bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Nitrogen Fertilizer on Yield, Nitrogen Content, and Yield Components of Safflower
Authors: Jones J. P. , Tucker T. C.
Published: July 2010

Nitrogen fertilization produced large increases in safflower seed yield when amply irrigated, a lesser effect with moderate irrigation, and none where irrigation was severly restricted.

Total nitrogen in above ground plant portions increased with N fertilization rate, doubling from first bloom to maturity at all N rates. Percentage recovery decreased as applied N rates increased.

Nitrogen fertilization increased safflower seed yield with more heads in the tertiary position and increased weight per head in the secondary and tertiary position. Increased head weight resulted from increased weight per seed in secondary head position and increased number of seeds per head in the tertiary position.
Establishment of Tall Fescue and White Clover: Effects of Seeding Method and Weather1
Authors: Hart Richard H. , Carlson G. E. , Retzer H. J.
Published: July 2010

We drilled and broadcast‐seeded tall fescue (Festuca arundinacea Schreb.) and white clover (Trifolium repens L.) on three soil types, on 29 dates in 1963 and 1964. Tall fescue yields of the spring after seeding were generally higher from drilled than from broadcast stands. Although drought in the spring of 1965 reduced yields from most of the 1964 seedings, fescue yields were mainly limited by soil moisture supply immediately after germination. If drought occurs in this critical period, the fescue should be reseeded, because future forage yields will be greatly reduced. However, irrigation during this period should greatly increase potential yields the following year. The amount of white clover in the stand was limited by moisture and competition with fescue; there was more clover in broadcast stands, where competition with fescue for light and moisture was less severe, and in stands planted in summer, when more light could penetrate the stand.
Field Investigations of the Relationships of Leaf Angle in Corn (Zea mays L.) to Grain Yield and Apparent Photosynthesis1
Authors: Pendleton J. W. , Smith G. E. , Winter S. R. , Johnston T. J.
Published: July 2010

Field investigations were conducted at Urbana, III., concerning the relationship of leaf angle and canopy shape to grain yield and apparent photosynthesis of Zea mays L. A backcross‐derived isogenic single cross hybrid (‘C103’ ✕ ‘Hy’) carrying the lg2 gene for erect leaf produced 40% more grain than its counterpart with normal (horizontal) type leaf, when compared in rows 51 cm wide at 59,304 plants/ha. Mechanical manipulation of the leaves of a widely grown commercial hybrid. ‘Pioneer 3306’ into a more upright nature resulted in grain yields above that produced by the same hybrid in its normal leaf orientation and canopy shape. Apparent photosynthesis measurements on individual corn leaves showed the relative efficiency of CO2 fixation/unit of incoming sunlight to steadily increase as the leaf angle decreased. The results strongly support corn breeding programs in the area of plant geometry and crop canopy.
Reduction of Strontium‐85 Uptake in Field Crops By Deep Plowing and Sodium Carbonate Application1
Authors: Menzel R. G. , Eck H. V. , James P. E. , Wilkins D. E.
Published: July 2010

Deep plowing reduced uptake of Sr85 by four irrigated crops on Pullman silty clay loam at Bushland, Texas. Uptake was further reduced when Na2CO3 was plowed under with the Sr85. The relative concentrations of Sr85 in mature soybean (Glycine max), sugar beet (Beta vulgaris), sudangrass (Sorghum sudanense), and cabbage (Brassica oleracea var capitata) plants grown with Sr85 applied in different treatments were: rotary tilled 20 cm deep, 100; plowed 90 cm deep, 25–50; plowed 90 cm deep with 22,400 kg/ha (10 tons/acre) of Na2CO3, 3–7. In the plowing treatments, 90% of both the Sr>85 and the Na2CO3 were banded in the furrow deeper than 75 cm. Crop yields were increased by deep plowing and were affected very little by the application of Na2CO3. This experiment demonstrates that a toxic chemical can be plowed under deeply with radioactive contamination to reduce the uptake of the radioactive material with little effect on yield from the chemical.
Desiccation and Defoliation of Plants by Different Herbicides and Mixtures1
Authors: Bovey R. W. , Miller F. R.
Published: July 2010

Guava, hibiscus, sorghum, and cotton leaves were treated with 5 herbicides each at 10 dosages. Pentachlorophenol (PCP) and cis−2,3,5,5,5−pentachloro−4−ketopentenoic acid (AP−20) produced the most rapid desiccation at high dosages. The 6,7−dihydrodipyrido(l,2−α:2',I'−c)pyrazidünium salt (diquat) was usually as effective as PCP and AP−20 within 1 to 2 days after treatment, and it produced more extensive desiccation at lower dosages, especially on hibiscus, sorghum, and cotton. Diquat, l,l'−dimethyl− 4,4'−bipyridinium salt (paraquat), dimethylarsinic acid (cacodylic acid), and AP−20 produced complete defoliation of hibiscus within 5 days after treatment but diquat and paraquat were more effective at lower dosages than other defoliants. Diquat completely defoliated hibiscus at 19 µg regardless of placement on the leaf, but higher dosages were required for effective desiccation when applied non−uniformly over the leaf. Effective desiccation with PCP required uniform application to either upper or lower surfaces. Defoliation of leaves after treatment with PCP did not occur. Some herbicides increased the desiccation and defoliation of hibiscus synergistically when added to diquat. Hormone−type herbicides such as 2,4−dichlorophenoxyacetic acid (2,4−D) and 4−amino−3,5, 6−trichloropicolinic acid (picloram) were antagonistic to diquat.
Practical Suggestions on Pooling Variances for F Tests of Treatment Effects1
Authors: Carmer S. G. , Walker W. M. , Seif R. D.
Published: July 2010

