bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro and In Vivo Digestibility and Ad Libitum Intake of Mechanical Mixtures of Forages1
Authors: Monson W. G. , Reid J. T.
Published: July 2010

We determined in vitro digestible dry matter for two legumes (alfalfa and birdsfoot trefoil) and four grasses (smooth bromegrass, timothy, Reed canarygrass, and orchardgrass). Early‐ and late‐cut forage from each species was analyzed by a modified Tilley and Terry two‐stage digestion procedure. One‐third/two‐thirds mixtures were studied in all combinations within species and between each grass and legume. Certain mixtures of grasses and birdsfoot trefoil gave small, but consistent increases in dry‐matter digestibility over that calculated from the weighted mean of the mixture components. Dry‐matter digestibility and ad libitum intake of timothy and birdsfoot trefoil, separately and in mixtures, were determined in a feeding trial with sheep and steers. All forages in the in vivo studies had similar digestibilities. Average intake values of 117, 124, and 136% (timothy alone = 100) were obtained when forage fed was 33, 67, or 100% birdsfoot trefoil.
Rhizome and Tiller Development of Kentucky Bluegrass (Poa pratensis L.) as Influenced by Photoperiod, Cold Treatment, and Variety1
Authors: Moser L. E. , Anderson S. R. , Miller R. W.
Published: July 2010

Two controlled environment experiments were designed to study the effect of photoperiod and a cold treatment on rhizome and tiller development of ‘Merion’ and ‘Windsor’ Kentucky bluegrass (Poa pratensis L.) Evidence is given to support the following conclusions:

A cold treatment is not essential for rhizome formation. Cold treatments increased tillering but reduced the number of rhizomes.

Both initiation and elongation of rhizomes were favored by a 16‐ or 18‐hour photoperiod when compared to a 8‐ or 12‐ hour photoperiod.

Tillering showed little response to initial photoperiod, although more tillers were formed with a 12‐hour than with an 8‐ or 18‐hour photoperiod in one experiment.

Windsor generally produced more and longer primary and secondary rhizomes than Merion but the latter tillered more profusely than Windsor.
Effect of Plant Type and Nitrogen Level on the Growth Characteristics and Grain Yield of Indica Rice in the Tropics1
Authors: De Datta S. K. , Tauro A. C. , Balaoing S. N.
Published: July 2010

Of the various factors affecting nitrogen response in rice, plant form or plant type is particularly significant. Experiments were conducted during two crop seasons to study the N response and the growth characteristics of some traditional leafy tropical indica varieties and two dwarf indicas of improved plant type. Most of the traditional tall varieties lodged at certain growth stages, and yielded the best when 30 to 60 kg/ha N was applied. One of the dwarf varieties developed by the Institute produced progressively higher yields (the highest being 9,477 kg/ha) up to 120 kg/ha N in the sunny dry season. The increase in dry matter production from panicle initiation to harvest was significantly correlated with grain yield.

During the cloudy wet season when the grain yield response to fertilizer N is lower than during the dry season, the dwarf indica variety, IR8, produced 3,480 kg/ha more rough rice than the tall, weak‐strawed variety, Peta, indicating the importance of short stature and culm strength in obtaining high yields.
Evaporation from Drying Surfaces by the Combination Method
Authors: Fuchs M. , Tanner C. B. , Thurtell G. W. , Black T. A.
Published: July 2010

The combination formula which explicitly includes the surface temperature is used to predict the hourly evaporation from a drying bare soil. The formula is valid regardless of the water vapor saturation deficit at the surface, but the measurement of the surface temperature limits its application to surfaces having a welldefined boundary with the atmosphere. Agreement with hourly evaporation measured by lysimetry at the same site was only fair because of a thermal lag in the energy balance of the lysimeter, but very good (within 1%) for the average daily values where the effect of thermal tag is negligible. All combination formulas use an aerodynamic transfer coefficient, which must include diabatic profile corrections unless sensible heat flux density is small relative to evaporation. Eddy correlation measurementS of the sensible heat flux density into the air confirmed the transfer coefficient used. It is finally shown that the additional measurement of the water vapor pressure of the air can be used to relate the actual evaporation to a usefully defined potential evaporation.
Effects of N, P, and K and Their Interactions on the Yield and Kernel Weight of Barley in Hydroponic Culture1
Authors: MacLeod L. B.
Published: July 2010

The role of P and K on the utilization of N by Herta barley (Hordeum distichon L.) was studied in a greenhouse hydroponics experiment. Nitrogen was supplied at concentrations of 10, 50, 100, and 200 ppm, potassium at 10, 50, and 200 ppm and phosphorus at 25, and 100 ppm in factorial combination. Adequate concentrations of P and K were required to obtain response to increasing concentrations of N. Interaction effects of NK and NP on tillering and on yield and kernel weight of grain were highly significant. Although both P and K were essential for normal growth and development, K had the greater influence on the utilization of N in vegetative growth and on yield of grain. Plants harvested at the early vegetative, mid‐vegetative (heading), and mature stages of development showed a yield response to N, P, and K.

