bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of Berseem Clover (Trifolium alexandrinum L.) as a Companion Crop1
Authors: Nelson C. J. , Schmid A. R. , Cuykendall C. H.
Published: July 2010

Synopsis

Berseen clover as a spring‐seeded companion crop was erratic in performance. Some seedings gave good forage yields of clover hay with good establishment of underseeded alfalfa, while annual weeds took over in other seedings. Berseem clover performed better in early spring seedings than in late seedings and better at 20 pounds per acre seeding rate than at 10 or 15 pounds per acre. High temperatures appeared to reduce the growth of clover allowing increased growth of annual weeds. Early spring‐seeded clover harvested for hay at the bud stage contained about 15% crude protein.
Effect of Propazine and Atrazine on Ten Hybrid Grain Sorghums, Sorghum vulgare Pers.1
Authors: Phillips W. M. , Ross W. M.
Published: July 2010

Synopsis

Ten grain sorghum hybrids were treated in 1961 and 1962 with 3 pounds per acre propazine preemergence, 3 pounds per acre atrazine postemergence, and cultivation. Each year differences among hybrids were significant, but the hybrid × treatment interaction was not significant. Chemically treated plots significantly outyielded cultivated plots in 1961; they bloomed slightly earlier and were slightly taller in 1962.
Soil Moisture Tension: Presentation for Beginning Soil Students1
Authors: Jacobs H. S. , Withee L. V.
Published: July 2010

Synopsis

A soil moisture tension definition is proposed which can easily be related to the equivalent negative pressure of soil water; capillarity; and soil moisture tension measurements using the tension table, tensiometer, pressure membrane, and centrifuge. Beginning students understand and retain the concept because the definition is simple and because it can be related to many different aspects of soil moisture.
Differences in Rate of Use of Soil Moisture by Stands of Perennial Ryegrass and White Clover1
Authors: Mitchell K. J. , Kerr J. R.
Published: July 2010

Evapotranspiration from tall ryegrass was consistently greater than from short ryegrass and tall or short white clover; the rankings of the latter three treatments varied over the spring periods examined. Although requirements for potential transpiration were met, there were considerable differences in the rates of use of soil moisture between the different pasture stands.
Temperature Influence on Anthesis Date in Grain Sorghum, Sorghum vulgare Pers.1
Authors: Fryer H. C. , Pauli A. W. , Stickler F. C.
Published: July 2010

Day temperatures above 70° F. during the first 30 days after planting and night temperatures below 60° or above 70° hastened maturity. Night temperatures in the 60's retarded maturity. Total degree hours above 70° during the first 20 days were consistently and significantly related to time to half‐bloom. Predictions of time to half‐bloom based on 20 temperature summation variables were not highly reliable.
Effect of Nitrogen Fertilization and Harvest Frequency on Yield and Composition of Panicum maximum Jacq. in Dry Tropics1
Authors: Oakes A. J.
Published: July 2010

The response of applied N and harvest interval on yield and composition of guineagrass was determined. Forage yields increased and protein content decreased with length of harvest interval. Applied N increased yields for all harvest intervals. Applied N was utilized largely in production of dry forage as its protein content was not appreciably increased. Grass harvested at 4‐month intervals receiving 300 pounds of N annually produced nearly 11 tons of dry forage. Protein yields were appreciably increased by N fertilizer, although protein content remained unchanged. Season had a marked effect on yield. Its effects were most pronounced on forage yields when harvested at shorter intervals. Lowered yields, depleted stands, and weed encroachment resulted from grass harvested at 2‐month intervals.
Changes in Content of Total Nitrogen and Organic Matter in Three Nebraska Soils After Seven Years of Cropping Treatments1
Authors: Mazurak Andrew P. , Conard Elverne C.
Published: July 2010

Grasses compared with one another differed in their effect on the change in total N content of Brunizem soil at 0‐ to 6‐inch and 6‐ to 12‐inch depths. However, the mean N content of soil cropped to grasses was not different from the mean for small grains. Plots that received ammonium nitrate fertilizer were significantly higher in total N content of soil in the 0‐ to 6‐inch depth than were the nonfertilized plots.

Grasses growing on Chernozem soil reduced the total N content in the 0‐ to 6‐inch depth of the soil. The application of N fertilizer minimized the losses or increased the total N content of soil.

Application of N fertilizer increased significantly the total N content of the O‐ to 6‐inch depth of Chestnut soil.

Cropping to grain on Chestnut and Chernozem soils necessitates the use of N fertilizer to maintain N content level in the soil. The effect of N fertilizer on the total N content of soil was evident in the 0‐ to 6‐inch depth but not in the 6‐ to 12‐inch depth.

Total oxidizable organic matter content showed the same results as the total N content in soil. Carbon/ nitrogen ratio of the soil was slightly increased during the 7 years of cropping to cool‐season grasses. Warm‐season grasses decreased C/N ratio in Brunizem soil.
Anatomical and Growth Responses of Primary Corn Roots to Several Fertilizers1
Authors: Isensee A. R. , Berger K. C. , Struckmeyer B. Esther
Published: July 2010

The effects of several fertilizer materials on the growth and anatomy of the primary root of corn were studied. The fertilizers consisted of N, P, and K in all possible combinations. They were applied at the rate of 30 pounds per acre on the elemental basis and were placed 1 and 2 inches below the seed.

Roots that contacted the fertilizers exhibited deformities and were shorter than untreated roots, producing an inverse relationship between percent deformity and root length. The most important factor was the fertilizer material. Ammonium nitrate, alone or in other salt combinations, caused the most deformity and shortest roots while P and K alone were least detrimental.

