bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment Designs to Estimate Optimum Plant Density for Maximum Corn Grain Yield1
Authors: Carmer S. G.
Published: July 2010

Use of an exponential regression model relating corn (Zea mays L.) grain yield to plant density allows estimation of the optimum density for producing maximum yield. The experimenter's choice of treatment design (i.e. the particular plant densities included in an experiment) has an important influence on the precision of the estimated optimum density. The best treatment designs provide the greatest precision with a given number of replications, or, alternatively, provide a given level of precision with the smallest number of replications.

Expression of yield as a proportion of maximum yield and plant densities as proportions of the optimum density greatly simplifies the evaluation of treatment designs with respect to their ability to provide precise estimates of the optimum density. A total of 375 three, four, and five density treatment designs were evaluated on the dimensionless proportional scale in order to determine those which provide the greatest precision. Maximum allowable relative errors for the best three, four, and five density treatment designs are reported for each of 15 combinations of minimum and maximum densities expressed on a proportional scale. The best treatment designs contain unequally incremented densities and provide considerably more precise estimates of the optimum density than do designs with equally incremented densities.
Simulating Accumulation and Distribution of Dry Matter in Grain Sorghum1
Authors: Vanderlip R. L. , Arkin G. F.
Published: July 2010

Plant growth simulation models bring together what is known about various aspects of plant growth and dry matter accumulation. They are valuable in simulating the effects of management, environmental, or genetic factors on plant growth and in determining what areas of knowledge about plant growth are most lacking. However, most growth models deal only with total dry matter production. Reported here are submodels for calculating stage of development and partitioning dry matter production into plant parts based on these stages of development for grain sorghum (Sorghum bicolor L.).

Testing of the submodels using 25 data sets (from six locations in the sorghum growing area of the United States) including a number of hybrids, several years, and both irrigated and dryland production showed that the submodels provided unbiased estimates of: date of growing point differentiation; date of half‐bloom; physiological maturity; grain yield; and harvest index. Precision of modeling stages of development was acceptable for most uses (S.E. of 4.1 to 5.0 days). Standard errors for grain yield and harvest index were 18.4 g/plant (C.V. = 29.0%) and 0.06 (C.V. = 13.2%), respectively.
Analysis of a 12‐Year Corn‐Small Grain Rotation Experiment at Four Fertility Levels1
Authors: Harner E. James , Pohlman G. G. , Sperow C. B.
Published: July 2010

Seven 2‐year rotations were laid out in 1953 in order to determine the long term effects of fertilizer rate on the yields of corn‐small grain cropping systems on Wheeling fine sandy loam soil (ultic hapludalf). It was also desired to examine the effects of rotation and fertilizer rate on total digestible nutrient (TDN) production and soil nutrient content. Previously, little information of this nature was available. The rotations were corn (Zea mays L.), wheat (Triticum aestivum L.), corn‐winter barley (Hordeum vulgare L.), corn‐winter oats (Avena sativa L.), corn‐rye (Secale cereale L.), corn‐spring oats, corn silage‐winter barley, and corn silage‐winter oats. Fertilizer applications of 336 kg/ha, 672 kg/ha, 1,008 kg/ha, and 1,344 kg/ha of 5‐10‐10 fertilizer were applied annually.

The randomization and placement of crops and fertilizer was basically a split block with repeated measurements over time. Orthogonal contrasts were examined for the fertilizer, cycle, and rotation terms. The analysis was done in three parts: 1) for yields of each crop in each rotation; 2) for total digestible nutrients; and 3) for soil nutrients.

The conclusions of the statistical analysis are: 1) corn silage and most of the small grains had significant linear increases in yields with increasing levels of fertilization; 2) corn silage and some of the small grain crops had a significant linear fertilizer by cycle interaction; 3) TDN production, the gain of available soil P and K, and the loss of soil N were linearly related to fertilizer rates; and 4) TDN production was lowest for the corn grain‐oats rotations and highest for the corn silage rotations.
Chemical Growth Regulation of ‘Baron’ Kentucky Bluegrass1
Authors: Schmidt R. E. , Bingham S. W.
Published: July 2010

Effective chemical growth regulation is desirable in reducing mowing frequency of certain turf areas. The objectives of this field research were to study the influence of some promising growth regulators with and without repeated treatments during the 2nd year on ‘Baron’ Kentucky (Ky) bluegrass (Poa pratensis L.) and to determine the long term effects caused by persistent regulators. Mefluidide, diethanolamine salt of N‐[2.4 — dimethyl‐5‐[[(trifluoromehtyl) sulfonyl] amino]phenyl]acetamide; fluridamid, a diethanolamine salt of N‐[4‐methyl‐3[[(1, 1, 1,‐trifluoro‐methyl) sulfonyl]amino]phenyl]; metolachlot, [2.chloro‐N‐(2‐ethyl‐6‐methylphenyl‐N‐ (2‐methoxy‐l‐methyl‐ethyl) acetamide]; chlorflurenol (methyl‐2‐chloro‐9‐hydroxyfluorene‐9‐ carboxylate, methyl‐9‐hydroxylfluonene‐9‐carboxylate, methyl‐2, 7 dichloro‐9‐ hydroxyfluorene‐9‐carboxylate); CGA 17020, chemistry not released; and RO7‐6145, (2, 3: 4, 6 Bis‐0 ((1‐methylethybidene)‐(xxylo‐2‐Hexulofuranosonic acid), were applied twice in 1974 and once in 1975 to lawn turf grown on a Typic Hapludult clayey, kaolinitic, mesic soil. Treatments were randomized in a complete block design, and replicated three times.

