bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of Water Uptake and Root Distribution1
Authors: Molz Fred J.
Published: July 2010

A simplified version of a mathematical model developed by Molz and Remson (1970) is used to compute “effective root distribution” for sorghum. Data from an experiment by Gardner (1964) are utilized in the computation, and the computed root distribution is compared with the measured distribution. The effective distribution is computed for 1, 3, 5, and 7 days after the beginning of the experiment, and results indicate that it is a complex quantity which varies in both space and time. Initially, the two distributions bear little resemblance, but as the soil dries due to transpiration, they become quite similar. The computations lend support to the model of Molz and Remson (1970) and might be interpreted as indicating the existence of significant impedence to moisture flow in the plant roots under moist conditions. Longitudinal variations in root surface permeability and root growth could also contribute to the computed behavior.
Influence of Soil Fe and MnEDTA Interactions upon the Fe and Mn Nutrition of Bean Plants1
Authors: Knezek B. D. , Greinert H.
Published: July 2010

Several combinations of inorganic and chelated (EDTA) Fe and Mn were added to Mn‐deficient Houghton muck. Navy bean (Phaseolus vulgaris L.) growth, nutrient uptake, and Fe:Mn ratios were obtained on two successive crops in the greenhouse. Exchangeable Fe and Mn and easily reducible Mn were determined on the soil after the second crop. Addition of MnEDTA or FeEDTA to the soil intensified visual Mn‐deficiency symptoms, reduced growth, and reduced Mn uptake while the Fe concentration remained relatively constant, resulting in a wide Fe:Mn ratio in plants grown in the presence of EDTA. Soil ammonium acetate‐extractable Mn and Fe values indicated that Fe increased by a factor of 20 in the presence of EDTA, while Mn did not change. The ineffectiveness of MnEDTA in overcoming plant Mn deficiency was due to a rapid substitution of Fe for Mn in the EDTA molecule with probable inactivation of the released Mn by complexing with organic matter. Hence, the aggravation of an already critical Fe:Mn ratio in the soil was accomplished, less Mn was taken up by plants, and Mn deficiency was intensified with the use of MnEDTA.
Nitrogen and Sulfur Nutrition of Sweet Corn in Relation to Fertilization and Water Composition1
Authors: Daigger L. A. , Fox R. L.
Published: July 2010

The external and internal S and N requirements of field‐grown sweet corn (Zea mays) were investigated. The experimental soil was a Bridgeport fine sandy loam of western Nebraska. It contained 4 ppm extractable sulfate‐S. Irrigation water contained 3 ppm S. Nitrification rate was 14 ppm during 10 days at 25 C. Five N levels (45, 90, 135, 180, and 225 kg/ha as NH4NO3) and 3 S levels (0, 22, and 666 kg/ha as gypsum) were arranged factorial combination, randomized block with five replications. Increases in yield from S fertilization were observed at low rates of applied N. Critical levels of S and N in the ear leaf were about 0.24% and 2.9% respectively. Yields were closely associated with N percentage of the ear leaf and N percentage of the ear leaf was increased by both N and S fertilization. When no S was added, 225 kg N/ha was required for maximum yield (13.5 tons), but when 66 kg S/ha was applied, yield was maximum (13.4 tons) at 135 kg N/ha. A case for the usefulness N:S ratios could not be made from the data examined. Sampling at silking stage is probably too late for effective foliar diagnosis of S deficiency in corn. The probability that S was borderline deficient under these conditions suggests that the external requirement for SOM4‐S in the soil solution is about 3 ppm.
Effect of Night Air Temperature on Grain Yield of Corn, Wheat, and Soybeans1
Authors: Peters D. B. , Pendleton J. W. , Hageman R. H. , Brown C. M.
Published: July 2010

In an unreplicated test, high air temperatures at night reduced corn (Zea mays L.) yield about 40%, wheat (Triticum aestivum L.) yield almost 50%, and soybean (Glycine max L. Merr.) yield about 10% as compared with yields of crops growing at cool night temperatures.
Energy Balance and Water Use of Rice Grown in the Central Valley of California1
Authors: Lourence F. J. , Pruitt W. O.
Published: July 2010

Very little basic work has been done within the USA on the energy balance of a rice crop (Oryza sativa L.) as affected by surface and climatic conditions.

During 1968 and 1969, energy‐balance studies were conducted in the middle of a very large rice field 40.2 km (25 mi) north of Davis, California. Evapotranspiration data obtained were compared with data from a large weighing lysimeter at Davis, planted to grass. From daily ratios thus obtained, estimates of normal monthly evapotranspiration for rice were obtained, using data from the long‐term lysimeter study at Davis. For a May 1 to October 1 period, a normal seasonal use for rice of 920 mm (36.2 in) was indicated, a value only 3.5% greater than the 10‐year mean of 889 mm of water used by fescue (Festuca eliator L.) at Davis during the same period.