The swollen and deformed root tips from 5 treatments, namely N, P, K, N‐P‐K, and the control were selected for detailed anatomical study. All fertilizer salts caused enlargement and deformity of the root tips compared to the control. Most of the enlargement was the result of abnormal swelling (hypertrophy) of the cortical cells, the intensity of which varied from treatment to treatment. The N‐P‐K and the P fertilizers were most injurious, with the latter causing extensive cellular break‐down and necrosis of the meristematic region.
Herbicide Systems for No‐Tillage Corn (Zea mays L.) Following Sod1
Authors: Triplett G. B.
Published: July 2010

Corn was grown for 3 years following sod, using herbicides rather than tillage to destroy the vegetation. Several herbicide mixtures and rates were used in these experiments to determine materials and rates necessary to destroy vegetation and eliminate growth of weeds from seed present in the soil without injury to the corn plants. Several herbicide systems were satisfactory. Most of these contained atrazine or simazine for control of perennial grasses and annuals and 2,4‐D or similar herbicides for destruction of broadleaf perennials.
Phosphorus Absorption During Various Growth Stages of Spring Wheat and Intermediate Wheatgrass1
Authors: Boatwright G. O. , Viets F. G.
Published: July 2010

Solution cultures were used to study the importance of P absorption during various growth stages of spring wheat and intermediate wheatgrass. Phosphorus was not needed in the solution cultures during all growth phases of the two crops. A supply of P for the first 5 weeks (up to heading for wheat) was adequate to produce maximum dry matter for both species and for maximum grain production of wheat. Maximum root development was achieved when P was supplied for the first 4 weeks of growth.

Although plants absorbed only small quantities of P prior to tillering, this amount was important. When P was withheld for the first 2 weeks, tiller and secondary root development was hindered. Yields of wheat and wheatgrass tops and wheat grain were only 80, 59, and 42% of maximum, respectively.

Although P uptake occurred after wheat headed, this P was not utilized for dry matter or grain production. Maximum accumulation of P occurred when P was initially withheld, but supplied later until harvest.
Tiller and Leaf Behavior of Orchardgrass (Dactylis glomerata L.) in a Broadcast Planting1
Authors: Taylor T. H. , Templeton W. C.
Published: July 2010

The growth and development of a ‘Boone’ orchardgrass sward was observed from sowing in September to 1 year of age. Data were obtained on tiller density, leaf area, dry matter accumulation, rate of leaf appearance and senescence, and carbohydrate food reserves in the stubble.

The young plants tillered profusely in autumn, late winter, and early spring. Tillering in early spring was of first, second, and third order. Under seed‐crop conditions viable tiller density declined from an average of 768 per 10 square decimeters (1.08 square feet) on May 1 to 390 by June 15, the time of seed harvest. At certain times the rate of dry matter accumulation was related to leaf‐area index, but at other periods no relationship was apparent. Individual seedling shoots which flowered in the spring developed 15 leaves during their life cycle. Seedling shoots that failed to flower in spring and remained, viable through the summer continued to add leaves to the short stem axis. An average of 22 leaves per shoot was produced in 1 year. Considering all types of shoots, mean interval between appearance of successive leaves on a plant during the growth periods was 11 days. Life span of leaf blades during spring and summer was 28.0 ± 9.1 days. Stubble of seed‐bearing tillers cut June 15 was higher in carbohydrates than that of contemporary nonflowering tillers. Rapid expansion of leaves on nonflowering tillers accounted for most of the early regrowth following a harvest in which jointing tillers were cut below the meristems.
Effect of Soil Properties on the Persistence of Linuron and Diphenamid in Soils1
Authors: Dubey H. D. , Sigafus Roy E. , Freeman J. F.
Published: July 2010

Initial and residual toxicity of linuron and diphenamid in 11 soils of Kentucky was studied for 17 months under greenhouse conditions, using a bioassay technique. Correlation of ED50 values for these herbicides with the physical and chemical properties of the soils was determined.

Organic matter content showed the highest and most consistent correlation with ED50 values. Exchangeable sodium also showed significant correlation with ED50 but only at certain periods of the study. Amount of clay in the soils was not correlated with ED50 values even though the cation exchange capacity and ED50 were correlated. The kind of clay might have some influence on the results obtained in the study. Organic matter content seemed to play the greatest role in the disappearance of linuron and diphenamid in soils.
Effect of Rice Culture on the Reclamation of Sodic Soils1
Authors: McNeal B. L. , Pearson G. A. , Hatcher J. T. , Bower C. A.
Published: July 2010

Greenhouse and laboratory studies were undertaken to examine the effect of rice culture on the reclamation of sodic soils.

Rice culture hastened the reclamation of coarse‐textured sodic soils, but did not improve the reclamation efficiency per unit of water leached through the soil. The beneficial effects on coarse‐textured soils were traced to a more rapid removal of entrapped air from the larger conducting pores of the soils during rice culture.

