bluuebunny/crossref_metadata_2025_split huggingface dataset:
Salt Distribution and Water Consumption from a Water Table With and Without a Crop1
Authors: Saleh Hamed H. , Troeh Frederick R. 
Published: July 2010

AbstractThis study was undertaken to quantify the soil salinization process and relate it to soil depth, cropping, and water table variables. Such information has been needed but unavailable. Data were gathered by measuring the upward movement of water and salt from simulated groundwater. The work was done with 30‐cm square soil columns 50 and 75‐cm tall that were suspended in trays of artificial groundwater. The experiment was located in a greenhouse to create an arid environment. Sudangrass [Sorghum sudanense (Piper) Stapf.] was grown on half of the columns and the others were fallowed. Water consumption was increased by the shallower depth to groundwater, by the less saline groundwater (electrical conductivity 4 mmhos/cm vs. 11) and by the presence of a crop. The crop had little effect on the salt concentration at the moist surface of the 50‐cm columns but reduced the salt accumulation at the already drier and less salty surfaces of the taller columns. Salt accumulation in the root zone was increased by the presence of a crop.
No‐Till Soybeans in Forage Grass Sod1
Authors: Elkins D. M. , George J. D. , Birchett G. E. 
Published: July 2010

AbstractNo‐till planting of soybeans [Glycine mar (L.) Merr.] is a widespread practice in the midwestern and southern U.S.A. However, the vast majority of this hectarage is double‐crop soybeans planted in wheat (Triticum aestivum L.) or another small grain after grain harvest. Occasionally, soybeans have been planted in a chemically‐controlled winter cover crop. Little work has been reported on the possible merits of planting soybeans in a grass sod, which would offer the advantages of reduced soil erosion hazards and greater flexibility in soybean production systems.Field studies were designed to investigate the success of no‐till soybean production in forage sod. The soils representing different sites and experiments were Weir silt loam (Typic Ochraqualf), Stoy silt loam (Aquic Hapludalf), Alford silt loam (Typic Hapludalf), and Ebbert silt loam (Argiaquic Argialboll). Soybeans were planted in a tall fescue (Festuca arundinacea Schreb.) sod for 4 years at the Carbondale location, and for 2 years in Kentucky bluegrass (Poa pratensis L.) at the Belleville location in southern Illinois. When rainfall was adequate, no‐till soybean production in grass sods was highly successful, with yields as much as 4,308 kg/ha in tall fescue in 1977 and 4,704 kg/ha in tall fescue and 4,119 in Kentucky bluegrass in 1979. In the 2 years of plentiful moisture, adjusted herbicide rates allowed persistence or autumn regrowth of up to 40% of the forage grass, which could be an important factor regarding autumn and winter grazing and erosion control.The best herbicide treatments in these studies for allowing a combination of soybean yield and forage grass persistence or regrowth was paraquat (1, 1′‐dimethyl‐4,4′‐bipyridinium ion) alone at 0.6 kg/ha, paraquat at 0.6 kg/ha in combination with metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetamide] at 3.4 or 4.5 kg/ha or with mefluidide{N‐[2,4‐dimethyl‐5‐[[trifluoromethyl) sulfonyl] amino] phenyl] acetamide} at 0.6 kg/ha. Another promising combination was glyphosate [N‐(phosphonomethyl) glycine] at 1.1 kg/ha plus metribuzin [4‐amino‐6‐tert‐butyl‐3(methylthio)‐as‐triazin‐5 (4H)‐one] at 1.1 kg/ha. All of these treatments resulted in no‐till soybean yields exceeding 4,000 kg/ha, when growing season rainfall was adequate, and tall fescue maintenance or regrowth resulting in 25 to 40% sod cover in the autumn.
Long‐term N‐P Fertilizer and Climate Influences on Morphology and Yield Components of Spring Wheat1
Authors: Black A. L. 
Published: July 2010

