greater yield than the untreated check. A large variation in yield from plot to plot (LSD (0.05) of 42 bu/a) resulted in few significant differences with two treatments yielding lower than the others. Untreated check KRV-3 LSD (0.05) 11 6 8 1 PRE = preemergence (4/30), EP = early postemergence (5/29), MP = mid-postemergence (6/04). 2 LC = large crabgrass, PA = Palmer amaranth, CS = common sunflower, IM = ivyleaf morningglory. SOYBEAN HERBICIDE PERFORMANCE TEST Larry Maddux Summary This study was conducted at the Rossville Unit to compare preemergence herbicide treatments followed by glyphosate treatments. Control of large crabgrass (LC) was good to excellent with all but three treatments. All treatments gave excellent control of palmer amaranth (PA). All but one treatment resulted in excellent control of common sunflower (CS). Control of ivyleaf morningglory (IM) ranged from 80% to 90% for all but five treatments, one with 95% control and four with less than 80% control. There were no significant yield differences between treatments, although all yielded higher than the untreated check. Controlling weeds in row crops with chemical weed control and cultivation can reduce weed competition and, in turn, weed yields. Treatments in this study included an untreated check, nine preemergence (PRE) applications followed by glyphosate alone or with a tank mix partner, two treatments of two applications of glyphosate, and one treatment of only one application of glyphosate. Weeds evaluated in this test were LC, PA, CS, and IM. This test was conducted on a Eudora silt loam soil previously cropped to corn. The test site had a pH of 6.9 and an organic matter content of 1.1%. Corn stubble had been disked in the fall. No additional tillage was done prior to planting, and Midland soybean was planted no-till May 22 at 139,000 seeds/a in 30-in. rows with 10-34-0 fertilizer banded at 120 lb/a. Herbicides were broadcast at 15 gal/a with 8003XR flat fan nozzles at 17 psi. A randomized complete block design with three replications per treatment was used. PRE applications were made May 22 and included 22 oz/a Roundup WeatherMax plus KRV-4 ammonium sulfate (AMS) for a burndown. Early postemergence (EP) treatments were applied June 24 to 4-trifoliate soybeans; 1- to 4-in. LC, 3- to 8-in. PA, 4- to 10-in. CS, and 2- to 4-in. IM. Mid-postemergence (MP) treatments were applied July 3 to 5-trifoliate soybeans; 1- to 4-in. LC, 3- to 10-in. PA, 6- to 12-in. CS, and 2- to 5-in. IM. Late postemergence (LP) treatments were applied July 11 to 5- to 6-trifoliate soybeans, 1-in. LC, 4- to 12-in. PA, 6- to 14-in. CS, and 2- to 5-in. IM. All applications of glyphosate received 2.5 lb/a AMS, and the treatments with Flexstar, Fusilade DX, and SelectMax also received crop oil concentrate. Populations of all four weeds were moderate to heavy. Plots were not cultivated. Rainfall of 0.36 in. was received 2 days after PRE applications; an additional 1.51 in. was received within 2 weeks after planting. Plots were irrigated as needed and were harvested October 5 using a modified John Deere 3300 plot combine. Sufficient rainfall was received 2 days following planting to activate the PRE herbicides. Significant crop injury was observed from the PRE application of Boundary but not from any of the other PRE herbicides (data not shown). The EP application of Flexstar also resulted in some soybean injury. Table 3 shows weed control ratings made on July 23. Control of PA and CS was excellent for all treatments, except the MP Durango treatment resulted in only 70% control of CS. The LC control was good to excellent with only the Boundary fb Touchdown Total and Dual II Magnum fb by Flexstar plus Touchdown Total having less than 85% control. Control of IM was mostly in the 80% to 90% control range with three treatments having less than 80% control and one treatment having more than 90% control. All treatments had higher grain yields than the untreated check; there were no significant differences between treatments. Grain yield bu/a 33.8 59.9 KRV-5 LSD (0.05) 13 1 23 23 12.8 1 Postemergence treatments of glyphosate had ammonium sulfate added at 2.5 lb/a treatments with Flextar, Fusilade DX, and Select MAX had crop oil concentrate. 