Air temperature differences between the rice site and the Davis lysimeter were rather minor, but humidities were markedly higher over the rice. Lower wind speed at the rice site, no doubt, contributed to the higher humidity, although the very extensive up‐wind fetch of rice (2 km or greater) was probably a more important factor. The much higher humidities and somewhat lower wind speeds at the rice site are believed to have reduced the evaporation potential by as much as 20 to 25% below that at Davis. Although in this study evapotranspiration by rice and by grass was very similar, it is estimated that losses by rice, in a plot similar in size to the grass plot, would have exceeded the loss by grass by as much as 20 to 25% if the two crops had been grown at Davis.
Yield and Quality Response of Burley Tobacco to Nitrogen and Potassium1
Authors: Colyer Dale , Pohlman G. Gordon
Published: July 2010

Experiments by the Ohio Valley Experiment Station at Point Pleasant, West Virginia were conducted over an eight‐year period to test for response to nitrogen and potassium fertilizer by burley tobacco (Nicotiana tabacum L.). Both yield and quality were affected by the level of fertilizer use, with the effects due to nitrogen more pronounced. Quality as measured by price is maximized with an average rate of 184 kg N/ha, a lower application rate than the 271 kg/ha required to maximize yield. The opposite prevailed for potassium fertilization with quality maximized with 330 kg K/ha and yield with 300 kg/ha. Average gross value of tobacco per hectare would be maximized with 242 kg N and 322 kg K, while net returns would be greatest at 237 kg N and 308 kg of K.
Effects of Fall Fertilization on Cold Resistance, Color, and Growth of Kentucky Bluegrass1
Authors: Wilkinson James F. , Duff D. Thomas
Published: July 2010

Fall fertilization of turf is usually avoided because it is thought to reduce cold resistance of plants composing the sward. Turf receiving N during this season exhibits color longer in fall and earlier in spring. The effects of periodic fall nitrogenous fertilization on the cold resistance, color, and growth of Kentucky bluegrass (Poa pratensis L.) were measured from September, 1970, to June, 1971, to ascertain if there is a period during the fall when N may be applied to produce color longer, yet not predispose plants to cold injury. Determinations of the cold resistance of crown tissue were made utilizing conductivity techniques for measurement of solutes diffused after cold treatment. Nitrogen at 2 kg N/200 m2 (as NH4NO3) was applied to different plots on October 1 and 15, November 1 and 15, and December 1 and 15, 1970. An additional treatment received 1 kg N/200 m2 on each date.

The cold resistance of all treatments increased through the fall and early winter, peaked near the end of January, decreased slowly through February, and was lost rapidly in March and April. Early fall fertilization (through November 1) resulted in the greatest reduction in cold resistance in the fall, while late fall fertilization (after November l) resulted in the greatest reduction in the spring.

Fertilization up until November 1 resulted in a color increase (i.e., chlorophyll increase) shortly after fertilization, and maintenance of color into early winter. Fertilization after November 1 did not produce substantial fall green‐up. All treatments produced good spring green‐up by mid‐March; however, late fall fertilized plots (after November 1) had a higher chlorophyll content by mid‐April.

No treatment produced any measurable topgrowth from the end of November until May. Plots fertilized before November 1 produced additional yields in the fall, while plots fertilized later produced additional yields in the spring.
Hypocotyl and Radicle Elongation of Cotton as Affected by Soil Environment1
Authors: Wanjura D. F. , Buxton D. R.
Published: July 2010

Cotton (Gossypium hirsutum L.) seedling growth during emergence was studied under controlled conditions to estimate the main and interacting effects of soil temperature, moisture, and physical impedance on hypocotyl and radicle elongation. This information additionally provided a data base for the development of an elongation model for an emerging cotton hypocotyl which is not included in this report. Soil temperature increasing from 15.6 to 32.2 C resulted in more rapid and greater total elongation of hypocotyls and radicles. Increasing physical impedance decreased elongation of both hypocotyls and radicles, with hypocotyls being the most sensitive. Decreased hypocotyl elongation was consistently noted with increasing soil moisture tension; however, radicle elongation tended to be greater at 3.0 bars than for .3 bar. A marked temperature‐moisture interaction was evident for hypocotyl and radicle elongation at 37.8 C which is near the hot null temperature (40 C) for cotton. However, this interaction did not exist at 15.6 which is near the cold null (14 C). A relative slow‐down in hypocotyl elongation rate between 2.5 and 5.0 cm occurred at 37.8 C and .3 bars soil moisture, and at 32.2 C and 3.0 bars.
Burning vs Incorporation of Rice Crop Residues1
Authors: Williams W. A. , Morse M. D. , Ruckman J. E.
Published: July 2010

The effect of burning and incorporating rice (Oryza sativa) straw on grain production and the N economy of the crop was evaluated over a 5‐year period in a field planted annually to ‘Colusa’ rice. An additional variable was vetch (Vicia benghalensis) planted in the previous autumn for green manure. The rice crop was fertilized annually at rates of 0, 45, 90, 135 kg/ha N.

The amounts of straw produced ranged from 33 to 85 ql/ha (dry), and the N concentration varied from 0.42 to 0.59%, depending on the N and vetch treatments. Amounts of N incorporated in the straw or presumably volatilized by burning the straw ranged from 13 to 50 kg/ha, and N uptake measured in the grain‐plus‐straw ranged from 38 to 115 kg/ha, but burning caused no measurable decrease in the uptake of N. Highest yields were obtained from 135 N or 90 N plus vetch. Vetch had a positive effect on yield equivalent to about 45 kg/ha of fertilizer N.

