bluuebunny/crossref_metadata_2025 huggingface dataset:
Cotton Growth Response and B Distribution from Foliar Application of B
Authors: Anderson O. E. , Ohki Kenneth
Published: July 2010

Foliar application of B has been frequently used to ameliorate B deficiency in cotton (Gossypium hirsutum L.) in the field. This study was initiated to provide information on B distribution pattern and growth responses from foliar application under greenhouse conditions.

Boron was applied to cotton foliage in the greenhouse at three application dates by paint or spray application at the 5 to 7‐leaf, early square, and early boll stages. Plants were harvested between 6 and 72 days after application. Growth responses and B content of tissues were related to applied B.

Within application periods, foliar applied B had no effect on top growth, root development, reproductive tissue, plant height, and node number. Boron content of treated leaf blades, sampled at the first harvest after application, showed B levels greater than controls. As indicated by B analysis of petiole and young tips, no evidence of B retranslocation in the main stem tissues was apparent.
Yield of Flue‐Cured Tobacco and Levels of Soil Oxygen in Lysimeters with Different Water Table Depths1
Authors: Campbell R. B. , Seaborn G. T.
Published: July 2010

Flue‐cured tobacco (Nicotiana tabacum L.) was grown in lysimeters with static water. table levels at, 30, 45, 60, and 90 cm below the soil surface to more clearly define the level at which a favorable balance between soil aeration and water supply is attained. The oxygen and CO2 content of the soil air was determined periodically at various depths. Water‐table treatment effects were evaluated in terms of root and shoot growth, yield, and quality of tobacco.

Dry leaf yields for the 90‐, 60‐, and 45‐cm water‐table treatments were all significantly (P≥0.05) greater than that for the 30‐cm treatment. Yields for the 60‐ and 90‐ cm water‐table levels were larger, but not significantly (P≥0.05) larger than the 45‐cm treatment. The yield difference between the 60‐ and 90‐cm treatments was not significant (P≥0.05). Roots of tobacco recovered from soil above the 60‐ and 90‐cm water tables weighed only 10% more than roots recovered from soil above the 30‐ cm water table. Average CO2 and O2 gradients in the soil above the water table were nearly equal but of opposite sign. Soil environmental conditions imposed by the 60‐cm water‐table treatment of this study provided the most favorable balance between aeration and water supply for tobacco.
Effect of Fertilizer Nitrogen, Phosphorus, and Potassium on Yield and Nutrient Content of Lee Soybeans1
Authors: Bhangoo M. S. , Albritton D. J.
Published: July 2010

Further studies on mineral nutrition of soybeans [Glycine max (L.) Merrill] were needed for better understanding of the relationship between the nutrient contents of the grain and leaf tissue in relation to grain yield as influenced by N, P, and K fertilization.

Field experiments with ‘Lee’ soybeans were conducted over a 3‐year period on a Calloway silt loam in southeast Arkansas to obtain data on the effects of various rates and combinations of N, P, and K (112 kg N/ha, 40 kg P/ha, and 75 kg K/ha) fertilizers on grain yield and on the elemental content of leaf tissue and the grain.

Marked yield increases were obtained from N and K fertilizers and from various NPK combinations. Yield increases from N ranged from 10 to 15%, and from K, from 9 to 19%. Yield increases in 1967, 1968, and 1969 from NPK over the check were 32.8, 28.3, and 14.7%, respectively.

Fertilizer application increased the N and K content of both the leaves and grain and depressed their Ca and Mg content. Soybean yield showed a positive correlation with the N and K and negative correlation with the Ca and Mg content of grain and leaf tissue. Elemental content of the leaf tissue declined with plant age.
Nitrogen‐supplying Power of Some Tropical Soils of Puerto Rico and Methods for its Evaluation1
Authors: Lathwell D. J. , Dubey H. D. , Fox R. H.
Published: July 2010

An evaluation of the N‐supplying power of 10 representative Oxisols and Ultisols of Puerto Rico was made by continuous cropping in the greenhouse. Four chemical extraction methods as well as aerobic incubation procedures were used to obtain an index of N availability in these soils. Nitrogen produced during incubation was highly correlated with N released to the crops. Nitrogen extracted by all of the chemical methods used, especially total N extracted by 0.01 M CaCl2 solution and potassium sulfate, was highly correlated with N uptake by plants. These results showed that substantial quantities of N can be removed from these soils upon cropping. It was also shown that laboratory chemical methods as well as incubation procedures provide a reliable means for evaluating the N‐supplying power of these soils.
Temperature Requirements for Seed Germination of Several Forage Legumes1
Authors: Townsend C. E. , McGinnies W. J.
Published: July 2010

Species that germinate readily over a relatively wide range of temperatures should be easier to establish in the field than those with highly specific temperature requirements. This study compared the temperature requirements for seed germination of several native and introduced legume species with those of commonly used species.

Seed germination of 17 legumes species was studied under dark conditions at alternating temperatures of 5 C – 20 C, 15 – 25 C, 20 – 35 C, and constant 20 C. Duration of the alternating temperatures was 12 hr. Seedling counts were taken on the 7th, 14th, 21st, and 28th days of germination.

