bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation in the Plant Environment and Photosynthesis1
Authors: Waggoner Paul E. , Moss D. N. , Hesketh J. D.
Published: July 2010

Synopsis

Chemical theory predicts that an increase in light intensity will increase photosynthesis whenever the quantity of CO2 and turbulence are of the magnitude encountered in the field. Diffusion theory predicts the equivalent effect of increasing turbulence of CO2. In fact photosynthesis of cane increased between 1.2 and 1.6 cal. cm.−2 min.−1 of incandescent light, even at 200 ppm CO2 in calm air. On the other hand, photosynthesis of tobacco and dogwood increased little at sunlight intensities above 0.4 cal. cm.−2 min.−1.
Seedling Emergence of Winter Wheats and Its Association With Depth of Sowing, Coleoptile Length Under Various Conditions, and Plant Height1
Authors: Sunderman Donald W.
Published: July 2010

Synopsis

Highly significant differences were found in the emergence percent and coleoptile length of varieties. Plant height was positively correlated with coleoptile length in 3 of 5 tests and with emergence percent in 1 of 2 tests. Coleoptile length in all laboratory tests was closely associated with average coleoptile length and emergence percent found in the field tests. The laboratory test that gave the best indication of varietal field performance was the vermiculite test at 85° F.
Relation of Root Distribution to Water Uptake and Availability1
Authors: Gardner W. R.
Published: July 2010

Synopsis

A mathematical theory describing water uptake by nonuniform root systems and other factors is developed. The relative distribution of roots with depth and the water retaining and transmitting properties of the soil determine the main features of the water uptake pattern. Other factors such as the total number of roots are relatively unimportant. Good agreement is obtained between the theory and an actual uptake pattern for sorghum.
Use of the Intercept Method in Determining the Calcite‐Dolomite Ratio for Rating Agricultural Limestones1
Authors: Brydon J. E. , Rice H. M.
Published: July 2010

Synopsis

In one convenient analytical procedure, the intercept method gives the CaCO3 equivalent, the proportion of calcite and dolomite and an estimate of the Ca and Mg content in a ground sample of limestone. Once the composition is determined, the sieve size or the minimum percent passing a sieve can be chosen.
Loss of Carotenoids in Stored Commercial and High‐Carotenoid Yellow Corn, Zea mays L.1
Authors: Dua P. N. , Day Elbert J. , Grogan C. O.
Published: July 2010

Synopsis

Significant differences in losses of carotenoids were found between ground and whole corn and between types of corn as affected by time of storage.
Shortwave Radiation in a Corn Crop1
Authors: Allen L. H. , Brown K. W.
Published: July 2010

Synopsis

Near‐infrared and total shortwave radiation were measured at various heights in corn using Japanese EKO solarimeters, with and without appropriate light filters. From these measurements, visible radiation was calculated. The resulting data indicated that the attenuation coefficients for radiation within this crop were not constant. Near‐infrared radiation was found to be a higher percentage of the total shortwave radiation at the bottom of the crop than at the top.
Germination of Fourwing Saltbush Seeds at Different Levels of Moisture Stress1
Authors: Springfield H. W.
Published: July 2010

Fourwing saltbush (Atriplex canescens) is a promising species for seeding Southwestern ranges. Studies were conducted to determine the effects of different levels of moisture stress and temperatures on seed germination. Six sources of seeds were germinated in mannitol solutions under 0.3, 3.0, 7.0, 11.0, and 15.0 atmospheres of osmotic pressure at 85, 63, and 49F.

Total germination in 28 days decreased as moisture stress increased. Germination also was delayed as moisture stress increased, especially at 49F. The seeds germinated better at 63 and 49 than at 85F. Seeds germinated well even under the relatively high 7‐atmosphere level at 63F, which suggests that moisture stress may have less effect on seed germination when temperatures are near optimum. One source germinated better than four of the other five sources under the 11‐ and 15‐atmosphere levels indicating it might germinate more readily under arid range conditions.
Nodulation Responses of Soybeans to Added Phosphorus, Potassium, and Calcium Salts1
Authors: de Mooy C. J. , Pesek John
Published: July 2010

Large and highly significant curvilinear responses in number, weight, and leghemoglobin content of nodules of 5 soybean Plant Introductions to application of P were observed in outdoor pot experiments with 3 nutrient variables and uniform mixing of soil and fertilizers. P × Ca interaction effects were sometimes significant for nodule number and weight. Ca had a strong negative effect on leghemoglobin content. Significant varietal differences in number and weight of nodules and differential responses of nodule weight due to P, P2, and P × Ca were found at 2 stages of development. Between 2 stages of growth, the nodule weight of 1 line among 3 changed from lightest to heaviest, indicating a significant variety × time interaction. Maximum nodulation required very high levels of applied P and K salts. At rates of 400 to 500 pp2m P and 600 to 800 pp2m K, the predicted nodule weight at the end of flowering was tripled. Maximum nodule activity required even higher levels of applied P. The findings reported in this paper not only confirm the dominant role of P fertility for optimum nodulation of soybeans but give a better idea of how high the levels need to be and of the number and weight of nodules which may be produced under good growing conditions.
Evapotranspiration Rates of Field Crops Determined by the Bowen Ratio Method1
Authors: Fritschen Leo J.
Published: July 2010

Simultaneous evapotranspiration rates were determined biweekly for the crop combinations of alfalfa and barley, alfalfa and cotton, alfalfa and sorghum, wheat and oats, and cotton from meteorological data by the Bowen ratio method. The crops were grown under irrigated conditions in the hot, arid region of south‐central Arizona. Calculated evapotranspiration rates ranged from 1.0 to 1.8 times net radiation, indicating that large amounts of energy were extracted from the air mass. Alfalfa prior to cutting tended to use more water than the other crops. Water use by cotton after canopy development approached that of alfalfa. Barley, wheat, and grain sorghum appeared to require the least water.

