bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localized Dry Spots as Caused by Hydrophobic Sands on Bentgrass Greens
Authors: Tucker K. A. , Karnok K. J. , Radcliffe D. E. , Landry G. , Roncadori R. W. , Tan K. H. 
Published: July 2010

AbstractConstruction of creeping bentgrass (Agrostis palustris Huds.) golf greens with topsoil mixtures that contain 90% or more sand has led to the appearance of irregularly shaped areas of wilted or dead turfgrass known as localized dry spots (LDS). Objectives were to determine by means of a survey the association between management practices and the severity of LDS, and to compare the chemical and physical properties of LDS and adjacent healthy areas (HA) of greens. Turf managers from ten golf courses and the University of Georgia Turfgrass Plots completed a 34‐question survey pertaining to management practices used on their respective greens. Four of the golf courses and the University Turf Plots were selected as sampling sites for soil from both LDS and HA. Soid was analyzed for moisture content, and particle size, as well as hydrophobicity via the water droplet penetration time, and contact angle methods. Soil organic matter, soluble salts, pH, P, K, Ca, Mg, Zn, Mn, B, and NO3, were also determined. In addition, soil from each area was viewed with a scanning electron microscope. Dry spots occurred at all locations surveyed and no correlation was observed between management practices and the severity of LDS. No differences in soil chemical properties were found between LDS and HA, but water droplet penetration time and contact angle were greater in LDS compared to HA. This hydrophobic condition was confined to the top 50 mm of soil in the dry spot samples and coincided with the presence of an organic coating on sand grains that was observed by scanning electron microscopy.
Quantitative Reduction and Inclusion of Plant Tissue Nitrates in Kjeldahl Digestion
Authors: Goyal Sham S. , Hafez Ahmed A. 
Published: July 2010

AbstractThis study was prompted by controversy over the accuracy of the existing predigestion methods to include NO3‐N in Kjeldahl digestion. A system for quantitative reduction of NO−3 to NH+4 using the Zn metal and Cu2+ in 2 M H3PO4 was developed and was used as a predigestion treatment. Using four different acids in a Zn metal and Cu ion system, the efficiency of NO3 reduction was found to be depenndent on the acid type and its concentration. The Cu ions catalyze the Zn‐acid reaction and improved reproducibility compared to treatments with no Cu2+ added. Four milliters 2M H3PO4 containing 40 mg Cu2+ as CuCl2˙2H2O and 0.3 g Zn recovered 100% of the NO−3‐N in plant materials containing as high as 2.51% NO−3–N (200 mg sample). Tissues containing higher levels of NO−3–N may be analyzed using smaller size sample, e.g. 150 mg. The digestion procedure includes acidified H2O2 treatment at low temperature to solubilize unused Zn and partially oxidize plant organic matter to control foaming and frothing. Small digestion tubes (50‐mL) and a digestion block were used for greater efficiency. The method is simple, highly reproducible and convenient.
Sprinkler vs. Flood Irrigation in Traditional Rice Production Regions of Southeast Texas
Authors: McCauley G. N. 
Published: July 2010

AbstractSprinkler irrigation of rice (Oryza sativa L.) could conserve water and lower production costs. Tests were conducted for 3 yr (1982–1984) on a Beaumont clay soil (Entic Pelludert) to evaluate 12 rice cultivars under flood and three levels of sprinkler irrigation. Plant growth (height), plant development (days to heading and harvest), yield, yield components, and quality were monitored. Irrigation treatments were main plots and cultivars were subplots. Irrigation treatments 100, 50, and 25 replaced 100, 50, and 25% of estimated evapotranspiration (ETe). Total water applied was 931 mm (1982), 1171 mm (1983), and 1061 mm (1984) for Treatment 100. These applications exceeded the ETe of flooded rice by 331 to 571 mm. Compared to flood irrigation, sprinkler treatments reduced plant height by 0.09 to 0.28 m. Days to heading varied by cultivar and irrigation treatment while days to harvest was not affected by the irrigation treatments. Milled grain was not influenced by irrigation. Compared to the average yield for flood irrigation, sprinkler irrigation reduced yield over 20% with Treatment 100 and key cultivar yields were reduced 28%. Yield loss from Treatment 100 could not be attributed to weeds, diseases, or water availability. Yield loss was due to reduced florets/panicle and reduced fertile florets. With a yield differential in excess of 20%, sprinkler irrigation does not appear to be a viable alternative to conventional flood irrigation in traditional rice‐growing areas.
Carbohydrate and Lignin Partitioning in Sorghum Stems and Blades
Authors: McBee G. G. , Miller F. R. 
Published: July 2010