AbstractThe long‐term availability of one‐time, high‐rate, broadcast application of P fertilizer has not been adequately evaluated in relation to variable water supplies and N fertilization for optimum production of spring wheat (Triticum aestivum L.) on dryland. Additional knowledge of the interrelationship of plant morphological characteristics, plant growth, and components of grain yield to soil fertility will be useful in the development and validation of wheat yield models.Spring wheat was grown for 12 years (winter wheat in 1 year) in two separate alternate crop‐fallow plot series on a Williams loam (fine‐loamy, mixed, Typic Argiborolls). Phosphorus fertilizer as treble superphosphate was broadcast at 0, 22, 45, 90, and 180 kg P/ha at the beginning of the study in 1967 or 1968. Ammonium nitrate was broadcast each crop year at 0, 45, and 90 kg N/ha. With relatively shallow sweep‐tillage, soluble P increased proportionate to rate of P applied and remained relatively high over the 12‐year period in the 0 to 15.2 cm soil depth. Significant grain yield responses to initial and residual P fertilization occurred up to a soluble P level of about 15 ppm independent of available water supplies. In contrast, yield responses to N fertilization increased as total available water supplies increased from 22.6 to 52.8 cm.Number of heads/m2 could be predicted more reliably from number of adventitious roots/plant than from number of tillers. Number of head/m2 accounted for 86% of the yield variance associated with years (climate) and N‐P fertilizer treatments excluding one disease‐year when number of kernels/head was significantly decreased. Combining number of heads/m2 and kernels/head accounted for 91% of the yield variance associated with fertilizer treatments over all years combined. Predicting grain yields from dry matter production at tillering or heading was unsatisfactory compared to yield predictions based on total dry matter production or straw production at maturity.
Response of ‘Tifton 44’ and ‘Coastal’ Bermudagrass to Soil pH, K, and N Source1
Authors: Belesky D. P. , Wilkinson S. R. 
Published: July 2010

AbstractA winter‐hardy bermudagrass [Cynodon dactylon (L.) Pers.], ‘Tifton 44’ with high productivity and nutritive quality should expand the range of bermudagrass production. Both productivity and winter survival are dependent upon soil fertility conditions. An investigation was designed to compare the productivity, winter survival, and mineral composition of ‘Coastal’ and Tifton 44 bermudagrass grown in Cecil sandy loam (Typic Hapludult, clayey, kaolinitic, thermic) soil as affected by pH level (4.1, 5.5, 6.5) rate of K (0, 70, 140 kg K/ha) and N source (NaNO3, urea) under greenhouse conditions. More sprigs of both cultivars survived establishment when treated with urea rather than NaNO3, regardless of K level. Survival was also improved at pH 5.5 and 6.5 over 4.1 for either cultivar. Coastal tended to outyield Tifton 44 when expressed on a yield per pot. Yield of Coastal was improved with increasing K rate regardless of N source while Tifton 44 yield was not improved by increasing K when NaNO3 was applied. Concentrations of K, Na, and Mg were greater in Tifton 44 than in Coastal, whereas Ca was greater in Coastal than in Tifton 44. Concentrations of Mg in both cultivars were higher with urea fertilization than with NaNO3 at pH 5.5 and 6.5. There were no significant trends for the micronutrients Cu, Mn, Fe, and Zn although increasing pH tended to decrease Mn and Zn concentrations for either cultivar. Winter survival was assessed by maintaining plants out of doors under field conditions at Blairsville, Ga., UGA Mountain Branch Experiment Station. Root and rhizome weights were significantly increased by applications of K to Tifton 44 which survived exposure to winter conditions at Blairsville, Ga. while Coastal did not survive winter exposure.
Analysis of Combined Experiments1
Authors: McIntosh M. S. 
Published: July 2010

AbstractMost field experiments are conducted over two or more locations or years, yet statistical references do not contain sufficient detail for complete analysis. The purpose of this paper is to provide a reference for analysis of combined experiments. Tables include sources of variation, degrees of freedom, and F‐ratios for one factor and split‐plot experiments combined over locations and/or years. The F‐ratios are given for fixed, mixed, and random models.
Influence of pH on Yield and N and P Nutrition of Alfalfa Grown on an Andic Mission Silt Loam1
Authors: Mahler R. L. 
Published: July 2010