2 PRE = preemergence (5/22), EP = early postemergence (6/24), MP = mid-postemergence (7/03), LP = late postemergence (7/11). 3 LC = large crabgrass, PA = Palmer amaranth, CS = common sunflower, IM = ivyleaf morningglory. FUNGICIDES ON CORN Larry Maddux Summary Fungicide treatments were applied to corn at the tasseling (VT) growth stage at the Rossville Unit. No significant yield responses were observed in 2007. Fungicides have been shown to increase grain yield of corn in the presence of foliar diseases. Sometimes, increased yields have been observed even when diseases were not obvious. This study was conducted to evaluate the effects of several fungicides on grain yield of soybean. This test was conducted on a Eudora silt loam soil previously cropped to soybean. The test site had a pH of 7.1 and an organic matter content of 2.1%. Soybean stubble was disked and chiseled in the fall and field cultivated in the spring. Anhydrous ammonia was applied at 150 lb/a nitrogen (N). DeKalb DKC 63-74 YG Plus RR2 corn was planted May 1, 2007, at 29,600 seeds/a in 30-in. rows with10-34-0 fertilizer banded at planting. A randomized complete block design with four replications was used. Treatments included an untreated check, check with only nonionic surfactant, Headline at 6 and 9 oz/a, Headline at 4.5 oz/a plus Caramba at 4.5 oz/a, and Headline at 4.5 oz/a plus Trisert at 2 gal/a. Trisert is a 26% N foliar fertilizer solution. Treatments were applied at tasseling (VT) in 20 gal/a. Plots were sprinkler irrigated as needed and harvested on September 21 with a John Deere 3300 plot combine. Results are shown in Table 4. Corn yields varied among plots, and no significant differences were observed. Untreated check Nonionic surfactant check Headline Headline Headline + Caramba Headline + Trisert LSD (0.05) Rate ----6 oz/a 9 oz/a 4.5 oz/a + 4.5 oz/a 6 oz/a + 2 gal/a KRV-6 2007 yield (bu/a) 201 183 186 184 196 211 NS MACRONUTRIENT FERTILITY ON IRRIGATED CORN IN A CORN/SOYBEAN ROTATION Larry Maddux Summary The effects of nitrogen (N), phosphorus (P), and potassium (K) on a corn-soybean cropping sequence were evaluated from 1983 to 2007 (corn planted in odd years). Corn yield increased with increasing N rates up to 160 lb/a N, P fertilization resulted in corn yield increases 3 of the 13 years of this test, and K fertilization increased corn yield an average of 6 bu/a from 1983 to 1995 with no significant differences observed since. A study was initiated in 1972 at the Topeka Unit to evaluate the effects of N, P, and K on irrigated soybean. In 1983, the study was changed to a corn/soybean rotation with corn planted in odd years. Study objectives are to evaluate effects of N, P, and K applied to a corn crop on grain yields of corn and the following soybean crop and soil test values. The initial soil test in March 1972 on this silt loam soil showed 47 lb/a available P and 312 lb/a exchangeable K in the top 6 in. of the soil profile. Rates of P were 50 and 100 lb/a P2O5 (1972 to 1975) and 30 and 60 lb/a P2O5 (1976 to 2001) except in 1997 when a starter of 120 lb/a 10-34-0 (12 lb/a N plus 41 lb/a P2O5) was applied to all plots (also applied to soybean in 1998). Rates of K were 100 lb/a K2O (1972 to 1975), 60 lb/a K2O (1976 to 1995), and 150 lb/a K2O (1997 to 2001). Rates of N included a factorial arrangement of 0, 40, and 160 lb/a of preplant N (with single treatments of 80 and 240 lb/a N). The 40 lb/a N rate was changed to 120 lb/a N in 1997. Treatments were applied every year to KRV-7 soybeans (1972 to 1982) and every other year (odd years) to corn (1983 to 1995, 1999, and 2001). Corn hybrids planted were BoJac 603 – 1983; Pioneer 3377 – 1985, 1987, 1989; Jacques 7820 – 1991, 1993; Mycogen 7250 – 1995; DeKalb