The Bowen ratio method, as a survey technique or continuous sampling method, can be used to obtain short‐period evapotranspiration rates under field conditions. It appears to be one of the few methods which will yield valid results when crops are subjected to frequent and heavy irrigation or where water tables are present.
Optimum Rates of Seeding Turfgrasses1
Authors: Madison John H.
Published: July 2010

Kentucky bluegrass and ‘Seaside’ and ‘Penncross’ bent‐grasses were sown at 1, 2, 4, and 8 pounds per 1000 square feet and covered 0, ⅛, ¼, or ½ inch. Population was greatly affected by the treatments; chlorophyll index and rooting were not affected. High sowing rate resulted in high populations (13,000–42,000/ft2) of small plants, more susceptible to disease and slower to mature. These populations decreased in the process of maturing. At the 2‐ to 4‐pound rates initial and final populations were not greatly different. At the 1‐pound rate there was little disease, populations were low (900–3,800/ft2) and plants had space to grow and spread, and rapidly reached a larger mature size. This development took time to form a complete cover.

Covering seed ½ inch deep reduced stands of bluegrass slightly, of Seaside up to 60%, and of Penncross up to 75%. Seaside grew well with a cover up to ¼ inch, while ⅛ inch or less resulted in the densest stands of Penncross.

Rapid turf maturity resulted from seeding so there were fewer than 2500–3800 bluegrass seedlings or 5000–8000 bentgrass seedlings per square foot.
Influences of Plant Moisture Stress, Solar Radiation, and Air Temperature on Cotton Leaf Temperature1
Authors: Wiegand C. L. , Namken L. N.
Published: July 2010

The influences of cotton plant relative turgidity (RT), solar radiation (RS), and air temperature at plant height (TA) on leaf temperature (TL,) and leaf minus air temperature (TL — TA) were studied during two crop seasons. The daily data show that (a) a decrease in relative turgidity from 83 to 59% resulted in a 3.6C increase in leaf temperature, and (b) a unit increase in solar radiation (from about 0.5 to 1.5 ly min‐1) resulted in a 9 to 10C increase in leaf temperature. These same changes in relative turgidity and solar radiation resulted in 2.7 to 3.7 and 8 to 10C increases, respectively, in (TL — TA). Seasonal average (TL — TA) was 4C. Leaf temperature and (TL — TA) could be estimated from the seasonal data with an average standard error of 1C by RT, RS, and TA in linear multiple regression analyses. The results of these studies show that variations in plant moisture stress significantly alter leaf temperature and leaf minus air temperature. However, variations in insolation must be carefully monitored under intermittent cloud conditions to account for their influences on plant leaf temperature.
Effect of Soil Temperature, Phosphorus, and Plant Age on Growth Analysis of Barley1
Authors: Power J. F. , Willis W. O. , Grunes D. L. , Reichman G. A.
Published: July 2010

The objective of this research was to assess the influences of soil temperature, phosphorus nutrition, and stage of morphological development upon various growth parameters of barley (Hordeum vulgare L.). Experimental methods consisted of growing barley in a constant temperature growth room at varying soil temperatures and phosphorus levels, harvesting at specific predetermined stages of morphological development, and measuring the rates of dry matter accumulation and leaf area expansion. From these data, various parameters of growth were calculated between consecutive stages of plant development.

Net assimilation rate (NAR) was increased by increased P supply, was independent of soil temperature, and was highest during the flowering period. Leaf area ratio, relative growth, leaf growth rates, and leaf area duration values were also calculated. Leaf area was a linear function of leaf length or length times width. Leaf area duration (leaf area × time) was highly correlated with dry weight over all temperatures, P levels, and stages of plant development. Consequently, any practice that increases either leaf area or the longevity of a green leaf should increase dry weights. These results offer a nondestructive means of estimating dry weights of small grains from measurements of leaf length times width (or length only).
Physiological and Color Aspects of Turfgrasses with Fall and Winter Nitrogen1
Authors: Powell A. J. , Blaser R. E. , Schmidt R. E.
Published: July 2010

Fall and winter N fertilization was studied on bentgrass and fescue to investigate the possibility of maintaining green foliage during winter. Research also involved the effects of this N on top growth, reserve carbohydrates, and photosynthesis.

Desirable turf color was maintained throughout the winter in Virginia latitudes without adverse physiological changes. Green foliage during winter was not the result of residual color from fall but was induced even during the coldest periods of winter. Although no measurable top growth occurred during winter, turf fertilized with high N was very dense.

Reserve carbohydrates generally increased from fall to winter and then decreased slowly until spring when there were sharp declines. Stem carbohydrates varied from 44% dry matter in late fall or winter to 5% in spring. More carbohydrates were found in stems than in leaves and similar trends for sugar occurred in both separates. Higher N rates generally lowered the available carbohydrates, but the opposite was found with certain winter conditions. With determinations made on five dates, net photosynthesis appeared to be higher during winter than spring or summer; however, dark respiration increased with temperatures. Photosynthetic and respiration rates during winter or spring were increased with N fertilization.
Flooding Tolerance of Ladino White, Intermediate White, Persian, and Strawberry Clovers1
Authors: Hoveland Carl S. , Mikkelsen E. E.
Published: July 2010

Intermediate white, ladino white, strawberry, and persian clovers were grown in the greenhouse during a 4‐month period and subjected to flooding 3 days in 10, 6 days in 10, and continuously. In another experiment, three varieties of ladino white and two varieties of intermediate white clover were compared when flooded 6 days in 10 during a 3‐month period.