A two‐part rule is given as a practical guide in preliminary tests of significance for determining whether or not to pool two or more variances for use as “error term” in subsequent F tests for treatment effects. Four examples involving commonly occuring analysis of variance tables are given to illustrate the use of the rule.
Root Growth Pressures of Cotton, Peas, and Peanuts1
Authors: Taylor Howard M. , Ratliff Larry F.
Published: July 2010

The root growth force that cotton (Gossypium hirsutum L. ‘Coker 413–68’), pea (Pisum sativum L. ‘Brunswick’), and peanut (Arachis hypogaea L. ‘Virginia Bunch’) seedlings developed was measured with an unbonded strain gage force transducer. Root growth pressure, defined as root growth force per unit root cross‐sectional area, averaged 9.4, 13.0, and 11.5 bars for cotton, peas, and peanuts, respectively, but values varied widely within each variety. Osmotic potential and root growth pressure results supported Pfetter's contention that cellular osmotic potential created the stress necessary for root growth pressure development.
Effects of Soil Temperature and Zinc Application on Yields and Micronutrient Content of Four Crop Species Grown Together in a Glasshouse1
Authors: Wallace A. , Romney E. M. , Hale V. Q. , Hoover R. M.
Published: July 2010

Four species of plants were grown together in Dinubasandy loam in pots which were placed in temperature controlled tanks to give root temperatures of 14, 20, and 26C. Sugar beets had been previously grown and the residues incorporated in the soil to help induce a low zinc status. Zinc labeled with Zn65 had been added to half of the pots. Vegetative yields of two crops, Zn65 contents, and micronutrient and phosphorus contents of the plants were tabulated. Yields generally increased wih soil temperature with or without zinc application. Cotton yields responded to zinc at the low soil temperature, bush bean yields at the high soil temperature, and corn responded at all three temperatures used. Zinc content tended to increase with soil temperature; the increase was significant in cotton without added zinc and in soybean either with or without added zinc. The zinc application generally resulted in a higher zinc content of plants; the two cases when this was not significantly so were at the high soil temperature. Zinc content and evidently zinc needs varied considerably. The specific activity of the zinc in the four species was remarkably uniform, but for three of them there was a tendency for a decrease at the highest soil temperature. Plant phosphorus tended to increase with soil temperature, and there was a slight interaction with zinc contents. There was some tendency for copper and manganese in plants to increase with zinc; iron did also but to a much lesser extent. Copper tended to increase with soil temperature but manganese tended to decrease at the high temperature. Boron varied for species only and aluminum decreased with increasing temperature.
Row Spacing and Fertilization Influences on Forage and Seed Yields of Intermediate Wheatgrass, Russian Wildrye, and Green Needlegrass on Dryland1
Authors: Black A. L. , Reitz L. L.
Published: July 2010

The effects of contour row spacings of 76, 107, and 152 cm and N and N‐P fertilization on forage and seed production of intermediate wheatgrass (Agropyron intermedium [Host] Beauv.), Russian wildrye (Elymus junceus Fisch.), and green needlegrass (Stipa viridula Trin.) were evaluated over a 5‐year period.

With 45 or 67 kg/ha of N applied annually, forage and seed yields of all species increased 1.5‐ to 2.0‐fold regardless of row spacing, independent of added P. The need for N and N‐P fertilization increased with age of stand regardless of row spacing. Without N or N‐P fertilization, row spacings had no significant influence on forage or seed production of intermediate wheatgrass or Russian wildrye. Forage and seed yields of green needlegrass decreased progressively as row spacing increased regardless of N or N‐P fertilization.

Nitrogen recoveries by the three grasses ranged from about 20 to over 50%. In general, N fertilizer recovery was highest from plots with the highest yields and greatest water‐use efficiencies. Russian wildrye grown in 76‐ or 107‐cm rows recovered more than 50% of the N fertilizer applied.

Considering all factors involved—forage and seed yields, water‐use efficiencies, and plant N and P uptake—intermediate wheatgrass, Russian wildrye, and green needlegrass should be grown in 107‐ 76‐, and 76‐cm row spacings, respectively, with annual applications of 40 to 60 kg/ha of N with P added.
Seasonal Patterns in Evapotranspiration by Irrigated Alfalfa in the Central Great Plains1
Authors: Rosenberg Norman J.
Published: July 2010

Evapotranspiration (ET) by irrigated alfalfa in eastern Nebraska, as determined with precision weighing lysimeters during 1967, varied qualitatively and quantitatively with season. ET in early spring may exceed the net radiation. Low temperature, however, induces a strong canopy resistance and ET can then be significantly lower than atmospheric conditions suggest possible, Maximum ET measured during this season was approx. 6.5 mm day−1.

Strong local and/or regional advection may prevail in late spring and ET rates may be as high as 12 mm day‐1. ET may exceed Rn by 80% during this season which is often characterized by very low humidity when winds stem from SW through N.

Mid‐summer is characterized by hot and humid conditions under predominantly S and SE winds. ET exceeds Rn only little during this season. Maximum ET rate is about 7.5 mm day‐1.

