bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Tree Root Competition on Growth Response of Four Cool Season Turfgrasses1
Authors: Whitcomb Carl E.
Published: July 2010

Trees and turf are important elements in most landscaped and recreational areas. However, must turf research has been conducted in full sun far removed from trees. This study was initiated to determine the competitive ability of four cool season grasses subjected to three competition treatments beneath tree shade: (1) silver maple (Acer saccharinum L.) roots, (2) honeylocust (Gleditsia triacanthos L.) roots and (3) no tree roots. A connecting pot technique was used to maintain light intensity nearly uniform over tree shaded pots with and without tree roots. A fourth competition treatment was located in full sun separate from all trees.

Kentucky bluegrass (Poa pratensis L.) clipping yields were more affected by tree roots than the other three grasses. Effect of tree roots on perennial ryegrass was intermediate. Red fescue (Festuca rubra L.) and Poa trivialis responded similarly with or without tree roots suggesting a strong competitive ability. However, all Poa trivialis treatments with tree roots later became diseased.

Tree roots in some way reduced growth and vigor of most grasses even when water and nutrients were maintained at optimum levels. In addition to direct competition, biochemical inhibition (allelopathy) may be involved.
Nutritive Value Estimates in Apomictic Lines of Buffelgrass (Cenchrus ciliaris L.)1
Authors: Lovelace Dale A. , Holt E. C. , Ellis W. C. , Bashaw E. C.
Published: July 2010

The cell wall content of a forage and the digestibility of the cell wall determine to a large extent the digestibility of the forage. A study was conducted with buffelgrass (Cenchrus ciliaris L.) to determine whether cell wall digestibility differences among lines are related to components of the cell wall or the total cell wall content. Seven lines of buffelgrass were evaluated in an in vivo digestibility study. Leaf, stem, and whole plant samples of 15 lines were evaluated at two harvests in an in vitro digestion study. Significant differences in dry matter digestibility were detected among lines in both the in vivo and in vitro studies. About 66% of the variation in digestibility was associated with the digesibility of cell wall. Correlations of digestibility with various cell wall components or component ratios were not sufficiently high to be of significance for prediction purposes.

There were no differences among lines in in vitro dry matter digestibility of leaves, but there were for stems and whole plants. Differences in digestibility of cell wall were obtained for leaves, stems, and whole plants. Experimental lines differed in agronomic characteristics such as rhizome development, density, seed production, and color, but no significant correlations of these variables with digestibility could be shown. The most useful procedure for screening buffelgrass plants for quality seems to be in vitro dry matter digestibility with an associated neutral detergent fiber determination, whereby both cell wall content and cell wall digestibiity could be estimated.
Rice Response to Zn in Flooded and Nonflooded Soil1
Authors: Giordano P. M. , Mortvedt J. J.
Published: July 2010

Zinc deficiency in rice (Oryza sativa L.) has only recently been diagnosed. Although most Zn studies have been conducted on flooded rice, comparative data concerning the availability of Zn under upland and flooded soil conditions is needed. Therefore, rice (var. ‘Bluebelle’) was grown hi greenhouse pots on flooded and moist, limed Crowley sil (pH 7.5). Phosphorus, as concentrated superphosphate, was applied at rates of 20 and 200 ppm and Zn as ZnSO4, was applied at rates of 1, 4, and 16 ppm. Dry matter production and P uptake of immature plants were doubled and uptake of Zn was up to five times as great when the plants were grown on flooded rather than moist soil. The Zn concentration in the tissue decreased at the high P rate on moist but not on flooded soil. The percentage recovery of fertilizer Zn by the crop was greater from flooded than moist soil, especially at the high P rate.

Mixed and surface applications of Zn were comparable for flooded rice, whereas middepth placement (8 cm below soil surface) was less effective. Both surface and middepth placements were less effective than mixing under nonflooded soil conditions. Results of laboratory studies indicated that the mobility of Zn applied as ZnSO4 was comparable in flooded and moist soil. The amount of DTPA‐extractable Zn tended to be higher in moist than in flooded soil. This suggests that DTPA may not provide a reliable measure of Zn availability in flooded soils and that differences in Zn uptake may be related to root distribution or some other physiological or morphological characteristic of rice roots growing in moist or flooded soil.
Evaluation of a Sorghum Seed Treatment to Prevent Injury from Acetanilide Herbicides1
Authors: Eastin E. F.
Published: July 2010

