bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation Use Efficiency among Cotton Cultivars
Authors: Rosenthal W. D. , Gerik T. J. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) cultivars have diverse growth rates and fruiting characteristics that may be due to differences in radiation use efficiency. Potential growth rates were measured to see if differences could be attributed to radiation use efficiency or canopy light transmission coefficients. An irrigated field study was conducted at the Blackland Research Center using three diverse cotton cultivars; Acala SJ‐2, Deltapine 5O, and Tamcot CD3H. Plant densities ranged from 10 to 14 plants m−2. Transmitted, incoming, and reflected photosynthetically active radiation and leaf area index were measured weekly from 3 wk after emergence to boll opening. Dry matter accumulation and leaf area index were significantly different among cultivars both years. Light transmission coefficients were not different, but cultivars differed in radiation use efficiency through the reproductive period. Values for radiation use efficiency ranged from 1.5 g MJ−1 photosynthetically active radiation for Acala to 1.3 g MJ−1 for Tamcot. Values were not significantly different during the vegetative period. These differences during the reproductive period are likely due to differences in boll number and photosynthetic efficiency among cultivars. Tamcot had 50 to 100% more bolls than Acala both years. These results suggest that crop models should account for these cultivar differences in radiation use efficiency.
Root Hair Occurrence anld Variation with Environment
Authors: Meisner C. A. , Karnok K. J. 
Published: July 2010

AbstractEarly literature on peanut [Arachis hypogcrea (L.)] indicates the existence of two forms of root hairs: (i) a rosette form of root hair (4 mm long) occurring; radially where a lateral root initiates from a primary root, and (ii) shorter (0.30 mm), more profuse root hairs occurring along root lengths usually behind the root tip. Since little is known about the factors that influence peanut root hair formation, the purpose of this study was to quantify root hair formation under various soils and water stress conditions. Separate rhizotron, field, and greenhouse studies were conducted. The rhizotron study showed no differences in the percentage of roots having root hairs regardless of water stress treatments imposed 20 to 50 and 50 to 80 days after planting (DAP). Thirty‐seven to 43% of the roots had root hairs. In the field, peanut root systems growing within dialysis root bags in a Tifton loamy sand (fine‐loamy, siliceous, thermic Plinthic Kandiudults) showed a significant increase in root hair formation from 7% at 70 DAP to 31% at harvest. In the greenhouse using three soil types, Greenville fine sandy loam (clayey, kaolinitic, thermic Rhodic Kandiudults), Tifton loamy sand, and a 4:1 coarse sand:fritted clay mixture (rhizotron), soil type was found to affect the percentage of roots having root hairs. Roots growing in the Tifton, sand:fritted clay mixture, and Greenville soils had 47, 17, and 14% root hairs, respectively. In all studies, the rosette form of root hair around lateral initiates was observed. Approximately 66% of the lateral initiates expressed rosette‐type root hairs. Mycorrhizal infection, though insufficient to significantly affect nutrient uptake, was greater with the rhizotron (18%) than the Greenville (6%) and Tifton soils (3%). There may be a possible interaction between root hair occurrence and mycorrhizae infection.
Field‐Grown Tomato Response to Carbonated Water Application
Authors: Novero R. , Smith D. H. , Moore F. D. , Shanahan J. F. , d'Andria R. 
Published: July 2010

AbstractDirect release of CO2 gas to achieve a cost‐effective method of atmospheric CO2 enrichment has not been proven feasible under field conditions. We hypothesized that greater efficiency of application would occur by applying CO2 via carbonated water and that application would also result in beneficial modifications of the soil environment. Our objectives were to evaluate crop, soil, and atmospheric CO2 responses to application of carbonated water under pressure through a drip irrigation system. Studies were conducted under mulched and unmulched conditions in 1988 using tomato (Lycopersicon esculentum Mill.). In 1989, carbonated water was applied at approximately 2‐, 4‐, and 6‐d intervals to determine the effect of irrigation frequency. In 1988, a positive yield response of 9% was obtained in the presence of mulch. No response was observed in open beds. Fruit yields were increased at all three irrigation frequencies in 1989, with increases in fresh‐market and total fruit yields averaging 16.4 and 15.9%, respectively. Atmospheric enrichment was observed during carbonated water application, but residual enrichment between irrigations was difficult to detect. Significant increase in soil‐air CO2 from carbonated water application was noted throughout the intervals between successive irrigation events. Carbonated water application also decreased soil pH for periods of up to 5 d after irrigation and increased apparent uptake of P, K, Ca, Mg, Zn, Fe, Mn, Cu, and B. Based on the limited duration of enrichment relative to the entire growing season for any of the carbonated water treatments, the yield responses observed could not be attributed solely to atmospheric enrichment. Thus, we conclude that yield increases resulted from the combined effects of limited atmospheric CO2 enrichment and soil environment modifications leading to improved nutrient uptake.
No‐Till Winter Wheat Dry Matter and Tissue Nitrogen Response to Nitrogen Fertilizer Form and Placement
Authors: Johnston A. M. , Fowler D. B. 
Published: July 2010