Nocturnal ET is common during the alfalfa growing season. Strong temperature inversions account for a downward delivery of sensible heat sufficient to explain this effect. As much as 1 mm per night can be transpired by alfalfa.

The Energy Balance Bowen ratio method estimated hourly ET more closely than did an aerodynamic method uncorrected for atmospheric stability conditions. Neither method gave estimates more reliable than ±0.151y rain‐1.

The Penman method underestimates ET under potential evaporation conditions by as much as 30%, particularly when advection is strong. The van Bavel method for estimating potential evaporation is very sensitive to the value assigned the roughness parameter. With Z0 = 2 cm this method estimates potential evaporation of 8 to 28% more than with Z0 = 1 cm. The van Bavel method is also sensitive to windiness, underestimating ET on calm days and overestimating on windy days.
Some Effects of Soil Moisture Stress on the Growth of Wheat (Triticum aestivum L. em Thell.)1
Authors: Day A. D. , Intalap Suhbawatr
Published: July 2010

Investigations were conducted in 1966 and 1967 at Tucson, Ariz., to study some effects of soil‐moisture stress, at three different stages of development (jointing, flowering, and dough) on the growth and grain yield of spring wheat (Triticum aestivum L. em Thell.) planted in December. A critical period in the growth of wheat was the jointing stage for moisture. Stressing wheat for water at jointing resulted in fewer days from planting to flowering, shorter plants, more lodging, lower grain yield, lower grain volume‐weight, fewer heads per unit area, and fewer seeds per head. Soil‐moisture stress at any stage of growth decreased grain yield. When wheat was stressed at jointing, reduced grain yield resulted from fewer heads per unit area and fewer seeds per head. However, when moisture stress occurred at the flowering and dough stages, lower grain yields were caused by lighter seed‐weight. Stress at the flowering and dough stages also hastened maturity.
Meso‐Scale Effects of Agriculture and a Large Prairie Lake on the Atmospheric Boundary Layer
Authors: Holmes R. M.
Published: July 2010

Thermal gradients were measured in the atmospheric boundary layer over an extensive agricultural region using an instrumented aircraft and a mobile ground station mounted on an automobile. It was noted that sharp changes in the temperature of the surface produce similar temperature changes in the atmosphere above. Near the surface the temperature discontinuities in the atmosphere were located almost immediately above the heat sources or sinks. But higher in the atmosphere, the cooled or heated air persisted for appreciable distances down wind. A large lake and an irrigated region produced 3.0 C and 2.0 C cooling, respectively at 20‐m elevation, and virgin prairie caused a temperature increase of 2.0 C in the atmosphere at 20 m. The temperature changes indicated are statistically significant compared to the temperature of prairie air 8 km up wind at the same elevation.
Yield Response of Upland Cotton (Gossypium hirsutum L.) to Several Spacing Arrangements1
Authors: Hawkins B. S. , Peacock H. A.
Published: July 2010

A 3‐year study with Upland cotton (Gossypium hirsutum L.) was conducted at Experiment, Ga., to determine the effects of plants/hill, within‐row hill spacings, and plant populations on lint yield.

Highest yields were obtained when the populations were within a range of 96,000 to 144,000 plants/ha. Below this population range yield decreased sharply; above this population range yield was reduced but the rate of decline was more gradual than the decline in the low population range. The highest average yield (919 kg lint/ha) was obtained from five plants/hill spaced 40 cm apart (120,412 plants/ha). When all hill spacings were combined, the mean yield from five plants/hill (879 kg/ha) was significantly (P = .05) higher than yield from two plants/hill (812 kg/ha). Yield differences among hill populations of three, four, or five plants were not significant. When the plants/hill treatments were combined, yields from plants spaced 20 and 40 cm apart were significantly higher (P = .01) than yield from plants spaced 60 cm apart. The plants/hill ✕ hill spacings interaction was not significant.
Effects of Plant Population and Harvest Date on Stem Yield and Growth Components of Kenaf in Maryland1
Authors: Higgins J. J. , White G. A.
Published: July 2010

Kenaf is a potential new annual crop source of paper pulp. To minimize storage stockpiling of this new, bulky raw material, pulp processors may begin harvesting well before killing frosts and continue for several months beyond. Possible stem yield reductions with this extended harvesting system and the influence of plant populations on the reductions becomes of practical concern. The effects of four populations and five harvest dates on stem yields and other growth components on kenaf variety ‘Everglades 71’ were studied at Glenn Dale, Md., in 1966 and 1967. Populations of 99, 198, 297, and 395 thousand plants/ha did not affect stem yield or plant height in 1966 or yield in 1967. Basal stem diameters decreased as populations increased. There was a gradual loss of plants as harvesting was delayed. The greatest loss of about 25% was for the highest population. The best stem yields across the four populations were obtained from Oct. 4, 1966, (13.5 mt/ha) and Nov. 7, 1967, (11.7 mt/ha) harvests. These data indicate that populations of 200 to 300 thousand plants/ha and harvesting at about the time of killing frosts will result in the highest stem yields of kenaf under Maryland conditions.
Factors Influencing Freezing of Supercooled Water in Tender Plants1
Authors: Cary J. W. , Mayland H. F.
Published: July 2010

