bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Reed Canarygrass and Tall Fescue as Spring‐Summer and Fall‐Saved Pasture1
Authors: Bryan W. B. , Wedin W. F. , Vetter R. L. 
Published: July 2010

AbstractDry matter (DM) digestibility and voluntary intake (VI) of reed canarygrass (RC) and tall fescue (TF) pastures were studied in June, late July, early October, early November, and late November. Three applications of nitrogen (N), totaling 314 kg/ha, were made. Relationships were established between fecal N and DM digestibility by feeding freshly cut forage to steers indoors. Chromic oxide was administered daily to grazing steers, feces were sward sampled, digestibility of grazed forage was predicted, and VI estimated. Data are also presented on yield, percentage DM, percentage and apparent digestibility of crude protein, and nutritive value.In only one instance, early October, was TF superior to RC in VI, although TF was more digestible in all periods except June. In June, TF was more mature, and its digestibility and VI were less than RC. In late July, grazing steers consumed less TF in spite of its higher digestibility, compared with RC regrowth and wth first‐growth TF. In early November, TF was superior to RC in digestibility, VI, percentage crude protein, and yield. In late November, however, TF was lower than RC in VI and crude protein, findings difficult to explain. Dry matter digestibility and VI values were more closely related for RC than TF. Voluntary intake of steers grazing TF was more variable than the predicted digestibility. Thus, although digestibility is a good measure of nutritive value in RC, it does not seem so for TF.
Cation‐Anion Balance in Crops as a Factor in Determining the Effect of Nitrogen Fertilizers on Soil Acidity1
Authors: Pierre W. H. , Meisinger John , Birchett J. R. 
Published: July 2010

AbstractThe quantitative effect of crops on the acidity produced in soils from nitrification of NH4NO3 fertilizer was determined by growing oats and. buckwheat in the greenhouse and finding the amounts of CaCO3 necessary to bring the soils back to their original pH. Three crops of each plant species were grown, and the plants were analyzed for total N, nitrate‐N, and excess base. Determinations of pH were made both in 0.01 M CaCl2 and in H2O, with modifications to eliminate errors due to soluble salts.The acidity developed from NH4NO3 in uncropped soil was almost equal to the theoretical amount that should be developed by nitrification. Without the removal of soluble salts erroneous values were obtained. The increase in acidity due to N4NO3 when oats was grown lower than the theoretical value in the absence of a crop by 27%, and the increase in acidity with buckwheat was higher than the theoretical value by 87%. Analyses of the crops showed that the deviations from the theoretical increase in soil acidity from NH4NO3 fertilizer was quantitatively explained by the numbers of chemical equivalents of N and excess bases taken up by the crops, excess base being defined as total cations (Ca++ Mg++, K+ and Na+) — total anions (C1‐, SO4‐, and H2PO4‐).
Management Effects on Forage Production and Digestibility of Yuchi Arrowleaf Clover (Trifolium vesiculosum Savi)1
Authors: Hoveland C. S. , Carden E. L. , Anthony W. B. , Cunningham J. P. 
Published: July 2010

Abstract‘Yuchi’ arrowleaf clover (Trifolium vesiculosum Savi) produced more tillers and remained productive longer when cut at 1‐, 2‐, or 3‐week intervals than at 4‐, 5‐, or 6‐week intervals. Total yields were higher from less frequent cutting. Digestible dry matter (DDM) was high from December to maturity in June under all cutting frequencies. Stems of arrowleaf clover were higher in DDM than crimson clover (Trifolium incarnatum L.).
Herbicides and Nitrogen Fertilizer for the Establishment of Three Varieties of Spring‐sown Alfalfa1
Authors: Peters E. J. , Stritzke J. F. 
Published: July 2010

AbstractWe evaluated the effects of ammonium nitrate fertilizer on yields and stands of three varieties of seedling alfalfa (Medicago sativa L.) when these were treated and also not treated with preplant applications of 3.3 kg/ha of ethyl N,N‐dipropylthiocarbamate (EPTC). Alfalfa was sown in April. In two experiments we applied an overall treatment of 0.55 kg/ha of 4‐(2,4‐dichlorophenoxy)butric acid (2,4‐DB) to control broadleaf weeds. EPTC controlled weeds and increased yields of alfalfa, except when injury from EPTC occurred. Ammonium nitrate tended to reduce stands of alfalfa. Ammonium nitrate increased yields of Vernal and Du Puits, but not Ranger, when weeds were controlled with EPTC. Seedling alfalfa may not have fully responded to ammonium nitrate on EPTC plots because EPTC caused some injury to alfalfa and the fertilizer increased competition from broadleaf weeds.
Effect of Simazine on Protein Content of Rice Grain (Oryza sativa L.)
Authors: Vergara B. S. , Miller M. , Avelino E. 
Published: July 2010