The effects on sorghum [Sorghum bicolor (L.) Moench, ‘RS 626’] stand of alachlor [2‐chloro‐2',6'diethyl‐N‐(methoxymethyl) acetanilide] and acetochlor [2‐chloro‐N‐(ethoxymethyl)‐6'‐ethyl‐o‐acetotoluidide] were studied with and without 1,8‐naphthalic anhydride as a seed protectant. If sorghum could be protected from injury from these acetanilide herbicides, they could be used for the control of seedling johnsongrass [Sorghum halepense (L). Pers.], which are serious weeds in this crop. It was concluded that, under the conditions of the test, the anhydride seed treatment provided little protection and the anhydride alone was as injurious to the sorghum as herbicidal rates of the herbicides.
A Sorghum Planter for Small Experimental Plots1
Authors: Wiseman B. R. , Johnson R. , Widstrom N. W. , McMillian W. W.
Published: July 2010

A sorghum [Sorghum bicolor (L.) Moench] planter was fabricated to replace hand planting and to facilitate economical and uniform seeding of small experimental plots. Four basic units were used in constructing the planter, which seeds rows ranging from 2.84 to 6.35 m in length and 50.8 to 100.6 cm in width. In addition to more uniform seed placement, planting time was reduced by more than 50%.
Effect of Dry Season Drought on Uptake of Radioactive Phosphorus by Surface Roots of the Oil Palm (Elaeis guineensis Jacq.)1
Authors: Forde St. C. M.
Published: July 2010

The hypothesis that the feeding roots of the oil palm (Elaeis guineensis Jacq.) die back because of the effects of pronounced dry season drought in Nigeria was tested using radioactive 32P as a tracer to study P uptake as influenced by different levels of soil moisture. Two trials were carried out in 1964 and 1965, respectively, with the three treatments being: (A) no irrigation during the dry season and 32P applied in solution to the soil; (B) one irrigation of 50.8 mm of water shortly before application of 32P; and (C) irrigation at the rate of 50.8 mm of water per palm per week throughout the dry season and 32P applied to the soil. Leaf samples were taken and the activity of 32P was determined. In both trials the uptake of 32P in treatment C was significantly higher than either treatment A or B and supported the hypothesis that the lower activity was caused by the dieback of the absorbing roots during the dry season drought.
Relationships Among Black Layer Formation, Grain Moisture Percentage, and Heat Unit Accumulation in Corn1
Authors: Daynard T. B.
Published: July 2010

Two field experiments were conducted near Guelph, Ontario in both 1969 and 1970 with the objectives of (i) studying the relationship between grain moisture percentage and black layer development and (ii) examining the effect of environment on the length of the interval from planting or silking to black layer formation in corn (Zea mays L.). The first experiment involved 10 adapted commercial hybrids planted in early May at a plant population of 70,000 plants/ha. The second study concerned three commercial hybrids that were planted at a plant population of 55,000 plants/ha on each of four dates in 1969 (May 14 and 23, and June 5 and 13) and four dates in 1970 (May 6 and 20, and June 1 and 8). For both experiments records or measurements were taken of the date of 50% silking, 50% black layer, grain moisture percentage at 50% black layer, and final yield. Weather records were used to compute the number of accumulated heat units, by either the Ontario Corn Heat Unit (OCHU) or the 10‐ to 30‐C Growing Degree Day (GDDHU) systems, from planting or midsilking to 50% black layer.

Among adapted hybrids planted in May percent grain moisture at black layer varied from 30 to 37. For two hybrids planted on June 13, 1969 and June 8, 1970, black layers developed “prematurely” at a grain moisture of 39 to 42%. This premature black layer formation was an apparent consequence of cool weather during the week prior to black layer development.

Delayed planting resulted in a decrease in number of days from planting to midsilking, and an increase in number of days from mid‐silking to maturity (50% black black layer). Delayed planting resulted in an increased number of accumulated heat units from planting to midsilking, and a decreased heat unit accumulation from midsilking to maturity, by either the OCHU or GDDHU system. As a result, the number of accumulated heat units from planting to maturity was only slightly reduced by delayed planting date. The two systems were of comparable precision and were superior to number‐of‐days per se in characterizing the length of the interval from planting to midsilking, but not from midsilking to maturity.

Because of its ease of detection, black layer development can serve as a useful end‐point for characterizing corn hybrids as to their relative maturity and their adaptability to various localities. Present results suggest that there are significant problems, however, in the wide‐scale use of black layer development for this purpose.
Quantitative Removal of Major Nutrients by Three Pasture Grasses1
Authors: Duell Robert W. , Trout J. Richard
Published: July 2010

On the premise that fertilizer needs might be better understood if plant removal were known, the yield of N, P, and K was recorded for 15 harvests of field plots over 3 years. Tall fescue (Festuca arundinacea Schreb.), Kentucky bluegrass (Poa pratensis L.), and orchardgrass (Dactylis glomerata L.) plots were replicated times and were split to receive annual applications of A, 224‐98‐186 (kg/ha of N‐P‐K) half in spring, half in summer); B, 224‐0‐0 (scheduled as A); and C, 112‐49‐93 (spring only).

