bluuebunny/crossref_metadata_2025 huggingface dataset:
Yield Response of Pangolagrass Grown on Tiwiwid Fine Sand to Mg and Fritted Micronutrients1
Authors: Chesney H. A. D.
Published: July 2010

With the recent availability of 30,000 ha of Tiwiwid fine sand (Type Quartzipsamment), a highly leached, excessively permeable, coarse‐textured soil of poor natural fertility, it was necessary to evaluate the potential of this marginal soil for sustained agricultural production.

The effect of Mg and Fritted micronutrients (FTE 503)—singly and in combination—on the dry matter yield of pangolagrass (Digitaria decumbens Stent) was studied over an 18‐month period by means of a 32 factorial experiment. The variables of Mg and FTE 503 were 0, 88, and 176 kg/ha/annum of MgO and FTE 503, respectively, applied in four equal increments at 12‐week intervals. Yields were measured by cutting the grass at regular intervals.

Magnesiumd id not have a positive effect on yield at any harvest and actually depressed yields at some harvests. Magnesium ✕ micronutrients interaction was also non‐significant.

Up to 88 kg/ha/annum of FTE 503 generally and 176 kg/ha/annum during periods of heavy rainfall increased yields at all harvests, with the effect becoming progressively greater with time. Some micronutrient deficiencies were observed on the grass that did not receive micronutrients. Over the 18‐month period FTE 503 increased total dry matter yield by 8,700 kg/ha over the control.
Missing Hills in Rice Experimental Plots1
Authors: Gomez K. A. , De Datta S. K.
Published: July 2010

The effects of missing hills on the performance of the surrounding plants were investigated in a series of rice (Oryza satlva L.) field experiments under several conditions. Plants immediately adjacent to a missing hill were found to have significantly more panicles and higher yield than plants surrounded by living hills. The magnitude of the increase, however, varied with variety, plant spacing, fertility level, crop season, and the number and the distribution of missing hills. The stand correction method is therefore not applicable to rice. To determine yields of plots wtih missing hills, only fully competitive plants should be harvested.
A New Approach to Phenological Research — Relationships Between Environmental Factors and Days to the Appearance of the First Leaf in Four Perennial Species1
Authors: Benacchio S. S. , Blair B. O.
Published: July 2010

Plant‐climate‐soil relationships were studied during the years 1968 and 1969 on the basis of the phenological pattern of appearance of the first leaf in spring of four perennial species, spirea (Spirea spp L.), orchardgrass (Dactylis glomerata L.), fall aster (Aster azureus L.), and big blue stem (Andropogon gerardi L.). Plantings of these species were previously established in plots adjacent to official weather stations at all five locations in Indiana. Comparisons between the environmental factors and the appearance of the first leaf were made using two multiple regression analysis methods. First leaf appearance during the 2 years did not follow Hopkins' bioclimatic law at these locations. In a northern Indiana muck soil at Wanatah, the growing season began 6 to 10 days later in the 1969 year than on a sandy loam soil located only 250 m from that location. Appearance of the first leaf at all locations for the four species over both years was 2 or 3 weeks earlier at the southern location than on the heavier soils in central and northern Indiana. Regression analysis show that six parameters contributed to much of the R2 value, with each independently contributing to a high R2 value. The regression included those factors that would develop R2 values to .9000+. Parameters consistently contributing to this value were daylight hours and soil temperatures at 20, 5.0, and 2.5 cm (base OC bare soil).

Daylight hours from the last frost to first leaf were the most consistent parameter correlated with appearance of the first leaf. Soil temperature at 20 cm was also important and contributed to increasing R2

Soil differences, based on detailed physical and chemical analyses, accounted for plant response variation indirectly, especially as related to texture that influenced water‐holding capacity and subsequently temperature.

This is an interesting parameter as it relates to soilplant‐climate interactions in heavy‐textured soils. The correlation for soil and air temperature relationship was linear. Degree‐day accumulation was different in the 2 years, indicating that other factors, such as the soil temperature‐moisture interaction, minutes of sunshine, net radiation, etc., may be important environmental parameters involved in initiation of plant growth in the spring as indicated by the appearance of the first leaf.
Subterranean Clover (Trifolium subterraneum L.) Yield and Nutrient Content as Influenced by Soil Molybdenum Status1
Authors: Dawson M. D. , Bhella H. S.
Published: July 2010

Experiments were initiated to elucidate the effect of Mo application on subterranean clover with respect to yield and nutrient status and to examine an anion exchange resin as a means of assaying plant available Mo.

Highly significant yield and relative total N uptake of subterranean clover (Trifolium subterraneum L.) were obtained following Mo fertilization in greenhouse studies and field trials conducted on hill soils of western Oregon. Generally greatest relative yield as well as relative total N uptake from applied Mo occurred at the lower anion exchangeable soil Mo levels. There was no significant change in plant Cu concentration following Mo fertilization. However, Mo treated soils produced clover somewhat higher in Mo concentration than untreated soils. Cu concentration in clover appeared sufficiently high relative to the Mo concentration to present little chance of nutritional disorders in ruminants.
Animal Preference and Utilization of Selected Forage Sorghums Grazed in Fall and Winter1
Authors: Rieck W. L. , Croy L. I. , Davies F. F.
Published: July 2010

This study was initiated to determine forage quality and animal utilization of eight forage sorghum types (Sorghum bicolor (L.) Moench.) in situ after frost. Planting date was late to insure that plants would be in the boot to bloom stage by killing frost thus providing high yields of medium to high quality forage.

