bluuebunny/crossref_metadata_2025_split huggingface dataset:
Higher Fatty Acid Composition of Immature Forages as Affected by N Fertilization1
Authors: Mayland H. F. , Molloy L. F. , Collie T. W. 
Published: July 2010

AbstractHigh levels of both N and total higher fatty acids (HFA) in forage have been associated with increasing the grass tetany hazard to grazing cattle. The objective of this study was to determine the relationship between forage N, total HFA, and HFA species distribution in several forages.Forage N, HFA, HFA species concentration, and total chlorophyll were determined in immature vegetative growth of Agropyron desertorum (Fisch.) Schult., Cynodon dactylon L., Lolium perenne L., Trifolium repens L., and Triticum aestivum L. established with soil fertility levels up to 500 ppm N in the growth chamber. Forage HFA concentrations were positively and linearly related to forage N levels, but regression coefficients were not the same for all species. The HFA concentrations were as high as 16 mmol COOH/100g DM at 6% total N in first cutting Lolium perenne L. The relative HFA species distribution was the same within a given forage, even though total N concentrations ranged from 2 to 6%. The mean HFA specie concentrations (determined by gas‐liquid‐chromotography relative to mean total HFA concentrations determined by titration) when expressed as percent for the grasses were: C14:0 — 2%, C16:0 — 13%, C16:1 — 1%, C18:0 plus C18:1 — 1%, C18:2 —11%, and C18:3 — 67%. The total HFA concentrations were positively correlated with chlorophyll a + b concentrations which was expected, since the HFA of green plants is largely associated with chloroplast membrane.
Response of Soybean Cultivars to Narrow Rows and Planting Rates Under Weed‐free Conditions1
Authors: Cooper R. L. 
Published: July 2010

AbstractWith continued development of new and better herbicides for chemical weed control in soybeans, the potential exists for growing soybeans in very narrow rows (17 cm) without cultivation. The objective of this research was to examine the potential yield of soybeans [Glycine max (L.) Merr.] in 17‐cm rows under weed free conditions and also to determine the optimum seeding rate and relative yield of this row width compared to greater row widths.Up to nine cultivars were grown in three different row widths and at five different populations in field plots in central Illinois over a period of 6 years. When seeding rate was low enough to prevent lodging, yield advantages of 10 to 20% (3 to 6 q/ha) were obtained from planting in 17‐cm rows compared to 50‐ or 75‐cm rows. Earlier maturing cultivars tended to be more responsive to 17‐cm rows, and under high yield conditions and irrigation, 30 to 40% (9 to 12 q/ha) yield responses were observed with one of the more responsive cultivars. The combination of early cultivars in 17‐cm rows provided the highest absolute yields. A seeding rate of 37.5 viable seeds per m2 was near optimum for most cultivars and for all three row widths tested. These results suggest that if an effective weed control program can be developed to control weeds in soybeans without cultivation, there would be a significant yield advantage from planting soybeans in 17‐cm rows.
Healing Potential of Creeping Bentgrass as Affected by Nitrogen and Soil Temperature1
Authors: Hawes D. T. , Decker A. M. 
Published: July 2010

AbstractMaintenance of creeping bentgrass putting greens in the transition zone between the northern cool season grass region and the southern warm season grass region is difficult during July and August due to high temperatures. A management study on soil temperature plots with several N sources and levels was thought to be a suitable method of finding solutions to this maintenance difficulty. This paper reports the effects of N levels and temperature on what we have chosen to call healing potential.‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) was maintained on field soil temperature plots with target temperatures of 32, 21, ambient and 10 C. The soil was a Sassafras silt loam (Typic Hapludults). Response to N from two sources was compared at three levels in five fertilizer treatments. The healing potential of the turf was determined by visually estimating the 3‐week growth of stolons from the surrounding turf as percent cover that developed into a 4.8 cm diameter bare area. Healing potential was compared with clipping yields which were taken from sub‐plots (N sources).Healing was best under conditions of warm temperatures (ambient, 21 and 32 C) and high N levels for three dates in June and July. However, an adverse effect of high N was found at the 32 C soil temperature for three dates in August. Healing potential was closely related to clipping yield. Their linear correlation values ranged between + 0.82 and + 0.92. Clipping yields were found to be a good indicator of the healing potential of creeping bentgrass turf.
Fall‐ vs. Spring‐applied Sulfur‐coated Urea, Uncoated Urea, and Sodium Nitrate for Corn1
Authors: Frye W. W. 
Published: July 2010