In individual harvests these grasses frequently differed in yield; percent N, percent P, and weight of N, P, and K removed. Combined analyses (five harvests/year for 3 years) confirmed differences among species in yield and percent N and P; in weight of elements removed by species, however, only the lower quantity of P removed by Kentucky blyuegrass was significantly different, averaging 50% less than the other grasses.

The decrease in K removal from NH4NO3 at 224‐0‐0 vs 224‐98‐186 was greater than decreases in removal of N, P, or dry matter. Seasonal and annual decreases in K were consistent.

When element removal was calculated as annual yield ✕ mean percentage of the element rather than the sum of the products of plot yield ✕ plot composition, significantly lower mean values for N and K (4.2 and 5.0% lower, respectively) were obtained. N and K percentages were significantly correlated with DM yields. Phosphorus percentage values did not correlate with DM yields. The discrepancy between the actual weight of P removed (by a grass at a fertilizer treatment in a given year) and the short‐cut calculation might be either positive or negative; a comparison between such extreme values would lead to large errors.
Use of the Thermogradient Plate as an Aid in Determining the Relative Vigor of Sweet Corn (Zea mays L.)1
Authors: Cole D. F.
Published: July 2010

Eighteen lots of sweet corn seed (Zea mays L.) were germinated on a one‐way thermogradient plate to establish a relative index for seed vigor. This index is based upon the rate and total germination over a temperature range of 13 to 43 C. Differences between lots were maximum 2 days after planting. The rankings after 4 and 7 days were the same. Significant correlations were obtained between the vigor index established with the thermogradient plate and data from percent emergence at 25, 35, 15:25 C in a controlled environment and rapid aging of 0, 4, and 7 days. The significant correlations indicate that the thermogradient plate can be used to detect differences in seed vigor of different lots of sweet corn in 4 days.
Acid Detergent Method for Reduction of Tannin Interference in Determining Lignin of Sericea Lespedeza
Authors: Donnelly E. D. , Wear J. I.
Published: July 2010

Apparent lignin was determined on stems and leaves of high‐ and low‐tannin sericea lespedeza (Lespedeza cuneata [Dumont] G. Don) by two methods. One method by which tannin, other acid‐soluble material, and protein are removed by detergents gave lower and more realistic lignin values than the conventional (H2SO4) method. Tannin was associated with high apparent lignin values when determined by the latter method. Genetic differences in lignin content among normal (high tannin) sericea lines and varieties were found, indicating that varieties lower in lignin than present ones can be developed.
Response of an Al‐Tolerant and an Al‐Sensitive Genotype to Lime, P, and K on Three Atlantic Coast Flatwoods Soils1
Authors: Long F. L. , Langdale G. W. , Myhre D. L.
Published: July 2010

Aluminum toxicity, calcium deficiency, and a complex of other unidentified factors contribute to the poor productivity of Atlantic Coast Flatwoods soils that occupy more than 100,000 km2 in the southern U.S. Our objective was to investigate the response of aluminum‐sensitive ‘Suregrain’ oats (Avena sativa L.) and aluminum‐tolerant ‘Starr’ pearl millet [Pennisetum typhoides (Burm. f)] lime, phosphorus, and potassium on Bladen, Leon, and Lakeland soils. Results of a series of pot experiments using four or more rates each of dolomitic limestone, monocalcium phosphate, and potassium chloride were used to calculate response surfaces and yield isoquants. Eightytwo to ninety‐five percent of the variation in yield was explained by lime, P, and K variables. Phosphorus was the most critical growth‐limiting factor for plant growth and response to P depended on lime and K levels.
Differential Phytotoxicity of Several Dinitroaniline Herbicides1
Authors: Murray D. S. , Santelmann P. W. , Greer H. A. L.
Published: July 2010

Research was conducted to compare the relative phytotoxicity of trifluralin (a,a,a‐trifluro‐2,6‐,dinitro‐N,N‐dipropyl‐p‐toluidine) with several analogues, and to establish an indices for comparing alternative structural substitutions. GR50 and visual injury values were used to evaluate relative phytotoxicities. There appeared to be a direct correlation between phytotoxicity and selected structural changes on the dinitroaniline ring. The dinitroaniline ring substitutions in order of decreasing phytotoxicity to bioassay indicator plants were substitutions in the one and five positions, one only, and four only. Least phytotoxic was the combined one and four position substitution on the ring.
Effect of Porous Rootzone Materials Underlined with Plastic on the Growth of Creeping Bentgrass (Agrostis palustris Huds)1
Authors: Ralston D. S. , Daniel W. H.
Published: July 2010

