bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal Response of Grasses Fertilized with Nitrogen Compared to a Legume‐Grass Mixture1
Authors: Schmidt D. R. , Tenpas G. H.
Published: July 2010

Synopsis

Orchardgrass, fertilized with 500 pounds per acre of elemental nitrogen annually, produced the highest 2‐year average forage yields. Compared to the 500‐pound per acre rate, the application of 1000 pounds of elemental nitrogen generally reduced the yields of orchardgrass, timothy, and bromegrass. Grass‐legume mixture yields were higher with timothy than with bromegrass or orchardgrass. Interactions between grass species and treatments and differences between strains within species were significant.
Effect on Corn Yields of Moisture Stress and Stand at Two Fertility Levels1
Authors: Dale Robert F. , Shaw Robert H.
Published: July 2010

Synopsis

The number of days in the period from 6 weeks before to 3 weeks after silking on which corn was under no moisture stress (NSD) was highly associated with yield. Below 40 NSD there was little difference in yields at stand levels of 12,000 and 16,000. Above 40 NSD stand level was of major importance.
Effects of Moisture and Nitrogen Fertilizer on Growth and Water Use by Native Grass1
Authors: Smika D. E. , Haas H. J. , Power J. F.
Published: July 2010

Synopsis

Native grass production and water‐use efficiency were increased by nitrogen ferilization and by greater available moisture supply. Water‐use efficiencies were greatest for the 0‐N and 80‐N treatments when available water supply was 15 and over 20 inches, respectively. Fertilization increased water use only where subsoil moisture reserves were high.
Quality Relationships of Sweet Corn for Processing1
Authors: Andrew R. H. , Weckel K. G.
Published: July 2010

Synopsis

In each of 4 years 14 sweet corn hybrids were harvested at 3 successive stages of maturity. Although quality was not related to yield, it was highly and negatively associated with deviations from 75, 76, 77 and 78% moisture at harvest. An average of 1.5% moisture was lost per day during the canning period with an average of 14.7 thermal units required for each percent of moisture loss. Moisture loss was more consistent when expressed by thermal units instead of calendar days as indicated by the respective coefficients of variability.
Zinc Concentration in Hop Leaves in Relation to Adequate and Inadequate Levels of Zinc Nutrition1
Authors: Boawn Louis
Published: July 2010

Synopsis

Healthy, high‐producing hop plants were found to have leaf zinc concentrations above 15 ppm at bloom stage. Leaves from plants with zinc deficiency symptoms generally had zinc concentrations below 12 ppm. The critical level for zinc is thus indicated to be between 12 and 15 ppm.
Cold Resistance of Potomac Orchardgrass as Related to Cutting Management, Nitrogen Fertilization, and Mineral Levels in the Plant Sap1
Authors: Howell John H. , Jung G. A.
Published: July 2010

Synopsis

Cold resistance development and maintenance by orchardgrass, as measured by indirect methods, was affected to a limited extent by cutting management and levels of nitrogen fertilization. Orchardgrass cut in early bloom was generally more cold resistant than grass cut earlier. Significant negative correlations were obtained between the percentages of the total electrolyte content exosmosed from frozen stubble on 11 fall, winter, and spring sampling dates and the concentrations of potassium, sodium, and calcium in the plant sap.
Effect of Sunlight and Drying on the Inoculation of Legumes with Rhizobium Species1
Authors: Alexander C. W. , Chamblee D. S.
Published: July 2010

Synopsis

Seed of alfalfa and birdsfoot trefoil which were inoculated with Rhizobium were subjected to 0, 1, 3, 5, and 16 hours of sunlight, and O, 1, 2, 3, and 4 weeks of desiccation in a dry soil. Less effective inoculation resulted in some tests when the seed were subjected to 3 or more hours of sunlight or 2 or more weeks of desiccation in a dry soil.
Sod‐Seeding of Annual Forages into ‘Midland’ Bermudagrass (Cynodon dactylon L.) Pastures. I. Species Evaluation1
Authors: Swain F. G. , Decker A. M. , Retzer H. J.
Published: July 2010

Synopsis

Cereal rye and hairy vetch when sod‐sown into Midland bermudagrass provided a well integrated supply of forage in early spring prior to active Midland growth in summer. Rye produced the earliest spring yields and outyielded barley, field bromegrass, ryegrass, and wheat in that order. Vetch produced high mid and late spring yields. Rye and vetch yields were similar when planted on 3 dates between September 22 and October 14, but November 22 plantings resulted in lower yields. A rye‐vetch mixture outyielded either species alone by approximately 76%.
Nodulating and Nonnodulating Soybean Isolines: II. Response to Applied Nitrogen and Modified Soil Conditions1
Authors: Weber C. R.
Published: July 2010

Nodulating and nonnodulating soybean isolines field‐tested for 7 years produced essentially equal N yields when adequate combined N was available. The amount of N fixed symbiotically depended largely upon the availability of soil N, water, or both, and ranged from 1 to 142 pounds per acre, that is, 1 to 74% of the total N uptake, respectively. The amount of symbiotic N fixation decreased rapidly with increases in fertilizer N. Nodule weight, number, and size were directly related to increased N fixation and inversely related to increased increments of applied N. The correlation of symbiotic N fixation with nodule mass was r = 0.9. Except for a severe moisture stress, the nonnodulating line responded linearly to applied N, with 3.2 pounds of fertilizer N equivalent to 1 pound of plant N. Short‐term rotation studies indicated that, when no fertilizer N was used, the residual effect of a nodulated soybean crop in the previous year was 33 pounds of N per acre.
Cotton Responses to Black Plastic Mulch and Irrigation1
Authors: Bennett O. L. , Ashley D. A. , Doss B. D.
Published: July 2010