Seedlings of beans (Phaseolus vulgaris), corn (Zea mays), and tomatoes (Lycopersicon esculentum) were grown in the greenhouse and then exposed to controlled freezing conditions in a growth chamber. Variables were adjusted to determine the influence of plant water potential, freezing time, and external dew formation on the seedlings' susceptibility to frost injury. Freezing, detected visually and by release of latent heat, progressed rapidly throughout plants with high water potential and was always lethal. Spreading of the ice phase was impeded in plants with low water potential. In this case, the freezing injury appeared as spots on the leaves which gradually enlarged to encompass the entire leaf as the exposure continued. In general, the plant water supercooled before freezing. Supercooled water within the plant appeared to be internally nucleated if the leaf temperature remained above th atmospheric dewpoint temperature. Under these conditions root temperature, plant water energy, and duration of the freezing period all influenced the stability of the supercooled water. On the other hand, external inoculation prevailed when the freezing temperatures were accompanied by condensation of water from the air and subsequent formation of ice crystals on the leaves. One important exception was noted when ice on corn seedling leaves failed to nucleate the supercooled internal plant water with a potential of −18 bars.
Perennial Irrigated Pastures. I. Plant, Soil Water, and Animal Responses Under Rotational and Continuous Grazing1
Authors: Raguse C. A. , Henderson D. W. , Hull J. L.
Published: July 2010

Continuous grazing favored strawberry clover (Trifolium fragiferum L. ‘Salina’), and rotational grazing (5‐field; 1‐week grazing, 4‐week recovery) favored Ladino clover (T. repens L.) in a sward containing Ladino clover, ‘Salina’ strawberry clover, orchardgrass (Dactylis glomerata L), and perennial ryegrass (Lolium perenne L.). A 2‐field rotation (I‐week, I‐week) favored strawberry clover but had less influence on botanical composition than either 5‐field rotation or continuous grazing. Continuous grazing resulted in a higher percentage of plant cover than did 5‐field rotational grazing. Yields of beef per unit area were similar under the three systems. Water infiltration increased progressively during the 4 years of the experiment, and final infiltration rates were 2 to 3 cm/hr in both continuous and rotationally grazed pastures.
Co‐Grazing of Sheep and Cattle on an Orchardgrass Sward
Authors: Reynolds Paul J. , Bond James , Carlson G. E. , Jackson Charlie , Hart R. H. , Lindahl Ivan L.
Published: July 2010

The objective was to determine whether there is any advantage to co‐grazing, i.e., the grazing of cattle and sheep together, relative to grazing either species separately. The study was conducted over four successive grazing seasons on a highly fertilized sward that was a mixture of Ladino clover (Trifolium repens L.) and orchardgrass (Dactylis glomerata L.) the first season and nearly pure orchardgrass thereafter.

Two apparent effects of co‐grazing were observed: First, an increase in rate of gain of sheep grazed with cattle at a ratio of five sheep per steer. This greater rate of gain, however, did not result in a greater liveweight gain/ha of cattle and sheep combined. Available forage was maintained at fixed levels, and the lack of any advantage in total gain/ha to co‐grazing at a ratio of 1 steer per 5 sheep is discussed in relation to similar experiments in which an advantage to co‐grazing was observed, but in which the effects of cattle:sheep ratio and available forage were confounded.

Second, at one sheep per steed the animals were cograzed without affecting the rate of gain of the steers, but with an apparent increase in liveweight gain/ha relative to either cattle or to sheep grazed separately. This apparent effect of co‐grazing, however, was probably the result of a subtle increase in stocking rate that could have been brought about by either species independently of the other and, therefore, is not attributable to cograzing per se.
Corn Performance in Relation to Row Spacings, Populations, and Hybrids on Five Soils in Indiana1
Authors: Stivers R. K. , Griffith D. R. , Christmas E. P.
Published: July 2010

The purpose of this research was to determine whether narrow rows of corn (Zea mays L.) would yield more grain and dry matter than conventional 102−cm wide rows under a wide range of conditions. Eleven location‐year trials were conducted on five slightly acid soils at four widely scattetred locations in Indiana during 1966–1968. Three row widths: 51−, 76−, and 102−cm; two populations: 54,000 and 69,000 plants/ha; and three hybrids: one early, one full season, and one full season or late; were compared. Average grain yields were increased 7.3% with rows 51−cm wide, and 4.4% with rows 76−cm wide in comparison to rows 102−cm wide. More barren stalks contributed to the lower yields of the 102−cm rows under drouth stress conditions.

Total aboveground dry matter yields on Chalmers silty clay loam soil were 5.0% higher with 51−cm rows and .5.4% higher with 76−cm rows than those of the 102−cm rows. The 69,000 plants/ha population produced 4.0% more dry matter than the 54,000 population on this Chalmers soil.

Average grain yields of the 69.000 plants/ha population were 2.3% lower than those of the 54,000 population in the II location‐year trials.

