bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Soil Compaction on Three Turfgrass Species1
Authors: Carrow R. N. 
Published: July 2010

AbstractWear and soil compaction from foot and vehicular traffic are major stresses on recreational turfgrass areas. Few investigations have been conducted on turf where only soil compaction stress was applied. In this field study the influence of soil compaction on morphological and physiological aspects of three turfgrass species was investigated. The cool season turfgrass species (Lolium perenne L. ‘Pennfine’; Poa pratensis L. ‘Baron’; Festuca arundinacea Schreb. ‘Kenutcky 31’) were subjected to three compaction treatments with a smooth, power roller: 1) O× — none except routine mowing, 2) 12× — 12 times a week for 8 weeks, 3) 24× — 24 times a week for 8 weeks. A fine, montmorillonitic mesic Aquic Arquidoll soil was used.Visual quality, percent turf cover, and total nonstructural carbohydrate (TNC) declined for all species as compaction stress increased. Eight months after compaction ceased, tall fescue and Kentucky bluegrass still exhibited reduced visual quality and percent cover.Shoot density, verdure, and root growth also were affected by compaction, with response differing by species. Increased compaction reduced verdure, shoot density, and root growth of Kentucky bluegrass; decreased verdure for tall fescue; but perennial ryegrass exhibited no adverse effects except some reduction in root weight at the 12× treatment.Compaction tolerance differences among species were determined using the growth parameters measured. With aeration porosity at −0.10 bar water content and bulk density as measures of soil compaction, visual quality rating and percent turf cover gave the best compaction tolerance differentials among species. Species tolerance to compaction, when based on those factors, was perennial ryegrass = Kentucky bluegrass > tall fescue.
Sulfur Diagnostic Criteria as Affected by Age and Defoliation of Subclover
Authors: Jones M. B. , Ruckman J. E. , Williams W. A. , Koenigs R. L. 
Published: July 2010

AbstractSulfur deficiencies are widespread in California annual grasslands and in other areas of the world where subclover (Trifolium subterraneum L.) is an important legume. Intensive grazing is often practiced where subclover is grown. Therefore, to determine the need for S fertilization it is important to know how defoliation and plant age influence the diagnostic tissue tests used to assay subclover S status.Subclover was grown on S−deficient soil (Josephine, fine−loamy, mixed mesic, Typic Haplozerults) with six levels of applied S and four clipping treatments in a greenhouse. Four criteria for assaying S status were used: total S, sulfate S, sulfate S/total S ratio, and N/S ratio in the three youngest fully expanded leaves required to give 90% of maximum yield (critical levels based on Mitscherlich functions).The critical levels of sulfate S/total S and N/S ratios were the most stable over plant age and clipping frequency. Both assays accounted for about three−quarters of the variation on the average.The critical levels of total S and sulfate S although associated with over 90% of the variation were not stable individually, decreasing from 0.20 to 0.08% S and from 220 to 140 pprn sulfate S at 60 and 133 days from planting, respectively. Clipping frequency caused considerable variation in the critical levels for total S and sulfate S assays, making them more difficult to interpret than the sulfate S/total S and N/S ratio assays.It was concluded that the sulfate S/total S ratio has some advantages over the other assays, such as stability through the growing season, being little affected by defoliation, and resulting from a single analytical regime.
A New Look at Row and Broadcast Phosphate Recommendations for Winter Wheat1
Authors: Peterson G. A. , Sander D. H. , Grabouski P. H. , Hooker M. L. 
Published: July 2010

AbstractPhosphate fertilizer recommendations for winter wheat have traditionally been in terms of doubling the row applied P rate if broadcast application is to be used. A literature search failed to locate a significant amount of supportive data for this practice.The experiments reported here were conducted to determine if there is a consistent relationship between broadcast and row applied P rates for winter wheat and if so, what that relationship is.Six field experiments were conducted over a 2 year period on soils of, the Typic Argiustoll subgroup. Treatments were five rates of 0‐46‐0 (0, 11, 22, 34, 45 kg P/ha) applied as either preplant broadcast or drilled with the seed.All experiments were on soils that responded positively to P fertilization. Results contradicted the concept of a 2:1 ratio of broadcast to row P application as standard practice. The relative effectiveness of row and broadcast methods changed with changing soil tat P levels. Low soil test locations exhibited an effective ratio of about 3:1 while medium soils tests had ratios of 1:1.
Ammonium‐N and Nitrate‐N Effects on the Growth and Mineral Compositions of Triticale, Wheat, and Rye1
Authors: Gashaw L. , Mugwira L. M. 
Published: July 2010