AbstractAlthough simazine application to flooded soil at flowering time increases the percent protein in the rice grain, it is accompanied by a decrease in grain yield which can be attributed to increased sterility. This decrease in grain yield consequently lowers the total grain protein production per crop.Application of simazine to young rice plants grown in culture solution increased the nitrogen content of the blades, sheaths plus culms, and roots. The increase, however, is not the result of an increase in nitrogen uptake by the rice plant. The reduction in dry weight accounts for the increase in percent nitrogen.
Oxygen Diffusion in the Soil‐Plant System III. Oxygen Concentration Profiles, Respiration Rates, and the Significance of Plant Aeration Predicted for Maize Roots1
Authors: Luxmoore R. J. , Stolzy L. H. , Letey J. 
Published: July 2010

AbstractOxygen concentration profiles, mean respiration rates, and the percent plant aeration estimates (proportion of respired oxygen diffusing from the atmosphere via gas spaces in the plant) were obtained from an analysis of steady state oxygen diffusion in maize (Zea mays L.) root models under simulated field conditions.An increase in root radius and in water film thickness as occurs after rainfall or irrigation induced a decrease in oxygen concentration within the root, a decrease in mean respiration rate, and an increase in percent plant aeration (PPA). An increase in root length reduced both mean respiration rate and PPA. The mean respiration rates calculated for the various models were about half of the maximum rate for mature root tissue, indicating that oxygen concentration is the main factor limiting respiration rate under the simulated field conditions.Plant aeration increased markedly with increase in root porosity and this was accompanied by a higher oxygen concentration profile in the root and a small increase in mean respiration rate. Changes in the respiration or root wall permeability had minor effects on PPA.Under conditions which simulate the growth of adventitious roots of maize (0.05‐cm root radius and 20‐cm root length), PPA is 34% for a well aerated soil (0.01‐cm water film) and 42% for a soil which is oxygen deficient (0.05‐cm water film). Plant aeration is thus predicted to be a significant factor in the oxygen relations of maize roots. For a given root system, the gas‐filled porosity and the thickness of the water film around the root have the greatest influence on this process. Soil aeration is important in the oxygen supply to the lower root and root tip regions and thus has a critical effect on continuing plant growth and development.
Sodium and Potassium Interactions in Increasing the Salt Tolerance of Atriplex halimus L.: II. Na+ and K+ Uptake Characteristics
Authors: Mozafar Ahmad , Goodin J. R. , Oertli J. J. 
Published: July 2010

AbstractAbsorption of Na+ and K+ by Atriplex halimus from solutions with varying concentrations of Na+, K+, or Na+ + K+ were studied. In contrast to most plants, Na+ absorption by A. halimus was not inhibited by high concentrations of K+ in the culture solution. On the other hand, K+ absorption was greatly reduced by excess Na+ in the growing medium. If Na+ and K+ were present at equal concentrations, Na+ uptake was twice as great as K+. A specific site for Na+ absorption which is not inhibited by excess K+ in A. halimus was postulated. The results of previously reported work, in which it was shown that the presence of equal parts of Na+ and K+ in the culture solution resulted in the tolerance of plants to lower external osmotic potential and also higher yield, was discussed in light of the presence of higher Na+ and K+ content of the leaves. The presence of a biochemical interaction between Na+ and K+ which becomes operative only when both ions are present in adequate amounts is postulated. Higher yields and tolerance to lower external osmotic potential are thought to be the final manifestation of such a biochemical interaction.
Influence of Temperature on the Yield and Chemical Composition of Five Forage Legume Species1
Authors: Smith Dale 
Published: July 2010