After several weeks of rice growth on a mediumtextured soil, the reclamation efficiency per unit of water leached did begin to increase. However, the simultaneous increase in soil hydraulic conductivity suggested that the effect was caused by an increase in the percentage of the cross‐sectional area of the soil that was serviced by conducting pores, rater than by any enhanced solubility of CaCO3 in the presence of CO2 given off by the rice roots.
Principles of Nutrient Uptake from Fertilizer Bands. VII. P32 Uptake by Brace Roots of Maize and Its Distribution Within the Leaves1
Authors: Robertson J. A. , Kang B. T. , Ramirez‐Paz F. , Werkhoven C. H. E. , Ohlrogge A. J.
Published: July 2010

The influence on phosphorus uptake of area of roots in the fertilized soil and the rate of fertilization was investigated using aerial brace roots of maize. Either 1 or 2 brace roots were directed into soil containing 0.62 or 3.10 g of phosphorus labeled with P32. The radioactivity of the tip and/or basal portions of all leaves was measured by wrapping one thickness of leaf around a long G–M tube. The distribution of P32 in several leaves was mapped with an end window G–M tube.

The P32 accumulation measured by the in‐situ technique was highly correlated with that of the standard briquet method. Phosphorus uptake varied with the rate of fertilization and the number of fed brace roots. The proportion of total phosphorus derived from the fertilizer ranged from 1–37%.

The P32 distribution in the leaves depended upon their position relative to the fertilized brace roots. The leaves on the brace root side had higher P32 activity in their tip portions than in their basal portions. This distribution is explained by limited connections between vascular bundles of the stem and the diverging of the leaf veins from the midrib.
Response of Partridge Pea (Cassia fasciculata Michx.) and Korean Lespedeza (Lespedeza stipulacea L.) to Differences in Soil Types, Phosphorus Fertilization, and Plant Populations1
Authors: Foote L. E. , Jackobs J. A.
Published: July 2010

The growth rate and yield of plant parts of partridge pea were compared to those of Korean lespedeza on 5 soil types at 2 levels of phosphorus fertilization and at 4 levels of plant population. Partridge pea seemed to be able to tolerate lower soil phosphorus levels, adverse physical soil conditions, and extremely low and high plant populations with less adverse effect on yield. It was also able to respond more to added phosphorus on the soils with adverse physical conditions and low natural levels of available phosphorus. Korean lespedeza responded more to added phosphorus on the soil which naturally had good physical condition and was naturally fertile. Leaf area, per se, was not a factor.
Physical Soil Amendments, Soil Compaction, Irrigation, and Wetting Agents in Turfgrass Management II. Effects on Top Growth, Salinity, and Minerals in the Tissue1
Authors: Valoras N. , Morgan W. C. , Letey J.
Published: July 2010

Better top growth was observed on soils amended with lignified redwood when the set irrigation program was used. Unamended and lignified redwood amended soils allowed less top growth under tensiometer‐guided irrigation than the peat and calcined clay amended soil. Good growth on lignified redwood which was subjected to considerable leaching was probably caused by the slow continual release of nutrients. Poor growth on the same growth medium when irrigated by tensiometer records was probably caused by high salinity added with the amendment. All of the amendments contributed to the salinity of the resultant soil mix with lignified redwood causing the greatest salinity, peat and calcined clay having less effect. Except for phosphorus, all of the minerals analyzed for in the tops were affected by several of the treatments. Reasons for the differences observed were usually obscure.
Serogroups of Rhizobium japonicum in Soybean Nodules as Affected by Soil Types1
Authors: Damirgi S. M. , Frederick L. R. , Anderson I. C.
Published: July 2010

Employing a rapid agglutination test, serogroups of Rhizobium japonicum were distinguished by using homogenized nodule suspensions as antigens. Most of the nodules obtained from soybeans on Iowa soils were in one of four serogroups: 123, 135, 31, and 3. Serogroup 123 was dominant, averaging 52% in all soils except a few highly alkaline soils dominated by 135. Serogroups 3 and 31 were found in small percentages in many soils. Serogroups 71a, 110, and 117 were rarely found. Generally, variability between soil sites on the same soil type was less than variability between soil types. Serogroup 123 occupied from 79 to 100% of the nodules in 4 soybean fields on Webster, and was present in about 40% of the nodules from Clarion, Winterset, Shelby, and Lagonda soils. In a soil toposequence grading from Clarion (pH 5.9) to Harpster (pH 8.3), 80% of the nodules from Clarion were serogroup 123, but 92% of the nodules from Harpster contained serogroup 135. The predominance of serogroup 123 or 135 seemed related to soil pH. In sterile soil, serotype 123 grew well at pH values from 6.1 to 8.2; in liquid culture, it had a lower pH limit of about 4.0. In sterile soil, growth of serotype 135 appeared best around pH 8.2; in liquid culture, it had a lower pH limit of 5.5. Cropping with soybeans appeared to increase the percentage of 123, but soil type had a greater influence on the distribution of serogroups than did previous cropping history. The factors which affect the dominance of a serogroup in soybean nodules need further evaluation.
Nitrogen Relationships of Three Tropical Forage Legumes in Pure Stands and in Grass Mixtures1
Authors: Whitney A. S. , Kanehiro Y. , Sherman G. D.
Published: July 2010

The capacities of three tropical forage legumes to fix atmospheric N and to transfer fixed N to two associated grasses were evaluated over a 12‐month period under continuously moist climate in Hawaii. Desmodium canum, Centrosema pubescens and D. intortum were grown alone and in combination with napier grass (Pennisetum purpureum) and pangola grass (Digitaria decumbens) in polyethylene‐lined plots filled with fresh volcanic cinders.

The grasses averaged 4,400 pounds DM/acre, and the legumes yielded on the average as follows: D. canum 3,530, C. pubescens 6,720; and D. intortum 16,710 pounds/acre. Forage N yields plus root N levels indicated that N fixation by D. canum averaged less than 85 pounds N/acre, and that no transfer of N from D. canum to either grass occurred. C. pubescens fixed 240 pounds N/acre in pure stand and about 110 pounds N when grown with grasses. Some transfer of N from centro to the grasses was noted during a long (6‐month) growing period, amounting to 6–11% of the N fixed during that period. Intortum fixed 340 pounds N/acre in 12 months, and 5% or less of this was transferred to the associated grasses.