AbstractExpansion of winter wheat (Triticum aestivum L.) production into the high winterkill risk regions of the Canadian prairies has been achieved by no‐till seeding into standing stubble immediately after harvest of the previous crop. Seven field trials were conducted in Saskatchewan to evaluate the seasonal pattern of dry matter and N accumulation of no‐till winter wheat. The fertilizer treatments included the currently recommended early (20 April) spring broadcast ammonium nitrate (AN) and early spring broadcast and surface band applied urea and urea‐ammonium nitrate (UAN) solution. In four of the seven trials, late (12 May) AN and urea were also applied. Nitrogen fertilizer was applied at 0, 34, 67, 101, and 202 kg N ha−1. Mean maximum dry matter and N yields were established by Zadoks Growth Stage 65 (ZGS65) and ZGS45, respectively. Subsequent losses of both dry matter and N were observed under conditions of high evaporative demand and low precipitation. When rainfall was more favorable and N supply abundant, N and dry matter yields increased through the growing season to harvest. Increased N rates increased N uptake and amplified plant‐N and dry matter losses. Growing season environmental conditions and plant‐available‐N levels also played an important role in determining the efficiency of N translocation to the seed. Early broadcast AN produced larger dry matter and N‐yield responses than all other fertilizer treatments. While surface band applied urea showed no advantage over early broadcast urea, surface band applied UAN increased dry matter yield and N uptake over broadcast sprayed UAN. Average dry matter (N) yield‐N response for early broadcast urea, surface band applied urea and surface band applied UAN treatments were 93 (89%) of those recorded for early broadcast AN. The broadcast sprayed UAN treatment dry matter and N yield‐N responses were 81% of early broadcast AN. Compared with early broadcast AN and urea, late broadcast AN and urea produced lower dry matter yields and delayed N uptake. Average late broadcast AN and urea dry matter (N) yield‐N responses were 63 (85%) of those recorded for early broadcast AN and urea. These observations indicate that differences in dry matter and N‐yield responses for different N forms and placement methods are established early in the growing season and maintained through to maturity.
Use of a Chlorophyll Meter to Predict Sidedress Nitrogen Requirements for Maize
Authors: Piekkielek W. P. , Fox R. H.. 
Published: July 2010

AbstractMost N testing methods require collecting, processing and analyzing of either soil or plant tissue samples. In 1987 we began a study to determine if chlorophyll readings of maize (Zea mays L.) made in the field with a portable chlorophyll meter could be used to predict soil N availabilities and sidedress fertilizer N requirements. The meter was tested over a 3‐yr period on 67 N response experiments located in central and southern Pennsylvania. At the six‐leaf stage of maize the chlorophyll meter reading of the fifth leaf was an accurate predictor of whether maize would respond to sidedress N fertilizer. A chlorophyll meter reading of 43.4 meter units was found to be the best critical level to separate responsive and nonresponsive sites. The chlorophyll meter method was similar in its accuracy in separating N responsive sites from nonresponsive sites to several proposed soil N availability tests including the soil NO3 concentration in the surface 20 cm of soil at planting, the UV absorbance at 200 nm of a 0.01 M NaHCO3 extract of the surface 20 cm of soil at planting, and the soil NO3 concentration in the surface 30 cm of soil 4 to 5 wk after plant emergence. The chlorophyll meter test was not well enough correlated with soil N supplying capability (r = 0.59) to determine sidedress N fertilizer rates for N responsive sites.
Small‐Grain Equivalent of Mixed Vegetation for Wind Erosion Control and Prediction
Authors: Skidmore E.L. , Nelson R.G. 
Published: July 2010