Species differed significantly in germination response to temperature. Medicago sativa L. var ‘Ladak 65,’ Onobrychis viciaefolia Scop. vat. ‘Eski,’ Oxytropis riparia Litv., an unidentified Astragalus sp., A. canadensis L., A. galegiformis L., and A. falcatus Lam. were considered to be temperature‐insensitive for total germination because there was very little difference in percentage germination within each of these species on the 28th day at the four temperature treatments. Half of these species, however, were at least moderately sensitive to temperature for rate of germination.

There was considerable interaction among some species and temperatures for both total germination and rate of germination. Astragalus glycyphyllos L., A. globiceps Bge., A. dahuricus (Pall.) DC., and A. chinensis L. required relatively high temperatures (15 – 25 C or 20 – 35 C) for good germination. These temperatures, however, markedly reduced germination of Desmanthus illinoensis (Michx.) MacMill. The 20 – 35 C treatment also seriously reduced germination of Coronilla varia L. var. ‘Chemung’ and slightly reduced germinatiou of Astragalus striatus Nutt., A. flexuosus (Dougl.) G. Don, and Vicia tenuifolia Roth. In comparison to other treatments, rate of germination at constant 20 C was especially high for V. tenuifolia, D. illinoensis, and C. varia. Germination response of Astragalus cicer L. differed from other species. Rate of germination and total germination increased with increase in temperature through 15 – 25 C. At 20 – 35 C, total germination dropped substantially, but rate of germination remained high.

Temperature requirements for seed germination of some species suggest why they are relatively easy or difficult to establish in the field. The species that germinated well at most temperatures but are difficult to establish are very small seeded.
Influence of Row Width and Population Density on Yield and Fiber Characteristics of Cotton1
Authors: Hawkins B. S. , Peacock H. A.
Published: July 2010

A critical need to evaluate methods to reduce production costs of Upland cotton (Gossypium hirsutum L.) to help maintain its. competitive market position, prompted experiments designed to evaluate the influence of row width and plant population on yield and fiber properties. Upland cotton was grown in 25.4‐, 50.8‐, 76.2‐, and 101.6‐cm‐spaced rows with population levels of 128,000 (low) and 256,000 (high) plants/ha at three locations in Georgia. Significant differences in yield due to test location and to row width were found, but differences in plant populations did not affect yield.

Seeding with a modified grain drill produced 88% of the plants desired at the low population level and 82% at the high population level, but left much to be desired in uniformity of seed distribution, placement, and coverage.

We found no difference in lint percentage and seed size except that due to location. Boll size was affected by plant population and location but not by row width. The only fiber characteristic affected by row width was fiber fineness. Earliness was influenced only by location. Significant interactions of row width × location were found for yield, number of plants, lint percentage, and fineness. The population × location interaction was significant for boll size and number of plants. The second order interaction of population × row width × location was significant for boll size. Results relative to yield were encouraging and indicated that the narrow‐row, high‐population system might provide partial solutions to some production problems.
Effect of Rates of Nitrogen on Yield, Nitrogen Use, and Winter Survival of Midland Bermudagrass [Cynodon dactylon (L.) Pers.] in Appalachia1
Authors: Mathias E. L. , Bennett O. L. , Lundberg P. E.
Published: July 2010

This study was conducted to determine if Midland bermudagrass [Cynodon dactylon (L.) Pers.] could be utilized in the region of Appalachia as a summer forage during the midsummer months when cool‐season grasses are relatively nonproductive. The effects of N rate on yield and longevity of Midland bermudagrass were studied for 3 years in northern West Virginia. Nitrogen at rates of 112, 224, 448, and 672 kg/ha/yr was split into three equal applications. Dry matter yields were increased with each increment of N during the 1st and the 2nd years and through the 448‐kg/ha rate in the 3rd year. Nitrogen content of the forage increased with increasing rates of N and was greater in the second harvest than in the first. Percent recovery of applied N was highest at the 224‐kg/ha rate in the 1st and the 2nd years and at the 448‐kg/ha rate in the 3rd year. Where adequate N was supplied, bermudagrass competed effectively with native grasses and thus survived three winters, even though the temperatures reached as low as −22 C. By the 3rd year annual yields were as high as 16,000 kg/ha.
Determination of Total Nitrogen in Plant Material1
Authors: Nelson D. W. , Sommers L. E.
Published: July 2010

A simple and precise procedure for estimating total N in plant tissue is described; a modification is also described for analysis of samples containing high nitrate concentrations. Plant tissue samples are placed in pyrex Folin‐Wu tubes and digested with a salt‐catalyst‐sulfuric acid mixture by heating the tubes in an aluminum block. Samples are digested at the boiling point of the mixture for 60 min after initial clearing of the digests. Analyses of diverse plant materials, containing from 0.006 to 0.3% NO3‐N3 indicated that the proposed and standard AOAC procedures yielded essentially the same total N values. The coefficient of variation for the proposed methods varied from 0.87 to 1.10%. The tube digestion procedures described allows digestion of 60 plant samples simultaneously and thus greatly improve the efficiency of total N determinations.
Visual Quantification of Wheat Development1
Authors: Haun J. R.
Published: July 2010

