bluuebunny/crossref_metadata_2025 huggingface dataset:
Gypsum and Elemental Sulfur as Fertilizers on Annual Grassland1
Authors: Jones M. B. , Ruckman J. E.
Published: July 2010

Gypsum and elemental S, each fine enough to pass through a 100‐mesh screen, were applied at equivalent rates in each of 4 years to soils deficient in S. Forage yields, percent clover, total S uptake, and concentration of S in the plants were recorded over a 5‐year period. The two sources of S were equally effective in increasing yield, S uptake and concentration in the forage, and percentage of clover in the stand the first season after application. However, more S from gypsum than from elemental S was taken up during the winter of the first year, while the reverse was true for the following spring. In the second season after treatment, forage production from elemental S approximated that of the first year; however, yields from gypsum were significantly less than in the first year. In subsequent years forage production declined until there was no significant effect from gypsum in the fourth season nor from elemental S in the fifth season. A significant increase in S uptake and percent S in the forage from gypsum was measured the second year; however, with elemental S a significant increase in S uptake persisted through the third year. Percentage clover declined rapidly with each additional year following application with the decline more rapid where gypsum was applied. Efficiency of the S applied varied from 13 to 34%.
Effect of Sawdust on the Germination and Seedling Growth of Several Turfgrasses1
Authors: Waddington D. V. , Lincoln W. C. , Troll J.
Published: July 2010

Studies conducted to determine the effect of sawdust on several turfgrass species indicated that germination and seedling growth may be suppressed by the use of some fresh sawdust materials. Grass was grown in soilsawdust mixtures and germination tests were made using cold water extracts from sawdust. The most severe toxic effects were noted with sawdust from ash and red oak. Abnormal seedlings with stunted roots occurred when seed was germinated in extracts from these materials. Nitrogen fertilization of soil‐sawdust mixtures did not overcome these toxic effects. ‘Merion’ Kentucky bluegrass seems to be more susceptible to the injurious effects than ‘Pennlawn’ creeping red fescue and ‘Highland’ and ‘Seaside’ bentgrasses. The adverse effects were not apparent in sawdust which had weathered for 2 and 7 months.
Factors in Interstrain Variation in Zinc Content of Maize (Zea mays L.) Kernels1
Authors: Massey H. F. , Loeffel Frank A.
Published: July 2010

In 31 inbred lines of maize, which varied widely in Zn concentration of the kernels, the germ (plus embryo), pericarp, and endosperm were found on the average to contain 138, 46, and 9.9 ppm Zn, respectively. The concentration of Zn in each of these kernel components varied widely among the 31 inbreds, however, and the concentration of Zn in the kernel could not be predicted from the relative size of the kernel components. In greenhouse experiments with 32 inbreds, Zn concentration in the kernel was not correlated with Zn uptake by plants or Zn concentration in plants grown on either Zn‐deficient or Zn‐fertilized soil. In field experiments, however, variation among inbred lines in their concentration of Zn in the kernel did appear to be related to the general level of Zn in the plant, but this factor was greatly modified by the extent to which the inbred was able to transfer Zn from the stalk and leaves to the ear. Inbreds Ky211 and Ky209 transferred approximately one‐third of their stalk and leaf Zn to the ear during grain formation. Approximately one‐fourth of the gain in ear Zn from tasseling to maturity by Ky209 × Ky21l could be accounted for by transfer from the stalk and a slight additional amount by transfer from the leaves.
Hydroponics as a Medium for Production of Tree Planting Stock1
Authors: Wilde S. A. , Spyridakis D. E.
Published: July 2010

This paper describes the technique of raising tree planting stock in nutrient solutions and summarizes the results of the field performance of hydroponically produced plants as observed during the past 20 years in Wisconsin. Raising tree seedlings in solutions for a period of from 6 to 12 weeks and the subsequent hardening of trees in nursery beds provided in 1 year planting stock which was fully comparable in size and growth potential to 3‐year‐old (2‐1) transplants. Successful field trials included Alnus glutinosa, Thuja occidentalis, Picea glauca, Picea pungens, and Pinus resinosa; a stand of the latter tree is now 18 years old. Catalpa speciosa showed a remarkably rapid growth upon transplanting to nursery beds, but produced unmanageably bulky root systems.

The success of stock production depended upon suitable adjustment of nutrient solutions, control of their pH values and degree of oxygenation, and occasional pruning of roots. For afforestation of prairie soils, the stock required inoculation with mycorrhizal fungi. Significant advantages of hydroponic cultures are freedom of plants from damage by parasitic organisms and corresponding savings on biocides.

Under present conditions, the possibility of a wider use of tree hydroponics appears to be confined largely to the production of ornamental conifers which exhibit a very slow growth in nursery beds. Hydroponic cultures may also supplement in part the output of forest nurseries, serving largely as an outlet for employment of nursery personnel during the inactive period.
Effect of Population and Row Width on Corn Silage Yields1
Authors: Rutger J. N. , Crowder L. V.
Published: July 2010