As winter progressed, the available forage, percent digestion, and percent utilization declined for all types. The protein content was not affected during the winter season, but the percent dry matter increased with time. ‘Sugar Drip’ was consistently higher in the amount of forage utilized, in vitro dry matter digestion, and moisture content throughout the winter. ‘Pioneer 931’ produced higher yields than any other type, but was not used as efficiently as some of the other types.

The research indicated that it is feasible to graze cured forage sorghums for maintenance rations with reasonably low costs in areas where the winters permit.
A Miniature Strip Net Radiometer1
Authors: Harper Lowry A.
Published: July 2010

An inexpensive miniature strip net radiometer was constructed for average net radiation measurement along a horizontal line in dense foliage such as short grasses or row crops. The sensing surface was 1.3 ✕ 40 cm and was enclosed in a polyethylene shield for protection against wind and weather. The unit was calibrated relative to a temperature‐compensated, net‐exchange radiometer, and gave a linear response.
Variation of Soluble Phenolic Compounds in Flue‐cured Tobacco Cultivars with Stalk Position1
Authors: Andersen R. A. , Tso T. C. , Chaplin J. F.
Published: July 2010

Phenolic levels in field‐grown flue‐cured leaves of ‘Coker 139,’ ‘NC 95,’ ‘SC 58,’ and ‘LN 38’ were compared within each cultivar according to leaf positions on the stalks and among the four cultivars. Each of the cultivars showed a significant but generally nonlinear increase in levels of total phenolics (about 2‐fold for each) and sums of chlorogenic acids and rutin (2 to 9‐fold depending on cultivar) with eight ascending leaf positions on the stalk from lower to upper leaves. However, mean values of total phenolic reducing power equivalent to a chlorogenic acid standard and averaged over all stalk positions ranged from 7.17% in Coker 139 to 7.92% in NC 95; these values were not significantly different among the cultivars. Likewise, means of the sums of chlorogenic acids and rutin averaged over all leaf positions on the stalk ranged from 120% in Coker 139 to 1.59% in NC 95, and the four cultivars were not significantly different. Total soluble phenolic compounds were estimated by their bonding to insoluble polyvinylpyrrolidone at pH 3.5. Chlorogenic acid isomers and rutin were determined by electron capture gas chromatographic analysis based upon the amount of soluble caffeic acid and quercetin moieties found. Leaf phenolic compounds affect color and quality and may contribute to the tumor‐promoting weak acid fraction of tobacco (Nicotiana tabacum L.) smoke condensate. Therefore, leaves of these cultivars from different positions on the stalk will be used for cigarette manufacture to correlate the phenolic‐stalk position findings with smoke characteristics and composition.
Plant Density Effect on Grain Yield of Corn Hybrids Diverse in Leaf Orientation1
Authors: Hicks D. R. , Stucker R. E.
Published: July 2010

Corn (Zea mays L.) yields have increased when corn plant leaves are more vertically oriented compared to normal corn leaf habit, but there is little information on yield effect of plant density changes in corn genotypes that have erect leaf orientation. This work was conducted to evaluate the grain yield response to plant density of corn hybrids diverse in leaf orientation.

Eighteen corn hybrids differing in leaf orientation were grown at five densities in 1969 and 1970. Data recorded were grain yield; ear moisture; and angle, width, and length of the leaf above the ear.

In both years hybrids differed significantly for yield, leaf angle, leaf width, leaf length, and length to the breakpoint of the leaf above the ear and densities differed for yield, leaf angle, leaf width, and leaf length (1969 only). Yield and leaf angle (small angle characterizes uprightness) were negatively correlated at low populations; the correlation approached 0 as plant density increased.

Hybrids were grouped on the basis of leaf angles and yield response to population in 1970. When groups differed in leaf angle, the linear regression coefficients of yield on density did not differ statistically. However, there was a statistical difference between linear regression coefficients, with no difference in mean leaf angles, when hybrids were grouped by yield response to population.
Effect of Day/Night Temperature on Seedling Establishment of Nicotiana tabacum L. in Controlled Environments1
Authors: Haroon Mohammed , Long R. C. , Weybrew J. A.
Published: July 2010

The trend toward mechanized planting or transplanting of tobacco necessitates that seedling establishment (germination and initial growth to the first leaf stage) occur rapidly, at a uniform rate, and at high percentage. The effect of nine day/night temperature combinations on seedling establishment of flue‐cured tobacco, Nicotiana tabacum L. ‘NC 2326,’ was studied under controlled conditions. Seeds were sown and germinated in temperature‐controlled greenhouses, and daily counts were made to determine the number of seedlings whose first leaf had emerged. Little difference in total seedling establishment (percentage) or in uniformity of rate (standard deviation of the mean days‐to‐establishment) was found between the 26/26, 26/22, 22/22, and 22/18 C day/night temperature treatments. The rates of seedling establishment (mean days‐to‐establishment) between most treatments were different. Day/night temperatures of 26/22 C resulted in the best overall response with respect to total, rate, and uniformity of rate of seedling establishment.
Expectations, Variances, and Sensitivity of Net Returns from Corn Fertilization Experiments1
Authors: Ogut Cevdet , Doll John P. , Kroth Earl M. , Colyer Dale
Published: July 2010