Five‐year averages of yields of grain show no measurable difference between burning and incorporation at any level of fertilizer or vetch N.
Aerial Thermal Scanner to Determine Temperatures of Soils and of Crop Canopies Differing in Water Stress1
Authors: Bartholic J. F. , Namken L. N. , Wiegand C. L.
Published: July 2010

An airplane‐mounted thermal scanner was used to measure irradiance in the 8‐ to 14‐μm wavelength interval over an extensively instrumented agricultural area. The area included soils differing in water and tillage condition, and replicated cotton (Gossypium hirsutum L.) plots with a wide range of plant water stress. The scanner data were recorded on analog magnetic tape and on 70‐mm film. The film densities of the various soil and cotton treatments and film calibration information were determined with a microdensitometer. The observed irradiances corresponded to cotton plant canopy temperature differences up to 6 C between the most and the least water‐stressed plots. The irradiance data from soils showed large differences as a function of time after tillage and irrigation. It is concluded that thermal imagery offers potential as a useful aid for delineating waterstressed and nonstressed fields, evaluating uniformity of irrigation, and evaluating surface soil water conditions.
Effects of North‐ and South‐facing Slopes on Yield of Kentucky Bluegrass (Poa pratensis L.) with Variable Rate and Time of Nitrogen Application1
Authors: Bennett O. L. , Mathias E. L. , Henderlong P. R.
Published: July 2010

Plant responses to differences in slope orientation have been observed for many years, but attempts to identify and measure specific responses and microclimatic factors are limited. Field studies were conducted near Morgantown, W.Va, during the 1966 to 1969 growing seasons to determine the effect of slope orientation on the yield of Kentucky bluegrass (Poa pratensis L.) treated with 0, 112, 224, 448, and 672 kg/ha rates of N applied singly and in up to four split applications. Slopes were approximately 35%. Soil on both slopes was Gilpin silt loam. The rate of growth, total yield, seasonal distribution of yield, and N recovery in plants were influenced greatly by slope orientation. Production on the north facing slope was more than twice that on the south‐facing slope. Splitting the N applications tended to produce a higher yield and more uniform seasonal distribution. More than 11,000 kg/ha of bluegrass forage were produced on the north‐facing slope in 1967 as compared to 4,000 kg/ha on the south‐facing slope. A combination of high soil temperatures and low soil moisture levels appeared to limit growth on the south‐facing slope. Maximum soil temperature on the north‐facing slopes were from 8 to 10 C less than on the south‐facing slope. Temperatures were measured 2.5 cm (1 in) below the soil surface under the bluegrass sod. Yield differences due to slope orientation completely overshadowed any yield responses from specific fertility treatments.
Effect of Leaf Color, Chlorohyll Concentration, and Temperature on Photosynthetic Rates of Isogenic Barley Lines1
Authors: Ferguson Hayden , Cooper C. S. , Brown Jarvis H. , Eslick R. F.
Published: July 2010

Leaf color and chlorophyll content may affect canopy temperature and, indirectly, plant metabolism and dry matter production. Photosynthesis (P), light saturation, specific leaf weight (SLW, mg/cm2), and chlorophyll content (mg/dm2) of barley lines isogenic for color were measured over a range of temperatures using plants grown in one field and two greenhouse experiments.

In the first greenhouse experiment P of all lines did not differ at temperatures of 20, 15, and 30 C. Differences in P occurred among three cultivars, but the differences between isogenic pairs were significant for the cultivar ‘Colsess’ only. In the second greenhouse experiment P was highest at 25 and 30 C, slightly lower at 35 C, and lowest at 15 and 20 C. P on a leaf area basis differed only for the isogenes of ‘Betzes’ but on a unit of chlorophyll basis was significantly higher for each pale green or golden member of an isogenic pair. Pale barley leaf blades had a higher light saturation point than normal green leaf blades. SLW was greater for the green member of one isogenic pair but not significantly different between members of other pairs.

Highest P of field grown plants occurred at 25 C. Green members of isogenic pairs had significantly higher P than pale green or golden members. SLW of field grown green isogenes was significantly higher than that of pale green or golden isogenes and higher than SLW of plants grown in the greenhouse.
Prediction of Available Soil Zn, Cu, and Mn Using Chemical Extractants1
Authors: Haq A. U. , Miller M. H.
Published: July 2010

The objective of this study was to evaluate various extractants for predicting available Zn in soils. The amount of Zn extracted from 85 soils by four extractants (EDTA, DTPA, EDDHA, and HCl + H2SO4), was related to the Zn concentration in corn (Zea mays L.) grown in the greenhouse for 16 days. The effect of other soil variables was determined by including them in a stepwise multiple regression analysis. EDTA and DTPA extractable Zn were superior to the other two extractants, with r values of 0.607 and 0.603, respectively. Of the soil variables tested soil pH had the greatest effect with an r value of −0.586. The inclusion of pH along with EDTA or DTPA extractable Zn gave R2 values of 0.745 and 0.759, respectively. For a given level of extractable Zn, the Zn content of corn increased with decreasing pH. The most significant finding of this study is the effect of pH on the use of EDTA or DTPA as a measure of available Zn. If these extractants are to be used for soils with pH values below 7.0, the pH must be included to obtain a satisfactory measure of available Zn.

