bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Tillage and Windbreak Effects on Millet and Cowpea: I. Wind Speed, Evaporation, and Wind Erosion
Authors: Banzhaf J. , Leihner D. E. , Buerkert A. , Serafini P. G. 
Published: July 2010

AbstractDeforestation, overgrazing, and declining soil regeneration periods have resulted in increased wind erosion problems in dry areas of the West African Sahel, but little is known about the bio‐physical factors involved. This research was conducted to determine the effects of ridging and four different windbreak spacings on wind erosion, potential evaporation, and soil water reserves. A field trial was conducted from 1985 to 1987 on 12 ha of a Psammentic Paleustalf in Southern Niger. Millet, Pennisetum glaucum (L.), and cowpea, Vigna unguiculata (L.) Walp., were seeded in strips on flat and ridged soil. Windbreaks of savannah vegetation were spaced at 6, 20, 40, and 90 m. The effects of ridging on wind speed, evaporation, and wind erosion were small and mostly non‐significant. However, average wind speed at 0.3 m above ground in the center of cowpea and millet strips was significantly reduced from 2.8 to 2.1 m s—1 as windbreak distances narrowed from 90 to 6 m. As a consequence, potential evaporation declined by 15% and the amount of wind blown soil particles by 50% in ridged and by 70% in flat treatments. Despite reduced potential evaporation, average subsoil water reserves were 14 mm smaller in the 6‐ than in the 20‐m windbreak spacing indicating excessive water extraction by the windbreak vegetation. Thus, establishing windbreaks with natural savannah vegetation may require a careful consideration of the agronomic benefits and costs to competing crops.
Changes in Soluble Carbohydrate Composition of Barley, Wheat, and Rye during Winter
Authors: Olien C. R. , Clark J. L. 
Published: July 2010

AbstractSignificant increases in the production of winter cereals could be realized with improved hardiness. The objective of this research was to determine if overwintering cereals modify water soluble carbohydrate composition in response to naturally occurring winter freeze stress. Fields of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and rye (Secale cereals L.) were monitored throughout the winter between 1986 to 1990 for snow‐pattern development, temperature, and snowfall. Plant crowns were analyzed for freeze injury (form and intensity) and water soluble carbohydrate composition (fructan, sucrose, glucose, and fructose). Growth chamber plants were frozen and analyzed to confirm the interpretation of field plant data. In 1986, there was less fructan and more soluble sugars in the exposed than in the snow‐covered wheat plants (but no complete depletion of fructan), and no crown injury from equilibrium freezing. In 1987–1988, little injury or fructan hydrolysis occurred in barley, wheat, or rye; the plants were snow covered during cold periods. In 1989–1990, fructan hydrolysis to sugar in exposed barley, wheat, and rye plants paralleled that in the exposed wheat plants of 1986–1987. The fructan content of exposed barley plants was nearly depleted during the coldest weather. Exposed plants had typical equilibrium freeze injury. Growth chamber plants responded similarly to the exposed field plants. Plants exposed to freeze stress converted fructan to sugars which probably alleviated adhesive freeze stress. The energy of hydrolysis may be useful for placing sugar into sites within the tissue where its cryoprotective activity is most effective.
Ryegrass Companion Crops for Alfalfa Establishment: II. Forage Quality in the Seeding Year
Authors: Sulc R. M. , Albrecht K. A. , Casler M. D. 
Published: July 2010

AbstractRyegrass (Lolium spp.) use in the northcentral USA has been limited by its lack of winterhardiness. But potential exists for its use in this region as a companion crop for alfalfa (Medicago sativa L.) establishment. This study was conducted to determine nutritional value of forage from ryegrass‐alfalfa mixtures in the seeding year. Five ryegrass cultivars, representing four species, were sown at 215, 430, and 645 seeds per square meter with alfalfa at two locations in Wisconsin in April of 1988, 1989, and 1990. Alfalfa was also established alone and with oat (Avena sativa L. ‘Ensiler’). Forage from mixtures of annual ryrgrass (L. multiflorum Lam.) was usually lower in crude protein (CP) concentration and higher in fiber concentration (neutral‐and acid‐detergent fiber) than forage from intermediate ryrgrass (L. hybridum Hausskn.) or perennial ryegrass (L. perenne L. and Festulolium braunii K. A.) mixtures. A threefold increase in ryegrass seeding rate usually reduced nutritional value of the forage. At the first harvest, forage from all ryegrass‐alfalfa mixtures was higher in CP concentration and lower in fiber concentration than the oat‐alfalfa forage. At subsequent harvests, the nutritional value of ryegrass‐alfalfa forage was inferior to that of forage regrowth in the oat companion crop seeding, except in dry environments when alfalfa predominated in the ryegrass‐alfalfa mixtures. We conclude that ryegrass‐alfalfa mixtures in the northcentral USA can provide forage with higher nutritional value than oat companion crop seedings at the first harvest in the establishment year, but not at subsequent harvests, especially when adequate rainfall promotes vigorous ryegrass growth.
Spring‐Clipping Response in Snake River and Thickspike Wheatgrasses
Authors: Jones T. A. , Nielson D. C. 
Published: July 2010