All regulators and formulations evaluated caused some phytotoxicity, especially at higher dosages. Granular mefluidide did not reduce turf quality until after the 1975 application. No phytotoxicity was apparent for several weeks following each treatment of all regulators.

All regulators caused yield depressions the 1st month after each 1974 application. None caused a significant reduction in clipping weights after 2 months. Mefluidide EC and RO7‐6145 caused the longest yield suppression.

Approximately 1 month after retreatment in the 2nd year, all regulators reduced clipping yields. There was no apparent suppression after 2 months.

All regulators, except metolachlor, had less root growth than the control after a year following the 1974 application. Fluridamid and mefluidide suppressed rooting the most. Roots were suppressed by all regulators applied the 2nd year.

Regulators applied in 1974 stimulated seedhead production in 1975. Reapplication of treatments in 1975 suppressed inflorescence except treatments with RO7‐6145.

Mefluidide and fluridamid showed a reoccurance of phytotoxicity, and all regulators showed some yield suppression in 1976.

Regulators affected root growth for a longer period of time than they did foliage. Reapplication of regulators was required to continue suppression of shoot and inflorescence growth. Possibly, lower dosages should be used with subsequent treatments since regulator influence appears to persist for several years. Application of some regulators in late summer may enhance seed production by Ky bluegrass.
Sequential Herbicide Treatments for Large Crabgrass and Goosegrass Control in Bermudagrass1
Authors: Johnson B. J.
Published: July 2010

Large crabgrass [Digitaria sanguinalis (L.)] and goosegrass [Eleusine indica (L.) Gaertn.] are predominant summer weeds in most turfgrasses. A system for chemically controlling these weeds in late spring and early summer with the least amount of herbicide and labor is needed. Experiments were conducted to determine whether sequential herbicide treatments could be applied in June for control of emerged weeds present in bermudagrass [Cynodon dactylon (L.) Pers.] and prevent further germination of weed seeds during the remainder of the season. Combinations of preemergence and postemergence herbicides were applied in each of 2 years at Gritfin or control of large crabgrass and at Atlanta, Georgia for control of goosegrass. Sequential treatments of metribuzin [4‐amino‐6‐tert‐butyl.3‐(methylthio)‐as‐triazin‐b(4H)‐one] at 1.1 kg/ha with either bensulide [0,0‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl) benzenesulfonamide], oxadiazon [2‐tert‐butyl‐4‐(2,4. dichloro‐ 5‐isopropoxyphenyl) ‐ Δ2‐ 1,3,4‐oxadiazolin‐5‐one], butralin [4‐(1,1‐dimethylethyl)‐N‐(1‐methylpropyl)‐2,6‐dinitrobenzenamine], or napropamide [2‐(α‐naphthoxy)‐N,N‐diethylpropionamide] controlled a higher percentage of large crabgrass than when either chemical was applied alone. Single treatments of MSMA (monosodium methanearsonate) or methazole [2‐(3,4‐dichlorophenyl)‐4‐methyl‐1,2,4‐oxadiazolidine‐3,5‐dione] provide excellent control of large crabgrass. Goosegrass control was greater from sequential treatments of MSMA with oxadiazon, napropamide, or profluralin [N‐(cyclopropylmethyl)‐α,α, α‐trifluoro‐2,6‐dinit ro‐N‐propyl‐p‐toluidine ] than with MSMA alone. Methazole and metribuzin each controlled goosegrass almost completely.
Identification of Bark in Raw Cottons1
Authors: Morey P. R. , Wanjura D. F. , Baker R. V.
Published: July 2010

The presence of the trash component ‘bark’ reduces lint quality, but the constituents that make up the bark fraction have not been clearly identified. Botanical identification of bark constituents might lead to practices that reduce the presence of this trash material in lint. The objective of this study was to determine the botanical nature and the origin of the trash material that a Cotton Classer identified as bark in field‐grown Upland Cotton (Gossypium hirsutum L.) lint. Most barklike strands removed from lint at the wagon and at the feeder apron were identified in transverse sections as phloem fiber groups. A few barklike strands from the same samples were found to be wood fragments. The Shirley Analyzer was used to estimate the nonlint content of raw cotton. Ninety % of the barklike strands removed from visible Shirley Analyzer wastes of raw cotton consisted of phloem fiber groups. Anatomical study of transverse sections taken from the pedicel, fruiting branch, and main stem of three lots of cotton plants field grown on Amarillo loam (Aridic Paleustalfs) collected just prior to machine harvest showed that visual rating of barkiness in lint could not be associated with an excessive amount of phloem fibers in any one of these plant parts. The bark content in visible Shirley Analyzer wastes was determined by removing and weighing all barklike strands with a width greater than 25 µm and a length greater than 500 µm. Visual rating of degree of barkiness (DB) of lint at various stages of gin processing and total weight of visible Shirley Analyzer wastes did not accurately predict the content of barklike strands in visible Shirley Analyzer wastes. Stick content at the wagon and at the feeder apron was found to be the most accurate parameter for estimating bark content in visible Shirley Analyzer wastes of raw cottons.
Effects of a Commercial Nutrient and Evaluation of a Seedling Growth Technique1
Authors: Murphy C. F. , Burns J. C. , Nelson L. A.
Published: July 2010

