bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Weather‐yield Function for Winter Wheat1
Authors: Feyerherm Arlin M. , Paulsen Gary M. 
Published: July 2010

AbstractCrop models require detailed knowledge of weather relationships for estimating and predicting yields. Objectives of this research were to develop a weather‐yield function (WYF) for winter wheat (Triticum aestivum L.) that had stable coefficients and minimal bias over a wide range of climates. The WYF was derived by regressing 966 location‐years of plot yields, adjusted for genetic gain, on candidate sets of weather‐related variables, applied N, location‐related variables, and time. Applied N, location, and time variables were included to reduce bias in coefficients of weather‐related variables. The portion of the regression function that included only weather‐related variables became the WYF. Observations used for regression came from a wide range of climates with high interannual variance. Values of WYF ranged from 546 to 2765 kg ha−1; they reflected deleterious effects of high and low temperatures and of inadequate and excessive moisture during the crop yield. Besides estimating the impact of weather on yields, the WYF can be applied to identifying yieldlimiting factors and managing wheat for increased productivity.
Evaluation of Cultivar and Nitrogen Management Options for Malting Barley1
Authors: Varvel G. E. , Severson R. K. 
Published: July 2010

AbstractMalting barley (Hordeum vulgare L.) requires constant evaluation of N management practices for individual cultivars because applied N directly affects both yield and malting properties. Knifed‐in versus broadcast applications of 0, 56, 112, and 168 kg N ha−1 were compared on Morex and Glenn cultivars in field experiments during 1981, 1982, and 1983 on a Hegne silty clay loam soil (fine, frigid Typic Calciaquolls). An additional cultivar, Robust, was added during 1983. Early plant, forage, and grain N concentrations, forage and grain yields, and percent plump kernels were measured. Cultivar and N rate main effects explained most differences in yield and malting quality after significant cultivar ✕ year, and N rate ✕ year interactions were found to be caused by differences in initial NO3‐N levels. Method of N application was not significant. Grain N concentrations never exceeded 21.6 g kg−1, a maximum set by the malting industry, during the 3 yr. On the basis of grain yields and percent plump kernels, Glenn was superior to Morex overall, but in 1983, Robust surpassed both Glenn and Morex at all levels of applied N. Each cultivar attained high yield levels and maintained malting quality with careful N management.
Effect of Tillage on Soybean Growth and Seed Production1
Authors: Webber C. L. , Gebhardt M. R. , Kerr H. D. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] grown without tillage often produces less grain on silty clay loam soils than soybean produced under conventional tillage. A 3‐yr (1982, 1983, and 1984) study was conducted to gain a better understanding of the factors affecting yield differences between conventional and no‐till soybean production systems on silty clay loam soils. The study was conducted near Columbia, MO, on a Mexico silt loam soil (Udollic and Mollic Ochraqualf). Conventional tillage consisted of spring moldboard plowing and secondary tillage. The no‐till treatment received a foliar application of glyphosate [N‐(phosphonomethyl) glycine] at the time of planting. Soybean grain yields were less for no‐till in 1982 (1890 kg/ha vs. 2260 kg/ha) and greater in 1983 (2310 kg/ha vs. 1510 kg/ha) and 1984 (1870 kg/ha vs. 1670 kg/ha). Seasonal rainfall was above average in 1982 and below average in 1983 and 1984. In 1983 and 1984, soybean in the no‐till plots depleted greater soil moisture at soil depths of 840 and 990 mm and had less plant water stress during podfilling, with afternoon leaf water potential measurements averaging 0.11 MPa greater in 1983 and 0.34 MPa greater in 1984, than soybean grown under conventional tillage. Conventionally tilled soybean had a greater yield potential due to greater vegetative growth, but with less than adequate rainfall the soybean in no‐till had less plant water stress, resulting in greater yields.
Design and Use of a Fully Automated Portable Rain Shelter System
Authors: Kvien C. S. , Branch W. D. 
Published: July 2010