AbstractDeclining fossil fuel supplies has stimulated development of alternate energy sources from plant biomass. Sorghum [Sorghum bicolor (L.) Moench] has been recognized as an excellent crop for anaerobic fermentation to methane because of high carbohydrate content of the vegetative biomass. This study was conducted to determine quantities of hemicellulose (HC), cellulose (CL), lignin (LG), and nonstructural carbohydrates (NSC) partitioned between stems and blades of a spectrum of sorghums. Six entries, E35‐1, AT✕ 623 ✕ ‘Rio’ (primarily forage types), Giza‐114 (biomass type), RT✕432, AT✕623 ✕ RT✕432, and AT✕623 ✕ RT✕430 (grain types), were produced on a Ships clay (very‐fine, mixed, thermic Udic Chromustert). Plants were harvested at physiological maturity of the kernels, separated into stem and leaf blade fractions, and analyzed for HC, CL, LG, and NSC. Structural component content ranged from 716 to 516 g kg−1 for stems and 652 to 567 g kg−1 for the blades. Stems contained 12 to 39 g kg−1 more LG than blades across entries. Content of HC in blades exceeded that of stems, whereas CL levels were higher in stems than blades for all entries except E35‐1. The ratio of HC/CL ranged from 0.7 to 0.9 in the stems and 1.1 to 1.3 in the blades. Rind and pith of Giza‐114, AT✕623 ✕ Rio and AT✕623 ✕ RT✕430 contained more structural components in the rind. The quantity of NSC was 74 to 216 g kg−1 higher in the stems than blades for all entries. Sorghum stems may contain large quantities of NSC and structural components, but blades are low in NSC for purposes of digestion or methanogenesis.
Legume Species and Proportion Effects on Symbiotic Dinitrogen Fixation in Legume‐Grass Mixtures
Authors: Mallarino A. P. , Wedin W. F. , Goyenola R. S. , Perdomo C. H. , West C. P. 
Published: July 2010

AbstractOptimal utilization of the N2‐fixation capability of legumes improves forage productivity and quality and reduces the need for N fertilizer. This research assessed N2 fixation in binary mixtures of white clover (Trifolium repens L.) (WC), red clover (Trifolium pratense L.) (RC), or bitdsfoot trefoil (Lotus corniculatus L.) (BT) with tall fescue (Festuca arundinacea Schreb.) (TF) at four legume proportions. Two identical experiments were established in Uruguay, one in 1983 (Exp. 1) and one in 1984 (Exp. 2) that were evaluated for 2 yr. The soil of the area was a fine, montmorillonitic, mesic, Typic Argiudoll. Symbiotically fixed N was estimated by 15N isotope dilution by using TF pure stands as nonfixing reference. The proportion of legume N derived from air (%Ndfa) was larger in winter and spring harvests (82‐95%) than in other harvests, and differences among legumes were minimal. In first harvests after seeding, %Ndfa was 58% for BT and 74% for WC or RC, whereas in summer, WC showed the least %Ndfa. Total fixed‐N yield over 2 yr was greatest for RC‐TF (390 and 330 kg ha−1 for Exp. 1 and Exp. 2) because of both large %Ndfa and legume yield. As legume proportion increased %Ndfa decreased linearly, usually with similar slopes for all legumes. Fixed‐N yield increased linearly as legume proportion increased for RC‐TF and BT‐TF mixtures. For WC‐TF, there were optimal WC proportions between 50 and 70% in seeding years. We conclude that %Ndfa was negatively and linearly related to legume proportion for the three mixtures and that legume‐dominant swards were required to maximize fixed N yields for RC‐TF and BT‐TF but not for WC‐TF. Red clover fixed the greatest amount of N2 under the conditions of this study.
Corn Response to Rye Cover Crop Management and Spring Tillage Systems
Authors: Raimbault B. A. , Vyn T. J. , Tollenaar M. 
Published: July 2010