Changes in the morphology of winter and spring wheat (Triticum aestivum L. em. Thell.) were quantified in a manner to provide a continuous numerical expression of plant development during the formative growth period. The notation system makes use of the regular appearance of leaves at the growing point. Each new leaf represents a unit of development. After the flag leaf has emerged the remaining visible morphological development is divided into four additional units. The growth units are subdivided into decimal fractions beginning with the appearance of each leaf or subsequent unit and ending with the appearance of the next. The daily status or stage of plant development is designated as the total number of units plus the fractional portion of the next unit. The rate of development is determined by subtraction of the previous stage of development from the current stage. Statistical analyses were made to determine the validity of the system with respect to uniformity of designated development units. The system of observation provides a convenient and sensitive method for objectively documenting the status of development throughout the season, or for evaluating the growth response to various treatments or environmental conditions.
Reflectance Discrimination of Cotton and Corn at Four Growth Stages1
Authors: Gausman H. W. , Allen W. A. , Cardenas R. , Richardson A. J.
Published: July 2010

Increasing leaf age of corn within four growth stages had little effect on near‐infrared light (750‐ to 1350‐nm wavelength interval) reflectance, whereas mature leaves of cotton had higher near‐infrared light reflectance than young leaves.

Reflectance was linearly correlated with chlorophyll concentration for the four growth stages of corn (r −0.75**) at the 550‐nm wavelength; the linear correlation of reflectance with chlorophyll for the four growth stages of cotton was significant (r −0.71**) at the 650‐nm wavelength.

The largest differences among reflectances of corn leaves of different ages within growth stages occurred when tassels were appearing in the leaf whorls; this may be the best time to discriminate corn from other vegetation with remote sensors. Reflectance differences among cotton leaves within the four growth stages were similar. Spectral wavelength intervals centered around the 680‐, 850‐, 1,650‐, and 2,200‐nm wavelengths provide for the optimum discrimination of vegetation.
Diffuse Reflectance Hypothesis for the Pathway of Solar Radiation Through Leaves1
Authors: Sinclair T. R. , Schreiber M. M. , Hoffer R. M.
Published: July 2010

The Willstätter and Stoll theory explains leaf reflectance as critical or total reflection of light at cell wall‐air interfaces of spongy mesophyll tissue, and is based on observations of the spectral properties of leaves in the visible wavelengths. Our data, obtained in the 0.72 to 1.3 μm (reflective infrared) wavelengths, showed that unexpectedly high levels of reflectance occurred from palisade tissue and from dehydrated leaves that had collapsed internal structures.

A modification of the Willstätter‐Stoll theory, termed the diffuse reflectance hypothesis, allows a satisfactory explanation of the observed spectral properties of leaves in the reflective infrared, as well as the visible wavelengths.
Effect of Antitranspirants on Yield of Grain Sorghum Under Limited Irrigation1
Authors: Fuehring H. D.
Published: July 2010

Most crops of grain sorghum are grown under conditions of limited irrigation or rainfall. Reduction of the degree and length of periods of moisture stress through the use of antitranspirants to control stomatal opening may increase the amount of time when photosynthesis takes place thus increasing crop yield with the water available. The purpose of this study was to determine the proper material, method, and timing of application for field use. Under limited irrigation conditions in the field, grain sorghum (Sorghum bicolor (L.) Moench) was sprayed at various rates and times with phenylmercuric acetate (PMA), atrazine, and Folicote. Mean grain yield increases of 5 to 17% were obtained, indicating considerable economic possibility. Rates of application required were aproximately 60 g/ha for PMA, 130 g/ha for atrazine, and 2 liters/ha for Folicote. However, more work is needed on rates and volume of spray. Application just prior to the boot stage was more effective than a later application.
Seed Dormancy and Germination in Indiangrass as Affected by Light, Chilling, and Certain Chemical Treatments1
Authors: Emal James G. , Conard E. C.
Published: July 2010

The lack of published reports on the effects of chemicals and light on germination of dormant indiangrass (Sorghastrum nutans (L.) Nash) seed prompted this study. Cleaned hand‐harvested spikelets were planted between layers of germination toweling in covered plastic boxes, or on top of or between several layers of filter paper in plastic petri dishes. Each germination test consisted of 4 replicates of 100 spikelets, with or without moist prechilling at 4‐6 C for 2 or 4 weeks, held for 7 to 15 days at alternating temperatures of 18–22 C (night) and 25–28 C (day), with or without light. Some tests received red light. In other tests, various concentrations of gibberellic acid were used as the moistening agent; in others, seeds were presoaked in sodium hypochlorite or sulfuric acid.

Spikelets stored dry at room temperature (18–28 C) remained dormant for 7 months before dormancy began to decline. Pregermination moist chilling for 4 weeks usually resulted in near maximum germination. Light was required for maximum germination of seed chilled for 2 weeks. Red light was more effective than daylight when exposure time was 2 hours or less. Generally, spikelets failed to respond to light once they had failed to germinate in the dark. Soaking spikelets in sodium hypo‐chlorite solution increased germination only in the presence of light. Sulfuric acid and gibberelic acid treatments increased germination in the dark, but higher germinations were obtained in the presence of daylight.
Effect of Different Tillage Methods on Growth and Yield of Silage Corn1
Authors: Hakimi A. H. , Erami A. , Ghorashy S. R.
Published: July 2010

