bluuebunny/crossref_metadata_2025 huggingface dataset:
Residue Management in Double‐Crop Conservation Tillage Systems1
Authors: Langdale G. W. , Hargrove W. L. , Giddens Joel
Published: July 2010

Crop residues have become an increasingly important renewable natural resource. They can serve to maintain optimum crop production on the nation's severely eroding 45.3 million ha of cropland as well as decrease the increasing cost of synthetic N fertilizer. Conservation tillage technologies have been recently identified as a high priority research need for sustaining agronomic productivity in the humid USA. Three double‐crop tillage systems—spring and fall disking, fall disking, and no‐tillage—were evaluated for 4 years on a Southern Piedmont Ultisol (Cecil sandy loam—a clayey, kaolinitic, thermic Typic Hapludults). These tillage systems were considered conventional (CT), minimum (MT), and continuous no‐till (NT), respectively. Wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench] were used in the double‐crop systems as high stover producing as well as medium N fertilizer requiring crops. Six orthogonal N fertilizer rates ranging from 0 to 250 kg ha−1 were imposed on each tillage system. Both conservation tillage systems (MT and NT) were manageable in the short term (1 or 2 years) and produced significantly more sorghum grain than the conventional system. Grain yields (4 years) and favorable soil fertility status suggest the MT system was the best double‐crop management system in the long range (>2 years). The sum of wheat and sorghum grain yield increased significantly (5.0 to 7.4 Mg ha−1 year−1) in a linear manner with stover up to 11.5 Mg ha−1 year−1. This suggests some crop use of the 62 kg N ha−1 year−1 returned to the land in stovers when N fertilizers were applied at the recommended rate (100 kg N ha−1 year−1). It appears that N fertilizer rates may be reduced progressively in small quantities for optimum double‐crop yields in longterm conservation tillage systems on Southern Piedmont lands.
Response of Proso Millet to Fungicide Seed Treatments1
Authors: Nelson L. A. , Kerr E. D.
Published: July 2010

Fungicidal seed treatments are recommended in many crops as a prophylaxis because of their low cost and possible benefits. The purpose of this study was to determine if there was a beneficial effect from treating proso (Panicum miliaceumL.) seed with fungicides before sowing. Three tests were conducted near Sidney, NE on Mesic Aridic Argiustoll soil. The first 2‐year trial compared the influence of several seed treatment fungicides on proso emergence and grain yield, using a widely accepted planting method. Plant emergence and grain yield was not improved by any of the fungicide treatments. The second 2‐year trial compared two seed treatment fungicides and a check, using planting equipment that gave good and poor seedbeds. Again, fungicides did not improve stand or grain yield regardless of the quality of the seedbed. The third trial of 3 years duration investigated the effects of seed treatment fungicides on preventing head smut caused by Sphacelotheca destruens, a seedborne pathogen of proso. Seed treatment with captan {N‐[(trichloromethyl)thio]‐4‐cyclohexene‐1,2‐dicarboximide}, thiram [tetramethylthiuram disulfidel, and maneb {manganese ethylenebis[dithiocarbamate]} were effective in reducing head smut infection by 93% over the untreated plots.
Response of Spring Wheat to N Fertilizer Placement, Row Spacing, and Wild Oat Herbicides in a No‐Till System1
Authors: Reinertsen M. R. , Cochran V. L. , Morrow L. A.
Published: July 2010

A 2‐year study was conducted on a north facing Thatuna silt loam (fine‐silty, mixed, mesic Xeric Argialbolls) to evaluate the influence of N fertilizer placement, crop row spacing, and wild oat (Avena fatuaL.) herbicides on wild oat populations and wheat (Triticum aestivumL.) yield in no‐till spring wheat. The treatments were factorial arrangements of ammonium nitrate either surface applied preplant or banded 50 mm below the crop seed at planting; wild oat control using triallate [S‐(2,3,3‐trichloroallyl)diisopropylthiocarbamate]pre‐emergence, difenzoquat [1,2‐dimethyl‐3,5‐diphenyl‐1H‐pyrazolium] post‐emergence, or no herbicide (check); and crop row spacings of either 200,300, or 400 mm. Surface‐applied fertilizer N significantly increased wild oat populations compared with banding the N fertilizer below the seed, but had no effect on dry weight or N uptake. Banded N increased total dry weight N uptake, and grain yields of wheat. These responses indicate that banded fertilizer N was positionally more available to wheat than was broadcast N, but banding N did not reduce availability of N to wild oat. However, surface‐applied N stimulated wild oat emergence. Triallate decreased wild oat populations compared to difenzoquat or no herbicide, but was no more effective than difenzoquat in reducing wild oat dry weight and total Kjeldahl N uptake. Both herbicides reduced wild oat dry weight as compared to the no herbicide check and significantly increased wheat yields. Row spacing did not affect wild oat dry weight or total N uptake, but the 200 m row increased wheat dry weight, total Kjeldahl N uptake, and grain yields compared to the 300 and 400 cm rows. There were no significant interactions.
Quality of Orchardgrass Hay Ammoniated at Different Rates, Moisture Concentrations, and Treatment Durations1
Authors: Moore K. J. , Lechtenberg V. L. , Hendrix K. S.
Published: July 2010