AbstractGrazing at the boot stage can severely damage stands of bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) A. Löve]. Snake River wheatgrass [proposed name Etymus lanceolatus ssp. wawawaiensis (Scribner & Gould) J.R. Carlson & D.R. Dewey] has recently been recognized as a taxon distinct from bluebunch wheatgrass, based on cytological data, and placed in the same species as thickspike wheatgrass [Elymus lanceolatus ssp.lanceolatus (Scribner & J.G. Smith) Gould]. Grazing tolerance of Snake River wheatgrass is unknown. This study was conducted to evaluate the effect of clipping at the boot stage on vigor of ‘Secar’ Snake River wheatgrass, ‘Elbee’ and T‐21076 thickspike wheatgrass, and hybrid populations D30 (50% Snake River wheatgrass/50% thickspike wheatgrass) and D38 (75% Snake River wheatgrass/25% thickspike wheatgrass). Plots were established at North Logan, UT (mollisol) and near Stone, ID (aridisol) in 1987, clipping treatments (clipped or unclipped at the boot stage) were applied in 1988 and 1989, and treatments were compared in 1990. Regardless of spring‐clipping treatment, all plants were clipped once in the summer at both locations and again in the fall at North Logan both in 1988 and 1989. Spring clipping reduced Secar dry weight 21%, spike number 27%, and plant basal area (above‐ground area occupied by tillers) 17% at North Logan, while the other populations were unaffected. Spring clipping reducedry weight 26 and 31%, spike number 37 and 36%, and plant basal area 24 and 33%, of Secar and D38, respectively, near Stone, while the other populations were unaffected. Spring clipping was more detrimental at the Stone aridisol than the North Logan mollisol site. Currently available germplasm of the rhizomatous thickspike wheatgrass appears to be more tolerant of spring clipping than that of the caespitose Snake River wheatgrass. It should be possible to make substantial genetic progress for spring‐clipping tolerance in hybrid populations.
Shading and Crop‐Cover Effects on Meadowfoam Oil Yield
Authors: Norberg O. S. , Fiez T. E. , Jolliff G. D. , Seddigh M. , Crane J. M. 
Published: July 2010

AbstractMeadowfoam (Limnanthes alba Hartw. ex Benth. subsp. alba cv. Mermaid) seed yield and oil yield vary among years. Consistent high oil yield is needed to encourage profitable commercialization. Field experiments were conducted at Oregon State University in 1987–1988 and 1988–1989 on an Amity silt loam (fine‐silty, mixed, mesic Argiaquic Xeric Argialboll) to test the hypothesis that light and temperature effects before the beginning of rapid elongation of stems influence oil yield through alteration of phytomass (total aboveground dry matter) development. Shade‐cloth and a transparent floating crop cover were used to alter light and temperature, compared to the control. Cover early, cover early plus late, and shade treatments were applied on 22 Jan. 1988 and 24 Jan. 1989. Shade and cover early were removed 29 Mar. 1988 and 28 Mar. 1989; and cover early plus late was removed 12 April 1988 and 11 April 1989. At 2 wk after the beginning of rapid elongation of stems, shaded plants had 24% less phytomass and 28% fewer stems than the control. Shade increased open flowers 27%, seeds per square meter 30%, seed yield 35%, seed oil content 8%, and oil yield 47%. Cover early increased open flowers 23%, seeds per square meter 34%, seed yield 21%, seed oil content 9%, and oil yield 33%. Effects of cover early plus late treatment on crop growth and yield were inconsistent between years. Seed yield improvement by all treatments was associated with fewer primary stems per plant, more flowers that opened, and more seeds per square meter. Genetic manipulation and cultural practices which reduce the number of primary stems per plant and increase the number of flowers opened may lead to increases in oil yield.
Subterranean Clover Enhances Production of ‘Coastal’ Bermudagrass in the Revegetation of Lignite Mine Spoil
Authors: Harris Pamela A. , Zuberer David A. 
Published: July 2010