DKC626 – 1997, 1999; Golden Harvest H2547 – 2001; Pioneer 33R77 – 2003; DeKalb DKC63-81 – 2005; and Asgrow RX785 – 2007. Corn was planted in mid-April. Herbicides were applied preplant and incorporated each year. Plots were cultivated, furrowed, and furrow irrigated as needed through 2001 and sprinkler irrigated with a linear move irrigation system from 2003 to 2007. A plot combine was used to harvest grain. Average corn yields for the 13-year period from 1983 to 1995 (7 years) and yields for 1997 to 2007 are shown in Table 5. Yields were maximized with 160 lb/a N most years. Fertilization at 240 lb/a N did not significantly increase corn yield. From 1997 to 2007, corn yield with 120 lb/a N was not significantly different from that with 160 lb/a N and ranged from 0 to 8 bu/a less (LSD .05 was 13 to 19 bu/a). A yield response to P fertilization was obtained in 1985 and 1993 (yearly data not shown), but the 7-year average showed no significant difference in yield. No P response was observed in 1997 when starter fertilizer was applied to all plots. A significant yield response to P was obtained in 2003. Fertilization with K resulted in a significant yield increase in 1985, 1989, and 1993 (yearly data not shown), and the 7-year average showed a 6 bu/a yield increase. No significant corn yield response to K fertilization was observed from 1997 to 2007. 160 160 160 160 160 160 80 240 0 0 30 30 60 60 0 0 30 30 60 60 30 30 KRV-8 170 159 165 NS 0 127 160 154 160 160 158 164 60/150 133 159 165 162 159 163 165 LSD (.05) 6 NS NS NS NS NS NS 1 Fertilizer applied to corn in odd years 1983 to 2007 and to soybean for 11 years prior to 1983 (first number in each pair represents the rate applied to corn from 1983 to 1995). 2 P treatments were not applied in 1997. Starter fertilizer of 10 gal/a 10-34-0 was applied to all treatments in 1997 and 1998 (corn and soybean) N and K treatments were applied to corn in 1997. EAST CENTRAL KANSAS EXPERIMENT FIELD The research program at the East Central Kansas Experiment Field is designed to enhance the area's agronomic agriculture. Specific objectives are to 1) identify top performing varieties and hybrids of wheat, corn, grain sorghum, and soybean, 2) determine the amount of tillage necessary for optimum crop production, 3) evaluate weed control practices using chemical, nonchemical, and combination methods, and 4) test fertilizer rates and application methods for crop efficiency and environmental effects. Soils on the field=s 160 acres are Woodson. The terrain is upland and level to gently rolling. The surface soil is a dark graybrown somewhat poorly drained silt loam to silty clay loam over slowly permeable clay subsoil. The soil is derived from old alluvium. Water intake is slow, averaging less than 0.1 in./hr when saturated. This makes the soil susceptible to water runoff and sheet erosion. Precipitation during 2007 totaled 45.8 in., which was 9.02 in. above the 35-year average (Table 1). Most of the extra rainfall occurred from one day=s rainfall (6.56 in., June 30). Rainfall for June totaled 17.1 in. and exceeded the 35-year average by 11.89 in. Rainfall for July, August, and September was below average. August rainfall was 3.37 in. below average. The coldest days during 2007 occurred in January, February, and December with 13 days in single digits. The overall coldest day was 1.3°F on February 16. There was an exceptionally cold late spring freeze April 7 to 9 with temperatures dropping to 19.5°F. This caused serious freeze damage in wheat, alfalfa, and corn. There were 42 days during the summer of 2007 on which temperatures exceeded 90°F. The hottest 5day period was August 12 to 16 when temperatures averaged 102°F. The hottest day was August 14 when the temperature reached 103.5°F. The last freeze in the spring was April 9 (average April 18), and the first killing frost in the fall was November 1 (average October 21). The number of frost-free days was 205, more than the long-term average of 185. EVALUATION