AbstractThe practice of applying fertilizer in the fall for crops grown the next summer is advantageous to the fertilizer manufacturing and marketing sector as well as saving time for farmers in the spring planting season. Sulfur‐coated urea (SCU), NaNO3, and uncoated urea were applied in field experiments during 1972‐74 to compare their efficiency in fall application with spring application for the production of corn (Zea mays L.) grain on a Mountview silt loam soil (Typic Paleudult, fine silty, siliceous, thermic) at Cookeville, Tenn. Two dissolution grades of SCU were compared with NaNO3 and uncoated urea, at rates of 112 and 224 kg N/ha in 1972‐73 and 168 and 224 kg N/ha in 1974. Grain yields were measured and relative efficiency of fall application and response to rates, sources, and dates of application were calculated. Soil concentrations of ammonium and nitrate N were measured on some treatments. Soil temperature at 10 cm depth was recorded during the winter and early spring of 2 years.There were little or no differences in corn grain yields between fall and spring applications of N at the 224 kg/ha rate. At the lower N rates, spring‐applied N increased yields compared to fall‐applied N. The relative efficiency of fall compared to spring application of the materials, averaged for 3 years, was 0.52 and 0.86 for NaNO3 at 112 and 224 kg N/ha respectively, 0.49 and 0‐95 for uncoated urea, 0.80 and 1.10 for SCU‐1, and 0.72 and 1.03 for SCU‐2. Nitrates leached to a depth of 45 cm or more during the winter and early spring in plots treated with NaNO3 and uncoated urea. Conditions were probably favorable for a slow but significant dentrification rate at times during the winter and early spring, leading to the belief that dentrification may have caused some of the decreased efficiency of fall‐applied N.Although SCU was more effective than NaNO3 or uncoated urea, fall‐applied N from any fertilizer source would be less effective on subsequent spring and summer growth than spring‐applied N under similar soil and climate conditions.
Role of Changes in Solute Concentration in Maintaining Favorable Water Balance in Field‐Grown Cotton1
Authors: Cutler J. M. , Rains D. W. , Loomis R. S. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) shows various adaptive responses to water deficits, including alterations in cellular osmotic concentrations. The role of changes in solute concentration in maintaining favorable water balance in field‐grown cotton was evaluated under wet and dry irrigation treatments. The experiments were conducted with a fine loamy mixed, calcareous thermic‐Typic Torriorthents soil in a semi‐arid environment. Leaf diffusive resistance, measured by a resistance porometer, was unaffected by leaf water potential (down to −29 bars in adapted leaves of the dry treatment) while the typical response to light was maintained. Leaf blade elongation rate was less in plants with low leaf water potential. The rate was maximal in the early evening and depressed during the midday water potential minimum and at night. Some blade enlargement occurred during time intervals when leaf water potentials were as low as −19 to −23 bars. The osmotica of primary importance in cotton leaves were K, nitrate, citrate, malate, and sugars; K and other soluble inorganic leaf constituents did not vary diurnally or with plant status. In contrast, sugar and malate concentrations (expressed on a dry weight basis) were 20 to 60% greater in leaves from the dry treatment than in leaves from the frequently irrigated treatment. In addition, diurnal variations in sugars and malate followed the variation in leaf water potential, with a slight lag, and a simple model of leaf osmotic relations suggested that these accounted for 10 to 40% of the diurnal changes in the calculated osmotic potential. A diurnal hysteresis of as much as 7 bars was observed in the relation between water potential and relative water content due largely to changes in the elasticity of cell walls. We conclude that the maintenance of low leaf diffusive resistance and continued leaf elongation despite reductions in leaf water potential indicates that turgor is also maintained. This was due partly to the accumulation of sugars and malate and partly to high cell wall elasticity.
Aluminum Tolerance of Soybean Cultivars Based on Root Elongation in Solution Culture Compared with Growth in Acid Soil1
Authors: Sartain J. B. , Kamprath E. J. 
Published: July 2010