The purpose of this study was to evaluate Seaquist®,3 a commercial nutrient solution advertised to increase grain and dry matter production and seedling responses of small grains when it is applied either as a foliar spray or as a seed treatment. Grain yield and seedling tests were conducted with ‘Blueboy II’ wheat (Triticum aestivum L.), ‘Yancey’ oats (Avena sativa L.), and ‘Clayton’ barley (Hordeum vulgare L.). A dry matter production test was conducted with Blueboy II wheat and ‘Keowee’ ley. Forage was harvested to simulate grazing and cutting silage. Seaquist treatments for the grain‐yield tests were: 1) seed treatment, 2) foliar application, 3) seed treatment + foliar application, and 4) check. Seaquist treatments for the dry‐matter production test were: 1) seed treatment, 2) seed treatment + three (grazing) or one (silage) foliar spray, 3) one foliar spray, 4) three (grazing) or two (silage) foliar sprays, and 5) check. In four seedling experiments the variables tested included treating seed with Seaquist at the recommended rate (R) and 0, ½R, 2R, 4R, 8R, and 16R; treating seed with Seaquist and a similar compound, Fortified Seaquist; use of the three small grain species; and use of distilled water and modified half‐strength Hoagland's solution as growth media.

Except for greater root growth after Seaquist treatment (compared to the check) in one of the four seedling tests, no significant differences attributable to Seaquist were found. However, when distilled water was compared with Hoagland's solution as the growth medium for seedlings, the nutrient solution caused a marked increase (2.13 cm) in top growth and a sizeable decrease (4.68 cm) in root growth.

A technique was developed for growing large numbers of seedlings in a relatively small space and measuring root and top growth after 10 days. The precision of this technique was evaluated. Increasing the number of replicates from two to four and increasing the number of seedlings/plot from four to 10 provided the greatest reduction in the size of the least significant difference. The number of replicates had a greater impact upon precision than did the number of seedlings.
Effects of Planting Date on Seed, Oil, and Forage Yields of Irrigated Sunflowers1
Authors: Murphy W. M.
Published: July 2010

Cool climates with short growing seasons of high intermountain areas, such as Central Oregon, limit the kinds of crops that can be grown. A wider choice of crops is needed for crop rotations and production changes. A substitute for corn (Zea mays L.) silage to supplement livestock energy requirements is also needed. Sunflower (Helianthus annuus L.) is a short season plant potentially useful for seed, oil, and forage crops. Sunflower forage has substituted for corn in silage in other areas. This study evaluated sunflowers for use as a new crop in Central Oregon. Eleven sunflower cultivars were planted in the field on 11‐14 April, 28‐29 April, 12 May, and 26‐28 May in 1975 and 1976. The effects of planting date on seed, oil, and forage yields were determined. Seed yields ranged from 1,694 to 2,082 kg/ha for the 1975 planting dates. The 28 April and 12 May planting dates resulted in highest yields. Seed yields among cultivars ranged from 1,560 to 2,183 kg/ha. In 1976, a late frost in June killed all cultivars planted on all dates except 12 May and reduced average seed yields to 412 kg/ha for the 12 May planting. Oil contents ranged from 38.5 to 41.8% for the 1975 planting dates. The three earliest dates recruited in highest oil contents. Oil contents were not determined in 1976 because of frost damage. Oil yields ranged from 707 to 873 kg/ha for the 1975 planting dates. Highest yields were from 28 April and 12 May planting dates. Oil yields among cultivars ranged from 700 to 900 kg/ha. Forage yields were determined only for the 12 and 26 May 1975 and 12 May 1976 planting dates. Dry for age yields averaged 9.9 metric tons/ha. This study showed that sunflowers are adapted to high intermountain conditions and that seed, oil, and forage yields would be sufficient to warrant their use. Mid‐May would be the optimum planting time for highest yields and least risk of frost damage.
Ethylene Regulation of Tobacco Seedling Size, Floral Induction, and Subsequent Growth and Development1
Authors: Kasperbauer M. J. , Hamilton J. L.
Published: July 2010

Tobacco (Nicotiana tabacum L.) seedlings in the starting bed may become too large for mechanical transplanting, especially during periods of rainy weather. Our objective was to hold the seedlings at a suitable size for transplanting without causing undesirable side effects. Ethephon (2‐chloroethylphosphonic acid) was used temporarily stop growth of seedlings in conventional starting beds and in various controlled environments. Resumption of growth was dependent on dosage of the chemical. Growth was suppressed for about 10 days in seedlings that were sprayed, until wet, with 1,000 mg ethephon per liter of solution. Seedlings treated at that level resumed normal growth and development after transplanting to the field. Ethephon treatments during the pretransplant period did not affect yield of cured leaf except when the plants were exposed to a florally inductive environment immediately after the treatment. In that case, ethephon‐treated plants flowered later and produced more leaves and higher yields than did nontreated plants. The seedlings were not responsive to a florally‐lnductive environment during the period of growth suppression. Growth was temporarily suppressed in plants treated in the noninductive environments, but growth later resumed and yield and alkaloid content of those plants were comparable to nontreated plants transplanted at the optimal size. Use of the ethylene‐releasing agent on rapidly growing tobacco seedlings in the starting bed offers the possibility of temporarily holding them at an optimal size without causing undesirable side‐effects.
Accumulation Sites of A1 in Snapbean and Cotton Roots1
Authors: Naidoo G. , McD. Stewart J. , Lewis R. J.
Published: July 2010

