bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Mobility of Nitrapyrin and Ammonium in a Sandy Soil and Its Effect on Nitrapyrin Efficiency1
Authors: Rudert B. D. , Locascio S. J. 
Published: July 2010

AbstractNitrification inhibition by 2‐chloro‐6‐(trichloromethyl) pyridine (nitrapyrin) has not been consistent on sandy soils. This study was conducted to evaluate movement of nitrapyrin and N in a fine sand as influenced by water rate and leaching period. In greenhouse studies, nitrapyrin reduced NO8‐N loss from a Kanapaha fine sand (loamy, siliceous, hyperthermic Grossarenic Paleaquult) for only the first 2 weeks of a 5‐week leaching period. In segmented soil columns, nitrapyrin was placed in the soil at a depth from 13 to 15.5 cm. After the soil was leached at water rates of 0, 2.5, and 5 cm/week for 2 and 4 weeks, soil samples were incubated with NH4‐N. Nitrification bioassay of soil above and below nitrapyrin placement showed that nitrapyrin movement was affected more by volatility than by water rate. Movement of NH4‐N from a 13.0 to 15 cm depth was studied in soil columnsthat contained 20 ppm nitrapyrin in the soil. After leaching, NH4‐N and NO3‐N levels were determined at various soil depths. With increases in the rate of water applied and in the leaching period, higher levels of NH4‐N moved to lower depths than nitrapyrin. Movement of NH4‐N away from nitrapyrin may account for the reduced nitrapyrin effectiveness often observed for sandy soils.
Compensatory Growth of Tall Fescue Following Drought1
Authors: Horst G. L. , Nelson C. J. 
Published: July 2010

AbstractEnhancement of growth following short periods of drought stress has been reported in several crop species. If such enhancement follows summer drought‐stress of cool‐season forage grasses, the increased yield from summer irrigation may be offset partially by compensatory growth during fall. Therefore, a 3 year field study was conducted to compare growth responses of tall fescue (Festuca arundinacea Schreb.) grown with and without supplemental irrigation from June through August. Soil was Mexico silt loam (Udollic Ochraqualf) and fertilizer was applied in spring and following each cutting. Plots were harvested six times in 1971, five times in 1972, and four times in 1973. A residual harvest was made on 21 May 1974.During summer the plants that were irrigated had greater forage yields, greater tiller density, greater weight per tiller, higher leaf elongation rates, and higher concentration of water‐soluble carbohydrates (WSC) in leaf tissue as compared with plants that were water‐stressed. Concentration of WSC in stem bases during summer was higher in the water‐stressed plants. Fall growth of plants that had been water‐stressed during summer was greater than that of those that had been irrigated. The enhancement of growth or compensatory effect was associated with higher concentration of WSC in stem bases during late summer, and faster leaf elongation and greater weight per tiller during fall of the previously water‐stressed plants as compared with the summer‐irrigated plants.Compensatory growth following drought stress was still evident the following spring, as indicated by the higher tiller density and greater forage yield. However, the collective compensatory yield of the water‐stressed plants during fall and spring was not great enough to compensate for lower yields during summer. In the third year of the study normal rainfall during summer was higher than duing the first 2 years, and no compensatory growth was noted during fall or the following spring.During the 3‐year study, total yield for the irrigated treatments was 4% larger than that for the water‐stressed treatment. The major response to irrigation was a shift in season of production. Management and breeding objectives should consider the effect of summer irrigation or summer drought on the subsequent performance of cool‐season forage grasses.
Effects of Stage of Maturity on P and S Critical Levels in Subterranean Clover1
Authors: Drlica D. M. , Jackson T. L. 
Published: July 2010

