bluuebunny/crossref_metadata_2025_split huggingface dataset:
Periodic Changes in the Ionic Concentrations of Some Submerged Soils of Bihar1
Authors: Biswas D , Naphade J. D. , Dhua S. P. 
Published: July 2010

AbstractThe investigation was carried out under laboratory conditions to study the chemistry of submerged soils of Bihar to help in assessing their potentialities in meeting the nutritional requirements of the rice plant (Oryza sativa L.). The soils were kept at 1:1.5 soil:water ratio and analyzed periodically for pH, electrical conductivity, soluble NH4+, Fe++, Mn++, P, Na+ K+, Ca++, CO3=, HCO3−, and Cl− on the 15th, 30th, 45th, and 60th day. The results show differential release of these nutrients in different soils with time. While the pH of acidic soils increased, that of alkaline soils decreased with the time of submergence. The pH of all soils fell between 6.50 and 8.50 on the 60th day. In general the peak values of Mn++ and CO3 = were noted on the 15th day, HCO3− and Cl− on the 30th day, and that of NH4+ between the 30th and 45th day after submergence. Most of the soils appear to be inherently deficient in N, P, K, Fe++ etc. and a good response of rice to fertilizer applications may be expected.
Crop Response to Phosphate Fertilization and to Residual Phosphate Levels: I. Field Experiments1
Authors: Giskin M. , Hagin J. , Kafkafi U. 
Published: July 2010

AbstractIntensive phosphate fertilization practices over the last two decades have resulted in large quantities of phosphates accumulating in soils. The objective of two field experiments was to evaluate yield response to various levels of residual phosphorus.The experiments were carried out within an irrigated rotation having two crops per year. The initial experimental treatments consisted of four rates of superphosphate equivalent to 0, 48, 144, and 432 kg P/ha, applied prior to each of three crops. Following the harvest of the third crop the original plots were quartered and six additional crops were grown on each of the two soils. Superphosphate was added before the seeding of each crop in amounts equal to 0, 13, 26, and 52 kg P/ha.Out of the 18 crops harvested, there were only four yield responses to P fertilization significant at either the 0.05 or 0.01 level. The high initial residual P level (10‐11 ppm NaHCO3‐soluble P) and the low P fixing power of the soils (68 and 75% of the added P remained exchangeable) could explain the low frequency of response to phosphate fertilization. It was only after five to six successive crops were grown, that the bicarbonate‐soluble P in the control plots dropped below 8 ppm. In these cases plant response to residual P was found. Accepted agronomic fertilizer rates (13 to 52 kg P/ha) applied to crops 4 to 9 were capable of maintaining soil residual P levels between 6.3 and 17.5 ppm P (NaHCO3‐soluble). At residual P levels of 26.2 to 97.5 ppm P (NaHCO3‐soluble) similar fertilizer rates were not capable of maintaining or recharging the soil “phosphate pool” which had been achieved by the heavy fertilizations (48 to 432 kg P/ha) applied to crops 1 to 3.
Oxygen Diffusion in the Soil‐Plant System V. Oxygen Concentration and Temperature Effects on Oxygen Relations Predicted for Maize Roots1
Authors: Luxmoore R. J. , Stolzy L. H. 
Published: July 2010

AbstractA model for steady state isothermal oxygen diffusion into a cylindrical root surrounded by a uniform water film, accounting for longitudinal oxygen flux through intercellular gas spaces, radial flux through the water film, and a concentration‐dependent respiratory oxygen sink, was used to assess effects of change in soil and root oxygen concentration and temperature on the oxygen relations of maize (Zea mays L.) roots.Increases in both root oxygen concentration at 5 cm from the tip and in soil oxygen concentration increased the root oxygen profile. Under conditions of high soil oxygen concentration and low root concentration oxygen diffused back along the root toward the shoot. Change in root oxygen concentration (0.05 to 0.15 ml/ml) at cm from the root tip had only a small effect on the oxygen concentration at the root tip, whereas an increase in soil oxygen concentration (0.05 to 0.15 ml/ml) increased the root tip oxygen concentration (0.02 to 0.07 ml/ml). Respiration rate of the root tip (1‐mm section) was closely dependent on soil oxygen supply and plant aeration had very little effect. Plant aeration contributed significantly to the respiration rate on a whole‐root basis. Mean root respiration rate increased with increase in soil and root oxygen concentration and also with increase in temperature. The root oxygen concentration profile decreased with rise in temperature associated with an increased respiratory oxygen demand. For mean respiration rate Q10 was less than 2 and decreased with increase in temperature.
Comparison of Heavily Fertilized Pangolagrass and Stargrass Pastures under Humid Tropical Conditions1
Authors: Caro‐Costas Rubén R. , Abruña Fernando , Vicente‐Chandler José 
Published: July 2010