AbstractControl and prediction of wind erosion require knowledge of the effectiveness of surface vegetative cover. The effectiveness is usually referenced to as small‐grain equivalent. The procedure used to convert mixed vegetation to small‐grain equivalent was found faulty. Improper weighting of regression coefficients caused the conversion procedure to predict that adding crop residue decreased small‐grain equivalent. Therefore, the purpose of this analysis was to improve the conversion of mixed vegetation to a small‐grain equivalent. The new expression derived for this purpose gave a logical conversion where the previous procedure failed. It did not predict a decreasing small‐grain equivalent with increased soybean [Glycine max (L.) Merr.] residue in the 0 to 300 kg/ha range as did the former method. Applied to the same data that were used for testing the previous procedure, the new procedure reduced the error by almost 50%. The new procedure improves the conversion of mixed vegetation to small‐grain equivalent.
Lowland Rice Yield as Affected by Timing of Water Deficit and Nitrogen Fertilization
Authors: Castillo E. G. , Buresh R. J. , Ingram K. T. 
Published: July 2010

AbstractWater deficit and insufficient N supply are important constraints to the productivity of rainfed lowland rice (Oryzu sativa L.). To determine the effects of water deficit and urea application timing on yield and N accumulation of lowland rice, a field experiment was conducted for 2 yr on an Andaqueptic Haplaquoll in the Philippines. Water regimes imposed in the dry season were continuously flooded, not flooded or irrigated from 15 to 35 d after transplanting (DT), and not flooded or irrigated from 41 to 63 DT. Urea treatments in factorial combination with the water regimes were no applied N, early N (80 kg N ha−1, one‐half basal incorporated and one‐half broadcast at 37 DT), and late N (80 kg N ha−1, one‐half broadcast at 11 DT and onehalf broadcast at 65 DT). Water deficit at 15 to 35 DT significantly reduced mean grain yield (26%), straw yield (21%), grain N accumulation (31%), and straw N accumulation (31%). Water deficit at 41 to 63 DT, which ended before panicle emergence, decreased yield and N uptake, but less than water deficit at 15 to 35 DT. Nitrogen application consistently increased grain yield even when the rice crop was exposed to water deficit. Mean grain yields were greater (P < 0.05) for early N (5.7 Mg ha−1) than late N (3.7 Mg ha−1) in 1986 but not in 1987 (4.1 and 3.8 Mg ha−1, respectively). Water‐by‐N interactions were not significant for grain or straw yields and grain or straw N accumulations. The N timing most effective for continuously irrgated rice was also most effective for rice exposed to moderate water deficit before flowering.
Impact Absorption Characteristics on Turf and Soil Surfaces
Authors: Rogers J. N. , Waddington D. V. 
Published: July 2010

AbstractPlaying quality of athletic fields is critical to an athlete from the safety and performance standpoints. Use intensity and maintenance practices affect playing surface quality and impact characteristics within and among fields. The objective of this study was to quantitatively assess the effects of cutting height, compaction, soil water content (date), and turf cover on the impact absorption characteristics of Kentucky bluegrass (Poa pratensis L.) turf. Treatments were four cutting heights (0 [bare soil], 19, 38, and 57 mm), and two compaction levels (with and without) for Exp. I, and three cutting heights (19, 38, and 57 mm), two compaction levels, and three surface types (full turf, no verdure, and no thatch) in Exp. II. Surface impact characteristics measured were peak deceleration, time to peak deceleration, and impact duration. Two hammer weights, 2.25 kg and 0.5 kg, were used to assess impact characteristics on four dates and to obtain data for soil water conditions of 0.263, 0.197, 0.163, and 0.064 kg kg−1. The highest peak deceleration values and shortest time periods were associated with the periods of low soil water and compacted conditions. Only the 0.5‐kg hammer detected differences in impact absorption characteristics between cutting heights. Significant cutting height‐by‐compaction‐ by‐date interactions occurred for each impact characteristic, indicating interdependence of one of the factors on another. It appears that field management practices that influence soil water content, soil compaction, and turf cover are more important than cutting height in altering the impact absorption capability of Kentucky bluegrass turf.
Seedling Emergence of Yellow‐Flowered Alfalfa as Influenced by Seed Weight and Planting Depth
Authors: Townsend C. E. 
Published: July 2010