Three corn hybrids were evaluated at two locations for 3 years at 50, 88, and 125 thousand plants per hectare in 92‐cm row widths. Two additional row widths, 46 cm and a double row (paired rows 15 cm apart, with 92 cm from the middle of one pair to the middle of the next pair) were employed at the 88,000 planting rate. Maturity was delayed at increasing populations. The amount of dry shelled grain (DSG) in the silage decreased at the higher populations. Total dry matter (TDM) increased about 6% as the population was raised from 50,000 to 88,000 plants. TDM yield at 125,000 plants was the same as at 88,000 plants per hectare. The DSG/TDM ratio decreased as populations were increased. Changing the row width within the 88,000 planting rate had no appreciable effect on the silage characters measured. There was no indication of a hybrid ✕ population (or row width) interaction for any of the characters.
Effect of Paraquat on the Nitrogen Content and Regrowth of Coastal Bermudagrass (Cynodon dactylon (L.) Pers.)
Authors: Agbakoba S. C. O. , Goodin J. R.
Published: July 2010

The nitrogen content and regrowth potential of 'Coastal' bermudagrass (Cynodon dactylon) was investigated following treatment with paraquat. Two rates of fertilizer, 73.7 kg /ha and 1.5 kg/ha, were applied before paraquat application. Five weeks later paraquat was sprayed at the rate of 0.45 kg/ha.

Grass samples were collected at intervals and freezedried, and nitrogen content was determined. Regrowth was evaluated as height and number of new shoots developed from cut stubble of paraquat‐treated plants.

High nitrogen fertilizer applications significantly increased the nitrogen content of Coastal bermudagrass. When these plants were sprayed with paraquat, loss of nitrogen occurred less rapidly than in control plants. Seven weeks following paraquat treatment, the number of shoots produced in regrowth was only about half that of controls. However, there was no difference in the total fresh weight. These results suggest the possibility of using high rates of nitrogen fertilization and the subsequent curing of foliage with paraquat to maintain protein content for an extended period.
Errors in Sampling and Infrared Analysis of CO2 in Air and Their Influence in Determination of Net Photosynthetic Rate1
Authors: Brown K. W. , Rosenberg Norman J.
Published: July 2010

Errors which may arise in sampling and infrared analysis of CO2 concentration in air are discussed. A pressurization technique for calibrating a CO2 analyzer is described. A method for calculating the standard deviation of the rate of photosynthesis based on errors in all measured parameters is presented.
Seasonal Variation in Carbohydrate Root Reserves and Crude Protein and Tannin in Crownvetch Forage, Coronilla varia L.1
Authors: Langille Alan R. , McKee Guy W.
Published: July 2010

Seasonal trends in carbohydrate root reserves of ‘Penngift’ crownvetch (Coronilla varia L.) were similar to those reported for alfalfa but absolute levels approximated those reported for ‘Empire’ birdsfoot trefoil (Lotus corniculatus L.). Date of clipping had little effect on seasonal trends in carbohydrate root reserves other than a transient depression following clipping. Clipping to a 9‐cm height in late summer or early fall did not significantly affect the seasonal pattern of carbohydrate root reserves or lead to winter injury.

The crude protein content of forage of uncut plants of Penngift crownvetch decreased almost linearly from 30% in the spring to 11% in the fall. Growth stage had more influence on protein content of forage than date of clipping, level of root reserves, soil moisture, or soil temperature.

Tannin content of crownvetch forage averaged 1.90% tannic acid equivalent, no higher than that observed for red clover or alfalfa. Tannin content did not vary significantly throughout the growing season or by stage of growth.
Effect of Irrigation on Recovery of Applied Nitrogen by Cotton1
Authors: Doss B. D. , Scarsbrook C. E.
Published: July 2010

Field studies were conducted on a Greenville fine sandy loam to determine the effects of soil moisture regime and N rate on recovery of applied N by cotton. In general, irrigation decreased the percentage of N in plants but tended to increase total N uptake as a result of the increase in dry matter production. Applied N increased both the N percentage and total N uptake of plants, either with or without irrigation.

The slopes of the linear regression equations for nitrogen recovery on nitrogen applied for irrigated cotton were about twice as large as those for unirrigated cotton.

Five years data for both irrigated and unirrigated cotton closely fits the regression equation log Y = 2.333 + 0.727 log X, where Y = dry matter yield and X — N uptake.
Agronomic Characteristics of the Little‐Known, Northern Grass, Arctagrostis latifolia var. arundinacea (Trin.) Griseb., and a Proposed Common Name, Tall Arcticgrass1
Authors: Klebesadel L. J.
Published: July 2010

Arctagrostis latifolia var. arundinacea (Trin.) Griseb. is a tall‐growing, perennial grass confined to global regions above 50° N. Evaluations disclosed that this grass possesses several desirable attributes for possible agronomic use in the Subarctic, including excellent forage yield potential, a high level of winter hardiness, rapid spring growth, and succulent herbage containing markedly less dry‐matter than other grasses compared. A disadvantage is its very small seed size (5,126,000/kg) which contributes to poor seedling vigor and necessitates shallow seed placement, with little associated competition for successful establishment. The common name “tall arcticgrass” is proposed. Several new locations are added to its known range in Alaska.
Peanut Response to Uniform and Non‐uniform Soil Salinity1
Authors: Shalhevet J. , Reiniger P. , Shimshi D.
Published: July 2010

The yield of peanuts (Arachis hypogaea) grown in artificially salinized plots was reduced to 50% at ECe of 4.7 mmhos/cm and by 20% at ECe of 3.8 mmhos/cm. Yield reduction was the same for equal mean soil salinities regardless of the shape of the soil salinity profile. Reduction in water uptake as a result of increased soil salinities was probably the consequence rather than the cause of the reduced growth. The salt tolerance during germination was much higher than during subsequent growth. A 50% reduction in germination was obtained at ECe of 13 mhos/cm and in seedling development at ECe, of 7.2 mmhos/cm.
Frequency and Severity of Defoliation of Crownvetch Stems by Grazing Sheep1
Authors: Hart Richard H.
Published: July 2010