Mature grass hays are generally characterized by low fiber digestibility and low protein concentration. Research is needed to determine how various treatment conditions influence changes in nutritive value obtained by ammoniating mature grass hay. The objectives of this study were to determine the effects of NH3 application rate, hay moisture concentration, and treatment duration on the chemical composition and digestibility of a mature orchardgrass (Dactylis glomerata L.) hay. Hays reconstituted to moisture concentrations of 100, 300, and 500 g kg−1 wet weight (WW) were treated with NH3 at rates of 12, 24, or 36 g kg−1 dry weight (DW) in 2‐L enclosed containers. The containers were aerated after treatment durations of 7, 21, or 63 days. All treatments were in factorial combination. In another experiment conducted similarly, hay with a moisture concentration of 200 g kg−1 WW was treated with NH3 at rates up to 144 g kg−1 DW for 21 days. Increases in the in vitro digestibility of all constituents were largest for hay with a moisture concentration of 300 g kg−1 WW. Treatment of this hay with NH3 at 36 g kg−1 DW increased (P <0.01) the in vitro digestibility of neutral detergent fiber (NDF) by 227 g kg−1, acid detergent fiber by 265 g kg−1, cellulose by 293 g kg−1, and hemicellulose by 186 g kg−1. No further increase in NDF digestibility occurred when NH3 was applied at rates greater than 36 g kg−1 DW (P >0.01). The proportion of the total increase in NDF digestibility after 7 and 21 days was 75.0 and 96.3%, respectively, for hay with a moisture concentration of 300 g kg−1 WW treated with NH3 at 36 g kg−1 DW. Ammoniation at 36 g kg−1 of hay with moisture concentration of 500 g kg−1 WW increased (P <0.01) the concentrations of total N, ammonium N, and acid detergent insoluble N by 29.9, 15.1, and 1.8 g kg−1 DW. The proportion of the total N added that was retained by the hay 63 days after treatment averaged 65.0, 85.2, and 99.4% for hay with moisture concentrations of 100, 300, and 500 g kg−1 WW, respectively. The proportion of the added N retained in the ammonium form for these hays averaged 39.1, 51.6, and 59.3%. Ammoniation at 36 g kg−1 DW decreased (P <0.01) the concentration of hemicellulose by as much as 70 g kg−1 DW in hay with a moisture concentration of 500 g kg−1 WW. The concentrations of other fiber constituents were not affected by ammoniation. These results indicate that the fiber digestibility of low quality orchardgrass hay can be greatly increased by treatment with NH3 at 36 g kg−1 DM. The increase in digestibility occurs over a wide range of hay moisture concentrations and can be obtained using relatively short treatment durations.
Effect of Subsurface Amendments and Irrigation on Alfalfa Growth1
Authors: Rechcigl J. E. , Reneau R. B. , Starner D. E.
Published: July 2010

Aluminum toxicity is a major cause of low yields and reduced longevity of alfalfa (Medicago sativa L.) in many areas. This research investigated the effectiveness of subsurface placement (30 cm) of 22 400 kg ha−1of dolomitic lime and varying rates of P and K fertilizer on alfalfa yield. A Davidson clay loam (clayey, kaolinitic, thermic Rhodic Paluedult) soil had subsurface amendments applied 8 years (1969) prior to seeding ‘Arc‘ alfalfa. Yields from 1978 through 1982 increased with plowsole application of lime regardless of irrigation. In 1981, the average increase in yields due to liming was 6.7 and 2.2 Mg ha−,1 while in 1982 the yield increases averaged 4.5 and 3.5 Mg ha−,1 with and without irrigation, respectively. Soil exchangeable AI was reduced and pH and root lengths were increased by plowsole lime. These data indicate that plowsole application of lime in acid soil can increase alfalfa yields.
Selective Control of Tall Fescue in Kentucky Bluegrass with Chlorsulfuron1
Authors: Larocque D. J. , Christians N. E.
Published: July 2010

Tall fescue (Festuca arundinacea Schreb.) often occurs as a troublesome weed in Kentucky bluegrass (Poa pratensis L.) turf. There is no labeled selective control for it, because of the physiological similarity of the two species. The objective of this study was to investigate the use of chlorsulfuron {2‐chloro‐N‐[(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)aminocarbonyl]‐benzenesulfonamide} as a possible selective control of tall fescue in Kentucky bluegrass. Chlorsulfuron was applied in two greenhouse studies to ‘Baron’ Kentucky bluegrass and ‘Kentucky 31’ tall fescue in single application rates of 18, 35, 71, 141, 212, and 282 g (a.i.) ha−1 and split application rates of 18 + 18, 35 + 35, 71 + 71, 141 + 141, and 212 + 212 g a.i. ha−1 which were applied at a 2‐week interval. The experiment was conducted as a split‐plot with the two species as main plots and the 12 chlorsulfuron treatments as subplots in four replications. The tall fescue was damaged by a single application rate of 71 g ha−1 and a split application rate of 71 + 71 g ha−1, and percentage control was observed to be 78 to 95% at application rates of 282 g ha−1 and above. Kentucky bluegrass showed a much greater tolerance to chlorsulfuron treatments, with little effect at the 282 g ha−1 single application rate and only minor damage at the 212 + 212 g ha−1 split application rate in both experiments. The results indicate that chlorsulfuron has the potential for use as a selective‐postemergence control of tall fescue in Kentucky bluegrass turf.
A Microecosystem for Fertilizer and Pesticide Fate Research1
Authors: Branham B. E. , Wehner D. J. , Torello W. A. , Turgeon A. J.
Published: July 2010