AbstractAutomated rain shelters are usually fixed to one site. A three‐unit, portable, fully automated rain shelter system has been constructed for plant water stress research in Georgia. Each structure has a roof 8.6 by 7.2 m attached to four posts. Welded to the end of each post is an automotive wheel and tire assembly. Two smaller wheels (drive shaft driven by a geared‐down 746‐W 220 VAC motor) contact and drive the larger wheels. Two parallel irrigation pipe bumper rails guide the shelters. Movement onto and off of plots is controlled by one rain sensor and two limit switches. In studies with four sequential drought periods and a control, the total useful plot area is 0.05 ha.
Peanut‐Corn Intercrop Performance as Affected by Within‐Row Corn Spacing at a Constant Row Spacing
Authors: Calavan Kay M. , Weil Ray R. 
Published: July 2010

AbstractThe advantages of intercropping a cereal with a grain legume are often limited by the dominance of the cereal, which severely inhibits the legume. A field experiment was conducted in 1983 and 1984 in southern Maryland to determine the effects of within‐row corn (Zea mays L.) spacing on a peanut (Arachis hypogaea L.)‐corn intercrop. ‘Southern States 35A’ corn was planted in rows 1 m apart, with a double row of ‘Florunner’ peanut planted midway between. Peanut spacing was uniform, but within‐row corn spacing varied from 0.125 to 0.335 m in a systematic design with spacing in adjacent pairs of corn rows differing by 0.03 m. Separate sole‐crop plots of either four corn rows with 0.155‐m spacing or four double rows of peanut were used as controls. Yield components of both crops, shading on the peanut canopy, and nitrogenase activity of the peanut were measured. Averaged across corn spacings, intercropping reduced peanut yields by 44 and 64% in 1983 and 1984, respectively. Corn yields were not significantly affected by intercropping, but decreased linearly from 4.2 to 3.5 Mg ha−1 with decreased population density of corn. Conversely, peanut pod yield per hectare, pods per plant, and nitrogenase activity per plant increased linearly with decreased corn population density. Because of these countervailing trends, the combined yield and the land equivalency ratio (LER) (1.49 in 1983, a dry year, and 1.28 in 1984, a wetter year) of the intercrops were little affected by corn spacing. The 0.125‐m within‐row corn spacing resulted in the highest corn and combined dry seed yields, while the 0.335‐111 within‐row corn spacing resulted in the greatest combined economic value because of greater peanut yields. Peanut in monoculture gave the greatest economic value. This study pointed out that very low corn densities («30 000 plants ha−1) should be considered in peanut‐corn intercrops and that an LER >1.0 does not necessarily imply an economic advantage to intercropping.
Problems with Porometry: Measuring Net Photosynthesis by Leaf Chamber Techniques
Authors: Idso S. B. , Allen S. G. , Kimball B. A. , Choudhury B. J. 
Published: July 2010

AbstractPrior experiments with cotton (Gossypium hirsutum L.) and water hyacinth [Eichhornia crassipes (Mart.) Solms] demonstrated that porometer chamber conditions may significantly perturb the measurement of leaf stomatal conductance. Thus, this study was conducted to determine if net photosynthesis rate measurements of water hyacinth and cotton leaves were similarly perturbed by leaf chamber conditions and, if so, to devise a method to correct for the instrument‐induced error. Several net photosynthesis rate and concurrent canopy environmental data sets for these two plant species were analyzed at Phoenix, AZ within the context of the non‐water‐stressed baseline paradigm, which relates foliage‐to‐air temperature difference to air vapor pressure deficit. It was found that leaf chamber measurements of net photosynthesis rate were subject to the same type of measurement error as that associated with porometer measurements of leaf stomatal conductance. For plants transpiring at potential rates, photosynthesis rates can be corrected by using ancillary data obtained by the leaf chamber system. However, the proper adjustment of net photosynthesis rates of water‐stressed plants measured with leaf chambers required free‐air foliage and air temperatures, as well as the free‐air humidity. It was demonstrated that concurrent infrared radiation thermometry, as well as simultaneous measurements of air wet‐ and dry‐bulb temperatures, are required to correctly evaluate, by leaf chamber techniques, the net photosynthesis rates of plants that are experiencing any degree of stomatal closure due to some aspect of their normal environment.
Plant Nutrient Flow in the Managed Pathways of an Intensive Dairy Farm
Authors: Bacon S. C. , Lanyon L. E. , Schlauder R. M. 
Published: July 2010