When crownvetch (Coronilla varia L.) was grazed by sheep (21 sheep/ha for 9 days), the probability that a leaf‐bearing stem would be grazed on any day was .134. Over O% of the leaves were removed from nearly all grazed stems, but 21 to 40, 41 to 60, 61 to 80, and 81 to 100% of the leaves were removed from equal numbers of stems. Stem tissue was seldom removed. The pattern of leaf and stem removal under grazing was totally different from the pattern under clipping.
Influence of Row Width and Plant Population on Yield of two Varieties of Corn (Zea mays L.)1
Authors: Brown R. H. , Beaty E. R. , Ethredge W. J. , Hayes D. D.
Published: July 2010

Two varieties of corn (Zea mays L.) were evaluated for grain yield at row widths of 51 and 102 cm and within‐row spacings of 15, 23, 31, 38, and 46 cm. Both varieties, ‘Pioneer 309B’ (P‐309B) and ‘DeKalb XL 65’ (D‐XL 65), were grown with and without irrigation at Plains, Ga., in 1967 and 1968. Pioneer 309B was grown under irrigation at Calhoun, Ga., during the same years. Yields of irrigated corn were higher in 51‐cm than in 102‐cm rows. Without irrigation, P‐309B yielded more grain in 51‐cm than 102‐cm rows, but yields of D‐XL 65 were similar for both row spacings. Increasing populations in the 51‐cm rows from about 50,000 to 100,000 plants/ha did not increase yields except in irrigated D‐XL 65. Yield decreased with increased population in the above range for nonirrigated P‐309B. Increased populations within 102 cm rows increased yields except for P‐309B at Calhoun and unirrigated P‐309B at Plains. Optimum populations were estimated from relationships between log grain yield per plant and population. Estimated optimum populations were higher for 51‐cm than for 102‐cm rows, for irrigated than for nonirrigated corn, and for D‐XL 65 than for the P‐309B variety. Estimated optimum population appeared to be related to plant size with smaller plants requiring a higher population for maximum grain yield. Leaf area per plant for D‐XL 65 was only 0.7 of that for P‐309B. This difference in leaf area was also probably related to estimates of optimum population.
Yield and Water Use by Different Populations of Dryland Corn, Grain Sorghum, and Forage Sorghum in the Western Corn Belt1
Authors: Olson Tamlin C.
Published: July 2010

In South Dakota, grain yields of corn grown in 102‐cm rows with 35,000 plants/hectare and in 51‐cm rows with 45,000 and 70,000 plants/hectare, respectively, decreased with increasing population in adverse soil‐water seasons and were approximately constant during the more favorable growing seasons. Grain yields from grain sorghum planted in 102‐cm rows with 175,000 plants/hectare and in 51‐cm rows with 250,000 and 350,000 plants/hectare were the same in adverse years but increased markedly with increasing population during the better growing seasons. Corn, grain sorghum, and forage sorghum all gave increasing total dry‐matter yields with increasing population throughout the range of populations used. Water use was nearly the same for all crops within each year, although grain sorghum grown at the lowest population tended to use slightly less water.
Effect of Storage Length on Seed Germination in Jute (Corchorus spp.)1
Authors: Jain N. K. , Saha J. R.
Published: July 2010

Seeds of five varieties of Corchorus olitorius and of four varieties of Corchorus capsularis, stored for 2 months to 14 years, were tested for germination. Viability of seeds declined with period of storage. Older seeds had less vigor, and sprouted slowly. The coefficient of correlation between vigor rating and germination percentage was +0.82. Seeds of C. capsularis varieties stored better than C. olitorius varieties up to 38 months, but all seeds were dead after 50 months of storage in a laboratory in glassstoppered bottles.

Varieties within each species varied in storage quality. Decline in germination of C. olitorius varieties ranged from 5.0% in JRO 620 to as much as 71.3% in JRO 632 after storage for 38 months. A low viability of the 1960 crop in six of the nine varieties appears to be due to some seasonal conditions during maturation, but not to rainsoaking before harvest.
Effects of Salt Treatments of Cotton Plants (Gossypium hirsutum L.) on Leaf Mesophyll Cell Microstructure
Authors: Gausman H. W. , Baur P. S. , Porterfield M. P. , Cardenas R.
Published: July 2010

Cotton plants (Gosspium hirsutum L.) were grown hydroponically in a controlled environment to study the effect of three salt treatments on the microstructure of leaf mesophyll cells. Sodium chloride was added to a basic nutrient solution in amounts to give low‐, medium‐, and high‐salt treatments.