Tillage methods under irrigated soils in arid or semiarid regions have not been studied extensively. Four methods: chisel plow and one disking (T1), moldboard plow and two disking (T2), rotary tillage only (T3), and no tillage (T4) were used in the present study. A fullseason corn (Zea mays L.) hybrid (Israel variety ‘Neveh Vaar 70’) suitable for both silage and grain was planted on a calcareous clay soil at the College of Agriculture Experiment Station in Bajegah, Shiraz. Final plant stand was 50,000/ha. Plant height was used as an indicator of plant growth. Whole plants were harvested during the milk stage and fresh weights were determined. Greatest growth occurred with method T1. Silage corn yield were 49.7, 46.1, 44.1, and 40.7 mt/ha for methods T2, T2, T3, and T4, respectively.
Relative Susceptibility of Two Common Groundsel (Senecio vulgaris L.) Biotypes to Six s‐Triazines1
Authors: Radosevich S. R. , Appleby A. P.
Published: July 2010

Effects of several s‐triazine herbicides were studied on common groundsel (Senecio vulgaris L.) previously reported to be resistant to two chloro‐triazine herbicides and on the same weed species from a location not previously treated with triazines. Herbicides tested were: 2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine (simazine), 2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine (atrazine), 2‐(sec‐butylamino)‐4‐(ethylamino)‐6‐methoxy‐s‐triazine (GS‐14254), 2,4‐bis(isopropylamino)‐6‐methoxy‐s‐triazine (prometone), 2‐(tert‐butylamino)‐4‐(ethylamino)‐6‐(methylthio)s‐triazine (terbutryn), and 2,4‐bis(isopropylamino)‐6‐(methylthio)‐s‐triazine (prometryne). The sensitive plants became chlorotic and died when treated with a triazine herbicide. Resistant plants never exhibited these symptoms. Plants of the sensitive biotype were effectively controlled by 0.5 ppm of atrazine or simazine, 1 ppm of GS‐14254 or prometone, or 4 ppm of prometryne. The resistant biotype failed to show any chlorosis or necrosis at the highest rates tested, 4 ppm of simazine and 30 ppm for atrazine, GS‐14254, prometone, and prometryne. Both biotypes were resistant to terbutryn at 30 ppm. These studies showed that resistance in one biotype was not restricted to chloro‐triazines but extended to methoxy‐ and methylthio‐triazines as well. The use of nutrient solutions rather than soil supported the conclusion that resistance is apparently due to physiological differences and not to differences in exposure to the herbicide caused by variation in germination tune, rooting depth, or morphology.
Peanut Accessions Resistant to Seed Infection by Aspergillus flavus1
Authors: Mixon Aubrey C. , Rogers Kenneth M.
Published: July 2010

Peanuts (Arachis hypogaea L.) may become infected with strains of Aspergillus flavus Link ex Fr. that produce aflatoxin, a highly toxic substance when ingested by animals in food or feed products. Development of peanuts with resistance to penetration by the fungus would greatly alleviate the possibility of contamination by the health impairing substance. A new laboratory procedure with conditions conducive to optimum growth of Aspergillus flavus revealed that two peanut accessions were resistant to two toxin‐producing strains of the fungus. Seed with flesh seedcoat color from P.I. 337394 had an average of 5% seed infection for hand‐picked and hand‐shelled samples evaluated at optimum seed maturity in five separate evaluations during 4 years. Also, seed infection for samples of P.I. 337409 averaged 9% for similar evaluation. For two years, comparable checks of two susceptible accessions, P.I. 331326 and P.I. 343419, had an average of 92% and 91% seed infection, respectively, and ‘Argentine,’ ‘Florunner,’ and ‘Wilco 1’ had an average of 34%, 39% and 30%, respectively.
Adaxial and Abaxial Stomatal Resistance of Cotton in the Field1
Authors: Sharpe Peter J. H.
Published: July 2010

An experiment was conducted near Sydney, Australia to determine the adaxial and abaxial stomatal responses of cotton (Gossypium hirsutum L.) to environmental factors under noncycling field conditions. Cotton plants were grown in small lysimeter pans and transpiration was measured by strain guage lysimeters. Leaf temperature, ambient temperature and other micrometeorological parameters were monitored continuously, Stomatal resistances were regularly measured for both surfaces with a diffusion resistance porometer developed by the author.

It was found that under field conditions, the adaxial and abaxial stomata differ in their response to light, water stress, and ambient temperature. Under most conditions, including darkness and. drought, the adaxial surface was considerably higher in resistance than the abaxial surface. However, the differences in resistance between the two surfaces disappeared under a combination of high light and temperature conditions. High transpiration rates and low leaf resistance were associated with high ambient temperatures. With sufficient soil moisture there was no evidence of midday stomatal closure even under severe light and temperature regimes.