Recent developments in plastic barrier placement under compacted sand for regulated availability and retention of water (PURR‐WICK Rootzone) raises questions of duration of availability. Creeping bentgrass (Agrostis palustris Huds) was studied under putting green conditions when grown on replicated 1‐m2 plastic‐lined plots containing dune sand, mortar sand, calcined clay, diatomaceous earth, and peat. Soil was not included in any of the rootzone mixtures because of its inherent structural instability. In 1968 and 1969, some infiltration rates exceeded 150 cm/hr and all were greater than 7 cm/hr, therefore, water movement was considered ample.

The relative ability of the material in plots to retain moisture was measured by allowing the plots to dry‐down for 15 days between rains during August 1968 and for 17 days during July 1969. No irrigation was added to any plot until turf showed severe wilt. Bentgrass on plots containing the finer fractions of the dune sand, diatomaceous earth, various mixtures of sand, calcined aggregates, and peat did not require water for either period.

Comparison of the dune sand treatments with and without subsurface irrigation showed that a constant moisture level could be maintained in the subirrigated plots. Depth ranged from 20 to 50 cm with 40 cm proving ample.
Effect of Partially Acidulated Rock Phosphate and Concentrated Superphosphate on Yield and Chemical Composition of Alfalfa and Orchardgrass1
Authors: Lutz J. A.
Published: July 2010

Data from field experiments on the relative efficiencies to alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) of partially acidulated rock phosphate (PARP) and fully acidulated rock phosphate (CSP) is limited and additional information on this subject is needed. Crop response to sulfur has been obtained in certain southeastern states and more information is needed to determine if continued cropping with the use of sulfur‐free fertilizers may result in sulfur‐deficient areas in Virginia.

Florida rock phosphate was acidulated with H3PO4 at 20 and 100% of that required to convert rock phosphate to concentrated superphosphate. These two materials plus a check (O P) were applied as treatments for alfalfa and orchardgrass during 3 consecutive years in field experiments. Rates of total P for each crop were 0 and 100 kg/ha. The orchardgrass also received 25 kg/ha total P from CSP. The alfalfa received either 140 or 280 kg/ ha K from KCl or K2SO4. The orchardgrass, in addition to P fertilization, received N from NH4NO3 at rates of 168 and 280 kg/ha and K from KCl or K2SO4 at the rate of 140 kg/ha.

Both crops responsed to P fertilization each year. In each of the 3 years with alfalfa and during the last 2 years with orchardgrass the PARP was as effective as CSP. Added S did not significantly increase alfalfa yields but did cause a highly significant increase in orchardgrass yields in the last year of the experiment. The N concentrations of both crops were significantly affected by P sources, while the higher rate of N significantly increased the N concentration of orchardgrass. Average P concentrations in both crops were higher with CSP. The K concentration in orchardgrass was significantly affected by P source in 1969 and 1970 but not in 1971. The K concentration of alfalfa was significantly affected by source and rate of K. The S concentration of alfalfa was significantly affected by source and rate of P and K. The S concentration of orchardgrass was significantly increased by the higher rate of N and by K2SO4.

When both experiments were concluded significantly higher amounts of available P were present in the 0‐ to 15‐cm soil depth where PARP was applied.
Analysis of Interrelationships among Seedling Vigor, Field Emergence, and Yield in Wheat1
Authors: Das Gupta P. R. , Austenson H. M.
Published: July 2010

To evaluate various seed quality criteria, 86 samples of spring wheat (Triticum aestivum L. ‘Manitou’), obtained from farmers in 1969, were grown in the same year with and without Panogen 15 seed treatment in replicated field trials at three locations in Saskatchewan. Untreated seed samples were grown again in 1970 at one of the locations. Determinations were made in the laboratory of various seed and seedling characteristics supposedly related to seedling vigor. Grain yield was increased significantly due to Panogen 15 treatment by 2.5 and 4.9% at two of the three locations. Seed samples high in ‘unaided’ vigor as reflected particularly by a modified germination test of untreated seeds, showed little response to the fungicidal treatment. Yield variations between samples were most consistently dependent on standard germination, 02 uptake, and field emergence. It was concluded that the standard germination test could be supplemented with other tests to more reliably assess expected crop performance. The rate of 02 uptake by seed during the 8th and 9th hours of imbibition was found satisfactory. Further research to develop a rapid and efficient method of determining early seedling growth in darkness is recommended.
Measurement of Nitrogenase Activity of Intact Legume Symbionts In Situ Using the Acetylene Reduction Assay1
Authors: Fishbeck Kathleen , Evans Harold J. , Boersma Larry L.
Published: July 2010