AbstractSubterranean clover is widely used for pastures in western Oregon; however, little information is available on the effects of stage of maturity on P and S critical levels. The response to P and S fertilization, nutrient contents at different sampling dates, and total yields at harvest were evaluated at two locations in Oregon. The soil at one location is mapped as a complex of Oakland and Nonpareil series, which are well‐drained, hillslope soils developed from sedimentary rock. The soil at the second location is a Veneta silt loam, a moderately well‐drained soil formed from old mixed alluvium. On both sites, the P concentration of the mixed grass and clover forage at harvest was higher in plants that had received P fertilization (0.20%) than in plants that had not (0.14%). The concentration of P in the clover component remained relatively stable from mid‐March to mid‐April in both fertilized and unfertilized treatments. The critical level of P for subterranean clover leaflets and petioles collected between mid‐March and mid‐April was approximately 0.25% P. Sulfur fertilization increased yield 45% and more than doubled S concentration of mixed forage. Added S increased S concentrations in the clover at every sampling date. Sulfur concentrations were relatively constant from mid March to mid‐April, and approximately 0.20% S was identified as the critical level for clover samples collected during this time.
Soybean Yield, Leaf Manganese, and Soil Manganese as Affected by Sources and Rates of Manganese and Soil pH1
Authors: Shuman L. M. , Boswell F. C. , Ohki K. , Parker M. B. , Wilson D. O. 
Published: July 2010

AbstractManganese deficiencies in soybeans [Gycine max (L.) Merr.] grown on certain southern Coastal Plain soils of southeastern USA have required that supplemental Mn be applied to obtain maximum yields. The objective of this experiment was to determine sources and rates of Mn needed for optimum yields at two soil pH levels. Soybeans (‘Ransom’) were grown for three years on an Olustee‐Leefield sand (Ultic Haplaquod‐Arenic Plinthaquic Paleudult) with Mn sulfate, manganous oxide, and fritted Mn as sources at 0, 5.6, 11.2, and 22.4 kg/ha rates. Chelated Mn as MnEDTA was used at one‐tenth the rate of the others. Treatments were evaluated by leaf and soil analysis and grain yields.The Mn sulfate, manganous oxide, and fritted Mn were all satisfactory sources and produced relatively high yields. The Mn chelate did not increak yields above the check, except at the highest rate the final year at the higher pH level. Leaf and soil Mn were increased by the sources in the following order: Mn sulfate > Mn oxide > Mn frit > Mn chelate. The rate of Mn from the Mn sulfate and manganous oxide sources that produced optimum yields was 11.2 kg Mn/ha in the final year where soil pH values were 6.9 and Mn was severely deficient on check plots. The frit source may need higher rates to be equal to the other two source since increased yields were observed at the 22.4 kg %/ha rate for frit.
Relay Intercropping Soybeans into Winter Wheat and Spring Oats1
Authors: Chan L. M. , Johnson R. R. , Brown C. M. 
Published: July 2010

AbstractRelay intercropping of soybeans [Glycine max (L.) Merr.] into small grains might allow the two‐crops‐in‐1 year concept to be moved further northward in the U.S. Corn Belt. The small grain crops in such a system might also provide protection against soil erosion on sloping soils currently in conventional soybean production. The objective of this study was to compare monoculture oat (Avena saliva L.), wheat (Triticum aestivum L.), and soybean yields with soybeans relay intercropped into spring oats or winter wheat. Variables considered included small grain and soybean row widths, soybean planting date, and soybean cultivar. Field experiments were conducted on Typic Haploquoll and Typic Argiudoll soils in central Illinois.Interseeding soybeans into small grains did not affect small grain yields. In three of four environments tested, small grain yields in rows 41, 61, and 81‐cm wide averaged yields of 91, 72, and 58%, respectively, of small grains in 21‐cm row widths. In a fourth experiment, where winter wheat rows wider than 21‐cm were created by spring removal of intervening rows, yield reductions were greater than for those planted in wider rows. Monoculture soybeans produced significantly higher yields and taller plants than intercropped soybeans. Reduced growth of intercropped soybeans, especially in narrow rows, was associated with below normal precipitation during both years of experimentation. Soybeans intercropped between 41 and 61‐cm small grain rows yielded between 7 and 93% of monoculture soybeans grown in similar row widths. Soybeans aerially seeded into small grain stands failed to establish a stand, but soybeans conventionally placed in the soil produced acceptable stands. A short determinate soybean cultivar did not appear to withstand early season stress associated with intercropping as well as a tall indeterminate cultivar. In years with normal early season precipitation, successful relay intercropping of soybeans into small grains should be possible.
Influence of Soil Moisture on Soil Solution Cation Concentrations and the Tetany Potential of Wheat Forage1
Authors: Karlen D. L. , Ellis R. , Whitney D. A. , Grunes D. L. 
Published: July 2010