Field studies were conducted to determine the effect of black plastic mulch with and without irrigation on soil temperature, plant growth, cotton yields, fiber quality, water use, and weed control. All plots received an annual application of 360, 92, and 250 pounds per acre of N, P, and K, respectively. Plastic mulch increased seed cotton yields by 650 to 975 pounds per acre with or without irrigation and significantly increased the amount of cotton harvested early. Irrigation, however, increased yields of seed cotton by more than 1,600 pounds per acre with or without plastic mulch. Plastic mulch reduced rate of soil moisture loss, increased early season minimum soil temperature, accelerated early growth and fruiting of plants, and gave satisfactory weed control without cultivation.
Responses of Potato Plants to Fertilization and Soil Moisture Tension Under Induced Soil Compaction1
Authors: Timm Herman , Flocker W. J.
Published: July 2010

Potato plants were grown 3 different years in noncompacted, moderately compacted, and severely compacted soils. Changes in yield and quality of tubers were measured against different levels of N and P and against soil moisture tension.

Total and U. S. No. 1 tuber yields were affected adversely by compacted soil. Tuber deformity was confined to angular development conforming to the shape of adjacent clods. Second growth and growth cracks in tubers were of no consequence. No consistent change in specific gravity was found.

Neither yield nor quality of the tubers was enhanced by use of N higher than 180 pounds per acre. Addition of P had no appreciable effect. Soil P reserves were high.

Tuber yield and quality in all soils were best when the soil moisture tension was near 0.5 atm. At a lower tension (0.2 atm) enlarged lenticels were more prevalent, and at a higher tension (0.7 atm) the yield and percent of U. S. No. 1 tubers diminished in severely compacted soil. Without proper control of the soil moisture regime in compacted soils, loss in tuber yield and quality could be accentuated.

Neither changes in fertilizer nor irrigation practices alleviated the adverse effects of soil compaction on potato yield or quality.
Effects of Irrigation and Cutting Management on Yield and Botanical Composition of Selected Legume‐Grass Mixtures1
Authors: Ward C. Y. , Jones J. N. , Lillard J. H. , Moody J. E. , Brown R. H. , Blaser R. E.
Published: July 2010

The yield and botanical composition of three forage mixtures were influenced by supplemental irrigation. Response to irrigation was related to the rooting habits of the species used. Under the best cutting management treatments, the average annual yield increases due to irrigation were about 1.2, 3.2, and 3.4 T per acre on the alfalfa‐orchardgrass, white clover‐bluegrass, and ladino‐orchardgrass mixtures, respectively. Maintaining soil moisture tension at or lower than 0.7 atm gave no increase in yield compared with 2 atm tension, except in the white clover‐bluegrass mixture where the increase was 0.3 to 0.6 T per acre.

The effects of irrigation were similar under all cutting managements for the clover‐grass mixtures. The beneficial effect of irrigation on alfalfa‐orchardgrass decreased as cutting frequency increased. Irrigation increased yields of this mixture by about 1.2 T per acre when cut four times annually, but there was no increase when it was cut six times. The combination of supplemental irrigation and frequent cutting reduced the percentage of alfalfa in the stand.

Clover was maintained in the grass stands by supplemental irrigation, but disappeared in unirrigated plots. Allowing grass to grow taller, or cutting to a higher stubble height, reduced the amount of clover in the irrigated orchardgrass and bluegrass stands.
Sample Size for Mower‐Strip Sampling of Pastures1
Authors: Matches Arthur G.
Published: July 2010

During 1962 and 1963 we obtained estimates of herbage yield before grazing from mower‐strips in orchardgrass and Kentucky bluegrass pastures. Mower‐strips were 13 inches wide and ranged from 1 to 10 sample units (4 to 40 feet) in length. A maximum of 10 mower‐strips were harvested within 0.83 acre paddocks of each grass.

Since estimates of σ2 strips and σ2 units in strips varied from year to year, it is suggested that the optimum size of sample for mower‐strip sampling of pastures should be determined each season.

The .95 confidence intervals for herbage yield tended to decrease with an increase in sample size. Confidence intervals and estimates of the variance of an over‐all mean were reduced more by increasing the number of mower‐strips per paddock than from an equivalent increase in number of sample units per strip. If estimates of herbage yield are to be obtained for the purpose of adjusting grazing pressures on pastures, there appears little practical advantage in harvesting more than 7 mower‐strips 16 to 40 feet long.
Local Effect on Fertility of Urine Voided by Grazing Cattle1
Authors: Lotero J. , Woodhouse W. W. , Petersen R. G.
Published: July 2010

A trial was conducted in an attempt to determine the local effect of urine deposited by grazing cattle on the fertility of the affected sward. Cattle were permitted to graze an unfertilized, pure stand of tall rescue at three seasons of the year: fall, spring, and summer. A number of urine spots were selected on each occasion for further study. The vegetative growth on each spot and on a comparable check area was harvested at intervals for a period of up to 2 years following deposition. The effect of urine was then measured as the difference in dry matter yield, %N and %K between the urine‐treated and the nontreated vegetation. Since it is only a minor component of urine, no results are reported for the effect of phosphorus.