Percentages of N, P, and K in tissue below which final yield of grain decreased were 4.0, 0.70, and 4.0, respectively, for plants sampled at heading. These critical nutrient levels obtained from nutrient culture were higher than for barley grown in soil culture.
Relationship between Tissue Zinc Levels and Maturity Period of Field Beans1
Authors: Boawn Louis C. , Rasmussen P. E. , Brown J. W.
Published: July 2010

The number of days from bean planting to harvest maturity is related to the zinc concentration of either leaf tissue or total top at or prior to bloom stage. In two geographical areas and with two bean varieties, optimum maturity period was associated with approximately 20 ppm or more zinc in these tissues. Below 20 ppm, the number of days required to reach maturity increases rapidly. With zinc levels below 15 ppm there was an increase of up to 30 days in the time required to reach maturity.
Formation, Elongation, and Longevity of Barley Root Hairs1
Authors: McElgunn J. D. , Harrison C. M.
Published: July 2010

The root hairs of 1‐month‐old intact barley (Hordeum vulgare L.) seedlings, grown in a growth chamber, were observed at three different constant root temperatures.

Formation and elongation of root hairs were recorded hourly over 24‐hour periods. Death of root hairs was indicated by the use of neutral red; from these data longevity was determined.

The number of root hairs formed was greater at 18 and 26C than at 15C. Formation was periodic, with three maxima and two minima rates. The changes in formation rates did not coincide precisely at each temperature.

Elongation was greater at 26C than at 15C. The elongation rate was constant for each of the three temperatures over a 24‐hour period.

Longevity of root hairs was 40, 45, and 55 hours at 26, 18, and 15C, respectively. A maximum number of deaths occurred 13 to 15 hours after the initiation of the light period.

Phasic formation and death of root hairs may affect diurnal water absorption due to changes in the living and dead root hair areas. Elongation rate may also affect diurnal water uptake, in that elongation rate is affected by soil conditions.
Visual Estimates and Clipping Plot Size for Evaluating the Forage Potential of Small Grain Varieties1
Authors: Atkins I. M. , Merkle O. G. , Pawlisch Paul E.
Published: July 2010

Visual estimates of the forage value of oat and barley strains were compared with forage yields in 1960 and 1961. Correlations between January estimates and forage yields were highly significant statistically but in the range of 0.40 to 0.50**. Combining January estimates with March estimates, and correlating these with total seasonal yields of forage, gave correlations of 0.55 to 0.66**. Values of this magnitude give considerable confidence in visual estimates for selecting desirable forage producing lines in a breeding program. Correlations between independent estimates of two individuals, were from 0.56 to 0.88**. Correlations of forage yields with 5‐rain yields of the same plots were near zero, suggesting that the evaluation of new strains, based largely on grain yields, fails to recover the best forage types.

Forage samples from 0.1858, 0.3716, and 0.7432 m2 were compared in four seasons, 1959‐62. With a few exceptions, correlations of yields of different plot sizes were good. The coefficients of variability for the 0.1858 m2 plots were usually higher than those of the larger plots. With full stands and proper border protection, it appears that small areas can be utilized satisfactorily for determining forage yields of small grain varieties.
Boron Nutrition of Sugar Beet, Cotton, and Soybean1
Authors: Oertli J. J. , Roth J. A.
Published: July 2010

The levels of boron in nutrient solutions suitable for plant growth are highest for sugar beet, (Beta vulgaris) lowest for soybean (Glycine max), and intermediate for cotton (Gossipium hirsutum). In spite of pronounced differences in B tolerance (and also of B requirement), tissue levels at which toxicity symptoms appear are similar in the three species. The species differences are therefore due more to B uptake and growth characteristics than to tissue sensitivity. Chlorotic tissues contain around 1,000 ppm B, necrotic tissues above 1,000 ppm.

Beet yields and beet sugar contents in greenhouse experiments were not affected by B concentrations up to 40 ppm. Thus the sugar beet might be a suitable plant for high B soils, provided the result is not modified in the field by different climatic conditions.

Boron distribution, patterns of B toxicity, leaf venation, correlation between B injury and leaf age all support the hypothesis that within the leaf, B moves largely in the transpiration stream and is accumulated to toxic levels as water is lost to the atmosphere.
Differential Aluminum Tolerance of Winter Barley Varieties and Selections in Associated Greenhouse and Field Experiments1
Authors: Reid David A. , Jones G. D. , Armiger W. H. , Foy C. D. , Koch E. J. , Starling T. M.
Published: July 2010

Thirty cultivars and experimental strains of winter barley (Hordeum vulgare) were grown on acid, aluminum‐toxic soils treated with two rates of lime in greenhouse tests and three rates in field tests. The objectives were to determine if greenhouse tests could be used for certain phases of breeding for Al‐tolerant barley varieties and to find possible new sources of Al‐tolerant germ plasm.

Dry‐weight yields of top and root growth were determined after 7 weeks in the greenhouse. Grain yields were determined from field plots. Correlation coefficients between root and top yields in the greenhouse were 0.93 for the low lime rate and 0.71 for the high rate. Root and top yields at the low lime rate in the greenhouse were highly correlated with grain yield in the field with no lime added (r = 0.77 and 0.66, respectively) but there was no significant correlation between the same measurements at the high lime levels.

Results of these studies indicate that plant populations of barley can be initially screened for Al tolerance in pots of Al‐toxic soil in a greenhouse. Al tolerance is apparently genetically controlled.

Experimental lines derived from backcrossing to A1‐tolerant parents were also tolerant. Selection for A1 tolerance in a mixed population on acid, A1‐toxic soil in the field was demonstrated.
Some Effects of High Salinity on Germination and Emergence of Barley (Hordeum vulgare L. emend Lam.)1
Authors: Donovan T. J. , Day A. D.
Published: July 2010

A number of barley strains with geographical origins similar to ‘California Mariout’ and other commercial varieties were germinated in salinized water and soil cultures in Tucson, Arizona. Of 39 barleys studied, approximately one‐third equalled or exceeded the germination of California Mariout in highly saline cultures. Their emergence in salinized soil followed the same trends as their germination in petri dishes. Most commercial varieties had lower germination salt‐tolerance than California Mariout and the more tolerant USDA introductions.