AbstractYields of alfalfa (Medicago sativa) average only 7500 kg/ha on ash‐influenced Mission silt loam (coarse‐silty, mixed, frigid Andic Fragiochrepts) in northern Idaho. This relatively poor growth is commonly attributed to the chemical characteristics of these andic soils. The objectives of this study were to: (1) determine the effect of soil pH on alfalfa establishment and growth, (2) N and P uptake, (3) Rhizobium meliloti survival, and (4) P availability in a Mission soil under greenhouse conditions. Aluminum sulfate and finely ground calcium carbonate were used to adjust soil pH. Soil pH values were 4.8, 5.1, 5.6, 6.2, 6.4, 6.9, 7.0, and 7.4. Alfalfa was grown in 150‐mm pots in the greenhouse and harvested five times at approximately 20‐day intervals. Yield was measured and plant material was analyzed for total N and P. Rhizobium meliloti populations were monitored using the most probable number (MPN) technique and available soil P was determined using sodium acetate extractant. Manipulation of pH in the Mission soil was found to have a significant effect on alfalfa growth, tissue N and P concentration, survival of R. meliloti in the soil, and on sodium acetate extractable soil P. In general, tested parameters increased with increasing pH. Greatest forage yield occurred at a pH of 7.4. The andic nature of the Mission soil requires a pH adjustment above pH 6.6 for acceptable alfalfa establishment and yields, probably because of the relatively high degree of Al saturation that occurred at pH values below 6.6. This is in sharp contrast to non‐andic northern Idaho soils where alfalfa yields are usually not adversely affected above pH 5.6.
Carbon Dioxide and Agricultural Yield: An Assemblage and Analysis of 430 Prior Observations1
Authors: Kimball B. A. 
Published: July 2010

AbstractThe probable effect of the increasing global atmospheric CO2 concentration on agricultural yields was evaluated. More than 430 observations of the yield of 37 species grown with CO2 enrichment were extracted from more than 70 reports published during the past 64 years. Most of the studies were performed in greenhouses or growth chambers. Open fields might respond less than greenhouses or growth chambers to increased CO2 because nutrient levels in general world‐wide agriculture are lower than those in the indoor studies, or open fields might respond more because light levels are generally higher outside. The data also were dominated by high value crops, but results should be applicable to the three‐fourths of the world agriculture represented by the C3 crops and possibly to the remaining C4 crops as well. Keeping these limitations of the data in mind, the analysis showed that yields probably will increase by 33% (with a 99.9% confidence interval from 24 to 43%) with a doubling of atmospheric CO2 concentration.
Costs of Measuring Leaf Area Index of Corn1
Authors: Daughtry C. S. T. , Hollinger S. E. 
Published: July 2010

AbstractLeaf area index (LAI) is an important biophysical descriptor of crop canopies. Accurate measurements of W are laborious and time‐consuming. Many methods of measuring LAI of corn (Zea maysL.) have been reported and vary greatly in their accuracy, precision, bias, and ease of measurement. We examined the magnitude of plant‐to‐plant variability of leaf area of corn plants selected from uniform plots and evaluated four representative methods for measuring LAI. The number of plants required and the relative costs for each sampling method were calculated to detect 10, 20, and 50% differences in W using 0.05 and 0.01 tests of significance and a 90% probability of success (β = 0.1). The natural variability of leaf area per corn plant was nearly 10%. Additional variability or experimental error may be introduced by the measurement technique employed and by nonuniformity within the plot. Direct measurement of leaf area with an electronic area meter had the lowest coefficient of variance (CV), required that the fewest plants be sampled, but required approximately the same amount of time as the leaf area/weight ratio method to detect comparable differences. Indirect methods based on measurements of length and width of leaves required more plants but less total time than the direct method. Unless the coefficients for converting length and width to area are verified frequently, the indirect methods may be biased. When true differences in LAI among treatments exceed 50% of mean, all four methods are equal. The method of choice depends on the resources available, the differences to be detected, and what additional information, such as leaf weight or stalk weight, is also desired.
Growth and Water Use of Tall Fescue as Influenced by Several Soil Drying Cycles1
Authors: King M. J. , Bush L. P. 
Published: July 2010

AbstractMany investigations have studied various physiological processes using plants watered on a schedule with the effect of this watering schedule seldom considered significant. An understanding of the effect of watering frequency on growth and water use is required to understand water stress tolerance of tall fescue (Festuca arundinacea Schreb.). Experiments were designed to evaluate the effect of watering schedule in greenhouse grown tall fescue on growth, water use, and meristem tissue water status. Growth and water use as well as water, osmotic, and turgor potential of the leaf meristematic region were measured on tall fescue seedlings that had been exposed to several Maury soil (a fine, mixed, mesic Typic Paleudalfs) drying cycles (stressed and daily watered). Growth, measured as leaf extension rate (LER), was greater for seedlings watered to field capacity every 4th day than daily watered seedlings when soil of both treatments was allowed to dry. No significant difference in water potential or osmotic potential was observed during the experiment, and the differential LER was not dependent on turgor potential of the meristematic area which was similar to both treatments. Water use was 50 to 100% higher in control seedlings during the first 48 h of a soil drying cycle than in stressed seedlings. After several soil drying cycles the enhanced growth of stressed plants increased as high as 280%, then declined over the next 24 days of daily watering to about 50% above the control. The enhanced LER did not result in greater shoot fresh weights, but, repeated soil drying depressed root development. Consequently, growth, water status, and water use by tall fescue plants during an experiment must be evaluated in terms of the plants prior water stress history.
Performance of Selected Soybean Cultivars in a Field Infested with Mixtures of Root‐Knot, Soybean Cyst, and Other Phytonematodes1
Authors: Weaver D. B. , Rodriguez‐Kabana R. , Robertson D. G. 
Published: July 2010