Many experiments designed to provide data for estimating production response surfaces have been conducted for only one year and as a result, the findings were applicable to only one set of environmental conditions. To obtain more general results a series of experiments measuring corn (Zea mays L.) yield response to applied N and plant population were conducted at three locations for several years in northern Missouri. Expected profit functions were estimated for each experiment and the input amounts that would have maximized profits for the time period of the experiments were derived. The resulting amounts (expected optima) were 197 kg of N and 45,360 plants/ha for Grundy County, 140 kg of N and 40,488 plants for Saline County, and 135 kg of N and 34,455 plants in Boone County. These amounts were lower than many of the annual optima. Furthermore, expected profits over the experimental periods were relatively insensitive to departures from the annual optima. Additional analyses determined input rates that (i) minimized the cost or (ii) minimized the variance of a fixed expected profit level for the period. Expected profits from many of the annual optima could have been produced at substantially lower cost. Compared to cost minimization, variance minimization increased N and reduced stand; although N is more expensive than plant population, it “costs less” in terms of variance. Expected profits were quite sensitive to corn price and, to a lesser degree, N price; optimal inputs were much less sensitive to these same prices.
Nitrate‐N Accumulation in the Soil Profile Under Alfalfa1
Authors: Schertz David L. , Miller D. A.
Published: July 2010

A study was conducted to determine the influence of various levels of ammonium nitrate applications of NO3‐‐N accumulations under alfalfa (Medicago sativa) and whether alfalfa has the ability to utilize excessive amounts of nitrate in the soil. Eight split applications of N totaling 0, 224, 448, and 672 kg/ha (0, 200, 400, and 600 pounds/acre) were studied at the Agronomy South Farm, Urbana, Ill. at various depths on six sampling dates. Soil was sampled at depths of O to 15, 15 to 30, 30 to 60, 60 to 90, and 90 to 105 cm or to the water table, which was never lower than 105 cm. Soil samples were dried, finely ground, and analyzed for NO3‐‐N. NO3‐‐N concentrations were greatest in March 1970 at the 30‐ to 60‐cm depth. No more than 1 ppm was found at the 90‐ to 105‐cm depth (water table) for any N treatments on Nov. 11, 1970. Highest concentrations of NO3‐‐N were found at the 15‐ to 30‐cm depth for all N treatments at the end of the growing season, Nov. 11. Although total amounts of NO3‐‐N were lower in March than in November, the highest accumulations were found at the 30‐ to 60‐cm depth in March, but at the 15‐ to 30‐cm depth in November. The only treatment on Nov. 11 that did not show a significant difference when compared to the check was the 224 kg N/ha. Alfalfa would have some value in a rotation for reducing NO3‐‐N, which may accumulate under continuous corn (Zea mays L.) after excessive N applications.
Response of Irrigated Corn to Time, Rate, and Source of Applied N on Sandy Soils1
Authors: Jung P. E. , Peterson L. A. , Schrader L. E.
Published: July 2010

To maximize N recovery by corn (Zea mays L.) on irrigated sandy soils, establishing the proper time for and rate of N application are essential. Three sources of N (urea, NH4,NO3, and KNO3) were applied to corn at four rates (56, 112, 168, and 224 kg/ha of N) and six times application in all combinations. ‘Wisconsin 273’ (85 R.M.) and ‘Wisconsin 433’ (95 R.M.) were grown. Response was measured as grain yield, tissue yield (aerial portion at early dent), percentage N in tissue, percentage N in grain, and N uptake The N applied during either the 5th, 6th, 7th, or 8th week after planting was the most effective as shown by increased grain and tissue yields. Nitrogen applied after the 8th week was associated with a distinct reduction in N uptake and grain and tissue yields. Generally, percentage N in the grain and tissue increased with later N applications. The responses to urea and NH4NO3 were similar and both sources were sig~fificantly better than KNO3. Nitrate reductase (NR) activity in the leaves and percentage N in grain and tissue increased with increasing rate of applied N. Yields of grain and tissue for Wisconsin 273 and Wisconsin 433 leveled off at the 112 and 168 kg/ha rates of N, respectively.
Survival and Emergence of Volunteer Castor Seed in Soil1
Authors: Smith D. T.
Published: July 2010

Volunteer castor (Ricinus communis L.) seedlings are a severe weed problem in crops grown after castor. Emergence and development of castor were investigated in the greenhouse and field to determine if certain cultural practices would reduce the abundance of volunteer castor seedlings. Castor seed remaining on soil after harvest of dwarf‐internode hybrids ranged from 52,000 to 2,260,000 seeds/ha. Seedling emergence was lower when exposed castor seed were subjected to high rainfall (20 cm) during the winter. Seedling emergence was higher the following spring when rainfall was low after harvest. There was no difference in emergence from seed planted in January to May. Plant height and foliar development were suppressed, however, when exposed seed were planted later, indicating that seedling vigor would be lower if soil preparation were delayed after castor harvest. Castor readily emerged from seed planted 20 cm deep in a greenhouse or in the field. Maximum emergence was 84% from seed planted 10 to 20 cm deep in warm sandy loam. Consequently, volunteer castor populations in subsequent crops would be lowest following moist winters and delayed, shallow coverage of seed.
Effects of Selected Herbicides on Annual Weed Control and Production of Processing Peas1
Authors: Harvey R. G. , Gritton E. T. , Doersch R. E.
Published: July 2010