AbstractOutbreaks of grass tetany occur more frequently when cattle are grazing coolseason forages growing on soils that are nearly water saturated. Therefore, we conducted two experiments to study the interaction between soil moisture, cation availability, and cation uptake by winter wheat (Triticum aestivum). Equilibrium soil solution was extracted from three soil types and analyzed for K, Ca, and Mg concentrations. Wheat was then grown in growth chambers on these soils under wet (partially saturated) and dry (below field capacity) moisture regimes to determine if changes found in the cation concentrations in the equilibrium soil solution would be reflected in the cation composition of the wheat. The potential for outbreaks of grass tetany in cattle consuming the forage was estimated from the equivalent ratio K/(Ca + Mg).Soil solution K, Ca, and Mg concentrations increased as the soil water content decreased from approximately 40 to 10 volume percent. Changes in cation concentraions were nonproportional as predicted by the principles of thermodynamics. Potassium concentrations did not change as much as the Ca and Mg concentrations as the soil water content decreased. The K/(Ca + Mg) molar ratio in the extracted soil solution and the equivalent ratio in the wheat forage showed similar changes as soil water content increased in both experiments. These studies showed that, in addition to the effects of increased soil water content on aeration and ion transport mechanisms, changes in cation concentrations in the soil solution may influence the composition of wheat forage and thus increase its potential for inducing grass tetany in grazing cattle.
Precautions on the Use of Anhydrous Ammonia Applicators in Research Plots1
Authors: Moraghan J. T. 
Published: July 2010

AbstractUse of anhydrous NH3 presents certain difficulties not encountered in research involving solid fertilizers. Little information is available concerning the problem of obtaining uniformity of distribution of anhydrous NH3 among injection blades of applicators used in field‐research studies. The influence of orifice size, and flow‐equalizer manifold sleeves on distribution of different NH3 flows from a pressure‐regulator device (John Blue Nitrolator) by a radial manifold was investigated. The work was done with four and seven‐blade applicators with blade spacings of 76 and 30.5 cm, respectively, by collecting released NH3 in water. Variability in distribution was affected by choice of manifold outlet, orifice size, and NH3‐flow rates. Particularly high variability was generally encountered with excessively low, <0.35 kg/ cm2, and excessively high, >3.5 kg/cm2, manifold pressures. Optimal performance for commonly used fertilizer rates was obtained with 0.635 and 0.119‐cm orifices for the four and seven‐blade units, respectively. Uniform spacing of manifold outlets around a radial manifold was efficacious. Some problems commonly encountered when using anhydrous NH3 in experimental work are described and discussed. Researchers using anhydrous NH3 should calibrate applicators for both total quantity of NH3 applied per unit area and uniformity of distribution among injection units.
Portable System for Overhead Irrigation of Small Plots1
Authors: Heatherly Larry G. , Ginn L. H. 
Published: July 2010

AbstractA tractor‐mounted apparatus designed for overhead irrigation of small plots has been constructed with 1.9‐cm diam. thin‐walled electrical conduit. The 3OO‐cm long assembly has ten 1.3‐cm diam. polyvinyl chloride lateral water lines clamped across the 200‐cm width of the framework. Water is supplied to the apparatus by a power‐take‐off pump from a front‐mounted tank on the tractor and is forced through 0.3‐cm diam. holes spaced 15 cm apart on the bottoms of each of the 10 water lines. The front‐mounted tank is graduated in 75‐liter increments and allows water to be applied to a 300 ✕ 200‐cm surface area in multiples of 1.25 cm. An in‐line pressure regulator is used to vary rate of water application. The system, which can be easily dismounted from the tractor, can irrigate 8 to 15 four‐row plots 6 m in length per day, depending on both rate and amount of water applied to individual plots.
Dry Matter Accumulation, Mineral Concentrations, and Nutrient Distribution in Winter Wheat1
Authors: Karlen D. L. , Whitney D. A. 
Published: July 2010