The nitrogen transfer observed apparently involved N released by both the aerial and sub‐aerial portions of the legume plants.
Water Use, Stomatal Action, and Transpiration Unaffected by Atrazine1
Authors: Pallas J. E. , Bertrand A. R.
Published: July 2010

The effects of soil‐applied atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) on water use, stomatal activity, and yield of a hybrid and an open‐pollinated variety of corn were studied in the field. The studies were conducted in Cecil sandy loam soil using two moisture regimes, irrigated and simulated drought (plastic‐covered soil).

Irrigated corn had significantly higher yields, lower water use efficiency, and higher stomatal activity than the nonirrigated corn.

The hybrid yielded more and was a more efficient user of water than the open‐pollinated variety.

Atrazine did not significantly affect yield, water use efficiency, or stomatal activity of corn under the experimental conditions.
Effect of Phosphorus and Nitrogen Placement on Safflower Growth and Phosphorus Absorption
Authors: Werkhoven C. H. E. , Massantini F.
Published: July 2010

The effect of N and P placement on safflower growth and fertilizer P absorption was studied in the greenhouse. One level of N, 112 kg/ha, as NH4NO3, and three levels of P32‐labeled P, viz., 0, 28, and 56 kg P per ha, as Ca(H2PO4)2·H2O, were used. The placements included banding N and P together 2.5 cm below the seed, broadcasting both elements, banding P with the N broadcast, and banding N with the P broadcast. The amount of fertilizer P absorbed and plant heights were measured weekly and the percentages of total plant P and fertilizer‐derived P, as well as the dry matter yield, were determined at the conclusion of the trial. In general, banding of P was more efftcient than broadcasting. Banding 28 kg P per ha was as effective as broadcasting twice that amount. The placement of N was less important than the placement of P. Placement treatments did not affect the total P concentration in the plants.
Germination Characteristics of Cheese‐weed (Malva parviflora L.) Seeds
Authors: Sumner D. C. , Cobb Rodney D.
Published: July 2010

Cheese‐weed (Malva parviflora L.), best known as a weed, has value as a cover crop. The seeds possess mechanisms which delay germination and thus insure establishment over many years. This creates difficulties in testing germination or in establishing crop stands. The seed coat initially is impermeable to water. Permeability alone does not insure germination, which is under additional control, possibly by endogenous inhibiting substances.
Response of Creeping and Noncreeping Alfalfa Clones to Harvesting Regimes1
Authors: Taylor T. H. , Templeton W. C. , Taylor N. L.
Published: July 2010

The behavior of 4 noncreeping and 5 creeping alfalfa clones was observed in a field experiment under 4 harvesting regimes. The 2 clonal types were increased vegetatively and transplanted into Kentucky bluegrass sod. After the establishment year, the plants were harvested 3 and 5 times annually at stubble heights of 2.5 and 12.7 cm (1 and 5 inches) for 2 successive years. Marked variation in yield, creeping, and survival occurred among clones within both clonal types under the 3‐harvest system, whereas little variation was observed among individual clones under the 5‐cut regime, indicating that potential yield, spreading, and survival of a particular genotype may not be expressed unless a compatible harvesting system is imposed. Creeping and noncreeping types responded similarly to harvesting frequencies and height of cutting. The advantage of creeping over noncreeping alfalfa appears to lie primarily in the ability of creeping types to thicken stands under lenient harvesting management.
Soil Factors Influencing the Growth of Cotton Following Peach Orchards1
Authors: Lee C. R. , Page N. R.
Published: July 2010

Cotton grown in pot cultures of Faceville sand (pH 5.3) from a peach orchard site showed stunted growth, leaf chlorosis, and high concentrations of Zn and Mn. Raising soil pH to 6.0 or above with CaCO3 + MgCO3, peach tree ash, or Na2CO3 produced normal growth and decreased concentrations of Zn and Mn in cotton plants. Adding P as Ca(H2PO4)2 or CaSO4 + MgSO4 did not improve growth. The sulfates which lowered soil pH accentuated leaf abnormalities and increased plant content of Zn and Mn.

Lowering pH of Eustis sand, which had never been in peaches, to 5.0 had no effect on growth of cotton. Adding an amount of Zn much below that sprayed on peach trees during the life of an orchard produced stunted growth and chlorotic leaves.

Stunted growth of cotton following peaches appeared to be caused largely by Zn spray residues made available by low soil pH. The trouble was corrected by raising soil pH to 6.0 or above.
Yield, Protein, Nitrate, and Prussic Acid Content of Sudangrass, Sudangrass Hybrids, and Pearl Millets Harvested at Two Cutting Frequencies and Two Stubble Heights1
Authors: Burger A. W. , Hittle C. N.
Published: July 2010

Three sorghum × sudangrass hybrids, one sudangrass hybrid, three pearl millet hybrids, and ‘Piper’ sudangrass were harvested at two stubble heights and two cutting frequencies during the 1964 and 1965 growing seasons. Growth and chemical composition responses were as follows:

Yields of all varieties harvested three times per year were superior to those of varieties harvested four times per year.

Yields of all varieties cut at the 7.6‐cm (3 inch) stubble height were higher than those of varieties cut at 15.2‐cm (6 inch) when they were cut three times per year, excepting PM × 1 and PM × 3 in 1964.