It was found that sampling the resistance of one surface alone (particularly the adaxial) did not give an accurate estimate of the overall leaf resistance. In addition, it was also found that similar .resistances on both surfaces under any one set of environmental conditions does not necessarily imply that this will be so under all conditions.
Temperature Influence on the Physiology of Selected Cool Season Turfgrasses and Bermudagrass1
Authors: Watschke T. L. , Schmidt R. E. , Carson E. W. , Blaser R. E.
Published: July 2010

Cool season turfgrasses with rapid photosynthesis, low respiration, and some regulation of growth appear to be best adapted to high temperatures. Foliar and root growth, carbohydrates, photosynthesis in normal and reduced O2 atmosphere, CO2 compensation points (T), and dark respiration rates were determined in two temperature regimes (23 C light‐15 C dark and 35 C light‐25 C dark). Poa pratensis L., P. trivialis L., Lolium perenne L., Festuca rubra L., P. compressa L., and Cynodon spp. were used. Cool season species originating from warm areas grew better and tended to have lower dark respiration at high temperature than those from cooler areas Photosynthesis of cool season species approached that of bermudagrass at high temperature when photorespiration was inhibited by low O2 concentration. Plants with a combination of rapid photosynthesis and low respiration appeared to best supply metabolic demands for carbon. This was reflected by a slower decrease in carbohydrates and growth at high temperature than plants with low photosynthesis and high respiration. T increased in cool season species with increased temperature, and bermudagrass had a low T that was unaffected by temperature changes. T appeared to have some value as an indicator of photosynthetic efficiency between genera of cool season grasses.
Methods of Improving Adhesion of Bermudagrass Sod Late in the Season1
Authors: Burns Robert E.
Published: July 2010

In repairing athletic turfs it is necessary that new sod adhere rapidly and firmly to the substrate to prevent injury. This study was undertaken to investigate methods of increasing the adhesion of bermudagrass (Cynodon sp. var. ‘Tifway’) sod during the fall. Sod plugs (10‐cm diameter) were laid on lightly raked soil periodically from September 2 to November 16 at Griffin, Georgia. Treatments included overseeding with diploid or tetraploid annual ryegrass (Lolium multiflorum Lam.), N, P, and K fertilization, perforating the sod with 1‐cm holes, and covering with perforated clear polyethylene plastic with or without one of the above treatments. After 1 week the force necessary to shear the sod from the substrate was measured. The only treatment to give consistent results was overseeding with ryegrass, which increased adhesion 100 to 200%. The plastic further increased adhesion late in the season. Tetraploid ryegrass was no better than diploid. Due to low adhesion of sod planted on November 9, a subsequent sod (planted on November 16) was permitted to root for 2 weeks. The shear force required was twice that of the November 9 planting. This method would permit sodding of worn areas on athletic fields later than with bermudagrass alone.
Accumulative Effects of Manure and N on Continuous Corn and Clay Soil. II. Chemical Changes in Soil1
Authors: McIntosh J. L. , Varney K. E.
Published: July 2010

Continuous corn (Zea mays L.) was grown on a Panton clay soil (Typic Ochraqualf). Four rates of manure (0, 22, 44, and 66 tons/ha) and five rates of N (0, 56, 112, 168, and 224 kg/ha) were combined in a factorial arrangement and applied each year to the same plots. Also, 120 kg/ha of P and 90 kg/ha of K were applied for 4 years to all plots. Maintenance of structure and fertility had been difficult in this soil. It had not been intensively cultivated even though it lay in large, level fields.

The objectives were to study the effects of the treatments on growth, yield, and nutrient uptake of corn and on the physical and chemical properties of the soil over a period of 5 years (six crops). Results of the first objective have been previously published (7) and effects chemical properties will be reported here.

Cultivation and cropping for 5 years on the check plots reduced organic matter; (by N) 8.7% and OM (by 17.7%. An annual application of 44 tons/ha of fresh dairy cattle manure was needed to maintain soil OM. CEC was increased by manure treatments as would be expected from increase in soil OM.

Soil test results (pH 4.8, NH4OAc extractions) showed that P from manure was more available than fertilizer P; 119 kg/ha of P from manure increased soil test P about the same as 480 kg/ha of P from fertilizer. However, K, either from manure or fertilizer, was readily fixed by the soil (60 to 75% of the applied). More than 414 kg/ha of K was needed to bring K potential in soil to the −3,500 calorie level suggested as adequate for standard free energy of exchange of K for Ca and Mg (13).

Manure application up to 44 tons/ha did not contain enough Ca or Mg to maintain initial levels in the soil. Manure and N treatments had no measurable effects on Fe and Na levels in the soil. Averaged over all treatments, exchangeable Na decreased from 123 to 85 kg/ha and Mn from 45 to 20 kg/ha during the 5 years (1966 to 1971). Treatments of N did not affect rate of breakdown of OM nor decrease pH. The highest rate of N, compared to check plots, slightly increased Mn extracted (by 6 kg/ha). The highest rate of manure decreased extractable Mn (8 kg/ha) and AI (5 kg/ha).

These data showed the value of fresh manure as a soil amendment in addition to its nutrient content. Land applications of manure should be encouraged as a method of disposal but its agronomic value emphasized to encourage use with a minimum of loss.
Effect of Fertility Treatments on the Growth, Chemical Composition and Yield of No‐Tillage Corn on Orchardgrass Sod1
Authors: Lutz J. A. , Lillard J. H.
Published: July 2010

Many data are available on the relative efficiencies of various fertility treatments for corn (Zea mays L.) when grown by the conventional methods of clean tillage. Few data are available, however, on the relative efficiencies of sources and rates of N, P, and K on the growth, chemical composition, and yield of corn grown with the notillage system.