Aluminum toxicity is an important growth‐limiting factor in many acid soils. The exact site of A1 injury within roots is unknown. The objective of this study was to determine the site of A1 injury within roots of snapbeans (Phaseolus vulgaris L., ‘Dade’ and ‘Romano’) and cotton (Gossypium hirsutum L., ‘Hancock’) treated for 12 days with 20 mg/liter A1 in nutrient solution at pH 4.6. Location of A1 and other elements in roots was determined by X‐ray microanalysis on a scanning electron microscope. Linear scans across root sections revealed that A1 and P coprecipitate on or in the outer cells of the root cap. The major elements detected in spot analysis of nuclei, cytoplasm, and cell walls were A1, P, S, and Ca. Comparison of analyses on the three main cell structures revealed that the greatest concentration of A1 was in the nucleus. Within the cells, A1 probably accumulates by ionic exchange onto esteric P in the nucleic acids and membrane lipids. In the nuclei, A1 probabily reduces or inhibits cell division by interference with nucleic acid replication.
A Technique for Evaluating Nodulation Response of Soybean Genotypes1
Authors: Devine T. E. , Reisinger W. W.
Published: July 2010

The traditional Leonard Jar assembly technique for evaluating nodulation response has proved inadequate to accommodate the number of soybean (Glycine max (L.) Merr.) genotypes required in our breeding and genetic studies. A plexiglass apparatus consisting of plant growth trays suspended above a large nutrient reservoir was designed and tested as an alternative. The plant growth trays, 58 cm wide, 63 cm long, and 15 cm deep are filled to a 14‐cm depth with a light weight growing media, vermiculite or perlite. Portal tubes of plexiglass, 4.4 cm in diameter, connect the base of the growth trays to the nutrient solution in the reservoir. Two adjacent growth trays are fitted into a reservoir constructed of black plexiglass 61 cm wide, 130 cm long, and 11.4 cm deep. The reservoir holds 80 liters of solution, enough to supply the plants for at least 2 weeks without replenishment. Each apparatus accommodates 72 plants for an 8‐week growth period. The apparatus has proved efficient for the evaluation of large numbers of plants, with less maintenance than the traditional system.
Effect of P Placement on Yield of Tomatoes in Southwestern Nigeria1
Authors: Sobulo R. A. , Agboola A. A. , Fayemi A. A.
Published: July 2010

Research information developed under a temperate climate indicates that soil type, soil temperature, and soil moisture influence the response of arable crops to P placement methods. At a temperature of 10 C, banding was superior to broadcast while at 27 C (warm temperature) there was no difference between the two methods. Banding of P as opposed to broadcast was also suggested on tropical soils which have high phosphate‐fixing capacity to reduce P fixation. There is no research information in Nigeria on the best P placement method on tomatoes (Lycopersicon esculentum), which require a high rate of P for maximum fruit yield. Five common methods of fertilizer placement techniques in Nigeria were therefore evaluated on fruit yield response to P by this crop in a field experiment on two soil types varying widely in their P sorption capacity (PSC). The two soils were lju, a gleyic luvisol (FAO classification), and Alagba, a eutric nitosol, both derived from sedimentary materials in the rain forest zone of Nigeria. The methods were ring, band, broadcast, hole, and hill. The results of the study for five seasons mostly on rainfed tomatoes show that on a soil with a relatively high PSC, P banded was superior to broadcast in fruit yield production of tomatoes in a wet year though banding was not significantly better than ring and hill placement which are more laborious than the band method. In a dry year however, the broadcast method was sometimes better than the band method. Phosphorus placed 15 cm deep and 7.5 cm in a planting hole below the seedling was inferior to all the other methods under various soil water regimes. On a soil with a low P sorption capacity, the differences among the methods were not significant except hole placement which gave the lowest phosphate response. A combination of band and broadcast placement of P is therefore recommended in P fertilization of tomatoes in Nigeria.
Response of Corn to Low‐Rate Foliar Sprays of Dinoseb1
Authors: Johnson R. R. , McKibben G. E. , Jeppson R. G. , Jurgens S. K.
Published: July 2010

Corn (Zea mays L.) producers have expressed widespread interest in using low rate foliar sprays of 2‐sec‐butyl‐4,6‐dinitrophenol (dinoseb) as a growth regulator to enhance grain yield. In four experiments conducted at two locations during a 2‐year period, dinoseb was applied as nearly as possible to 3 weeks before tassel emergence to evaluate its effect on yield. Rates of 0, 7.4, 12.4, and 24.7 g dinoseb/ha were used in all experiments, and five adapted commercial hybrids and one two‐ear synthetic were used in the different experiments. Dinoseb applied to four hybrids at one location in 1975 caused a 6 to 8% yield decrease and a 1 to 2% increase in barrenness. An increase in nubbin ears (less than 40 kernels per ear) was also associated with the yield loss. During 1976, yield of the synthetic increased 4% at the 12.4 and 24.7 g/ha dinoseb rates, but a commercial hybrid in the same trials was not affected by treatment. Dinoseb affected the formation of second ears with both increases and decreases in this trait being observed at similar chemical rates. It is concluded that in these experiments corn responded in an unpredictable manner with dinoseb applications to different genotypes in different environments.
Yield and Elemental Composition of Flax as Affected by P and Micronutrients1
Authors: Spratt E. D. , Smid A. E.
Published: July 2010

Studies were conducted to ascertain how flax (Linum usitatissimum) would be affected by large amounts of P applied initially for wheat (Triticum aestivum L.). A Zn ✕ P interaction was suspected.