OF NITROGEN RATES AND STARTER FERTILIZER FOR STRIP-TILL CORN IN EASTERN KANSAS Keith A. Janssen Summary Effects of nitrogen (N) rates and starter fertilizer application on strip-till fertilized corn were evaluated at the East Central Kansas Experiment Field at Ottawa, Kansas, in 2006 and 2007. Under fairly dry growing conditions and following soybean both years, the 80 lb/a N rate optimized corn grain yields at approximately 95 to 110 bu/a. In 2006, starter fertilizer applied at planting increased earlyseason growth of strip-till fertilized corn compared with applying all of the starter in the strip-till zone but did not increase grain production. In 2007, when planting was delayed, neither early season corn growth nor grain yields were increased by starter fertilizer. Best grain yields were produced both years when all of the starter fertilizer nutrients (i.e., N, phosphorus (P), potassium (K); N-P-K) were included with the rest of the fertilizer in the strip-till zone. More years of testing are needed before reliable N rate recommendations can be made, and final decisions as to whether starter fertilizer is beneficial for strip-till fertilized corn are forthcoming. Corn growers in eastern Kansas might benefit from reducing traditional N rates when growing corn using an under-the-row, strip-till banded fertilization program. The high cost of N fertilizer demands prudent use. Research is needed to determine whether there is any yield benefit from applying starter fertilizer at planting with strip-till under-the-row fertilized corn. Research results can help determine whether strip-till corn producers may be able to lower N rates, refrain from purchasing costly planter fertilizer banding equipment, and not have to apply starter fertilizer at planting. Woodson silt loam soil at the East Central Kansas Experiment Field. Rates of N compared were 60, 80, 100, 120, 140 and 160 lb/a including a check. Starter fertilizer options evaluated included placement of all of the starter fertilizer 5 in. below the row during the strip-till operation, placement of the starter 2.5 in. to the side and 2.5 in. below the seed row at planting, and as a combination of half of the starter fertilizer applied in the strip-till zone and half at planting. In all cases, 30 lb/a N was included with the P and K starter fertilizers. Research by Barney Gordon at the North Central Experiment Field at Scandia, Kansas, showed that at least a 1:1 ratio of N-P fertilizer mix should be used for best starter P benefits. The experiment design was a randomized complete block with four replications. Soybean was grown prior to the corn studies each year. For preplant weed control, 1 qt/a atrazine 4L plus 0.66 pint/a 2,4-D LVE plus 1 qt/a COC were applied. Pioneer 35P17 corn was planted April 6, 2006, and May 19, 2007. Planting in 2007 was delayed because of wet weather. Corn was planted at 24,500 seeds/a in 2006 and 26,500 seeds/a in 2007. Preemergence herbicides containing 0.5 qt/a atrazine 4L plus 1.33 pint/a Dual II Magnum were applied the day after planting both years for weed control. Effects of the N rates and starter fertilizer applications on plant establishment were evaluated by counting all plants in the center two rows of each plot. Six whole plants were collected from each plot at the 6-leaf corn growth stage for the purpose of measuring treatment effects on early season growth. Grain yields were measured by machine harvesting and weighing grain from the center two rows of each 10-ft-wide × 40ft-long plot. Harvest was September 1, 2006, and September 20, 2007. This was the second year for this study. Six N rates and three starter fertilizer scenarios were evaluated for strip-till corn on an upland Moisture available for corn growth was below average in 2006 and 2007. Under these conditions and with corn following soybean, EC-2 the 80 lb/a N rate was sufficient for maximizing strip-till corn grain yields at approximately 95 to 110 bu/a (Table 2, Figures 2 