Little information is available regarding the effects of herbicides on annual weeds in processing peas (Pisum sativum L.) and on the peas themselves. Therefore, field experiments were conducted over a 2‐year period to assess the relationship between annual weed control with herbicides and pea production. Herbicide treatments of α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine (trifluralin), 2‐chloro‐2,6‐diethyl‐N‐(methoxymethyl)acetanilide (alachlor), 2‐chloro‐N‐isopropylacetanilide (propachlor) 2‐(4‐chloro‐6‐ethylamino‐s‐triazine‐2‐ylamino) ‐2‐methylproprionitrile (cyanazine), [(4‐chloro‐o‐tolyl)‐oxy] acetic acid (MCPA), 4‐[(4‐chloro‐o‐toyly)‐oxy] butyric acid (MCPB), and MCPB plus 2,2‐dichloropropionic acid (dalapon) were applied to ‘Alaska‐’ and ‘Perfection’‐type pea cultivars. Satisfactory control of most grass and broadleaf weeds was obtained with trifluralin, alachlor, propachlor, and cyanazine. MCPA and MCPB gave partial control of broadleaf weeds but did not improve pea yield. The combination of MCPB and dalapon gave moderate weed control and subsequent moderate yield increases in the Perfections. Significant reduction in stands of both Alaska and Perfection peas resulted from trifluralin application; substantial reduction in shelled‐pea yield, however, occurred only in the Alaska. Severe injury to pea plants was caused by cyanazine in 1970, but not in 1971 when abnormally low rainfall was received. No injury to pea plants was observed from applications of either alachlor or propachlor. Under the conditions tested propachlor at 5.6 kg/ha and the combination of dalapon and MCPB at 1.1 and 0.8 kg/ha provided the most satisfactory annual weed control with the least risk of crop injury.
Influence of Harvest Method on In Vitro Dry Matter Disappearance of Alfalfa and Orchardgrass1
Authors: Shenk J. S. , Cook A. F.
Published: July 2010

A study was undertaken to evaluate the influence of harvest method on forage quality. Alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) forages harvested in the long form were, respectively, 8.0 and 5.0% higher in in vitro dry matter disappearance (IVDMD) than flail‐chopped forage. The flail‐chopped alfalfa forage had higher apparent cell wall concentration, less cell wall hemicellulose, and more cell wall lignin. Flail‐chopped orchardgrass samples had less cell wall hemicellulose and more cell wall lignin. Hand‐harvested samples of both species dried at a faster rate than the flail‐chopped samples. Differences in rate of drying were believed responsible for the changes in forage composition and IVDMD. Caution should be used when comparing the quality of forage samples harvested by different methods.
Soil Temperature Reduction During Pollination and Grain Formation of Corn and Grain Sorghum1
Authors: Adams John E. , Thompson D. O.
Published: July 2010

Factors other than total seasonal rainfall may be affecting corn (Zea mays L.) and possibly grain sorghum [Sorghum bicolor (L.) Moench] yield in central Texas. It has been suggested that high temperatures in central Texas during pollination and grain filling decrease the carbohydrate reserves of corn. Soil temperature was lowered in corn and grain sorghum plots during pollination and grain formation to observe the effect of soil temperature during this critical period on grain yield. Chilled water (12 to 14 C) was circulated through copper tubing 11 cm below the soil surface in plots 6.1 m long and 4.0 m wide located on Houston Black clay soil. Soil temperature in the upper part of the root zone (7.5‐ to 46‐cm depth) during soil cooling averaged 23 C in mulched, cooled grain sorghum plots; 22 C in mulched, cooled corn plots; and 26 C in bare, noncooled corn and grain sorghum check plots.

Decreasing average soil temperature (7.5‐ to 46‐cm depth) during pollination and grain formation from 26 to 23 C reduced grain sorghum yield, but reducing average soil temperature to 22 C had no effect on corn yield. Soil cooling caused a significant (5% level) decrease stem temperature to a height of 61 cm in corn and some stem cooling at 61 cm in grain sorghum. Stem cooling of both corn and grain sorghum decreased with distance above the soil surface. Yield data obtained indicate that soil temperature during pollination and grain filling is not a factor limiting grain yield of corn and grain sorghum in central Texas.
Influence of Cropping System on Salt Distribution in an Irrigated Vertisol1
Authors: Hipp Billy W. , Gerard C. J.
Published: July 2010