Full season corn hybrids generally produced higher yields of grain than either early or late hybrids in these trials. Some full and late, as well as early season, corn hybrids had higher grain yields with narrow corn rows.
Nutritive Relationships in Low‐ and High‐tannin Sericea Lespedeza Under Grazing1
Authors: Donnelly E. D. , Anthony W. B. , Langford J. W.
Published: July 2010

A study was made on low‐ and high‐tannin sericea lespedeza [Lespedeza cuneata (Dumont) G. Don] to obtain information, using grazing steers, on the relationship of tannin and digestible dry matter (DDM), digestibility of crude protein, daily dry‐matter intake, and daily DDM intake. Tannin, crude protein, DDM, digestibility of crude protein, daily dry‐matter intake, daily DDM intake, and fecal crude protein were determined. Crude protein percentage was the same for the two forages and remained relatively high throughout three grazing periods from May through mid‐September. However, crude protein and dry matter of low‐tannin sericea were more highly digested than that in high‐tannin sericea.
Retention Patterns and Effectiveness of Anhydrous Ammonia Applied with an Undercutting Blade1
Authors: Swart C. L. , Murphy L. S. , Swallow C. W.
Published: July 2010

Retention of and distribution patterns of anhydrous ammonia applied with an undercutting blade were investigated on soils of varying cation exchange capacities (CEC). Rates of ammonia ranged from 56 to 224 kg N/ ha; spacings between points of ammonia release ranged from 15 to 102 cm. Application depths were 5 and 10 cm.

Applying 224 kg N/ha on a silt loam soil resulted in no measurable loss at any depth or spacing. Shallow (5‐cm) applications resulted in some ammonia loss on a low CEC soil; 224 kg N/ha applied 10 cm deep also resulted in ammonia loss when dispersed with 102‐cm spacings. A 15‐cm spacing, however, reduced the loss to less than 1%. Soil texture and depth of application did not appreciably alter the distribution patterns but affected ammonia losses.

Distinct distribution patterns resulted from each release‐point spacing. Ammonia distribution patterns were commonly oval around each release point. Lateral movement was directly proportional to application rate, while vertical movement was limited to less than 5 cm.

A second phase of the study involved preplant field applications of ammonia for wheat (Triticum aestivum L.). Effects of N rate and spacing of release points on plant N absorption, wheat yield, test weight, and protein content of the grain were recorded for five Kansas locations.

Plant N concentration correlated positively with soil inorganic N in samples collected 7 months after NH3 application. Variations in NH3 release‐point spacings produced marked differences in growth, particularly in the spring. The 15‐cm and 41‐cm release‐point spacings generally produced more uniform plant growth, which resulted in higher yields than the 102‐cm spacing; however, the differences were not significant at the 5% level.
Effect of Different Levels of Nitrogen and Phosphorus on Yield, Soil Properties, and Nutrients of Corn1
Authors: Shukla G. C.
Published: July 2010

The effect of five levels of N and three levels of P on yields, soil properties, and uptake of nutrients of corn (Zea mays L.) was studied at Central Agricultural Station (CAS), Central Horticultural Station (CHS), and Black Bush Polder (BBP) in Guyana. Corn yield showed a significant response up to 180 kg N/ha applied at CAS and CHS. At BBP the yield increase was nonsignificant. P gave a significant effect on yield in one season at CAS only.

The changes in soil properties from the time of planting first crop to the harvesting of the second crop at CAS and CHS are described. Application of N had a residual effect on both the soils. The changes in P and K followed different patterns on two soils. After cropping, pH and exchangeable Ca and Mg increased in both the soils.

Nitrogen rates significantly increased N and K and decreased P content of the leaves. P levels had a nonsignificant effect on the uptake of nutrients.
Effects of Trifluralin on Fertilizer Phosphorus Uptake Patterns by Cotton and Soybean Seedlings1
Authors: Cathey George W. , Sabbe Wayne E.
Published: July 2010

Two greenhouse experiments were conducted to study the effect of trifluralin (a, a, a, trifluoro ‐ 2, 6‐dinitro‐N, N‐dipropyl ‐ p‐ toluidine) on P uptake patterns by cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] seedlings. Fertilizer P uptake from each of three soil zones was altered when the herbicide was present in the root substrate. The greatest alteration occurred when the herbicide was located in the center soil zone (5 to 10 cm). The uptake of P was decreased when the fertilizer and trifluralin were located in the same soil zone, whereas, in some cases a stimulation of P uptake from the fertilizer zone occurred when the herbicide was confined to a separate soil zone. The fertilizer P uptake was affected least when the herbicide was placed in the top soil zone (0 to 5 cm).
Prediction of Flowering Dates in Maize Based on Different Methods of Estimating Thermal Units1
Authors: Cross H. Z. , Zuber M. S.
Published: July 2010

In an attempt to find better ways of estimating relative maturity differences in corn (Zea mays L.), various thermal unit formulas were evaluated. Utilizing data from six plantings of corn over a 2 year period, 22 different methods of computing thermal units were tested for their ability to account for variation in flowering dates. Both hourly and daily temperature data were used in the equations. In general the daily measurements appeared to be approximately as accurate as the hourly measurements. The best equation for predicting flowering dates on the basis of thermal units utilized a base temperature of 10C (50F) and an optimum of 30C (86F). The excess temperature above 30C was subtracted to account for high temperature stress.
Emergence Force of Forage Seedlings1
Authors: Jensen E. H. , Frelich James R. , Gifford R. O.
Published: July 2010

The experiments were conducted to quantitatively determine the relative force exerted by germinating forage seedlings. Information obtained could be used for the selection of forage species most likely to emerge through soil crusts.

An apparatus was used that employed a force transducer to measure the relative force exerted during seedling emergence. A continuous record of the vertical force was observed for each seedling. The resulting curve reflected the relative force a seedling exerted at a particular time of emergence after germination.