Leaves of the same chronological age from the fifth true node were used for electron microscopic studies of mesophyll cell microstructure. Electronmicrographs showed many crystalline deposits in leaf mesophyll cells for the low‐ and high‐salt treatments, but not for the medium‐ salt treatment. Heavy deposits of these crystals occurred in the cytoplasm, central vacuole, cell walls, and intercellular spaces. The high‐salt treatment also produced many necrotic mesophyll cells and changes in chloroplast ultrastructure, and more mitochondria than cells from the medium‐ and low‐salt treated leaves.
Comparative Yield and Fertilizer Efficiency of No‐tillage and Conventionally Tilled Corn1
Authors: Moschler W. W. , Shear G. M. , Martens D. C. , Jones G. D. , Wilmouth R. R.
Published: July 2010

Surface application of fertilizer for no‐tillage (Zea mays L.) corn is probably the most convenient method. The relative efficiency of fertilizer applied in this manner has been undetermined, however. Field experiments on three soil types in Virginia suggest that fertilizer efficiency for no‐tillage corn with surface application was higher than for conventionally tilled corn with an equal disked‐in application. No‐tillage resulted in a 9‐year average yield increase of 25.6% on Lodi silt loam, a 6‐year average increase of 13.7% on Davidson clay loam, and a 5‐year average increase of 39.0% on Cecil clay loam. In addition to increased yields, larger amounts of residual N, P, and K, as well as organic matter, were found in no‐tillage soil in several cases.
Influence of Nitrogen, Phosphorus, and Plant Population on Yield and Quality of Forage Corn1
Authors: Robinson D. L. , Murphy L. S.
Published: July 2010

The acreage of forage corn (Zea mays L.) produced in Kansas has steadily increased to meet the demand for corn silage required by commercial feedlots, Fertilization practices and plant populations are major factors involved in corn production, but their combined effects on yield and quality of forage have not been thoroughly evaluated. Therefore, irrigated forage corn was grown at five plant populations and five levels each of N and P at five field locations in central Kansas during a 3‐year period to determine the influence of each variable on yield and quality of forage produced. An incomplete factorial arrangement of 23 treatments was used in a randomized complete block design. Multiple regression analyses indicated both forage and grain yields were significantly affected by N but not by P or plant population treatments. Treatment variables contributed little to variability in forage quality as measured by in vitro fermentation and forage fiber analyses. Nitrogen, cellulose, and lignin concentrations in the forage contributed up to 84% of the variation in in vitro dry matter digestibility (IVDMD). Simple correlation coefficients indicated a significant negative relationship between N and cellulose concentrations, a significant positive relationship between cellulose and lignin concentrations, and no consistent relationship between lignin and N concentrations in the forage. These results indicate that in central Kansas, irrigated corn yields are primarily a function of the rate of N application, and that a rather wide range of plant populations can be tolerated without significantly affecting yield or quality of forage produced.
Winter Turf Development on Dormant Bermudagrass as Influenced by Summer Cultivation and Winter N Fertilization1
Authors: Schmidt R. E. , Shoulders J. F.
Published: July 2010

Overseeded winter turf on dormant bermudagrass is an important practice in providing live turf for a large portion of the year. It has been observed that as vigorous bermudagrass becomes older satisfactory winter turf is more difficult to establish and maintain. Previous research has shown that cultivation of bermudagrass immediately prior to overseeding cool season turfgrasses has improved winter turf. However, no work has been reported showing the effects of bermudagrass summer cultivation on overseeded winter turf quality. This investigation was initiated to study the relationship of thatch removal in the summer on winter turf quality.

Thatch was removed from a 5‐year‐old putting green with a vertical mower in early, middle, and late summer and soil top dressing was applied after each aeration. N fertilizer was applied in summer, fall, and winter; P and K were maintained at high levels and the pH at 6.5. Ryegrass and red fescue were overseeded after turf mowing in October. The percent ground cover was measured in December, March, May, and June.

The removal of thatch by frequent summer aeration and soil topdressing (cultivation) improved the winter quality of overseeded cool season turf. Excessive nitrogen fertilization in winter, especially on heavily thatched areas, reduced winter turf coverage.

The best transition from cool season turf to bermudagrass occurred when the cool season grass persisted into the summer. The increased Poa annua infestation caused by early cultivation was reduced by more frequent cultivation.
Distinguishing Annual From Perennial Ryegrass1
Authors: Nittler L. W. , Kenny T. J.
Published: July 2010

Since the fluorescence test for distinguishing seeds of Italian ryegrass (Lolium multiflorum Lam.) from those of perennial ryegrass, (Lolium perenne L.) is not always reliable, there is a need for a new method of distinguishing these species. This study was undertaken to determine temperature and nutritional requirements for rapid development of species differences.

Seeds were planted in sand and plants were grown with continuous light and with a temperature of 24 C or with alternating temperature of 27 C for 20 hours and 16 C for 4 hours. Nutrient solutions were made by adding 3.8, 7.5, or 15.0 ml of molar ammonium nitrate per liter of a solution lacking N. One treatment used the lowest N solution the entire experiment. Others used this solution the first 6, 8, 10, or 15 days and then medium or high N solution until 3 weeks after the seeds were planted.

No plants grown from perennial ryegrass seed produced stems or heads. In contrast, up to 70% of Italian ryegrass seedlings had stems and up to 10% were headed out. Stem development and heading were not affected significantly by nutrient treatment. Alternating temperature resulted in significantly (1% level) more plants with stems or heads than constant 24 C. Italian ryegrass plants that had not developed stems could be identified by the fact that they had rolled leaf buds. In contrast, perennial ryegrass seedlings had folded leaf buds.