The acetylene reduction assay has been used extensively to detect and measure nitrogenase activity of free‐living microorganisms, excised legume and non‐legume nodules, and root systems, soil cores, and entire nodulated legume plants removed from their soil medium. This investigation was undertaken to determine whether or not the acetylene reduction assay can be used to measure nitrogenase activity of cultures of nodulated soybean (Glycine max.) plants in situ and to compare the nitrogenase activity of these cultures with the nitrogenase activity of detached nodules and excised root systems from comparable cultures. Entire cultures grown in Perlite or in soil were placed in polyethylene containers, covered with Plexiglas lids, exposed to acetylene, and assayed for ethylene production. Time course experiments showed that rates of acetylene reduction of plants growing in Perlite and in soil were linear for at least 90 min following an initial lag period of 15 min. Saturation of nitrogenase in intact cultures was obtained at a pC2H2 of 0.1 atm. The apparent Km for nitrogenase was 0.05 atm. For convenience, assays in the large containers were conducted at a pC2H2 of 0.025 atm. The Michaelis‐Menten equation was used to calculate rates of acetylene reduction at saturating levels of acetylene. The correlation coefficient between rates of acetylene reduction and nodule fresh weight was 0.99 for plants of the same age and 0.79 for plants of different ages. Acetylene reduction rates of either intact nodulated plants in Perlite or nodulated root systems removed from Perlite were significantly greater than acetylene reduction rates of detached nodules from comparable cultures. Relatively little diurnal variation was observed in nitrogenase activity of potted plants grown under controlled environmental conditions. The method is useful for the assessment of nitrogenase activity of legume cultures in a porous medium under standardized conditions, but its application to legumes in soil proved to be complicated by the water content of the soil which influences rates of gas diffusion within the culture medium.
Rice Responses to Nitrogen Under High Solar Radiation and Intermittent Flooding in Peru1
Authors: Sanchez P. A. , Ramirez G. E. , de Calderon M. V.
Published: July 2010

The purpose of this study was to characterize the varietal responses of rice (Oryza sativa L.) to N fertilization in a tropical desert climate where extremely high N application rates are needed to attain maximum yields. Eight rice cultivars of contrasting plant type and growth duration were tested at applied N levels of 0 to 480 kg N/ha in a field experiment with an intermittently flooded water regime. Among the semi‐dwarf cultivars, the earlier maturing ‘IR8x2019; produced a maximum yield of 11.7 ton/ha at 480 kg N/ha and the later maturing ‘IR5’ produced a maximum yield of 9.9 ton/ha at 400 kg N/ha. Among the tall‐statured cultivars of the traditional plant type, the earlier maturing ‘CEL 895’ produced a maximum yield of 10.6 ton/ha at 320 kg N/ha and the later maturing ‘Minabir 2’ attained its highest yield of 7.9 ton/ha at 40 kg N/ha. Yield responses to N were primarily a function of effective tillering capacity and not of panicle size. Increases in dry matter production from panicle initiation to harvest were highly correlated with grain yields. A 0.85% N content in the above‐ground parts at harvest was associated with maximum yields as well as a total N uptake of approximately 180 kg N/ha, suggesting the existence of an internal N requirement for rice in this environment. The apparent recovery of added N averaged 30%, which is considerable lower than in constantly flooded environments.

The results indicate that: i) the shorter the growth duration of a cultivar within a specific plant type, the higher the yields and N response; ii) the extremely high N rates required are due to high levels of N uptake and low fertilizer recovery intermittent flooding.
Effect of Multiple Applications of 2,3,5‐Triiodobenzoic Acid (TIBA) on Yields of Stormproof and Nonstormproof Cotton
Authors: Freytag A. H. , Coleman E. A.
Published: July 2010

Field grown upland cotton (Gossypium hisutum L.) usually matures approximately 30 to 40% of the flowers that reach anthesis. Several investigators have shown 2,3,5‐triiodobenzoic acid (TIBA) to be successful in causing the retention of buds, blooms and pods of soybeans (Glycine max (L.) Merr.) Virtually no results have been reported on the use of TIBA to retain the 30 to 40% flower shed that occurs with cotton. Those who have applied TIBA to cotton have done so with single applications of higher rates than are reported here. This research is concerned with multiple applications of TIBA at lower concentrations.