Ladino clover varieties were more tolerant of poor drainage than intermediate white clover varieties. Persian, strawberry, and ladino white clover herbage growth responses were similar. Root growth of persian and strawberry clovers was less affected by flooding than that of ladino. Herbage N was reduced by flooding in intermediate white and only slightly reduced in ladino, persian, and strawberry clovers. Manganese accumulation in the herbage was not related to flooding tolerance of the clover species.
Reflectance of Cotton Leaves and Its Relation to Yield1
Authors: Thomas J. R. , Wiegand C. L. , Myers V. I.
Published: July 2010

A study was made of the effects of soil salinity, cotton leaf relative turgidity, and Cl content on reflectance and transmittance of radiation by single leaves. The relation of color film density to soil salinity, percentage ground cover, and cotton yield was also investigated. Reflectance from single leaves increased as soil salinity, leaf moisture deficit, and Cl content increased. Aerial photographs of field cotton on saline and nonsaline soils showed greater reflectance from cotton not affected by salt. (Kodak Ektachrome infrared aero film was used.) Multiple regression analyses indicated that under field conditions reflectance measured as film density was influenced by soil salinity and percentage ground cover. Since the same plant and soil factors that affect reflectance from the crop canopy also affect cotton yield, regression equations were calculated to express yield as a function of film density. The regression equations accounted for from 51 to 75% of the variation in yield.
Controlled Release Nitrogen Fertilization of Turfgrass1
Authors: Skogley C. R. , King J. W.
Published: July 2010

Two experimental urea‐impregnated petroleum wax products and prilled urea with a petroleum‐based coating were evaluated as turfgrass fertilizers over a 2‐year period. They were compared with prilled urea, process tankage, and urea‐form. Applications were made to replicated plots of Kentucky bluegrass (Poa pratensis L.)‐red fescue (Festuca rubra L.) lawn turf at rates equal to 0.9, 1.8, and 2.7 kg N per 92.9 m2 in June of 1964 and 1965. Visual turf score ratings were taken every 2 weeks through mid‐October of both years. During 1964 clipping weights were taken each week and the clippings were analyzed for N content. Percent recovery of applied N during a 21‐week period was determined.

Based on turf quality, yield and N content of clippings, and efficiency of N usage, as measured in 1964, the experimental products were superior to the standard materials. One of the urea‐impregnated wax products, X‐419‐68, was superior to all other test products. Plots fertilized with this material, particularly at the heaviest rate, showed improved quality even 11 months after application. Although second‐year results were less dramatic, the experimental products performed well during 1965. Little difference was evident among the experimental materials and urea but they did provide better quality turf than was obtained with most rates of process tankage and all rates of urea‐form.
Influence of Night Temperature on Growth and Development of Cotton (Gossypium birsutum L.). II Fiber Properties1
Authors: Gipson J. R. , Joham H. E.
Published: July 2010

Different night temperature regimes were maintained throughout the boll development period on field‐grown cotton during th 1963, 1964, and 1965 seasons. Decreased night temperatures slowed both rate and amount of cellulose synthesis, which in turn resulted in underdeveloped fiber, characterized by poor physical and chemical properties. In general, ‘Paymaster’ variety appeared to be better adapted to cool nights than Acala variety.
Isolation Requirements for Smooth Bromegrass, Bromus inermis Leyss., as Determined by a Genetic Marker1
Authors: Knowles R. P. , Ghosh A. N.
Published: July 2010

Contamination of seed plots by wind‐borne pollen was studied with a dominant yellow‐leaved mutant. Contamination of borders was considerably greater than that of centres of plots. Borders showed 37.0, 11.1, 1.2, and 0.1% outcrossing at isolation distances of 1, 61, 183, and 732 m, respectively. Average contamination of plots was 9.6, 1.0, and 0.2% for isolation of 1, 61, and 183 m, respectively. Isolation distances of 50 m for Certified seed fields and 300 m for Foundation seed fields appeared ample to maintain strain purity. These distances could be reduced considerably if borders were removed prior to harvest. The marked buffering effect of borders suggested that isolation be disregarded for large fields.
Interaction of Zn and P in Top and Root of Corn and Tomato1
Authors: Sharma K. C. , Krantz B. A. , Brown A. L. , Quick James
Published: July 2010

Interactions of Zn and P in tops and roots of corn were studied in Corning and Landlow soils and of tomato in Corning soil in greenhouse. Zn deficiency symptoms were seen in both crops. The Zn concentration in tops was reduced due to P application and the magnitude of reduction was greatest for the first increment of added P (25 ppm). The Zn concentration in roots was much less influenced by added P. The P concentration was reduced by first rate of 1 ppm Zn and the effect was primarily with higher rates of P. Added P increased P concentration in the top much more than in the roots. In the presence of P, added zinc increased the zinc concentration in corn roots more than in corn tops.
Effect of Row Spacing and Seeding Rate on Forage Production and Chemical Composition of Two Sorghum Cultivars Harvested at Two Cutting Frequencies1
Authors: Koller H. R. , Scholl J. M.
Published: July 2010

Experiments were conducted in 1965 and 1966 at Madison, Wisconsin, to determine effects of row spacing and seeding rate on forage production and chemical composition of 'Piper' sudangrass and 'Sudax, SX‐11' a sorghumsudangrass hybrid, harvested three times at a height of 76 cm or twice at later stages. Row spacings were 17.8, 35.6 and 71.1 cm. Seeding rates were 8.4, 16.8 and 33.6 kg per ha in 1965 and 13.5, 26.9 and 53.8 kg per ha in 1966.