Differences were observed between strains in germination under saline conditions. For example, 41% of the seedlings of C.I. 3780 had emerged at the end of 7 days when 20,500 ppm of salts were present in the soil solution. Cereal Investigation 3555, a strain with equally good emergence in non‐saline cultures, had only 24% for the same period. However, after 15 days both entries had similar emergence. At moderate salinity levels most barleys had uniform emergence in soil cultures while at higher levels of salinity only the salt‐tolerant barleys produced satisfactory seedling growth. There was a substantial delay in emergence of all barleys in highly saline cultures.
Dieldrin Uptake by Corn as Affected by Soil Properties1
Authors: Beestman G. B. , Keeney D. R. , Chesters G.
Published: July 2010

In greenhouse experiments, dieldrin uptake by corn was determined on A‐ and B‐horizon samples of three soils taken from a Dodge catena and treated with C14‐ dieldrin at rates of 1 and 5 ppm. Corn was harvested 39, 69 and 90 days after emergence. The soil organic C content was inversely related to the concentration of dieldrin in the roots and shoots of the corn, and was related directly to total dieldrin recovery. No relationship existed between dieldrin uptake, CEC, free iron oxide content or types and amounts of clay size minerals. Less than 3% of the dieldrin applied to the soils was translocated into the aerial portions of corn. The concentration of dieldrin in the root tissue was 20 to 80 times greater than in the above ground portions of the same plant.
Ambient Temperature Effects in Infrared Thermometry1
Authors: Jackson Ray D. , Idso Sherwood B.
Published: July 2010

The output signals of two different infrared thermometers deviated drastically when internal console temperatures rose above 48 and 58 C. Internal temperatures greater than 48 C were observed in both instruments on all clear days investigated, rendering one instrument useless during the warmer parts of these days. In addition, one of the instruments also had a temperature‐dependent calibration curve, which introduced severe uncertainties into its accuracy.
A Self‐Propelled Experimental Plot Foragge Harvester1
Authors: Collins K. L. , Rhykerd C. L. , Noller C. H.
Published: July 2010

A self‐propelled forage harvester has been developed at Purdue University for harvesting experimental plots. The major advantages of this harvester are: lower initial and operational cost than presently available equipment on this type; greater maneuverability; easy transportability in a carry‐all or pick‐up truck; an easily controllable ground speed; and a light weight, keeping soil compaction problems to a minimum.
Boron Tolerance of Tall Wheatgrass1
Authors: Schuman Gerald E.
Published: July 2010

The relative boron tolerance of three varieties of tall wheatgrass [Agropyron elongatum (Host) Beauv.], ‘Alkar,’ ‘Largo,’ and ‘Nebraska P. I. 98526,’ grown in nutrient cultures was determined. Alkar was also tested in soil cultures. Boron concentrations responsible for a 50% decrement in growth in nutrient cultures ranged from 33 to 38 ppm water‐soluble B for the three varieties. The B level causing a 50% decrement in growth of the Alkar variety in the soil culture was 46 ppm water‐soluble B in the soil solution.
Foliar Absorption of Urea by Sandblasted Wheat Seedlings1
Authors: Adriano D. C. , Armbrust D. V. , Murphy L. S.
Published: July 2010

One‐month‐old wheat (Triticum aestivum L. sp.) seedlings were exposed to 13.6 m/sec wind velocity and sand at 1 kg/min for different lengths of time in a wind tunnel. Urea solution was foliar applied at different time intervals of up to 4 days after exposure. Total nitrogen content of the tissues decreased as follows: wind plus sand greater than wind alone equal unexposed. There was a strong indication that foliar uptake of urea was greater when the urea solution was applied soon after exposure to wind and sand
Use of a Dead‐Load Technique to Determine Axial Root Growth Pressure1
Authors: Eavis B. W. , Ratliff L. F. , Taylor H. M.
Published: July 2010

The axial root growth pressures generated by cotton (Gossypium hirsutum L.) and pea (Pisum sativum L.) seedlings under different ambient oxygen concentrations were determined by a dead‐load method in which individual roots encased in plaster of paris blocks were loaded differently. Each seedling root could either elongate or not elongate depending on the applied force. The average values agreed well with those reported by Taylor and Ratliff (1969) using a different method.

The average root pressures exerted by cotton and peas in an atmosphere of 21% oxygen and at —l/3‐bar matric potential were 11 and 12 bars, respectively, and individual values ranged from 8 to 15 bars. Root growth pressures were similar at 8 and 3% oxygen with peas. However, a 3% oxygen level reduced the root growth pressure of cotton to 5 bars. No significant differences were apparent between results obtained at —1/3‐ and —l/10‐bar matric potential around the root tips.
Functions for Cotton (Gossypium hirsutum L.) Production from Irrigation and Nitrogen Fertilization Variables: I. Yield and Evapotranspiration1
Authors: Grimes Donald W. , Yamada H. , Dickens W. L.
Published: July 2010

