bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Five Food Legume Crops to an Irrigation Gradient Imposed During Reproductive Growth
Authors: Senthong Chuckree , Pandey R. K.
Published: July 2010

Food legumes, an excellent source of protein and soil fertility improvement, offer small farmers a means of intensifying cropping on rice lands in semiarid and tropical regions. Unfortunately food legume productivity is often limited by variation in the amount and distribution of rainfall. The study was conducted to compare differential responses of mungbean (Vigna radiata L.), soybean [Glycine max (L.) Merr.], cowpea [Vigna unguiculata (L.) Walp.], peanut (Arachis hypogaea L.), and pigeonpea (Cajanus cajan L.) to a soil water gradient imposed during the reproductive growth phase. Field studies were conducted on Lipa clay loam, an isohyperthemic Typic Hapludoll silt loam soil, using a line source sprinkler irrigation system at the International Rice Research Institute, Philippines, from January to May during 1985 and 1986. Among the five species, peanut yielded significantly higher across the irrigation regimes in both years. Lack of water in the driest regime (50% water deficit replacement) reduced the seed yield of mungbean, soybean, cowpea, and peanut by an average of 43, 39,34, and 32%, respectively. However, pigeonpea seed yield increased by an average of 31% in the driest regime. Seed yield increases per mm of total irrigation water plus rainfall were 3.46 and 5.61 kg ha−1 in soybean, and 3.55 to 5.67 kg ha−1 in peanut in 1985 and 1986, respectively. However, pigeonpea yield per mm of total irrigation water plus rainfall declined 1.53 and 1.27 kg ha−1 in 1985 and 1986, respectively. Peanut performed best in irrigated as well as in rainfed environments, followed by cowpea, soybean, and mungbean. Pigeonpea was suitable only for the relatively dry, rainfed environment. Results indicate the need to match the suitable food legumes to maximize the rice land use.
Apparent Recovery and Physiological Efficiency of Nitrogen in Sesbania Incorporated before Rice
Authors: Furoc R. E. , Morris R. A.
Published: July 2010

When incorporated for lowland rice (Oryza sativa L.), the agronomic efficiency of green manure N exceeding 100 kg ha−1 is low. Apparent N recovery and physiological efficiency of green manure N, ranging to 200 kg N ha−1 were determined on a fine, mixed, isohyperthermic Aerie Tropaqualf in the Philippines. Sesbania sp. accumulated 100 kg N ha−1 in 48 d and 160 kg N ha−1 in 60 d. Nitrogen uptake (NU, kg N ha−1) from green manures flooded during the last 25 d before incorporation was a linear function of incorporated N (NU = 49 + 0.23N). Uptake from green manures that were not flooded diminished as incorporated N increased (NU = 35 + 0.51N – 0.0012N2). The flooding effect was attributed to inhibition of NO−3 accumulation on submerged control plots. Nitrogen uptake was linearly related to extractable NH+4‐N determined 7 d after green manure incorporation. As N uptake increased, however, physiological efficiency declined. Dry‐season rice recovered only 6% of the green manure N not recovered by wet‐season rice. Because both apparent recovery and physiological efficiency are low, and residual green manure N recovery is minor, the advantage to growing Sesbania sp. for more than 48 d to accumulate N in excess of 100 kg ha−1 is limited.
Image Analysis Morphometric Measurement for Tissue Water Status and Other Determinations
Authors: Spomer L. Art , Smith M. A. L.
Published: July 2010

Agronomic research often requires observations involving accurate quantification of plant morphometric properties. Conventional methods are usually burdensome and often inaccurate, especially when features of interest are irregular in shape. A video image analysis system capable of accomplishing rapid and accurate morphometric measurements was demonstrated. The degree of shrinking or swelling of leaf disks was determined of chrysanthemum (Chrysanthemum morifolium Ramat.), soybean [Glycine max (L.) Merr.], and pothos (Epipremnum aureum) in an isopiestic evaluation of tissue water status. This image analysis setup, with a potential resolution of 2.357 ✕ 10−6 cm2, rapidly (about 20 s) resolved minute disk area changes within a range of 0.2463 to 0.2827 cm2, with a maximum deviation of 1.5 X 10−4 cm2 (approximately 0.057% of disk total area). Microcomputerized video image analysis is concluded to be a valuable tool for achieving previously impossible or difficult morphometric measurements in a wide range of experiments.
Interfacing an Electronic Analytical Balance with a Microcomputer to Facilitate Gravimetric Laboratory Analyses
Authors: Gates R. N. , Waller S. S. , Lawrence B. K. , Mullahey J. J.
Published: July 2010

A program is described that reduces laboratory time and labor by using an interface card to input readings from an electronic analytical balance to a microcomputer. Use of the system and the program is illustrated for detergent fiber analyses of forage samples. The program automatically records balance readings and calculates analytical results. Results are stored on floppy disks. Advantages include reduced time input for repetitive weighings and elimination of errors resulting from transcription or calculation. Results may also be transferred directly to another computer for summarization and statistical analyses.
Agronomic Performance of Sugary‐Brawn2 Maize: A Potential Additive for High‐Protein Silage Production
Authors: Tracy W. F. , Coors J. G.
Published: July 2010