AbstractThe use of a winter rye (Secale cereale L.) corn (Zea mays L.) doable cropping sequence in combination with appropriate tillage practices could increase biomass production and reduce soil erosion potential in southern Ontario. A 3‐yr study (1982–1984) was conducted at two locations to determine the potential of this sequence for double cropping, and to evaluate spring tillage systems and management of the rye residue on subsequent productivity of corn. Winter rye was planted in early October after corn silage harvest, and either chemically killed or harvested as silage in the spring before corn planting. Rye treatments consisted of no rye, rye harvested in the spring and rye residue left on the plots. Spring cultivation treatments were no‐till, tandem discing, and mold board plowing followed by secondary tillage. The use of a winter rye cover crop delayed corn development and reduced corn biomass yield by 11% at the Elora location and by 17% at the Woodstock location. The adverse effect of the rye crop was more pronounced under no‐till than where the soil was tilled. Removal or retention of the rye residue had no consistent effect on the subsequent corn crop. An allelopathic effect resulting from the rye crop may be one plausible explanation for the reduction in corn yield. Total biomass yield (rye + corn) was increased relative to corn alone, if the soil was cultivated. Therefore, a winter rye‐corn sequence may still be of interest, despite a reduction in corn yield, especially if advantages such as total biomass production and the potential for decreased soil erosion during fall and winter are considered.
Salinity Effects on Vegetative Growth, Seed Yield, and Fatty Acid Composition of Crambe
Authors: Francois L. E. , Kleiman R. 
Published: July 2010

AbstractAgronomic development and crop diversification may promote an increased acreage of crambe (Crambe abyssinica Hochst. ex R.E. Fries) in the USA. To determine whether crambe can be grown successfully on saline soils, a 2‐yr‐field‐plot study was conducted. Five cultivars and three germplasm releases were grown with four salinity treatments imposed on a Pachappa fine sandy loam (mixed, thermic, Mollic Haploxeralf). Electrical conductivities of the irrigation waters, containing NaCl and CaCl2 (1:1 by weight), were 0.9, 3.7, 5.4, and 7.9 dS m−1. Seed yield, vegetative growth, and fatty acid composition of the seed oil were measured. Seed yield showed no statistical reduction over the salinity range tested each harvest year. Differences between harvest years were statistically significant. Analysis of the combined 2‐yr data showed a 6.5% reduction of seed yield for each unit increase in soil salinity above 2.0 dS m−1. These results place crambe in the moderately sensitive salt tolerance category. Individual seed weight was significantly reduced by salinity for six of the eight cultivars or germplasms studied. Increased salinity did not significantly affect the erucic acid component of the seed oil, but did significantly reduce the oleic, linolenic, and eicosenoic components.
Significance of Ancient Agricultural Soils for Long‐Term Agronomic Studies and Sustainable Agriculture Research
Authors: Sandor J. A. , Eash N. S. 
Published: July 2010

AbstractFor agriculture to be sustainable, it must maintain productivity and environmental conservation for many generations. Long‐term field studies are essential to the development of sustainable agricultural systems because they are a primary source of scientific knowledge about agronomic conditions during long periods of farming. In addition to knowledge generated by monitoring fields during the past century, there is also a need for information on a longer time scale. Ancient agricultural sites are potential sources of information about agronomic conditions after centuries to millennia of use. Although only the end results of farming can be directly observed at these sites, partial reconstruction of the agricultural history is possible. Studies in Peru and New Mexico, in which ancient agricultural soils were evaluated relative to uncultivated soils, are presented here to illustrate the potential of ancient agricultural sites to extend the time perspective of long‐term research on soil tilth, fertility, and conservation. Studies of ancient agricultural sites can also contribute to ideas about land stewardship and agricultural sustainability.
Support for Long‐Term Agricultural Research
Authors: Army Thomas J. , Kemper* W. Doral 
Published: July 2010

AbstractAgricultural research, like most present day science generally consists of short‐term studies. A sustainable agriculture, however, requires a long‐term field and laboratory approach to determine the, complex interactions of soils, plants, animals, climate, and management. Short‐term funding and pressures to publish are the major, factors discouraging the initiation of needed long term crop and animal research projects.
Soybean Cultivars' Response to Flood Irrigation of Clay Soil
Authors: Heatherly Larry G. , Pringle H. C. 
Published: July 2010