Cotton lint yield, evapotranspiration (ET), and efficiency of water use were characterized with 2nd‐degree polynomials as functions of the quantity of irrigation water and nitrogen applied on two widely different soils. Excessive vegetative plant development at high input levels of irrigation water and nitrogen resulted in production functions for lint yield having negative interaction coefficients. By placing lint yield on a relative basis for the two soils, it was possible to express relative yield as a function of ET with a single quadratic regression equation (R. Y. = −266.4 + 10.72(ET) −0.079(ET)2;R2 = 0.78). Total seasonal ET increased at a decreasing rate with increased water application up to an addition of 119 cm of water during the entire growing season. Peak daily rates of soil moisture depletion were 1.07 cm, occurring near the time when maximum leaf area was attained. Water use efficiency (kg lint per cm of water used) was improved, in some cases, with the addition of nitrogen.
Functions for Cotton (Gossypium hirsutum L.) Production from Irrigation and Nitrogen Fertilization Variables: II. Yield Components and Quality Characteristics1
Authors: Grimes Donald W. , Dickens W. L. , Anderson W. D.
Published: July 2010

Second‐degree polynomials were used to characterize direct yield components, plant height, and certain quality characteristics of fiber as dependent variables on waterand N‐supplied cotton plants. Yield was correlated most highly with the number of flowers and bolls produced.

Yield was correlated positively with plant height (as a measure of plant growth) when all data were considered, but correlated either positively or negatively when only part of the response function was considered.

Fiber length, micronaire, strength, and elongation were influenced more by water supply than by nitrogen.
Initial Competition of Root‐nodule Bacteria on Soybeans in a Field Environment1
Authors: Caldwell B. E.
Published: July 2010

Competitive behavior of three strains of Rhizobium japonicum was evaluated in a soil free of this organism. The three strains differed in their competitive ability. Strain 110 produced 98% of the nodules when applied in combination with strain 38, and 76% when in combination with strain 76. Strain 76 produced 95% of the nodules when applied in combination with strain 38. Results from treatments inoculated with the individual strains indicated that strain 110 produced the greatest fresh weight and greatest bean yield.
Short Wave Radiation on Inclined Surfaces in Model Plant Communities1
Authors: Anderson Margaret C. , Denmead O.T.
Published: July 2010

The paper describes methods for easy calculation of the flux densities of direct and diffuse radiation on inclined foliage in model plant stands. The stands are composed of randomly oriented, constantly inclined, flat foliage surfaces. The calculations require knowledge of the flux densities of direct and diffuse radiation on a horizontal surface above the stand, foliage inclination, foliage area index, and solar altitude.

For direct radiation, the effects of changes in foliage inclination angle on the average radiation receipt by the foliage depend strongly on solar altitude and on season and time of day. Relatively large differences can exist between stands of different foliage inclination. The distributions throughout the day of direct radiation on inclined foliage surfaces in the stand are shown to be quite different from those on horizontal surfaces.

There are only small differences between surfaces of different inclination in the receipt of diffuse radiation, particularly at the top of the stand.

Trial calculations suggest that in the agricultural growing seasons of many temperate regions the daily receipt of direct radiation by the foliage of a stand per unit of ground surface will increase with foliage inclination.

Some problems of modelling energy‐dependent plant processes in stands are discussed.
Differential Response of Cotton and Peanuts to Subsoil Acidity1
Authors: Adams Fred , Pearson R. W.
Published: July 2010

A series of experiments was conducted to compare the effects of subsoil acidity on cotton (Gossypium hirsutum L.) and peanuts (Arachis hypogaea L.). A strongly acid (pH 5.0) Norfolk sandy loam subsoil reduced cotton yield by one‐third in a field experiment but had no detrimental effect on peanut yield. Cotton roots were unable to penetrate the most acid subsoil in this experiment, whereas peanut roots appeared to be undaunted by the acidity. Growth‐chamber experiments with acid Norfolk and Greenville subsoil materials showed cotton root‐growth to be almost completely inhibited by soils that had no apparent detrimental effect on peanut roots Nutrient‐solution experiments showed that cotton roots created a more acid root environment than did peanuts; these experiments also showed that peanuts had a greater propensity for preferential absorption of lower valency ions to the exclusion of higher valency ions. Either or both of these phenomena could explain the greater tolerance of peanuts to low soil pH and its associated high soil solution aluminum.
Influence of Leaf Age, Illumination, and Upper and Lower Surface Differences on Stomatal Resistance of Sugar Beet (Beta vulgaris) Leaves1
Authors: Brown K. W. , Rosenberg Norman J.
Published: July 2010

Stomatal diffusion resistances of sugar beet leaves were calculated from measurements made on photomicrographs of leaf impressions. The impressions were made by spraying a rapid drying acrylic resin on the leaf.

Milthorpe and Penman's (1967) method for calculating stomatal resistances was programed for electronic computer. Resistances were calculated for leaves of different physiological age and for shaded and sunlit leaves. Calculations were also made separately for upper and lower surfaces of selected leaves. Despite the continuous expansion of the sugar beet leaf throughout its life, the Stomatal resistance of similarly exposed leaves was independent of physiological age except for the most immature leaves.