Herbage yields were greater, nitrogen concentration lower, and lignin concentration higher under the two‐cut system. Yields of the cultivars were similar under three cuttings. Under two cuttings, SX‐11 outyielded Piper when both were harvested at the same morphological stage. However, since SX‐11 is later maturing, Piper's rate of forage production equalled or exceeded that of SX‐11 under both managements. Nitrogen concentration was higher and lignin concentration lower in SX‐11 at any given time.

Forage yields in 17.8‐ and 35.6‐cm rows were similar and exceeded that of 71.1‐cm rows. Row spacing had little effect on chemical composition.

Forage production increased as seeding rate increased, particularly in narrow rows. Under three cuttings only, nitrogen decreased and lignin increased at first harvest as seeding rate increased. Seeding rate had no significant effect on chemical composition at second harvest.
Optimum Plot Size and Number of Replications for Estimating Forage Yield and Moisture Percentage1
Authors: Thomas H. L. , Abou‐El‐Fittouh Hosni Ahmad
Published: July 2010

Uniformity trials were conducted with pure stands of three forage species and one mixture of two species. Plot variance decreased with increasing plot size in every case. The relationship was very close and almost completely linear when plot variance and plot size were converted to logarithms. Thus plot size can be used to estimate plot or error variance. In general, increasing replication number reduced error more rapidly than increasing plot size. Using green weight only to estimate dry weight left 10% of the variation in dry weight in error.
Effect and Mode of Action of Latex and Silicone Coatings on Shoot Growth and Water Use by Citrus1
Authors: Malcolm C. V. , Stolzy L. H.
Published: July 2010

Coatings of latex and silicone were applied to potted sweet orange seedlings which were then grown either in the glasshouse or outside. Measurements of growth and moisture usage over a 20‐day period indicated that latex reduced moisture usage significantly in both situations. Growth was not significantly different for the treatment in any one environment. Leaf burn was less on latexcoated plants but distortion of the growing shoot appeared greater than in silicone‐coated and uncoated plants.

Latex coatings applied to perforated Al‐foil achieved considerable reductions in water vapor diffusion without completely covering the individual perforations. It is suggested transpiration reduction may be achieved by reducing stomatal pore size or by actually covering the pore.
Effect of N Supplementation on In Vitro Digestibility of Corn, Sorghum, and Alfalfa1
Authors: Schmid A. R. , Marten G. C. , Roth L. S.
Published: July 2010

The effect of adding urea as a supplemental nitrogen source for rumen microorganisms in a two‐stage in vitro digestion technique was determined with shelled corn Zea mays L., corn fodder, sorghum fodder Sorghum bicolor (L.) Moench and alfalfa Medicago sativa L. as substrates. Digestibility in vitro of shelled corn and corn fodder was greatly increased by urea supplementation. Urea slightly increased digestion of sorghum fodder but had no effect on digestion of alfalfa. Some inhibition of sorghum digestion resulted with the highest level of urea supplementation (15 mg urea per 0.25 g substrate dry matter). The optimum amount of urea supplementation, an amount at which highest digestibility was obtained without inhibiting the digestion of any one crop, was 10 mg urea per 0.25 g substrate dry matter. The need for N supplementation to obtain maximum digestion in vitro of substrates containing large amounts of readily‐available carbohydrates was clearly demonstrated.
Plant Growth‐Evapotranspiration Relations for Several Crops in the Central Great Plains1
Authors: Hanks R. J. , Gardner H. R. , Florian R. L.
Published: July 2010

Lysimeters, which eliminated runoff and percolation below 90 cm, caused about 10 cm of additional water to be available for growth of grain sorghum in 1967. This additional water doubled yields, with an increase in evapotranspiration of only 50%. Evaporation from soil in the lysimeter was only 32% of the evapotranspiration, compared with 50% for the soil surrounding the lysimeter. Evaporation from the soil within a winter wheat crop during the acuively growing period in the spring, was estimated to be 15 and 37% of evapotranspiration for 1966 and 1967 respectively. Evaporation from the soil within the actively growing crop was estimated to be 34 and 20% of the evapotranspiration for oats and millet, respectively. Estimates of the amount of water evaporated from the soil within a crop allowed for estimation of transpiration from measurements of evapotranspiration. This data indicate that production and transpiration are directly related in this dryland area as de Wit (3) suggests.
Evaluating Turfgrasses for Shade Tolerance1
Authors: Wood Glen M.
Published: July 2010

Short‐duration growth chamber and field techniques are described for studying shade tolerance of pot‐grown seedling turfgrasses. Performance of eight selections each of bluegrass and red fescue grown at four light intensities from seed to 8 weeks in a growth chamber was evaluated. Varying light intensities were achieved by growing the grasses on shelves in a step‐like design so that the lowest light level was farthest from the illumination source. The four light levels in the growth chamber were measured at 3,000, 1,500, 500, and 230 ft‐c.

A field study in natural deciduous shade which permitted entrance of approximately 5% of incident sunlight was used to concurrently evaluate 57 strains of Kentucky bluegrass, 1 lot of Canada bluegrass, 1 lot of roughstalk bluegrass, 18 strains of red fescue, 1 hard fescue, and 8 strains (including 3 species) of bentgrass.

Both methods are feasible techniques for evaluating turfgrasses for shade tolerance. The field method has the advantage of concurrent evaluation of large numbers of turfgrasses under natural conditions.