Growing seedlings with alternating temperature and any of the nutrient treatments used in our experiments appears to be a practical method of distinguishing these species.
An Electronic Sensor and Circuit for Automatic Operation of Rainfall Shelters1
Authors: White C. M. , Myhre D. L. , Williams S. G.
Published: July 2010

A simple, inexpensive, and durable electronic sensor for automatic operation of rainfall shelters for research plots is described. The advantages of the new circuit are: (i) the very high input resistance overcomes problems associated with low conductivity of rainfall; (ii) the limited amount of current through the grid reduces corrosion; and (iii) the time delay prevents reversing of the shelters while in motion. Provision for heating the sensor grid prevents condensation of dew and hastens evaporation on cloudy days after rain stops.
Salt Tolerance of Chickpea Varieties during Germination1
Authors: Kheradnam M. , Ghorashy S. R.
Published: July 2010

Chickpea (Cicer arietinum L.) is grown extensively in Iran. The accumulation of salts in irrigated soils may reduce the germination, growth, and eventually the yield of this crop. Knowledge of variation in salt tolerance in chickpeas is important for assigning varieties to fit the soil.

Effects of seven salinity levels (O to 2% NaCl) on germination of Iranian chickpea varieties, ‘Isfahan 11,’ ‘Ardebill 169,’ ‘Ardebill 174,’ and Ahar 174' were determined under controlled temperature (30 ± 2 C). Increased salinity reduced the germination of Isfahan 11 significantly more than Ardebill 174 and Ahar 174. Sodium chloride concentrations greater than 0.5% reduced the germination of all varieties significantly. The general trend in germination reduction with increased salinity was the same for each variety.
Pima Cotton Lint Yield as Influenced by Irrigation Schedule, Cultivar and Altitude1
Authors: Kittock D. L.
Published: July 2010

Development of heat tolerant cultivars of American Pima cotton (Gossypium barbadense L.) made it desirable to re‐evaluate irrigation practices for hot climates. To accomplish this, two cultivars and one experimental strain were tested over a period of 6 years at two altitudes (climates) and under several irrigation regimes. There were three basic irrigation regimes and several modifications of them. The regimes were: wet, irrigate every 7 to 12 days; medium, 14 to 17 days; and dry, 21 to 28 days. Individual irrigations were added in amounts necessary to refill the soil profile.

At high altitude (moderate climate), the heat tolerant cultivar, ‘Pima S‐4’, did not differ in water requirement from the non‐heat tolerant cultivar, ‘Pima S‐3.’ Both cultivars obtained maximum lint production with a total of 80 cm of water or five post‐emergence irrigations.

At low altitude (hot climate), Pima S‐4 yielded higher and required more water (150 cm) than Pima S‐3 (115 cm). More frequent irrigations during May and June than are commonly applied were indicated for low altitude. Fewer irrigations than commonly used on Pima cotton during August and September (28 days between irrigations) did not decrease yields and, in some cases, significantly increased yields of all cultivars at low altitude.

Consumptive water use for Pima cotton (103 cm) was similar to that previously reported for Upland cotton (105 cm) when grown under similar irrigation regimes.
Light Fluctuations in Corn1
Authors: Desjardins R. L. , Sinclair T. R. , Lemon E. R.
Published: July 2010

The fluctuations of photosynthetically active radiation within different corn (Zea mays L.) varieties were studied in the frequency domain using spectral analysis. This approach which uses a single traversing sensor, provides a simple method for separating the temporal and spatial light fluctuations in a crop. It was found that the light spectra are influenced by the height of the light sensors within crop structure and by wind conditions. The most rapid fluctuations observed were about 10 cycles/second, which tends to discount their importance in the dark reaction of photosynthesis. Finally, these results give a better perspective on fluctuating light experiments.
Factors Affecting Early Growth of Cotton and Subsequent Effects on Plant Development1
Authors: Ashley D. A. , Elsner J. E. , Brooks O. L. , Perry C. E.
Published: July 2010

Seedling cotton (Gossypium hirsutum L.) growth rate is frequently retarded due to adverse environmental conditions and the effects are often reflected in retarded development and performance later in the season. In efforts to find ways of enhancing the ability of the seedling to grow under adverse conditions, cotton plants were grown under field conditions with black plastic mulch, NaNO3, NH4NO3, and (NH4)2SO4 sources of N, and irrigation treatments. Vegetative development, nitrogen uptake, and fruiting behavior were measured in early stages of growth and final yields taken at maturity. Ammonium sources of N resulted in enhanced seedling vigor, plant height, rate of early‐season dry weight accumulation, and rate of early flowering compared to nitrate N sources. A complete ground cover of black plastic mulch gave an additional increase in the early‐season growth and fruiting parameters above that obtained from ammonium N alone. Nitrogen concentration in the tissue in early season did not differ among the treatments; therefore, total N uptake followed closely the response in dry weight accumulation. Yield of cotton was not materially affected by source of N. In general yields were higher from plots receiving NH4NO3 plus plastic mulch than from plots treated with NaNO3 and no plastic mulch.
Response of Phalaris Genotypes and Other Cool‐Season Grasses to Temperature1
Authors: Hoveland C. S. , Foutch H. W. , Buchanan G. A.
Published: July 2010

Improved winter forage production is a major objective in breeding phalaris (Phalaris tuberosa L.) varieties for the southeastern United States. The purpose of our study was to determine morphological and physiological parameters accounting for winter forage productivity. Winter‐productive phalaris genotypes in field and growth chamber experiments responded rapidly to increasing temperatures with more rapid appearance of new leaves and greater leaf expansion rates than tall fescue (Festuca arundinacea Schreb.), reed canarygrass (Phalaris arundinacea L.), orchardgrass (Dactylis glomerata L.), or winter‐dormant phalaris types. Tiller numbers were not related to winter productivity. Fructosans comprised a higher percentage of total nonstructural carbohydrates in winter‐productive than in less winter‐productive phalaris genotypes. Phalaris genotypes did not differ in photosynthetic rates per unit area of leaf surface at several temperatures. Winter‐productivity of certain phalaris genotypes appears to result from rapid development of new leaves and rapid leaf expansion during short periods of favorable temperature, possibly aided by a supply of readily translocated carbohydrates.
Effect of Potassium on the Incidence of Diaporthe sojae in Soybean1
Authors: Crittenden H. W. , Svec L. V.
Published: July 2010