The greater values of stomatal resistance found for older leaves in the lower part of the canopy were attributed to microclimatic differences, including reduced illumination, rather than to changes associated with advancing physiological age.
Water Storage and Drainage under a Row Crop on a Sandy Soil1
Authors: Black T. A. , Gardner W. R. , Tanner C. B.
Published: July 2010

Drainage from the root zone of snap beans grown on a sandy soil was measured by a lysimeter, and calculated from Darcy's law, and by a hydrologic balance equation. At the end of a 60‐day period the Darcy's law calculation gave a 11% higher estimate of the cumulative drainage than the other two methods. Of the 32 cm of precipitation and decrease of 3 cm in water storage from emergence to harvest, evapotranspiration accounted for 17 cm, and drainage for 18 cm. A useful estimate of the drainage from the root zone in sandy soil was obtained from the space averaged capillary conductivity of the soil in which rooting occurred.
Growth, Composition, and Metabolic Responses of Sugar Beet to Preharvest Application of Maleic Hydrazide1
Authors: Wort D. J. , Singh B.
Published: July 2010

Maleic hydrazide, 8 × M−3, was applied to the foliage of mature plants of sugar beet (Beta vulgaris L.). Its effects on growth and various aspects of composition and metabolism were determined 7, 14, and 21 days after treatment. The striking result was a significant curtailment of growth of leaves and an increase in sucrose content of the storage root. Maximum inhibition of leaf growth, 66%, was evident 7 days after treatment. The sucrose content of the roots was significantly larger on all three days of measurement, while protein and total N were considerably less. Higher nitrate and lower nitrite contents paralleled a decrease in the activity of nitrate reductase.

Respiration in both leaves and roots was depressed, but the photosynthetic rate was greater by 49%, 21 days after treatment. The activity of nitrate reductase and transaminase in leaf and root fell 40% and 18% below values in control plants by the 21st day following treatment. Invertase activity was significantly reduced. The activities of glucose‐1‐, glucosed‐, and fructose‐6‐phosphatases; phenyl phosphatase; and ATPase were depressed by treatment. On the other hand, the activities of the enzymes of sucrose biosynthesis, UDPG‐pyrophosphorylase, sucrose synthetase, and sucrose phosphate synthetase, were significantly stimulated.

The responses suggest that “ripening” may be induced and that the late autumn growth, which often occurs at the expense of stored sucrose, may be considerably reduced by the foliar application of maleic hydrazide 7 to 21 days before the sugar beets are to be dug.
A Study of Certain Nutritional Requirements for Tifgreen Bermudagrass (Cynodon dactylon × C. transvaalensis L.) Utilizing a Hydroponic System1
Authors: Menn Wallace G. , McBee George G.
Published: July 2010

Tifgreen bermudagrass was grown under greenhouse conditions on a modified hydroponic system and subjected to various levels of N, P, and K. Characteristic deficiency symptoms were induced for each element being studied. Tissue levels of each element were related to aesthetic value ratings, thus indicating the point at which each elemental deficiency might begin to appear. These relationships lend themselves to predicting the occurrence of nutrient deficiency symptoms in Tifgreen bermudagrass based on tissue analysis.

Noticeable N‐deficiency symptoms occurred as the tissue level dropped below 22,500 ppm. A P deficiency was observed when the content of this element dropped below 2,000 ppm; however, further investigation is needed concerning the effects of P on Tifgreen nutrition. Growth suppression occurred under high P treatments. Appearance of K deficiency symptoms occurred as the tissue level of this nutrient dropped below 18,000 ppm.
Effect of Soil Temperature, Strength, and pH on Cotton Seedling Root Elongation1
Authors: Pearson R. W. , Ratliff L. F. , Taylor H. M.
Published: July 2010

Cotton (Gossypium hirsutum ‘Empire’) seedlings were grown in glass‐fronted boxes in a growth chamber with varying soil temperature, pH, and compaction levels. Root elongation rate increased rather gradually as temperature increased, reaching a maximum at 32 C, then falling sharply as temperature was increased further. The effect of temperature was amplified at low levels of soil strength and at high pH. Temperature interacted with both strength and acidity on root elongation rate, but the effects of soil strength and acidity on roots were exerted independently.
Influence of Simazine on Crude Protein and Cellulose Content and Yield of Forage Grasses1
Authors: Allinson D. W. , Peters R. A.
Published: July 2010

Conditions evaluated the influence of sub‐herbicidal applications of 2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine (simazine) on the crude protein content and yield of several forage cultivars. In the greenhouse significant increases in percent crude protein and, generally, decreases in both dry matter yield and percent cellulose occurred when ‘Kenwell’ and ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.), ‘Climax’ timothy (Phleum pratense L.), common perennial ryegrass (Lolium perenne L.), annual ryegrass (Lolium multiflorum Lam.), an allotetraploid ryegrass (Lolium sp.), and several Lolium‐Festuca synthetics were treated with simazine. Significant simazine × cultivar Interactions occurred. Tall fescue gave increased yields of crude protein without sacrificing yields of dry matter. Under field conditions reed canarygrass (Phalaris arundinacea L.), treated at five nitrogen (N) levels — 0, 56, 112, 224, and 448 kg/ha — was sprayed with simazine at rates of 0, 0.07, 0.14, 0.28, and 0.56 kg ai/ha on two dates. Three harvests were taken. Simazine and N effects were significant (P<0.01) with respect to dry matter yield. Increased levels of crude protein were evident as a result of simazine application in the first harvest and at the high N level in the second. Increased yields of crude protein were obtained at the 224 kg N/ha level as a result of simazine application compared to controls.
Performance of Five Maize Hybrids in Varying Plant Populations and Row Widths1
Authors: Hunter R. B. , Kannenberg L. W. , Gamble E. E.
Published: July 2010