The residual P from 100, 200, and 400 kg P/ha applied in 1965 to two Manitoba soils (orthic haplustolls) affected the yields of flax in 1971 and 1972. In 1972 the levels of NaHCO3 extractable P in the surface soil ranged from 1.5 ppm where no fertilizer P was added to 46.5 ppm in the surface soil where 400 kg/ha of P was applied in 1965. The higher levels of P in the soil increased the P concentration in the plants, but the Zn and Cu concentrations were depressed to near critical levels in some cases. Field applications of Zn and Cu fertilizer did not increase flax seed yields.

In the growth chamber, increases in the levels of NaHCO3 extractable P in the soil increased the shoot and root yields, decreased fertilizer P uptake, and decreased Zn and Cu concentrations. Applications of fresh fertilizer P increased yields and further increases were obtained with P‐Zn‐Cu combinations. Concentrations of N, P, and K were similar in both the roots and shoots, but concentrations of Fe, Zn, and Cu were 25, 2, and 2 times greater, respectively, in the roots than in the shoots. Conversely, Mn concentrations were twice as great in the shoots as in the roots.

Flax crops grown on calcareous soils in Manitoba should be monitored for Zn deficiencies when NaHCO3 extractable P in the surface soil exceeds 20 ppm.
Effects of N Fertilization and Population Rate‐Spacing on Safflower Yield and other Characteristics1
Authors: Nasr H. G. , Katkhuda N. , Tannir L.
Published: July 2010

Since information on the culture of safflower in Lebanon is not yet available, field trials were conducted in 1973 and 1974 to: (a) determine the effects of N fertilization and (b) plant population spacing on safflower (Carthamus tinctorius) yields and other characteristics.

Nitrogen application at the rate of 75 kg N/ha was necessary for higher seed, oil, and protein yield when compared to the zero N. Rates of 150 kg N/ha or higher gave no additional yield increases, but significantly increased plant height and number of heads/plant. Seed weight and number of seeds/head were not affected. In 1973, when zero N was not included, differences in seed yield were not significant except for protein yield which increased with higher N rates. This was due to the significant increases in percent protein.

Increasing population rates from 133,333 to 266,667 and even to 533,333 plants/ha increased seed, oil, and protein yield and plant height. However, the number of heads/plant and number of seeds/head were reduced and seed weight, percent oil and percent protein were not affected. The 37.5 cm row spacing gave better yields than the 75 cm. Response to the 5 cm within row spacing as compared to the 10 cm was generally absent.

The interaction N by population rate‐spacing was not significant. However, the combination of 75 kg N/ha and the 10 cm × 37.5 cm spacing (266,667 plants/ha) appeared to have produced the most profitable seed yield (3,410 kg/ha).
Plant Maturity and Cutting Frequency Effect on Total Nonstructural Carbohydrate Percentages in the Stubble and Crown of Timothy and Orchardgrass1
Authors: Mislevy P. , Washko J. B. , Harrington J. D.
Published: July 2010

Concentration of total nonstructural carbohydrates (TNC) in perennial bunch‐grass stubble is an indicator of its physiological condition. However, there is little information connecting management systems with stubble carbohydrate reserves. The object of this study was to evaluate the influence of initial harvest and subsequent height of regrowth at cutting on TNC levels in the stubble and crown of ‘Climax’ timothy (Phleum pratense L.) and ‘Pennlate’ orchardgrass (Dactylis glomerata L.). Firstgrowth was harvested at: transition (changing of apical meristem from vegetative to reproductive growth), boot (flower head emergence), or anthesis stage. After initial harvest, regrowth was harvested at 10. to 15‐, 20‐ to 25‐,30‐ to 36‐, 41‐ to 46‐, or 51‐ to 56‐cm plant heights.

Both grasses had low TNC percentages (4 to 5%) at their transition stage. Delaying initial harvest of timothy until boot or anthesis stage increased stubble and crown TNC percentages four to five times.

Delaying initial harvest of orchardgrass to boot stage had little effect on stubble and crown TNC percentages. However, stubble‐crown reserves increased 5 percentage points when initial harvest was delayed to anthesis. With frequent harvesting of both grasses, TNC percentages remained low, but the trends of TNC increased as the frequency of harvest decreased. By early November both species had a high stubble and crown TNC percent. age regardless of the regrowth harvest schedule. Stubble and crown TNC percentage was generally lower by the following spring for all treatments, with orchardgrass exhibiting the greatest decrease. These data indicate that the seasonal trend of stubble and crown TNC accumulated by each grass species reflects the harvest management system imposed during that growing season.
Alfalfa Winter Injury, Survival, and Vigor Determined from Aerial Photographs1
Authors: Wallen V. R. , Jackson H. R.
Published: July 2010

Some of the difficulties of assessing the physiological condition of an experimental plant population are the necessarily repetitive observations and the extensive time required to accomplish a thorough survey. Based on earlier work by the authors, a study was conducted to determine if aerial photographs of a plot of alfalfa (Medicago sativa L.) could provide information on plant survival and vigor, soil moisture, and the influence of soil drainage on winter injury beyond that obtainable solely from field observations. Aerial photographs were made over an alfalfa plot originally containing over 10,000 plants using black‐and‐white and color‐infrared film. The photos were taken at 105 m with a 70 mm camera mounted on a helicopter. Visual assessments from the photographs made in the spring and fall of 1974 and in the spring of 1975 showed that from more than 6,000 surviving plants in 1974 only slightly more than 4,800 existed in the fall of that year; in the following spring, almost 400 more plants had not survived and from the total original population, 1,600 were rated as weak. Photointerpretation allowed an evaluation of plant vigor and the effect of soil drainage and high moisture on winter injury and survival. The study demonstrated that the use of aerial photographs, in addition to providing a permanent record of field conditions at a time selected by the plant breeder or pathologist, permitted large areas to be recorded and, because of their permanancy, increased the capability of reassessment.
Lime and P Applications and Their Residual Effects on Corn Yields1
Authors: Lim K. L. , Shen T. C.
Published: July 2010