AbstractAbsorption and utilization of N has been shown to be affected by the N form supplied and cultivar used. The relative absorption and utilization of NH4+−N and NO3−−N by triticale (X Triticosecale, Wittmack), wheat (Triticum aestivum L.), and rye (Secale cereale L.) have not been determined. This study was conducted to determine the growth and mineral composition of triticale 6TA 131, ‘Arthur’ wheat, and ‘Abruzzi’ rye grown in nutrient solutions containing different NH4+−N/N03−−N ratios in a growth chamber. The NH4+−N/NO3−−N ratios were 0/100, 25/75, 50/50, 75/25, and 100/0. Solutions were sampled every 10 days during a 30‐day plant growth period. Triticale and rye more preferentially absorbed N03−−N over NH4+−N than wheat which sometimes (50/50) absorbed more NO3 than NH4. All species produced higher dry matter with the combinations of 25/75, 50/50, and 75‐25 NH4+−N/NO3−−N ratios than with either N source alone. There were increases in the uptake of N, P, and Fe when NH4+−N/NO3−−N ratio was increased in the mixture whereas NO3−−N increased the uptake of Mg, Ca, Mn, and NO3−−N. These results suggested that the triticale inherited its absorption efficiency of NO3− from rye.
Mechanical Impedance Effects on Oxygen Uptake and Porosity of Drybean Roots1
Authors: Schumacher T. E. , Smucker A. J. M. 
Published: July 2010

AbstractLow oxygen concentrations and mechanical impedance are two components of soil compaction often implicated in the reduction of crop yields. The relative importance of these two stresses to the root system has not been thoroughly assessed. A system was developed to study the effect of mechanical impedance on root respiration and morphology. Oxygen uptake, by intact plant root systems subjected to three levels of mechanical impedance, was determined polarographically by measuring the oxygen concentration of nutrient solutions before and after flowing through a root media of 1 mm, 3 mm, or no glass beads. Oxygen uptake rates by drybean (Phaseolus vulgaris L.) roots were independent of solution flow rates ≥ 6.0 ml/min‐1 when inlet pO2 was 0.21 atm. Mechanical impedance reduced dry weight, fresh weight, volume, and length of roots after 8 days of treatment. Dry matter percentage of mechanically impeded roots was greater than the control. Roots subjected to mechanical impedance were deformed, branched more frequently, less porous, and consumed more oxygen per unit fresh weight. It is suggested that a greater oxygen supply may be required at the root surface to prevent anoxia in mechanically impeded roots.
Allelopathic Effects of Tall Fescue Genotypes1
Authors: Peters E. J. , Mohammed Zam A. H. B. 
Published: July 2010