The emergence force exerted by a seedling differed significantly among alfalfa (‘Medicago sativa’ L.), strawberry clover (Trifolium fragiferum L. ‘Salina’), alsike clover (Trifolium hybridium L.), and narrow‐leaf birdsfoot trefoil (Lotus tennis Wald. et. Kit.) and was positively correlated with seed weight. Alfalfa exhibited a significantly higher mean weekly emergence force, while narrowleaf birdsfoot trefoil seedlings exerted a significantly lower mean weekly emergence force than the other species tested. Curves generally indicate that force increased very rapidly for legumes 24 to 48 hours after transplanting with a gradual decrease thereafter. The magnitude of force exerted by tall wheatgrass (Agropyron elongatum Host) and alfalfa seedlings was not significantly decreased until —5.0 bars of osmotic potential (O.P.) was imposed. A decrease in O.P., however, significantly increased the time required to reach a maximum force by alfalfa but not by tall wheatgrass. Force curves of tall wheatgrass indicated that 5 to 6 days were required to reach a maximum force, compared to 1 to 2 days for legumes. Sodium adsorption ratios did not affect the emergence force of alfalfa seedlings.
Effect of Temperatures and Water Table Depth on the Growth of Creeping Bentgrass Roots1
Authors: Ralston D. S. , Daniel W. H.
Published: July 2010

The PURR‐WICK system, as developed at Purdue University in 1966, provides an impermeable underlay, plus possible retention of free water by outflow drainage control. What would be the effect in this system of sand texture, depth of water reserve, and temperature? ‘Penncross’ bentgrass (Agrostis palustris Huds.) was grown in columns of finer and coarser sand mixes with water tables maintained at depths of 11, 25, and 40 cm in constant temperature chambers of 15 and 30 C for 9 weeks.

Temperature had the greatest effect. At 15 C root growth was slow initially but steadily maintained. At 30 C initial root growth was rapid but declined to little or no growth, so that total root length at 15 C was three times that for 30 C. Within each temperature the water table ✕ sand interaction was significant. Root growth was better in the coarser sand for the 11‐ and 25‐cm water tables and better in the finer sand for the 40‐cm treatment. The deepest root growth was found at 15 C in the finer sand mix with the water table at 40 cm. Where oxygen diffusion was favored by coarse texture, roots were still limited by higher temperature.
Selenium Accumulation in Astragalus Species
Authors: Davis A. M.
Published: July 2010

Some Astragalus species are known to be Se accumulators and are toxic to grazing animals. The Western Regional Plant Introduction Station, Pullman, Wash., had 108 accessions representing 49 species of Astragalus, mostly of non‐North American origin, available for this study. The Se accumulation characteristics of these had not been determined and therefore their potential as forage in areas of seleniferous soil was open to question.

Plants were greenhouse grown in soil containing 18 ppm Se. The forage was dried and analyzed for total Se by AOAC methods.

Selenium content varied from a high of 213 ppm in Astragalus tephrosoides Boiss. to a low of no detectable Se in 45 accessions. Sixty accessions, representing 26 species, accumulated 5 ppm Se or more and could be poisonous to grazing animals.
Bird Resistance in Diverse Germplasm of Sorghum1
Authors: McMillian W. W. , Wiseman B. R. , Burns R. E. , Harris H. B. , Greene G. L.
Published: July 2010

This study was conducted to examine the relative amount of bird resistance present in a broad spectrum of available sorghum [Sorghum bicolor (L.) Moench] since bird resistance is highly desirable for inclusion into plant breeding programs. Ratings were taken on damage inflicted by natural populations of birds and on several plant characters, including tannin content of the seed, color of the seed, and plant height. The bird damage done to 142 domestic and exotic lines of sorghum revealed the presence of germplasm imparting resistance to birds: SPI 35038 had a low damage rating (2.5); lines SA 370 and Colby had a high damage rating (9.0). Some commercially available sorghum hybrids also appeared to have resistance. The amount of tannin in the sorghum seed was negatively associated with bird damage, as were seed color and plant height, although to a lesser extent. The amount of tannin and seed color showed a positive correlation. Nevertheless, several sorghum lines appeared to be resistant that contained a relatively low amount of tannin.
Effect of N Fertilization on Dry Matter Yield, Total‐N, N Recovery, and Nitrate‐N Concentration of Three Cool‐Season Forage Grass Species1
Authors: George J. R. , Rhykerd C. L. , Noller C. H. , Dillon J. E. , Burns J. C.
Published: July 2010

This study was undertaken because of continued interest in replacement of legume N with commercial N for perennial grasses. More information is needed on the time and level of applied N to maximize total yield, seasonal distribution of forage, and efficient use of N fertilizer, while minimizing nitrate‐N accumulations in the forage. Timothy (Phleum pratense L.), smooth bromegrass (Bromus inermis Leyss.), and orchardgrass (Dactylis glomerata L.) were evaluated during the 1st (1964) and 2nd (1965) years after seeding. Nitrogen levels employed were O, 21, 42, 84, 168, and 336 kg/ha applied each harvest, providing maximum annual rates of 1,008 kg/ha for timothy and 1,344 kg/ha each for bromegrass and orchardgrass.

Highest dry matter yields were obtained with orchardgrass, followed by bromegrass and then timothy. Yields were limited by drought in 1964, with timothy the most sensitive. Dry matter yields of orchardgrass and bromegrass exceeded 11,000 kg/ha in 1965, whereas timothy produced a maximum of 6,770 kg/ha. Production of orchardgrass was generally superior in midsummer. A low priority is suggested for timothy in the central and southern Corn Belt region due to its poor drought tolerance and low yield. Higher rates of N depressed forage yields, especially in 1965 due to a reduction in stand, with timothy affected most.