Many varieties of soybean (Glycine max (L.) Merrill) are highly susceptible to the fungus Diaporthe sojae Lehman when grown in Delaware. It has been shown, in Iowa, that potassium levels in upper pods of soybean plants decreased markedly in late season. Because the upper pods frequently had the highest incidence of D. sojae in Delaware and the infection occurs in late season, the relationship of K in soybean to the incidence of disease caused by D. sojae was studied.

Two varieties of soybeans were grown in aluminum lined cylinders on soil testing low in K during the summer of 1972 in the field. This allowed control over the soil volume which the plants could use for a source of K. Potassium chloride and potassium sulfate were added to the soil at O, 2, 10, and 30 g/cylinder. The 30‐g treatment received a 10‐g fertilizer sidedress at midseason. These rates were equivalent to O, 98, 490, and 1,960 kg/ha of K as KC1 and O, 82, 410, and 1,640 kg/ha of K as K2SO4, respectively, which included rates higher than usually used in soybean production. Mature seed was evaluated for incidence of D. sojae.

Significantly less diseased seed occurred as K level increased, although neither KC1 nor K2SO4 prevented incidence of the disease. The K had no significant effect on the seed yield or number of seeds per plant.
Chemical Composition of Three Legume and Four Grass Herbages Harvested at Early Flower during Three Years1
Authors: Smith Dale , Rohweder D. A. , Jorgensen N. A.
Published: July 2010

Three legume and four grass species were grown in pure‐row stands under the same soil conditions, but without N fertilization, and were harvested when each species reached first flower during 3 years. Knowledge of the compositional differences among grasses and legumes is needed to provide additional information for recommending forage species to livestock producers. The dry herbages were analyzed for concentration of in vitro digestible dry matter (IVDDM), total nonstructural carbohydrates (TNC), crude protein, ether extract, crude fiber, ash, K, Ca, Mg, Na, S, Al, Fe, Sr, B, Cu, Zn, and Mn. Red clover (Trifolium pratense L.) was significantly higher than either alfalfa (Medicago sativa L.) or sainfoin (Onobrychis sativa Lam.) in concentration of IVDDM, ether extract, Mg, and Cu. Alfalfa was higher than the other legumes in crude fiber and Na; sainfoin was highest in P. Reed canarygrass (Phalaris arundinacea L.) was significantly higher than bromegrass (Bromus inermis Leyss.), timothy (Phleum pratense L.), and orchardgrass (Dactylis glomerata L.) in concentration of crude protein, was higher than all but orchardgrass in ash and P, and was higher than bromegrass in IVDDM. Orchardgrass was higher than the other grasses in Mn; bromegrass was highest in Cu. There was no significant difference among species for TNC percentage. An average of the analyses showed that the legumes were higher than the grasses in all constituents except crude fiber, ash, K, and Mn.
Corn Hybrid Yield Effects on Phosphorus, Manganese, and Zinc Absorption1
Authors: Terman G. L. , Giordano P. M. , Christensen N. W.
Published: July 2010

Researchers have concluded in several published papers that differences in nutrient absorption among crop cultivars are genetically controlled. However, growth rate and yield differences among cultivars were not usually evaluated. The present investigation involved three greenhouse experiments conducted to study relationships between yield levels and concentrations of P, Mn, and Zn in several corn hybrids (Zea mays L.) during early growth. Eight hybrids were grown with 0, 1, 2, and 4 ppm of Zn in factorial combination with 17 and 167 ppm of P; five hybrids with 0 and 3.4 ppm of Zn and 0, 233, 466, and 932 ppm of P; and three hybrids with 0, 11, 33, 90, 180, and 360 ppm of P. Other nutrients were applied uniformly. Top growth was harvested after 6 to 11 weeks, dried, and analyzed for total P, Mn, and Zn.

Results from these experiments, together with published data, show that concentrations of P, Mn, and Zn among hybrids at each application rate decreased markedly with increasing yields. Higher yields resulting from more rapid growth following a 2‐week delay in planting one hybrid also greatly reduced P concentrations in the plants. Thus, nutrient concentrations and uptake in various corn hybrids, at least during early growth, need to be evaluated in terms of growth rates, total dry matter or final grain yields, and planting and maturity dates. Differences in nutrient absorption among corn hybrids appear to be greatly influenced through genetic effects on growth rates and yield potentials. Plots of yields vs. nutrient concentrations or uptake are useful to determine differences among hybrids at the same yield levels.
Forage Breeding Guidelines for the Potential Economic Benefits of Improving Yield and Quality1
Authors: Shenk J. S.
Published: July 2010

Forage breeders need a method for predicting the potential economic benefits of animal production from experimental strains or breeder lines, based on yield and quality determinations early in the breeding program. Benefits must be expressed in terms of increased animal response (i.e. dairy cow milk production).

An apropriate mathematical model was developed to simulate the plant‐animal response factors, in which maximum milk production was to be achieved from rations of forage supplemented with corn (Zea mays L.) and soybean [Glycine max. (L.) Merr.] oil meal.