and 4). In 2006, the application of starter fertilizer placed 2.5 in. to the side and 2.5 in. below the seed row at planting increased early growth of the corn by approximately 60% compared with placement of the starter in the strip-till zone. (Figure 1). The combination application of half the starter fertilizer applied at planting and half applied in the strip-till zone produced intermediate early season plant growth response. However, neither of these starter fertilizer applications increased grain yields. (Figure 2). Highest numerical grain yields were generally produced when all starter fertilizer nutrients (i.e., N-P-K) were included in the strip-till zone. It is hard to say whether this is because of improved late-season nutrient availability or less early season vegetative growth and moisture use. In 2007, when planting was delayed and weather during the early part of the corn growing season was warmer, starter fertilizer had no effect on early season growth or grain yield (Table 2, Figures 3 and 4). More years of testing under different growing conditions are needed before reliable N recommendations can be made and valid advice about benefits of starter fertilizer can be provided. This study will be repeated in 2008. 60-40-20 80-40-20 50 50-20-10 100-40-20 120-40-20 90 90-20-10 140-40-20 160-40-20 130 130-20-10 30-40-20 30-20-10 30-40-20 30-20-10 30-40-20 30-20-10 8 t 7 n la6 P /,g5 h t 4 w o r 3 G ly2 r a E1 0 10 ltn 89 a /P7 ,g 6 h t 5 w ro 4 ly 3 G ra 2 E1 0 95 /au 85 B l,d 75 e iY 65 55 45 105 95 /au 85 B l,d 75 e iY 65 55 45 May 19, 2007 Planting All Strip-till NPK Strip-till & Planter NPK Strip-till N plus Planter NPK 0 60 80 100 120 Fertilizer N Rates All Strip-till NPK Strip-till & Planter NPK Strip-till N plus all Planter NPK 80 100 120 Fertilizer N Rates Figure 2. Nitrogen rates and NPK starter fertilizer placement effects on yield of strip-till corn All Strip-till NPK Strip-till & Planter NPK Strip-till N plus Planter NPK All Strip-till NPK Strip-till & Planter NPK Strip-till N plus all Planter NPK 0 60 80 100 120 Fertilizer N Rates 140 160 0 Figure 4. Nitrogen rates and NPK starter fertilizer placement effects on yield of strip-till corn EVALUATION OF STRIP-TILL AND NO-TILL TILLAGE FERTILIZATION SYSTEMS FOR GROWING GRAIN SORGHUM PLANTED EARLY AND AT THE TRADITIONAL PLANTING TIME IN EASTERN KANSAS Keith A. Janssen and Gary L. Kilgore Summary Field studies were conducted at the East Central Kansas Experiment Field at Ottawa, Kansas, in 2006 and 2007 to evaluate how strip-till performed compared with no-till for growing grain sorghum planted early and at the traditional planting time. Nitrogen (N) rates and effects of starter fertilizer were also studied. None of the experiments showed differences in plant stands with strip-till compared with no-till, but air and soil temperatures when the sorghum was planted early in 2006 were very warm, which could have masked possible strip-till benefits. In 2007, when planting was in June, early season grain sorghum growth and yields were both increased with strip-till compared with no-till. Strip-till increased grain sorghum yields 3 to 6 bu/a on average. Number of days for sorghum to reach half-bloom stage was decreased slightly both years for strip-till compared with no-till. Application of starter fertilizer at planting had no effect on strip-till grain sorghum yields. In both years, 60 to 90 lb/a N optimized grain sorghum yields following soybean in both tillage systems. In Kansas, midsummer heat and drought are significant factors limiting grain sorghum production. Scheduling grain sorghum planting to avoid pollination and grain fill during this period is important. One strategy is to plant grain sorghum early to make better use of spring precipitation, cooler air temperatures, and lower evapotranspiration. Another strategy is to wait, store as much water in the soil profile as possible, plant grain sorghum in mid- to late June, and then rely on stored soil water and