AbstractSurface irrigation is widely used to increase seed yield of soybean [Glycine max (L.) Merr.] grown on clayey soils of the southern Mississippi River alluvial plain. A field study was conducted on Sharkey clay (Vertic Haplaquept, very‐fine, montmorillonitic, thermic) in 3 yr to measure the effect of flood irrigation of varying duration on yield and yield components of soybean. Treatments were (Treatment 0) nonirrigated; (Treatment I) 24 h to flood (soil submerged 24 h after onset of irrigation) and then drained; (Treatment 2) 24 h to flood plus 24‐h moving water flood, then drained; (Treatment 3) 24 h to flood plus 48‐h moving water flood, then drained, (Treatment 4) soil submerged with static water for 24 h, then drained; and (Treatment 5) soil submerged within 2 h of onset of irrigation, and then drained. All irrigation treatments commenced at first bloom and repeated whenever soil water potential of a treatment dropped below −70 kPa at 30cm depth. ‘Sharkey’ soybean was more responsive than was ‘Centennial’, but all irrigation treatments resulted in significant yield increases of both cultivars in years when rainfall was deficient during reproductive development. Treatment 3 flooding resulted in significantly lower seed yield than did Treatment 1 flooding, while Treatments 1 and 2 floodings achieved similar yield increases. In a rainy year (1988), Treatment 3 average yield was lower than yields from all other treatments. This indicates that even relatively short periods of flooding can be detrimental to soybean if complemented with untimely rainfall. Standing water for 24 h (Treatment 4) produced yield increases that equalled or exceeded those of all the moving water treatments. These results showed that flood inundation of less than 48 h will result in the consistently largest significant yield increase for soybean, and that soybean genotypes differ in their response to flood irrigation.
A Nitrogen‐Phosphorus‐Potassium Model For Forage Yield of Bermudagrass
Authors: Overman A. R. , Dagan A. , Martin F. G. , Wilkinson S. R. 
Published: July 2010

AbstractA logistic equation was used to relate annual dry matter yield of Coastal bermudagrass [Cynodon dactylon (L.) Pers.] to applied N, P, and K. Yield data from a 4 ✕ 4 ✕ 4 (N ✕ P ✕ K) factorial experiment were analyzed. The second order Newton‐Raphson procedure for nonlinear regression was used to estimate the seven parameters of the model. A correlation coefficient of 0.9884 was obtained with the model for the 64 data points. A response surface for yield as related to N and K at P = 100 kg ha−1 was drawn from the model. Isoquants (constant yield) were drawn for annual yield of 10 Mg ha−1. A residuals diagram showed no trends, lending further validity to the model. These results have application to agricultural production and environmental quality.
Research Plot Planter for Furrow Irrigated Cropping Systems
Authors: Bjornestad Lyle R. , Lauer Joseph G. 
Published: July 2010

AbstractCommercially available research plot planters are primarily designed for dryland and/or sprinkler irrigation systems. Research plot establishment in cropping systems involving furrow irrigation requires a planter with an adjustable drive system for diverse furrow spacings. Tool bars should have no interfering support brackets. These features will provide the flexibility needed for a wide range of row and furrow spacings. The planter was designed and constructed for establishing research plots in furrow‐irrigated cropping systems. The planter drive wheels provide flexibility for furrow spacings ranging from 0.25 to 2.2 m. Two tool bars with no interfering support brackets allow numerous row spacing arrangements for seed and furrow openers. The planter can be adjusted quickly (approximately 1h) for different furrow systems, and thus, used for research and/or extension demonstration purposes both on‐ and off‐station.
Cutting Interval and Irrigation Timing in Alfalfa: Yellow Foxtail Invasion and Economic Analysis
Authors: Norris Robert F. , Ayres Debra 
Published: July 2010

AbstractYellow foxtail (Setaria glauca (L.) Beauv.) is the most serious summer annual weed in alfalfa (Medicago sativa L.) in the Central Valley of California. The experiment evaluated the importance of cutting interval and timing of irrigation on invasion of the weed into established alfalfa. The crop was cut on a 25‐, 31‐ or 37‐d interval. Irrigation was applied on the same day as cutting or after a delay of 7 or 14 d. A factorial treatment combination was used in a randomized complete block fielld design. The experiment was continued for 3 yr. Alfalfa yield increased with increased length of cutting interval but was not affected by irrigation regime. Yellow foxtail invasion was minimal at the 37‐d cutting interval, was intermediate at the 31‐d interval, and reached 20 to 30% of late‐season harvests at the 25‐d cutting interval. Delaying irrigation following cutting reduced yellow foxtail invasion 2 yr out of three; this effect was largest for hay cut on the 31‐d interval. Cash‐flow economic analyses showed that cutting at a 25‐d interval resulted in the lowest net return due to low overall yield and substantial yellow foxtail invasion late in the season. Hay cut at the 31‐d cutting interval would provide the highest net return. Reduced alfalfa quality compromised the return for the 37‐d cutting interval. Yellow foxtail can be controlled in alfalfa by manipulation of cutting interval.
Border Effects on Nitrogen‐15 Fertilized Winter Wheat Microplots Grown in the Great Plains
Authors: Follett R. F. , Porter L. K. , Halvorson A. D. 
Published: July 2010