The model showed that if either net energy were improved by 0.1 Mcal/kg, protein increased by 4.3%, or yield by 0.79 metric tons of dry matter (DM)/ha, a $43/ha return may be achieved above a standard cultivar yielding 9.9 metric tons DM/ha, with a net energy value of 1.35 Mcal/kg and 16.0% protein. If net energy, protein, and yield were improved simultaneously, the results were largely additive. The model was applied to actual yield and quality data obtained for 10 experimental orchardgrass (Dactylis glomerata L.) synthetics to demonstrate the practicality of this approach. The implications of possible changes in the assumptions used to derive this model are discussed.
Growth and Yield of Safflower in Three Temperature Regimes1
Authors: Abel G. H.
Published: July 2010

A better understanding of the response of safflower (Carthamus tinctorius L.) to elevation, temperature, and date of planting is needed to best exploit this crop in regions of its present adaptation. The objectives of this study were to describe the response of growth characteristics to date of planting when grown in irrigated desert environments that varied in elevation and, therefore, in temperature. Growth characteristics measured during early plant development were days to emergence, days in rosette, and days to flower. For later growth, numbers of branches and heads per plant, seeds per head, seed weight, seed yield, oil percentage of seed, and oil yield were recorded.

Early plantings (November 15 to December 15) in areas of higher elevations provide for lower temperature regimes during growth. The rosette period is lengthened and increased yield of seed and oil occur from increases in head numbers and seeds per head. For November 15 plantings in warm areas of low elevations, temperatures are generally not low enough during early growth for normal plant development and seed production. Later plantings (December 15 to January 15) are recommended for these temperature regimes, however, yield will not be as high as those from colder regimes. Heat‐tolerant germplasm is needed to improve yield of seed and oil percentage of seed for the warmer desert areas of the Southwest.
Response of an Early‐maturing Corn Hybrid to Planting Date and Population in the Northern Plains1
Authors: Alessi J. , Power J. F.
Published: July 2010

With the development of extremely early‐maturing corn (Zea mays L.) cultivars, producers question how late planting can be delayed in semiarid regions without adversely affecting yields and what adjustments in plant populations are necessary. The present study was planned to acquire further information on yield potential of a short season hybrid corn at various planting dates and plant populations. At Mandan, N.D., a 68‐day maturing hybrid was grown at 20,000, 30,000, 40,000 and 60,000 plants/ha in 100‐cm row spacing for 2 years. Average planting dates were May 17 and June 7 and 28. In 1971 and 1972 (years of below normal rainfall), both planting date and plant population significantly affected grain yields. Delaying corn planting to June 7 and 28 reduced grain yield by 10 and 30%, respectively, compared to the May 17 planting. Optimum plant population was 30,000 plants/ha for both dry matter (forage) and grain yields regardless of planting date. Dry matter and grain yields averaged 5,180, 5,120, and 5,280 kg/ha, and 2,120, 1,930, and 1,500 kg/ha for May 17 and June 7 and 28 plantings, respectively. Ear water content increased at both the later dates of planting and at higher populations. Soil water withdrawal by corn was generally confined to the upper 90‐cm depth of soil for all planting dates. Water use efficiency for dry matter production was highest for the June 28 and least for the May 17 plantings. Wateruse efficiency for grain was usually similar for a given population at all planting dates.

Results from this study indicate that an early maturing corn may be planted before mid‐June without greatly reducing dry matter and grain yields in the northern Great Plains.
Effects of Irrigation Regimes, Planting Dates, Nitrogen Levels, and Row Spacing on Safflower Cultivars1
Authors: Abel G. H.
Published: July 2010

Information was needed on application time and amount of irrigation water, date of planting, row spacing, and nitrogen fertilizer rates on cultivars of safflower (Carthamus tinctarius L.). The objective was to develop a more efficient management of the crop. The environments of growth listed above were studied in three experiments over a 3‐year period. In each experiment date of planting was the large plot with irrigation treatments in border‐diked basins as split plots followed by other environnients in the basins as subplots.

In 2 of the 3 years, seed yields were higher in the crop planted 15 December than in that planted 15 February; results were the opposite in the first year because of rank growth due to lower‐than‐average temperatures. An irrigation regime that specified an earlier cutoff date than that for the normal regime saved water and labor, reduced weed growth, and produced optimum seed yields at lower levels of nitrogen fertilization. Other irrigation treatments that limited the amount of water below that of the normal regime (102 to 120 cm), either gave equivocal results or significantly reduced yields. Oil percentage of seed was not affected by irrigation regimes. Plants in two‐row plots produced fewer seeds∕head and smaller seeds than those in one‐row plots. The increased plant populations in the two‐row compensated for these deficiencies and yields were no different.