AbstractThere is little information on the comparative productivity of intensively managed pastures of pangolagrass (Digitaria decumbens) and stargrass (Cynodon Niem fuensis) under humid tropical conditions.Therefore, an experiment was conducted to compare the productivity of these grasses growing on a steep ultisol when fertilized with 2.2 metric tons of 14‐4‐10/ha yearly and grazed by young cattle over a 2‐year period in the humid tropics of Puerto Rico.Stargrass produced 1,514 kg/ha of beef yearly with daily gains of 0.60 kg per head, compared with 1,062 kg/ha of beef and daily gains of 0.49 kg per head for pangolagrass. Stargrass had a carrying capacity of 7.4 steers (275 kg)/ha compared to 6.5 for pangolagrass. Throughout the year, stargrass had higher dry matter and protein contents (ranging from 11.3 to 19.6%) than pangolagrass.
Phosphorus Utilization by Flax, Wheat, Rape, and Buckwheat from a Band or Pellet‐like Application. I. Reaction Zone Root Proliferation1
Authors: Strong W. M. , Soper R. J. 
Published: July 2010

AbstractTo explain the large variability among crops in their utilization of P from band or pellet‐like applications, the recovery of 32P‐labelled dicalcium phosphate dihydrate (DCPD) from a simulated phosphate fertilizer reaction zone was studied in a pot experiment with four crops, flax (Linum usitatissimum L., cv. Redwood), wheat (Triticum vulgare L., cv. ‘Manitou’), rape (Brassica napus L., ‘Tanka’), and buckwheat (Fagopyrum escutentum Moench). Attention was focused on the portion of the root system which feeds on the applied P. Reaction zone root development was quantified by confining the spread of applied P to a small, easily recoverable portion of the soil mass in the pot. Root systems of the four crops proliferated within this simulated phosphate reaction zone, each to a varying degree. In increasing order of reaction zone root proliferation, the crops ranked as follows: flax, wheat, buckwheat, and rape.The influence of root development within the fertilizer reaction zone on applied P utilization was assessed for these four crops by comparing crop utilization of applied P from two systems each fertilized with a simulated fertilizer reaction zone containing 32P‐labelled DCPD. In one system the reaction zone was positioned at the center of the soil mass within the pot. In the other, a greater opportunity was afforded the root system to develop within the reaction zone by so positioning the reaction zone that the entire root mass passed through it. Recovery of labelled P from these contrasting pot shapes indicated that the proportion of the root system which feeds within the reaction zone as well as the opportunity given it to absorb applied P has direct bearing on crop recovery of band applied phosphatic fertilizer.
Screening of Rice Cultivars for Tolerance to Al‐toxicity in Nutrient Solutions as Compared with a Field Screening Method1
Authors: Howeler R. H. , Cadavid L. F. 
Published: July 2010

AbstractUpland rice (Oryza sativa L.) grown on acid soils may suffer serious yield reductions due to Al‐toxicity. Field experiments showed that many tall traditional cultivars from acid soil areas required only small lime applications, while most of the new semi‐dwarf cultivars required substantial quantities of lime to reach their yield potential. Without or with modest applications of lime, the tall Al‐tolerant cultivars consistently outyielded the Al‐susceptible semi‐dwarf cultivars. Since high lime applications are often prohibitively costly and difficult to incorporate deeply, Al tolerance can be an important characteristic for upland rice cultivars.Large numbers of rice cultivars were screened in the field for AI tolerance at several lime levels. A more rapid nutrient solution screening method for rice seedlings was developed. The relative rootlengths (RRL) of plants grown at 30 and 3 ppm AI was used as an index of AI tolerance. The RRL values of eight cultivars used as standards corresponded to field observations of their relative tolerance to acid soils. Moreover, the RRL values of 240 cultivars were well correlated with grain yields in the field, obtained at a low lime level.
Leaf, Petiole, and Stem Accumulation, and Digestibility in ‘Amclo’ Clover1
Authors: Beaty E. R. , Smith Albert E. , Powell John D. 
Published: July 2010