Performance of the red fescues in shade as a group was superior to that of the bluegrasses. ‘Golfrood’ red fescue was the outstanding cultivar and demonstrated superior shade tolerance in both the growth chamber and field.
Plant Density and Yield of Sugar Beets in an Arid Environment1
Authors: Robinson Frank E. , Worker George F.
Published: July 2010

Sugar beets were grown in an arid area under sprinkler irrigation. Populations of 27,000, 108,000, 430,000, and 1,722,000 plants per hectare were obtained with a square grid placement of seed. A mathematical function sucrose yield and plant population density showed the maximum yield at approximately 100,000 plants per hectare.
Runoff Farming in the Desert. III. Microcatchments for Improvement of Desert Range1
Authors: Shanan L. , Tadmor N. H. , Evenari M. , Reiniger P.
Published: July 2010

A technique of utilizing surface runoff from microcatchments was adapted to grow pasture shrubs (Atriplex halimus L.) on a barren saline loessial plain in the desert. The average annual rainfall of the region is about 90 mm. Microcatchments varied in size from 16 m2 to 1,000 m2. Maximum yields were obtained from a 32 m2 microcatchment which produced an average annual yield of 160 feed units/ha/yr, as compared to 5 to 10 feed units/ha, on the untreated plain. Protein yield was about 40 kg/ha. The system costs $5 to 20 per ha to construct and can repay its construction cost within 2 to 3 years. The method is also being adapted to the growing of fruit trees.
Effects of Ammonium Polyphosphates on Yield1 and Chemical Composition of Irrigated Corn
Authors: Adriano D. C. , Murphy L. S.
Published: July 2010

Irrigated corn (Zea mays L.) grown on Zn‐deficient, slightly acid Cass fine sandy loam suffered from increasingly severe Zn deficiency when 40 kg/ha P (80 lb/A P2O5) was applied in a band to the side and below the seed. Zinc deficiency was corrected in the presence of the banded P when Zn was supplied at the rate of 11.2 kg Zn/ha as ZnSO4.

Banded applications of ammonium polyphosphate (APP) in the presence of inadequate Zn tended to induce more severe Zn deficiencies than did similar applications of monoammonium phosphate (MAP). When adequate Zn was supplied, the two forms of P produced comparable plant growth responses and grain yields. Yield depressions noted with the use of banded APP without adequate Zn were associated with higher plant P contents than when the plants were supplied with MAP. High levels of plant P were concomitant with low levels of Zn in the plants. Banded applications of P resulted in higher plant concentrations of P than did broadcast P applications and induced more severe Zn deficiencies.

When Zn was limiting, grain yields tended to decrease with increasing P concentrations in young plant tissues. In the presence of adequate Zn concentration of P in young plant tissues was positively correlated with grain yields.
Fatty Acid Composition of Oil from Pearl Millet Seed1
Authors: Jellum M. D. , Powell J. B.
Published: July 2010

Studies of the fatty acid composition of oil from seed of pearl millet, Pennisetum typhoides (Burm.) Stapf and C. E. Hubb., have permitted comparisons of five extraction procedures, genetic diversity in 65 lines, seed‐size differences, and seed maturation in four inbred lines during two growing periods (early and late). Oil extracted with a nonpolar solvent was different in fatty acid composition compared with oil from extraction procedures using polar solvents. The range in fatty acid composition of 65 pearl millet lines of diverse origin was: 16.7 to 25.0% palmitic, 1.8 to 8.0%s stearic, 20.2 to 30.6%o oleic, 40.3 to 51.7% linoleic, and 2.3 to 5.8% linolenic acid. In one variety, the proportion of linolenic acid of total oil was found to consistently increase as seed size decreased.

A study of oil composition in four inbred lines during seed maturation showed that the most rapid and greatest changes in fatty acid composition occurred during the first 16 days after anthesis. Changes in fatty acid composition were small beyond 24 days after anthesis. The relative amounts of palmitic and linolenic acids decreased during seed maturation, while stearic and linoleic acids increased. Proportion of oleic acid increased during early seed maturation and then decreased. Although large differences in fatty acid composition were found between the early and late season crops during early stages of seed development, the final fatty acid composition of the mature seed was similar for the two crops.
Effects of Leaf Nodal Position on Absorption and Scattering Coefficients and Infinite Reflectance of Cotton Leaves, Gossypium hirsutum L.1
Authors: Gausman H. W. , Allen W. A. , Cardenas R. , Richardson A. J.
Published: July 2010

Cotton leaves from nodes 2 to 6 down from plant apices (basipetally) were used to obtain absolute radiometric data (spectrophotometrically measured diffuse reflectance and transmittance) of adaxial (upper) surfaces of single and stacked leaves over the 500‐ to 2,500‐nm wavelength interval (WLI). These data were used to calculate three optical constants: absorption coefficient, k; scattering coefficient, s; and infinite reflectance, R∞.

Youngest leaves had approximately 10% lower single leaf reflectance over the 750‐ to 1,350‐nm WLI than the older lower leaves. Reflectance of the older leaves slowly but progressively increased 2 to 3% going from nodes 3 down to 6.

Leaves were stacked to measure R∞. Youngest leaves had the lowest R∞ particularly over the 750‐ to 1,350‐nm WLI. R∞ increased approximately 5% for older leaves from the 3rd node. R∞ increased at a slower rate for leaves from the 4th, 5th, and 6th nodes.

Second‐node leaves gave the lowest k over the entire 500‐ to 2,500‐nm WLI; then s greatly increased for leaves from the 3rd node, followed by a smaller but progressive increase in s for leaves from nodes 4 to 6.