A microecosystem was designed to study the behavior of pesticides, fertilizers, or related compounds applied to plant stands. The system consists of three parts: a brass base that holds the plant growth media, a glass atmospheric chamber that rests on the base, and a set of analytical traps. The brass base is fitted with a porous ceramic plate so that tension can be applied to the water in the growing media. Air enters the bottom of the glass atmospheric chamber and exits through the top into appropriate trapping systems to recover volatilized pesticides, ammonia, or metabolized 14CO2 from labeled compounds. A port at the base of the chamber allows collection of leachate. The microecosystem was evaluated by applying N sources or a pesticide to intact turfgrass profiles and monitoring the fate of the applied compound. Leaching and volatilization losses of N ranged from 0 to 17% and 0.1 to 17% of the applied N, respectively,, depending on N source, soil conditions, and whether tension was: applied to the base of the system. Three weeks after the application of radiolabeled diazinon [0,0‐diethyl‐0‐(2‐isopropyl‐4‐metnyl‐6‐primidinyl) phosphorothiote] to a turf, 47% of the label remained in the form of the parent compound, 22% had been metabolized and lost as 14CO2,1% had leached through the profile, 2% had been lest through volatilization, and 28% remained in the soil as a metabolite or in unextractable compounds. The microecosystem has proven to be an invaluable tool for turfgrass research and should be useful for fertilizer and pesticide fate studies with other crops.
Nitrification Inhibitor Evaluation on Cotton. I. Rate and Time of N Application1
Authors: York A. C. , Tucker M. R.
Published: July 2010

Most cotton (Gossypium hirsutum L.) in the southeastern USA is grown on sandy soils that are subject to extensive N leaching. Split applications of N are normally utilized to reduce leaching losses. Even with split applications, however, leaching can still subject the crop to periods of N deficiency which can lead to yield reductions. Experiments were conducted at three sites (Typic and Plinthic Palendults soils) in 3 years to determine if at‐planting application of a nitrification inhibitor (NI), either etridiazol [5‐ethoxy‐3‐(trichloromethyl)‐l,2,4‐thiadiazole] or nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine], would allow for reduced N application rates and/or eliminate the need for split N applications. Urea was incorporated at three rates (65,100, and 135 or 45,90, and 135 kg N ha−1), either all applied at planting or as a split application with 22 kg N ha−1 at planting and the remainder sidedressed at the early square stage. Etridiazol or nitrapyrin, each at 0.56 kg ha,−1 was incorporated with the at‐planting urea. Leaf N content at the early square and peak flowering stages, stand counts, lint yield, and fiber length and micronaire were recorded. Neither NI affected lint yield, fiber length, or micronaire. Etridiazol reduced stands 6% and increased leaf N content 9% at the early square stage at one of three sites. Nitrogen application rates and N application time did not affect fiber length or micronaire. Increasing N application rates reduced stands when all N was applied at planting. Yield response to N application rates and N application time varied by location and appeared to be related to rainfall patterns and N carryover from previous crops. Neither NI affected crop response to N application rates or N application time.
Physiological Response of Meadowfoam to Crop Water Deficits1
Authors: Pearson C. H. , Jolliff G. D.
Published: July 2010

Meadowfoam (Limnanthes alba Benth.), a new oilseed crop, is adapted to wet meadows in its native habitat. The effect of plant water stress during seed development has not been reported, but was postulated as a cause of seed yield variation in cultivated fields. The objective of this field study was to characterize meadowfoam response to water stress. Treatments included: No irrigation (control); early irrigation, during May (El); and continued irrigation, from the 1st week of May until crop maturity (CI). They were applied in a randomized complete block experimental design on a Woodburn silt loam soil (flne‐silty, mixed mesic Aquultic Argixerolls) in 1981 and 1982. Plant water potential Ψ, turgor potential (Ψp), osmotic potential (Ψπ), stomatal resistance (R), transpiration (Tr), and canopy temperature (CT) were measured at 0600, 0900, 1200, 1500, and 1800 h on several days during flowering and seed development. Differences between treatments for Ψ, Ψp, Ψπ R, Tr, and CT were not apparent in 1981, probably because above average precipitation occurred during May and June keeping all treatments moist. However, these data were useful to characterize physiological responses of meadowfoam due to changes in plant age and environmental conditions during a season when soil water deficits were not severe. Generally, crop water deficits were greatest and Tr was highest at 1500 h, and R was highest at 1800 h. In contrast to many other crop species, meadowfoam maintained an unusually high Ψ which did not drop below −0.8 MPa. The amount of precipitation during flowering in 1982 was the lowest in 16 years. At mid‐flowering after 1200 h the control plants had higher crop water deficits, higher R, lower Tr, and slightly higher CT than the irrigated plants. These responses became progressively greater by late flowering and early seed fill. Crop water stress in the El treatment was slight at mid‐and late flowering, but became greater at early seed fill. During a typical day Ψp decreased in response to lower Ψ with less than 0.2 MPa decrease in Ψπ. The control had an Ψπ that was only 0.07 MPa lower than the irrigated treatments. Adaptation of meadowfoam to crop water stress by lowering Ψπ was minimal. Stomatal closure occurred between a Ψ of −0.5 to −0.7 MPa. The CT of the control at mid‐flowering, late flowering, and early seed fill averaged 0.4, 1.0, and 2.3 °C higher than the CI treatment, respectively. Canopy temperatures of the El treatment at early seed fill averaged 0.8°C higher than the CI treatment. The results indicated that meadowfoam requires a high Ψ for growth and development, and its tolerance to crop water deficits is low.
Influence of Soil Compaction on Trifluralin Phytotoxicity to Corn1
Authors: Martin Andrew G. , Jordan Thomas N. , Steinhardt Gary C.
Published: July 2010