AbstractTall fescue (Festuca arundinacea Schreb.) has been shown to have allelopathic effects on some species. Some tall fescue genotypes growing in a breeding nursery had large crabgrass [Digitaria sanguinalis (L.) Scop.] infestations while other genotypes had none. The difference in infestations did not appear to be due to competition; therefore, the possibilities of allelopathic effects were investigated. The surface 2.5 cm of soil in which the various tall fescue genotypes were growing was placed in pots in the greenhouse. The crabgrass germination in the greenhouse varied with genotypes in a manner similar to what had been observed in the field. Genotypes were evaluated for allelopathic effects by germinating seeds of birdsfoot trefoil (Lotus corniculatus L.) and medium red clover (Trifolium pratense L.) in petri dishes containing extracts made by soaking 10 g of tall fescue leaves in 100 ml of water for 24 hours. After 10 days, germination of the legume seeds was significantly inhibited by fescue extracts as compared with distilled water. After 14 days, one tall fescue genotypes had significantly less germination of birdsfoot trefoil seed than did three other genotypes, while one genotype had significantly less germination of red clover seed than did one other genotype.Birdsfoot trefoil and red clover seedlings were grown in half‐strength Hoagland's solution containing extracts of three tall fescue genotypes made by soaking 3, 5, and 10 g of tall fescue tissue for 24 hours in distilled water. Roots of birdsfoot trefoil were significantly inhibited by the 10‐g concentration as compared with the 3‐g concentration in two out of three genotypes. The 10 gm concentration of one genotype significantly inhibited shoot growth of birdsfoot trefoil as compared with the 3‐ and 5‐g concentrations. Shoot and root growth of red clover were significantly inhibited by all extracts of tall fescue genotypes. In extracts of two out of three genotypes, the 10‐g concentration significantly reduced the top growth of red clover. Soils on which three fescue genotypes had been grown were incubated in the greenhouse for 0, 1, and 2 weeks and birdsfoot trefoil seedlings were planted into them and in soil that was not exposed to tall fescue. Root and shoot growth of birdsfoot trefoil seedlings was significantly inhibited when grown in soils in which fescue genotypes had been grown, but incubation periods of the soil had no effects. In soil from one genotype, root and shoot growth of red clover were significantly inhibited when unincubated and inhibition decreased when the soil had been incubated for 2 weeks. In soil from another genotype, root and shoot growth of red clover were significantly inhibited in all incubated soils as compared with the check soil. In soil from the third genotype, root and shoot growth of red clover were inhibited at all incubation periods, but inhibition of shoot growth was greater in soil incubated for 2 weeks as compared with 0 weeks.
Soil and Management Factors Correlated With Soybean Yields in Southeastern U.S. Coastal Plain1
Authors: Reich R. C. , Kamprath E. J. , Nelson L. A. 
Published: July 2010

AbstractA field survey of 220 soybean (Glycine max (L.) Merr.) plots was conducted over a 2‐year period on mineral soils in 12 major soybean producing countries in the Coastal Plain of North Carolina. The objectives of this investigation were to study the effects of certain soil and management factors in soybean production and to develop statistical models for explaining variations in soybean grain yields.Multiple regression and correlation statistical techniques were used to analyze the data. Many factors were highly intercorrelated reflecting the very complex nature of the crop‐soil system. No one factor was found to explain a large proportion of the variation in soybean production but multiple regression models were developed for both years which accounted for 71 to 86% of the variation in yield. Extractable Ca and Al saturation, which reflected past liming practices, were soil chemical properties correlated with grain yield. Physical properties related to available water were also correlated with yield. Management factors such as trips across the field before planting, planting date, crop preceding soybeans, and number of years since liming also influenced soybean yields. Multiple regression analysis indicated that soil pH and number of trips across the field were two important factors affecting yield each year.
Growth Response of Alfalfa to Duration of Soil Flooding and to Temperature
Authors: Thompson Todd E. , Fick Gary W. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) is very sensitive to excessive soil water, yet few studies have been done under controlled conditions to quantify the extent of this sensitivity. The objective of these studies was to investigate the effect of wet soil conditions on alfalfa production. The growth of roots and tops was determined in a factorial greenhouse and growth chamber experiment with treatments for duration of flooding and temperature. Five‐week‐old alfalfa plants, potted in pasteurized soil, were flooded to the soil surface for 4, 8, 12, 16, and 20 days at temperatures of 16, 21, and 27 C, and for 3, 6, 9, and 12 days at 32 C. Root and top dry weights (DW) of flooded and control plants were measured upon draining. Three weeks after draining, the plants were cut to a 2.5 cm stubble and top DW was measured. After 2 subsequent weeks of regrowth, top and root DW's were again measured.Results demonstrated that root growth stopped during flooding. As measured over the 3 weeks following drainage, the rate of top growth of plants was reduced by 50% with 8 days of flooding at 16 C, 4 days at 21 C, 3 days at 27 C, and 2 days at 32 C. No net top growth occurred during the 3 weeks following drainage in plants flooded for over 14 days at 16 C, 10 days at 21 C, 8 days at 27 C, and 6 days at 32 C. In most cases, the negative response to flooding occurred before the disease Phytophthora megasperma Drechs. is thought to have been able to have an influence. This argues for a physiological as opposed to a pathological basis for the injury.
Foliar Fertilization of Rice After Midseason1
Authors: Thom W. O. , Miller T. C. , Bowman D. H. 
Published: July 2010