AbstractThe South has long needed a high yielding legume to complement the perennial grasses of the region. ‘Amclo’ arrowleaf clover (Trifolium vesiculosum Savi) released in 1963 is high yielding and the forage is high in quality, but management required to maintain the high quality in the harvested feed is not known. We wanted to know the dry matter accumulation rate and digestibility during the active growth period. In 1973 and 1974, we measured dry matter accumulation and digestibility of leaves, stems, petioles and flowers of field grown volunteer stands of Amclo clover growing on Orangeburg loamy sand, a silicous thermic typic Paleudult by harvesting a new plot each week from January or February until June. The plant samples were separated into plant parts, dried, ground, and analyzed for in vitro digestible dry matter weekly throughout the experiment.By mid‐March leaflet and petiole production had maximized at 3,500 to 4,000 kg/dm/ha. Stem growth was active during April and by 2 May stem yield was approximately 6,000 kg/ha. During May stem growth slowed and flowering was active. Flower production averaged approximately 2,000 kg/ha. In vitro dry matter digestibility averaged 69% for leaves and 73% for petioles while stem digestibility dropped from 73% in March to 51% in June.Leaf N averaged 5.5% until mid‐April and fell to 3.2% in June. Petiole N averaged approximately 2% throughout the growth period and stem N was high in March but decreased rapidly in late April and May. By 6 June stem N was approximately 1%.Total forage N increased from 59 kg/ha in early February to 232 kg/ha on 11 April and remained constant at that level during May and into June.The arrowleaf clovers are growing in importance for both grazing and harvested feed. Value for each is related to the mix of leaves, petioles, and stems. This research shows the ratio and IVDMD of each over the life of the plant. The arrowleaf clovers are being used for grazing, hay, industrial forage, and silage over a wide range of uses and these data are expected to be widely used in making more effective management time of harvest decisions.
Forage Establishment in Wheat Stubble
Authors: Olsen F. J. , Jones J. H. , Faix J. J. 
Published: July 2010

AbstractThe establishment of forages using wheat (Triticum aestivum L.) as a companion crop has been unreliable in recent years because of competition for light and moisture by vigorous, high‐yielding, modern wheat cultivars. This field study was conducted during 1975–77 to assess the feasibility of establishing forages in late summer in wheat stubble grown on a fine‐silty, mixed, mesic Aquic Hapluadolf soil using different tillage systems and seeding implements. Tillage systems used included conventional, disk, and no‐till. The Allis‐Chaimers No‐Till planter, Brillion seeder, International Harvester grain drill, John Deere Model 1500 Powr‐till drill, and Zip seeder were employed to determine the possibility of obtaining acceptable stands of Ladino clover (Trifolium repens L.), red clover (Trifolium pratense L.), and tall fescue (Festuca arundinacea Schreb.). Forages were successfully established in wheat stubble without tillage using the Allis‐Chalmers No‐Till planter and John Deere Model 1500 Powr‐till drill. Satisfactory forage stands were obtained using the Brillion seeder and International Harvester grain drill in disked wheat residue and a conventionally prepared seedbed. The Zip seeder did not operate satisfactorily in wheat stubble in this study. Planting forages in wheat stubble enhanced winter cover, providing soil protection from erosion.
Salt Tolerance of Australian Channel Millet1
Authors: Shannon M. C. , Wheeler E. L. , Saunders R. M. 
Published: July 2010

AbstractUndomesticated plant species may be a valuable resource for increasing crop diversity and developing crops for use in semiarid and saline areas. Australian channel millet (Echinochloa turnerana (Domin) J. M. Black) is very drought tolerant; however, its salt tolerance has not been tested. In drum culture studies, conducted in the greenhouse, plant height, weight, and seed grain weight were measured as a function of saline stress. Concentrations of Na, Ca, and Cl in leaves and stems increased as soil salinity increased. At salinities above 1.5 S m−1, E. turnerana is as salt tolerant as bermudagrass (Cynodon dactylon L.). The grain yield by E. turnerana was decreased by 50% by 2.4 S m−1 salinity; whereas, previous studies have shown that proportionate grain yield reductions of sorghum [Sorghum bicolor (L.) Moench] and barley (Hordeum vulgare L.) occur at 1.1 and 1.8 S m−1, respectively. E. Turnerana has high salt tolerance as either a grain or forage crop, and as a forage displays superior digestibility. This species could be exploited for future use on marginal lands.
Compensatory Response of Sunflower to Stand Reduction Applied at Different Plant Growth Stages1
Authors: Miller J. F. , Roath W. W. 
Published: July 2010