AbstractLignite mine spoils in Texas are commonly revegetated with ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.]. Legumes hare been overseeded in bermudagrass in reclamation programs in Texas, but information regarding establishment and persistence in mine spoil is limited. Therefore, we conducted a field study to investigate the effects of fertilization and inoculation with Rhizobium spp. on subterranean clover (Trifolium subterraneum L.; subclover) establishment and production in mine spoil and to assess the effect of subclover on a subsequent crop of Coastal bermudagrass. Subclover seed was broadcast into a 6‐mo‐old bermudagrass sod in October 1986. Individual plots were fertilized with 57‐25‐47 kg ha−1 (N‐P‐K), 0‐25‐47 kg ha−1, or left unfertilized at the beginning of each clover season (Sept.–Oct.); however, all plots were fertilized with 57‐25‐47 kg ha−1 at the start of each grass season (April‐May) to ensure grass growth. Although low numbers (0–l02 g‐1) of native rhizobia were present in plots, inoculation with a commercial, multi‐strain inoculant increased subclover forage production (100%) and total N and P yields of subclover early in the first season. Yields from inoculated and uninoculated plots were generally comparable later in the first season and in the second year. The overseeding of subclover into the bermudagrass sod increased grass production and total N and P yields later in the first year and in the second season. However, inoculation of subclover had little effect on subsequent grass production. We also demonstrated the apparent positive benefit of P fertilization on subclover and bermudagrass production. Clover forage production, as well as N and P yields, were enhanced with P fertilization. In addition, P fertilization was necessary to achieve the greatest benefit of clover enhancement of bermudagrass production. The effect of subclover on grass production was apparent by the end of the first grass season, and it became even more evident in the second year. The results showed that subclover was established and maintained for at least two seasons in a bermudagrass sod on reclaimed lignite spoil, and that the clover benefited the subsequent grass crop when fertilized with P and K, apparently by providing extra “fixed” N for grass production.
Bahiagrass Canopy Size, Soil Water, and Establishment of Aeschynomene
Authors: Kalmbacher R. S. , Martin F. G. , Hammond L. C. , Boote K. J. , Mislevy P. 
Published: July 2010

AbstractAeschynomene americana L. is a tropical pasture legume, and in Florida, where it is usually grown with bahiagrass (Paspalum notatum Flügge), there are about 5000 ha. Limited soil water is a primary reason for stand failure of this annual. Soil water in three bahiagrass canopy sizes: small (2.2 leaf area index [LAI]), medium (4.5 LAI) and large (7.7 LAI) was measured at seeding and related to aeschynomene establishment. All canopies were clipped to a 50‐mm height when aeschynomene seedlings emerged. Soil was Eau Gallie fine sand (sandy, siliceous, hyperthermic Haplaquods). Aeschynomene was drilled into sod on 17 dates between May and July in 1981 to 1985, and seedling density was determined at emergence and periodically for 21 d. Six of the 17 seedings were failures because of drought (one because of flooding), and when failure occurred, it was in all three canopy sizes. Water potential at 75‐ and 150‐mm soil depths was analyzed from 209 dates, and canopy size affected soil water potential on 41 dates. Gravimetric soil‐water was analyzed on 42 dates, and canopy size affected (P ≤ 0.05) gravimetric soil‐water on five dates. Evapotranspiration (ET) rate was measured twice and was not different among canopy sizes on 26 June 1984 (avg. 94 mg m−2 s−1). Differences (P ≤ 0.03) in ET rate were found on 16 May 1986 when the large canopy (128 mg m−2 s−1) had greater ET rate than the small canopy (100 mg m−2 s−1), with the medium canopy (117 mg m−2 s−1) intermediate. Bahiagrass canopy size before aeschynomene emergence had little effect on the amount of soil water and resulting success or failure of aeschynomene. Only rain and soil water potential were useful for predicting aeschynomene stand success. Together, rain 0 to 8 d before seeding [descriminant value (DV) ≤ 22 mm] and soil water potential at seeding (DV ≤ −15 kPa) correctly predicted 13 out of 17 seedings.
Plant Yields and Fodder Quality Related Characteristics of Millet‐Stylo Intercropping Systems in the Sahel
Authors: Kouamé C. N. , Powell J. M. , Renard C. A. , Quesenberry K. H. 
Published: July 2010