The following conclusions might be drawn from the results of this study:

An individual urination affects a roughly circular area with a radius of from 21 to 25 inches. That is, a total of from 9½ to 13 square feet of sward are affected per urination.

The effect is not uniform, but decreases in a linear manner from the center to the periphery of the spot.

The effect of urine decreases quite rapidly with time after deposition. As a result a urination ceases to be of practical significance within, at most, 10 months following deposition.

Both the magnitude of the effect and the rate of decrease of the effect appear to be directly related to the rate of plant growth.

Under conditions prevailing in the southeastern United States, and in the other areas where forage growth and mineral depletion are rapid, the urine returned by grazing cattle would appear to contribute little to the fertility of the pasture as a whole.
Photosynthesis under Field Conditions. IX. Vertical Distribution of Photosynthesis Within a Corn Crop1
Authors: Wright J. L. , Lemon E. R.
Published: July 2010

The vertical distribution of the photosynthetic fixation of carbon dioxide within a crop of corn was calculated from carbon dioxide profile data and transfer coefficients obtained by analysis of windspeed measurements. Infrared analyzers were used to measure the carbon dioxide concentration at several heights within and above the crop. The calculated total fixation for the day was approximately 60 g CO2 m−2 (equivalent to 470 pounds of sugar per acre per day). The results demonstrated the importance of the upper leaves in the fixation of carbon dioxide and showed the increased fixation by the lower leaves during periods of high light penetration. There was some indication that a coupling existed between the level of windspeed and fixation under conditions of high light and relatively low windspeed. With refinement in technique the method could be used to obtain more quantitative estimates of the distribution of photosynthesis in other crops.
Beef Grazing Systems in Piedmont North Carolina1
Authors: Gross H. D. , Goode Lemuel , Gilbert W. B. , Ellis G. L.
Published: July 2010

Ladino clover‐tall fescue, ladino clover‐orchardgrass, ladino‐orchard grazed in rotation with alfalfa, and tall fescue grazed in sequence with Coastal bermudagrass were compared for beef production. Yearling steers and heifers were used as tester animals. Four years' data, using the put‐and‐take system, are summarized. Pure grass pastures were topdressed annually with approximately 200 pounds of nitrogen per acre, in three applications.

Ladino clover‐grass mixtures had a shorter grazing period than ladino‐grass + alfalfa grazed in rotation but afforded higher daily gains. Animal days per acre, gain per acre, and slaughter grade of yearling cattle were similar for these treatments. Pure‐grass pastures supported a longer grazing period, higher stocking rate, and higher per‐acre gain than the grass‐legume treatments. Average daily gain and slaughter grade were lower on the grass swards. Steers gained more rapidly than heifers, but there was no appreciable difference between sexes in financial return.
Osmotic Stress Effects on Wheat Using a Split Root Solution Culture System1
Authors: Meyer Raymond E. , Gingrich Joe R.
Published: July 2010

Responses of wheat seedlings to applications of various levels of osmotic stresses were studied. A split‐root technique was used in an attempt to determine the effect of turgidity on these responses.

Relative turgidity as frequently used may be a reasonable indication of the internal water stress of plants but under certain conditions may prove to be misleading in determining the time at which the plant is affected by stress. The data obtained in this study indicate that a water stress on the roots may not affect the plant turgidity under low evaporative conditions until relatively high stresses are obtained. Under these conditions relative turgidity would be a poor measure of plant response.

The increase in percentage of dry matter of the shoots appeared to reflect the osmotic stress applied to the roots after a period of time but responded slowly. Dry matter percentage of the roots increased more quickly in response to a stress and also reflected the amount of stress applied.

Phosphorus and nitrogen percentages were decreased in the entire plant by an osmotic stress. The sharp decrease apparent after 24 hours at the 1 bar stress indicated that uptake of these elements must have decreased immediately after application of the stress with dry matter production being essentially unchanged.

The responses to stress almost certainly would be different if the evaporative demand was increased. Time studies appear to be helpful in evaluating investigations of this type.
Influence of Some Environmental and Management Factors on the Persistence of Ladino Clover in Association with Orchardgrass1
Authors: Blake Carl T. , Chamblee D. S. , Woodhouse W. W.
Published: July 2010

The objectives of this study were to determine the influence of different cutting managements, irrigation, simulated drought, fungicide‐insecticide applications, and partial shade on the persistence of ladino clover grown in association with orchardgrass.

Diseases and/or insects were dominant factors influencing persistence and yield of ladino clover. During the second and third years, clover produced three times more forage on areas treated annually with several fungicideinsecticide applications than on the untreated check. The only disease of any consequence noted on the ladino during the investigation was caused by an unidentified virus or viruses.

Limited water supply appreciably reduced yield and persistence. Irrigated clover yielded only 15% as much in the third year as in the first year. A large reduction in yield was also noted under irrigation in the second year, which meant that factors other than moisture were responsible for the lack of persistence of ladino in the area. In addition, ladino was not shade tolerant. In mixture with orchardgrass, the ladino clover component was essentially eliminated in the middle of the second year when grown under slat houses which intercepted approximately one‐third of the incident light. Unshaded ladino grown with orchardgrass produced nearly 500 pounds per acre of clover in each of the second and third seasons. Orchardgrass was not affected by light interception under the same conditions.

A defoliation schedule of cutting clover which was 6 inches tall to a height of 3/4 inch was more favorable for growth and persistence than either the more lenient schedule, 10 inches to 2 inches, or the more severe, 4 inches to 3/4 inch.