AbstractDifferential plant populations occurring among plots in yield trials can be critical in evaluating potential worth of sunflower (Helianthus annuus L.) hybrids or breeding lines. The objective of this study was to determine degree of loss in seed yield when stand is reduced at various growth stages of plant development and to identify the nature of plant compensation for stand loss in sunflower.No significant reductions in seed yield occurred when plant populations were reduced 25% from the check (50,000 plants/ha) at the 4, 8, and 16‐leaf growth stages. Compensation was due to significant increases in head diameter. Stand loss of 25% at later growth stages resulted in significant yield loss. Compensation occurred in seed weight as well as head diameter when stands were reduced 50% at early growth stages. Seed yields were reduced 18 to 23%.Sunflower plants were able to significantly compensate even when 75% stand reduction was applied at bud and flowering stages, with seed weight accounting for most recovery in yield. A 38 to 42% and 56 to 58% loss occurred when stands were reduced 75% at the 4 to 16‐leaf and bud to flowering growth stages, respectively. Oil percentages of seeds from plants grown in plots with high stand reductions were reduced 6% and height was decreased 25 cm. Significant negative correlations were noted between oil percentage and height with yield, head diameter, and seed weight at the lowest plant population. Plant population would be critical to control in studies investigating inheritance of plant height or oil percentage of sunflower.
Warm‐season Grass Establishment with Atrazine1
Authors: Martin A. R. , Moomaw R. S. , Vogel K. P. 
Published: July 2010

AbstractWeed competition is a limiting factor in warm‐season grass establishment often delaying the first forage harvest 2 or 3 years. Weed control with herbicides could reduce this competition resulting in more rapid grass establishment. Field experiments were conducted to evaluate the effect of atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] on weed control, warm‐season grass establishment, and forage yield during the seeding and following year.Several warm‐season grass species were spring seeded at locations having distinctly different soils. The soils involved were a Butler silty clay loam (Abruptic Argiaquoll) containing 3.8% organic matter and a pH of 5.2, a Crofton silty clay loam (Typic Ustorthent) containing 2.1% organic matter with a pH of 7.2 and a Nora silty clay loam (Udic Haplustoll) containing 2.8% organic matter and pH 5.8. Atrazine at various rates was applied preemergence shortly after grass seeding and at one site it was atso applied the preceding fall. Weed control, grass establishment, and forage yield were measured the year of seeding and the following year.Uncontrolled weeds during the year of seeding reduced stands and 1st year forage yields of big bluestem (Andropogon gerardi Vitman), indiangrass [Sorghastrum nutans (L.) Nash], sand lovegrass [Eragrostis trichodes (Nutt.) Wood], sideoats grama [Bouteloua curtipendula (Michx.) Torr.], and switchgrass (Panicum virgatum L.). Big bluestem and switchgrass tolerated preemergence atrazine applications of 3.4 kg/ha on the Butler soil. Big bluestem was less tolerant of atrazine than switchgrass on the Crofton soil. Some atrazine tolerance was present in indiangrass but not in sand lovegrass and sideoats grama. Seeding year forage yields of big bluestem and switchgrass were significantly increased by atrazine. Weed control during the seeding year sometimes resulted in higher forage yields the following year. Big bluestem and switchgrass can he readily established and produce substantial forage yields the year of seeding by using atrazine for weed control. This would make these grasses more attractive to farmers and ranchers.
A Field Study of Plant Resistance to Water Flow in Alfalfa1
Authors: Abdul‐Jabbar A. S. , Lugg D. G. , Sammis T. W. , Gay L. W. 
Published: July 2010