Alfalfa (Medicago sativa L.) is low in soluble carbohydrates, which are required for successful silage preservation. Storing alfalfa as silage could reduce quality losses due to weathering, however. Adding grain high in soluble carbohydrates, such as sugary‐Brawn2 (su‐Bn2) endosperm maize (Zea mays L.), improves silage preservation, and results in higher quality feed. However, certain endosperm mutants, including alleles at the sugary locus, have been shown to reduce grain yields, dry matter production, and possibly photosynthetic rates. Our objective was to determine if su‐Bn2 maize hybrids have acceptable yield, ear moisture levels, and stalk and root quality for on‐farm grain production in the northern Corn Belt. Twenty su‐Bn2 hybrids and two adapted dent hybrids were grown at three locations in Wisconsin in 1986 and 1987. Data were collected on ear yield, ear moisture, heat units to midpollen and midsilk, plant and ear height, and root and stalk lodging. Yield of the su‐Bn2 hybrids ranged from 7.26 to 9.41 Mg ha−1, as compared with 7.96 and 9.40 Mg ha−1, for the two checks. Ear moisture of the su‐Bn2 hybrids was higher than that of the checks, although a number of su‐Bn2 hybrids had acceptable moisture levels. The su‐Bn2 hybrids compared favorably with the checks for plant and ear height, and stalk and root lodging. Maize with su‐Bn2 endosperm can be grown successfully in the northern Corn Belt for use as an additive in the ensiling of alfalfa. Management practices and economic aspects need to be further investigated.
Growth‐Promoting Activity of Chlordimeform
Authors: Bauer P. J. , Cothren J. T.
Published: July 2010

Early season applications of the insecticide chlordimeform [N' ‐ (4‐chloro‐o‐tolyl)‐N,N‐dimethylformamidine] (CDF), have increased cotton (Gossypium hirsutum L.) lint yields above those expected from the pesticidal properties of the chemical. The molecular structure of CDF resembles other agricultural chemicals that have cytokinin‐like activity. The objective of this research was to determine whether CDF possesses biological activity similar to these compounds. Chlordimeform was compared with the naturally occurring cytokinin zeatin in two hormone bioassays (radish [Raphanus sativa L.] cotyledon expansion and cytokinin‐depleted soybean [Glycine max L.] callus growth). Chlordimeform induced radish cotyledon expansion when the cotyledons were incubated under continuous light. The optimal CDF concentration for cotyledon growth was 5.1 ✕ 10−4 M. Although expansion occurred under light conditions, CDF inhibited chlorophyll synthesis at the higher concentrations and did not induce growth when cotyledons were incubated in the dark. These responses were contrary to the response of cotyledons incubated with zeatin. Also, no activity was found in soybean callus culture. The data suggested that CDF has plant physiological activity, but the biological activity is not identical to that of zeatin.
Fallow Management Practices for Wheat Production in the Central Great Plains
Authors: Smika D. E.
Published: July 2010

Information comparing reduced and no‐till fallow management practices to conventional stubble mulch fallow for wheat production in a wheat‐fallow rotation in the semiarid Central Great Plains is limited. A 12‐yr study conducted at the Central Great Plains Research Station near Akron, CO evaluated the following seven soil management practices for their effectiveness for promoting soil water storage, reducing soil erosion potential, maintaining soil nutrient availability, and increasing winter wheat (Triticum aestivum L.) production and quality: (i) conventional stubble mulch tillage; three practices where weed control was achieved with herbicides except for (ii) one tillage operation performed as needed for weed control in early spring, (iii) immediately after harvest, and (iv) late fall (October); (v) chemical weed control except for one tillage after harvest and one tillage the following summer; (vi) chemical weed control with three tillage operations just prior to wheat seeding; (vii) and no‐till, all weed control achieved with herbicides. Nitrogen fertilizer as urea‐ammonium nitrate (UAN) was applied to all practices at the end of each fallow period at 56 kg ha−1. The soil at the research site is a montmorillonitic, mesic Aridic Paleustoll. No‐till consistently produced 10% more grain, had 9% higher soil water storage efficiency, and 7% fewer erodible‐sized soil particles than conventional tillage. The NO3‐N availability was comparable for all practices. The reduced‐tillage practices fell between the no‐till and conventional tillage extremes and varied with year‐to‐year climatic differences.
Nitrogen Contamination of Soils from Sampling Bags
Authors: Kitchen N. R. , Sherrod L. A. , Wood C. W. , Peterson G. A. , Westfall D. G
Published: July 2010

Soil samples can be contaminated with N by storage in bags described by the manufacturer to contain a wax laminated glassine liner (WLG). This study was conducted to compare samples stored in a WLG sample bag and a polyethylene bag (POLY). Sandy and clay loam soils were brought to three different moisture contents representing wet, moist, and dry, approximately 0.20,0.06, and 0.01 kg H20 kg−1 soil, respectively, and stored in the WLG and POLY sample bags for 12, 48, and 120 h. Sample bags and soils were extracted for NH4−N and NO3−N with 2 M KCI. Extraction of shredded WLG and POLY bags gave 189.4 and 1.7 mg NH4−N kg−1 bag, and 12.5 and 0.3 mg N03−N kg−1 bag, respectively. Ammonium‐N concentration increased in both soils (from 4–42 mg N kg−1 soil) when stored either moist or wet in the WLG bag. The moist clay loam and the wet sandy loam increased 9 and 15 mg NO3–N kg−1 soil, respectively, when stored in the WLG bag for 120 h. The WLG bag should not be used for soil samples. All bags should be checked for N contamination prior to use.
Chromaticity Parameters in Relation to Visual Grades of the Flue‐Cured Tobacco
Authors: Carotenuto R. , Troncone R. , Martiniello P.
Published: July 2010