Ladino clover produced the lowest yield under the drought conditions created by intercepting approximately 20 inches of the rainfall in combination with 4 inches to 3/4 inch cutting management system.
Comparison and Evaluation of Laboratory Methods of Obtaining an Index of Soil Nitrogen Availability1
Authors: Keeney D. R. , Bremner J. M.
Published: July 2010

An evaluation of incubation and chemical methods of obtaining an index of soil N availability showed that incubation procedures involving estimation of the total mineral N produced on incubation of soil under aerobic conditions at 30C for 14 days or estimation of the ammonium N produced on incubation of soil under waterlogged conditions at 40C for 7 days provided a good index of the availability of the N in Iowa soils to ryegrass. It also showed that the results obtained with these soils by a chemical procedure involving estimation of the N extracted by boiling water and potassium sulfate solution were closely related to N uptake by ryegrass and indicated that this procedure deserves consideration as a routine method of obtaining an index of soil N availability. Air‐drying and air‐dry storage of soil samples had marked effects on the results obtained by the incubation methods studied, but had little effect on the results obtained by the chemical methods found to provide a good index of soil N availability.
Salt Tolerance of N. Co. Varieties of Sugar Cane. II. Effects of Soil Salinity and Sprinkling on Chemical Composition1
Authors: Bernstein Leon , Clark R. A. , Francois L. E. , Derderian M. D.
Published: July 2010

The sugar and mineral contents of ‘N. Co. 293’ and ‘N. Co. 310’ sugar canes, grown at graded salinity levels in greenhouse soil cultures and artificially salinized field plots, were affected differently in the two experiments. Salinity decreased pol percent in the greenhouse cane, which had normal sugar content, but increased the pol percent in the field plots where the cane had abnormally low sucrose. However, even in the greenhouse, reduced cane growth was four times more important in reducing sugar yield than was the reduction in sugar content. The mineral content of cane was increased by salinity, and the increase was more striking in the greenhouse because controls were abnormally low in salt. Overhead sprinkling with saline waters in a greenhouse experiment resulted in very little foliar absorption of salt, equivalent to less than the salt absorbed by cane grown in nonsaline plots in the field.
Influence of Brown Stem Rot on Agronomic Performance of Soybeans1
Authors: Weber C. R. , Dunleavy J. M. , Fehr W. R.
Published: July 2010

Abstact

The performance of six soybean varieties was evaluated on brown stem rot (Cephalosporium gregatum) infested and noninfested soils for 3 years at Ames and 2 years at Cresco, Iowa. Three varieties, corresponding to early, midseason, and late maturity, were used at each location. The use of corn yields as an index of soil productivity level appeared to be a useful technique for measuring effects of the disease where infested and noninfested areas were near, but not adjacent to one another. Soybeans grown on infested soils at the two locations averaged 1 inch taller, 2 days earlier in maturity, 8% less susceptible to lodging, 0.1 gram per 100 seeds smaller in seed size, 10.4% lower in seed number, and 2.0 cwt per acre (11.0%) lower in yield than soybeans grown on noninfested soil. Largest seed yield reduction from brown stem rot occurred in later maturing varieties and may be the result of the length of time plants are diseased and of increased disease severity. About 94% of the yield loss was from seed number reduction, with 6% attributable to seed size reduction. Since there is no appreciable resistance to brown stem rot, evaluation of soybean varieties should be conducted on noninfested soil to permit maximum expression of their genetic potential.
Effect of Bacterial Pustule on Closely Related Soybean Lines1
Authors: Weber C. R. , Dunleavy J. M. , Fehr W. R.
Published: July 2010

Agronomic and chemical performance of closely related resistant and susceptible soybean lines was evaluated in the presence of bacterial pustule (Xanthomonas phaseoli var. sojense (Hedges) Starr & Burk.) The mean difference in bacterial pustule score between resistant and susceptible lines was 1.7. With these moderate disease conditions, the average seed yield reduction in the susceptible lines was 4.3%, of which 86% was attributed to reduced seed number and 14% to reduced seed size. On a linear basis, there was a seed yield reduction of 49.8 kg/ha (2.1%) for each unit increase in pustule score. Height, lodging, maturity, protein, and oil percent were comparable in the resistant and susceptible lines.
P32 Detection of Geomagnetotropism in Winter Wheat Roots1
Authors: Woolley D. G. , Pittman U. J.
Published: July 2010

A tracer technique using radioactive phosphorus (P32) was used to measure root distribution under young winter wheat plants grown in crocks.

Significantly higher (P<0.05) levels of beta activity were found in seedlings where soil wedges containing P32 were oriented to the north or south side of the plants than to the east or west side. Since activity was related directly to P32 uptake by the plants, this would indicate a greater root concentration in the soil on the north and south sides of the seed than elsewhere. This differential root distribution has been described as a geomagnetotropic response.
Effect of Long‐Term Fertilizer Application on Exchangeable and Acid Soluble Potassium1
Authors: Paterson J. W. , Richer A. C.
Published: July 2010

The movement of K within the soil profile of several Jordan Plot soils was studied. Samples from 6‐inch depth intervals (to 36 inches) from plots treated with excess lime, manure, and commercial fertilizer were analyzed for exchangeable and acid soluble K, and the data were compared with those from untreated plots of both limed and unlimed tiers.