An experiment was conducted at Blacksburg, Virginia, on Groseclose silt loam (Typic, Hapludults; clayey, mixed, mesic) to determine the effects of 168 and 280 kg N/ha, 0 and 100 kg P/ha from partially and fully acidulated rock phosphate, 25 kg P/ha from fully acidulated rock phosphate, and 140 kg K/ha from KCI and K2~SO4 on the growth, chemical composition of leaves and yield of notillage corn on a chemically killed orchardgrass sod.

Growth was significantly slower with the higher rate of N, but significantly increased with increased rates of applied P. Plant growth rate was unaffected by sources of K. Leaf concentrations of N and K were unaffected by rates of N and sources of K, respectively, but the P and K concentrations were significantly increased with the higher P rates. Leaf Mn concentration was higher with the higher rate of N than with the lower rate. The Ca, Mg and Mo concentrations in the leaf increased with P fertilization, but the Zn concentration decreased with P fertilization.

Corn yields were significantly higher with concentrated superphosphate than with partially acidulated rock phosphate applied at the same rate of P. The higher rate of N resulted in a significant reduction in grain yield of 552 kg/ha. There was no response to S in the K2SO4.
Winter Wheat Response to Herbicides Applied Postemergence1
Authors: Robison L. R. , Fenster C. R.
Published: July 2010

Previous research has indicated that herbicides will cause injury to wheat when applied at certain stages of growth. With the development of new herbicides and a complete change in wheat cultivars, work was initiated to determine the cultivar‐herbicide interaction. Twelve different herbicide treatments were applied to five different cultivars of winter wheat (Triticum aestivum L.) at four stages of growth for 3 years at two locations. All plots were kept weed‐free. The stages of wheat growth were fall seedling, spring tillering, boot, and heading. Wheat was most susceptible to injury when herbicides were applied in the boot stage. Wheat also showed considerable injury when herbicides were applied immediately following heading. Herbicide applications in the fall to the seedling stage did not cause as much injury as was expected on the basis of published research. Combinations of herbicides reduced injury below that of the commonly used higher rate of single herbicides. The higher rates of both the ester and amine forms of (2,4‐dichlorophenoxy) acetic acid (2,4‐D) and 3,6‐dichloro.o.anisic acid (dicamba) caused the most injury to all cultivars of wheat.
Sugarbeet Response to Irrigation as Measured with Growth Sensors1
Authors: Johnson Wendell C. , Davis Ronald G.
Published: July 2010

Most research with sugarbeets (Beta vulgaris L) under natural field conditions has been concerned with longterm effects of moisture or fertility levels on overall yield and sugarbeet quality. Variations in ambient conditions under which experiments have been conducted, together with the interrelationships of these variables with each other and with plant factors, have resulted in variable and sometimes contradictory results. There is, therefore, a need for more information on the effects of microclimatic and soil conditions on plant growth. In the study herein, root growth sensors that provide a continuous record of sugarbeet root growth were used to study the short‐term growth response of sugarbeets to irrigation and to variations in ambient meteorological and soil conditions.

The continuous growth records of two typical irrigated sugarbeet roots were compared at Bushland, Texas, during a 48‐day period, June 25 to August 11, 1970, in a record dry season when there was little interference from rainfall on the effect of irrigation on root growth. The roots received 10 cm of irrigation water on staggered dates so that the growth record of a root not being irrigated at a particular time might be used to interpret the growth response to irrigation of the second root. The soil was slowly permeable, requiring an average of about 3 days for free water to disappear after an irrigation. A slowgrowth period of about 3 days in length occurred after each. irrigation during which time the irrigated root grew more slowly than the unirrigated root. When moisture stress was not extreme at the time of irrigation, a temporary decrease in growth rate actually occurred after irrigation.

In general, root growth occurred at night. In the daytime, growth ceased or a shrinkage in circumference occurred which was proportional to the degree of moisture stress. As the need for moisture by the plant increased between irrigations, the increment of nighttime increase in circumference became progressively smaller and that of the daytime shrinkage, progressively greater. By the time the plant showed visual signs of a severe need for irrigation, the net daily growth had approached zero. Some daytime root shrinkage, however, was also noted during the slow‐growth period when the soil moisture content was very high. Although the reasons for the slowgrowth period after each irrigation were not directly determined in this study, logical explanations based on the literature of plant and soil‐water relationships are poor aeration and/or cooling of the soil.
Influence of Straw Application Rates, Plowing Dates, and Nitrogen Applications on Yield and Chemical Composition of Sugarbeets1
Authors: Smith J. H. , Douglas C. L. , LeBaron M. J.
Published: July 2010

Fertilizer N applied at ever‐increasing rates sometimes accumulates in the soil. The practice of fertilizing grain straw with N to stimulate decomposition is questionable, but decomposition of straw immobilizes N that must be compensated for in fertilizing the succeeding crop. Too much N decreases the sucrose content of sugarbeets and decreases sucrose recovery. Experiments were conducted to determine the relative value of early and late straw applications, plowing with N applied in the fall or spring, and the amount of N needed to compensate for straw applications in obtaining optimum beet and sucrose yields with maximum quality.