The quality of flue‐cured tobacco (Nicotiana tabacum L.) depends on field‐growth conditions and post‐harvest processing, and can be partially determined by the color of the leaves. The objectivesof the investigation were to determine the range of values of chromaticity parameters of visually graded leaves and to evaluate the possibility of utilizing the parameters for electronic screening. The classification of leaves (visually or mechanically) is generally based on the evaluation of chromaticity differences of their color. The success of electronic screening requires an accurate definition of the chromaticity parameters a*, b*, and L*, which were defined mathematically by the International Commission on Illumination. Ten common tobacco cultivars were grown in each of 2 yr. The leaves were harvested four rewings and separated into bottom, lower, upper middle, and top leaves. After flue‐curinp, an adequate sample of leaves from each harvest was visually classified into three merit‐classes (grade A, B, and C). A colorimeter was used to determine the chromaticity parameters. Leaves from different cultivars and leaf positions on the stalk differed in grades and chromaticity parameters. The cluster technique of the L*, a*, and b* values defined for each merit‐class provided a range of chromaticity parameters that can be successfully utilized in electronic screening processing. Four cluster groups for chromaticity parameters L* and a*, and five for b*, were obtained. The range of values of the chromaticity parameters (L*, a*, and b*) obtained from the cluster method were correlated with the grades visually selected.
Fine Root Development of Alfalfa as Affected by Wheel Traffic
Authors: Rechel E. A. , Meek B. D. , DeTar W. R. , Carter L. M.
Published: July 2010

Root development in alfalfa (Medicago sativa L.) is dependent of many factors including the soil environment which is influenced by crop management procedures. Soil compaction, which is unavoidable under current management procedures, can have a detrimental effect on root development. The purpose of this field experiment was to compare the effects of controlled and conventional traffic management on alfalfa fine root growth in a Wasco sandy loam (coarse‐loamy, mixed, nonacid thermic Typic Torriorthent). No wheel traffic and traffic only before planting were compared to two conventional systems that varied in the amount of traffic applied during crop production. Twenty months after planting, there was a significant decrease in fine root density (FRD) from single passes of traffic after each harvest down to a 0.45‐m depth while several passes after each harvest significantly decreased FRD down to 1.8‐m depth. Regardless of treatment, root density was greatest in the upper 0.1 m of soil decreasing to 1.8 m in the first summer. By the second summer FRD showed bimodal distribution with significantly fewer roots at 0.3 to 0.6 m compared to layers above and below this depth. Seasonally there was a significantly higher root density during the winter than the summer in the upper 0.3 m of soil. The results of this study shows that alfalfa fine roots more thoroughly exploit the soil volume in the absence of wheel traffic and that compaction from traffic diminished root growth to different depths depending on its intensity.
Management Effects on Harvest Losses and Yield of Double‐Crop Soybean
Authors: Grabau L. J. , Pfeiffer T. W.
Published: July 2010

Soybean [Glycine max (L.) Merr.] double cropped with wheat [Triticum aestivum (L.) em Thell] may be more subject to harvest losses than a full season crop due to reduced lowest pod height (LPH). The objective of this field study was to determine the effects of wheat stubble heights (WSH) of 0,15, and 30 cm; soybean planting rates of 37, 65, and 92 seeds m−2; and soybean cultivars of differing maturity [Pella, early Maturity Group (MG) III, Douglas, mid‐MG IV, and Mitchell 450, late MG IV] on LPH, harvest losses, and yield. Clipped wheat residues were removed, and soybean planting was done without tillage on a Maury slit loam (Typic Paleudalfs). Increases in WSH and soybean planting rate had no effect on soybean harvest losses, which averaged 0.4, 2.0, and 6.6% for soybean cutting heights (SCH) of 5, 10, and 15 cm, respectively, and reached 16.5% at the 15 cm SCH for Pella in 1986. The latest maturing cultivar had the highest LPH and incurred the smallest harvest losses. Its yield performance in these years, however, was not competitive with the earlier maturing cultivars (2.06, 2.03, and 1.72 Mg ha−1 for Pella, Douglas, and Mitchell 450, respectively). Increasing WSH from 0 to 15 cm improved mean soybean yield by 16.9% in 1986, but had no effect in 1985. Although the use of a later maturing cultivar resulted in greater LPH, its yield was less than earlier cultivars. Increased WSH and soybean planting rate were not supported as strategies to reduce soybean harvest losses.
Herbage Production: Conventional Mixtures vs. Alternating Strips of Grass and Legume
Authors: Fairey N.A. , Lefkovitch L.P.
Published: July 2010

Soil N influences the agronomic characteristics of grass‐legume herbage. A conventional grass‐legume stand was compared for productivity, quality, and botanical composition, at two locations for three production years, to three stands comprised of alternating, broadcast‐seeded strips (40‐, 60‐, or 80‐cm width) of pure grass and pure legume. Stands were of smooth bromegrass (Bromus inermis Leyss.) and alfalfa (Medicago sativa L.), and were grown under three N fertilizer treatments: N0 = no N; NGL = 150 kg ha−1 N applied uniformly to grass and legume; and NG = 150 kg ha−1 N but with the distribution of N restricted to plot areas seeded to grass. Grass dry matter (DM) yield declined as strip width increased with N0 (1.80‐0.92 t ha−1) and NGL (3.67−2.56 t ha−1), but was unaffected by strip width with NG (3.60 t ha−1). Herbage DM digestibility was 698, 699, and 708 g kg−1 for the 40‐, 60‐, and 80‐cm strip‐culture stands, respectively, and 690 g kg−1 for the conventional mixture. Legume concentration in harvested herbage (DM basis) ranged from 726 to 798, 489 to 524, and 411 to 426 g kg−1 for the strip‐culture stands with N0, NGL, and NG, respectively; it was 658 and 375 g kg−1 for the conventional mixture with N0 and NGL, respectively. Strip‐culture stands have potential for manipulating grass/legume ratios of herbage, and may provide a way to supply optimal N fertilizer to grass plants in grass‐legume associations, without relinquishing the N‐fixing contribution of the legume.
Seeding Density and Row Spacing for Lentil in Rainfed Mediterranean Environments
Authors: Silim S. N. , Saxena M. C. , Erskine W.
Published: July 2010