Little work has been published in the United States on the influence of soil compaction on increased herbicide phytotoxicity to crop seedling development. Yet, soil compaction on agricultural lands is an increasing problem, especially on certain soil types in the eastern Corn Belt region of the nation. In greenhouse studies, the effects of soil compaction of an Ockley silt loam (fine, silty, mixed, mesic Typic Hapludalf) treated with trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) were determined on the root and shoot development of corn. The compaction was established by compacting to the desired bulk densities 750 g soil in 600 mL stainless steel pots with a hydraulic press. Three rates of trifluralin (0, 0.38, and 0.79 µmol kg−1) reduced secondary root development by 60% as the bulk density increased up to 1.66 g cm−3. Visual ratings of the characteristic swollen root tip injury indicated that increasing the soil bulk density from 1.50 to 1.66 g cm−3 resulted in an increased number of malformed roots at all herbicide rates. When compaction was made throughout the entire soil profile, the average day for emergence increased from 5.0 to 6.2 days as bulk densities increased from 1.10 to 1.66 g cm−3.
The Residual Effect of P and Lime on the Performance of Four Tropical Grasses in a High P‐fixing Oxisol1
Authors: Couto Walter , Leite Gilberto G. , Kornelius Euclides
Published: July 2010

Pastures sown after several years cropping may take advantage of the residual lime and P fertilizers applied earlier. A field experiment was conducted to (i) compare the potential of different grasses to use previously applied P fertilizer at two levels of applied lime and (ii) evaluate the capacity of two soil tests to predict P availability to grasses. Four grasses [Andropogon gayanusvar. bisquamulatus (Hochst) Hack] cv. Planaltina; Panicum maximumcv. Makueni; P. maximumvar. trichoglume cv. Green panic and Setaria ancepscv. Kazungula were sown on an old experimental site where P fertilizers and lime have been applied over a period of 6 years for total rates of 0, 44, 87, 131, and 175 kg ha−1of P and 4 Mg ha−1of lime. Despite the well‐known P‐fixing capacity of the soil (clayey, kaolinitic, isohyperthermic, Typic Haplustox), grasses responded markedly to residual P and lime. Andropogon and to some extent Setaria performed better than the other grasses in both, limed and unlimed plots, at low levels of applied P. Makueni performed well only on limed plots at high levels of applied P (175 kg ha−1). Available soil P and dry matter yield correlated well but the range of P availability was too small for prediction purposes. It was concluded that despite high P‐fixing capacity a large portion of residual P remained available to grasses. Soil test procedures should be improved to better reflect the P availability to grasses.
Shade During Growth—Effects on Chemical Composition and Leaf Color of Air‐Cured Burley Tobacco1
Authors: Andersen R. A. , Kasperbauer M. J. , Burton H. R.
Published: July 2010

Development of off‐color in air‐cured burley tobacco (Nicotiana tabacumL.) leaf may adversely affect the quality and value of the crop. Shading from other vegetation during growth may be a contributing factor. The purpose of this investigation was to determine the effects of shading during field growth on leaf color and chemical composition of air‐cured burley tobacco. Whole leaves and lamina from air‐cured burley tobacco (cv. Kentucky 14) grown under 0,45, or 65% shade (reduced light) conditions in field (Maury silt loam soil; clayey, mixed, mesic, Typic Paleudalf) experiments were quantitatively analyzed for parameters of color (determined by reflectance), chlorophyll isomers, carotenoids, brown pigment, total phenols, total alkaloids, and nitrate‐N. Whole leaves and lamina from tobacco grown under increased shade generally had more red hue, less yellow hue, less brightness, and more total color change. Lamina from tobacco grown under increased shade had higher levels of chlorophyll a, chlorophyll b, lutein, β‐carotene, neoxanthin, violaxanthin, and nitrate‐N, but lower contents of brown pigment and total alkaloids. Whole leaf grown under increased shade had generally higher contents of nitrate‐N and lower brown pigment, total phenols, and total alkaloids. The color changes in air‐cured whole leaf and lamina associated with increased shade during growth support the hypothesis that shade is one causative factor for the undesirable “pink leaf” characteristic that sometimes develops in air‐cured burley tobacco, although the data do not show that it is the only factor involved.
A Versatile, Inexpensive Microcomputer‐Based Leaf Area Measurement System1
Authors: Clarke John M. , McCaig Thomas N.
Published: July 2010

An inexpensive electro‐optical system was developed and evaluated for measuring leaf areas. The system consisted of a standard optical lens and circuitry to digitize images, and was interfaced with a microcomputer. Software was developed to measure total leaf areas or differential green, chlorotic, and total areas. Cost of the system, excluding the microcomputer, was under $450. The system provided accurate measurements of leaf area when the lens was positioned so that leaves being measured occupied > 5% of the useable image area.
Cassava‐Cowpea and Cassava‐Peanut Intercropping. III. Nutrient Concentrations and Removal1
Authors: Mason S. C. , Leihner D. E. , Vorst J. J.
Published: July 2010

Little is known about the influence of intercropping cassava (Manihot esculentaCrantz) with cowpea [Vigna unguiculata(L.) Walp] or peanut (Arachis hypogueaL.) on nutrient concentrations of plant tissue or nutrient removal by the crops. The objectives of this study were to (i) compare the nutrient concentrations in plant parts of cassava, cowpea, and peanut in intercropping systems to those in sole cropping systems, and (ii) determine uptake of N, P, and K of cassava‐cowpea and cassava‐peanut intercropping systems as compared with the sole cropping systems. Cassava, cowpea, and peanut were grown as sole crops and intercrops on a Typic Dystropept soil at Santander de Quilichao, Colombia, in 1981 and 1982. Intercropping with cowpea resulted in 0.8, 0.6, and 0.3 g kg−1lower P concentration [P], and 5.2,4.9, and 2.9 kg 1lower [N] in cassava stems, leaves, and storage roots, than resulted from sole‐cropped cassava 50 days after planting. Intercropping had no influence on [N], [P], and [K] of cassava at later harvest dates or of cowpea at any harvest date. Similar results occurred when cassava was intercropped with peanut, although peanut was a less vigorous competitor with cassava for P than was cowpea. The cassava‐cowpea and cassava‐peanut intercropping systems removed 3.0 to 7.5 g m 2more N, 0.30 to 0.47 g m 2more P, and 2.5 to 5.1 g m more K than sole‐cropped cassava. Results suggest that these intercropping systems remove more nutrients than comparable sole crops, which leads to more rapid mining of natural soil fertility or the need for higher fertilizer application rates.
A Microcomputer‐Controlled Leafweighing System1
Authors: McCaig T. N.
Published: July 2010