The concentration of Cu and Mn in the corn was not closely related to the amount extracted by EDTA or DTPA. It was concluded that these extractants were not suitable for measurement of available Cu and Mn in the soils used in this study.
Influence of Nitrogen Fertilization and Other Factors on Yield, Prussic Acid, Nitrate, and Total Nitrogen Concentrations of Sudangarss Cultivars1
Authors: Harms C. L. , Tucker Billy B.
Published: July 2010

Herbage yields, total N, prussic acid, and nitrate‐N concentration of seven sudangrass [Sorghum sudanense (Piper) Stapf] forages treated with five levels of N (O, 22, 44, 88, and 176 kg/ha applied at seeding and after the first and the second clippings) were determined from a field experiment. The sudangrass cultivars represented included: sudangrass varieties (‘Piper’ and ‘Sweet’), sudangrass‐sudangrass hybrid (‘Trudan I’), forage sorghumsudangrass hybrids (‘Sweet Sioux’ and ‘Haygrazer’), and grain sorghum‐sudangrass hybrids (‘DeKalb SX‐11’ and ‘Horizon SP‐110’).

Yield increases from N applications were nonsignificant for the first clipping but increased with increasing N increments through the 88 kg N/ha for'clippings 2 and 3. Nitrogen fertilization increased total N, prussic acid, and nitrate concentration at each clipping. The Sudangrass varieties (Sweet and Piper) and sudangrass hybrid (Trudan I) were the highest in total N percentage. Haygrazer and Horizon SP‐110 generally contained the lowest N percentage.
Effect of Corn Stover on Phosphorus in Run‐off From Nontilled Soil1
Authors: Ketcheson J. W. , Onderdonk J. J.
Published: July 2010

Cultural practices can modify losses of soil and nutrients from cropland, but little quantitative information is available on the extent. In this study the effect of stover on soil and phosphorus (P) removal was determined for a well‐drained till soil (Guelph loam) with 7% slope. Corn (Zea mays L.) was planted without tillage after 32P‐tagged P fertilizer was applied broadcast and covered with a corn stover mulch in one treatment or left bare in a second treatment. Run‐off was collected and analysed from one simulated and from two natural rainfall events.

Stover reduced soil P in run‐off by 65% and fertilizer P by 97%. These reductions were achieved by a decrease in total run‐off and by a decrease in the concentration of suspended soil in it. Of the 29 kg of fertilizer P applied per ha, 3.85 kg (13%) and 0.13 kg (<1%) were removed over all run‐off events from the no stover and stover treatments, respectively. This corresponded to 8.5 and 1.3%, respectively, of the total P removal, which varied from 45 kg/ha without stover to 10 kg/ha with stover. The liquid fraction of the run‐off carried the least amounts of either soil or fertilizer P. Proportionately more fertilizer P was found in the coarse (>50μ) soil than in the fine fraction (<50μ), whereas proportionately more soil P was found in the latter than in the former, suggesting that fertilizer P is preferentially associated with the coarse fraction.
Interaction of Selected Pesticides and Rhizobium japonicum in Pure Culture and Under Field Conditions1
Authors: Kapusta George , Rouwenhorts D. L.
Published: July 2010

Investigations were conducted to determine the influence of selected pesticides on the growth of Rhizobium japonicum Kirch. Buch. in pure culture and in soil. In addition, nodulation and seed yield of inoculated soybeans [Glycine max (L.) Merr. cultivar ‘Wayne’] were studied under field conditions.

Commercial formulations of 24 pesticides were screened for bacteriostatic activity on rhizobia using a gradient plate technique. Isopropyl m‐chlorocarbanilate (chlorpropham) and o,o‐diethyl‐s‐[2‐(ethylthio)‐ethyl] phosphorodithioate (disulfoton) were the only pesticides that inhibited growth. In addition to these pesticides, 4‐(methylsulfonyl)‐2,6‐dinitro‐N, N‐dipropylaniline (nitralin) and 1‐napthyl N‐methylcarbamate (carbaryl) were selected for further study to substantiate the laboratory results.

Six U. S. Department of Agriculture rhizobia strains were cultured in pesticide‐amended medium 79 and subsequent growth was determined turbidimetrically. Nitralin exhibited little effect on the rhizobia, whereas chlorprophram, disulfoton, and carbaryl evoked a differential strain response.

Most probable number determinations of pesticidetreated soil samples indicated that naturalized soil populations of R. japonicum remained unaltered four weeks after pesticide application. Recommended rates of the pesticides studied did not influence soybean nodulation or seed yield.
‘Kenwell’ vs ‘Kentucky 31’ Tall Fescue under Grazing1
Authors: Carlson G. E. , Bond James , Hart R. H.
Published: July 2010

Differences in palatability, as measured in short‐term cafeteria grazing trials, are not always reflected in animal performance under season‐long grazing. ‘Kenwell’ tall fescue, selected for greater palatability, and ‘Kentucky 31’ tall fescue were grazed with yearling beef steers for 4 years. Mean stocking rate, average daily gain, and gain per hectare were all lower on Kenwell. Forage availability was the same on both varieties in 3 years, and higher on Kenwell in 1 year.
Leaf Number and Maturity in Hybrid Corn1
Authors: Allen James R. , McKee Guy W. , McGahen Joseph H.
Published: July 2010