Lentil (Lens culinaris Med.) is largely sown by hand broadcasting at around 400 seeds m−2 in West Asia. Rising labor costs for hand harvest are forcing farmers to consider machine harvesting, which is economically feasible only on mechanically drilled, flat seedbeds. Seeding experiments were conducted at three sites between 1979 and 1986 to determine the effect of seeding densities (100–400 seeds m−2) and row spacing (0.2,0.3,0.4, and 0.5 m) on the seed yield, biological yield and economic return of rainfed lentil. The main site, Tel Hadya (Syria) had a mean annual rainfall of 315 mm over five seasons; Terbol (Lebanon) was wetter with 520 mm over two seasons; and Breda (Syria) was drier with 244 mm over two seasons. Seed yield and total biological yield were greater at the two wetter sites, but yields were significantly affected by seeding density within each site. The relationship between yield and seed density was best described by a quadratic curve. At the wetter sites (Tel Hadya and Terbol), seeding densities for maximum seed yield were 267 ± 33 seeds m−2, considerably lower than the 334 ± 4 at the drier Breda site. for maximum total biological yield, the seeding densities were 276 ? 22 for Tel Hadya, 298 ± 16 for Terbol, and 346 ± 4 seeds m−2 for Breda. The results indicated that using a seed drill, the optimum density for gross economic return minus seed cost was 280 seeds m− at Tel Hadya and Terbol and 320 seeds m−2 at Breda. These rates represent a potential saving in seed costs of 20 to 30% over hand broadcasting. Yields were less responsive to row spacing than to seeding density. Narrowest row spacing (0.2 m) generally gave the greatest seed yields, which decreased linearly with increased row spacing.
Experimental Design and Data Management of Rotation Experiments
Authors: Cady Foster B.
Published: July 2010

Well summarized data from long‐term cropping systems experiments give agriculturists and others direction for improving and sustaining crop productivity in a cost‐effective manner while recognizing environmental concerns. Long‐term agronomic studies range from a few demonstration plots to multisite, replicated and randomized trials with complex experimental and treatment designs. Basic design principles need to be used with additional requirements, e.g., each phase of each cropping sequence should occur each year. Data management becomes more complex as multiple crop‐soil variables are measured over time. The multiyear data must be stored efficiently and must be easily retrievable to users with varied uses. Analysisof‐variance procedures are relevant for evaluation of interactions and are followed by specialized modeling applications. The commonly held statistical assumptions of experimental error for annual experiments may not be valid in long‐term studies where yields are measured on the same plots over years. Selection of an analysis approach depends on the assumed error structure. The renewed interest in existing long‐term studies encourages innovative approaches to data management, graphics and experimental modeling. The challenge is to make summarized data, including means, other model estimates and standard errors, accessible to users in a format that answers their questions.
Interaction of Salinity and Temperature on the Germination of Crambe
Authors: Fowler J.L.
Published: July 2010

Crambe (Crambe abyssinica Hochst. ex R.E. Fries) is a potential oilseed crop for semiarid and arid environments where saline irrigation waters and soils are common. Crambe tolerance to salinity during germination is unknown. A laboratory experiment was designed to determine salinity tolerance of crambe during germination and salinity ✕ temperature interactions that may influence germination and stand establishment. Treatment solutions were prepared using NaCl and CaCl2 in a 2:1 molar ratio. Salinity (electrical conductivities of 0.03, 6.3, 12.1, 17.3, 22.5, 27.1, 32.0 and 36.3 dS m−1) and temperature (5, 10, 15, 20, 25 and 30 °C) effects on germination of ‘Meyer’ crambe seed were determined over a 12 d period. Counts were taken at 3 d intervals and germination percentages and rate indexes were determined. Germination declined with increasing salinity at each counting date and salinity ✕ temperature interactions were highly significant. Germination was severely limited at 5 °C with only 22% germination in the salinity control (0.03 dS m−1) after 12 d. The optimum germination temperature for all salinity levels fell in the 15 to 25 °C range, with the final cumulative germination percentage peaking at 20 °C for most treatments. Germination decreased on either side (10 and 30 °C) of the optimum. Germination rate was drastically reduced at 5 °C at all salinity levels, with an intermediate effect at 10 and 30 °C at the lower salinity levels decreasing with increasing salinity at all temperatures. These results suggest that crambe is moderately tolerant to salinity stress during germination over the 10 to 30 °C temperature range.
Shoot Growth, Root Length Density, and Water Use of Barley Grown at Different Soil Temperatures
Authors: Sharratt B. S.
Published: July 2010