A completely, automated weighing system was built to facilitate large numbers of repetitive wheat‐leaf weighings required in a drought program (wheat: Triticum aestivumL.). Leaf samples (up to 265) were clipped to holders suspended from hangers on a conveyor chain. The samples were then repetitively weighed (three samples per minute) throughout the day to determine individual water‐loss rates. An inexpensive microcomputer controlled all operations including movement of the conveyor chain, transfer of samples to and from the balance, taring and weighing operations, and data storage. With minor modifications this weighing system can be easily applied to other types of routine weighing needed in agricultural research.
Response of Corn to Tillage and Delayed Irrigation1
Authors: Porro I. , Cassel D. K.
Published: July 2010

Irrigation in humid regions is often delayed based on forecasted rainfall or due to labor shortages or equipment problems. The effects of tillage and delayed irrigation on corn (Zea mays L.) were investigated in 1982 and 1983 on a Norfolk loamy sand (Typic Paleudult) with a tillage pan. Irrigation treatments were: optimum irrigation when tensiometer measured soil water pressure at the 25‐ or 30‐cm depth was −40kPa; 2‐day and 4‐day delays after irrigation was needed; and a nonirrigated control. Each irrigation treatment was superimposed on land prepared by two tillage treatments: (i) conventional and (ii) subsoiling and bedding. Delayed irrigation during a wet growing season (1982) had little effect on corn growth. Delayed irrigation during the dry growing season (1983) reduced plant height, leaf area, biomass, and grain yield on conventionally tilled soil but only grain yield on subsoiled plots. With a 4‐day irrigation delay, grain yields were reduced 29% below the 10.22 Mg ha−1 yield for conventional tillage but only 11% below the maximum of 10.56 Mg ha−1 for subsoiling. Irrigation in 1982 increased mean grain yield of all three delay treatments by 23 and 1% for conventionally tilled and subsoiled treatments, respectively. In 1983, these increases were 314 and 18%, respectively. A 1‐yr subsoiling carryover (1983) resulted in a yield of 8.89 Mg ha−1 vs. a current‐year subsoiled yield of 10.68 Mg ha−1. A 2‐yr carryover (1982) resulted in a yield of 9.60 vs. 10.60 Mg ha−1 from current year subsoiling.
Studies of Intact Shoot‐Root Systems of Field‐Grown Winter Wheat. I. Sampling Techniques1
Authors: Belford R. K. , Rickman R. W. , Klepper Betty , Allmaras R. R.
Published: July 2010

The yield component most closely related to wheat (Triticum aestivum L. em. Thell.) yield in the dryland farming area of the Pacific Northwest is heads per unit area. Tiller survival determines the head population and is therefore a major yield determining factor. A study relating tiller survival to tiller rooting required a sequential sampling of intact shoot‐root systems of field grown plants. As no technique to provide the required samples was found in the literature, a new procedure was devised. Square metal tubes, 0.18 by 0.18 by 1.1 m with removable side, were constructed of 16‐gauge steel. These tubes were forced into the ground with a hydraulic coring machine immediately after emergence of winter wheat (var ‘Stephens’) planted in 0.18‐m rows on 14 Oct. 1981 in field plots on a Walla Walla silt loam (mixed, mesic Typic Haploxerolls). Thermocouples and tensiometers at 0.2‐, 0.4‐,0.6‐, and 0.8‐m depths showed that soil temperatures were not significantly different between the tubes and adjacent field soil, but soil in some tubes was significantly wetter (higher water potential) than adjacent field soil during winter. Tubes were extracted from the field on 23 February, 17 March, 19 April, and 1 June. The removable side was taken off and a fine spray was used to wash soil from the roots. Washed intact plants were floated in water in a shallow tray to separate individual plants, tillers, and their associated roots. These separations were not successful for deep roots for the June sampling date. This technique permits collection of data on rooting habits of plants at different times in the growing season, on associations between shoots and intact field‐grown root systems, and on details of root branching patterns under field conditions.
Nitrogen Fertility and Sucker Control Method on Maryland Tobacco Yield, Value, and Quality1
Authors: Bruns H. A.
Published: July 2010

The quality of Maryland tobacco as influenced by N fertility and sucker‐control method is not well documented. Four N‐fertility rates (67.2, 134.4, 201.6, and 268.8 kg ha−1 N) along with five methods of sucker control [topped nonsuckered, topped handsuckered, KMH (K salt of 1‐2‐dihydro‐3,6‐pyridazinedione‐meleic hydrazide), Prime + {2‐chloro‐N‐[2‐dinitro‐4‐(trifluoromethyl)‐phenyl]‐N‐ethyl‐6‐fluorobenzenemethanamine}, and OST‐85 (1‐decanol plus 1‐octanol mixture)] were imposed on the tobacco (Nicotiana tabucum L.) cultivar MD 609 in 1983 and 1984. Yield, value, burn duration, filling capacity, total alkaloids of cured leaf, plus NO3‐N and total N at topping, harvest, and after curing were evaluated. Drought during July 1983 adversely affected most quality factors. Increasing N fertility increased yield, total alkaloids, total N, and NO3‐N while lowering burn duration, filling capacity, and value. Nitrogen‐fertilizer rates above 134.4 kg ha−1 N appear to have no benefit. Chemical sucker control increased yields and value with no adverse effect on quality or interaction with the different N‐fertility rates.
Atrazine Effects on Tensile Strength of Centipedegrass Sod1
Authors: Turner D. L. , Dickens R.
Published: July 2010