AbstractFoliar fertilization of rice (Oryza saliva L.) with solutions containing N, NPK, and NPKS during reproduction promises to increase yields and affect grain composition. These foliar applications could avoid N depletion as soil N is the major source for late season uptake. To test this hypothesis field experiments were conducted for 3 years with solutions applied at and/or after panicle initiation (2‐mm panicle) in different proportions, and at different rates and times. Applications of N (157 kg/ha) on the soil prior to flooding (preflood) increased yields, ranging from 771 to 2,370 kg/ha, over the no N check but did not affect composition of brown rice. Increases (0.13 to 0.75%) in N concentration of brown rice were associated with foliar applied N of 50 kg/ha or greater, with or without P+K+S at mid‐boot (12‐ to 15‐cm panicle internodes) stage. Split application (panicle initiation and mid‐boot) increased N concentration more than when the total amount of nutrients were applied in one application (panicle initiation). The first or early applications (mid‐boot — 1976; panicle initiation — 1977 and 1978) were effective in increasing yields and the later applications (post flower — 1976; mid‐boot — 1977 and 1978) were more effective at increasing N concentration in brown rice. Differences in P, K, and Zn in brown rice were not related to timing or amount of foliar nutrients applied. Calcium and Mg in brown rice were unaffected.The results indicate that foliar fertilization of rice with solutions high in N at or after panicle initiation can increase yields. A split application can increase yields and N concentration in brown rice.
Effects of Light Intensity on Growth of Some Tropical Forage Species. I. Interaction of Light Intensity and Nitrogen Fertilization on Six Forage Grasses1
Authors: Eriksen F. I. , Whitney A. S. 
Published: July 2010

AbstractIn order to determine the response of some tropical grass species to low light situations such as under plantation crops, seasonal cloud cover, etc., six tropical forage grasses were evaluated over a 20 month period on an Oxic Haplustoll in Hawaii (100 m above sea level) under four light regimes (100, 70, 45, and 27% daylight using polypropylene netting) in the field.The forage grasses evaluated were: Brachiaria brizantha, B. miliifirmis, Digitaria decumbent, Panicum maximum, Pennisetum clandestinum, and P. purpureum. Dry matter yields of N‐fertilized (365 kg N ha−1 yr−1) grasses were highest at 100 and 70% daylight (16 to 40 metric tons of dry matter (DM) ha−1 yr−1), with P. maximum and P. purpureum having highest yields. Under 27% daylight, yields were 8 to 15 tons, with P. maximum, B. brizantha, and B. miliiformis having highest yields. When no N was added maximum yields in tons ha−1 yr−1 were B. miliiformis, 9.2 at 27% daylight; D. decumbens, P. maximum, and B. brizantha, 13.5 to 15.0 at 45% daylight; and P. clandestinum, 9.2 at 70% daylight. P. purpureum without N yielded 30 tons at full daylight, apparently because its very extensive root system invaded adjacent N‐fertilized plots. Percentage of DM in the forage decreased with shading and N fertilization. Percent N increased with decreasing light intensity (from 1.0 to 1.6% hi the minus‐N and from 1.2 to 1.9% hi the plus‐N treatments). Slight acetylene reduction activity was found in soil cores beneath all species, except B. brizantha, indicating that the plants were almost entirely dependent on soil and fertilizer N for growth. Sward height increased significantly with decreasing light intensity and N fertilization. Concentrations of P, K, Ca, Mg, S, Cu, and Zn tended to be higher in shaded forage, higher in N‐fertilized forage (except for P and Zn), and generally higher during the cool season.Thus under N‐deficient conditions, most yield and forage quality parameters were enhanced under moderate shade. Conversely, the tropical grasses studied generally responded to N fertilization only under conditions of moderate to high solar radiation.Root weight data and observations on the rate of recovery after clipping indicate the shaded pastures would require careful management to avoid excessive depletion of root reserves, either by lenient grazing to maintain high leaf areas or by allowing an extended recovery period.
Tall Fescue and Smooth Bromegrass. II. Effects of Nitrogen Fertilization and Irrigation Regimes on Quality1
Authors: Eck H. V. , Wilson G. C. , Martinez Tito 
Published: July 2010