The crude protein of all varieties was 2.6% higher when harvested four compared with three times per year. Crude protein levels were higher when varieties were cut at 7.6‐cm compared with 15.2‐cm stubble height in the 4‐cut system. In the 3‐cut system, only small differences in crude protein resulted from varying the stubble height.

The nitrate nitrogen accumulation in the herbage of all varieties was higher when they were cut at the 7.6‐cm compared with the 15.2‐cm stubble height in the 4‐cut frequency. The nitrate nitrogen content of the herbage of the pearl millet varieties was higher than for Piper sudangrass and/or sudangrass hybrids.

In the 3‐cut frequency, higher HCN levels were found for herbage cut at the 15.2‐cm stubble height, whereas, in the 4‐cut frequency, higher HCN levels resulted from herbage cut at the 7.6‐cm stubble height.

The average HCN level and, with but one exception, the nitrate nitrogen content of the herbage of sorghum × sudangrass hybrids were higher than those for the herbage of Piper sudangrass.
Nitrogen and Sugar Levels of Pith Tissue in Corn as Influenced by Plant Age and by Potassium and Chloride Ion Fertilization1
Authors: Martens J. W. , Arny D. C.
Published: July 2010

Organic nitrogen and sugar levels in the second internode pith tissue of three corn (Zea mays L.) lines, with three fertilizer treatments, were determined over a period of 9 weeks, beginning shortly before silking. Nitrogen levels were highest at 11 weeks after planting, or about silking time, and then declined. Total and reducing sugars in the pith tissue increased up to 13 to 15 weeks and then declined. The application of 168 kg/ha (150 lb/acre) of potassium as KCl significantly increased organic nitrogen levels in two of the three lines under study. Reducing sugars were sharply decreased in all corn lines by the KCl treatment. The application of 157 kg/ha (140 lb/acre) of chloride ion as NH4Cl (without K+) significantly decreased reducing sugar levels in one corn line and, in general, had effects similar to, but smaller than, the KCl treatment.
Salinity Tolerance of Seven Varieties of Creeping Bentgrass, Agrostis palustris Huds.
Authors: Youngner V. B. , Lunt O. R. , Nudge F.
Published: July 2010

Significant differences were observed for salinity tolerance among creeping bentgrass varieties grown in solution cultures. Top growth of all varieties decreased with increased salinity. In terms of relative yields of clippings, ‘Arlington,’ ‘Seaside,’ ‘Pennlu,’ and ‘Old Orchard’ were most tolerant; ‘Congressional’ and ‘Cohansey‘ were intermediate; and ‘Penncross’ was least tolerant. Seaside had the highest survival rating under extreme saline conditions and the best recovery when removed from the salt treatments. Congressional had the lowest survival rating at the high salt levels. There was evidence of variation for salt tolerance among individual plants within the Seaside variety.
Response of Zea mays L. to a “Light Rich” Field Environment1
Authors: Pendleton J. W. , Egli D. B. , Peters D. B.
Published: July 2010

Many past studies with Zea mays L. evaluated the effect of artificial shade or a reduced light environment on corn production. The response of this crop to a “light rich” environment was investigated over a 2‐year period at Urbana, Ill., where other ecological factors were deemed adequate.

Grain yields were greatly increased by growing plants in front of large reflectors. Theoretical yields of 23,710 kg/ha (377 bu/acre) were obtained. Border plants in the “light rich” environment had more tillers, more plants with two ears, shorter stalks with greater diameter, and a slightly larger leaf area than plants from inner rows or normal border rows. These studies suggest that under field conditions all leaves on corn plants are not light saturated, even at low rates of planting, and, therefore, light appears to be the primary ecological factor limiting the grain yield of this crop when grown under highly productive conditions.
Comparison of Momentum and Energy Balance Methods of Computing Vertical Transfer Within a Crop1
Authors: Wright J. L. , Brown K. W.
Published: July 2010

Measurements of windspeed, air temperature, wet‐bulb depression, and net radiation were made at several levels within and above the crop. Soil heat flux and incident radiation were also measured. Transfer coefficient distributions were computed separately from the windspeed data by a momentum balance approach, and from the other data by the energy balance method. The agreement between the two methods was better near the top of the crop than near the soil. Drag coefficients computed from the energy balance results were not independent of height within the crop as was assumed in the momentum balance analysis. The low Reynolds numbers for the lower portion of the crop could account for the deviation. The energy balance approach required more measurements but was easier to apply in calculating the distribution of the transfer coefficient for the computation of the vertical flux of such entities as heat, water vapor, and carbon dioxide within the crop.
Relative Effects of Acid Subsoils on Cotton Yields in Field Experiments and on Cotton Roots in Growth‐Chamber Experiments1
Authors: Adams Fred , Pearson R. W. , Doss B. D.
Published: July 2010

Field experiments were conducted with cotton on Norfolk, Magnolia, and Greenville soils where previous treatments had established different subsoil acidity levels at each test site. The surface soil of each plot was differentially limed wth a very fine lime to adjust its pH within the range of 6.0 to 6.5. Bulk subsoil samples were obtained from representative plots at each subsoil pH level, and the rate of early cotton root growth was measured with short‐term experiments in a controlled environment. Yields in the field experiments were considerably less sensitive to subsoil acidity differences than were cotton roots in the controlled environment. Maximum cotton yields in the field were obtained on soils in which the rate of root growth inthe subsoils during short‐term experiments was only ½ to % of the maximum rate. The data suggest that maximum yields in the field are realized from a root system mat proliferates in the subsoil at a rate considerably below its potential.
Effects of Potassium and Chloride Ion on Root Necrosis, Stalk Rot, and Pith Condition in Corn (Zea mays L.)1
Authors: Martens J. W. , Arny D. C.
Published: July 2010