Temperatures considered optimum for root growth only occur near the soil surface in interior Alaska, and current literature inadequately describes low soil temperature (i.e. 5 °C) effects on plant development. This study determined shoot and root characteristics of barley (Hordeum vulgare L.) when grown at varying root zone temperatures (RZT). Leaf area, number of leaves and stems, and aerial and root biomass were assessed at heading of barley grown in pots in a glasshouse at RZT of 5, 10, and 15 °C. Plant stage and height were recorded twice weekly. Pots were sectioned at 5 and 10 cm below the soil surface to obtain root lengths and dry weights. Three replications of the experiment used sand as the soil media, a fourth replication used a soil/peat mixture. Plant water use was determined by subtracting the amount of water leached through pots from that added. Plants grown at 5 °C RZT had a 30% slower leaf appearance rate, 50% fewer stems and leaves, and 70% less leaf area than grown at 15 °C. Root length density increased with increasing RZT. Water use and water‐use efficiency were least at 5 °C RZT. Greater specific leaf weights at 5 °C RZT indicated greater photosynthetic efficiency, but reduced water uptake resulted in less dry matter production than at 15 °C RZT.
Persistence of Sainfoin under Different Grazing Regimes
Authors: Mowrey D. P. , Matches A. G.
Published: July 2010

Sainfoin (Onobrychis viciaefolia Scop.), a non‐bloat inducing legume, is well adapted to the calcareous soils of the Southern Great Plains. Poor persistence under some managements has limited its; use for grazing. Our objectives were to determine the effect of plant growth stage at defoliation and defoliation intensity on persistence of sainfoin. Nitrogen fertillized (100 kg N ha−1) ‘Renumex’ sainfoin was grown under irrigation on a Pullman clay loam (fine, mixed, thermic Torretic Paleustolll) near Lubbock, TX. Light (L), medium (M), and heavy (H) grazing intensities were applied at the bud (B), flower (F), and seed shatter (S) stages of growth. Across growth stages, L, M, and H intensities averaged 52, 69, and 87% removal of pre‐graze herbage mass, respectively. Over the 2 yr, sainfoin stands declined 20 and 43% when defoliated at the B and F stages under H defoliation intensity. Stands remained above 80% for the L and M intensities. Stands increased from reseeding in the S treatments by 35, 31, and 16% for the L, M, and H defoliations, respectively. Root concentrations of total nonstructural carbohydrates (TNC) began to decrease with the initiation of spring growth reached their seasonal low in June, and then increased into late summer and autumn. Average TNC for H (130 g kg−1) was less than TNC in roots of L and M (155 g kg−1). Our findings indicate thaf sainfoin defoliated at the B or F stages of growth under L or M intensities of defoliation may have acceptable stand persistence when grown under irrigation in the Southern Great Plains.
SUNLIGHT, A Program to Calculate Sunshine Duration Parameters for Evapotranspiration Models
Authors: Troyo‐Diéguez Enrique
Published: July 2010

The program, SUNLIGHT, was designed and developed to determine the theoretical sunshine duration and related parameters needed to estimate evapotranspiration of crops by means of solar radiation equations. The software was written in Gw‐Basic Version 2.02 to be used in a PC‐DOS compatible environment. Inputs required are the latitude of the site, in degrees, and a selected period of time. Outputs are (i) mean solar declination for the period, (ii) mean value of the cosin magnitude of the sun declination parameter, (iii) average sunshine duration in light‐hours per day, (iv) parameter percent of the number of light‐hours per day related to annual total, (v) sunshine duration expressed as the total number of light‐hours for the given period, and (vi) percent of light‐hours for the study period related to the annual total.
Increase in Drought Resistance of Cotton Seedlings Treated with Mepiquat Chloride
Authors: Xu X. , Taylor H. M.
Published: July 2010

Under rainfed conditions, plant establishment is often low in cotton (Gossypium hirsutum L.) because of water limitations. Increasing drought resistance of cotton seedlings by accelerating root growth thus has important, practical implications. Much research has been devoted to modifying plant root systems for more effective use of soil water, but successful results are few. We studied the effects of mepiquat chloride (MC; 1,1‐dimethylpiperidinium chloride) on drought resistance of cotton seedlings. Well‐watered seedlings were irrigated with mepiquat chloride (0‐40 mg kg−1), and then subjected to progressively greater water stress. Treatment with MC accelerated root growth and increased water absorption, especially at greater soil depths. The seedlings treated with MC were turgid longer and wilted less than the drought controls. In another series of experiments seeds were treated (0‐4000 mg kg−1) and arising plants were assessed for growth and survival in both well‐watered and water‐stress conditions. A seed treatment of 500 mg kg−1 gave shorter and more compact shoots, did not affect leaf area, but increased specific leaf weight and chlorophyll content. Seed treatment with 500 mg kg−1 MC also gave the greatest enhancement of root growth, water extraction from deep soil layers, and survival of stressed seedlings. These results suggested a potential for using MC to modify root patterns and increase drought resistance of cotton seedlings. Field tests of seed treatments with MC should be conducted to determine whether seedling survival is enhanced under natural drought‐stressed conditions. The responses of different cotton varieties to MC treatment also should be investigated.
Cellulase Solution Concentrations Used to Develop Spectral Equations for Predicting Tall Fescue Digestibility
Authors: Bughrara S. S. , Sleper D. A. , Roberts C. A.
Published: July 2010