fall rains to produce the grain sorghum crop. Leaving crop residues on the soil surface and not tilling the soil can help retain valuable moisture. However, these practices, combined EC-5 with planting grain sorghum early, can be challenging. The extra residue can shade the soil and keep no-till field soils cool and wet longer in the spring. This can interfere with timely planting some years, result in poor plant stands, and slow early season grain sorghum growth. Consequently, use of no-till and early planting of grain sorghum has not been widely adopted. Strip-till, on the other hand, is a compromise conservation tillage system. This system includes some tillage, but only where seed rows are to be planted. Rowmiddles are left untilled and covered with crop residue for soil erosion protection and water conservation. This method of seedbed preparation also enables fertilizers to be precision applied under the row, minimizing the need to applying starter fertilizers at planting. Objectives of this study were to 1) evaluate strip-till and no-till tillage fertilization systems for growing grain sorghum planted early and at the traditional time, 2) determine N needs for sorghum when using these systems, and 3) determine whether there is any yield benefit from applying starter fertilizer at planting for strip-till fertilized grain sorghum. Field experiments were conducted in 2006 and 2007 at the East Central Kansas Experiment Field on an upland Woodson silt loam soil. Strip-till and no-till tillage systems were compared, and N rates ranging from 0 to 150 lb/a were tested. Also, effects of starter fertilizer placed 2.5 in. to the side and 2.5 in. below the seed row at planting was evaluated for strip-till fertilized sorghum. The sorghum experiments followed no-till soybean both years. For preplant weed control, 1 qt/a atrazine 4L plus 0.66 pint/a 2,4-D LVE plus 1 qt/a COC were applied. Pioneer 84G62 grain sorghum was planted April 14, 2006, (early planting) and May 24, 2006 (traditional planting). In 2007, early planting was not possible because of a prolonged wet spring. Instead, two hybrids (Pioneer 84G62 and 86G08) were planted in early June. Seed drop both years was 69,000 seeds/a. Preemergence herbicides containing 0.5 qt/a atrazine 4L plus 1.33 pint/a Dual II Magnum were applied both years at planting for additional weed control. Plant stands, early season grain sorghum growth, and grain yields were measured each year. Plant stands were evaluated by counting all plants in the center two rows of each plot. Early season grain sorghum growth was measured by collecting and weighing six plants from each plot at the 5- to 7-leaf growth stage, and grain yields were measured by machine harvesting the center two rows of each 10-ft-wide × 40-ft-long plot. Harvest was September 19, 2006, and October 10, 2007. Moisture was limiting both years. In 2006, there were no noticeable differences in plant stands between tillage systems for early planted sorghum (data not shown). However, air and soil temperatures at the early planting date in 2006 were unusually warm (80 to 90°F air temperatures and 60 to 70°F 4-in. depth soil temperatures), which could have masked any strip-till benefits. Overall, early season grain sorghum growth and grain yields were unaffected by tillage system in 2006 (Table 3). In 2007, when planting was in June, striptill increased early season growth and yields compared with no-till (Table 4). Grain yields were increased 3 to 6 bu/a on average. In 2006, days to half bloom ranged from 87 to 94 days after planting for early planted sorghum (July 10 to 17) and later planted sorghum (July 22 to 28), respectively. Number of days to half bloom for the later planted sorghum was only 10 to 12 days later then for the early planted sorghum, even though planting was 39 days later. Strip-till decreased the number of days to half bloom by approximately 1-2 days both years. Starter fertilizer applied at planting did not significantly improve