Field studies were conducted over a 2‐year period with 2,3,5‐triiodobenzoic acid (TIBA) applications to cotton in multiple foliar applications, from two to five times at concentrations ranging from 5 to 62.5 g/ha on ‘Dunn 56C’ (stormproof) and (Acala 1517BR2’ (nonstormproof). Applications commenced at first blossom and continued for a period of up to 5 weeks at weekly intervals. Seed cotton yields were increased 8 to 16% by 5.0 g/ha applied five times, 25.0 g/ha applied three times, 62.5 g/ha applied two times, 62.5 g/ha applied three times, and 58.7 g/ha applied two times. First fruiting nodes in both cultivars were generally lowered; also boll counts and boll weight were increased with most TIBA treatments that increased seed cotton yield. No morphological response of dwarfing, epinasty, or leaf crinkling were observed with any of the TIBA treatments as had been reported by other workers for other crops.
Dry Matter Yield—N and S Concentration Relationships and Ratios in Young Corn Plants1
Authors: Terman G. L. , Allen S. E. , Giordano P. M.
Published: July 2010

Dry matter‐N and S concentration relationships and N/S ratios were studied in corn (Zea mays L.) grown in several greenhouse pot experiments on soil deficient in both N and S for good growth. Such relationships and ratios are basic to the proper interpretation of plant analysis results. Minimum concentrations in the dry forage necessary for continued growth of corn at 6 to 8 weeks were about 0.70% N and 0.045% S. Total N/S ratios varied widely from this ratio of 16, depending on age of plant, excess of N or S necessary for growth, and as a result of dilution of one nutrient by growth response to the other. This value of 16 at the minimum N and S concentrations approximates the ratio in plant proteins. Variations from the ratio of 16 indicate varying amounts of labile, nonprotein N or S.
Component Plant Part Development in Maize as Affected by Hybrids and Population Density
Authors: Genter C. F. , Camper H. M.
Published: July 2010

Maize (Zea mays L.) is used extensively as a silage crop. A relatively simple method is needed to evaluate hybrids for that purpose. Six maize hybrids, two each in early, midseason, and medium‐late maturity classes, were grown at four population densities over a 3‐year period. The hybrids were chosen on the basis of superior grain yield for their respective maturity class in previous tests. Populations were established at 34,600, 44,500, 54,300, and 64,200 plants per hectare. Data were obtained for each hybrid at each planting rate for grain and forage yield and on several other traits, including component plant: part ratios.

The early hybrids tended to be lower in grain yield, total dry weight, weight per ear, moisture at harvest, ear height, plant height, and proportion of stalks but higher in proportion of ears than the later hybrids. Shelling percentage, proportion of leaves, and stalk diameter showed differences between hybrids but no trend among maturity groups.

As population densities increased, total dry matter increased, whereas weight per ear, stalk diameter, and percent erect plants decreased. Plant and ear heights changed very little with changes in population density. Plants tended to become proportionately smaller as populations increased so that plant‐part ratios remained nearly the same. Barren plants were not included in the separation samples. Percent barren plants increased significantly with increased population density.

High energy feeds are needed by high‐producing, lactating cows and cattle on finishing rations. Maize parts vary greatly in digestibility. In the absence of feeding trials, plant‐part separation data and total dry matter production may be the most useful indicators of the relative values of maize hybrids for silage.
A Walk‐in Drying Room for Removing Moisture from Seed Crops of Forage Introductions1
Authors: Dolan D. D. , Braverman S. W. , Pfleger F. L.
Published: July 2010

A walk‐in drying room was constructed to remove field moisture from forage legume and grass harvested for seed. Steam at 48–50 p.s.i. was used as a heat source. The heat was transferred from thin coils to a moving air stream. Air flow was forced up or down through bags of drying plant materials. The temperature of the moving air may be adjusted, and there were 10 settings of circulation from completely recirculated air to completely exhausted air after a single cycle. Performance of the drying room was evaluated by drying 96 alfalfa (Medicago sativa L.) plants that had been separated into three components: tops, crowns, and roots. The initial moisture content was highest in the tops, intermediate in the crowns, and lowest in the roots. With the room operating at 43.5 C and with completely recirculating hot air, the tops dried most rapidly, crowns dried at an intermediate rate, and roots dried more slowly than either tops or crowns. At the end of 96 hours all three plant parts were equal in retained moisture content, and at 144 hours loss in weight had completely ceased and all three plant parts had attained stable dry weight.
Incorporation of 14C by Little Bluestem Tillers at Two Stages of Phenological Development1
Authors: Smith A. E. , Leinweber C. L.
Published: July 2010