Digestibility estimates obtained with prepared cellulase solutions and near infrared spectrophotometry (NIRS) have become valuable and reliable tools for forage quality determination. The objective of this study was to determine the optimum concentration of a prepared cellulase solution from a commercial source to obtain meaningful estimates of in vitro dry matter digestibility (IVDMD) and development of NIRS equations for tall fescue (Festuca arundinacea Schreb.). A total of 176 tall fescue samples were pretreated using pepsin and 0.125 M L−1 HCI followed by digestion using five different concentrations of a prepared cellulase solution obtained from Worthington Corp., Freehold, NJ. Concentrations of the prepared cellulase solution were 0.0, 0.2, 0.4, 0.6, and 0.8 g L−1. Maximum digestion occurred with the prepared cellulase solution at 0.57 g L−1. However, the most meaningful equation for estimating tall fescue IVDMD by NIRS occurred when samples were digested using the prepared cellulase solution at a concentration of 0.8 g L−1.
Corn Motion in the Wind During Senescence: I. Motion Characteristics
Authors: Flesch T. K. , Grant R. H.
Published: July 2010

Lodging in corn (Zea mays L.) is often the result of wind‐induced motion, which creates a strain on the stalk and root system. A study was conducted to characterize corn motion during windy periods at senescence and examine the implications for lodging. Motion was measured on 23 plants with a modified computer joystick during 6 d in October, 1988, at West Lafayette, IN. The wind force on each plant was estimated from within‐canopy wind speeds, foliage area distribution, and foliage drag coefficients. Results showed that corn stalk displacement during windy periods was variable over time. The displacement pattern was distinct from the wind force pattern, and characterized by a resonant oscillation at a frequency near 1 Hz. Generally there was greater displacement in the across‐row direction than in the along‐row direction, with the across‐row displacement variance more than four times larger than the along‐row variance. There was little effect of wind direction on motion characteristics. In addition, there was a decrease in maximum displacements and the amplitude of resonant oscillation when the ear fell from an upright position to a hanging position. The nature of the corn motion suggests that dynamic plant motion characteristics may be important in determining lodging resistance.
Alfalfa Yield Component Responses to Seeding Rate Several Years after Establishment
Authors: Kephart Kevin D. , Twidwell E. K. , Bortnem R. , Boe A.
Published: July 2010

Little information is available regarding the relationships of alfalfa (Medicago sativa L.) forage yield with yield components in seed‐established stands grown under dryland conditions. Field experiments that included two cultivars and 15 seeding rates ranging from m 2.2 to 33.6 kg pure live seed ha−1 were established in 1985 at Brookings and Highmore, SD. The objective was to determine seeding rate effects on components of alfalfa forage yield and on plant morphology several years after establishment. In the seeding year, plant density increased linearly with seeding rate at both locations. Yield components were determined in 1988 and 1989. Mean alfalfa yield during 1988 and 1989 was optimum at the 13.4 kg pure live seed ha−1 rate at Brookings, but did not respond to seeding rate at Highmore. Plant density continued to be affected by seeding rate 4 yr after establishment, but greater mortality at high seeding rates caused the response to deviate from linearity. Shoots per plant were negatively correlated with plant density (r = –0.73, P = 0.01). Shoot weight did not respond to seeding rate at Brookings but declined linearly with seeding rate at Highmore. Nevertheless, path analysis suggested that shoot weight was the major influence on alfalfa yield at both locations. Leaf‐to‐stem ratio and shoot length were not affected by seeding rate. Alfalfa yield components are affected similarly by plant density in seed‐established and transplanted stands. Although yield may not be affected by plant density, shoot weight may be affected because of differences in plant competition.
Big Bluestem and Switchgrass Establishment as Influenced by Seed Priming
Authors: Beckman Jana J. , Moser Lowell E. , Kubik Keith , Waller Steven S.
Published: July 2010

Seed dormancy and slow seedling development often limit establishment of warm‐season grass stands. Establishment of seedlings with two solid matrix seed priming (SMP) treatments [2‐d moistened (17°C) and 14‐d wet‐chill (4°C)] was compared with untreated seed of ‘Kaw’ and ‘Pawnee’ big bluestem (Andropogon gerardii Vitman) and ‘Path‐finder’ and ‘Cave‐in‐Rock’ switchgrass (Panicum virgatum L.) in greehouse and field experiments. In two greenhouse studies, seedling emergence was monitored from 7 to 26 d after planting and number of adventitious roots were monitored from 2 to 5 wk after planting. Field experiments were initiated on 19 Apr. 1988, 3 June 1988, and 23 May 1989, on a Sharpsburg silty clay loam (fine montmorillonitic, mesic, Typic Argiudolls). In the greenhouse, SMP treatments increased big bluestem emergency by 18%. In the field, final seedling emergency from dry untreated big bluestem seed was equal to or higher than that of SMP‐treated seed. The SMP treatments had no effect on adventitious root formation for big bluestem in either greenhouse or field experiments. In the greenhouse, the moistened and wetchill treatments increased seedling emergency of switchgrass 35 and 150%, respectively. In the greenhouse, SMP treatments slightly increased the percentage of switchgrass plants with adventitious root development 5 wk after planting but not in the field studies. Number of adventitious roots per plant were unaffected by treatment. In the field, the SMP‐treated seed produced the highest seedling emergence for switchgrass under moist planting conditions and had the potential to improve stands when seed was planted without drying. However, final seedling emergence from dry untreated seed was greater than that for SMP‐treated seed under dry soil conditions.
Soybean Yield Interaction between Helicoverpa zea Infestation and Simulated Frost Injury
Authors: Eckel Craig S. , Bradley J. R. , Van Duyn John W.
Published: July 2010