Sugarbeets (Beta vulgaris L.) were grown following winter wheat (Triticum aestivum L., var. ‘Nugaines’) in 1970 and 1971 on a Pormeuf silt loam soil near Kimberly, Idaho. Straw was applied to the beet plots at rates of 6.7, and 13.4 metric tons/ha, and the plots were plowed either in early September or mid‐November. Nitrogen was applied at 67 kg N/ha in the fall and at 67 and 134 kg N/ha in the spring. The treatments were arranged in a split‐split plot design with 4 replications. Control plots were used with all experiments. N fertilization increased beet, top, and sucrose yields, as well as amino N, Na, K concentrations, and impurity index. It decreased the sucrose percentages of the beets. Straw applications decreased beet, top, and sucrose yields, Na and amino N concentrations, and impurity index, but they did not influence K content of the beets. Early plowing increased sucrose percentage and yield and decreased Na, K, and impurity index. Interactions between straw applications and plowing dates were significant for sugarbeet and beet top yields. Approximately 7.5 kg N fertilizer per metric ton of straw were required to compensate for the deleterious effects of the straw.
Simulation of Drought and Its Effect on Germination of Five Pasture Species1
Authors: Sharma M. L.
Published: July 2010

While studying the effect of drought on seed germination, water potentials are usually simulated by addition of various osmotic substrates to water. Studies showing the comparative effects of these simulated water potentials and of true drought are rather scarce. A study was undertaken whereby drought was simulated by sodium chloride (NaCl)), mannitol, and polyethylene glycol (PEG, 20,000 mol wt.), and its effect on the germination characteristics of Trifolium repens L., Lolium perenne L., Danthonia caespitosa Gaudich, Atriplex vesicaria Hew. ex Benth. and A. nummularia Lindl. was determined. These osmotic drought effects were compared with those of true drought.

The rate and total germination of all the species declined with decreasing levels of water potential. The extent of such reduction varied considerably among species and with the type of osmotic medium. On iso‐potential basis, the order of osmotic medium with respect to the severity of their effect on germination reduction in all the species was PEG > NaCl> mannitol. It was suspected that both NaCl and mannitol entered the seeds, and also that the toxic effects of NaCl were either equally or dominantly offset by the solute entry effects.

Under artificial conditions when soil/seed contact and water flow properties of soil media were nonlimiting and there was no undesirable microbial activity, the equivalence of osmotic‐PEG and matric potential held for all the species under study. Osmotic solutions created by PEG did serve as a convenient and satisfactory media for studying the effect of true drought on seed germination. However, caution must be exercised in extending these results to predict germination behavior in soil/water media where the so‐called “nonlimiting” conditions may not always be met.

The order of species with respect to drought tolerance at germination was: L. perenne > A. nummularia = D. caespitosa > A. vesicaria > T. repens. This tolerance may be a reliable indication for species as regards their ease of germination under comparatively adverse soil/ water conditions. However, it is suggested that it is not necessarily an acceptable index of drought tolerance in mature plants.
High‐Clearance Sprayer for Small Plot Research1
Authors: Seltmann Heinz , Priest Joseph A.
Published: July 2010

A high‐clearance sprayer equipped with compressed air and electronic controls provided a versatile system for small plot research. The large solution tank was replaced with a rack to carry eight (or more) solution tanks each of which could be connected to a separate spray nozzle arrangement. Various combinations of spray rate, solution, and nozzle arrangements were instantly available to the operator
Effect of Applied Nitrogen on the Nodulation and Early Growth of Soybeans (Glycine Max (L.) MERR.)1
Authors: Hatfield J. L. , Egli D. B. , Leggett J. E. , Peaslee D. E.
Published: July 2010

‘Cutler’ soybeans (Glycine max (L.) Merr.) were grown for 6 weeks after emergence in a gravel culture system to evaluate the effects of applied N on nodulation and early growth. Treatments included inoculated plants supplied 10 meq/liter NO3– for 0, 2, 4, and 6 weeks from the time of emergence and uninoculated plants supplied N for 6 weeks. Dry weight of inoculated plants receiving N for 0 and 2 weeks was significantly lower than that of inoculated plants receiving N for 4 and 6 weeks. Dry weight of the stems and leaves was the same for the un‐inoculated plants receiving N for 6 weeks as for the inoculated plants receiving N for 4 or 6 weeks. The number of nodules was increased by the addition of N for 2 weeks following seedling emergence. Total N in the stem and leaves was the same for the inoculated plants supplied N for 4 and 6 weeks as for the uninoculated plants with N. These results provide evidence of the importance of soil N for the initial growth of soybeans, even in the presence of adequate inoculation.
Nutritive Value of Crownvetch Forage as Influenced by Structural Constituents and Phenolic and Tannin Compounds1
Authors: Burns J. C. , Cope W. A.
Published: July 2010

Two experiments were conducted to evaluate the nutritive value of crownvetch (Coronilla varia L.) forage by in vitro dry matter disappearance (IVDMD). Structural constituents [neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (lignin)] and secondary compounds (tannin and phenols) were determined and were related to IVDMD.

In experiment I, leaves were discarded from 40 clones and the stems were separated into tops and bottoms. A regrowth of leafy forage was also harvested. Clonal differences in IVDMD were greater in the stem tissue than in the leaves. Increased quality of crownvetch appeared possible through plant selection; however, selection for increased IVDMD would probably result in late flowering clones that had low spring vigor.