Youngest leaves had the lowest k over the 500‐ to 750‐nm visible range, the highest k over the 750‐ to 1,350‐nm earinfrared range and the lowest k above 1,350 nm. Absorption progressively increased in the visible range as leaves aged (nodes 3 to 6), and generally did so above 1,350 nm, but this pattern was inconsistent over the 750‐ to 1,350‐nm WLI.

Leaf water contents were positively correlated with thicknesses (r2 = 95%), and each increased with aging going from node 2 down to 6. The absorption coefficient k was positively correlated with leaf water content over the 1,350‐ to 2,500‐nm WLI.

These results show that leaf age affects the interaction of light with cotton leaves (Gossypium hirsutum L.). As investigations of light interactions within plant canopies advance, more attention will need to be given to optical properties of leaves.
Some Interactions of Ca, Sr, and Ba in Plants1
Authors: Wallace A. , Romney E. M.
Published: July 2010

Short‐term uptake tests (48 hr) disclosed that increasing levels of Ca in solution cultures decreased both Sr and Ba uptake by bush beans and decreased the proportions of them remaining in roots compared with that transported to leaves. Barium uptake was greater than Sr, and the concentration of both of these elements was highest in roots and lowest in leaves. Calcium accumulation was highest in stems and lowest in leaves. Uptake of Sr and Ba by roots showed little temperature dependency, but long‐distance transport to shoots was temperature dependent as is known for Ca. Strontium and Ca and also Ba to a lesser extent served as stable‐element carriers for transport of Sr85 isotope into bush beans, but Mg did not. A level of 10‐2M Ba in nutrient solution was toxic to the plants; that which was transferred to shoots killed the leaves. Its effect on permeability resulted in large transfer of Sr85 to shoots. Long‐term uptake tests (90 days) with tobacco grown in solution culture disclosed that Ca accumulated more in leaves while Sr and Ba accumulated more in roots. Two desert‐plant species, Lycium andersonii and Lycium pallidum, showed interesting differences in their accumulation of these elements. L. andersonii tended to concentrate Ca in leaves, but Ba was concentrated in roots with Sr equally divided between roots and leaves. L. pallidum concentrated all three of these cations more in roots than in leaves.
Seeding Sorghum × Sudangrass Hybrids into Tall Fescue Sod1
Authors: Hart Richard H. , Retzer Henry J. , Dudley Richard F. , Carlson G. E.
Published: July 2010

Sorghum × sudangrass hybrids (Sorghum bicolor L. Moench × Sorghum sudanense P. Stapf.) were seeded into tall fescue (Festuca arundinacea Schreb.) sod, which had been temporarily suppressed with paraquat4 (l,l'‐dimethyl‐4,4'‐bipyridinium dichloride). Sod‐seeded De‐Kalb ‘Sudax SX‐12’, with N fertilizer banded under the seed, produced as much forage as conventionally seeded Sudax. Sod‐seeded ‘Sudax SX‐11’ and SX‐12, with N broadcast at seeding, produced less forage than conventionally seeded Sudax, unless enough paraquat was applied to damage tall fescue permanently. Combined yield of tall fescue and sod‐seeded Sudax, under the best management, was about 60% greater than yields of either fescue or Sudax alone.
Method for Estimation of Tannin in Grain Sorghum1
Authors: Burns Robert E.
Published: July 2010

The acidified vanillin method of tannin analysis, widely used for forage crops, was modified to permit rapid estimation of relative tannin content of grain sorghum [Sorghum bicolor (L.) Moench]. The method involves overnight extraction of ground grain with methanol at room temperature. An aliquot of the extract is added to a solution of vanillin and hydrochloric acid and the resultant color is read on a colorimeter at 500‐525 mµ The reagent is specific for astringent compounds in plants and the results were highly correlated with digestibility.
A Sunfleck Theory for Plant Canopies I. Lengths of Sunlit Segments along a Transect1
Authors: Miller E. E. , Norman J. M.
Published: July 2010

The size distribution of sunflecks under a plant canopy can be represented by the length distribution of sunlit segments along a straight‐line transect drawn under the canopy. A mathematical connection is deduced between this sunlit‐length distribution and the probability, as a function of length, that a short line placed randomly under the canopy will be everywhere in sunlight. In turn, this probability distribution is deduced for randomly‐placed leaves, from which the above‐mentioned connection yields the desired sunlit‐length distribution. In subsequent papers this basic result will be used to predict the effect of penumbra — fuzzy shadow edges caused by the finite angular size of the sun — upon the light intensity distributions within or beneath canopies, as a function of leaf size, shape, height, density, and orientation.
Forage Characteristics Limiting Animal Performance on Warm‐season Perennial Grasses1
Authors: Duble R. L. , Lancaster J. A. , Holt E. C.
Published: July 2010