AbstractGrowth of soybean [Glycine max (L.) Merr.] roots into acid subsoils and utilization of subsoil moisture is limited in many soils of the southeastern U. S. because of Al toxicity. Laboratory and greenhouse experiments were conducted to obtain information on tolerance of soybean cultivars which would be helpful in selection of cultivars best adapted to acid subsoils. Root elongation measurements were made of 18 cultivars exposed for 48 hours to solutions containing 0, 0.25, 0.50, and 1.0 ppm Al and 10 ppm Ca. Eleven of the cultivars were selected for a greenhouse experiment in which plants were grown in a Lynchburg soil (Aerie Paleaquult) at 81 and 4% Al saturation. Measurements were made of top growth, root length, and the Ca, P, and Al concentrations of the plant tissue. Of the 11 cultivars used, ‘Lee’, ‘Lee 68’, ‘York’, ‘Ogden’, and ‘Dare’ were judged to be relatively Al tolerant according to the short term root elongation studies. Based on absolute top growth in the 81% Al saturated soi1 or relative top growth in the 81% Al saturated soil as compared with the 4% Al saturated soil the cultivars Lee, ‘Bragg’, ‘Pickett 71’, and York were more tolerant of Al than the other cultivars.
Zinc Nutrition of Rice as Influenced by Rates of Gypsum and Zn Fertilization of Alkali Soils1
Authors: Takkar P. N. , Singh Tarjit 
Published: July 2010

AbstractThree field experiments were conducted on Zn deficient alkali soils, two on Natraquic calciorthids, and one on Aquic Camborthids, to determine the effect of gypsum and Zn fertilization alone and in combination on the Zn nutrition of rice IR 8 (Oryza sativa L.). Three rates of gypsum (0, 25, and 50% gypsum requirement of soil) and three rates of Zn (0, 11.2, and 22.4 kg Zn/ha, as ZnSO4‐7H2O) and their possible combinations were tried. At all the three locations, the growth of the rice crop was very poor and exhibited Zn deficiency symptoms in control plots. The yield and Zn uptake was higher in alkali soil high in CaCO3 and low in pH than in soils low in CaCO3 and high in pH. Gypsum application markedly decreased the soil pH, and significantly increased the yield and Zn uptake by rice. This resulted from a marked significant increase in soil and plant Zn concentration, though it remained within marginal levels. Zinc application decreased the pH, but not so appreciably as did gypsum; and markedly increased the available Zn from deficient to adequate levels. This in turn significantly increased Zn concentration and its uptake and resulted in a significant increase in rice grain and straw yield both over control and gypsum treatments. Optimum response of rice to Zn was observed at 11.2 kg Zn/ha except in one of the Natraquic calciorthids where it was 22.4 kg Zn/ha. Gypsum in conjunction with Zn application did not increase either the available Zn or the rice yield. The beneficial effect of Zn application to rice grown on the alkali soils under investigation was far more than that of gypsum.
Animal Preference, Nutritive Attributes, and Yield of Pennisetum flaccidum and P. orientale1
Authors: Burns J. C. , Timothy D. H. , Mochrie R. D. , Chamblee D. S. , Nelson L. A. 
Published: July 2010