Five short‐season maize (Zea mays L.) hybrids were grown in 91‐cm and 46‐cm rows at populations of 48,000, 62,000 and 72,000 plants per hectare. The five hybrids responded similarly to changes in population density and distribution. All hybrids increased in grain yield with each increase in population and gave small but significant yield increases to narrowing the row width. Leaf area index (LAI) increased with increasing plant population or decreasing row width. The LAI values, even at the highest population, were much lower than those usually reported as giving maximum grain yield. This suggests that for short‐season hybrids the plant densities presently being used under standard production practices are too low to give maximum grain yields or to detect hybrid by population interactions for yield.
A Convenient Method of Placing Radioactive Substances in Soil for Studies of Root Development1
Authors: Jacobs E. , Atsmon D. , Kafkafi U.
Published: July 2010

Aqueous radioactive solution is placed into medical gelatine capsules which are then quickly frozen over dry ice. The frozen capsules are dropped into holes of various known depths, and root growth to those depths is timed by detection of radioactivity in the leaves.
Effects of Time and Height of Cut on Rooting Activity of Merion Kentucky Bluegrass as Measured by Radioactive Phosphorus Uptake1
Authors: O'Donnell J. L. , Love J. R.
Published: July 2010

Radioactive phosphorus provides a means by which the depth and lateral extent of ‘Merion’ Kentucky bluegrass (Poa pratensis L.) rooting can be measured over the growing season under field conditions. Each 15.2‐cm (6‐inch) depth increment, irrespective of the height of cut, was found to have 1.5 to 3 times as much root activity as the increment immediately below it. The depth of rooting activity was least in the spring (May) and increased to a maximum in the fall (October). The relative lateral distribution of root activity for both heights of cut was approximately 62, 27, 8, and 2% of the total activity for each 5.1‐cm (2‐inch) lateral strip from the line of injection. The lateral extent was least in the spring and greatest in the fall. Throughout the growing season there was more total root activity with the 4.4‐cm (1 ¾‐inch) cutting height than with the 2.2‐cm (7/8‐inch) cutting height. In comparison to the radioactive phosphorus method, the physical measurement of roots tends to overestimate the importance of the roots above 20.3 to 25.4 cm (8 to 10 inches) and underestimate the importance of the roots below this depth.
Oxygen Diffusion in the Soil‐Plant System I. A Model1
Authors: Luxmoore R. J. , Stolzy L. H. , Letey J.
Published: July 2010

A model for steady state, isothermal oxygen diffusion into a cylindrical root surrounded by a water film of uniform thickness is proposed. Equations are developed which account for longitudinal oxygen flux through the intercellular gas spaces, radial flux through the water film, and a respiratory oxygen sink which is defined as a function of oxygen concentration.

A method of computer analysis is outlined whereby the law of continuity is applied sequentially to small sections of root, such that the amount of oxygen diffusing into a section is equated with the oxygen diffusing out plus the respiratory consumption. The solution for the model defines a series of oxygen concentrations along the root length. From these data the amount of oxygen consumed in respiration which diffuses into the top of the root (plant aeration) and the amount diffusing radially from the soil (soil aeration) may be calculated, and effects of soil and plant characteristics examined.
Effect of Ethrel on Growth and Yield of Soybeans
Authors: Slife F. W. , Earley E. B.
Published: July 2010

Ethrel sprayed on plants of ‘Amsoy’ 1.12, and 2.24 kg/hectare at six stages of development caused a reduction in plant height, percent three‐ and four‐seeded pods per plant, weight per 100 seed, and yield of seed per hectare. Percent moisture, protein and oil of mature seed were not appreciably affected by the treatments. The anti‐lodging effect of Ethrel is discussed.
Effect of Time and Rate of N Applications on Yield, Nutritive Value Index, Crude Protein, and Nitrate Content of Bromegrass1
Authors: Kin W. K. Look , MacKenzie A. F.
Published: July 2010

The influence of pre‐winter, spring, summer, and fall applications of N on yield and quality of bromegrass was studied over a 12‐month period on two Quebec soils. N applications increased the yield of dry matter, digestible energy (Yield‐NVI), and crude protein significantly (5%) for each increment of 112 kg N/ha. There was no significant difference among pre‐winter, spring, and summer applications of N. Mitscherlich and multiple regression equations indicated that dry matter yield of bromegrass could be increased by rates of N above 336 kg/ha.

N applied prior to any growth period did not affect the NVI of bromegrass but the crude protein and NO3 contents were significantly increased in the resulting harvested material.

N‐fertilized bromegrass at the 336 kg/ha level gave comparable yields of dry matter and digestible energy to alfalfa‐brome pastures.
Differential Response of Navy Beans (Phaseolus vulgaris L.) to Zinc. I. Differential Growth and Elemental Composition at Excessive Zn Levels1
Authors: Polson D. E. , Adams M. W.
Published: July 2010

Saginaw and Sanilac navy beans (Phaseolus vulgaris) were grown at various combinations of high and normal levels of Zn, Cu, Fe, and Mn in sand culture. Saginaw variety grew normally at 5.0 ppm Zn, while the growth of Sanilac was extremely reduced. This difference was manifested in plant height, leaf number, and root and shoot weight. In addition, a differential Fe‐Cu interaction induced by high Cu levels was observed.

These differences apparently were not related to differential uptake or distribution of the nutrients, since the differences in elemental composition of the two varieties did not seem to be of sufficient magnitude to be biologically significant.