AbstractOne‐year‐old plants of ‘Vernal’ alfalfa, ‘Lakeland’ red clover, ‘Common’ alsike clover, ‘Empire’ birdsfoot trefoil, and ‘Goldtop’ biennial sweetclover were grown to first flower in four temperature regimes: (a) 32 C, day/27 C night, (b) 27/21 C, (c) 21/15 C, and (d) 15/10 C. Flowering was delayed as temperatures decreased, except for trefoil and sweetclover where flowering occurred first in (b). Herbage, root, and total plant dry matter yields increased as temperatures decreased, except for trefoil in (a) where maturity was delayed and yields were as large as in (d). Average shoot height of red and alsike clovers and sweetclover increased as temperatures decreased, but changed little with trefoil. Shoot height of alfalfa was greatest in (b). Numbers of shoots were not affected by temperature, except in alsike clover where they increased as temperature decreased. Influence of temperature on chemical composition of the herbage and on carbohydrate storage in the roots is discussed. It was noteworthy that K concentration was very low in the herbage grown at the coldest temperatures (d) where the average for all species was 1.4% as compared with 2.3% in the herbage from (b).
Differential Response of Rice Varieties to Timing of Mid‐season Nitrogen Applications1
Authors: Wells B. R. , Johnston T. H. 
Published: July 2010

AbstractField studies were conducted with rice (Oryza sativa L.) on Crowley silt loam soil using the important commercial cultivars ‘Bluebelle,’ ‘Nova 66,’ and ‘Starbonnet.’ We studied the effects of rate and timing of mid‐season N applications on grain yield, plant height, lodging, head‐rice yield, and grain weight (g/M) of varieties (cultivars) differing in maturity and plant type. All plots received 45 kg/ha of N as ammonium sulfate 15 days after seedling emergence, just before initial flooding. The remaining N needed to give total rates of 78, 112, or 146 kg/ha was applied to drained soil at specified intervals near midseason. Fifteen main stems, selected at random from the outside rows of each plot at the time of mid‐season N application, were used for determining internode lengths.Maximum grain yields were associated with N applied at median internode lengths averaging 21.0, 58.5, and 5.0 mm for Bluebelle, Nova 66, and Starbonnet, respectively. Delaying mid‐season N applications until these respective stages of plant development, resulted in shorter plants and less lodging, accompanied by increased grain weight and head‐rice yields.Variations in the median internode length at N fertilization, timed for a combination of maximum grain yield and minimum plant height and lodging, were closely associated with plant type. Starbonnet and Bluebelle, which have short, stiff straw and erect leaves, responded better to N applied at a shorter internode length than Nova 66, a taller, broader‐leaved variety. When N was applied too early, Nova 66 produced considerably more excessive vegetation than did Bluebelle and Starbonnet. Both Starbonnet and Bluebelle have plant types which approach the one currently favored by many plant breeders.
Sunflower Date of Planting and Chemical Composition at Various Growth Stages1
Authors: Robinson R. G. 
Published: July 2010

AbstractSix sunflower (Helianthus annuus L.) varieties were planted at seven dates ranging from April 24 to June 28,1967 through 1969. Early May plantings produced highest seed yields, hectoliter weights, oil percentages, and large seed percentages. Days from planting to emergence and emergence to flowering decreased from early to late planting dates. Date of planting was the variable which most consistently affected seed yield. It overshadowed both varieties variation and the interaction of dates ✕ varieties.Whole plant samples for N, S, P, K, Ca, Mg, Fe, Na, Sr, Zn, Cu, Mo, Mn, and B analyses were taken at 13 different growth stages and separated into root, stem‐leaves‐receptacle, and seed. Comparative data for seedling, heading, flowering, and maturing periods of growth showed concentrations of most elements declined with age in stems‐ leaves‐receptacle.Variation in composition of stem‐leaves‐receptacle among growth stages was greater than among varieties, but this relationship was reversed in seed. Seed; stemleaves‐receptacle, and root differed in composition and in relative rank of the elements.
A Simple Turbidimetric Method of Determining Total Sulfur in Plant Materials1
Authors: Tabatabai M. A. , Bremner J. M. 
Published: July 2010

AbstractA rapid method of determining total sulfur in plant materials is described. The plant material is digested in a volumetric flask with nitric and perchloric acid, and the sulfate content of an aliquot of the digest is determined turbidimetrically as BaSO4 by a barium chloride‐gelatin procedure. The method is simple and precise, and its results agree closely with those obtained by the Johnson‐Nishita method.
Mulches for Grass Establishment on Fill Slopes1
Authors: Dudeck A. E. , Swanson N. P. , Mielke L. N. , Dedrick A. R. 
Published: July 2010