grain yields compared with applying all starter in the strip-till zone either year. In both years, 60 to 90 lb/a N optimized grain sorghum yields. More years of testing are needed before reliable N rate recommendations can be made. Also, more years comparing strip-till and notill systems at different planting dates are needed before recommendations can be made regarding best tillage systems for planting grain sorghum early and at the traditional planting time. These studies will continue in 2008. Acknowledgments Financial support for this research was provided by the Kansas Grain Sorghum Commission. 11 11 NS 101 83 95 94 8.7 9.2 8.9 9.0 23 22 22 22 101 100 Treatment Tillage No-till No-till No-till No-till No-till Mean Strip-till Strip-till Strip-till Strip-till Strip-till Mean Fertilizer rate and placement 0-0-0 60-30-10, 2.5 in. × 2.5 in. at planting 90-30-10, 2.5 in. × 2.5 in. at planting 120-30-10, 2.5 in. × 2.5 in. at planting 150-30-10, 2.5 in. × 2.5 in. at planting 0-0-0 60-30-10, 5 in. below the row 90-30-10, 5 in. below the row 120-30-10, 5 in. below the row 150-30-10, 5 in. below the row Evaluation of Starter Strip-till 90-30-10, 5 in. below the row Strip-till 60-15-5 strip-till and 30-15-5 at planting Strip-till 120-30-10, 5 in. below the row Strip-till 90-15-5 strip-till and 30-15-5 at planting LSD (0.05) 9 8 9 9 3.7 4.2 3.5 3.4 92 93 7-leaf dry weight g 15.7 21.1 20.0 20.7 17.9 19.1 18.3 24.0 23.0 19.8 21.8 21.4 Pioneer 86G08 Planted June 11 Half bloom date Aug. 13 10 10 10 11 11 13 9 10 10 9 10 23.0 22.2 19.8 23.9 9 10 10 9 75 76 PLANTING DATE, HYBRID MATURITY, AND PLANT POPULATION EFFECTS ON CORN Larry Maddux Summary Three planting dates, three corn hybrid maturities, and three plant populations were evaluated in 2006 and 2007 near Ottawa, Kansas. Silking dates were the same for the first two planting dates and about 8 days later for the third. The 105-day hybrid silked 3 days after the 100-day hybrid in both years, and the 113-day hybrid silked 5 and 7 days afterward in 2006 and 2007, respectively. Grain test weight decreased slightly after the April 1 planting date and also decreased as hybrid maturity increased in 2006 but not in 2007. Grain yields were not significantly different (P < .05) in 2006, but the highest yield was obtained with the 105-day hybrid planted on March 29. Highest yields were also obtained with the 105-day hybrid planted on April 5 in 2007. No consistent differences between plant populations were observed. During the past few years, corn acreage in east central Kansas has increased. This study was designed to evaluate three planting dates, three plant populations, and three corn hybrids of varying maturities. Three Pioneer corn hybrids of different maturities were planted in 2006 and 2007 on a Woodson silt loam at the East Central Kansas Experiment Field: 38H66 (105 day), 35P80 (110 day), and 33B49 (113 day). Seed was planted at 19,800, 24,200, and 28,600 seeds/a in an effort to obtain final populations of 18,000, 22,000, and 26,000 plants/a. Planting dates of March 15, April 1, and April 15 were attempted. Actual planting dates in 2006 were close, March 13, March 29, and April 13. In 2007, the first planting was made March 19. Unseasonable warm weather resulted in faster emergence than in 2006, and an extreme cold spell on April 7 and 8 resulted in 100% loss of the corn. The second planting date in 2007 was April 5, and the third planting date was delayed by wet weather until May 16. The first planting date was replanted June 7. Fertilizer (120-30-30) was applied with a strip-till applicator prior to planting. Recommended herbicides were applied for weed control. Plots were harvested with a JD 3300 plot combine. Results Plant populations obtained were close to the desired populations both years (data not shown). Emergence of corn planted March 13, 2006, was only 3 days before that of corn planted March 29, and these plants reached 50% silking on approximately the same dates (Table 5). Corn