Long‐term applications (77 years) of manure and of commercial K fertilizer (KCl) significantly increased exchangeable K to depths of 12 and 24 inches, respectively. The same treatment significantly increased the amount of acid soluble K in the soil to depths of 6 and 12 inches, respectively. Neither exchangeable nor acid soluble K was influenced by excess lime treatments compared to the untreated plots.
Nitrate Content of Fall‐Sown Rye, Wheat, and Oat Forages1
Authors: Moeller W. J. , Thurman R. L.
Published: July 2010

The objective of this study was to compare the nitrate accumulation in the fall forage of oats, wheat, and rye at five rates of nitrogen fertilization. Rye accumulated the highest amount of nitrate nitrogen with lesser amounts for wheat and oats. In general, the nitrate content of rye, wheat, and oat forage increased with increased rates of nitrogen. The first cuttings contained the highest amount of nitrate nitrogen and may have contained sufficient nitrate to present problems to livestock in grazing the forage. The later cuttings and regrowth cuttings were lower in nitrate, with the exception of one date in which the cutting was done after an adverse weather period.
On Higher Education, Agriculture, and Soil Science in Turkey1
Authors: Kroontje Wybe
Published: July 2010

Some aspects of American (Land‐grant) and Continental European educational philosophies important to university development in Turkey are described. In view of limited resources available and great demands for trained personnel it is suggested that before changing curricula in agriculture and soil science from 4 to 5 years the following alternatives be considered: (1) lengthening the semester period,. (2) introducing a summer session, and (3) establishing a graduate course of study. Stationing of research personnel of the Ministry of Agriculture at the universities is recommended and the appointment of extension specialists to the Faculties of Agriculture advocated. Coordination of activities and resources of national and international academic and professional communities is necessary if not mandatory to avert famines in many parts of the world.
Residual Effect of Large Applications of Phosphorus on High Phosphorus Fixing Soils1
Authors: Kamprath E. J.
Published: July 2010

abstract

Large initial applications of P to high P‐fixing soils had a marked residual effect on the yield of corn (Zea mays L.) 7 to 9 years after application. On a Georgeville soil very low in available phosphorus, an initial application of 612 pounds of P per acre 9 years earlier was still supplying sufficient P for high corn yields. Response of corn to 22 pounds of P per acre applied in a band was significantly affected by the P applied 8 and 9 years earlier. Similar results were found with the P uptake by corn grain. Above 8 ppm of available soil P (0.05N HCl + 0.025N H2SO4, extractant), there was no further increase in corn yields. For high corn yields on high P fixing soils, the entire root zone rather than isolated bands should have a high level of P.
Trifluralin Behavior in Soil. I. Toxicity and Persistence as Related to Organic Matter1
Authors: Bardsley C. E. , Savage K. E. , Childers V. O.
Published: July 2010

The incorporation of either the alkali‐extractable colloidal fraction of leonardite or activated charcoal in mineral soils of low organic matter content resulted in increased toxicity to barley and cucumbers from surfaceapplied trifluralin. Linear or nearly linear responses were obtained up to 6.0% O. M. at 41, 43, 81, and/or 93 days after application of treatments. Subsurface application of trifluralin resulted in no increase in toxicity with increasing rates of charcoal at 43 days, but a significant increase was found at 93 days at the 6.0% O. M. level. GR50 values for O. M. in soil ranged from 4.6 to 11.0 for surfaceapplied trifluralin. Correlation coefficients for reduction in plant growth versus O. M. rates were generally high.

It is indicated that the increased trifluralin toxicity with increased organic matter in the soil is due to greater retention (adsorption) of the vapor phase of the herbicide and that this toxicity can persist up to 93 days from application.
Rye Seeded for Grain in Coastal Bermudagrass1
Authors: Welch L. F. , Wilkinson S. R. , Hillsman G. A.
Published: July 2010

A 3‐year study compared rye (Secale cereale L.) grain and ‘Coastal’ bermudagrass (Cynodon dactylon L.) forage yields with cropping systems of Coastal only, rye only (conventional seedbed), and Coastal‐rye (rye seeded in Coastal). Five rates of N were added for rye and two rates of N were added for Coastal.

Sod‐seeded rye yielded as well as conventionally seeded rye. First‐harvest Coastal yields were lower with Coastalrye than with Coastal only. This reduction in Coastal yield increased as the rates of N added for rye increased. Annual Coastal yields, averaged over all rates of N added for rye, were as high with Coastal‐rye as with Coastal only for 2 of the 3 years.

Light intensity, soil water, and soil temperature were lower with a high rate of N added for rye than with a low rate. All of these factors probably contributed to the low first‐harvest Coastal yield, but shading of Coastal by the rye grain crop is suggested as the dominant factor.
Mode of Response of Weed‐Free Corn to Post‐Planting Cultivation1
Authors: Prihar Sohan S. , Van Doren D. M.
Published: July 2010

Maximum corn grain yield increase associated with post‐planting cultivation of weed‐free corn on a soil susceptible to crusting was 1,790 kg/ha or 25% of mean yield. The maximum contribution of increased water infiltration was 770 kg/ha. The remaining causes of yield increase associated with stirring the soil surface were not unequivocably established. Oxygen diffusion rates at 10‐cm depth were essentially unaffected by cultivation. Cultivation reduced short term evaporation from the soil surface 30 to 45% and resulted in a twofold to sixfold increase in root weights between corn rows to a depth of 23 cm.
Effect of Time and Depth of Sampling upon Soil Test Results1
Authors: Childs F. D. , Jencks E. M.
Published: July 2010

Available phosphorus, potassium, pH, and lime requirement determinations were made for 13 consecutive months in Gilpin, Gilpin‐Upshur, and Westmoreland soils under permanent pasture. Statistically significant differences in available phosphorus and potassium and lime requirement occurred with time with the largest seasonal differences occurring between the winter and summer months. Differences found were of sufficient magnitude to influence lime and fertilizer recommendations.
Phytotoxic Phenolic Compounds in Sericea Lespedeza Residues1
Authors: Langdale George W. , Giddens Joel E.
Published: July 2010

Sericea lespedeza (Lespedeza cuneata) stem residues incorporated into soils were effective in depressing corn growth.