The optimum level of N fertilization ranged from 84 to 336 kg/ha, depending on date of planting, irrigation regime, and cultivar. For a Laveen clay loam soil (coarseloamy, mixed, hyperthermic, Typic Calciorthid), 168 kg/ha of N was apparently optimum when the crop was planted in December. More than 84 kg/ha, however, produced no yield advantage when the crop was planted two months later. The cultivar ‘Dart’ outyielded ‘Rio’ and ‘Prio’ in 1969, ‘12289’ and ‘US 10’ in 1970, and ‘14154–30’ and ‘PI 209,285’ in 1972. Differences in days to flower and duration of flowering were significantly correlated with seed yield, but the correlations were low. Neither flowering time nor duration affected oil content of the seed.
Effect of Cropping History on Soybean Growth and Nodulation and Soil Rhizobia1
Authors: Elkins D. M. , Hamilton G. , Chan C. K. Y. , Briskovich M. A. , Vandeventer J. W.
Published: July 2010

Published results of Rhizobium research studies are often conflicting and inconclusive as to whether soybean [Glycine max (L.) Merr.] inoculation is beneficial in soils previously cropped to soybeans. Greenhouse studies were conducted to clarify the effect of previous soybean cropping histories (soybeans grown 0 to 11 years previously or never) on soybean nodulation and growth responses and Rhizobium japonicum serogroups and population in southern Illinois soils. Sterile soybean seeds were inoculated with the supernatant from soil suspensions representing different soybean cropping frequencies and variable years since the last soybean crop. Seeds were planted in pots of sterilized sand in the greenhouse and soybean growth, nodulation, and nodule mass or dry weight were evaluated. Dominant nodule serogroup determinations were made on selected treatments. Relative N2 fixation was estimated by means of an acetylene‐reduction assay (ethylene production) and MPN determinations were made on cropping history samples in one experiment.

Correlations were not significant between soybean cropping frequency and nodule number, nodule mass, or ethylene production with but one exception. In most instances, the soybean cropping history of the soils used to inoculate seed did not influence soybean top or root growth if soybeans had ever been grown on a field. No aspect of soybean cropping history significantly influenced the predominant serogroups present in soybean nodules.

These results indicate that under the conditions of these experiments sufficient populations of Rhizobium japonicum persist in southern Illinois soils for at least 10 or 11 years, resulting in good soybean nodulation and growth. Based on these studies, the recommendation of inoculating soybean seed before planting for “inexpensive insurance” regardless of soybean cropping history is questionable.
Seedling Vigor of Some Important Range Species as Affected by Nitrogen and Phosphorus1
Authors: Whalley R. D. B. , McKell C. M.
Published: July 2010

Russian wildrye (Elymus junceus Fisch.) is a valuable species for range seeding throughout the Northern Great Plains and Intermountain region. However, it has poor seedling vigor and establishment is often difficult. This study was designated to investigate the effects of added P and N on the seedling vigor of several species and strains of Elymus in comparison with crested wheatgrass (Agropyron desertorum [Fisch.] Schutt.) and two common competing weeds (cheatgrass, Bromus tectorum L., and Russian thistle, Salsola kali L.). Two factorial experiments were conducted in a greenhouse study involving seven grass species and strains and one forb. Plants were grown at two levels of N and two levels of P which were added to desert soil taken from the 0 to 8 cm and 8 to 30 cm profile depth. Leaf elongation was measured daily for 24 days after emergence. Tillers and leaf numbers were recorded. Harvest weights of leaves and roots were obtained after 49 days. The response of Russian wildrye to added P was detected about 6 days after the emergence of the first leaf, but no response to N was evident until about 15 days. The response to P was of a much greater magnitude than the response to N, and the weeds gave a greater and earlier response to both nutrients. The results suggest that P fertilization of autumn sowings of Russian wildrye could improve its seedling vigor in the field. The variability in response to added P among the species and strains of Elymus suggest that increased seedling response to P might be a useful objective in plant breeding programs aimed at increasing the seedling vigor of this important range species.
Yield and Chemical Composition of Alfalfa as Influenced by High Rates of K Topdressed as KC1 and K2SO41
Authors: Rominger R. S. , Smith Dale , Peterson L. A.
Published: July 2010

Alfalfa (Medicago sativa L.) uses large amounts of soil K. The usual K source for fertilizing alfalfa is KCl. The purpose of the current study was to determine whether Cl and SO4 ions can injure alfalfa when high rates of KCl and K2SO4 are applied. A field stand of ‘Vernal’ alfalfa growing on low fertility Miami silt loam soil (Typic Hapludalf fine‐loamy mixed, mesic) was topdressed for 2 years with 0, 448, 896, 1,344, and 1,792 kg K/ha/year as either KCl or K2SO4. Four harvests were taken in 1972 and in 1973, and one in spring of 1974. Highest 2‐year total herbage yield occurred in KCl‐fertilized plots where 448 kg K/ha/year were applied; yields decreased significantly at rates higher than 896 kg K/ha/year. High yields were obtained at all rates of K2SO4. Highest K concentrations for both KCl and K2SO4‐fertilized herbage occurred where 1,792 kg K/ha/year were applied in 1972 (3.70 and 3.77%, respectively) and in 1973 (3.04 and 3.41%, respectively). Chlorine concentrations in herbage fertilized with KCl ranged from 1.50 to 2.21% in 1972 and 0.82 to 1.15% in 1973. Chlorine concentrations in K2SO4‐fertilized herbage were lower than in KCl‐fertilized herbage; less than 0.77% in 1972 and 0.42% in 1973. Sulfur concentrations in herbage fertilized with K2SO4 ranged from 0.31 to 0.36% in 1972 and from 0.30 to 0.33% in 1973. Where KCl was applied, S concentrations were lower than the control (0.23% in 1972 and 0.26% in 1973). All applications of K lowered N concentrations below the control. It is evident that fertilizer rates higher than 896 kg K/ha/year as KCl can cause significant yield reductions. Therefore, when KCl fertilizer is topdressed at these rates, applications may have to be split among harvests or K2SO4 may have to be substituted for KCl as all or part of the K fertilizer.