Total‐N concentrations were similar in bromegrass and orchardgrass and generally lower in timothy. Recovery of applied N in the harvested forage was highest when 2 kg/ha of N was topdressed per harvest. Nitrogen recoveries were higher in 1965 with maximums of 48.5, 71.8, and 66.6% for timothy, bromegrass, and orchardgrass, respectively. These data suggest that established sod‐forming species may utilize applied N more efficiently than bunchgrasses, with timothy being quite inefficient presumably due to limited root volume and poor drought tolerance.

Potentially toxic concentrations of nitrate‐N (.15%) were not found when N rates did not exceed levels required to maximize forage yield. The major exception occurred for July harvests of bromegrass and orchardgrass in 1965. These data suggest that bromegrass should be added to the list of species that could accumulate “unsafe” levels of nitrate‐N under certain conditions of N fertilization.
Leaf Blade Areas of Grain Sorghum Varieties and Hybrids1
Authors: Liang G. H. , Chu C. C. , Reddi N. S. , Lin S. S. , Dayton A. D.
Published: July 2010

The experiments were conducted to evaluate the amount of heterosis for leaf‐blade area in grain sorghum {Sorghum bicolor (L.) Moench} hybrids. Total leaf‐blade area was measured on plants of six varieties and their 15 hybrids, at two locations in 1971. Hybrids had significantly greater total leaf‐blade area, average leaf‐blade area, average leaf length and width, and grain yield as compared to parents. However, parents had significantly more leaves than hybrids. Differences between parents and hybrids for total leaf‐blade area, average leaf‐blade area, and average leaf‐blade width varied from location to location. Blade areas of leaves 2, 4, 5, 6, and 7 (flag leaf as number 1) of the hybrids were significantly larger than those of corresponding leaves of the parents. Total leaf‐blade area correlated positively and significantly with leaf‐blade area of the largest leaves, numbers 5, 6, 7 and 8. Adjacent leaves also correlated significantly with respect to blade size. Heritability for total leaf‐blade area was high.
Relation of Light Reflectance of Six Barley Lines with Chlorophyll Assays and Optical Film Densities1
Authors: Cardenas R. , Gausman H. W.
Published: July 2010

Light reflectance (R) and chlorophyll (chl) were measured on leaves of three pairs of isolines of barley (Hordeum vulgare L. [H. sativum, Pers.]) to learn if differences in chl concentration among the lines could be photographically detected for remote sensing purposes. Photographs of the plants were taken with Kodak Ektachrome MS Aerographic 2448 (conventional color [CC]) and Kodak Aerochrome Infrared 2443 (CIR) films.

Clorophyll concentrations of the six barley lines were negatively correlated (r −0.87, p = 0.05) with spectrophotometrically measured light reflectance R at the green peak of the 550‐nm wavelength. Golden Liberty had the lowest total chl and the highest R. Liberty and Betzes had the second and third highest chl concentrations (6.70 and 5.65 mg, respectively) and had the lowest R of all lines. Golden Liberty and Betzes had a lower concentration of chl b relative to chl a than the other lines.

Optical count readings made with a densitometer on CC and CIR transparencies were positively correlated with chl concentrations (p = 0.05, 0.88, 0.87, 0.94, and 0.94 for CC film + no filter, CC film + green filter, CIR film + no filter, and CIR film + green filter, respectively).

Discrimination among barley lines was better on CIR than on CC films. With CIR film, highest readings (97.0, no filter and 98.7, green filter) were obtained with Compana, and lowest readings (47.1, no filter and 46.6, green filter) were obtained with golden Liberty.
Nitrate Accumulation in Table Beets and Spinach as Affected by Nitrogen, Phosphorus, and Potassium Nutrition and Light Intensity1
Authors: Cantliffe D. J.
Published: July 2010

The objective of this research was to determine the effects of varying levels of N, P, and K fertilizer and light intensity on nitrate accumulation in species grown for human consumption. In greenhouse experiments, table beets (Beta vulgaris L.) and spinach (Spinacia oleracea L.) were grown in fine sandy loam soil at three levels of N, P, and K fertilizer in a 33 factorial design. Plants were grown under two light intensities, 1.08 ✕ 104 lux or 3.23 ✕ 104 lux. Nitrate, total N, P, and K were determined on freeze dried table beet leaf blades and roots and on spinach leaves.

Fertilizer N had the greatest influence on NO3 accumulation in all three tissues studied. Varying the rate of fertilizer P had no effect on NO3 accumulation. Plants of both species grown with the highest rate of K and under the lower light intensity accumulated significantly more NO3‐N than other plants receiving less K. Table beet leaf blades contained three times more NO3 than roots. Lowering the light intensity from 3.23 to 1.08 ✕ 104 resulted in a significant increase in NO3‐N in all tissues tested.

Total N concentration increased in all tissues with an addition of N fertilizer or by a reduction in light intensity. In spinach, total N was lower in plants receiving K fertilizer. P and K were lower in beet and spinach leaves that received N fertilizer. Light intensity had no influence on P concentration, while all tissues grown at 1.08 ✕ 104 lux contained more K than tissue grown at 3.23 ✕ 104 lux.