Four phenolic compounds—protocatechuic acid, vanillin, ferulic acid, and p‐coumaric acid—were detected by thin layer or gas chromatographic techniques in sericea residues. Stems contained the greatest amount of these compounds.

Higher concentration of protocatechuic acid than other phenolic compounds was detected. The protocatechuic acid appeared to be less effective in inhibiting auxin activity of indoleacetic acid in Avena coleoptiles than the smaller concentrations of vanillin, ferulic acid, and p‐coumaric acid.
Percent Soil Cover by Six Vegetative Mulches1
Authors: Greb B. W.
Published: July 2010

Estimates of percent soil cover by straw or stalk type vegetative mulches can be calculated by means of measuring the average length, diameter, and weight of a random sample of clean, oven‐dry material. Efficiency of soil cover per unit weight for mulches at Akron, Colo., were spring barley > winter wheat = spring oats > sudangrass > grain millet > grain sorghum.
Nitrate Accumulation in Tobacco Leaves in Relation to N, P, and K Concentrations of the Leaf1
Authors: Peterson L. A.
Published: July 2010

Nitrate accumulation in tobacco leaves was studied in relation to the N, P, and K concentrations of the leaf. The leaves used in the study were from a 3‐year N, P, K fertility trial and possessed wide variations in concentrations of N, P, and K. The importance of the N concentration as well as the unimportance of P and K on nitrate accumulation were shown. Nitrate N and total N contents of the leaves correlated at a highly significant level.

About 60% of the variation in the nitrate N content of the tobacco leaves was accounted for by the amount of N, P, and K added as fertilizer. The amount of added N was the major contributing factor in the correlation.
“Runoff Farming” in the Desert: II. Moisture Use by Young Apricot and Peach Trees1
Authors: Cohen O. P. , Evenari M. , Shanan L. , Tadmor N. H.
Published: July 2010

Soil moisture and trunk growth of young apricot and peach trees were measured under flood water spreading conditions in the desert. Rates of moisture depletion and trunk growth were different for each species and did not appear to be related to available soil moisture. Young apricot trees produced nearly three times the trunk cross sectional area as peach trees per unit of water depletion. Root distribution of the trees was estimated by interpreting the changes in soil moisture.
Germination Behavior of Salsola as Influenced by Temperature, Moisture, Depth of Planting, and Gamma Irradiation1
Authors: Wallace A. , Rhods W. A. , Frolich E. F.
Published: July 2010

Salsola kali, L. seeds contain fully differentiated seedlings and these uncoil in minutes with favorable temperature and moisture. If germinated on the soil surface, the uncoiled seedling will dehydrate and the if it cannot push its roots into the soil. Germination is most favorable for seeds covered with soil. For this reason the species generally appears only on disturbed soils. Seeds germinate satisfactorily at 17 C and at 9.1% soil moisture in Yolo loam stabilized with krilium and seedlings emerged from a planting depth of 7.5 cm. Evidence obtained with gamma irradiation from a Co60 source indicates that germination consists of rapid cell elongation in response to moisture and that new cell division is not necessary to the process. Irradiation of seed at levels above about 50,000 R impaired cell division but levels of over 400,000 R were necessary to cause additional germination injury.
Water Loss from a Sorghum Field and Stomatal Control1
Authors: Van Bavel C. H. M. , Ehrler W. L.
Published: July 2010

Measurements of temperature and diffusion resistance of leaves and of micrometeorological factors in a wellwatered sorghum field during June in central Arizona show that the stomata regulate transpiration only during the periods of darkness and low light. This was concluded from a comparison of the values for the canopy resistance as derived from direct measurement on leaves and as calculated from the environmental data.

This finding predicts that, during the main part of the daylight period, neither an increase in number or aperture of stomata nor a wetting of the entire foliage would increase the evaporative flux. The action of the sorghum plant is then like that of a wick.

We also found that, in a hot and dry environment, the sorghum foliage will constantly be several degrees cooler than the ambient air, even in the middle of the day when radiant energy input is large. Finally, the energy equivalent of the evaporative flux exceeded the net radiant flux significantly at all times, and by 80% over a 24‐hour period.

All three findings are at variance with common generalizations concerning the energetics and mechanics of crop transpiration. However, we recognize that our findings cannot be generalized to include other crop plants without specific studies.
Effect of Environmental Conditions on the Growth of Four Perennial Grasses. I. Response to Controlled Temperature1
Authors: Baker Barton S. , Jung G. A.
Published: July 2010

The growth of timothy (Phleum pratense L.), bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), and Kentucky bluegrass (Poa pratensis, L.) was studied under controlled temperatures varying by 3.3 C intervals from 18.3 to 34.8 C during the day and from 1.8 to 18.3 C during the night. A day temperature between 18.3 and 21.6 C was optimum for top growth with timothy, orchardgrass, and bluegrass. With bromegrass, the optimum day temperature was between 18.3 and 24.9 C. As the day temperature was increased from these optimum ranges to 34.8 C, all of the species decreased in yield, but the decrease in bromegrass yields was less than in any of the other species. In some cases, night temperature also affected yields; but the optimum night temperature depended upon the species and the day temperature.