The Saginaw‐Sanilac nutrient interaction relationship is proposed as a valuable system for the study of nutrient utilization since these two varieties differ in their tolerance to high as well as low levels of Zn and other unbalanced micronutrient conditions.
Effect of Picloram on Growth and Protein Levels in Herbaceous Plants1
Authors: Baur J. R. , Bovey R. W. , Benedict C. R.
Published: July 2010

We applied 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) to eight species of herbaceous plants 14 days after planting. Analysis of aerial portions 21 days after planting revealed a significant stimulation in fresh weight of corn, sorghum, cotton, cowpea, and soybean treated at from 0.25 to 0.50 ppb, and wheat at 100 ppb. Significant stimulation in dry weight was noted in corn, sorghum, cotton, and soybean at 0.25 ppb, and cowpea at 1.0 ppb. Significant decreases in fresh and dry weight occurred in corn, wheat, and sorghum at 1000 ppb, and all dicot species at 100 ppb. Herbicide treatments had no effect on the dry weights of rice and wheat, or fresh weight of rice. Herbicide treatments caused reduction in soluble protein concentrations in all monocot species and sunflower. Significant increases in soluble protein occurred at 1.0 and 0.25 ppb in cotton and cowpea, respectively.
Characterizing Soil Aeration Under Changing Soil Moisture Conditions for Bean Growth1
Authors: Dasberg S. , Bakker J. W.
Published: July 2010

An attempt was made to evaluate different soil aeration indices as related to plant growth during fluctuations in soil moisture content. Beans (Phaseolus vulgaris var. ‘Dubbele Witte’) were grown in soil at different aeration conditions obtained by changing bulk density (1.30 and 1.38 g cm‐3), irrigation frequencies (3 to 11 days between irrigations), and O2 concentrations at the soil surface (11% vs 21%). Frequent measurements were taken of O2 and CO3 concentrations of the soil air, oxygen diffusion rate (ODR), and redox potential and a continuous record was kept of soil air content by pot weighings.

After each irrigation, the O2 concentration of the soil air decreased to less than 10% and 5%, respectively, for O2 concentrations at soil surface of 21% and 11%. No complete recovery to the soil surface values was obtained, especially with frequent irrigations. The CO2 concentration of the soil air was never high (6.5% maximum) because of the high solubility of CO2 in the irrigation water.

The redox potentials measured did not show any relationship with air content or with 02 concentration. The ODR measurements were quite variable, the mean values per pot all dropped below 0.2 µg cm‐2in‐1 after irrigation.

Vegetative growth and dry matter production were affected strongly by bulk density and irrigation frequency (yields ranged 4 to 16 g dry matter per plant). Total root production was hardly influenced, but the depth of root penetration was affected strongly by these aeration treatments. Lowering the O2 concentration at the soil surface from 21% to 11% had no significant effect on plant growth.

Comparing the measured aeration indices (02 concentration, ODR, and air content), the mean daily air content gave the best correlation with plant growth (r = 0.82). A continuous record of soil air content seems a good index for evaluating aeration under changing soil moisture conditions.
Growth of Cotton Seedlings in Relation to Maximum Daily Plant‐Water Potential1
Authors: Jordan Wayne R.
Published: July 2010

abstract

A pressure chamber technique was used to evaluate the relation between leaf‐water potential (leaf Ψw) and growth of cotton (Gossypium hirsutum L.) seedlings under greenhouse conditions. A water potential gradient of about 5 bars developed from plant top to bottom by early afternoon, but disappeared after several hours of darkness. A diurnal change of about −12 bars occurred during one day of a drying cycle. Maximum leaf ΨW were reached just prior to sunrise. Growth processes depending largely on cell expansion for expression were affected at identical water deficits during the drying cycle. Increases in plant height, in leaf area, and in fresh weight were inhibited when potentials above −8 bars were not reached for a portion of each day. Predawn wilting was not observed until the eighth and final day of the stress period, corresponding to a leaf ΨW of −26 bars.
Differential Responses of Sorghum Varieties to Picloram1
Authors: Scifres C. J. , Bovey R. W.
Published: July 2010

‘Pioneer 820’ seedlings were the most tolerant of seven sorghum (Sorghum bicolor (L.) Moench.) varieties to pre‐ or postemergence irrigation and to postemergence sprays with various concentrations of 4‐amino‐3,5,6‐trichloropicolinic acid (picloram). Response to the herbiside varied widely among varieties. Significant increases in dry weight of Pioneer 820, ‘RS‐625’, and ‘PAG‐665’ occurred when treated preemergence with irrigation water containing 0.5, 1, and 2 ppm of picloram whereas ‘GA‐615’, ‘RS‐671’, ‘Tophand’, and ‘RS‐626’ were reduced in growth by these concentrations. Dry weights of Pioneer 820 and RS‐625 were increased by irrigation water containing .001 to .005 ppm of picloram applied postemergence or when treated with sprays containing 0.035 to 0.7 kg/ha. Tophand was the least tolerant of picloram regardless of method of application. Varieties intermediate in susceptibility to picloram such as GA‐615, RS‐671, and RS‐626 tolerated the low concentrations used with the various treatment methods, but the higher concentrations often reduced seedling growth.
Dryland Evaporative Flux in a Subhumid Climate: I. Micrometeorological Influences1
Authors: Ritchie Joe T.
Published: July 2010

Daily values of the major energy balance components were determined throughout complete growing seasons of dryland cotton and grain sorghum in Central Texas. Daily net radiation was found to be partitioned primarily between evaoprative flux and sensible heat flux. When crop canopies covered at least 45% of the ground surface and plant evaporation was not limited by soil water, daily net radiation was approximately equal to daily measured evaporation. Before a crop cover was established, evaporation was highly dependent on the water content of the surface soil and the fractional crop cover. For both crops, when water was depleted from the soil to the extent that plant evaporation began to be limited, daily evaporative flux decreased within 10 days to approximately half the daily net radiation. Diurnal variation in the evaporative flux during plant water stress was approximately proportional to net radiative flux, with the proportionality principally determined by the degree of soil water availability and the magnitude of the net radiation.

