bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses of Potato Plants to Fertilization and Soil Moisture Tension Under Induced Soil Compaction1
Authors: Timm Herman , Flocker W. J. 
Published: July 2010

AbstractPotato 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

AbstractThe 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

AbstractDuring 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

AbstractA 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

AbstractThe 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

AbstractLadino 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

AbstractResponses 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

AbstractThe 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

AbstractAn 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

AbstractThe 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

AbstactThe 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

AbstractAgronomic 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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractSome 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

abstractLarge 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

AbstractThe 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

AbstractA 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

AbstractMaximum 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.