AsbtractFew studies measuring dry matter accumulation and nutrient distribution in hard red winter wheat (Triticum aestivum L.) over the life cycle of the plant have been reported. Therefore, we established an experiment to study the growth and development pattern of ‘Centurk’ wheat in eastern Kansas and to measure changes in the N, P, K, Ca, Mg, Cu, Mn, and Zn concentrations in various plant parts collected throughout the growing season. Total dry matter accumulation was measured by collecting all above ground plant material. Plant samples were fractionated into living leaves, senescing leaves, stems, heads, head parts, grain, and crowns which were dried, ground, wet‐digested, and analyzed. Regression analyses were computed to identify significant trends. Total dry matter accumulation averaged 0.8 metric tons/ha in the fall, and reached a maximum of 13.0 metric tons/ha at physiological maturity. Nitrogen, P, K, Ca, and Cu concentrations in whole plant samples collected during the fall decreased gradually, while Mg and Zn concentrations remained relatively constant. The S and Mn concentrations were extremely variable and showed no significant statistical trends. Nitrogen, P, K, Ca, Cu, Mn, and Zn concentrations decreased in whole plants as they approached physiological maturity. Magnesium concentrations were relatively constant at approximately 0.18% during the spring. Analysis of individual plant fractions showed nutrient changes similar to those found in the whole plant samples. Grain yields from these experiments were similar to those reported for ‘Centurk’ wheat in performance trials. We feel that this information is useful in identifying the pattern of dry matter accumulation and in illustrating changes in nutrient concentrations during the life cycle of hard red winter wheat.
Response of Arrowleaf Clover to Postemergence Herbicides1
Authors: Conrad J. D. , Stritzke J. F. 
Published: July 2010

AbstractPresently there are no herbicides cleared for weed control in arrowleaf clover (Trifolium vesiculosum Savi.) a proven legume for pasture mixtures in the sunbelt. The objective of the study was to determine the selectiveness of 2,4‐DB [4‐(2,4dichlorophenoxy)butyric acid], 2,4‐D [ (24dichlorophenoxy)acetic acid], bromoxynil [3,5dibromo‐4‐hydroxbenzonitrile], MCPA [((4‐chloro‐o‐to1yl)oxy) acetic acid], and dicamba [3,6dichloro‐oanistic acid] for the control of various broadleaf weeds in arrowleaf clover. Field studies were conducted at three locations. Soil classification for these location are: Aquic Paleudolls for location I, Ultic Haplustalfs for location II, and Mollis Albaqualfs for location III. At all three locations the herbicides were applied postemergence to actively growing arrowleaf plants (5 to 15 cm in height) in late March or early April. Visual damage to arrowleaf clover and weeds was estimated after several weeks. Forage production from the various treatments was determined from June samplings and seed production of arrowleaf was determined from July samplings. Of the herbicides evaluated, 2,4DB at 0.56 kg/ha was consistently selective to arrowleaf clover and adequately controlled the broadleaf weeds including seed stalk formation of curly dock (Rumex crispus L.). MCPA at 0.56 kg/ha also controlled the broadleaf weeds but was not consistently selective on arrowleaf clover. The 0.56 kg/ha rate of 2,4‐D also controlled the broadleaf weeds and significantly reduced the forage production of arrowleaf clover. Seed production with the 2,4‐D treatment (0.56 kg/ha rate) was not suppressed as much as forage production and the decrease was only significant at one location. A combination of 2,4D and banvel (0.42 and 0.14 kg/ha respectively) severely damaged the arrowleaf and could be used as a treatment to control arrowleaf clover.
Preemergence Weed Control in Seeded Bermudagrass Stands1
Authors: Fermanian T. W. , Huffine W. W. , Morrison R. D. 
Published: July 2010

AbstractWeed competition is a major cause of poor bermudagrass (Cynodon dactylon (L.) Pers.). stands established from seed. Two separate experiments were undertaken to find a selective preemergence herbicide to minimize weed competition when establishing bermudagrass from seed. In a greenhouse experiment, four preemergence herbicides, each at four rates were applied to three bermudagrass hybrids in two soil types, a Kirkland silt loam (Thermis Uderic Paleustoll), and a Doughtery loamy sand (Thermic Arenic Hoslustalf). After 3 weeks the germinated and growing seedlings were counted. A highway cut slope was the site of the field experiment which consisted of two Preemergence herbicides (terbutryn and metribuzin) applied to four, seeded, bermudagrass strains. Phytotoxic effects of the herbicides on emergence of the bermudagrass and estimates of weed populations were made at 30‐day intervals.Analyses of the greenhouse data indicated metribuzin and terbutryn were relatively non‐toxic to bermudagrass. Oxadiazon and siduron were highly toxic, and eliminated from further consideration. No significant differences were found among rates for any of the herbicides. The bermudagrass cross, Guymon × 10978, had significantly greater germination than the other bermudagrass with optimum germination observed in a Kirkland silt loam soil. Common bermudagrass germinated the quickest and provided the most dense cover of all bermudagrass types used in the field experiment. Greater weed control was obtained with terbutryn than metribuzin. The application of terbutryn at 2.71 kg/ha was the most toxic treatment to the bermudagrass. Terbutryn at 1.36 kg/ha provided good weed control at an acceptable level of toxicity.
Differential Tolerance of Weeping Lovegrass Genotypes to Acid Coal Mine Spoils1
Authors: Foy C. D. , Voigt P. W. , Schwartz J. W. 
Published: July 2010