AbstractBoth quantity and quality must be considered in selecting forages for livestock. This study was conducted to determine effects of N and irrigation treatments on the quality of tall fescue (Festuca arundinacea Schreb.) and smooth bromegrass (Bromus inermis Leyss.) forage in the Southern High Plains. ‘Fawn’ tall fescue and ‘Southland’ smooth bromegrass were grown on Pullman clay loam (fine, mixed thermic, Torrertic Paleustoll) under N rates of 0, 168, 336, 504, and 672 kg ha‐1 year‐1 on three water regimes: W‐l, a moderate (about 50‐cm) and W‐2, an adequate (about 100‐cm) irrigation water level, both distributed for season‐long production, and W‐3, a moderate (about 60‐cm) irrigation level distributed for cool‐season forage production. Forage was harvested and analyzed for N, P, K, Ca, Mg, NO3‐ and in vitro dry matter disappearance (IVDMD). Nitrogen fertilization increased N, K, and NO3‐‐N in both forages. The increased K levels increased the K/(Ca + Mg) ratios. Less marked effects of N included slight increases in IVDMD in both grasses, increases in Ca and Mg, and decreases in P in tall fescue but not in smooth bromegrass forage. The total N and NO3‐‐N were lower and the Ca and Mg were higher in forage from W‐2 than in that from W‐l and W‐3. With N rates through 336 kg/ha, NO3‐‐N remained below the 2,000‐ppm level considered harmful to livestock. Forage P and IVDMD were not affected by differences in irrigation. Although smooth bromegrass was superior to tall fescue in N, K, and Ca concentrations and in IVDMD, N fertilization at levels high enough to produce satisfactory yields increased the K/(Ca + Mg) ratios to levels considered critical for induction of grass tetany. With pure stands of smooth bromegrass, supplemental feeding of Mg would be necessary. Tall fescue contained more Mg than did smooth bromegrass, and its K/(Ca + Mg) ratios were favorable. Without P fertilization, feeding supplemental P would be necessary with both forages. Surface‐applied feedlot waste, at N rates equivalent to those applied as NH4NO3, was less than one‐half as efficient as NH4NO3 in increasing N to forage, but it increased P to levels satisfactory for nutrition of mature cows. Both irrigation adequacy and grass species must be considered in fertilizing for maximum production of high quality forage.
Interactions between Forage Sorghum Cultivars and Defoliation Managements1
Authors: Creel Rodney J. , Fribourg Henry A. 
Published: July 2010

AbstractYield and plant constituent responses of forage sorghum (Sorghum bicolor (L.) Moench) cultivars have usually been compared in uniform defoliation management tests. However, the influence of time of harvest and stubble height on differential response of cultivars needs more precise definition. The extent of cultivar × management interaction was studied for ‘Sweet Sioux III’3 (a leafy high‐producing cultivar similar to many others available), ‘FS‐531’ (a silage‐forage cultivar) and ‘Super‐Chowmaker 235’ (several weeks later in maturity than most other forage sorghum cultivars) for 2 years. The soil was a Sequatchie sandy loam (fine‐loamy, siliceous, thermic Humic Hapludults). Stubble height and defoliation managements designed to simulate grazing, greenchop, hay or silage harvests, in various combinations, were used with each cultivar. Chowmaker plants yielded more, had the same or higher N percent, and the same in vitro dry matter digestibility (IVDMD) when cut to a 15‐cm than when cut to an 8‐cm stubble. Sweet Sioux plants yielded more when cut back to 8 cm than to 15 cm, but their N percent and IVDMD were not affected by stubble height. Cutting when forage reached 50 cm previous to the boot (B) or early bloom (EB) cuts delayed subsequent development, and hence harvest, of FS‐531. The other two cultivars reached the B or EB stages at the same time, regardless of whether that harvest was preceded by a prior harvest or not, but the B or EB stages occurred at shorter heights if preceded by a harvest. Harvesting when forage reached 90 cm before the B or EB cut delayed harvest for all cultivars, probably because all regrowth had to originate from axillary meristems. The delay in B or EB harvests may be beneficial in situations where dry matter production later in the season is more desirable. The results suggested that, if the three different cultivars used here had been entered in a yield trial where all entries were managed uniformly, the information on the potential performance of these forage sorghum cultivars could have been misleading. Harvests at early stages of growth would have penalized Super‐Chowmaker 235 in comparison to Sweet Sioux III, and the reverse would have occurred if later stages of growth had been used to determine harvest time.