AbstractYellow‐flowered alfalfa [Medicago sativa L. subsp. falcata (L.) Arcangeli] is well‐adapted to rangeland sites in the central and northern Great Plains, but its early seedlings vigor is poor compared to that of purple‐flowered alfalfa (M. sativa L. subsp. sativa). The objectives of this study were to (i) develop germplasms with a high percentage of falcata traits and (ii) determine the effect of seed weight and depth of planting on seedling emergence. Germplasm with 18 seed‐weight classes (1.0 to 2.1 g/l000 seeds) was developed and evaluated for seedling emergence from a 1.9‐cm depth of planting in a Nunn clay loam soil (fine, montmorillonitic, mesic Aridic Argiustolls) on two dates of planting at Fort Collins, CO, in 1986. Seed weight was significantly (P ≤ 0.01) correlated with seedling emergence at both the first (r = 0.69) and second (r = 0.79) dates of planting. The 18 classes were consolidated into six classes whose mean seed weights were 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0 g/1000 seeds. The six classes were evaluated for seedling emergence from 1.3‐, 2.5‐, and 3.8‐cm depths of planting at Fort Collins, from 1987 through 1990. The six seed‐weight classes and three depths of planting differed significantly (P ≤ 0.05 or ≤ 0.01) for seedling emergence at each of six planting dates. In general, the heavier seedweight classes had the highest seedling emergence over all depths of planting and, as expected, seedling emergence decreased with increased depth of planting. Seedling emergence of yellow‐flowered alfalfa can be increased by selecting for high seed weight.
Structured Heterogeneity of Soil pH and Grain Yield of Rice and Wheat Grown in a Sodic Soil
Authors: Samra J. S. , Rajput R. K. , Katyal V. 
Published: July 2010

AbstractConventional statistical methods that assume independent random variation are inadequate when dealing with spatially dependent heterogeneity. Structural analysis of heterogeneity was performed for soil pH and grain yields of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) grown under uniform management in a sodic soil (Natric Haplustalf). Relative efficiencies of field sampling designs and methods of analysis were computed. The coefficients of variation (CV) for the yield of rice and a subsequent wheat crop were 16 and 5490, respectively. The two‐way trend variation in soil pH was 21% of variance before rice planting and 28% after wheat harvest. The same parameter for the grain yield of rice and wheat was 12 and 28%, respectively. Variogram analysis revealed that locally structured variation of soil pH was 30 and 48% of variance before rice planting and after wheat harvest, respectively. Structured heterogeneity for grain yield was 16% in rice and 59% in wheat. Soil pH heterogeneity effects on rice were of lower magnitude than with wheat. The relative efficiency of Wilkinson's nearest neighbor analysis as compared to a randomized block design varied from 623 to 1682% depending on size and shape of the plot. This indicates that a substantial improvement in experimental precision is possible by taking account of positional effects of observation plots.
Modeling Sorghum Seedling Establishment from Soil Wetness and Temperature of Drying Seed Zones
Authors: Brar G. S. , Steiner J. L. , Unger P. W. , Prihar S. S. 
Published: July 2010

AbstractExisting crop simulation models predict emergence based on experimental results on the effects of soil temperature and water in systems sealed against evaporation. Under field conditions, however, the seed zone is open to evaporation. Seed zone water decreases with time and is often inversely related to soil temperature. Little is known about the combined effects of soil temperature and water on sorghum [Sorghum bicolor (L.) Moench] emergence rates in drying seed zones. Therefore, our objective was to study this and to model the effect to predict seedling stand establishment. Greenhouse experiments were conducted to study sorghum emergence at six constant temperatures (8.8, 15.9, 20.5, 25.2, 30.2, and 35.8 °C) attained on a thermogradient plate, and three initial soil water matric potentials (Ψ3) (−0.03, −0.1, and −0.3 MPa), using a Pullman clay loam. Emergence and plant height were recorded daily for 2 wk and root length was measured at termination of the experiment. We developed a sorghum stand establishment model that utilizes heat units and indices of emergence or growth as input parameters to predict emergence and root and shoot growth of seedlings. Optimum sorghum emergence (> 80%) was obtained at temperatures of 20.5 to 30.2 °C, and −0.03 to −0.1 MPa Ψ3. Furthermore, combinations of cool temperature (15.9 °C) and (6: of −0.1 MPa as well as warm temperature (35.8 °C) and Ψ of −0.03 MPa produced satisfactory emergence (> 80%). Sorghum emergence regressed with thermal emergence index yielded a highly significant (P < 0.0001) positive nonlinear correlation (Adj. R2 = 0.62). Similarly, main axis root length, lateral root length, and plant height regressed with thermal indices of main axis root length, laterlal root length, and shoot growth yielded significant (P < 0.0001) positive, nonlinear correlations (Adj. R2 = 0.46, 0.70, and 0.77, respectively). The model should provide more realistic sorghum emergence predictions than models developed in systems closed to evaporation.
Bermudagrass Response to Reactive Layer Coated Fertilizers
Authors: Peacock Charles H. , DiPaola Joseph M. 
Published: July 2010