AbstractInformation on relative nematode resistance in soybean cultivars is needed because of recent Environmental Protection Agency action prohibiting the use of ethylene dibromide as a soil fumigant for nematode control. Performance of 10 soybean [Glycine max (L.) Merr.] cultivars was studied near Elberta, AL for 2 years in a Eustis loamy fine sand (sandy, siliceous, thermic, Psammentic Paleudults) that was heavily infested with Southern root‐knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood] and lightly infested with race 3 of the soybean cyst nematode (Heterodera glycines Ichinohe). The objective was to determine relative resistance to nematodes among cultivars by measuring yield and nematode numbers in unfumigated plots and in plots fumigated with 18.7 L ha−1 ethylene dibromide. Seed yields of all cultivars were increased an average of 396% in 1982, and 138% in 1983 by fumigation. ‘Foster’ and ‘Kirby’ had the highest seed yields in unfumigated soil. All cultivars sustained significant nematode larval populations near harvest with greater numbers associated with the higher yielding cultivars. Foster and Kirby offer a practical approach to management of heteroderid nematodes in the absence of an economical, efficient nematicide.
Wheat Seedling Growth and Developmental Response to Incident Photosynthetically Active Radiation1
Authors: Rickman R. W. , Klepper Betty , Peterson Curt M. 
Published: July 2010

AbstractShade from residues of previous crops in high residue seedbeds may limit development of winter cereal seedlings. A growth chamber experiment with photosynthetic photon flux densities of 140, 275, or 500 µmol−2s−1 for 12 h each day was designed to reveal the growth and development patterns of winter wheat (Triticum aestivum L. em Thell.) under light limiting conditions. Daily totals of light received during winter months at 46°N Lat are within this range. Leaf and tiller growth and development were observed daily on 6 to 12 separately potted plants in each of seven treatments for 1 month after emergence. At 140 µmol m−2s−1, a higher fraction of specific tiller buds failed to elongate than at either higher irradiance. Failure to elongate one tiller bud did not influence the point of development of subsequent tillers. Plants developed at 0.0097,0.0117, and 0.0138 leaves per degree day (0°C base) under 140, 275, and 500 µmol m−2s−1 treatments, respectively. An average of only four tillers per plant were present after 27 days under 140 µmol m−2s−1 while 12 tillers per plant were produced under 500 µmol m−2s−1. The basic relationship between main stem leaf and individual tiller development was not changed by different amounts of light. Specific tillers appeared at essentially the same point in plant development regardless of irradiance. At 140 µmol m−2s−1, the slower leaf development and reduced tillering both contributed to reduce plant weights to only one‐fifth those from the 500 µmol m−2s−1 treatment. The irradiance required for maximum development rate of winter wheat seedlings exceeds that expected in shaded areas of a seedbed from November through February at 46° N Lat. Based on this experiment, irradiance will not change the point of development of specific tillers relative to main stem leaf development. Irradiance will influence the fraction of plants with specific tillers and the rate (leaves per degree day) of leaf appearance. Leaf development rate (leaves per degree day) appears to be buffered by short term (a few days) energy reserves. Winter wheat seedlings that are shaded over winter will skip a higher fraction of the early tillers (T0, T1) than unshaded seedlings, reducing the population of potentially large heads.
Corn Irrigation Scheduling in Humid Regions on Sandy Soils with Tillage Pans1
Authors: Cassel D. K. , Martin C. K. , Lambert J. R. 
Published: July 2010