Lime need for corn (Zea mays L.) production has been widely recognized in Malaysian soils. Little work has been done, however, to study the chemical behaviour of these soils after applications of lime. This field study was conducted to monitor some of the chemical changes in a Serdang colluvium (Tropofluvent) soil when lime and phosphate fertilizer were applied to corn. The residual effects of these treatments on the nutrition and yield of corn were also studied. Six consecutive corn crops were grown over a 2‐year period. Ground limestone (CaCO3) at 0, 3,000, and 6,000 kg/ha and P (triple superphosphate) at 50, 100, and 150 kg/ha were applied. Ground limestone was applied for the first crop and half of the P levels were applied for the first crop while the other for the second crop. Their residual effects were observed for six crops. Results indicated that 3,000 kg/ ha of limestone was sufficient to maintain yields for the first three crops while 6,000 kg/ha provided sufficient lime for all six crops. Grain yield responded significantly to 100 kg/ha P and continued to provide enough P through the sixth crop. Liming increased soil pH from 4.3 to 5.5 and decreased exchangeable AI and % AI saturation from 1.9 to 0.3 meq and 67 to 7%, respectively. A strong negative relationship existed between grain yield and exchangeable AI which accounted for 74% of the yield variations. Leaf Mg concentration was also increased from 0.14% to 0.40% with lime application. Plant analysis showed that poor plant growth on unlimited plots was not due to poor P uptake. Grain yield, available P, and leaf P concentration relationships showed critical available P at 25 ppm and P concentration at 0.27%.
Volatilization of Microencapsulated and Conventionally Applied Chlorpropham in the Field1
Authors: Turner B. C. , Glotfelty D. E. , Taylor A. W. , Watson D. R.
Published: July 2010

The effectiveness of preemergence applications of herbicides to soil surfaces may be seriously reduced by losses due to volatilization to the air. Direct measurements of volatilization rates of two chlozopropham (isopropyl‐m‐chlorocarbanilate) formulations, a microencapsulated and a conventional emulsifiable concentrate, were made to establish the differences in volatilization rates in the field. During the first day after application to a bare silt loam soil, without cultivation, on 25 May, the volatilization from the encapsulated residues was about one.third that from the emulsified material. Volatilization decreased rapidly over the first 3 days, when 60% of the encapsulated and 30% of the emulsified chlorpropham remained in the target area. Volatilization was still measurable after 50 days, when 20% of the encapsulated and 2% of the emulsified remained. Over this whole period the emulsified residues volatilized about five times faster than the encapsulated. The results indicate the potential value of microencapsulaton techniques for controlling vapor losses and increasing the persistence of volatile herbicides in the field.
Spring Wheat Yield Model for Limited Moisture Conditions1
Authors: Rasmussen V. P. , Hanks R. J.
Published: July 2010

Models are useful to predict the effect of one or more of the complex climatic soil, water, or crop variables on yield. Such predictions can be used to make economic evaluation of, for example, the cost and benefit of irrigation or date of planting on yield. The objective of this study was to develop a model for spring wheat (Triticum aestivum L.) which could be used for such purposes and which required only readily available data. The model, a modified form of that developed by Hanks (1974) for corn (Zea mays L.), is based on a water balance of irrigation, precipitation, soil water, evapotranspiration, and drainage. Relative dry matter yield is assumed to be directly related to relative seasonal transpiration. Relative grain yield is assumed to be related to the multiple of relative transpiration for each of four growth stages raised to the 0.25 power.

The validity of the model was tested in 1975 using field experimental data collected especially for this purpose. Two soft white spring wheat and three hard red spring wheat cultivars were grown under several levels of irrigation. Predicted yields agreed closely with measured yields. An additional test of the validity of the model for other irrigated cultivar trials in 1975, 1974, 1973, and 1972 at the same location, and a dryland trial in 1975 at another location, was made. Good agreement with measured results was found for the 1973, 1974, and 1975 irrigated and the 1975 dryland trial. However, the predicted results for the 1972 irrigated trials were about 20% lower than the measured yields.
Nitrogen Fertilization of Irrigated Russian‐Thistle Forage. I. Yield and Water Use Efficiency1
Authors: Fowler J. L. , Hageman J. H.
Published: July 2010

Reports on yield, water use efficiency, and nutritive value of Russian‐thistle (Salsola spp.) have suggested its potential as a forage crop for areas with limited water resources. This study was initiated to determine the effect of N fertilization, irrigation management, time of first harvest, and cutting height on the yield and water use efficiency of Russian thistle. Russian‐thistle was grown in irrigated field plots in 1975 and 1976. The influence of N fertilization (0, 28, 56, 112, and 224 kg N/ha), stage of maturity at first harvest (prebloom and 3/4 bloom), and cutting height (7.5 and 15.0 cm) on dry matter yield and water use efficiency was evaluated in 1975. Yield and water use efficiency generally improved as N application rates increased. Thistle harvested at 3/4 bloom produced 3,600 kg/ha more dry matter and 27% more shoot dry weight/ha‐cm of water applied than thistle cut at prebloom. Cutting at 15 cm increased yield by 8 and 15% at prebloom and 3/4 bloom, respectively, over that at 7.5 cm. In 1976, application of N (0, 28, 56, and 112 kg N/ha) generally improved both yield and water use efficiency. Quantity of water applied (24, 35, 40, and 60 cm) did not significantly affect yield but the highest application reduced water use efficiency. No N fertilizer ✕ irrigation interactions occurred. Forage yields ranged from 6,090 to 11,009 kg/ha and water use efficiency from 102 to 414 kg shoot dry weight/ha‐cm of water applied.
Seasonal Patterns of Forage Quality of Weeping Lovegrass Cultivars1
Authors: Holt E. C. , Dalrymple R. L.
Published: July 2010