Two field and two greenhouse experiments were conducted to study the effects of environmental factors and genotype on leaf number in hybrid corn (Zea mays L.) and the relationship of leaf number to maturity. Data were secured on leaf number, leaf area, plant height, and the time required from planting to either silking or tasseling, depending upon the experiment. For 126 commercial hybrids grown in four counties in 1968, leaf number was significantly correlated with plant height, silking date and moisture at harvest. For the same hybrid, leaf number was only slightly (generally one leaf or less) if at all affected by seed source and growing conditions, either locations in the same year or between years. In this experiment, hybrids were grouped by reputed maturity and grown in a location appropriate to their maturity. Results were similar in 1969 when 95 of the 126 hybrids were grown at one location. Under greenhouse conditions, where temperatures were comparable and soil fertility, water stress, and pests controlled, days to tassel in 16 hybrids and leaf number were significantly correlated with maturity rating and with accumulated solar radiation. When grown during two seasons, spring and summer, a hybrid required approximately the same number of langleys of solar and sky radiation from planting to tasseling even though mean elapsed days varied significantly between seasons, for the 16 hybrids a mean of 64.6 days versus 48.8 days, respectively. Based upon the results of this experiment and reports of other researchers, it is suggested that leaf number could be a characteristic of potential use in rating corn hybrids for maturity.
Crop Responses to No‐till Management Practices on Hilly Terrain1
Authors: Bennett O. L. , Mathias E. L. , Lundberg P. E.
Published: July 2010

Management practices are needed that will permit economic crop production in hilly terrain without excessive soil and water losses. Field studies were conducted over a 3‐year period to determine the effects of two rates of atrazine on yield of corn (Zea mays L.) sod planted in orchardgrass (Dactylis glomerata L.) for 2 years and to determine the residual effect of atrazine on germination and growth of 16 agricultural plant species the third year. Atrazine at 2.2 and 4.5 kg/ha was applied at planting time for sod‐planted corn and compared with two different methods of growing corn using conventional tillage. Regrowth of orchardgrass in sod‐planted treatments was measured following harvest of corn. Temperature and soil water measurements were made in sodplanted and conventionally‐tilled corn over a 2‐year period. Silage and grain yields were significantly higher from sod‐planted corn than from conventionally tilled corn. No soil losses were noted in areas where corn was sod‐planted as compared to heavy losses in conventionally‐tilled corn. Soil temperatures in no‐till corn averaged about 10 C less than under conventional tillage methods, with significantly higher amounts of available soil water present in no‐till plots than in conventionally‐tilled plots throughout the growing season. Residual studies with 16 different plant species indicated very little detrimental effect from residual atrazine after 2 years of application. Growth of many plant species was significantly higher following application of atrazine.
Photomicrographic Record of Light Reflected at 850 Nanometers by Cellular Constituents of Zebrina Leaf Epidermis1
Authors: Gausman Harold W.
Published: July 2010

Light reflected at the 850‐nm wavelength by cellular constituents of living Zebrina leaf epidermal cells was measured with a microspectrophotometer assembly to ascertain if discontinuities other than cell wall‐air interfaces in plant leaves contribute to infrared light reflectance. Results showed that cellular membranes and middle lamellae reflected more light than the surrounding protoplasm and cell walls, respectively. Therefore, it has been demonstrated that refractive index discontinuities other than cell wall‐air interfaces also reflect near‐infrared light.
Effect of Planting Date on the Yield and Fiber Properties of Three Cotton Cultivars1
Authors: Bilbro J. D. , Ray L. L.
Published: July 2010

For a number of reasons, cotton (Gossypium hirsutum L.) cannot always be planted at the most optimum time. Because information was needed relative to the effects of different planting dates on the yields and fiber properties of various types of cultivars, we studied for 5 years the responses of three cotton cultivars to planting dates. The planting dates each year were approximately April 20, June 1, June 10, June 20, and June 30.

As planting date was delayed, yields, lint percentages, fiber lengths, and micronaire units were reduced, and fiber strength was increased. Fiber elongation was not significantly affected by planting date. Yields, lint percentages, and fiber fineness varied significantly from year to year; and the years × planting date interactions were significant for all measured characters.

Averaged over all tests, differences among cultivars were significant for all characters studied. Although the relative performance of the cultivars was rather consistent (nonsignificant mean squares for cultivars × years, and cultivars × planting dates) over the range of environmental conditions encountered, generally the earlier the maturity of a cultivar, the less its yields and fiber properties were adversely affected by late plantings.
Influence of Tillage Depths and P‐Fertilizer Application Rates on the Yields of Annual Cropped Winter‐Grown Wheat1
Authors: Stibbe E. , Kafkafi U.
Published: July 2010

Because of different climatical conditions during the growing season from those of reported experiments in literature and the relatively few data about annual cropped winter‐grown wheat (Triticum aestivum L.) yield response to depth of tillage and to incorporation of previously broadcasted P‐fertilizer, a 2‐year field trial was conducted to evaluate the effects of three tillage depths, 10, 20, and 40 cm; and three P‐fertilizer rates on grain yields and dry matter production. The three P‐fertilizer rates were: no P‐fertilizer, 12 kg P/ha per 10 cm depth of tilled soil, and a flat 60 kg P/ha rate.

The field trial had a randomized split plot design with four replications and was simultaneously conducted on two soils of different texture.

Grain yields, dry matter production, and P‐uptake over 2 years were not influenced by depths of tillage. Initial development of wheat plants was better on shallow tilled soil. Added P‐fertilizer markedly increased grain yields, dry matter production, and P‐uptake. P‐fertilizer rates based on volume of tilled soil were as effective as the flat P‐fertilizer rate. Dry matter production response to P‐fertilizer was influenced by soil texture, indicating limiting P‐availability with decreasing clay content of soil.