Centipedegrass [Eremochloa ophiuroides (Munro) Hack.] sod has become more in demand over the past decade, leading producers to attempt to speed production. An increase in the use of the herbicide atrazine [6‐chloro‐N‐ethyl‐N'‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] for weed control has been one result. Numerous sod producers in the Southeast have experienced difficulty harvesting sod due to inadequate tensile strength. The object of this study was to determine the effects of atrazine on the tensile strength of centipedegrass sod. The experiment was conducted during 1982, 1983, and 1984 at Auburn, AL, on a Dothan sandy loam (Plinthic Paleudult) and during 1982 and 1983 at Tuskegee, AL, on a Gilead sandy loam (Aquic Hapludult) and a Leaf silt loam (Typic Albaquult), respectively. Atrazine was applied to centipedegrass at 0.6, 1.1, and 2.2 kg ha−1 rates at 2‐ and 4‐week intervals during the growing season. Visual injury ratings were taken in July, September, and May, and sod tensile strength measurements were taken in September and May following applications. Visual observations indicated that injury was increased as atrazine rates and application frequencies increased. Less Injury occurred in 1983 at both locations. Visual injury ratings were not consistent with sod tensile strength measurements. Measurements of sod tensile strength revealed that increasing rates of atrazine reduced the tensile strength in a linear fashion. Injury was greater with the 2‐week application interval. Reduction of tensile strength was more evident with sod harvested in September than in May at both locations. Sod tensile strength of untreated centipedegrass was higher during September than during the following May and at the Auburn location.
Nitrogen Transfer from Siratro to Kleingrass: Competition for Mineral Nitrogen and Isotopic Fractionation1
Authors: Ismaili M. , Weaver R. W.
Published: July 2010

Availability of combined N limits productivity of Kleingrass (Panicum coloratum L.) when grown with siratro (Macropitilium atropurpureum D.C. Urb.). An experiment was undertaken in a glasshouse to measure the quantity of N transferred from siratro to Kleingrass and the competitive relationship between siratro and Kleingrass for mineral N. Plants were grown for 187 days in pure stand and in mixture and fertilized with two rates of 15N‐labelled (NH4)2SO4 provided in split applications. The only sources of N to the plants was from the labelled fertilizer and biologically fixed N by siratro. Kleingrass obtained approximately 60% of the N recovered when grown with siratro at either rate of N fertilization. Siratro transferred biologically fixed N to Kleingrass, which accounted for 14 and 5% of the total N in the Kleingrass for the low and high rates of N fertilization, respectively. Isotopic fractionation of N occurred between shoots and roots of Kleingrass and was not a result of fractionation during N uptake. Caution needs to be exercised in assuming isotopic fractionation does not influence results of experiments using isotope dilution to measure N fixation.
Greenness‐Leaf Area Index Relationships of Seven Row Crops1
Authors: Redelfs M. S. , Stone L. R. , Kanemasu E. T. , Kirkham M. B.
Published: July 2010

Remote sensing technology has potential for nondestructive estimation of green leaf area index (LAI). We applied the greenness transformation to ground‐based reflectance data taken over seven crops [sweet and field corn, Zea mays L.; grain sorghum, Sorghum bicolor (L.) Moench; pearl millet, Pennisetum americanum (L.) Leeke; pinto bean, Phaseolus vulgaris L.; soybean, Glycine max (L.) Merr.; and sunflower, Helianthus annuus L.] grown on Eudora silt loam soil (coarse‐silty, mixed, mesic Fluventic Hapludoll) to determine reflectance‐LAI relationships, and to see if those relationships were crop specific or could be applied more generally to several crops. Spectral reflectance data were collected with a radiometer equipped with four wavelength bands that simulated the Landsat multispectral scanner bands. The coefficients for brightness and greenness were calculated by using reflectance data and published calculation procedures. Greenness coefficients for the reflectance data for all crops were very similar. Models were developed that related greenness (calculated by using the individual crop greenness coefficients or the coefficients developed from combined data of all crops) and field estimates of green LAI. All models were significant (P<0.0001) and linear, with the regression coefficients equal to what we termed the crop factor. Intercepts were not significantly different from zero (P>0.05). The combined greenness coefficients were not significantly different than individual crop coefficients in relating greenness to field‐estimated LAI. The crops were grouped into grass or broadleaf to determine general crop factors. It made no significant difference whether the individual crop factor or the combined crop factor (for grass, 0.197; for broadleaf, 0.117) was used in developing the greenness‐estimated LAI that was related to field‐estimated LAI. This study illustrated that the greenness coefficients developed for each of seven row crops were very similar and the regression coefficients from the linear relationship between LAI and reflectance greenness were very similar within the grass crops and within the broadleaf crops.
Yield and Biochemical Response of Sugarbeet to Benomyl1
Authors: Smith G. A. , Martin S. S.
Published: July 2010