Weeping lovegrass (Eragrostis curvula (Schrad.) Nees) is used for grazing in both the growing season and the dormant season, yet little information is available on seasonal patterns of forage digestibility, particularly in the dormant season. A study was conducted to determine the influence of N on dry matter digestibility of forage in the growing season and stockpiled forage in the dormant season. Four cultivars with known differences in forage palatibility were fertilized at three N levels and harvested at intervals during the growing and dormant seasons. In vitro digestible dry matter (IVDDM) was determined during a 3‐year period. ‘Morpa’ and ‘Renner,’ both selected for palability, tended to be higher in IVDDM than ‘Ermelo’ and ‘Common’ weeping lovegrass. The initial spring growth ranged from 60 to 67% IVDDM. Digestibility declined 10 to 20 units from April to August or September, increased in August or September in some years, and then declined to lows of 28 to 48% in January and February. Renner and Morpa showed more August–September recovery in IVDDM than Ermelo and Common. Neither the amount nor time of N fertilization had any influence on forage digestibility. Seasonal differences in digestibility were greater than cultivar differences. Forage digestibility in both midsummer and midwinter may reach low enough levels to limit animal performance if not supplemented.
Molybdenum and Sulfur Interaction Effects on Growth, Yield, and Selected Chemical Constituents of Burley Tobacco1
Authors: Sims J. L. , Leggett J. E. , Pal U. R.
Published: July 2010

Molybdenum accumulation by plants is decreased by high levels of SO42‐ in the rooting media. This relationship is of interest since Mo is deficient in some soils, and certain fertilizers contain large amounts of SO42‐. The present study was conducted to determine the effect of MoO42‐and SO42‐ interaction on growth, yield, and selected chemical constituents of burley tobacco (Nicotiana tabacum L.), Tobacco (CV ‘Ky‐14’) was grown in a field experiment during 2 years. Treatments consisted of four rates of Na2Mo04 (0, 0.56, 1.12, and 2.24 kg/ha) applied annually in all combinations with four rates of SO42‐ (0, 112, 224, and 448 kg/ha) to Maury silt loam soil (Typic Paleudalfs). Plant samples were taken at varying dates during one growing season for chemical measurements while cured leaf yields were measured both years.

Adding Na2Mo04 increased average Mo concentration of leaves over the control (about threefold), nitrate reductase activity of leaves (35%), N content of the total plant (5 to 10%), and cured leaf yields (7%). Adding SO42‐ fertilizers decreased Mo concentration (33 to 55%, but increased total N content (5 to 10%) and cured leaf yields (7%). Sulfate had no effect on S concentration at any sampling date, but a trend existed for SO42‐ to lower nitrate reductase activity.

Significant Mo rate × SO42‐ rate interactions existed for Mo concentrations, total N content, and yields of cured leaf. These interactions suggest that adding SO42‐ fertilizer will have detrimental effects on plant growth, nitrate reduction, and leaf yields at low soil Mo levels but positive effects at high soil Mo levels.
Growth and Mineral Composition of Mungbean as Influenced by P and Fe Fertilization1
Authors: Bassiri A , Kashirad A , Kheradnam M
Published: July 2010

Phosphorus is among the principal nutrient elements needed for growth by many crops in arid and semi‐arid agricultural regions. The advantageous effects of P, especially for legumes, have been studied in detail. However, relatively large amounts of soil P interfere with the availability of Fe to plants. The effects of P and Fe on growth and mineral composition of mungbeans, Phaseolus aureus (Roxb.) Hepper, are reported herein. Mungbeans were grown for 8 weeks in a silty clay soil, classified as Xerollic Xerochrept, treated with levels of P (0,50,100, and 200 ppm) and Fe (0,5,10, and 20 ppm). Maximum top and root dry weight and plant height occurred with 50 ppm P. Iron treatments reduced top and root dry weight and plant height. It was concluded that mungbeans required 50 ppm P and no Fe for optimum growth in this soil under the conditions of this experiment. Increased levels of P in the soil caused significantly higher P uptake, greater P and N concentration, and lower Zn concentration in the tops. The concentration of Fe, N, K, and Ca in the tops was significantly increased, while the concentration of Mg and the uptake of P, N, K, Ca, Mg, and Zn decreased with increasing Fe levels in the soil.
Relationship of Week of Flowering and Parameters of Boll Yield in Cotton1
Authors: Turner J. H. , Worley S. , Ramey H. H. , Hoskinson P. E. , Stewart J. M.
Published: July 2010