Field studies were conducted to determine the influence of cotton (Gossypium hirsutum L.) and grain sorghum [Sorghum bicolor (L.) Moench.] on salt distribution in a vertisol profile. Electrical conductivity of soil saturated pastes taken from the root zone (0 to 90 cm) after 4 years of sorghum ranged from 2.6 to 4.8 mmhos/cm but ranged from 4 to 7.6 mmhos/cm at 0 to 90 cm after 4 years of cotton. Chloride concentrations showed similar trends in that CI‐ concentrations were 9 to 12 meq/liter at 0 to 90 cm after sorghum, but were from 18 to 30 meq/liter at the same depth after cotton. The differences in salt concentrations in the soil profile after the two crops were attributed mainly to higher water infiltration rate after sorghum (5.81 cm/hr) than after cotton (1.23 cm/hr). The indicate that cropping practice can be an important factor in salt accumulation in clay soils and that the crops should be alternated to avoid excessive salt accumulation in the root zone.
Competition Between Established Tree Roots and Newly Seeded Kentucky Bluegrass1
Authors: Whticomb Carl E. , Roberts Eliot C.
Published: July 2010

Landscape situations frequently are such that trees may be well established when an attempt is made to establish turf. This occurs when renovating an old lawn, changing type of turf, or where new subdivisions are located in areas of established trees. This study was initiated to assess the effects of established silver maple (Acer saccharinum) and honey‐locust (Gleditsia triacanthos L.) roots on newly seeded Kentucky bluegrass (Poa pratensis). A connecting pot technique was used to maintain nearly uniform light intensity over tree‐shaded pots with or without tree roots.

Silver maple and honeylocust roots established prior to seeding of common Kentucky bluegrass had a highly significant effect on growth of bluegrass, but the bluegrass had no significant effect on tree roots. Dry weight of foliage, sod and root yields, and root/sod ratios were reduced by presence of tree roots. Penetration of bluegrass roots into the main soil mass was restricted by silver maple roots. A mat of bluegrass roots about 0.95 cm (⅜ inch) thick was easily lifted from the soil containing tree roots.

Established tree roots reduced the number of bluegrass plants established from seed, but had no effect on tiller production. It is hypothesized that biochemical inhibition (allelopathy) may be involved.
Laboratory Evaluation of Quality in Subtropical Grasses: I. In Vitro Digestion of Entire Plant vs Apical Meristem Portions of Digitaria1
Authors: Schank S. C. , Ventura M. , Moore J. E.
Published: July 2010

Two sibling genotypes of a Digitaria hybrid were harvested over five regrowth periods in order to compare in vitro organic matter digestion (IVOMD) and to determine methods of sampling sub‐tropical grasses. Entire top growth and apical meristem portions were collected at 3, 5, 7, 9, and 11 weeks of fall regrowth using four field replications of each genotype. The IVOMD of the apical portion remained relatively constant over a 6‐week period, being 67.6% at 5 weeks and 67.5% at 11 weeks, indicating that the apical portion is in a comparable “physiological age” regardless of date of cut. The entire top growth decreased in IVOMD from 69.7% at 3 weeks to 61.6% at 11 weeks. Significant differences (5% level) between the two hybrids were detected at the 5‐week harvest date.
Relationships between Drouth and Corn Yields on Selected South Atlantic Coastal Plain Soils1
Authors: Sopher Charles D. , McCracken Ralph J. , Mason David D.
Published: July 2010

The objectives of this study were to determine the effects of drouth‐days by physiological growth periods on corn (Zea mays L.) grain yields and to develop a onefigure drouth index suitable for expressing these effects. A drouth‐day was defined as a 24‐hour period when potential evapotranspiration exceeds rainfall plus the effective moisture storage capacity. The physiological growth periods were: two equal‐length periods prior to tasseling; tasseling; and a maturity period. The study was conducted on two major North Carolina Soil Groups.

On the better drained (Udultic) soils of the Upper and Middle Coastal Plains, drouth‐days accounted for 62.6% of the corn yield variation. The effects of drouth were detrimental in the second and fourth growth periods, and grain yields were reduced to zero after five drouth‐days during the tasseling period. For the very poorly drained (Aquultic) soils of the Tidewater Region, drouth‐days accounted for 41.2% of the yield variation. Detrimental drouth‐day effects were only present during the second and tasseling periods. The reduction of the effects of drouth‐days on these soils was attributed to moisture extration from an underlying water table.

Using the derived regression coefficients for weights, the drouth‐days by physiological growth periods were weighted and summed to develop a one‐figure drouth‐index. This index may be used as a single climatic variable in regression‐correlation studies of the crop‐soil ecological system.
Aerodynamic and Energy Balance Comparisons Between Awned and Nonawned Barley1
Authors: Benci J. F. , Aase J. K. , Ferguson A. H.
Published: July 2010

The objective of the study was to evaluate the influence of awning characteristics of barley (Hordeum vulgare L.) on the partitioning of the heat load and the turbulent characteristics of the lower atmospheric boundary associated with the plant canopy. Aerodynamic studies of full‐awned, half‐awned, and nonawned isogenic barley indicated that awns increased the roughness length for the barley canopy. Increased turbulence over the full‐awned canopy increased the air‐sensible and latent heat fluxes. After awn emergence, net radiation was approximately 100 ly/day higher over the full‐awned than over the other two isogenic lines. Between 80 and 100% of the increased net radiation was dissipated by air‐sensible heat flux.
Temperature Variation Within and Between Rooting Media in Plant Growth Chambers1
Authors: Knievel Daniel P.
Published: July 2010

Controlled environment chambers are commonly used to study influence of microclimatic variables on plant processes. An often neglected variable in these studies is temperature of the root zone. Diurnal temperature patterns of soil at 2 and 5 cm and sand at 5 cm in a cool regime (16.8C day/12.8C night) and of soil at 2 and 5 cm and nutrient solution in a warm regime (37.8C day/31.2C night) were measured. Root zone temperatures in the cool regime were higher than air temperatures during the day and cooler at night. Temperatures of the root zone in the warm regime were lower than air temperature during both day and night periods. These data call attention to diferences in root zone and air temperature which can occur during temperature controlled environmental studies.
Flax Growth in Cecil Soil Containing Mordant Violet 391
Authors: LaFleur K. S. , Craddock G. R.
Published: July 2010

The purpose of this study was to determine if addition of a metalizable anionic dye to a phosphate‐fixing soil would release phosphate for plant consumption. Some evidence of phosphate release was obtained.