Soybean, Glycine max (L.) Merr., yields may be reduced by corn earworm, Helicoverpa zea (Boddie), feeding and by early frosts. One consequence of H. zea feeding can be a delay in pod development. A consequence of frost injury can be shortening of the seed fill duration. The objective of 12 experiments conducted at multiple locations from 1984 to 1987 was to evaluate the potential for an interaction between H. zea feeding damage and early frost. Insecticides were used to establish varying levels of H. zea populations in soybean and paraquat (1,1′.dimethyl‐4,4′‐bipyridinium dichloride) was used to simulate frost injury. Significant yield differences between levels of H. zea populations were detected in eight experiments, and paraquat treatments significantly reduced yields in 11 experiments. A significant interaction between H. zea population level and paraquat treatment time occurred in three experiments. In these experiments, yield reduction due to paraquat was greater where H. zea populations were larger. Although soybean can compensate for a delay in pod set caused by H. zea feeding in most years, when seed fill period is shortened, as would occur with early frost, a delay in pod set can contribute to yield loss. Identifying one of the many factors that lead to variation in yield loss from a particular level of H. zea infestation, is a step towards more effective management of this pest.
Differences in Response to Available Phosphorus among White Clover Cultivars
Authors: Gourley C. J. P. , Allan D. L. , Russelle M. P.
Published: July 2010

The selection of agriculturally important plant germplasms more tolerant of low P may increase productivity on P deficient soils and reduce P fertilizer requirements. Differences in response to P availability among six cultivars of white clover (Trifolium repens L.) were investigated in a series of pot experiments using a sand‐alumina culture technique and two low P soils, an acid Hapludult with 2.6 mg Bray‐P kg−1 and a calcareous Calciaquoll with 6.9 mg NaHCO3‐extractable P kg−1. Plants were grown in the greenhouse or growth chamber for up to 63 d in solution [P] of 0 to 82 μM. Plant characteristics measured included dry mass and P concentration of shoots, coarse roots, and fine roots; P distribution within the plant; and root traits of total length, root hair length and number per unit root surface area, and root tip number. There were significant differences in shoot dry mass and P accumulation response curves among cultivars; cultivar rankings were consistent in sand‐alumina and in soils, but differed from other reports in the literature. We found significant cultivarby‐solution [P] interactions when only low vs. high P availabilities were compared, but not when response curves were generated and compared. Differences in herbage yield and P accumulation were associated with larger root systems, but there was no evidence of greater efficiency of P uptake or utilization in these cultivars.
Potential Economic Benefits of Modifications to Urea That Increase Yield through Reduction in Nitrogen Losses
Authors: Buresh R. J. , Baanante C. A.
Published: July 2010

Many modifications to urea such as inhibitors, algicides, soluble salts, and acidifying agents have been proposed to overcome losses of urea‐N, but little is known about the potential economic benefits and acceptable farm‐level prices for modified urea. The objective of this study was to develop and use a method for estimating the potential economic benefits of modifications to urea that reduce N losses and enhance crop yields. The method is applicable for crops with a response to N that is well represented by a quadratic model, and for modifications to urea that do not alter the maximum attainable yield with added N. The increment in profit of farmers with the use of modified urea is determined by the difference in net benefit between modified urea and conventional urea when these fertilizers are used at rates that maximize profit. The increment in profit with modified urea increased linearly with increasing saving of N from loss, decreased with the increasing cost of modifying urea, and increased as the price of conventional urea‐N increased. The increased price of N for modified urea, expressed as a percentage increase over the price of conventional urea‐N, must be <20% when N saving = 17% of applied N, <40% when N saving = 29% of applied N, and <80% when N saving = 44% of applied N to obtain a positive increment in profit. The results suggest that modified urea would be most economical in environments with high response of the crop to urea‐N, high price of conventional urea, and high losses of urea‐N that can be prevented by the urea modification.
Monte Carlo Distributions of Parameters Relating to a Superiority Measure for Cultivar Assessment
Authors: Binns M. R. , Lin C. S.
Published: July 2010

A cultivar × location trial is the standard method for providing data by which new cultivars are assessed. To measure a test cultivar's general adaptability in such a trial, a superiority measure (designated as its Pi value) has been defined as the distance mean square between the test cultivar and the maximum yield at that particular location. A cultivar is considered to be better adapted if its Pi value is small. However, the distribution of differences from the maximum yield at each location in the context of cultivar × location data is unknown. This creates difficulties in measuring the difference between the cultivar mean and the mean of the maximum, and testing the pairwise interaction sum of squares between the maximum and the test cultivar. A computer program for Monte Carlo simulation can obtain approximations to the distribution of differences between the maximum location mean and a cultivar mean. This is then used to obtain probability intervals for comparing cultivar means with the location maximum. Approximate distributions are obtained for the Pi value and the pairwise genotype × environment interaction between the cultivar and the location maxima.
Effect of Nitrogen and Harvest Grain Moisture on Head Rice Yield
Authors: Jongkaewwattana Sakda , Geng Shu , Brandon Marlin D. , Hill James E.
Published: July 2010