Potassium chloride, applied at 168 kg/ha (150 lb/acre) potassium, decreased natural root necrosis and delayed death of corn plants, but increased stalk rot when the stalks were inoculated with Diplodia maydis (Berk) Sacc. (Diplodia zeae (Schw.) Lev.). Pith density (number of live cells) increased significantly with KCl treatment in two of the three corn lines under study. Applying 158 kg/ha (140 lb/acre) chloride ion as NH4Cl (without K+) significantly increased pith density in one corn line and in general had effects similar to, but smaller than, the KCl treatment. Extensive pith degeneration had already occurred at silking time, before peak sugar levels in this tissue, in the two lines which are considered most susceptible to stalk rot.
An Evaluation of Asphalt Coatings on Phosphorus Fertilizers1
Authors: Hall J. K. , Baker D. E.
Published: July 2010

Controlling the dissolution rate of P from fertilizer by use of an effective asphalt coating on water‐soluble superphosphate did not result in increased recovery of added P by successive crops. Average growth response of plants and amounts of P absorbed from this coated fertilizer by successive croppings were less than those obtained by plants grown with water‐insoluble dicalcium phosphate and calcium metaphosphate. Four to five times as much of the coated as uncoated superphosphate was required to supply equal amounts of P to millet. With reduced availability of P in the coated fertilizer, a much larger portion of the plant P was absorbed from the indigenous soil P.

The asphalt coating which was effective on superphosphate was not effective on diammonium phosphate or magnesium ammonium phosphate because ot failure to adhere to the surface of the crystals. Other similar asphalt coatings were not effective on superphosphate.
Molybdenum Deficiency of Cauliflower Influenced by Soil Moisture and Fertilizer Rate1
Authors: Allen Lee D. , Laughlin Winston M.
Published: July 2010

Cauliflower plants in an irrigation field trial involving two rates of commercial fertilizer developed a nutritional deficiency where no supplemental water was applied. Rapid recovery following application of a Mo foliar spray enabled a crop to be harvested. Photographs illustrate foliage symptoms and response to Mo foliar spray.
Herbicide versus Cultivation for Corn with Two Methods of Seedbed Preparation
Authors: Hinesly T. D. , Knake E. L. , Seif R. D.
Published: July 2010

A split‐plot experiment consisting of two methods of seedbed preparation for corn with three methods of weed control was conducted on the same areas of seven different soil types during 1962, 1963, and 1964. Conventional tillage (three diskings after plowing) was compared to reduced tillage (one disking after plowing) as a seedbed preparation variable. Weed control methods on subplots consisted of cultivation alone, atrazine alone, and atrazine plus cultivation.
Effects of Spittlebug Injury on Root Production and Sod Reserves of Coastal Bermudagrass1
Authors: Taliaferro C. M. , Byers R. A. , Burton G. W.
Published: July 2010

Aboveground growth in fields of Coastal and other bermudagrass cultivars is often severely injured or killed in the southeastern United States by the two‐lined spittlebug, Prosapia bicincta (Say). Results of greenhouse and field investigations show that sustained spittlebug damage to the aboveground growth of Coastal bermudagrass significantly reduces root production and available sod reserves. The data suggest that the toxin, which the insect injects into plant stems, has little if any adverse effect on underground plant parts and that the reduction in root development and sod reserves is primarily a function of the cessation of photosynthesis and other essential life processes in top growth. The significant reduction in roots and sod reserves indicates that prolonged or yearly repetition of spittlebug damage can be expected to drastically reduce the productivity and persistence of bermudagrass.
Manganese Nutrition of Sweet Potatoes in Relation to Manganese Content, Deficiency Symptoms, and Growth1
Authors: Mishra Upendra N. , Kelley James D.
Published: July 2010

Sweet potatoes, variety ‘Allgold’, were grown in nutrient culture under greenhouse conditions at 8 levels of Mn ranging from 0.002 to 0.25 ppm. Maximum weight of roots and shoots were obtained at an Mn concentration of 0.031 ppm in the nutrient solution. Manganese concentration was higher in the blades than in the petioles and roots. Maximum growth was obtained in plants with an Mn concentration between 25 and 60 ppm in the blades and 20 to 30 ppm in the petioles. Growth of sweet potatoes was more closely related to the Mn concentration of the blades than that of petioles or roots. Initial deficiency symptoms were observed in younger leaves having an Mn concentration of less than 25 ppm in the blades and 18 ppm in the petioles. Manganese nutrition had no significant influence on the K, Ca, and Mg concentrations of the roots, petioles, and blades. Phosphorous concentration of the petioles was influenced by Mn nutrition.
A System for Short Interval Measurement of Evapotranspiration1
Authors: Peck N. H. , Mielke L. N. , Vittum M. T.
Published: July 2010

Plants were grown in sand‐nutrient culture beeds in the field. Nutrient solution was cycled from the sand beds to elevated measuring tanks. Float recorders in the tanks measured the decrease in volume, or evapotranspiration, for each 2‐hour cycle.
EFfect of Sulfur and Trace Minerals on Forage Sorghum Yield and Mineral Composition1
Authors: Owen D. F. , Furr R. D.
Published: July 2010