Seasonal variation in the net radiation was influenced primarily by the solar radiation and the surface reflectance (albedo). The seasonal albedo variation depended primarily on degree of plant cover, ranging from 0.055 over practically bare, freshly plowed, black clay soil to approximately 0.23 over a practically complete cover cotton canopy. This result suggests a possibility for water conservation by increasing the surface albedo during the part of the growing season when wet topsoil is exposed to direct radiation. Closer row spacing and higher plant populations should help in achieving this effect.
Serogroups of Rhizobium japonicum in Soybean Nodules Sampled in Iowa1
Authors: Ham G. E. , Frederick L. R. , Anderson I. C.
Published: July 2010

Serogroups of Rhizobium japonicum present in the nodules of soybeans and their relationship to soil properties were studied on 613 nodule samples obtained at 75 locations during 1965 and 1966. The homogenized nodule suspensions were typed serologically by a quick agglutination test using somatic antisera of cultures of R. japonicure representing seven serogroups. Only 2.8% and 1.1% of the nodules tested failed to react with one of the seven antisera in 1965 and 1966, respectively.

R. japonicum serogroup 123 was the dominant serogroup found in soybean nodules on soils below pH 7.5, while serogroup 135 dominated when the soil pH was greater than 7.8. Individual serogroups were related to at least 2 and as many as 6 soil properties. In 1966, 81% of the variation in the occurrence of serogroup 135 was attributed to soil pH. Relating the occurrence of serogroup 135 to all soil properties accounted for 84% of the variation or only 3% more than pH alone. Less of the variation in other serogroups was attributed to soil properties.
Sites of Iron Reduction in Soybean Plants1
Authors: Ambler J. E. , Brown J. C. , Gauch H. G.
Published: July 2010

Reduction of iron (Fe3+ → Fe2+) at the root of Glycine max. (L.) Merrill var. Hawkeye soybean was studied to identify areas of reduction in the root. Sites of iron reduction were indicated by the formation of a Prussian or Turnbull's blue precipitate. This blue precipitate formed whenever the iron in either FeEDDHA or potassium ferricyanide was reduced by the plant. Where FeEDDHA and potassium ferricyanide were supplied together in the nutrient solution, a blue precipitate appeared in epidermal areas. This precipitate appeared in the endodermal areas of the root when FeEDDHA was supplied to the plant 20 hours before placing them in a ferricyanide solution. Reduction was most pronounced between the regions of root elongation and root maturation at both the epidermis and the endodermis. Reducing capacity was greatest in the young lateral diarch roots indicating that these roots contribute significantly to the ability of the plant to take up iron. A reductant which exuded from the roots of an irondeficient plant was capable of reducing approximately 360 µg of inorganic iron. The ability of some plants to reduce iron may partially explain why they can obtain iron from synthetic chelates and can utilize iron in calcareous soils more effectively than other plants.
Molybdenum Accumulation by Forage Plants1
Authors: Jensen E. H. , Lesperance A. L.
Published: July 2010

Molybdenum accumulation by forage plants was affected by its concentration in a neutral soil, by plant species, and by depth to water table. Accumulation by Medicago sativa L. and Festuca arundinacea Schreb. increased 5.2 and 3.5 ppm, respectively, for each kg/ha Mo added to the soil.

Molybdenum accumulation varied significantly among the 25 forages tested. Legumes generally accumulated more Mo than grasses did. Forage from Lotus sp. had the highest concentration of Mo, and Trifolium sp. ranked next in accumulation of this element. Twelve grasses and Carex sp. are classified as low Mo accumulators.

Depth to water table was associated with Mo accumulation during 2 of 3 years. Forage grown where the water table was near the soil surface contained more Mo than where depth to water table was greater.
Evaluation of Rhizobium japonicum Inoculants in Soils Containing Naturalized Populations of Rhizobia1
Authors: Ham G. E. , Cardwell V. B. , Johnson H. W.
Published: July 2010

An important question in current soybean (Glycine max (L.) Merrill) production is whether inoculation is beneficial when seed is planted in soils where effectively nodulated plants have been produced previously. These studies were conducted to measure the effective of inoculating soybeans with commercial cultures of R. japonicum on seed yield and protein percentage when soybeans were grown on soils which had grown nodulated soybeans previously.

Paired samples of different lots of soybean seed taken before and after commercial inoculation with R. japonicum were planted at two Minnesota locations in 1967. More extensive studies were conductedi in 1968 at five locations in cooperation with various inoculant companies. Seed from a common lot was sent to the participating companies to be inoculated. Two treated samples and an uninoculated check were returned from each company. Two samples were treated immediately prior to planting with humus samples from each inoculant company. Three humus cultures of single strains of R. japonicum, selected from the more effective strains in an inoculation study on rhizobia free soils in Minnesota, also were used as inoculants.

Soybean seed yields and seed protein percentage were not significantly increased by inoculating soybean seeds with Rhizobium japonicum at planting time. The uninoculated checks were adequately nodulated by rhizobia which were in the soil from previous soybean crops. Serotyping of single strain inoculants indicated a substantial range of recovery (0–17%) depending on the strain and location.