The translocation and deposition of photosynthates in forage species is of great importance to forage quality. Sustained production of perennial forage species is influenced by the quantity of photosynthate deposited in storage organs. Phenological development is generally accompanied by changes in physiological characteristics which would ultimately influence carbon assimilation, translocation, and deposition. The objective of this study was to quantify 14C assimilation, translocation, and deposition in little bluestem (Andropogon scoparius Michx.) tillers during two stages of morphological development. Little bluestem tillers at two differing stages of phenological development were subjected to an atmosphere containing 14CO2 for 4 hours. Treated tillers were harvested at arbitrary time intervals over a 24‐hour period and samples of each morphological structure were analyzed. Most of the 14C activity was confined to the ethanol extract and residue fraction. No activity was detected in the water extracts or starch fractions at either stage of development. Results indicated that the general pathway for 14C incorporation was similar at both stages of tiller development. However, approximately twice as much activity was found in the culm bases and roots of tillers before culm elongation as in those of tillers whose culms had elongated 24 hours after treatment. The noticeable difference was attributed to the inclusion of actively elongating upper culms that accumulated much of the 14C activity in the latter stage of development. Sucrose was the only carbohydrate containing activity in the culm bases, which indicates that it is the form in which 14C is translocated from leaves to roots.
Subsurface Sweep for Applying Herbicides1
Authors: Reid J. T. , Peacock H. A.
Published: July 2010

Subsurface sweep applicators were designed and constructed using commercially available sweeps (25.4 cm wide) and spray nozzles. Performance was satisfactory, both in a replicated Upland cotton (Gossypium hirsutum L.) test and in a general field planting. Purple nutsedge (Cyperus rotundus L.) control was excellent, and there was a slight but nonsignificant increase in cotton yield. Precision placement of EPTC (S‐ethyl dipropylthiocarbamate) in both the horizontal and vertical planes was obtained with minimum disturbance to the profile of the finished seed‐bed. The device placed a 25.4‐cm‐wide band 5.1 cm under the soil surface. However, the same construction method could be used to make sweeps for other widths and depths of placement. Proper arrangement of the sweeps on a tool bar or cultivator can provide either band or broadcast coverage.
Effects of Seed Aggregation, Nutrient Availability, and Temperature on Germination of Subterranean Clover (Trifolium Subterraneum L.1
Authors: Caminos Juan , Raguse C. A. , Sumner D. C.
Published: July 2010

Germination percentage was increased and emergence was accelerated when two or more subterranean clover (Trifolium subterraneum L.) seeds were planted in close physical proximity instead of singly. The effect was enhanced when a nutrient solution was supplied. However, raising the ambient temperature from 10 to 15C and from 15 to 20C either reduced the effects of seed aggregation and nutrient availability or caused the effects to be evidenced during a shorter time interval. As the influence of close seed spacing and improved nutrient availability were more pronounced at cool temperatures, they therefore could be of importance to stand establishment from new seedings in the California annual range when rainfall adequate to permit germination occurs later than normal.
Some Effects of 2‐Chloroethyl‐phosphonic Acid (CEPA) on Burley Tobacco (Nicotiana tabacum L.) Cured Detached from the Stalk1
Authors: Gupton C. L. , Nichols B. C.
Published: July 2010

To make mechanical leaf harvesting of burley tobacco (Nicotiana tabacum L.) practical, the problem of physiological immaturity of leaves cured detached from the stalk must h,e solved. An ethylene releasing agent, 2‐chloroethyl‐phosphonic acid (CEPA), has been found to “ripen” plant leaves. The objective of this experiment was to determine if CEPA treatment before harvesting burley tobacco and curing it detached from the stalk alleviates the physiological immaturity of such tobacco.

Ten cultivars and breeding lines were grown in a split‐split‐plot design with genotypes as whole plots, methods of curing as subplots, and CEPA vs no CEPA treatments as sub‐subplots. Two weeks after topping and 4 days before harvesting, CEPA at the rate of 150 Mg/ plant was applied according to the experimental design. After curing, yield and grade index were determined for each treatment. Samples were then drawn from the leaf web, ground, and analyzed for percent total nitrogen, percent α‐amino nitrogen, water‐soluble acids, pH, percent ash, percent K20, percent nicotine, and percent nornicotine.

The method of curing significantly affected grade index, percent total nitrogen, percent a‐amino nitrogen, percent nicotine, and pH. CEPA treatment effects were statistically significant for percent total nitrogen, percent α‐amino nitrogen, and percent ash. The level of each of these constituents was significantly closer to that of stalkcured tobacco after leaves cured detached from the stalk had been treated with CEPA. CEPA‐treated Burley 37, Va 509, and 69‐517 cured detached had more tobacco graded usable by cigarette manufacturers than did tobacco with any other treatments. These results indicate that some important chemical constituents and physical characteristics are modified in a desirable direction by CEPA treatments. However, there may be detrimental effects, such as off‐flavor of the smoke, associated with CEPA treatments which would preclude using the chemical.
Effect of Ammonium and Nitrate Forms of Fertilizer‐N and their Time of Application on Utilization of N by Wheat1
Authors: Spratt E. D.
Published: July 2010

A hypothesis was tested: that NH4+‐N applied early and NO3−‐N applied later would be a beneficial cultural practice for wheat production. It is generally agreed that cereals prefer NH4+‐N during early growth.