From the data obtained it can be concluded that increasing depth of tillage has no significant effect on annual cropped winter‐grown wheat yields and secondly that there is no need to incorporate P‐fertilizer deeper than the top soil layer of 10 cm.

Therefore, if plowing a wheat stubble becomes necessary, P‐fertilizer rate can be based on the P‐availability of the sampled top soil layer after plowing and adjusted to the depth of the planned seedbed preparation to keep P‐availability at the recommended level for wheat growing.
Temperature Requirements for Seed Germination in an Annual‐Type Rangeland Community1
Authors: Young James A. , Evans Raymond A. , Kay Burgess L.
Published: July 2010

Germination as affected by constant and alternating temperatures was investigated in four species of annual grasses, soft chess (Bromus mollis L.); ripgut (B. rigidus Roth); slender oat (Avena barbata Brot.) and foxtail fescue (Vulpia megalura (Nutt.) Rydb.), and in their replacement forage species, seven cultivars and one naturalized population of rose clover (Trifolium hirtum All.); hardinggrass (Phalaris tuberosa var. stenoptera (Hack.) Hitchc.); and perlagrass (P. tuberosa var. hirtiglumis Bott. & Trobut). Temperature combinations were alternated through a 16 hr (night) and 8 hr (day). All combinations were used for −4, −2, 0, 2, 5, and 5‐degree increments through 40 C. The annual grasses germinated under a very broad range of temperatures above a minimum night temperature of 0 C. The rose clover cultivars germinated at lower temperatures, including subzero C (−4 C and −2 C) alternating with 15 to 25 C day temperatures. Seeds of rose clover from a naturalized population had lower germination at low temperatures and higher germination at high temperatures than the seven cultivars tested. In comparison with the annual grasses and rose clover, the perennial grasses were relatively restricted in the temperature regimes that permitted germination. Interpretation of the ecological significance of the results of monitoring seedbed temperatures during germination periods and the juvenile growth rate of the various species is dependent on the results of this investigation.
An Improved Technique for Making Wedge Grafts in Soybean Plants1
Authors: Sanders J. L. , Brown D. A.
Published: July 2010

The design and use of a grafting block for making uniform and reproducible wedge grafts in soybean (Glycine max (L.) Merr.) plants is presented. The grafting block was prepared from plexiglass measuring 14 ✕ 10 ✕ 1.2 cm. A slot to hold the scion was cut at a 2.5‐degree angle to the face of the block. The slot measured 4 cm in length, 0.3 cm in width, and varied in depth from 0.15 cm at the edge of the block to 0.0 cm at its termination point. The slot enabled a precise positioning of the scion for making the wedge cut. The block was used to successfully produce grafted plants which vary in the number of scions and roots. Six wedge grafts with different top:root ratios are described. The grafting block reduced the time required to make a graft and it gave an increase in the survival percentage of grafts. The uniformity of the wedge graft facilitated the interfacing of the scion‐root stock tissues, resulting in a more rapid recovery and uniform growth of the plant.
Influence of Seeding Dates and Methods on Establishment of Small‐seeded Legumes1
Authors: Fribourg Henry A. , Strand Rodney H.
Published: July 2010

A 2‐year study was conducted at three locations to evaluate the interactions between seeding dates and methods on alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and birdsfoot trefoil (Lotus comiculatus L.) establishment. Each species was seeded 16 to 18 times at each location. At one site, band and broadcast seeding methods and irrigation treatments were used at each date. Stand counts from randomly‐placed permanent quadrats were used to measure seeding success. Seeding date was critical to legume establishment. April to early May seedings were successful at all locations when weeds were chemically controlled. Acceptable stands were established also from seedings made from May to early June and from late July to early August at some locations. Alfalfa was less sensitive to seeding date than red clover or birdsfoot trefoil. Broadcast seeding was equal or superior to band seeding. One month of supplemental irrigation following seeding sometimes resulted in better stands.
A Cone‐Type Planter for Experimental Plots1
Authors: Peacock H. A. , Futral J. G. , Reid J. T.
Published: July 2010

A tool‐bar‐mounted 2‐row cone‐type planter was designed and built to seed experimental cotton (Gossypium hirsutum L.) plots. The unit planters equipped with sword openers, parallel adjustable wings, and split press wheels were fitted with cone‐type seeders, roller chain, and sprockets. Rows ranging from 4.60 to 21.85 m in length and from 50.8 to 101.6 cm in width can be seeded on top of a bed or on a flat seedbed. An endless nylon belt provides raking action in the cone‐type seeder, enhances even distribution of seed into the seed spout, and is the unique feature of our planter which facilitates planting machine‐delinted cottonseed. The plot planter, operated by one person besides a tractor driver, can be attached to any tractor of adequate size that is equipped with a 3‐point hitch.
Effect of Gravel Mulch on Crop Yield1
Authors: Fairbourn Merle L.
Published: July 2010

Research has shown that gravel mulch reduces soil water evaporation rate. A study was established to determine if this mulch material might be used to promote increased crop yields from the precipitation of semiarid regions. Treatments of gravel mulch, cornstalk mulch, and a control of bare soil were used in both laboratory and field experiments to observe their effect on soil water, soil temperature, and plant response. Evaporation of soil water was less and soil temperatures were higher under gravel mulch as compared with a bare soil surface. Increased crop yield on the gravel‐mulch treatment appeared to be due to an interaction of more soil water and higher soil temperature. Bare soil strips for crop rows and annual regeneration of the gravel mulch were necessary management practices to permit both crop production and maintenance of an effective mulch. The study has indicated that gravel mulch not only promotes increased crop yields but also has a potential for mechanized application and maintenance.
Relationship Between Tannin Content of Sorghum Grain and Preharvest Seed Molding1
Authors: Harris H. B. , Burns R. E.
Published: July 2010