In experiment II, six crownvetch clones varying in internode length, leaflet size, and date of flowering were separated into component parts (stems, leaflets, petioles, and flowers) at different growth stages in different years. Mature stems were considerably lower in percentage IVDMD (47.7) than either leaflets (66.1) or petioles (64.7). However, IVDMD of immature stems was almost equal to those of leaflets and petioles of the same harvest (72.0, 77.9, and 78.9%, respectively). Both cell solubles (100‐NDF) and ADF predicted IVDMD of stems (r2 = 0.96**), while only ADF showed any relation to IVDMD of petioles (r2 = 0.80**) or leaflets (r2 = 0.44**). Total phenol and tannin fractions of leaflets were negatively associated with IVDMD. Total phenols accounted for 59% of the variation, and tannins, 30%. Of the six clones evaluated, highest, but similar, total phenol concentrations were found in leaf tissues of clones 4 and 6. However, IVDMD percentages for clone 6 were not as drastically affected (62.7 to 71.9%) as were those of clone 4 (53.6 to 61.6%). When both structural constituents (ADF) and secondary compounds (total phenols and tannins) were considered, 77% of the variation in leaf IVDMD was accounted for. The importance of the leaf portion in altering the nutritive value of crownvetch is apparent when considering that the total‐plant dry matter, when averaged over the six clones and three harvest dates, consisted of 38.5% leaflets, 45.9% stems, and 10.1% petioles.
Effect of SO4‐S Fertilization on Se Concentration of Alfalfa (Medicago sativa L.)1
Authors: Westermann D. T. , Robbins C. W.
Published: July 2010

Selenium is not required for plant growth, but is necessary for the prevention of white muscle disease and other low‐Se related animal disorders. Areas in the Pacific Northwest that produce forages low in Se are nearly identical to those known to be S deficient. While SO4‐S has been shown to inhibit SeO4‐Se uptake by plants, the effect of S fertilization on Se uptake by plants growing on low‐Se soils where other forms of Se may exist has not been evaluated. This was examined on eight alfalfa (Medicago sativa L.) experimental sites where S fertilization was a variable in southern Idaho. Yields were measured, and plant samples were taken from the first harvest of alfalfa (0.1 bloom) and analyzed for total Se and S, and Se uptake.

Sulfur fertilization significantly reduced forage Se concentrations at four of the eight experimental sites. Forages at seven sites contained less than 0.1 ppm Se before S fertilization, which was further reduced by the S fertilization. The decrease in Se concentration mainly reflected a dilution effect caused by a growth response to the S fertilization. No direct relationship was apparent between forage Se and S levels. This study showed that S fertilization of S‐deficient, low‐Se soils to increase forage production may increase the incidence of Se deficiency in animals. Thus ranchers, cattlemen, and agronomists should become aware of this potential problem and provide protective measures against Se deficiency in their livestock.
Effect of an Asphalt Barrier on Water Storage and Drought Probability1
Authors: Palta J. P. , Blake G. R.
Published: July 2010

Field measurements of water redistribution after infiltration were made on two sandy soils with and without asphalt barriers at a 55 cm depth to determine the barrier effect on soil water potential gradients and on water retention at various times. Estimates of the effect of the barrier on seasonal drought severity and on movement of water to horizons below the barrier were made on one of the soils.

Soil water potential gradients and the volumetric water content at different depths were nearly the same for barrier and nonbarrier plots on Hubbard loamy coarse sand because a coarse sand‐gravel layer between the 25 and 50‐cm soil depths acts as a water barrier. After 96 hours drainage, suctions in Zimmerman fine sand reached 31 cm of water just above the barrier and 61 cm at the same depth without barrier. Available water to barrier depth was increased from 2.9 cm to 7.5 cm by the barrier.

Available water above the barrier was determined for Zimmerman fine sand and was used to calculate the effect of a barrier on drought probability. This analysis showed that on barrier plots, there would be 25 fewer drought days in the driest year in 10, and 31 fewer in the 5 driest years in 10.

Based on rainfall at the Zimmerman fine sand site, it was shown that, over a 3‐year period, supplemental water needed to keep an active growing crop could have been reduced by 58% with a barrier. Probable water loss by percolation, on the other hand, would have been one‐fifth as great with a barrier as without.
Dating Termination of Cotton Irrigation from Soil Water‐Retention Characteristics1
Authors: Grimes D. W. , Dickens W. L.
Published: July 2010

In the semiarid San Joaquin Valley of California, about 90% of the evapotranspiration needs for nonstressed cotton (Gossypium hirsutum L.) are met by irrigation. Soil water‐retention characteristics determine the frequency with which irrigations must be made to replenish depleted soil water during the growing season. Comparatively little attention has been given to using this soil parameter in a predictive sense to help define the correct timing of a final irrigation which may save water and hasten maturity without reducing yield.

Studies were conducted in the San Joaquin Valley, on two soils that have a broad difference in water retention ability, to determine the best irrigation termination date for cotton. A multiple‐regression model that included time of irrigation termination and water‐retention capacity of soil as independent variables was used to describe the influence of these variables on cotton production potential (R2 = 0.71”*). Prepared from the function was a graphic relation illustrating an irrigation termination time that allows a 98% relative yield on the basis of the amount of available water the soil can retain. An optimum irrigation termination time was 28 days later for the low water‐retaining soil of the study than for the high water‐retaining soil. Correct timing of a final irrigation saved water and hastened the opening of mature bolls without harm to lint yield or quality.