AbstractThe objective of this study was to investigate the plant resistance to water flow (Rp) in alfalfa (Medicago sativaL.) under field conditions. Plant resistance was computed using Ohm's law analog from leaf water potential (ψ1), transpiration rate (T), soil resistance (Rs), and soil water potential (ψs). A pressure chamber was used to measure ix hourly throughout the 3 days, 18, 19, and 20 Aug. 1982. Evapotranspiration rate (ET) was measured continuously using the energy balance‐Bowen ratio method, and T was assumed to equal ET because the alfalfa completely covered the soil, thus limiting evaporation from the soil. The leaf area index was 4.3. Soil resistance was computed from root radius and root length density data, and had a value of 698 h, which was much smaller than the calculated value of (Rp). Soil water potential was calculated from soil moisture content data obtained using a neutron probe. Using this approach, Rpwas almost constant throughout the day from 0730 to 1500 h, with an average value of 1.97 × l05h. From 0730 to 1500 h, (Rp) was not significantly correlated (P<0.05) with the water potential gradient (ψ1−ψs) (r=0.08). In addition, & was not significantly correlated with values of T above 0.2 mm/h (r= −0.32). Plant resistance to water flow in alfalfa was similar to reported values for other crops.
Structural Polysaccharides in Forages and Their Degradability
Authors: Hatfield R.D. 
Published: July 2010

AbstractPlant cell walls are organized into complex matrices composed primarily of carbohydrates that represent a potential energy source for ruminants. An overview of the basic structural features of the major groups of polysaccharides that make up forage cell walls, metabolic changes during cell wall development, cell wall component interactions, and some aspects of cell wall degradation are presented. Polysaccharide components that compose the cell wall matrix can be disassociated and fractionated according to similar physio‐chemical properties. Plant structural polysaccharides vary in monosaccharide composition, substitution patterns, and glycosidic linkages between monomers. Chemical fractionation schemes typically separate structural polysaccharides into three major groups. These include pectic polysaccharides rich in galacturonic acid residues, hemicellulosic polysaccharides typically rich in xylose, and the cellulose fraction. Mature walls can be envisioned as a layered matrix with cellulose microfibrils embedded in an amorphous material composed of pectic and hemicellulosic polysaccharides. The amorphous regions of cell walls show the greatest variation during development. Interactions among individual components of the cell wall are key to the formation and structural integrity of the matrix. These include bonding interactions that range from weak hydrogen bonds to covalent cross‐links. During growth of plant cells there is a rearrangement of structural elements within the wall. The matrix undergoes reorganization by disruption of selected intra‐ and intermolecular bonds and de novo synthesis and insertion of new wall polymers. Individual polysaccharides may vary in rates and possibly extent of degradation by rumen microorganisms. These differences are due to the degree of hydrogen bonding of the individual polysaccharides, branching patterns, and associations with other wall constituents.
Crop Production During Conversion from Conventional to Low‐Input Methods
Authors: Liebhardt W. C. , Andrews R. W. , Culik M. N. , Harwood R. R. , Janke R. R. , Radke J. K. , Rieger‐Schwartz S. L. 
Published: July 2010

AbstractA 5‐yr cropping system experiment was initiated in 1981 to study transition from a conventional agricultural system using pesticides and fertilizers to a low‐input system. The site was primarily Comly silt loam (fine‐loamy, mixed, mesic, Typic Fragiudalf) with 12% Berks shaly silt loam (loamy‐skeletal, mixed, mesic, Typic Dystrochrept), and a small area of Duffield silt loam (fine‐loamy, mixed, mesic, Ultic Hapludalf), in Berks County, eastern Pennsylvania. Three 5‐yr rotations were compared. A conventional corn (Zea mays L.)‐soybean [Glycine max (L.) Merr.] rotation (designated “conventional”) was compared to two low‐input rotations which utilized oat (Avena sativa L.), red clover (Trifolium pratense L.) and winter wheat (Triticum aestivum L.), in addition to corn and soybean. One low‐input rotation used cattle manure as a nutrient source and produced forage crops in addition to cash crops (designated “low‐input/livestock”), while the other used legume crops as a nutrient source, and produced a cash crop every year (designated “low‐input/cash grain”). Corn grain yields in the low‐input systems were 75% of conventional in 1981 to 1984, but yields were not significantly different in 1985. Weed competition and insufficient N limited low‐input corn yields during the first 4 yr. Soybean yields in the low‐input systems were equal to or greater than conventional all 5 yr. It is concluded that a favorable transition from input‐intensive cropping to low‐input systems is feasible, but only if crop rotations are used which include crops that demand less N and are competitive with weeds, such as small grain, soybean, or legume hay. Corn should be avoided for the first 3 to 4 yr.