Two field studies were conducted to determine the effects of the systemic fungicide benomyl [methyl 1‐(butylcarbamoyl)‐2‐benzimidazolecarbamate] applied at protectant levels to the foliage of sugarbeet (Beta vulgaris L.), on yield components, recoverable sucrose, and six root extract chemical constituents. In the initial study (1980 and 1981), six benomyl applications (271 g a.i. ha−1, at 2‐week intervals beginning in late June) to disease‐free sugarbeets significantly increased yield components and decreased amino N, total N, and betaine. The objective of the second study (1982–1984) was to determine the effect of timing and number of benomyl applications during the growing season. In each year, five benomyl treatment regimes, ranging from single applications to six sequential applications, were evaluated for their effects. All non‐sucrose chemical component means across cultivars decreased as a result of benomyl treatment. These reductions were consistent and statistically significant for total N, amino N, and betaine. Means for sucrose, purity, and root weight increased in response to benomyl in 1980 and 1981 although not significantly so for sucrose. There was a significant year‐effect on changes in yield components and lack of consistency for any given treatment on extract chemical composition. Thus, these data did not point to a specific physiological basis for the observed effects.
Growth and Yield Response of Solid‐Seeded Soybean to Early Season Stand Reduction1
Authors: Torri K. , Vasilas B. L. , Carmer S. G. , Smyth C. A.
Published: July 2010

Soybean [Glycine max (L.) Merr.] stands can be reduced by hail storms, soil crusting, poor seed vigor, and other factors. Little information is available on the response of solid‐seeded (drilled) soybean to stand reduction. Four experiments were conducted at the University of Illinois on a Drummer silty clay loam (Typic Haplaquoll) in 1984 and on a Flanagan silt loam (Aquic Argiudoll) in 1985 to evaluate the growth, yield, and yield component response of solidseeded soybean to early season stand reduction. Four levels of stand reduction (0, 25, 50, 75%) were imposed at two growth stages (V3, V6) on ‘Hobbit’ (determinate, semidwarf, Maturity Group III) and ‘Pella’ (indeterminate, normal height, Maturity Group III) soybean, planted on 16 May 1984 and 13 May 1985 in 0.175‐m‐wide rows with a seeding rate of 560 000 seed ha−1. With a few exceptions, the growth stage at which stand reduction treatments were imposed did not affect the parameters measured. Seed yields of Pella in 1985 were constant over a population range of 130 000 to 468 000 plants ha−1. Averaged across the two growth stages, 75% stand reduction, which reduced the population to an average of 118 000 remaining plants ha−1, reduced yields of Hobbit in 1984 and 1985, and Pella in 1984 by 11, 14, and 15%, respectively. Across experiments, a population of 308 600 plants ha−1 was found to be adequate for maximum yields. Yield reductions in Hobbit were associated with decreased seed number; yield reductions in Pella were associated with decreased seed size. Seventy‐five percent stand reduction delayed canopy closure and increased branch number per plant in all cases, and increased internode number per plant in Pella.
Soybean Specificity for Bradyrhizobium japonicum Strain 1101
Authors: Howle P. K. W. , Shipe E. R. , Skipper H. D.
Published: July 2010

The specificity of six Maturity Group VII soybean [Glycine max (L.) Merr.] cultivars to inoculation with Bradyrhizobium japonicum Strain USDA 3I1b110 was measured relative to indigenous B. japonicum populations in 1981 and 1982 in two environments in South Carolina. The Clemson experiment was on a Chewacla soil (fine‐loamy, acid, thermic Aquic Fluventic Dystrochepts) in 1981, and on a Toccoa soil (coarse‐loamy, mixed, nonacid, thermic Typic Udifluvents) in 1982. The Florence experiments were on a Norfolk soil (fine‐loamy, siliceous, thermic Typic Paleudults). Top dry weight and plant N content, and the number and dry weight of nodules per plant were determined at the R5 growth stages. Seed yield and N content were also measured. No differences were detected (≤0.05) due to inoculation for any variable studied. Genotypic differences occurred in harvest yield rankings, with three of the four tests having similar cultivar rankings. Nodule occupancy was determined by serological assay against 15 antisera. Serogroup 110 was not recovered from the Clemson sites and ≤ 8% from the Florence site. Serogroup 31 was the predominant, indigenous strain identified at both locations and occupied 9 to 34% of the nodules. Nodule occupancy by a less efficient serogroup, 31, is a limiting factor to soybean production. No specificity was detected between Strain 110 and six soybean cultivars.
Fermentation Inhibition of Forage and Sweet Sorghum Silages Treated with Acrylic or Maleic Acid1
Authors: Hill N. S. , Posler G. L. , Bolsen K. K.
Published: July 2010

One source of biomass for conversion to liquid fuel is sweet sorghum [Sorghum bicolor (L.) Moench]. Its potential use as an alcohol feedstock is limited by a harvesting season too short to supply batch fermenters with a constant source of substrate. One solution is to conserve sugars by ensiling the crop with fermentation inhibitors. ‘Rio’, ‘Dale’ and DeKalb ‘FS25A’ sorghums were harvested at physiological maturity and treated with 2.5 or 5.0 g of acrylic or maleic acid per kilogram of herbage. Treated herbage was analyzed for glucose, fructose, sucrose, dry matter, and protein concentration. After 130 days fermentation, silages were analyzed for these factors plus ammonia, lactic acid, and volatile fatty acids. Dale and FS25A herbage had proportionately higher sugar monomers and lower total sugar conservation than Rio. Sugar recovery increased from less than 100 g kg−1 to 987 g kg−1 with acrylic acid application but was unaffected by maleic acid. Both acid treatments decreased lactic and acetic acid production, while silages treated with acrylic acid had higher ammonia and propionic and valeric acid production, and pH. Ammonia production decreased in silages receiving maleic acid. These data indicate that sweet sorghum treated with acrylic acid can be stored as silage without appreciable sugar loss.
Long‐Term Yield Data Used to Define Production Areas for Hard Red Spring Wheat1
Authors: Campbell L. G.
Published: July 2010