AbstractThe magnitude, and spatial and temporal patterns of nutrient flow in the managed pathways of a farm are related to farm management decisions and interact with the biological processes of the farm. These descriptions of nutrient flow can be part of a nutrient management process that is consistent with the specifics of individual farm operations and particular farm performance goals. Nutrient flow in the managed pathways of a Pennsylvania dairy farm was measured at farm, field, and livestock unit boundaries using on‐farm equipment scales, farm records, and material sampling and analysis. Farm nutrient inputs of N, P, and K were twofold or more greater than outputs of these nutrients in the managed pathways. The temporal distribution of flows was closely related to the livestock activities on the farm. Manure storage capacity and crop developmental stage were significant factors influencing the timing of nutrient flows to and from the fields. Nutrient inputs and outputs in the managed flows at the boundary for the set of all fields were approximately equal except for the negative calculated crop available N balance. However, the range in balances for individual fields was large. Manure N and potential biological N fixation were not used efficiently on this farm due primarily to the volatilization of N from manure and the application of manure to alfalfa. Additions of nutrients to the farm in the managed flows decreased by 26, 60, and 43% for N, P, and K, respectively, in the 2nd yr of the study due primarily to less purchased animal feeds.
Pepper Transplant Response to Root Volume and Nutrition in the Nursery
Authors: Bar‐Tal A. , Bar‐Yosef B. , Kafkafi U. 
Published: July 2010

AbstractThe use of pepper (Capsicum annuum L.) seedlings for transplanting in the field is common. However, very little is known about the effects of root volume and nutrition in the nursery on transplant performance in the field. The objective of this work was to study the effects of N and P supply to various root volumes on pepper seedling development and growth in the nursery, and fruit yield and harvest earliness in the field. Seedlings were grown in trays packed with a peat/vermiculite mixture, 1:1 (v/v). The plants were irrigated by soaking the trays in the studied nutrient solutions. Phosphorus and N concentrations in the test solutions were 0.1, 0.5 and 1.0 mM P and 1, 5, 10 and 15 mM N (NH4/NO3 = 1:1). Root volumes (V) were 5, 15, 35, 65 and 700 cm3 plant−1. Following transplanting, all plants in the field received identical, optimal irrigation and fertilization. Seedling weight increased with increasing root volume and nutrient concentrations in the irrigation water. The optimal solution for pepper seedlings in the studied growth medium was 5 mM N and 0.5 mM P. Nitrogen, P and K contents in tops of optimal seedlings (V = 700 cm3) were 39, 5.5 and 67 g kg−1 dry matter, respectively. Seedling development was retarded when top's content was <25 mg N kg−1 and <3.1 mg P kg−1. Four weeks after transplanting plant weight in the field increased and fruit ripening was hastened when the top's dry weight at planting time increased from 63 to 285 mg plant−1. Plant relative growth rate and total fruit yield were unaffected by nursery treatments.
Root Quantification by Edge Discrimination Using a Desktop Scanner
Authors: Pan W. L. , Bolton R. P. 
Published: July 2010

AbstractRoot characterization methods are constrained by one or more of the following factors: cost, limited resolution, or time of analysis. Most length‐determination methods are based on the line‐intersect principle. An alternate method using a flatbed scanner and a microcomputer was developed. Algorithms were developed to estimate root area, length, and diameter (mean root width). Two‐dimensional area is estimated by summing the number of pixels representing a single or group of gray scales. Length and width are calculated as a function of the area, the number of edge pixels, and the number of pixels on diagonal edges. Human hair, plastic line, and root samples, with widths from 0.13 to 1.65 mm and lengths near 100 cm, were measured manually and with image analysis. Mean lengths of four repeated scans after reorientation were within 0.4 to 1.2% of manually determined lengths. Four repeated scans (118 pixels cm−1) of reoriented roots yielded length estimates with C.V.'s from 0.31 to 2.18% on low density samples (<500 cm). At higher densities, increased frequency of adjoining edges resulted in underestimated lengths and overestimated widths. A correction for these inaccuracies, based on the determination of mean width on a low density subsample, provided accurate root length estimates up to 10 m. Overall, this method overcomes limitations of other procedures such as (i) the requirement for random orientation of the sample necessary with the line‐intersect method, (ii) reliance on a comparison to a standard curve from non‐root objects, and (iii) inadequate imaging resolution.
Ear Position and Vertical Distribution of Leaf Area in Corn
Authors: Dwyer L.M. , Stewart D.W. , Hamilton R.I. , Houwing L. 
Published: July 2010