Deterioration of grain by preharvest seed molding is a serious production problem of grain sorghum [Sorghum bicolor (L.) Moench] in areas where grain maturation occurs during wet seasons when temperatures are high. Differential preharvest seed molding among 49 commercial grain sorghum hybrids in hybrid performance tests conducted at Experiment and Midville, Georgia in 1971 was evaluated. The objectives were to investigate the consistency of hybrid reaction to seed molding and to determine the relationship between preharvest seed molding and seed tannin content. Preharvest seed mold severity was rated visually using an index scale of 1 (no more than a trace) to 5 (severely molded with 30% or more of grains deteriorated). Seed molding among hybrids was consistent at the two locations (r = 0.94**), indicating that the mechanism controlling preharvest seed molding was similar in the two environments. Seed tannin content was strongly correlated with preharvest seed molding indices (r = −0.89** at Experiment and r = −0.92** at Midville). The negative correlations and coefficients of determination indicated that 79 and 85% of the variability among hybrids for seed mold indices at Experiment and Midville, respectively, was due to high seed tannin associated with resistance. Seed molding was not related to time of 50% anthesis (r = −0.12); other factors conditioning resistance to seed molding were not identified.
Spectra of Normal and Nutrient‐Deficient Maize Leaves1
Authors: Al‐Abbas A. H. , Barr R. , Hall J. D. , Crane F. L. , Baumgardner M. F.
Published: July 2010

Since the advent of spectral mapping and identification of vegetation by remote sensing methods, information about differences in plant nutrient status has gained prominence. Therefore, we decided to study the reflectance, transmittance, and absorptance spectra of “normal” and six types of nutrient‐deficient maize (Zea mays L.) leaves. Nitrogen‐, phosphorus‐, potassium‐, sulfur‐, magnesium‐, and calcium‐deficient leaves were analyzed at 30 selected wavelengths from 500 to 2,600 nm. The analysis of variance showed significant differences in reflectance, transmittance, and absorptance in the visible wavelengths among leaves 3, 4, and 5, among the 7 treatments, and among the interactions of leaf positions and treatments. Only treatments in the infrared wavelengths produced significant differences.

The chlorophyll concentration of leaves in all nutrient‐deficiency treatments was lower than that of leaves in the control. Percent moisture in the S‐, Mg‐ and N‐deficiencies was higher. Positive correlations were obtained (r = 0.7) between moisture content and percent absorptance at both 1,450 and 1,930 nm. Second degree polynomial regression analysis of leaf thickness and leaf moisture content showed that these two variables were significantly and directly related (R = 0.894). Leaves from the P‐ and Ca‐deficient plants absorbed less energy than those from normal plants in the near infrared wavelengths; leaves from the S‐, Mg‐, K‐, and N‐deficient plants absorbed more than the normal.

Leaf thermograms were prepared on normal and S‐and N‐deficient leaves. Both S‐ and N‐deficient leaves had higher temperatures than normal leaves.
Air Temperature and Vapor Pressure Changes Caused by Sprinkler Irrigation1
Authors: Kohl R. A. , Wright J. L.
Published: July 2010

The downwind effect of evaporation from sprinkler spray was studied in the field to determine if air temperature and vapor pressure were changed enough to influence plant growth and water use. Wet‐bulb and dry‐bulb temperature profiles were measured upwind and at three distances downwind from a sprinkler lateral before and during sprinkling. Wind‐speed and direction were also measured. Air temperature generally was reduced less than 1 C, and vapor pressure in the air was increased less than 0.8 mb. This amount of change in the air temperature and humidity is not likely to be sufficient to cause any significant change in plant growth or evaporative loss of water.
Tillage Effects on Fallow Water Storage in the Eastern Washington Dryland Region1
Authors: Lindstrom M. J. , Koehler F. E. , Papendick R. I.
Published: July 2010

Early stand establishment of winter wheat (Triticum aestivum L.) is essential for efficient production and erosion control in much of the northwest U.S. dryland wheat region. Stand success depends on efficient storage and retention of winter precipitation and thus, on soil management practices which maximize infiltration and minimize evaporative loss during fallow. In this study fall chiseling (25 cm deep) and disking (13 cm deep) were compared with no tillage with respect to the effect on over‐winter water storage in the low precipitation (24 cm annually) region of eastern Washington. Tillage effects were evaluated during a mild winter with minimal soil freezing and during a cold winter with runoff conditions from rain and snowmelt on frozen soil. Three spring tillages, sweep cultivation (13 or 20 cm deep) or disking (13 cm deep), were superimposed on each of the fall tillages to evaluate effects on oversummer soil water retention, both deep in the profile and in the seed zone. In addition, these tillages were compared with a chemical fallow treatment with no tillage.