Cotton (Gossypium hirsutum L.) experiments generally are reported in yield per unit area of land. This yield is a product of number of bolls per unit area and yield per boll. Estimates of yield per boll include an element of sampling. Our purpose was to relate week of flowering to the variability of boll yield components. Boll samples derived from 5 consecutive weeks (periods) of blooming in six diverse cotton cultivars in 1974 and 1975 were used to estimate the separate seed and fiber parameters that are components of boll yield. Seed yield per boll (SY/B) declined from the first through then fifth period of bloom, due to a significant loss in weight per seed ( g / S ) . Seed number (S/B) was lowest from first period fruit. Fiber yield per boll (FY/B) increased from the first to third period of bloom, but decreased sharply the last two periods. The weight per fiber (μg/f) was the main component to influence fiber yield adversely in late season bolls. The number of fibers per mm2 of seed surface showed a differential response for the two seasons over the bloom periods. Seed surface area (S.S.A./S) was influenced b bloom periods, cultivars and years. All components or FY/B gave significant year × period interactions. These data suggest that sampling should emphasize bolls derived from bolls set during the peak of flowering. Further implications of these results upon sampling technique in cotton research are discussed.
Influence of Different Levels of Irrigation and Nitrogen on Yield and Nutrient Uptake by Wheat1
Authors: Singh N. T. , Vig A. C. , Singh Rachhpal , Chaudhary M. R.
Published: July 2010

Irrigation and fertilizers are two vital but costly inputs in irrigated agriculture. Their economic use demands that maximum yield should be obtained per unit application of these inputs. A constraint on irrigation water supply must accompany a corresponding cut on fertilizer application and vice versa. A study was, therefore, conducted to find out the response of wheat (Triticum aestivum L.) to different levels of irrigation and N for 3 years in a deep sandy loam soil underlain by a clay loam, belonging to the family fine loamy, hyperthermic, mixed, calcareous, Typic Ustocherpt. The irrigation treatments were check, 1, 2, and 3 irrigations applied according to irrigation water applied per pan evaporation ratio of 0.90 and N levels were 60, 80, 100, and 120 kg N/ha. In the normal rainfall years of 1974–75 and 1976–77, wheat yield increased with number of irrigations. In the unusually wet year of 1975–76, however, response to irrigation was non‐significant. No response was observed beyond a N application of 80 kg/ha without irrigation, whereas, the response was linear up to 120 kg N/ha in the three irrigation treatment. The uptake of N was a linear relationship with crop yield. Apparent water use by the crop increased in the high rainfall year and with increasing number of irrigations.
Associations Among Seed Weight, Seedling Emergence, and Planting Depth in Cicer Milkvetch1
Authors: Townsend C. E.
Published: July 2010

There is a great need for forage legumes that can emerge from deep depths of planting in semiarid environments because deep depths provide a greater cushion against the fluctuating moisture conditions found near the soil surface. Therefore, the objectives of this study were to compare selected progenies of cicer milkvetch, Astragalus cicer L., with seed weights of 3.2, 3.6, 4.0, 4.4, 4.8, 5.2, and 5.6 g/1,000 seeds for seedling traits that might be related to emergence and for ability to emerge from 1.3, 2.5, and 3.8‐cm depths of planting in the field.

Seedlings from the seven seed classes differed significantly for hypocotyl diameter, hypocotyl length, radicle length, total length, and dry weight when grown in a dark germinator for 7 days at 25/15 C. In a greenhouse study the seed classes differed significantly for cotyledon dry weight, but not for cotyledon area, when sampled at the earlyprimary leaf stage. In both studies the values for the various characters generally were greater for the highseed‐weight classes than for the low.

Although there were large differences between dates of planting both within and between years for seedling emergence in the field, the trends were similar with the high‐seed‐weight classes giving the greatest average emergence. The greatest difference among seed classes occurred at the 3.8‐cm depth, where seedling emergence of the 5.6‐g class was about twice that of the 3.2‐g class. Seedling emergence was similar for the 1.3 and 2.5‐cm depths of planting and generally was much higher for these two depths than for the 3.8‐cm depth. Correlation coefficients between seed weight, the various seedling traits, and seedling emergence at the 3.8‐cm depth were generally significant except for those involving hypocotyl length.
Soybean Leaf N as Influenced by Seedbed Preparation Methods and Stages of Growth1
Authors: Young J. K. , Whisler F. D. , Hodges H. F.
Published: July 2010

Recent interest and studies on nitrogen relationships in soybeans [Glycine max (L.) Merrill] have led to a better understanding of the processes regarding N accumulation during vegetative growth and remobilization during seed development. Most of the research work was performed with different N fertilizer treatments and isolines of nodulating and nonnodulating soybeans. Differences in cultural practices which modify the root environment and differences in soybean cultivar have not received much attention in N accumulation and remobilization studies. The objectives of this work are 1) To determine the effect of tillage treatments and cultivar on leaf N levels and 2) to develop a regression equation relating several plant and cultural variables to leaf N levels.

‘Forrest’ and ‘Tracy’ cultivars of soybeans were planted on Houston silty clay (very fine montmorillonitic, thermic family of Typic chromuderts) with seven different seedbed preparation methods and assayed for leaf N using the Kjeldhal method. Leaf N concentrations of the two cultivars showed similar patterns of change over the sampling period at each of three positions (top, middle, bottom) on the plant. Tracy had higher leaf N concentrations (5.3 to 3.2%) than Forrest (5.0 to 2.9%) throughout the growing season. Topleaf N remained fairly constant until late R2 maturity stage, after which it decreased rapidly. Middle‐leaf N varied as a quadratic function of plant age. An inverse relationship between lower‐leaf N and plant age was observed. For different cultivars, tillage affected leaf N within each leaf position in the early growing season. A regression model having factors of plant age, cultivar, leaf position and interactions of these factors predicted leaf N with a standard error of estimate of 0.33% and a coefficient of variation (R2) of 0.85.