AbstractLeaf area distribution determines the interception of radiation for photosynthesis. A method of analysis was developed to quantifiy differences in vertical leaf area distribution in a corn (Zea mays L.) canopy. A third‐order polynomial accurately described the relationship between leaf area index (LAI) and plant height (both normalized with respect to their maxima) for a range of normal and “leafy” licensed and experimental plant lines during the late vegetative and early grainfilling stages (r2≥0.85). The shape of the polynomial reflected the bell shape of individual leaf area versus leaf number curves, with the densest leaf area in the mid‐portion of the canopy. When ear position was marked on the polynomial plot, the proportion of leaf area above the ear was easily compared among lines. The proportion of total LAI above the ear varied from 0.52 to 0.83 in 1986 and from 0.63 to 0.86 in 1987. The actual LAI above the ear was in a relatively narrow range of 2.0 to 3.2 for all tested licensed lines. The analysis described will facilitate comparison of ear position and vertical distribution of leaf area among different plant lines and crop management practices.
Soybean Planting Patterns in Relation to Yield and Yield Components
Authors: Ikeda T. 
Published: July 2010

AbstractResearch on the effect of soybean [Glycine max (L.) Merr.] planting patterns on yield have produced variable conclusions; some indicated that high yield was produced by equidistant patterns, but others indicated that clear differences in yield were not found. Therefore, the objective of this study was to determine whether different planting patterns effect soybean yield, and to determine which planting patterns produce the highest yield. These experiments were conducted in the field at Niigata University, Niigata, Japan for 3 yr on a loamy sand soil at a plant population of 25 plants/m2, using the cultivar Enrei (Group VII). Planting patterns varied across years and included wide rows (70 or 80 cm), square and rectangular patterns, and twin row arrangements with two narrow rows 10 or 20 cm apart with 50 or 60 cm between the twin rows. The results indicated that (i) yield tended to decrease with wider row widths and narrower within row spacings. Thus, it should be possible to increase yield with square patterns, (ii) A constant 70‐cm width with the twin‐zigzag patterns (plants in the twin rows offset from each other) yielded higher than twin‐rectangular ones (plants in the twin rows across from each other). In all cases, the increased yields came from an increase in seeds per plant; weight per seed was not affected.
Integrated Weed Management Techniques to Reduce Herbicide Inputs in Soybean
Authors: Buhler Douglas D. , Gunsolus Jeffrey L. , Ralston Donald F. 
Published: July 2010

AbstractInformation on integrated weed management systems is needed so that producers can develop systems that minimize the environmental impacts of weed control without sacrificing profitability of crop production. Reduced rates of broadcast‐ or band‐applied alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide] plus metribuzin [4‐amino‐6‐(1,1‐dimethylethyl)‐3‐(methylthio)‐1,2,4‐triazin‐5(4H)‐one] and rotary hoeing, each in combination with between‐row cultivation, were evaluated for weed control in soybean [Glycine max (L.) Merr.]. One or two between‐row cultivations allowed for a 50 to 75% reduction in the amount of herbicide used without reducing weed control or soybean yield. Reducing herbicide rates also decreased soybean injury. Two passes of a rotary hoe reduced weed densities up to 75% and increased the effectiveness of subsequent cultivations. However, two passes of the rotary hoe reduced soybean density as compared to other treatments. In 1989, under low weed densities, several mechanical weed control systems resulted in soybean yields similar to the weed‐free control. In 1990, under greater weed densities, mechanical weed control systems resulted in reduced soybean yields compared to weed control systems that included herbicides. Based on the results of this research, switching from chemical‐intensive systems to mechanical weed management systems under high weed pressure is not advisable. Under high weed pressure, reduced rates of herbicide, broadcasted or banded over the soybean row, in combination with cultivation provided excellent weed control. Mechanical weed control as a part of an integrated weed management system should maximize weed control while minimizing herbicide use.
Animal Preference of Tall Fescue during Reproductive Growth in the Spring
Authors: van Santen Edzard 
Published: July 2010