Chemical and in vitro characteristics of six perennial summer grasses {common, ‘Coastal’ and ‘Coastcross‐1’ bermudagrasses [Cynodon dactylon (L.) Pers.]; ‘Pensacola’ bahiagrass [Paspalum notatum Flugge]; common weeping lovegrass [Eragrostis curvula (Schrad.) Nees.]; and ‘Kleingrass 75’ [Panicum coloratum L.]} were determined to identify factors limiting the performance of grazing animals. In vitro dry‐matter digestibility (IVDMD), cell wall content (CWC), acid‐detergent fiber (ADF), acid‐detergent lignin (ADL), silica, and in vitro cell‐wall digestibility (IVCWD) were determined for samples of available forage taken at 14‐day intervals. Animal performance was obtained from yearling heifers grazing established stands of each grass. Available forage was estimated from strips harvested from each pasture at 2‐ to 4‐week intervals. Animal performance was significantly correlated (r = 0.85**) with available forage when dry‐matter digestibility was relatively uniform. As IVDMD of available forage decreased, more available forage was required to reach maximum average daily gain (ADG). Also, as IVDMD decreased, maximum ADG decreased. The CWC of the grasses ranged from 45 to 82% with cell wall digestibility ranging from 82 to 36%, respectively. CWC and IVDMD were significantly correlated with animal performance (r = —0.80**, and 0.78**, respectively). Cell wall digestibility calculated from Van Soest's “summative equation” significantly over‐estimated IVCWD. Lignification was one factor limiting cell wall digestibility (r = —0.76**) and in Coastcross‐1 bermudagrass and Pensacola bahiagrass silica was as important as lignin. CWC and IVCWD could be used to accurately predict IVDMD in Kleingrass 75 (r = —0.96** and 0.95** respectively). High lignin and/or silica content of available forage was associated with poor animal perfortnance on all grasses.
Crop Response to Excessive Zinc Fertilization of Alkaline Soil1
Authors: Boawn Louis C. , Rasmussen P. E.
Published: July 2010

The objective of this research was to evaluate the tolerance of economic plant species to excessive levels of available Zn in the soil.

Fifteen field crop and three vegetable crop species were grown under uniform conditions in a growth chamber in alkaline soil treated with 10, 100, 200, 300, 400, and 500 ppm Zn. Response was evaluated in terms of dry matter yield decrease (YD) and Zn concentration in tops. Grass species were most sensitive and had maximum YD's greater than 40%. Alfalfa (Medicago saliva L.), Alaska pea (Pisuni sativum L.), tomato (Lycopersicon esculentum Mill.), lettuce (Latuca saliva L.), spinach (Spinacia oleracea), and sugarbeet (Beta vulgaris L.) had YD's between 20 and 40%. Field bean (Phaseolus vulgaris L.), snap bean, russet potato (Solanum tuberosum L.), white potato, clover (Trifolium repens L.), and Perfection pea (Pisum sativum L.) did not undergo a significant YD.

Zinc concentrations in tops associated with a 20% YD ranged from 240 ppm for field bean to 740 ppm for sugarbeet, with most crops falling in a 400 to 600‐ppm range. The most sensitive species tolerated Zn additions of 200 to 300 ppm before undergoing a significant YD.

Crops that underwent a significant YD because of excess Zn were stunted but showed no discoloration, malformation, or necrosis indicative of a direct metal toxicity.
Growth Stages of Sorghum [Sorghum bicolor, (L.) Moench.]1
Authors: Vanderlip R. L. , Reeves H. E.
Published: July 2010

Research with grain sorghum often involves sampling several times during the growth cycle. Samplings often are designated by calendar date, days after planting or emergence, or plant height. Often these bear little or no actual relationship to the morphological or physiological age or status of the plant. Although certain stages of sorghum growth are fairly well established, the growth cycle of sorghum has not been fully described. Therefore, a standard set of growth stages needs to be defined. Based on detailed studies of grain sorghum hybrids of different maturities, the following ten stages of development have been defined and illustrated: emergence, three‐leaf, five‐leaf, growing‐point, differentiation, final leaf visible in whorl, boot, half‐bloom, soft dough, hard dough, and physiological maturity. These stages are suggested as standards to describe the timing of sampling or treating sorghum.
Selenium Accumulation in a Collection of Atriplex Species
Authors: Davis A. M.
Published: July 2010

Stone native American Atriplex species are known Se accumulators. This study was undertaken to determine the Se accumulation characteristics of some non‐North American species.

Twenty‐three accessions, including 15 species from 8 countries, were grown in Se‐enriched soil in the greenhouse and the Se content of the aboveground portions was determined by AOAC methods. Atriplex canescens James accessions were higher in total Se (160 ppm plus) than the other species tested. All accessions accumulated Se at potentially toxic levels from the enriched soil.
Adaptability of Maize to High Soil Water Conditions1
Authors: Das D. K. , Jat R. L.
Published: July 2010

Maize (Zea mays L.) plants were grown in furrows and ridges in a lowlying sandy clay loam soil under high soil‐water conditions. Root porosities of 44‐day‐old plants were studied. The investigation was undertaken to determine varieties that could adjust to such environment through internal aeration.

Varietal differences were found in the percentage of air space of roots. Plants grown in furrows had higher root porosities than those grown in ridges. Six varieties studied were ‘Kissan,’ ‘Deccan,’ ‘Jawahar,’ ‘Ganga 5,’ ‘Vikram,’ and ‘Sona.’ The first two may adjust better to excess soil water due to greater internal aeration resulting from increased root porosities.
Comparison of Two Simple Methods of Chlorine Analysis in Plant Materials1
Authors: Adriano D. C. , Pratt P. F. , Holtzclaw K. M.
Published: July 2010

Chloride determinations obtained with an automatic Cl titrator compare very favorably with the results obtained using an electrometric method. Extraction of Cl from plant materials with acids can be done either by shaking samples for 10 min or allowing them to stand overnight. One technician can analyze about 40 to 60 plant samples per day with the electrometric method and 80 to 100 plant samples or 100 to 170 soil extracts or water samples per day with the automatic Cl titrator.
Water Relations and Growth of Cotton in Drying Soil1
Authors: Klepper Betty , Taylor H. M. , Huck M. G. , Fiscus E. L.
Published: July 2010

Two 70‐day‐old cotton plants (Gossypium hirsutum L. ‘Auburn 7‐683’) were subjected to a 26‐day drying cycle at the Auburn rhizotron in order to quantitatively study water relations and growth of both root and shoot as the soil dried. Measurements were made of rooting density changes; stem diameter and height increase; and soil water content (neutron meter), soil water potential (thermocouple psychrometer), and plant water potential (pressure chamber). Marked diurnal flurtuations in plant hydration and soil water potential were observed, especially during the middle of the drying cycle. Plant height increase and stem diameter growth slowed drastically after 17 days even though 35% of the root system was in soil wetter than −1 bar and the plant was rehydrating to a water potential of −3 to −5 bars. Plant water potential in the early morning did not equilibrate with the water potential of the wettest horizon of soil.