During the cold winter, fall chiseling increased water storage markedly and disking to a lesser extent as compared with no tillage (8.7 cm increase with chiseling, 2.3 cm with disking), but tillage had no effect during the mild winter. September to May storage as percentage of precipitation for this period was 87, 60, and 50% for chiseling, disking, and no tillage, respectively, for the cold winter, and 62% irrespective of tillage during the mild winter. The increase in water stored during the cold winter by chiseling was attributed to improved infiltration properties of the frozen layer associated with this tillage. Storage efficiency with chiseling was greater during the cold winter as compared with the mild winter largely because of differences in the nature of the precipitation. In the mild winter most precipitation fell as intermittent showers, whereas in the cold winter precipitation events were fewer but each was greater in amount.

Oversummer soil water loss (May to September) was not influenced by type of spring tillage; amounts lost ranged from 4 to 9% of the total profile water stored in May. Although oversummer loss increased with increases in total stored water, after the cold winter the amount of stored water in the profile at seeding time was still considerably greater for the plots which received fall tillage. Seed zone water at the end of fallow was generally increased with increase in total profile water content, and was higher where spring tillage was used as compared with chemical fallow.
Effects of Plant Population, Row Spacing, and Relative Maturity on Dryland Corn in the Northern Plains. I. Corn Forage and Grain Yield1
Authors: Alessi J. , Power J. F.
Published: July 2010

Narrow rows or equidistant planting of corn (Zea mays L.) has been beneficial in the Corn Belt. The concepts were evaluated at Mandan, N. D., to determine their influence under dryland conditions and in combinations with early‐maturing varieties which partially evade late season drought. The 68 and 85‐day relative maturity hybrids were grown at plant populations of 20,000; 30,000; 40,000; 60,000 and 74,000 plants/ha in 50 and 100‐cm spaced rows for 3 years. In 1968, a “wet” year, row spacing and maturity class significantly affected dry matter production, but only population influenced grain yield. Plant population and maturity class significantly affected grain yield in 1969 and 1970, but only population influenced dry matter in 1969. Interactions were not significant. Later‐maturing corn averaged 12% greater forage yield, but early‐maturing corn produced 19% more grain. Average grain yields increased from 2,600 to 3,070; 3,090; 2,960; and 2,680 kg/ha with progressive increases in population. Grain yield for 50 and 100‐cm rows averaged 2,890 and 2,870 kg/ha, respectively. Number of barren stalks increased and ear weight decreased with increased population. Optimum plant population for grain and forage ranged from 30,000 to 40,000 plants/ha.
Turfgrass Wear Simulator for Small Plot Investigations1
Authors: Shearman R. C. , Beard J. B. , Hansen C. M. , Apaclla R.
Published: July 2010

A mechanical turfgrass wear simulator was constructed for small plot investigations. It was developed for use on experimental units as small as 1m2. The wear simulator is operated by an electric motor and is constructed to rotate around a pivotal point with an adjustable diameter ranging from 1.0 to 2.7m. The machine is built of light weight materials in a size and weight so that it can be easily moved by an individual. The wear unit simulates both foot and tire wear on turf.
Response of Three Soybean Strains to Equidistant Spacings1
Authors: Wilcox J. R.
Published: July 2010

Three soybean [Glycine max (L.) Merr.] strains were evaluated in approximately equidistant spacings at 14 population densities ranging from 25,000 to 582,000 plants/ha (10,000 to 236,000 plants/acre) over a 2‐year period. The objective was to determine the response of the strains to a wide range of populations at equidistant spacings. Plant height, height of the lowest pod, and lodging increased with increasing plant population. Mature plant weight, seed weight per plant, and the ratio of mature plant to seed weight increased as population decreased. The three strains differed in their response to population density when seed yield was expressed per unit of area. Yields of L15 were most consistent across all populations. Yields of C1421 were most responsive to populations above 281,000/ha, whereas yields of C1477 were most responsive to populations below 83,000/ha. Maximum yields for C1477 and L15 were at 281,000 plants/ha and for C1421 at 456,000 plants/ha. Yield of C1421, which was most sensitive to high populations, did not vary significantly with a 27% increase or decrease in plant population from the optimum. Maturity date and seed size were not affected by changes in population.
Chemical Composition of Agropyron desertorum as Related to Grass Tetany1
Authors: Mayland H. F. , Grunes D. L. , Stuart D. M.
Published: July 2010

Grass tetany, a Mg deficiency of ruminants, accounts for significant economic losses to Western cattlemen during the spring grazing period on Agropyron desertorum. This nutritional deficiency may also occur when ruminants graze other temperate grasses, but the soil‐plantanimal factors leading to the problem are not well understood.

The objective of this study was to provide definitive data relating seasonal changes in the chemical composition of forage to the occurrence of grass tetany on semiarid grasslands.

The field experiment was established on two calcareous soils where grass tetany had previously occurred. Agropyron desertorum forage was harvested from both sites at regular intervals during the spring tetany period in each of 5 years. The forage samples were analyzed for mineral elements, N, total water‐soluble carbohydrates (TWSC), higher fatty acids (HFA), ash alkalinity, and aconitic acid.

High levels of N and HFA, which are known from other studies to reduce Mg availability to the animal, coincided with the occurrence of tetany. The low Mg concentrations measured in the forage probably provided only marginal levels of available Mg to the grazing animals. A rapid increase in the ratio of N/TWSC coincided with the onset of tetany, and may be the primary factor which indirectly decreases Mg availability and precipitates the occurrence of tetany. Although the relationship of the protein/energy imbalance to grass tetany has been suggested previously, as far as the authors are aware this is the first time that N/TWSC values obtained during the growing season have been documented in conjunction with the occurrence of grass tetany.