Addition of Mordant Violet 39 to Cecil surface soil increased flax growth in this soil. In a growth chamber experiment incorporating the dye, plant height increased about 40%, planet weight increased about 60%, and plant phosphorus increased about 100%.

The dye‐grown flax was necrotic. It contained more manganese and less calcium and magnesium than control flax.
Influence of N Fertilization and N Carryover on Yield and N Concentration of Dactylis glomerata L.1
Authors: Donohue S. J. , Rhykerd C. L. , Holt D. A. , Noller C. H.
Published: July 2010

The feasibility of increasing N rates on forage grasses, brought about by low cost commercial N fertilizer, has focused attention toward the effects of high N levels on grass development and production and the hazard of ground water pollution where the applied N is not completely utilized by the forage. A 3‐year study was initiated to investigate the effects of N fertilization and N carryover on dry matter yield and percent N in orchardgrass (Dactylis glomerata L.) and to determine the N rate that would give minimal pollution problems. The N treatments, 0, 84, 168, 336, 672, and 1344 kg/ha/year of N were applied for 2 years previous to the experiment. With the initiation of the study, plots were split, half receiving N treatment and half receiving no N fertilization.

Dry matter yield was found to increase up to 336 kg/ha of applied N. At the higher N rates, yields leveled off or declined, apparently due to stand reduction. Nitrogen fertilization also increased total N content of orchardgrass.

Response of orchardgrass to N carryover the first year of the residual study, as measured by dry matter yield, was found at residual N rates greater than 84 kg/ha. Nitrogen carryover during the second year was observed only at the 672 and 1344 kg/ha residual N rates, and only at the 1344 kg/ha residual N rate the third year of the study. Nitrogen carryover affected total N content only in the first year of the study and only at the two highest residual N rates.

Over a 5‐year period, N application equaled N removal at 246 kg/ha/year of applied N. Above this rate, N carryover was observed. This study indicates that on Crosby silt loam soil, approximately 250 kg/ha of N should be applied per year on orchardgrass in central Indiana.
Effect of Site of Exposure to Nitrapyrin and 6‐Choropicolinic Acid on Growth of Cotton and Wheat Seedlings
Authors: Geronimo J. , Smith L. L. , Stockdale G. D.
Published: July 2010

Nitrapyrin (2‐Chloro‐6‐(trichloromethyl) pyridine) is a selective nitrification inhibitor and 6‐chloropicolinic acid is its principal metabolite in plants and soil. Nitrapyrin has been found to produce more phytotoxicity on some graminaceous species than 6‐chloropicolinic acid, and the opposite has been found for some dicotyledenous species. This study was conducted to determine if the differences in activity observed with nitrapyrin and 6‐chloropicolinic acid on some monocotyledenous and dicotyledenous species could be due, at least in part, to differences in the site of exposure of the seedlings to the two chemicals. Chemically treated bands of soil were placed either above or below the seeds of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.), and the effect of the chemicals was assessed by weighing top growth of the plants. Nitrapyrin reduced the top growth of both cotton and wheat when exposure occurred through both the roots and shoots of the germinating seedlings. 6‐Chloropicolinic acid reduced the top growth of both species when exposure occurred through the roots only. The site of exposure of the germinating seedlings to the chemicals influences the degree of phytotoxicity obtained. The inherent activity of each compound against each species, however, appears to be a more important factor with regard to phytotoxicity.
Effects of Cutting Management on a Desmodium intortum (Mill.) Urb / Setaria sphacelata (Schumach.) Mixture1
Authors: Olsen F. J.
Published: July 2010

A study was conducted to determine the influence of two heights (8 and 20 cm) and three frequencies of cutting (3, 6 and 9 weeks) on the yield, botanical composition, and nutritive value of Desmodium intortum (Mill.) Urb grown in association with Setaria sphacelata (Schumach.). The mixture was established on a latosol soil at Kabanyolo, Uganda. Herbage samples were hand separated to ascertain botanical composition. Crude protein (CP) and in vitro dry matter (IVDM) analyses were determined for each species for all cutting treatments.

Annual dry matter yields of the mixture ranged from 5.67 to 14.97 mt/ha. The productivity of the mixture was enhanced as the tune of the cutting interval increased. No notable yield differences were found between cutting heights.

Close frequent clipping had a deleterious effect on D. intortum. The slow recovery of this legume after close cutting led to a rapid increase in the grass and weed components.

The CP content of D. intortum was more than double that of S. sphacelata. There were significant differences in CP content among cutting irequencies in S. sphacelata. As the time of the cutting interval increased, the CP content decreased.