In rice (Oryza sativa L.) production, both grain yield and milling quality play an important role in determining the grower's income. Nitrogen input is essential in maintaining a desirable yield, but its effect on rice milling quality is less clear. This study examined optimal N input for rice milling quality and the combined effect of N and grain moisture at harvest on both grain yield and head rice yield. Experiments were conducted in California at the Rice Experiment Station, Butte County, on three cultivars (S201, M201, and L202) during the 1987 and 1988 growing seasons to determine the effects and optimum levels of N and grain moisture at harvest on milling quality. Results showed that the optimal harvest grain moisture to produce the maximum head rice yield depended on the levels of N applied and ranged between 220 and 270 g kg−1 for S201, 210 to 270 g kg−1 for M201, and 200 to 250 g kg−1 for L202. The optimal N level for maximum head rice yield was 125 kg ha−1 for S201, 112 kg ha−1 for M201, and 130 kg ha−1 for L202. These optimum N rates fell within the lower half region of the required N for 0.95 confidence of producing the maximum grain yield. Thus, optimum N inputs for head rice yields are also likely to produce maximum grain yields for the cultivars studied. These findings will greatly simplify the management requirement on N application for California rice farming.
Photoperiod‐Induced Dormancy in Cicer Milkvetch
Authors: Townsend C. E.
Published: July 2010

Cicer milkvetch (Astragalus cicer L.) does not produce as much forage as alfalfa (Medicago sativa L.) under field conditions during the third growth period, which ranges from about 1 August to 15 September in Colorado. This study examined the effect of decreasing photoperiod on the herbage growth of cicer milkvetch. Spaced plants of the component polycross progenies of the cultivar Monarch were grown in the field under irrigation on a Nunn clay loam soil (fine, montmorillonitic, mesic Aridic Argiustoll). These progenies were subjected to one of four clipping treatments, removing the top growth on 18 July, 25 July, 1 August, or 8 August. Substantial variability was detected among plants within each clipping treatment date for extended height, which suggests that photoperiod was the primary factor controlling plant growth. Therefore, growth chamber studies were designed that exposed polycross progenies of selected germ plasm and Monarch to a constant 15‐h photoperiod and a gradually decreasing photoperiod equivalent to the natural daylength at Fort Collins, CO, from 1 August through 15 September. Plants under the decreasing photoperiod treatment were 23% shorter and produced 25% less shoot dry matter than those under the constant photoperiod. Under the decreasing photoperiod there were also fewer flowering plants and fewer racemes per plant than under the 15‐h photoperiod. Considerable variability for extended height and shoot dry weight was detected among plants under both photoperiods. These studies demonstrated the presence of a photoperiod‐induced dormancy trait in cicer milkvetch.
Modeling Tall Fescue Cultivar Response to Applied Nitrogen
Authors: Overman Allen R. , Wilkinson Stanley R.
Published: July 2010

Models can be used to estimate yields and nutrient utilization by forage grasses. The objective of this study was to model response of three cultivars of tall fescue (Festuca arundinacea Schreb.) to applied N over a 3‐yr period at Watkinsville, GA. The procedure uses analysis of variance to evaluate linear parameter A and the exponential parameters b and c for the logistic equation. It was shown that yields could be averaged across years and that all differences among cultivars could be assigned to the b (intercept) parameter. ‘All‐Triumph’ proved to be more efficient at converting soil N to dry matter without applied N than either ‘Johnstone’ or ‘Kentucky 31’ cultivars. Endophyte (Acremonium coenophialum Morgan‐Jones & Gams) infection did not affect dry matter response relationships of Kentucky 31. Maximum incremental conversion of applied N to dry matter occurred at N = 125 kg ha−1, where plant N utilization was ≈80%. The logistic model provides a very useful tool for evaluating response of tall fescue cultivars to applied N.
Boll Weight and Within‐Plant Yield Distribution in Field‐Grown Cotton Given Different Levels of Nitrogen
Authors: Boquet Donald J. , Moser Edgar Barry , Breitenbeck Gary A.
Published: July 2010

Increased understanding of N effects on fruiting and yield of cotton (Gossypium hirsutum L.) could lead to more efficient use of N fertilizer and increased yields. We determined the influence of N rate on boll size and yield distribution of cotton plants by measuring individual boll weights (IBW) and average seedcotton yield at each potential fruiting site (FS). Field experiments were conducted from 1987 through 1990 on Commerce silt loam (fine‐silty, mixed, nonacid, thermic Aeric Fluvaquent) to assess the response of cotton to preplant N rates of 0, 28, 56, 84, 112, 140, and 168 kg ha−1 and to a split application of 56 + 56 kg N ha−1. Increasing N rate from 0 to 84 kg ha−1 increased average whole‐plant IBW by 0.16 g and average yield per fruiting site by 0.29 g. Response of IBW and FS yield to N rate was dependent on the location of FS on the plant. Individual boll weight was maximized in Horizon 1 (mainstem nodes 5 through 10) with 28 kg N h−1, in Horizon 2 (mainstem nodes 11 through 16) with 56 kg N h−1, and in Horizon 3 (mainstem nodes 17 through 24) with 140 kg N h−1. Yield at fruiting site 1 (FS1) in Horizon 1 decreased from 2.3 to 1.7 g as N rate increased from 0 to 168 kg ha−1. Nitrogen fertilization of 84 kg ha−1 increased FS1 yield in Horizon 2 from 2.3 to 3.1 g, and increased FS1 yield in Horizon 3 from 0.27 to 1.1 g. Increasing N rate redistributed plant yield by decreasing the yield contribution of Horizon 1 from 43 to 28%, increasing the yield contribution of Horizon 2 from 44 to 48% and increasing the yield contribution of Horizon 3 from 7 to 22% of the total plant yield. The contribution of monopodial branches was <6% of total yield for all treatments and was decreased by application of >56 kg N ha−1. The application of optimal N rates benefited cotton yield by producing larger bolls at a greater number of fruiting sites. Increase in yield by increase in IBW and FS weight was limited, because gains in Horizon 3 were offset by negative responses in Horizon 1 when the N rate exceeded 84 kg ha−1