AbstractRecent polymer chemistry research has introduced a material manufactured by a reactive layer coating (RLC) process which shows promise for minimizing N loss through leaching. Laboratory studies have shown that RLC coated ureas were successful at slowing N release and have potential as slow‐release N fertilizers for turf. This field study compared ‘Tifway’ bermudagrass (Cynodon dactylon L. Pers. ✕ C. transvaalensis Burtt‐Davey) response to RLC ureas having different coating weights (thicknesses) with other conventional N carriers. Bermudagrass turf quality (1 – 9 scale, 9 = best) and shoot growth response observations were made over a 10‐wk period to determine if various coating thicknesses would allow adequate N release to provide a response equivalent to other N sources. Best turf quality (7.4) for the 2‐yr study was for RLC carriers that combined slow and intermediate release rate RLC ureas (12.5% or 10.8% coating + 7.2% coating) with urea. Overall turf quality was lowest (6.5) in 1987 for the RLC with the slowest release rate, a 12.5% coating (10 g N m−2), 9.9% RLC coating + urea (10 g N m−2), and urea (5 g N m−2). In 1988 the RLC with the slowest release had a 10.8% coating (10 g N m−2). Shoot growth rate in 1987 was greatest (11.9 mm wk−1) for the RLC material with a 7.2% coating at 10 g N m−2 and lowest for the RLC 12.5% coating (5.3 mm wk−1). By comparison, urea applied at 5 g N m−2 resulted in intermediate turf growth (9.4 mm wk−1). In 1988, shoot growth rate was greatest for the 10.8% RLC + 7.2% RLC + urea combination material applied at 10 g N m−2. Equivalent growth was noted for the urea + 9.9% RLC (5g n m−2) and sulfur coated urea (10 g N m−2) materials. Use of slow release RLC N carriers as turf fertilizers showed promise as a combination material with urea.
Influences of Soil Environment on Biomass and Nitrogen Accumulation Rates of Orchardgrass
Authors: Stout W.L. , Jung G.A. 
Published: July 2010

AbstractGrasslands are the basis for a stable agriculture in the northeast USA. However, knowledge of the interactive effects of the diverse soils and climate of this region on grassland production remains scant. Our objective was to quantify the effect of soil environment on grassland biosmass and N accumulation. The study was conducted for 3 yr on four sites in central Pennsylvania selected for soil water holding capacity and temperature regime. Orchardgrass (Dactylis glomerata L.) was treated with a split application (50%/50%) of 0, 84, and 168 kg N ha−1 of 15N depleted ammonium nitrate. Biweekly biomass samples were taken starting 30 April of each year and continuing until the grass heading stage. At heading, plots were cut at a 7.5‐cm stubble height and all herbage removed. Plots were refertilized with the second half of the N and monthly biomass sampling commenced on 31 July and continued until 31 October. Biomass samples were dried at 60 °C and weighed for yield. Subsamples of the dried material were analyzed for N and isotope ratio. Spring biomass accumulation rates ranged from 60.0 to 112.0 kg ha−1 day−1. Soil N, N fertilization and temperature all were factors controlling spring biomass accumulation rate. Fall biomass accumulation rate was controlled by N fertilization alone. Spring fertilizer N accumulation rates range from 0.078 to 0.72 kg ha−1 day−1 and were largely controlled by N fertilization. Spring total N uptake rates ranged from 0.461 to 2.20 kg ha−1 day−1 and were controlled by soil N levels and N fertilization. Fertilizer N recovery was about 42% for the spring growth period but only about 15% for the fall growth period.