AbstractThe integration of forage legumes into the low‐input, cereal‐based farming system of the Sahel may be the key to sustaining soil, crop, and livestock production. The objectives of this study were to evaluate the effects of intercropping the forage legumes Stylosanthes fruticosa (Retz.) Alston or S. hamata (L.) Taub. with millet [Pennisetum glaucum (L.) R. Br.] on grain yield, fodder yield, and crude protein (CP) yield and concentration. Four field trials were conducted on a Psammentic Paleustalf (siliceous, isohyperthermic) soil from 1988 to 1990 at Sadoré, Niger. Each Stylosanthes species was grown in alternate single and triple row patterns with millet for 1 and 2 yr, with stylo regrowing from stubble during the second year. Control treatments were sole crops of millet and stylo. Intercropping either Stylosanthes species with millet for 1 yr in alternate single rows did not affect millet grain yield, because of low stylo competition. Total dry matter (DM) harvested of intercrop was similar to that of sole millet, while CP concentration of total DM increased moderately from 43 g kg−1 in sole millet crop to 75 g kg−1 in intercrop. During the second year of association, stylo was very competitive, depressing intercropped millet grain by an average of 67% in 1989 and 48% in 1990 compared with sole millet grain yield. Total DM and CP yields, and CP concentration of the harvested fodder were, respectively, 1.4, 3.0, and 2.3 times greater in intercrop than sole millet. Millet‐stylo intercrops, with each species planted at half its sole crop density, appear to have an advantage in fodder yield and CP over sole millet cropping but not in total grain yield.
Nitrogen Availability from Surface‐Applied and Soil‐Incorporated Crop Residues
Authors: Smith S. J. , Sharpley A. N. 
Published: July 2010

AbstractManagement systems which maintain crop residues on the soil surface have prompted a need for more detailed information regarding crop residue N availability. Such information is needed from both agronomic and environmental standpoints. Our study examined the placement effects of 15N tagged alfalfa (Medicago sativa L.), sorghum [Sorghum bicolor (L.) Moench], and wheat (Triticum aestivum L.) residues on crop residue N availability in association with eight Oklahoma surface soils representing five soil orders. The experiment was conducted under aerobic laboratory conditions, and involved 0.25‐mm crop residue materials and 2‐mm soil particles. Crop residue N availability was determined on the basis of N mineralized during short‐term (14 d) and long‐term (168 d) incubation. Mean amounts of crop residue N mineralized ranged from <18 kg N ha−1 for sorghum and wheat (<28% of residue N) to 55 kg N ha−1 for alfalfa (35% of residue N). Surface placement of crop residue reduced residue N availability compared to soil incorporation, but the differences were only equivalent to 1 to 7 kg N ha−1. Relative to residue type, the influence of soil type on crop residue N mineralization was secondary. Overall, differences in crop residue N availability associated with residue placement should have minor agronomic and environmental impact.
Broadcast Nitrogen Sources for No‐Till Continuous Corn and Corn Following Soybean
Authors: Stecker J. A. , Buchholz D. D. , Hanson R. G. , Wollenhaupt N. C. , McVay K. A. 
Published: July 2010