AbstractPlant genotypes having greater tolerance to mineral stress are needed for use on problem soils. Two examples of such stress are mineral element toxicity (excess Al, Mn, etc.) in strongly acid soils and mine spoils, and Fe‐related chlorosis in certain calcareous soils. Previous studies showed that genotypes of weeping lovegrass (Eragrostis curvula (Schrad.) (Nees) and Lehmann lovegrass (Eragrostis lehmanniana Nees) different widely in their susceptibilities to an Fe‐related chlorosis on calcareous soils. Preliminary observations suggested that certain genotypes also differed in tolerance to acid mine spoils. To test this hypothesis more precisely, 16 genotypes of weeping lovegrass were grown in greenhouse pots of a Pound, Va., coal mine spoil adjusted to pH 3.5 and 4.7 with CaCO3, and in a Beckley, W.Va., spoil having a natural pH of 4.3.Weeping lovegrass genotypes differed significantly in tolerance to the strongly acid mine spoils. For example, in one experiment the relative top yields (pH 3.5/pH 4.7%) varied from 20.8 to 0%. In certain genotypes, tolerance to acid mine spoil coincided with susceptibility to chlorosis on calcareous soils. For example, Morpa, Beltsville Native, NPMC Hill Culture, and common genotypes were among the most tolerant to the acid mine spoil at pH 3.5, but these were among the most susceptible to chlorosis on calcareous soil at pH 7.8. Conversely, the genotypes FQ 22, FQ 150, FQ 7, and FQ 14 died on the spoil at pH 3.5, but were among the most resistant to chlorosis on calcareous soil. No genotype tested was well adapted to both acid mine spoil at pH 3.5 and calcareous soil at pH 7.8. However, most genotypes studied made reasonable growth on mine spoils of pH 4.3 and 4.7. Results indicated that two commercially available cultivars, Morpa and common, were among the most tolerant tested on mine spoil at pH 3.5; hence, additional genetic diversity will be required to improve acid soil tolerance.Plant toxicities produced in the acid mine spoils studied were tentatively attributed to interference by Al and Fe in the uptake and use of Ca and P.
Nitrogen Fertilization of Meadowfoam1
Authors: Johnson J. W. , Devine M. B. , Kleiman R. , White G. A. 
Published: July 2010

AbstractLimnanthes alba Benth. is a potential oil seed crop with unique long chain fatty acids. Information available on the fertility needs for meadowfoam is scarce. Therefore the effects of rate and time of application of N fertilization on seed yield, seed weight, protein, oil, winter survival, flowering date, plant height, and erectness of meadowfoam were studied in the field for 2 years in Maryland. Nitrogen as ammonium nitrate was applied on plots of two plant introductions at the rates of 0, 45, and 90 kg/ha in the fall (planting) or early spring. In 1976, N was also applied in both fall and springThe seed yield of meadowfoam was decreased as much as 24% with the addition of 90 kg N/ha. Seed yield was linearly related to N application. For each 10 kg/ha applied, the seed yield decreased approximately 3%. The time of N application had no significant effect on seed yield. Seed weight was not affected by rate or time of N application. The protein content of the seed was directly related to the rate of N applied with an increase of 1 and 30%, for each 10 kg N/ha in PI 374790 and 374800, respectively. The combined fall and spring application of N resulted in a 5 and 10% increase in the protein content over the individual fall and spring application, respectively. The addition of 90 kg N/ha resulted in a 12% average reduction in the oil content of the seeds. The time of N application did not affect the oil content for either year. The correlation between seed weight and oil content was positive, r = 0.92 (at the 0.01 level). Increasing N fertilization resulted in significant decrease in seed yield and oil content but an increase in protein content.