AbstractWarm‐season perennial grasses can make an important contribution to animal enterprises by providing forage for summer grazing. In the transitional belt, however, where cool and warm‐season grasses are used during the grazing season; both are hampered by periods of belownormal growth and frequently only the warm‐season species are available during midsummer. Six Pennisetum accessions initiated growth earlier in the spring in North Carolina than traditional warm‐season grasses, and continued growing through summer and into the fall until killed by frost. The objectives of this study were to evaluate these accessions for acceptance by free‐grazing animals, nutritive attributes, dry matter yield, and persistence. Plantings were made on a loam soil (Typic Hapludult, in the Clayey, Kaolinitic, Thermic family). Five accessions of Pennisetum orientale Rich (from India) and one selection of Pennisetum flaccidum Griseb. (from Afghanistan) were evaluated in one experiment (2 year study) for animal preference and associated nutritive value. Animals grazed all selections (each time forage reached 46 to 61 cm) but consistently preferred (P ≤ 0.01) P. flaccidum. In vitro dry matter disappearance (IVDMD) differed significantly among selections, but rank was not consistent from year to year. IVDMD ranged between 63.1 and 70.4%. Ranges for neutral detergent fiber (NDF) were: 55.0 to 57.9%; for acid detergent fiber (ADF), 28.5 to 34.1%; for lignin, 2.66 to 4.48%, and for N 2.95 to 3.78%. In a separate trial, dry matter yields (3‐year avg.) of the five P. orientale selections under a “short cut” regime (46 to 74 cm high cut to a 15‐cm stubble) were 7,948 kg/ha and for “tall cut” regime (76 to 102 cm tall cut to a 15‐cm stub ble) 12,393 kg/ha. P. flaccidum averaged 8,958 and 12,003 kg/ha for short cut and tall cut, respectively. Yields exceeded 15,700 kg/ha for several of the P. orientale selections managed under the tall cut regime. P. flaccidum produced more of its seasonal yield earlier (91% by 25 July) than did the P. orientale selections (only 77% by 25 July). The nutritive attributes of these forages were appreciably reduced by maturity. Mean values for the five P. orientale selections for the short and tall cut regimes and for P. flaccidum for each harvest regime respectively, were as follows: IVDMD 48.4, 44.0 and 54.7, 54.5%; NDF 61.4, 65.4 and 60.5, 61.1%; ADF 32.8, 35.8 and 33.9, 32.9%; lignin 3.07, 3.84 and 3.67, 3.30%; and N 2.39, 1.77 and 2.44, 2.13%. The Pennisetum accessions evaluated have potential as forage species in the southeastern U.S. In addition to their long growing season and high yield potential, their NDF concentrations were low compared with Coastal bermudagrass (Cynodon dactylon L.). This was especially noticeable in the more mature harvests. Such low fiber concentrations may contribute to an increased dry matter intake by grazing animals.
Photosynthetically Active Radiation, CO2 Uptake, and Stomatal Diffusive Resistance Profiles Within Soybean Canopies1
Authors: Hatfield J. L. , Carlson R. E. 
Published: July 2010

AbstractProfiles of PPFD (photosynthetic photon flux density), CO2 uptake and stomatal diffusive resistance were measured in field‐grown canopies of Hark and Rampage soybeans [Glycine max (L.) Merr.]. These studies were conducted to examine and quantify the relationships between these parameters over the daylight period for discrete canopy stratum and the complete canopy. Measurements were made in the field with soybeans grown on a Huntsville silt loam. CO2 uptake was measured with a field portable 14CO2 leaf exposure chamber, PPFD with a quantum sensor attached perpendicularly to the chamber and stomatal resistance with a diffusion porometer. Each of the measurements was made within four strata of both canopies at various growth stages and under varying atmospheric conditions. Canopy distributions of CO2 uptake showed that most photosynthate was produced in the upper 20% of the canopies. This is approximately one‐third of the total canopy LAI (leaf area index) and represents the level of 90% interception of incident photosynthetically active radiation. Regression analyses of the relationship between PPFD and CO2 uptake produced a linear model, and the slope of the line was dependent upon the day. The variation between days was caused by environmental conditions, which reduced CO2 uptake by increased stomatal diffusive resistance. These reductions in CO2 uptake were caused by soil moisture stress and cold temperature shock. Hark exhibited the greater CO2 uptake rates and also the largest reduction in uptake with increased stomatal diffusive resistance. Stomatal diffusive resistance profiles showed an increase with canopy depth in both cultivars; this was attributed to low PPFD. Major photosynthetic production by soybean canopies occurs in the upper portion of the canopy and further understanding of the relationship between canopy behavior and the environment may lead to increased crop production.
Evaluation of Commercial and Experimental Three‐Way Corn Hybrids for Aflatoxin B1 Production Potential1
Authors: Widstrom N. W. , Wiseman B. R. , McMillian W. W. , Kwolek W. F. , Lillehoj E. B. , Jellum M. D. , Massey J. H. 
Published: July 2010