planted on the third planting date reached 50% silking about 8 days later. Hybrid 35P80 silked 3 days later than 38H66, and 33B49 reached silking another 2 days later than that. In 2007, corn planted March 19 emerged quickly and was killed by cold weather. The second planting date (April 5) was the only one close to the proper date; the third planting date was delayed by wet weather until May 16, and the first planting date was replanted on June 7. Hybrids planted on the second planting date in 2007 reached 50% silking similar to corn planted on the second planting date in 2006 (planted 5 days later and silked 3 to 5 days later). Corn from the third planting date and the replanted first planting date were silking in mid- to late July under considerable moisture stress. Test weight decreased as planting date was delayed after the April 1 planting date, especially in 2007 with the two later planting dates. In 2006, test weight also tended to decrease as hybrid maturity increased, but this was not observed in 2007. Grain yields were not significantly different (P < .05) in 2006, although corn from the March 29 planting date had the highest yield, and corn from the April 13 date had the lowest yield. In 2007, yields were higher from the April 5 planting date and higher than in 2006 but decreased with delayed planting; corn planted June 7 yielded less than half that of corn planted April 5. No significant differences in yields between hybrids or plant populations were observed in 2006. However, populations of 22,000 and 26,000 plants/a tended to yield higher at the early planting date, whereas 18,000 plants/a tended to yield higher at the April 13 planting date. In 2007, PI 35P80 yielded higher than the other two hybrids, and no consistent response to plant population was observed. 3/13/06 6/07/07 3/13/06 6/07/07 3/13/06 6/07/07 3/29/06 4/05/07 3/29/06 4/05/07 3/29/06 4/05/07 4/13/06 5/16/07 4/13/06 5/16/07 4/13/06 5/16/07 Planting date means: 3/13/06; 6/07/07 3/29/06: 4/05/07 4/13/06; 5/16/07 Hybrid (Pioneer) 38H66 35P80 33B49 38H66 35P80 33B49 38H66 35P80 33B49 Hybrid Means: 38H66 35P80 33B49 50% Silking 2006 2007 Days after June 1 19 53 19 54 19 54 21 56 21 57 22 56 23 61 23 62 24 62 19 21 20 21 20 21 21 25 22 25 22 25 23 28 23 28 24 28 27 41 25 42 25 42 27 44 28 44 29 44 32 47 32 47 33 47 57 25 44 39 42 46 42 42 42 EC-10 21 21 29 21 24 26 24 24 24 Test weight 2006 lb/bu Yield 58.0 58.6 58.2 56.8 57.2 56.8 56.7 57.1 57.2 58.0 58.4 58.4 57.1 57.9 57.5 57.4 57.2 57.4 55.5 55.5 55.8 55.5 55.6 55.4 55.2 54.4 54.7 57.4 57.7 55.3 57.4 56.6 56.4 55.1 55.3 55.9 92 106 107 95 96 93 93 100 103 103 110 108 104 108 100 103 100 102 88 89 91 100 93 95 92 89 93 98 104 92 99 98 97 97 99 99 64 62 58 66 60 60 53 39 43 118 111 119 130 128 146 115 123 123 95 101 92 111 96 93 97 98 101 56 124 98 91 99 88 94 91 93 FIELD Copyright 2009 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, give credit to the author(s), Agronomy Field Research 2008, Kansas State University, April 2009. Contribution no. 09-208-S from the Kansas Agricultural Experiment Station. Chemical Disclaimer Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. Experiments with pesticides on nonlabeled crops or target species do not imply endorsement or recommendation of nonlabeled use of pesticides by Kansas State University. All pesticides must be used consistent with current label directions. Current information on weed control in Kansas is available in 2009 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland, Report of Progress 1007, available from the Distribution Center, Umberger Hall, Kansas State University, or on the World Wide Web at: www.ksre.ksu. edu/library (type Chemical Weed Control in search box). Publications from Kansas State University are available on the World Wide Web at: www.ksre.ksu.edu Kansas State University Agricultural Experiment Station and Cooperative Extension Service SRP 1011 30- year avg.


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