The dry weight of etiolated growth indicated that the level of food reserves varied greatly. The species ranked orchardgrass > bromegrass > bluegrass > timothy for level of reserves. The most important factor affecting the level of reserves in a particular species was night temperature. In general, the food reserves decreased as the night temperature was increased from 1.8 to 18.3 C.
Effect of Cropping Intensity on Erosion and Infiltration1
Authors: Mannering J. V. , Meyer L. D. , Johnson C. B.
Published: July 2010

Soil loss and infiltration from corn (Zea mays L.), for rotations ranging in intensity from corn after 3 years of meadow to continuous corn, were measured on a silt loam soil of 5% slope. Intense simulated rainstorms were applied at three crop stages during each of 2 successive years. Infiltration rates for first‐ and second‐year corn after grass‐legume meadow were 32 and 26% greater, respectively, than for continuous corn. The rate for third‐ and fourth‐year corn was similar to that of continuous corn. Soil losses from first‐, second‐, third‐, and fourth‐year corn after meadow were 53, 83, 90, and 97%, respectively, of that from continuous corn. Two or 3 years of meadow were more effective than 1 year of meadow in maintaining high infiltration rates and reducing soil loss on first‐year corn. Infiltration was 17% and 18% greater and soil losses were 40% and 32% less for corn ulster 2 and 3 years of meadow, respectively, than after 1 year of meadow. Residual influences of meadow‐based rotations on water‐stable aggregation statistically accounted for greater than 70% of the variance in soil loss.
Pod Breakdown, Yield, and Grade of Virginia Type Peanuts as Affected by Ca, Mg, and K Sulfates1
Authors: Hallock D. L. , Garren Kenneth H.
Published: July 2010

Above‐normal rates of gypsum (CaSO4‐2H2O), up to 3,090 kg/ha broadcast in early bloom stage, on peanut (Arachis hypogea L.) plants of the ‘Virginia bunch 46‐2’ cultivar reduced pod breakdown, a destructive preharvest disease, in 2 out of 3 years, 1964–66. Gypsum increased fruit yields and percent sound mature seeds and decreased percent extra large seeds and percent fancy size pods in 1964 and 1965. In all 3 years, gypsum increased percent Ca in pods, and decreased percent K in pods and percent externally damaged seeds.

In 1965, 1,345 kg/ha MgSO4 broadcast on plants in early bloom stage increased pod breakdown and percent externally damaged seeds and decreased percent Ca in pods.

K2SO4 at 1,510 kg/ha in 1965, and 1,010 and 2,020 kg/ha in 1966, increased pod breakdown, percent K in pods, and percent externally damaged seeds. K2SO4 also decreased fruit yield and percentages of extra large and sound mature seeds, fancy size pods, and Ca in pods.
Effect of Age at Harvest on Yield and Cell Wall Content of Amclo Clover1
Authors: Stanley R. L. , Beaty E. R. , Palmer D. N.
Published: July 2010

During the falls of 1965 and 1966 ‘Amclo’ clover (Trifolium vesiculosum) was allowed to volunteer, and starting the following spring in mid‐March new plots were clipped each week to establish the rate of dry matter and cell wall development accumulation. The clipping was continued until early June at which stage the clover had matured. Data obtained indicated that Amclo was capable of producing more than 100 kg/ha of dry forage each day at the peak of productivity. In dry years, however, a much lower level of productivity can be expected. In the young vegetative forage, cell walls comprised less than 40% of the total yield. During flowering, cell walls increased to 40 to 47% of the total yield. At maturity cell walls increased to more than 50% of the total. Both yield and cell walls varied significantly between years.
Effect of Height of Cut on Yield of Pensacola Bahiagrass1
Authors: Beaty E. R. , Stanley Robert L. , Powell John
Published: July 2010

A clipping study on Pensacola bahiagrass (Paspalumnotatum var. ‘saurae Parodi’) over a 2‐year period, 1965 and 1966, showed that approximately 40% of the forage produced was within 2.54 cm of the soil surface. An additional 16 to 18% of the forage was produced between 2.54 and 5.08 cm from the surface. Only 9 to 16% of the forage was produced above 12.7 cm. N application tended to increase slightly the amount of forage produced above 12.7 cm and decrease the percent produced below 5.08 cm.

Conventional clipping at a height at 6.25 cm recovered 22 to 44% of the forage on the area and appears to be an unsatisfactory method for evaluating bahiagrass forage production. Clipping removed a lower percent of the forage present at the June and October harvests than at the July, August, or September clippings.
Compatability of Tall Fescue and Coastal Bermudagrass as Affected by Nitrogen Fertilization and Height of Clip1
Authors: Wilkinson S. R. , Welch L. F. , Hillsman G. A. , Jackson W. A.
Published: July 2010

Tall fescue (Festuca arundinacae) was seeded into dormant Coastal bermudagrass (Cynodon dactylon L.), fertilized at five levels of N, and clipped at 5.1 and 10.2 cm over a 3‐year period to evaluate the influence of these factors on its persistence in competition with Coastal. The experiment was conducted at two adjacent locations, with one irrigated and the other not irrigated.