In vitro dry matter digestibilities of S. sphacelata varied from 61.9 to 68.2%. As the time of the cutting interval increased, the IVDM percent digestibilities of S. sphacelata decreased. There were no notable differences among IVDM digestibility percentages of D. intortum.

This study demonstrated that the productivity and persistence of D. intortum were greatly influenced by the clipping treatments applied. Results clearly indicated that proper cutting management is needed in order to maintain the legume in the mixture. Long cutting intervals (6 to 9 weeks) at 20‐cm height were essential to keep D. intortum in adequate amounts when grown in association with S. sphacelata. The CP percent and degree of in vitro digestibility indicated that a balanced D. intortum/S. sphacelata mixture would adequately meet the nutritional requirements of grazing animals.
Siduron Toxicity to Turfgrasses as Affected by Several Climatic Factors1
Authors: De Mur Antonio R. , Youngner V. B. , Goodin J. R.
Published: July 2010

Because siduron is absorbed by roots and transported by the transpiration stream, its phytotoxicity might be affected by environmental factors that influence transpiration. To test this, bermudagrass (Cynodon dactylon L. ‘Santa Ana’) and Kentucky blue‐grass (Poa pratensis L. ‘Merion’) were grown in controlled‐environment chambers at various temperatures and light intensities and treated with 1 and 5 ppm siduron. Untreated plants were also included. Bermudagrass was susceptible to 1 and 5 ppm siduron concentrations at all temperatures and light intensities. Shoot growth was reduced more than root growth. When air temperature was 30/20 C (day/night) the toxicity of the herbicides was greater than at a lower air temperature (22/15 C). Low light intensity decreased the toxicity of siduron to bermudagrass. Bluegrass was tolerant at all concentrations and all temperature and light treatments. Root temperature did not affect toxicity of the herbicide but maximum growth of bermudagrass was at 20 C and Kentucky blue‐grass at 15 C root temeprature. At 10 C, growth of both species was distinctly reduced. Differential rates of absorption are not the basis for selectivity.
Cultivar Differences Among Triticale Seedlings Treated with Various Growth Regulators1
Authors: Cole D. F.
Published: July 2010

Seedlings of four triticale (proposed scientific name Triticale hexaploide Lart.) cultivars were grown in vermiculite with continuous light at 20 ± 1 C from seed that had been treated with various growth regulators during imbibition prior to planting. The objectives were to determine useful characteristics in cultivar identification and the effect of various growth regulators on growth and development of triticale. Growth regulators tested were: gibberellic acid (GA3); (2‐chloroethyl) trimethyl ammonium chloride (CCC); Tris‐(2‐diethylaminoethyl)‐phosphate trihydrocloride (SK & F 7997‐A3); and a water control.

All parameters, percent emergence, internode length, dry weight, and length of leaves 1, 2, and 3, were significantly affected by cultivars and growth regulators. A chemical & cultivar interaction was evident in length of the first internode and length of leaf 1. Internode length in the winter cultivars was significantly increased, whereas only one of the spring types responded to GA. The data indicate that certain cultivars could be distinguished from other cultivars in controlled environments when the seedlings are grown with and without growth regulators.
Chemical Properties of Tobacco Leaves as Affected by Carbon Dioxide Depletion and Light Intensity1
Authors: Raper C. David , Weeks W. W. , Downs R. J. , Johnson W. H.
Published: July 2010

Plants growing in controlled‐environment rooms are frequently subjected to self‐depleted CO2 levels that manufacturers' “make‐up air systems” do little to alleviate. Flue‐cured tobacco (Nicotiana tabacum L. ‘Coker 319’) rapidly depletes CO2 from a 400 ppm (μl/liter) ambient level of 200 ppm. When compared with plants grown to maturity in an atmosphere continually adjusted to the 400 ppm level by supplementary CO2, chemical assays of leaf constituents indicated lesser effects of the CO2 depletion than anticipated. The contents of starch, soluble carbohydrates, and polyphenolics were meagerly depressed in a CO2‐depleted atmosphere. A reduction in light intensity below 322 hectolux had a greater effect accumulation of these compounds than did CO2 depletion, The CO2 depletion did affect the composition of the soluble carbohydrate fraction in leaf tissue.

The CO2 and light treatments in this experiment were continued until au advanced stage of leaf senescence. Both CO2 depletion and reduced light intensities prolonged the growth period of leaves before the onset of senescence. We conclude that the extended period of growth, as well as the chronological timing of other morphological eve:ats, explains many of our reported results.
Choice of Irrigation Timing Indicator for Narrow Row Cotton1
Authors: Bordovsky D. G. , Jordan W. R. , Hiler E. A. , Howell T. A.
Published: July 2010