Any factor which increased the total N concentration of the tissue resulted in a corresponding increment in the NO3 concentration.
A Photoelectric Seed Counter1
Authors: Fisher H. D. , Brown M. J.
Published: July 2010

Small scale yield studies, germination tests, controlled plantings, and packaging often require the counting of large numbers of seeds. The system described in this paper uses a photosensitive detector and a vacuum pickup to count individual seeds and gives a direct digital readout. The count rate is limited only by how quickly the seeds can be fed through the counting tube without clogging it or having them touch each other. This greatly speeds seed counting, eliminates operator error, and reduces operator fatigue.

With the addition of a relatively simple predetermining circuit, a fixed number of seeds may be counted and a control function can be exercised. This capability is immediately applicable to packaging or repetitious batching of seeds. Zero error for any given number of seeds is attainable if the seeds are fed through the count tube carefully because of the completely digital nature of the circuit.
Corn root‐Configuration Response to Soil Temperature and Matric Suction1
Authors: Allmaras R. R. , Nelson W. W.
Published: July 2010

Soil temperature and water variables imposed on the roots of corn (Zea mays L.) in field plots influenced root development. Responses were measured in separate portions of the root system where adventitious roots initiate and subsequent root elongation and branching occurs. These portions of the corn root system are separated far enough to permit specific field management for each portion. Temperature and water variables were produced by combinations of straw‐mulch strips and interrow tillage.

Initiation of adventitious roots in the 0‐ to 10‐cm soil depth was dominantly influenced by soil temperature in the row.

In soil depths below 10 cm, a functional relation between root configuration and the interrow‐minus‐row soil temperature, and matric suction described the elongation and branching responses subsequent to root initiation. In the year of lower soil temperature and higher moisture (measurements were made in two growing seasons), higher interrow temperatures stimulated branching and elongation, but in the year of higher soil temperature and moderate moisture conditions, responses to temperature were negligible. Higher interrow moisture stimulated branching and elongation in both years as long as the average matric suction was greater than about 85 mb.

These explicit descriptions of corn‐root‐configuration response show the importance of soil temperature management in the row and water management in the interrow. This approach permits more extensive use of the row‐interrow concept for design of minimum tillage and residue management systems.
Response on One Winter Wheat and Two Spring Oat Varieties to Foliar Applications of 2‐Chloroethyl Phosphonic Acid (Ethrel)1
Authors: Brown C. M. , Earley E. B.
Published: July 2010

Ethrel (2‐chloroethyl phosphonic acid) has significant effects on growth and development of corn (Zea mays L.) and soybeans (Glycine max (L.) Merrill) and has been suggested as a potential male gametocide for the production of hybrid wheat. The purpose of this study was to further elucidate the response of winter wheat (Triticum aestivum L. em Thell.) and spring oats (Avena sativa L.) to foliar applications of Ethrel.

Ethrel was foliarly sprayed on the winter wheat variety ‘Knox 62’ at 0.28, 0.56, 1.12, and 2.24 kg/ha when plants were in the late tillering, early boot, late boot, and heading stages. The magnitude of effects was closely related to rate and stage of application. Rates of 0.28 or 0.56 kg/ha applied at early and late boot stages of development effectively reduced height and lodging and in several cases accounted for significant increases in yield. Higher rates (1.12 or 2.24 kg/ha) reduced height and lodging but usually decreased yields when applied at the boot stages of growth. The 1.12 and 2.24 kg rates applied at heading stage did not decrease yield but were less effective in reducing height and lodging. Higher yields in the Ethrel‐treated plots were generally associated with somewhat heavier seeds.

Although we did not bag spikes or observe pollen from treated plants, the excellent seedset we obtained indicated that either the Ethrel treatments did not cause significant male sterility, or if they did, it was completely obscured by cross fertilization. Clearly female fertility was not impaired to any great extent by the Ethrel treatments.

Our results with the same rates and stages of application for two oat varieties suggested that Ethrel has little potential for use on spring oats. Beneficial effects, such as reduced height and lodging, were accompanied by reduced yields. Even the lowest rate of application (0.28 kg/ha) applied at the late boot stage of growth caused a 40% reduction in grain yield. Reduced yields were accompanied by severe blasting of florets. Although the applications made at heading stage did not reduce yields, they were not very effective in reducing height or lodging.
Compatibility of Five Herbicides with a Suspension Fertilizer1
Authors: Meyer L. J. , Murphy L. S. , Russ O. G.
Published: July 2010

The chemical compatibility of five different herbicides (a thiocarbamate, an amide, a thiocarbamate‐triazine mix, a urea‐triazine mix, and an aniline) with a suspension fertilizer (containing 15% N, 6.5% P, and 12.5% K) was studied. Effectiveness of combined materials, applied after being stored in contact for various periods of time, was compared with that of materials applied separately. Nutrient composition (N, P, K), nutrient uptake, and dry matter yields of plants grown in a growth chamber were used to evaluate fertilizer effectiveness. Herbicide phytoxicity was evaluated by visual and pictorial comparisons. Physical compatibility of all mixtures used was determined to ascertain whether the mixtures would mix satisfactorily for field application.

All combined materials were both physically and chemically compatible and all herbicides were as effective when applied in combination with the fertifizer as when applied separately. All herbicides studied can be mixed with the suspension fertifizer prior to application and remain effective during the growing season, but agitation is required during storage.