AbstractStudies evaluating surface broadcast urea‐based N sources in no‐till corn (Zea mays L.) have been primarily conducted with continuous corn. Most corn grown in Missouri follows soybean [Glycine max (L.) Merr.]. Our objective was to evaluate no‐till, continuous corn and corn following soybean response to surface applied ammonium nitrate (AN) and urea‐based N sources. Field studies were conducted at three Missouri sites during 1988–1990. Factorial combinations of rotation (continuous corn and corn‐soybean) N source [AN, urea, urea ammonium nitrate (UAN), and UAN + ammonium thiosulfate (UAN + ATS)], and N rate (67, 135, and 202 kg ha−1) were studied in a split‐block design. Nitrogen rate and source affected grain yields each site‐year. Ammonium nitrate was superior to the urea‐based N sources in 5 of 8 site‐years. Averaged across site‐years, grain yields (Mg ha−1 were 8.22 for AN, 7.57 for urea, 7.09 for UAN + ATS, and 6.99 for UAN. Apparent fertilizer N losses were estimated at 11% for urea, 18% for UAN and 17% for UAN + ATS. Ammonium thiosulfate did not improve the performance of UAN. Grain yield responses to applied N were greater with continuous corn than corn following soybean. Continuous corn also resulted in larger yield differences between N sources. In continuous corn, AN resulted in greater grain yield than urea by 0.81 Mg ha−1, than UAN by 1.35 and Mg ha−1, and than UAN + ATS by 1.32 Mg ha−1. For corn following soybean, the yield advantage for AN was 0.42 Mg ha−1 greater than urea, 0.98 than UAN, and 0.82 than UAN + ATS. Therefore, reduced fertilizer efficiency of surface applied urea‐based N sources appears to be a problem in both continuous no‐till corn and no‐till corn following soybean.
Traversing Sensor Platform for Environmental Measurements
Authors: Ham Jay M. , Caldwell F. W. 
Published: July 2010

AbstractUnder conditions of high spatial variability, environmental sensors can be transported across or through the region of interest to obtain representative samples of the measured parameter. A traversing platform was designed to carry heavy sensors and instruments along a horizontal path under field conditions. The system was composed of a 0.17‐ by 0.13‐m rolling platform atop a 2.2‐m long aluminum channel. A motorized cable‐chain drive was used to move the platform at a speed of 0.035 m s−1. The system was powered with 12‐V DC deepcycle batteries and consumed ≈6 W of power when the sensor platform was in transit. On‐board circuits can be used in conjunction with a programmable datalogger to sense the platform's location or stop the platform at user‐specified locations along the traversing path. The mechanism was capable of transporting a 5‐kg sensor package at inclination angles up to 45°. The system operated without failure for a 6‐wk period under field conditions.
Dry Matter Production, Yield, and Allocation of Carbon‐14 Assimilates by Wheat as Affected by Nitrogen Source and Salinity
Authors: Botella M. A. , Cerdá A. C. , Lips S. H. 
Published: July 2010

AbstractWheat (Triticum aestivum L.) growth is affected by both salinity and the type of N fed to the plants. The objective of this research was to determine the effect of salinity applied at different stages of the life cycle of wheat plants supplied with either NH4 or NO3 on growth, yield, and translocation of photosynthates. Plants were grown in sand culture irrigated with nutrient solution until maturity. The nutrient solution contained 4 mM N, either as (NH4)2SO4 or Ca(NO3)2. Salinity (60 mM NaCl) was applied to the nutrient solution at 19, 70, and 92 d after sowing. Some of the plants received 14CO2 pulses 100 d after sowing, and 14C distribution in each plant part was determined 24 h later. Dry biomass production and grain yield were reduced when salinity was applied 19 d after sowing (beginning of the vegetative stage), whereas no effect of NaCl was observed when salinity was applied later. Ammonium‐fed plants always produced more tillers and spikes than NO3‐fed plants. Total grain yield was similar with plants growing in either N form. Nitrate‐treated plants produced fewer, but heavier, spikes due to a larger number of grains per spike than NH4‐fed plants. Ammonium‐fed plants showed a preferential allocation of 14C‐assimilates to young developing tillers. Nitrate‐fed plants, under similar conditions, allocated assimilates preferentially to grain. Salinity enhanced translocation of assimilates to the spikes when plants were grown with NO3.
One‐Row Machine for the Harvest of Corn Stover
Authors: Frerichs R. , Brentlinger R. , Shapiro C. A. , Moomaw R. S. 
Published: July 2010

AbstractMany corn (Zea mays L.) experiments require total dry matter determination in addition to grain yield. Mechanized small‐plot grain harvest is a common practice, but determination of total dry matter is usually accomplished by hand harvesting. Hand harvesting is time consuming and labor intensive. Our objective was to construct a mechanized stover sampling system that would reduce the labor requirements for collecting dry matter data. A machine was assembled that cuts, chops, and delivers corn stover to a bag without hand cutting and carrying. A New Holland 707 forage harvester was modified and rear‐mounted on a Model 1910 Ford tractor to harvest a single row with a minimum width of 0.76 m. Chopped corn stover is blown through a tube over the top of the tractor to a platform on the front of the tractor where the material is collected and weighed. By using this machine, the number of people needed for data collection is reduced from eight to three, and longer rows can be harvested to increase experimental precision.