This irrigation study was undertaken to compare water use efficiencies (WUE) resulting from three methods of timing water applications on narrow‐row cotton (Gossy‐pium hirsutum L.). Irrigation timing during the 1971 and 1972 growing seasons was accomplished using the soil water potential (SWP)‐fixed level, leaf water potential (LWP)‐fixed level, and stress day index (SDI)‐vari‐able level of LWP, based on crop sensitivities, as indicators. Specific levels of each indicator were selected so that nearly identical yields would result for all three timing indicators, thus making possible the valid comparison of WUE. With the SWP indicator as a basis for comparison, higher WUE were obtained with the LWP and SDI indicators in both years. At a plant population of 150,000 plants/ha, average increases in WUE (seed cotton yield divided by irrigation plus rainfall amounts) were 17 and 38% for the LWP and SDI indicators, respectively. Average increases when WUE was calculated as yield divided by irrigation amount only were 30 and 82%, respectively. The increases in WUE were due to reductions in irrigation amounts rather than increases in yield. These results demonstrate that significant benefits in stretching irrigation water supplies are possible when using plant‐based measurements and when plant sensitivities at different growth stages are quantitatively considered in timing irrigations.
Hail Damage to Upland Cotton1
Authors: Peacock H. A. , Hawkins B. S.
Published: July 2010

There has been very little scientific data published on the effect of hail damage on Upland cotton (Gossypium hirsutum L.) because of the nature of the problem and difficulty in setting up an appropriate, experimentally sound investigation.

A hailstorm on June 26, 1971 made it possible to collect data on the effect of differential damage to individual Upland cotton plants. Three injury classes were established: 1) slight — some stem and leaf damage; 2) moderate — terminal bud lost plus some leaf and stem damage; 3) severe — terminal bud lost plus extensive stem and leaf damage. Effects of hail damage were determined by tagging 5 plants per injury class within each of 10 replications of 5 cultivars. Data were obtained from each of the five plants per injury class for each of the characteristics reported.

An application of 47 kg/ha additional N after the hailstorm did not increase the yield of cotton. The lack of response to N, however, may have been caused by the 78 kg/ha N applied before the hail damage occurred. This amount of N is usually adequate for cotton grown on Cecil sandy loam. The number of productive plants was significantly higher in the slight‐ and moderate‐injury classes than in the severe class. As injury increased, individual plant yield decreased significantly in a ratio of 5:3:1 for the slight, moderate, and severe classes, respectively. Plants in the severe‐injury class had a lower lint percentage than plants in slight‐ or moderate‐injury classes. There was no significant effect on fiber length or strength, but finer fibers were produced by plants in the severe‐injury class.
Instrument for Measuring Forces and Energies Associated with Physical, Properties of Biological Materials1
Authors: Friesen James A. , Bilbro J. D.
Published: July 2010

An instrument that can accurately and rapidly measure the forces and energies associated with certain physical properties of biological materials (e.g., breaking strength of stems) was designed and built. Loading force applied to the material and movement of the force‐loading device are recorded simultaneously. From these measurements, energy quantities can be calculated. Means for readily changing force‐loading speeds and rapidly returning the force‐loading device to its starting position are provided.
Effects of Spacing and a Growth Regulator, Kylar, on Size and Yield of Fruit of Virginia‐Type Peanut Cultivars1
Authors: Wynne J. C. , Baker W. R. , Rice P. W.
Published: July 2010

The reduction in plant size of peanuts (Arachis hypogaea L.) by genetic and chemical methods could result in increased productivity with the use of higher plant populations. The effects of increased plant populations on the yield and size of fruit of two Virginia‐type peanut cultivars, ‘NC 17’ and ‘NC 5,’ were investigated in factorial experiments by the use of four interrow and two intrarow spacing treatments and a growth regulator, Kylar. Interrow spacings less than 91.4 cm did not significantly increase the yield and had little effect on fruit size. The cultivars responded differently to Kylar. Seed and fruit size, and yield of NC 17 were reduced by the application of 1.121 kg/ha of Kylar. A similar application of Kylar to NC 5 reduced the fruit size but had no significant effect on yield or sound mature kernels. Both cultivars had higher yields at the 12.7‐cm than at the 25.4‐cm intrarow spacing. Increases in populations of plants reduced in size by genetic or chemical methods does not necessarily lead to an increase in productivity. Present methods of intra‐ and interrow spacings should not be changed for these two cultivars although plant size is reduced for NC 17 and can be reduced chemically for NC 5.
Evaluation of Cottonseed Hydration‐Chilling Treatments for Improving Seedling Emergence
Authors: Wanjura D. F. , Minton E. B.
Published: July 2010

Stands of early season upland cotton (Gossypium hirsutum L.) are often reduced by low soil temperatures. Preplant treatments of acid‐delinted seed, consisting of either single or combined applications of hydrating and chilling, were evaluated for their effect on cottonseed germination and seedling emergence at different temperatures. Problems associated with metering hydrated cottonseed with vacuum and double‐run metering systems were identified. Preplant seed hydration increased germination rate as indicated by early seedling length measurements in germination tests. None of the preplant hydrate or hydrate‐chill treatments increased final germination or emergence compared to dry seed treated with a seed protectant fungicide for the cultivar ‘Paymaster 111.’ Decreased germination resulted from immediately planting seed that were either soaked for 6 hours at 30 C or given the combined treatment of soaking for 6 hours at 30 C and 24 hours at 5 C. Soak or soak‐chill treatments which were allowed to air‐dry 24 hours before planting resulted in increased percentage emergence over seeds planted immediately following soaking. Seed fragments that resulted from the disintegration of seed during rapid hydration decreased seeding rate by clogging the nozzles of the vaccum metering system. Hydrated seed required recalibration of the double‐run mechanical metering system to accommodate the increased seed size.