Peliminary research indicates that forage sorghum hybrids and varieties differ in nitrogen and mineral contents. Contents of N, P, K, S, Ca, Zn, and Mn varied significantly among varieties. The varieties tested were below the postulated optimum beef cattle requirements for P, Ca, S, and Zn. Chelated minerals and sulfur added to the soil before planting did not affect the yield or mineral composition of the varieties tested.
Evapotranspiration of Cotton and Estimation Methods1
Authors: Namken L. N. , Gerard C. J. , Brown R. G.
Published: July 2010

Average measured ET curves and ET/RS curves were developed for estimating short‐period (7 to 14 days) or seasonal ET for cotton grown under wet, moderate, and dry soil moisture regimes on a medium‐ and a fine‐textured soil in the Lower Rio Grande Valley of Texas. Maximum average ET rates ranged from 0.46 cm per day for the dry moisture regime to 0.74 cm per day on the wet moisture regime on the medium‐textured soil compared with 0.46 to 0.76 cm per day on the dry and wet moisture regimes, respectively, on the fine‐textured soil.

Comparison of the two estimating methods indicated that cotton ET estimates made from average ET were as reliable as estimates made from ET/RS and solar radiation.
Evapotranspiration Rates for Irrigated Crops at Geneva, New York1
Authors: Peck N. H. , Vittum M. T. , Gibbs G. H.
Published: July 2010

Evapotranspiration rates for alfalfa and vegetable crops were determined by measuring changes in available soil water, using gypsum blocks placed at depths of 10, 30, and 50 cm. Available soil water was maintained above 50% capacity in the surface 60 cm of soil for the vegetable crops, and for alfalfa after the first cutting was made in June. Each crop was grown in at least 5 years. Maximum daily evapotranspiration rates and the dates that they occurred as calculated from standard quadratic regression equations were: alfalfa, 3.8 mm, July 26; tomatoes, 4.3 mm, July 29; snap beans, 4.3 mm, August 4; cabbage, 4.3 mm, August 16; sweet corn, 4.6 mm, July 31; squash, 4.1 mm, July 31; and peas, 5.3 mm, June 30.
Interaction Effects of Atrazine and CDAA, Linuron, Amiben, or Trifluralin on Soybean Growth1
Authors: Espinoza W. G. , Adams R. S. , Behrens R.
Published: July 2010

Growth chamber experiments were conducted to study the influence of atrazine, CDAA, linuron, amiben, trifluralin, and combinations of atrazine with these herbicides on the dry matter produced by two varieties of soybeans. Sublethal atrazine treatments did not significantly depress soybean growth as compared to the control. The effect of atrazine in combination with CDAA or linuron was not significant. When damping off organisms were not controlled, severe injury to soybeans occurred in treatments containing amiben or trifluralin at 4.5 ppmw. Sublethal amounts of atrazine appeared to overcome this injury. When seeds were treated with fungicide, the growth of soybean seedlings was depressed by treatments containing combinations of trifluralin and atrazine in proportiont to the amount of atrazine present. Combinations of atrazine and amiben gave growth responses similar to those observed in the earlier experiments, except that pathogen injury was inhibited by the fungicide.
Use of Regression Residuals in the Calculation of Orthogonal Polynomial Coefficients1
Authors: Cady F. B. , Fuller W. A.
Published: July 2010

A method is presented for calculating orthogonal polynomial coefficients when the levels of the independent variable are not equally spaced and(or) replicated. The coefficients may be found by using a standard regression computer program or by means of a hand calculator. The method is based on the orthogonality between the computed residuals and the independent variables in a regression analysis.
Interrelationships Among Dry Weight of Panicles, Threshing Percentage and Grain Yield in Sorghum1
Authors: Atkins R. E. , Reich V. H. , Beil G. M. , Kirby J. S.
Published: July 2010

Evaluations of dry panicle weight and threshing percentage in relation to threshed grain weights were made from grain sorghum yield trials conducted at four Iowa locations over a 3‐year period. Correlation coefficients of 0.91 to 1.00 for the association of panicle weight with threshed grain weight indicated that weights from unthreshed panicles may serve as an expedient and effective selection criterion for relative grain yield among a group of hybrids.

Variability exhibited among hybrids, locations and years for grain percentage of the panicle suggested that the use of a standard threshing percentage to estimate actual grain yields from dry weights of unthreshed panicles would not be advisable.

Grain yields estimated for each entry in all tests, using a regression procedure derived from dry panicle weights and a sampling of threshed grain weights, were compared with actual threshed grain weights. Examination of the deviations of estimated from actual yields for nearly 500 comparisons cast considerable doubt on the reliability of the estimation procedure. Ranges obtained between the largest positive and negative deviations among hybrids within each experiment were consistently larger than would be acceptable in most grain sorghum experiments. When precise evaluations for grain yield per se are needed, the separation of grain from the panicles seems a necessary procedure.
Effect of Water Table Depth and Method of Watering on Yield of Stringbeans1
Authors: Williamson R. E.
Published: July 2010

The yield of stringbeans (Phaseolus vulgaris L.) grown in field lysimeters in which water tables were maintained at constant depths was determined for treatments with and without surface watering. The yield was highly dependent upon the method of watering. When both subsurface and surface water applications were made, the yield of pods and vines was almost 0 for the 15.2‐cm water table depth. As the depth to the water table increased, the yield continued to increase until the maximum yield was obtained with water tables at 61 to 76 cm. With only subsurface watering, the yield from the 15.2‐cm water table treatment was about half the maximum yield which was obtained at the 30.5‐cm water table depth.
A Versatile, Bibliographic Punched Card System for Agronomists1
Authors: Siemer E. G. , Wood D. R.
Published: July 2010