An effective cultivar development or testing program depends on the identification of nursery locations and testing sites that are representative of those encountered in commercial production. Defining unique production areas within a region often is complicated by the inability of the researcher to accurately determine the factors influencing crop response. Long‐term (1919–1983) county yield data for spring wheat (Triticum aestivum L.) were used as a basis for defining and characterizing production areas within North Dakota. Cluster analysis indicated that the state reasonably could be divided into five areas. These areas were characterized by differences in mean yield, standard deviation, range of yields, and stability of yield as measured by regression of county yield upon the state mean yield. A regression equation relating yield to distance north and east of the southwest corner of the state was used to construct yield isolines. The areas delineated by the cluster analysis and the pattern of the isolines were consistent with general physiographic areas of the state and climatic gradations. It was demonstrated that long‐term county yield data can provide a basis for defining production areas.
Soil Water Deficit Effect on Yield, Leaf Area, and Net Assimilation Rate of Three Forage Grasses: Crested Wheatgrass, Smooth Bromegrass, and Altai Wildrye1
Authors: Bittman S. , Simpson G. M.
Published: July 2010

Annual forage yield in the northern Great Plains depends primarily on quantity and temporal distribution of precipitation. This study was conducted to examine the effect of water deficit on yield, leaf area, and net assimilation rate (NAR) of three forage grasses under field conditions. The grasses, smooth bromegrass (Bromus inermis Leyss.) (Br), Altai wildrye [Leymus angustus (Trin.) Pilger] (AWr), and crested wheatgrass [Agropyron cristatum (L.) Beauv. spp. pectinatum (Bieb.) Tzvel.] (CWg), were chosen because of their contrasting morphologies. The grasses were grown on deep black soil (Melfort silty clay, Typic Cryoboroll) under two moisture regimes: DRY plots were covered by rain‐out shelters starting at the end of May, and IRR plots were watered when soil water potential averaged −0.07 MPa. Crested wheatgrass expanded leaf area more rapidly in spring than Br and AWr, and responded to increasing soil water deficits by sharply reducing its leaf area through senescence of older leaves. Altai wildrye developed its leaf area slowly, probably because more dry matter was required to produce a unit of leaf area. It responded to soil water deficit by reducing rate of leaf expansion. Smooth bromegrass developed its leaf area rapidly although somewhat later than CWg. The effect of soil water deficit on leaf expansion was less in Br than AWr, and its effect on reduction of leaf area through leaf senescence was less in Br than CWg. In late May, AWr yielded less than CWg but more than Br. At the end of June, yield of CWg was greater than both Br and AWr in 1983, and greater than AWr but similar to Br in 1984. Altai wildrye recovered most rapidly after clipping among the species in both years but yielded more regrowth only in 1984. No interaction was found between moisture regime and species for either leaf area or yield on any of the sampling dates, probably because soil water deficits developed gradually under the conditions of this experiment, thus minimizing the effects of the different growth patterns. Soil water deficit affected leaf area proportionately more than NAR in AWr and CWg but not in Br. The findings suggest that the relative effect of drought on these two yield components depends on species and environment.
Herbicide Tolerance of White Lupin1
Authors: Wiedenhoeft M. Hagemann , Ciha A. J.
Published: July 2010

Lupin (Lupinus albus L.), a high protein grain legume, has the potential of being grown in the Pacific Northwest as an alternative crop for pea (Pisum sativa L.) and lentil (Lens culinaris L.). Greenhouse studies were conducted to determine the tolerance of the white lupin cultivar Astra to preplant incorporated (PPI), preemergence (PRE), and postemergence (POE) applications of herbicides commercially available for other grain legumes. All herbicide applications were made at two rates; the rate labelled for pea, lentil, or soybean [Glycine max (L.) Merr.], and three times the labelled rate. Six weeks after application, plant height, shoot dry weight, and visual injury were determined for all plants. Triallate [S‐(2,3,3‐trichloro‐2‐propenyl)bis(1‐methylethyl)carbamothioate] at 1.4 and 4.2 kg a.i. ha−1, trifluralin [2,6‐dinitro‐N,N‐dipropyl‐4‐(trifluoromethyl)benzenamine] at 0.8 kg a.i. ha−1 applied PPI, fluazifop [(±)‐2‐(4‐{[5‐(trifluoromethyl)‐2‐pyridinyl]oxy}phenoxy)propanoic acid} at 0.3 kg a.i. ha−1, and diclofop {(±)‐2‐[4‐dichlorophenoxy)phenoxy] propanoic acid} at 1.1 kg a.i. ha−1 applied POE did not reduce shoot dry weight. Atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐ triazine‐2,4‐diamine] and EPTC (S‐ethyl dipropylcarbamothioate) applied PPI, metribuzin [4‐amino‐6‐(1,1‐dimethylethyl)‐3‐(methylthio)‐ 1,2,4‐triazin‐5(4H‐one] applied PRE, and the herbicides atrazine, bentazon [3‐(1‐methylethyl)‐(1H)‐2,1,3‐benzothiadiazin‐4(3H)‐ one2,2‐dioxide], 2,4‐DB ester [4‐(2,4‐dichlorophenoxy)butanoic acid], dinoseb [2‐(1‐methylpropyl)‐4,6‐dinitrophenol], fluorochloridone [3‐chloro‐4‐(chloromethyl)‐1[ 3‐(trifluoromethyl)phenyl]‐2‐pyrrolidinone], MCPA Na salt [(4‐chloro‐2‐methylphenoxy)acetic acid], and metribuzin applied POE severely injured the lupins. Greater visual injury occurred when the POE herbicides were applied at the one to two‐leaf stage than at the five‐ to six‐leaf stage.