The pattern of rooting with depth shifted during drying; initially, there were more roots in the upper layers of soil but, as a result of death of old roots in the top layers and production of new roots in the lower horizons of soil, rooting density increased with depth by the end of the drought. Cotton plants grown at the same time in a similar profile that was maintained moist did not show this reversal in rooting density.
“Reductants” Released by Roots of Fe‐Deficient Soybeans1
Authors: Brown J. C. , Ambler J. E.
Published: July 2010

Iron‐stressed (deficient) ‘Hawkeye’ (HA) releases more “reductant” into nutrient solutions than PI‐54619‐5‐1 (PI) soybean [Glycine max (L.) Merrill] roots. These two plants differ in their response to Fe stress and their susceptibility to Fe chlorosis. The objective of this study was to characterize the “reductant” and to determine its role in the uptake of Fe by HA and PI soybeans.

Reducing capacity of the ‘reductant’ was determined by its ability to reduce ferric to ferrous iron. Fe2+ was measured using 2,4,6,‐tripyrldyl‐s‐triazine (TPTZ) to form the color complex Fe2+(TPTZ)2. The reductant compounds were separated using paper chromatography (BAW‐4:1:5) and located on the paper as prussian blue spots after the papers were placed in ferricyanide‐ferrichloride solutions.

Reductant from 16 HA reduced 90 μmoles (Fe3+ to Fe2+) compared to 5 μmoles for PI soybeans. The chelating agents HEDTA and DTPA (3 μmoles) decreased the reducing capacity from 1.8 μumoles Fe2+/ml concentrated reductant to 0.2 μmoles/ml. Adding more reductant partially overcome the interfering effects of the chelating agents.

Adding the concentrated reductant to nutrient solutions increased the amount of Fe~+ iron in solution, but it did not increase the uptake of Fe by the plant. Something other than reductant in nutrient solution appears to be the controlling factor in the uptake of Fe by PI and HA soybeans. We believe the reductant can aid in releasing Fe from chelating agents to the root and that it can maintain Fe2+ in the reduced state in the root. The latter may be its more important role in Fe nutrition.
Water Stress Relations of the Potato Plant under Field Conditions1
Authors: Epstein Eliot , Grant W. J.
Published: July 2010

Potatoes (Solanum tuberosum L.) grown in northern Maine are often subjected to extensive periods of drought. The objective of this study was to examine the physiological response of potatoes to soil water stress.

Relative water content, leaf diffusive resistance, and tuber water potential of two potato varieties were measured under irrigated and nonirrigated conditions. There were pronounced differences in relative water content, leaf diffusive resistance, and tuber water potential as a result of irrigation. Relative water content (RWC) of plant leaves correlated well with soil water potential but poorly with leaf diffusive resistance. The two potato varieties differed in RWC when soil water potential was high.

Tuber water potential correlated well with RWC and soil water potential. Similarity between tuber water potential and the RWC data suggested that the potato plant exhibits water stress when the soil water potential drops below −0.25 bar.
Effect of Nitrogen Fixation by Legumes on Soil Acidity1
Authors: Nyatsanga Titus , Pierre W. H.
Published: July 2010

The objectives of this study were to determine the quantitative effect of symbiotic N fixation on soil acidity and to compare this effect with the theoretical amount of acidity that should be produced on the basis of the excess‐base and N content of the crops. Alfalfa (Medicago sativa L.) and soybeans (Glycine max (L.) Merr.) were grown on two soils in a greenhouse experiment. The amount of acidity that developed was determined by measuring the amounts of calcium carbonate required to bring the pH of the cropped soils back to those of the uncropped. The excess‐base and N contents of the plants were obtained by analyzing the tops, stubbles, and roots of alfalfa and the tops, roots, and nodules of soybeans. The amount of N fixed was calculated from the differences between the total N found in the crops and the nitrate accumulation that took place in the uncropped soils during the experimental period. Some information was also obtained on the uptake of N from one of the soils by growing a nonnodulating strain of soybeans.

Under the intensive cropping in the greenhouse the amount of N fixed by ‘Vernal’ alfalfa, during a growth period of 167 days (3 cuttings) or by soybeans (Glycine max, T201 and T202, U. S. Regional Soybean Laboratory) during a growth period of 67 to 73 days was sufficient to lower the pH of the soils by more than 1.0 pH unit and to require the addition of up to 2000 ppm of CaCO3 to bring the soils back to their original pH.

On the basis of the data obtained, N fixation from an annual yield of 10 metric tons/ha (4.6 tons/acre) of alfalfa would produce acidity in the soil equivalent to 600 kg CaCO3/ha or 535 lb/acre. Relatively good agreement was obtained between the amount of acidity developed in the soils by alfalfa and soybeans and the theoretical amounts calculated from the N and excess‐base contents of the plants. Thus, the acidity produced in soils by N fixation is of considerable significance under certain cropping conditions. It is suggested that it may also have been an important factor in soil genesis and development.