A versatile, inexpensive, simply operated punched card system is described. Cards may be sorted according to 1) author, 2) biological organism, 3) two separate topics, 4) two external environmental factors affecting the organism, or 5) article type. The system is readily adaptable to scientists in many research disciplines.
A Model Demonstrating Use of Linear Programming in Determining Optimum Economic Crop Production from Soils Under Different Management Schemes1
Authors: Keefer R. F. , Bennett O. L. , Nesselroad P. E.
Published: July 2010

A model involving use of linear programming to determine optimum returns from different types of management systems which affect crop yields has been proposed. This model has been successfully applied to an example of fertilizer‐yield data obtained on soils of three different fertility levels, and thereby illustrates the importance of agronomists in collecting data of this kind for the agriculturally important soil series. Value of the crop produced along with the capital available can easily be varied to meet the requirements of time and resources of the farmer. Various types of problems which may be solved by this model have been suggested.
Two Beta Sources Compared for Evaluating Water Status of Plants1
Authors: Rolston D. E. , Horton M. L.
Published: July 2010

Two sources of beta radiation, carbon‐14 (C14) and promethium‐147 (Pm147), were investigated for determination of leaf water content of three plant species over a range of water stress conditions. The plant species used were soybean (Glycine max L.), sorghum (Sorghum vulgare L.), and barley (Hordeum vulgare L.). Results obtained with both sources gave high correlations of relative turgidity with attenuated radiation. However, for relative turgidities above 60% in the plants studied, higher correlation coefficients were obtained using the C14 source. Results indicated that the C14 method appeared to be more sensitive to small changes in relative turgidity than was the Pm147 method. Leaf disc sections taken from sorghum and barley leaves gave more uniform response to water stress changes than did whole leaves.
Temperature Control of Soil in Field Plots: Equipment Design1
Authors: MacLeod N. H. , Decker A. M.
Published: July 2010

The mechanical and electrical design of equipment capable of controlling field plot soil temperatures at three treatment levels in the range of 10 to 30 C is described. Data from one growth season indicate a useful separation of controlled soil temperatures.
Performance of Short Stature Grain Sorghum Hybrids at Different Row and Plant Spacings1
Authors: Atkins R. E. , Reich V. H. , Kern J. J.
Published: July 2010

The performance of two short‐stature grain sorghum (Sorghum bicolor (L) Moench) hybrids at two row spacings and four within‐row plant populations was evaluated at Ames, Iowa, in 1965 and 1966. Mean grain yield for both hybrids over all within‐row plant populations showed an 11% advantage for 76‐cm (30‐inch) over 102‐cm (40‐inch) row spacings. A within‐row population of five plants/30‐5 cm (1 foot) produced highest grain yields at each row spacing. With each row spacing, seeds/head and heads/plant decreased progressively as the within‐row plant population increased from four through eight plants/30.5 cm. Days to mid‐bloom, plant height, and 100‐seed weight were not altered appreciably as row spacings and within‐row plant populations were varied. Interactions among the treatments did not identify differential performance patterns of marked practical consequence, and the interactions most often did not meet the tests for significance.
Plant Constituents of an Early and a Late Corn Hybrid as Affected by Row Spacing and Plant Population1
Authors: Bryant H. T. , Blaser R. E.
Published: July 2010

An early and a late maturing hybrid corn (Zea mays L.) grown at different plant populations and row spacings were compared for proportion of ears, stalks, leaves, and husks to whole plant. Populations of 39,500, 49,400, 66,700, and 98,800 plants/ha were studied with each row spacing of 36, 53, 71, and 89 cm. The corn was harvested when the grain was well dented and silage and grain yields were also obtained.

The stalks, leaves, and husks, as determined by hand separations, comprised a larger proportion, and the ears a smaller proportion of the total dry weight of the late than early hybrid. Each year the proportion of stalks to total dry weight of both hybrids was the smallest from rows 53 cm apart. The weight of the total corn plant, averaged for both hybrids at all population levels, decreased slightly with each increase in distance between rows. As plant population increased, the weight of the individual plant constituents, averaged for both hybrids at all rows spacings, decreased proportionally. The average yield of silage was larger but the average yield of grain was smaller from the late than early hybrid. Planting at 98,800 compared with 39,500 plants/ha gave larger silage yields with either hybrid.
Agronomic Factors Affecting Polonium‐210 and Lead‐210 Levels in Tobacco. II. Varieties and Curing Methods
Authors: Tso T. C. , Carr J. M. , Ferri E. S. , Baratta E. J.
Published: July 2010

Tobacco seedlings accumulated Pb210 and Po210 to a concentration much higher than that found in the soil. The levels of these radioelements decreased as the plants grew. Only minor differences were observed in harvested leaves of two flue‐cured varieties — ‘Coker 319’ and ‘Virginia Bright Leaf.’ The Pb210 and Po210 content in the seeds are in much lower levels than those in the respective leaves produced from the same plant. Neither of the two methods of flue‐curing — a closed system with wood or an open system with kerosene — resulted in significant differences in radioisotope levels of cured leaf. Pb210 and Po210, if present in the combustion products of wood, were trapped in or exhausted through the flue pipes and were not deposited on the tobacco. Kerosene, because it contains little radioactivity, would not contribute much to the Pb210 and Po210 level of cured leaf when fully exposed to products of combustion in an open system.