Tall fescue persisted and contributed to yield at N levels up to 420 kg N/ha per year at the 5.1‐cm clip height, and at N levels up to 560 kg N/ha per year at 10.2‐cm clip height. Nitrogen fertilization decreased fescue content, whereas, the higher clipping increased fescue content of the harvested forage. Fescue content was high in the spring and fall and low in summer. Fescue growth during summer was better at the irrigated location. High N fertilization gave the highest yields, with little fescue in the harvested forage. Tall fescue‐Coastal associations have potential in grazing systems for cow‐calf operations where even seasonal distribution of forage may be important.
Water Potential Measurements of an Intact Plant‐Soil System1
Authors: Hoffman Glenn J. , Splinter William E.
Published: July 2010

Thermocouple psychrometers were used to measure the water potential of an intact plant‐soil system. The system consisted of a young tobacco plant grown in a container of fine sandy loam soil. The effects of soil water potential, diurnal fluctuations, and atmospheric relative humidity on the leaf water potential within a leaf and at different locations on the plant were studied.

Water potential was found to decrease from the base of the leaf to the tip. Leaves at the base of the plant were found to have lower water potentials than leaves near the middle. The soil water potential decreased linearly with time as evapotranspiration occurred in the system. The site of measurement on the leaf, atmospheric relative humidity, and diurnal variations were found to affect the relationship between leaf and soil water potential. At a constant relative humidity a linear relationship was obtained when the leaf water potential was measured at the base of the bottom leaves or at a given time each day to eliminate diurnal variations. In general, however, the relationship between leaf and soil water potential was not found to be linear. Soil water potential, atmospheric relative humidity, and diurnal variations were found to reduce the leaf water potential by at least 100% in tobacco if altered within the range found under field conditions.
Influence of 2,3,5‐triiodobenzoic acid (TIBA) On Soybeans Planted in Different Cultural Systems1
Authors: Wax L. M. , Pendleton J. W.
Published: July 2010

Field studies were conducted over a 2‐year period at Urbana, Ill., with two soybean varieties [Glycine max (L.) Merr.], to evaluate their response to 2,3,5‐triiodobenzoic acid (TIBA) in various cultural management systems.

Soybean yields increased as row spacing decreased from 101.6 to 25.4 cm. Compared to the yield from the 101.6 cm row spacing, the increase was 10, 18, and 20% for 76.2, 50.8, and 25.4 cm row spacings, respectively. The variety ‘Wayne’ outyielded ‘Harosoy 63’ at all row spacings and TIBA treatments. TIBA had little effect on yield at the 101.6, 76.2 and 25.4 cm row spacings, but caused a yield increase of about 6.5% with both varieties at the 50.8 cm row spacing.

For both varieties, TIBA treatment significantly reduced height and lodging at all row spacings, increased pod set, and decreased seed weight. Neither TIBA nor row spacing influenced oil or protein composition of the seed.
Comparison of Materials for Reducing Evaporation of Soil Moisture in Water Efficiency Studies1
Authors: Dobrenz A. K. , Cole D. F. , Joy R. J.
Published: July 2010

Coarse styrofoam was a non‐toxic, permeable, lightweight material which reduced evaporation from the soil surface by 78% compared with bare soil. This material is easy to apply and allows for uniform evaporation under controlled environmental conditions which have high temperatures and low humidity.
Net and Spectral Radiation in Soybean Canopies1
Authors: Singh Maharaj , Peters D. B. , Pendleton J. W.
Published: July 2010

Net and spectral radiation profiles were measured for two soybean varieties of different leaf shapes. Net radiation attenuation differences were found for varieties but not for row spacings. The attenuation coefficient for both spectral and net radiation was very high, indicating the principal use of radiation is in the outer periphery of the soybean canopy. Net radiation was found to deviate from a Beer's Law absorption in the lower region of the soybean canopy.
Growth and Forage Quality Comparisons of Sainfoin (Onobrychis viciaefolia Scop.) and Alfalfa (Medicago sativa L.)1
Authors: Carlton A. E. , Cooper C. S. , Delaney R. H. , Dubbs A. L. , Eslick R. F.
Published: July 2010

We calculated seasonal accumulation of dry matter and crude protein in sainfoin and alfalfa and feed quality at three stages of maturity when species were grown on irrigated and dryland. Maximum accumulation of dry matter and crude protein occurred between 2 and 45% bloom for alfalfa and at 100% bloom for sainfoin on irrigated land. Dry matter and crude protein yield trends for both crops were similar on irrigated land and dryland. The maximum dry matter and crude protein contents for both sainfoin and alfalfa occurred at about the same calendar date on dryland but at different dates under irrigation. Decreases in the percentage of crude protein were similar in both species with time. At all sampling dates crude protein percentage of alfalfa was greater than for sainfoin.

At similar stages of maturity alfalfa was consistently higher than sainfoin in crude protein, ash, calcium, and crude fiber; and with few exceptions it was lower in nitrogen‐free extract, total digestible nutrients, and P. At the point of maximum yield for each species (10% bloom for alfalfa, 100% bloom for sainfoin) crude fiber and total digestible nutrient content was similar, but alfalfa contained 6% more protein and 9 to 10% less nitrogen‐free extract than sainfoin. We concluded that sainfoin hay would supply adequate protein to meet the needs of beef animals, and that it would supply total available energy equal or superior to that of alfalfa.