AbstractEleven mulch treatments were evaluated during the fall of 1966 on a 2:1 northeast‐facing fill slope seeded to smooth bromegrass (Bromus inermis Leyss.). Mulch materials included wood cellulose fiber, excelsior, jute netting, emulsifiable asphalt used separately and as an anchorage for corncobs, woodchips, prairie hay, and fiberglass. Plots protected with an excelsior mat yielded the best seedling grass.Eight mulch treatments were evaluated on a 2:1 east‐facing fill slope during the fall of 1967. Mulch materials included an emulsifiable polymer, compost, wood cellulose, jute netting, excelsior, and asphalt‐anchored mulches of excelsior, woodshavings, and bark dust. Plots protected with an excelsior mat or jute netting yielded the best seedling grass.
Nitrogen Metabolism in Atriplex polycarpa as Affected by Substrate Nitrogen and NaCl Salinity1
Authors: Chatterton N. Jerry , Goodin J. R. , Duncan Cameron 
Published: July 2010

AbstractNitrogen metabolism and growth responses of desert saltbush (Atriplex polycarpa) were studied using various combinations of nitrogen and sodium chloride in the growing medium. Plant yields were reduced with high levels of either N or NaCl and were further reduced when both N and NaCl were present at high concentrations. Nitrate accumulated in the plant tissues sufficient to be a problem for grazing animals only when the growth medium contained .045 M nitrogen. Total‐nitrogen and protein‐nitrogen were both relatively high, ranging from 2 to 8% (dry wt.) among the treatments. Although some non‐salt‐tolerant plant species accumulate non‐protein‐nitrogen when grown in a saline medium, we found no such increase in desert saltbush. We believe that salt tolerance in desert saltbush is the result of anatomical adaptations in combination with a high protein and low non‐protein‐nitrogen content.
N, P, and K Percentages in Soybean (Glycine max (L.) Merrill) Plant Parts1
Authors: Hanway J. J. , Weber C. R. 
Published: July 2010

AbstractField experiments were conducted with N fertilizer applications for nodulating and non‐nodulating soybean isolines, with P and K fertilizer applications for the nodulating isolines, and with 8 varieties. Percentages of N, P, and K in the plant parts at successive stages of plant development were determined. Composition of plant parts from different varieties usually were similar. N, P, and K concentrations in each plant part, except the seeds, usually decreased as the season progressed. Fertilizer applications resulted in increased concentrations of the fertilizer nutrient applied in all plant parts. N deficiency resulted in late‐season increased P concentrations, especially in leaves, petioles and seeds. Nutrient translocation to the developing seeds resulted in severe nutrient depletion in other plant parts irrespective of fertilizer applications.
Soil Temperature and Wheat Straw Mulch Effects on Wheat Plant Development and Nutrient Concentration1
Authors: Smika D. E. , Ellis R. 
Published: July 2010

AbstractHard red winter wheat (Triticum aestivum L.) was grown with and without wheat straw mulch on the soil surface both in a growth chamber with controlled soil temperatures and in the field where soil temperatures were measured at the crown depth. Concentrations of N, P, K, Ca, Mg, Fe, Zn, Mn, and Cu in the plant were determined at the end of tillering and at heading.Wheat plants grown with soil temperatures below 10C for 50 days, whether in the growth chamber or in the field, had 2 to 3 fewer tillers per plant and 0.5 to 1.2 fewer heads per plant than plants grown with soil temperatures below 10C for only 15 days. Soil temperature seemed not to affect weight per head or total plant weight. Cooler temperatures reduced the concentrations of only K and Fe in the growth chamber at heading and N in the field at heading. When mulched and bare soil temperatures were identical, mulch did not reduce numbers of tillers or heads per plant, plant nutrient concentration, total uptake of any nutrient, or final grain yields in growth chamber or field. The concentration of all nutrients but Cu changed as the plant developed showing the necessity of knowing growth stages of plants if nutrient concentrations are to be compared.
Influence of Spring Mowing on Reseeding and Productivity of selected Annual Clovers in a Grass Sod1
Authors: Knight W. E. 
Published: July 2010

AbstractIn a 3‐year experiment, we studied the effects of three spring mowing treatments on reseeding of selected varieties of crimson, arrowleaf and subterranean clovers grown in a coastal bermudagrass (Cynodon dactylon (L.) Pers.) sod. Mowing on April 25 prevented satisfactory reseeding of crimson clover (Trifolium incarnatum L.) and greatly reduced reseeding of arrowleaf clover (Trifolium vesiculosum Savi.). Clipping on May 25 prevented effective reseeding of arrowleaf clover but provided best reseeding of crimson clover. Subclover (Trifolium subterraneum L.) reseeded well under all three spring mowing treatments. Careful grazing management of crimson and arrowleaf clovers will be required after April 1 if reseeding is desired. Under conditions of spring drought, overgrazing may reduce regrowth and seed production and cause stand failures in the succeeding year. Properly managed winter‐annual clovers not only produced forage of high quality in the winter and spring, but also increased production of the associated grass.
Factors Affecting the Spectral Properties of Leaves with Special Emphasis on Leaf Water Status1
Authors: Carlson Richard E. , Yarger Douglas N. , Shaw Robert H. 
Published: July 2010