AbstractClimatic conditions in the southeastern U.S. frequently favor infection by Aspergillus flavus Link ex Fr. and subsequent aflatoxin production on preharvest corn (Zea mays L.). Plant resistance to infection and toxin development in corn may be an important factor in reducing toxin levels. Ten full‐season and 10 short to mid‐season commercial corn hybrids from three locations in the Coastal Plain Region of Georgia were evaluated for aflatoxin concentration from natural infection by Aspergillus spp. over a 3‐year period. A higher incidence of aflatoxin positives and higher concentrations of toxin occurred at the Tifton, Georgia, location than at the Plains or Midville locations. Corn from plots infested with corn earworm, Heliothis zea (Boddie), had higher levels of toxin contamination than samples from noninfested plots. Significant differences for aflatoxin concentration occurred among the commercial hybrids sampled, but differences were not detected among dent or sweet corn inbreds tested as three‐way crosses. The lack of differences was generally attributed to insufficient replication and the possibility that the common single‐cross tester(s) had an extraordinary influence on aflatoxin production potential. Evaluation and selection for plant resistance to infection by A. flavus and aflatoxin production will probably be difficult.
Critical Boron Concentrations in Plant Tissues of Two Sunflower Cultivars1
Authors: Blamey F. P. C. , Mould Diana , Chapman J. 
Published: July 2010

AbstractMarked responses of sunflowers (Helianthus annuus L.) to boron fertilization have been recorded but little information exists on the B nutritional requirements of this crop. In order to study this aspect, field trials were conducted in which five rates of B fertilizer (0 to 4 kg B/ha) were applied to two cultivars, ‘Smena’ and ‘SO 320’, on two soil types. The cultivars differed in visual susceptibility to B deficiency in the vegetative stage but differed only slightly in B uptake. B fertilization increased seed yields by an average of 48% in both cultivars. To establish critical B concentrations in plant tissues, relationships were investigated between seed yield and the B concentrations in I‐mo‐old seedlings and in the topmost mature leaf at flowering. Seedlings proved unsatisfactory as index tissue, particularly with SO 320, but meaningful relationships were recorded between seed yield and B concentration in the topmost mature leaf at flowering in both cultivars. Critical concentrations in this tissue were determined as 32 and 35 ppm B for Smena and SO 320, respectively. No significant differences were recorded between the two cultivars in the relationship between seed yield and the B concentration in the leaf below the critical levels, and the data were combined. The critical concentration in the topmost mature leaf at flowering was determined as 34 ppm B for both cultivars, the confidence interval (95%) being from 31 to 38 ppm B.
Simulation of Soil Water within the Root Zone of a Corn Crop1
Authors: Radcliffe D. , Hayden T. , Watson K. , Crowley P. , Phillips R. E. 
Published: July 2010

AbstractKnowledge of the distribution and movement of soil water in the root zone of a row crop is important in farm and watershed management, and in research on the transport of soil nutrients and pollutants. The objective of this study was to develop a model that would calculate the infiltration, evaporation, transpiration, and deep drainage of soil water in the root zone of a corn (Zea mays L.) crop throughout a growing season, using readily obtainable climatic data as daily inputs. The model differed from existing models in that the effect on the distribution of rainwater due to channeling in the cracks and non‐capillary pores of a highly structured soil was considered. This distribution was obtained by adapting equations used to describe analagous distributions in ion exchange chromatography. Two methods of modeling plant uptake of soil water were compared. An empirical approach assumed that the plant took water from the layer in the root zone with the lowest energy level (determined four times daily) and the amount taken was given by a curve that related the ratio of actual and potential transpiration to the water content at that level. A mechanistic approach, similar to that used by Nimah and Hanks in 1973, considered root distribution, hydraulic conductivities, plant resistance, and root‐soil contact resistance.The model was tested using seasonal soil moisture records from 4 years on one soil and a single year on a second soil. Mean squared error of prediction for the seasons ranged from 0.05 to 0.15%. Use of the partial displacement infiltration component improved the accuracy of the results in all but one trial. The two methods of modeling plant uptake of soil water, mechanistic and empirical, differed very little in accuracy.