AbstractField experiments requiring 15N enriched fertilizer are costly, thus microplot techniques are generally used. Placing physical barriers around microplots to contain the 15N may introduce artifacts that affect N recovery by crops, limit types and numbers of measurements, and cause other restrictions. The purpose of this experiment was to determine minimum microplot size (without the use of barriers) for accurately measuring enriched 15N uptake into a winter wheat crop, while using normal field cultural practices. Winter wheat (Triticum aestivum L.) was seeded into KNO3 fertilized (56 and 112 kg N ha−1) plots (4.57 m by 3.05 m) on a Platner silt loam soil (fine montmorillonitic mesic Aridic Paleustol). Within each larger plot, four microplots (2.29 m by 1.83 m) were fertilized with 10 atom % 15N enriched KNO3 at the same rate as for main plots. Nitrogen‐rate treatments were replicated four times in a randomized block design. Above ground plant material was harvested (0.3 m of row) from six adjacent rows at flowering (Feeke's scale = 10.5). Three rows were harvested from inside (15N enriched KNO3 added) and three from outside (15N enriched KNO3 not added) of the microplots. Plant uptake of total N into plant tops was not significantly different across any of the six harvested rows. Dry matter yields and total‐N uptake were significantly larger for the 112 than for the 56 kg N ha−1 fertilizer rate, as were the 15N uptake and atom 15N % values in plant material within the microplots. In rows adjacent to microplot borders, concentrations of 15N in plant material changed rapidly; but there were no differences beyond 0.46 m inside or outside the microplots. These results indicate that minimum microplot size for studies with fall‐applied 15N on winter wheat grown in the Great Plains is 1.5 by 1.5 m.
Calcium Stimulation of Ammonium Absorption in Onion
Authors: Fenn L B. , Taylor R. M. , Binzel M. L. , Burks C. M. 
Published: July 2010

AbstractThe inefficiency of N use in soils has been studied widely, producing varied suggestions for increased effectiveness. The object of this research was to examine the use of Ca2+ as a means to increase NH+4 absorption, using onion (Allium cepa L.) as a test crop. Ammonium absorption in the presence of variable Ca2+ concentrations was measured in short‐term greenhouse studies as well as longterm greenhouse studies and field‐production trials. The greenhouse 15NH+4 absorption study was conducted in 4‐L pots containing 3.5 kg of calcareous Gila sandy loam (coarse‐loamy, mixed, calcareous, thermic Typic Torrifluvents). The long‐term growth study was conducted in calcareous quartz sand. Irrigation solutions consisted of half‐strength nutrient solutions (5 mol m−3 in NH+4) with Ca2+:NH+4 molar proportions of 0, 0.25, 0.50, 1.00, and 2.00. The 15NH+4 absorption study was conducted during a 30‐h period on 60‐d onion. The long‐term growth experiment received the same nutrient solutions until mature onion bulbs were produced (about 5 cm in diameter). A 2‐yr field production trial used single rows on 1‐m wide beds. The soil was a calcareous Saneli silty clay loam [clayey over sandy or sandy‐skeletal, montmorillonitic (calcareous), thermic Vertic Torrifluvent]. In 15NH+4 studies, NH+4 absorption increased with added Ca by as much as 189% in onion bulbs and by 67% in onion tops relative to absorption with no Ca added. These maximum increases were in association with solution Ca2+:NH+4 molar proportions (MP) of 0.5 in onion bulbs and 1.0 in onion tops. Total plant dry weights with Ca added increased as much as 100% in bulbs and 25% in tops in 30‐h 15NH+4 absorption tests over the 0 Ca2+ controls. In greenhouse growth tests, vegetative matter increased as much as 40% with increasing Ca2+ concentrations at constant NH+4 levels compared to the 0 Ca2+ control. This translated to increased total N absorption. In 2 yr of field testing with a MP of 0.25, mature bulbs from both years increased 64% over yields with urea alone. Thus the addition of Ca2+ with urea produced significantly improved plant N‐use efficiencies (greater plant yield at the same level of N application). These results were suggested from both the short‐term greenhouse 15NH+4 absorption experiment and from the long‐term greenhouse growth trial.