AbstractSeveral droughts during the past decade in humid regions of the USA, especially the Southeast, have intensified the interest in supplemental irrigation. One objective of this study was to evaluate the effect of supplemental irrigation in a humid environment on corn (Zea maysL.) production on an Atlantic Coastal Plain soil having a tillage pan. A second objective was to evaluate two alternative techniques for scheduling supplemental irrigation in humid regions. The study, conducted on a Wagram soil (Arenic Paleudults)‐Norfolk soil (Typic Paleudults) from 1979 to 1981, employed a split plot design with water level (irrigation scheduling) as the main block. Water levels were control or dryland (W1), scheduled irrigation water applications based on a computerized water balance model (W2), and scheduled water applications based on tensiometer measurements (W3). Subplot treatments were time of N application in 1979 and 1980 and cultivation intensity in 1981. Compared with a normal rainfall of 447 mm during the growing season, 464, 262, and 220 mm fell during 1979, 1980, and 1981, respectively. The average amount of irrigation water applied over the 3‐yr period based on the water balance model was 40 mm greater than the 3‐yr average of 179 mm applied based on the tensiometers. Grain yield as affected by subplot treatment was not significantly different for any year. Mean grain yields for the 3‐yr period were 2.58, 7.73, and 8.14 Mg ha−1, for treatments W1, W2, and W3, respectively. Either irrigation scheduling method offers large yield improvements in drier years, but no significant yield difference occurred for the two scheduling techniques. In the wetter year 1979, irrigation increased yield by 2.45 Mg ha−1, whereas in the dryer years of 1980 and 1981 the increases were 6.53 and 7.06 Mg ha‐1, respectively.
Molybdenum Limitations to Alfalfa Growth and Nitrogen Content on a Moderately Acid, High‐Phosphorus Soil1
Authors: Doerge T. A. , Bottomley P. J. , Gardner E. H. 
Published: July 2010

AbstractAlfalfa (Medicago sativaL.) grown in an Aquultic Argixeroll at pH 5.5 had a low N content and produced very low yields even though soil and/or plant tissue analysis for Al, Mn, Ca, P, Mo, and Mg did not indicate deficiency or toxicity conditions. Field and greenhouse experiments with pH, Ca, N, and Mo variables were undertaken to characterize the factor(s) limiting production of alfalfa on this soil. Plants at all pH levels (5.5 to 6.4 in the field and 5.3 to 6.5 in the greenhouse) were well nodulated. Under greenhouse conditions the application of 1 mg Mo kg−1soil resulted in a total dry matter yield, total N uptake, and shoot N concentration of 9.87 g pot−1, 0.216 g pot−1, and 26.5 g kg−1, respectively, compared with corresponding values of 2.96, 0.040, and 20.6 for plants grown without Mo. The application of 714 mg N kg−1(greenhouse) and 672 kg N ha−1(field) as NH4NO3to alfalfa grown in unamended soil increased shoot dry matter production from 1.46 to 7.01 g pot−1in the greenhouse and 3.7 to 12.0 Mg ha−1under field conditions. No response in yield or nodulation to the application of CaSO4was measured. Responses to N and Mo, especially at the lower pH levels, suggested that the growth response to lime is due primarily to increased nodule efficiency, resulting from greater Mo availability as soil pH is raised. On moderately acidic fertile soils, the application of Mo to well‐nodulated but N‐deficient alfalfa may provide an economical, effective means for increasing production where low Mo availability is the major growth‐limiting factor.
Variability Among Plants in Dinitrogen Fixation (Acetylene Reduction) Rates by Field‐Grown Soybean1
Authors: Denison R. F. , Weisz P. R. , Sinclair T. R. 
Published: July 2010

AbstractHigh variability in acetylene reduction rates within cultivars and treatments has been a problem in evaluating treatment and cultivar effects. This study examined the sources of such variability, using field‐grown soybean [Glycinee max(L.) Merr.] plants. Acetylene reduction rate per plant was measured in situ for thinned and unthinned ‘Chippewa 64’ soybean near Ithaca, NY for well‐watered and drought‐stressed ‘Biloxi’ soybean in Gainesville, FL and for ‘Guelph’ soybean subject to extended photoperiods in Gainesville, FL. A number of morphological traits, including leaf weight per plant and nodule weight per plant, were measured for each plant assayed. In addition, the nodule gas conductance (permeability ✕ surface area) was computed for each plant. Correlations between these characteristics and acetylene reduction rate per plant were used to assess their relative importance. Acetylene reduction rate was consistently more closely correlated with nodule weight than with shoot characteristics. The highest correlation with acetylene reduction rate was, however, with nodule gas conductance. This correlation was highly significant across all treatments, cultivars, and maturity stage. Nodule gas conductance was concluded to play an important role in determining acetylene reduction rates in field‐grown plants.