AbstractLeaf structure and water content constitute major factors affecting the interaction of radiant energy with leaves in the wavelength region from 800 to 2,600 mµ. Reflectivity, Rλ, and transmissivity, T», were measured in this wavelength region for leaves from three crop species (corn, Zea mays; soybean, Glycine max; sorghum, Sorghum bicolor). Absorptivity, Aλ, was calculated from measurements of Rλ and Tλ. The spectral responses (R», Tλ, or Aλ ) at six wavelengths (maxima and minima of the reflectivity curve) regressed on relative leaf water content (RWC) and specific leaf densities (mg/cm3) were highly correlated. A highly significant relationship between leaf RWC and the spectral response (RΔλ) over lour wide‐wavelength intervals is also reported.
A Method for Determining Aluminum Response of Barley in Nutrient Solution in Comparison to Response in Al‐Toxic Soil1
Authors: Reid David A. , Fleming A. L. , Foy C. D. 
Published: July 2010

AbstractA method was developed to screen barley populations for Al response in nutrient cultures. Thirty varieties and selections were grown in tanks of nutrient solutions containing either O or 4 ppm Al at initial pH 4.8. Aluminum tolerance ratings obtained by this method were in good agreement with those obtained previously in pots of acid, Al‐toxic soils in the greenhouse and in field plots. In general, Al injury was characterized by an increase in the number of roots and a decrease in root length and root weight per plant. Highly significant (1% level) correlation coefficients were found between root length and weight (r=0.93); root weight and number of roots (r=−0.76); and root length and number of roots (r=−0.83). The correlation coefficient between root weight in solution and in soil (r=0.75) was also significant at the 1% level. The method presented is satisfactory for screening barley varieties for Al tolerance.
Interaction of Water Uptake and Root Distribution1
Authors: Molz Fred J. 
Published: July 2010

AbstractA simplified version of a mathematical model developed by Molz and Remson (1970) is used to compute “effective root distribution” for sorghum. Data from an experiment by Gardner (1964) are utilized in the computation, and the computed root distribution is compared with the measured distribution. The effective distribution is computed for 1, 3, 5, and 7 days after the beginning of the experiment, and results indicate that it is a complex quantity which varies in both space and time. Initially, the two distributions bear little resemblance, but as the soil dries due to transpiration, they become quite similar. The computations lend support to the model of Molz and Remson (1970) and might be interpreted as indicating the existence of significant impedence to moisture flow in the plant roots under moist conditions. Longitudinal variations in root surface permeability and root growth could also contribute to the computed behavior.
Influence of Soil Fe and MnEDTA Interactions upon the Fe and Mn Nutrition of Bean Plants1
Authors: Knezek B. D. , Greinert H. 
Published: July 2010

AbstractSeveral combinations of inorganic and chelated (EDTA) Fe and Mn were added to Mn‐deficient Houghton muck. Navy bean (Phaseolus vulgaris L.) growth, nutrient uptake, and Fe:Mn ratios were obtained on two successive crops in the greenhouse. Exchangeable Fe and Mn and easily reducible Mn were determined on the soil after the second crop. Addition of MnEDTA or FeEDTA to the soil intensified visual Mn‐deficiency symptoms, reduced growth, and reduced Mn uptake while the Fe concentration remained relatively constant, resulting in a wide Fe:Mn ratio in plants grown in the presence of EDTA. Soil ammonium acetate‐extractable Mn and Fe values indicated that Fe increased by a factor of 20 in the presence of EDTA, while Mn did not change. The ineffectiveness of MnEDTA in overcoming plant Mn deficiency was due to a rapid substitution of Fe for Mn in the EDTA molecule with probable inactivation of the released Mn by complexing with organic matter. Hence, the aggravation of an already critical Fe:Mn ratio in the soil was accomplished, less Mn was taken up by plants, and Mn deficiency was intensified with the use of MnEDTA.