AbstractAnimal preference may create problems when diverse tall fescue (Festuca arundinacea Schreb.) germplasm is evaluated under grazing. The objective of this experiment was to relate differences in animal preference of tall fescue populations to maturity and genetic background. In 1988, 25 entries were established in small plots at the Black Belt Substation, Marion Junction, AL on a Eutaw clay (very‐fine, montmorillonitic, thermic, Entic Peluderts) within each of four 0.8‐ha pastures. Pastures were grazed during the spring 1990 and 1991 seasons at stocking rates of 2.5, 3.75, 5.0, and 6.25 crossbred yearling Angus steers ha±1 (Bos spp.). Animal preference was measured by visually rating the amount of forage removed at 3, 6, and 13 d after grazing was begun in 1990, and after 3 and 6 d in 1991. Population‐by‐stocking‐rate interaction was significant for all preference ratings, but accounted for only 2 to 5% of the total variation. Changes in magnitude were not important. Based on bivariate plots of preference during spring reproductive growth vs. maturity, three groups were distinguishable: (i) two very early maturing populations with a low preference score, (ii) a group of 17 medium‐maturing populations with a medium to low preference score, and (iii) six late maturing populations with a high preference score. Low preference during grazing of tall fescue during spring reproductive growth was an attribute of mediterranean germplasm and of populations selected in the southern USA. A comparison of ‘Georgia 5’ EI vs. EF tall fescue revealed that cattle preferred the endophyte free material at all rating times during reproductive growth in the spring in both years. This preference can be uniquely attributed to the absence of the endophytic fungus Acremonium coenophialum Morgan‐Jones and Gams.
Contribution of Bean Morphological Characteristics to Weed Suppression
Authors: Wortmann Charles S. 
Published: July 2010

AbstractWeed control has a high labor requirement in small‐scale bean (Phaseolus vulgaris L.) production systems in eastern Africa, and productivity of these systems often is constrained by labor availability at weeding times. This study was conducted to determine which morphological characteristics of bean contribute to weed suppression and to assess the feasibility of breeding genotypes for improved ability to suppress weeds. Morphological characteristics and grain yield of 16 to 20 bean genotypes, and weed biomass weight at harvest, were measured over three seasons. Mean weed biomass at time of bean harvest ranged from 55 to 120 g m−2 for the 15 genotypes evaluated for three seasons. The ability to suppress weeds was found to be independent of bean growth habit, but was related to leaf size, leaf area index, and plant growth rate. Leaf size and leaf area index accounted for 73% of the variation among genotypes for weed biomass at the time of bean harvest. These traits were related positively to bean seed yield. Inclusion of large leaf size and high leaf area index as criteria for selecting high‐yielding genotypes with improved ability to suppress weeds should be feasible.
Nitrogen Fertilization of Cotton Cultivars of Differing Maturity
Authors: McConnell J. Scott , Baker William H. , Miller David M. , Frizzell B. Stephen , Varvil J. Joseph 
Published: July 2010

AbstractManagement of N nutrition of cotton (Gossypium hirsutum L.) is one of the most critical aspects of successful cotton production, but growth and yield responses of individual cotton cultivars to N fertilization is relatively unknown. The objective of this research was to evaluate the responses of three cotton cultivars (Arkot 518, Stoneville 453, and Deltapine 90) to soil‐applied N fertilization rates. The study was conducted for 3 yr on a Hebert silt loam soil (fine‐silty, mixed, thermic Aeric Ochraqualf). Few significant (ɑ = 0.05) cultivar × N rate interaction differences were found, although main effects of the N treatments and the cultivars were evident. The most pronounced responses of the cotton were found as an effect of the N‐fertilization treatments. Nitrogen rates in excess of 112 kg N ha−1 did not significantly increase seed cotton yields in any year of the study. The mean yield of the cultivars among N rates was significantly different in only one year of the study. Earliness of the cotton was reduced by increasing N rate, as indicated by significant differences in nodes above white flower (NAWF) measurements. Significant differences were also found in the NAWF measurements for the cultivars, thereby inferring maturity differences among the cultivars tested. Of the cultivars evaluated, Arkot 518 was earliest, followed by Stoneville 453, and then Deltapine 90. Significant interactions of cultivar and N rate were found only in three dates of NAWF (1991), and one date of petiole NO‐3‐N content (1990). Soil samples taken after 3 yr of continuous fertilization treatments showed a significant NO‐3‐N accumulation at the 15‐ to 45‐cm depth only in plots treated with 224 kg N ha−1.