One growth chamber and three field experiments were conducted with wheat (Triticum aestivum var. Manitou) using ammonium (NH4+‐N) and nitrate (NO3−‐N) sources of fertilizer‐N applied either at sowing or as the heads emerged or at both times. A nitrification inhibitor was used with ammonium sulphate to supply NH4+‐N and untreated calcium nitrate and ammonium nitrate were used as sources of NO3−‐N. Levels of nonassimilated mineral‐N (NH4+‐N and NO3−‐N) in the green leaves and stems of wheat varied widely according to the source of N applied and its time of application. High levels of NO3−‐N in the plant at flowering led to high percentages of N in the grain. Consequently, fertilizer‐N applied as NO3−‐N as the heads emerged (‘boot’ stage) increased the percent N (protein) in the grain more than NH4+‐N. Split applications of fertilizer‐N, with NH4+‐N applied at sowing (with a nitrification inhibitor) to give maximum leaf and stem growth and NO3−‐N applied at the ‘boot’ stage to increase grain protein levels, may be worth considering as an agronomic practice for wheat production, particularly if new cultivars could be developed to use effectively the increased leaf area to produce more grain. Also, manipulating the nitrogen metabolism of the wheat plants affected the uptake of other nutrients, for example, applying NH4+‐N increased P and Zn uptake.
Effects of Light, Temperature, KNO3, and Storage on Germination of Cogongrass1
Authors: Dickens Ray , Moore G. M.
Published: July 2010

Cogongrass (Imperata cylindrica (L.) Beauv.) was introduced into the southeastern United States and has become a pest in the Gulf Coast area. An efficient seed germination procedure would aid the study of control of this species. Seed were germinated in the laboratory to determine the effects of light, KNO3 temperature, and storage time on germination. Cogongrass germinated at temperatures ranging from 25 to 35C with optimum germination near 30C. Light increased both rapidity of germination and total germination. Neither rapidity of germination nor total seed germinated was affected by KNO3 in the presence of light. Germination in the dark was enhanced by KNO3. Cogongrass seed exhibited a gradual decrease in germination percentage over 13 months when stored in the laboratory.
Distribution of Corn Roots in Sandy Soil with a Declining Water Table1
Authors: Follett R. F. , Allmaras R. R. , Reichman G. A.
Published: July 2010

The purpose of this study was to relate the distribution of corn (Zea mays L.) roots to depth of a declining water table in a sandy soil association. Knowledge of root response to declining water tables is important for proper crop production management. Roots from 10 monoliths (91 cm deep), centered over and perpendicular to the corn row, were obtained at about full silk (August 26) from corn growing in 91‐cm rows. Water table depths ranged from 1.33 to 2.64 m at silking after declining at the rate of about 1.3 cm/day since July 1. About 20% of the evapotranspiration was supplied by natural precipitation with the remaining 80% from soil water depletion and the water table for the period from July 1 to September 16 (final harvest). Shoot growth was maximum at intermediate water table depths. An equation describing root distribution was obtained from a regression fit of root depth (Y) as a function of water table depth (X1) and cumulative root weight (X2). A similar fit was made using root length as X2. In no case was more than 10% of the total measured root weight or more than 20% of the total measured root length below 75 cm. The distribution of roots with depth indicates water requirements for corn in these sandy soils must be supplied to a root zone with maximum depth of about 100 cm.

Retarded root growth was observed where soil oxygen diffusion rate (O.D.R.) was less than 26 g/cm2/108 min. Such O.D.R. values were obtained at depths greater than 30 cm at the shallow water table site. Apparent normal root development occurred when O.D.R. values were greater than 30 g/cm2/108 min and matric suctions were about 100 mb.
Predicting Nitrogen Fertilizer Requirements After Land Leveling1
Authors: Thomas J. R. , Heilman M. D. , Lyles L.
Published: July 2010

Reduced yields and nutrient‐deficient crops on cut areas after land leveling are recognized problems. The objectives of this study were to determine if the variability in crop production between cut and fill areas of leveled fields could be minimized without overfertilization by adjusting the soils to a uniform level of available N based on the soils' capacity to supply N (N index) and to relate the N fertilizer requirement to the N index.

Five leveling methods which resulted in the removal of different amounts of top soil were used. Soils from leveled and nonleveled areas were incubated and the soils' capacity to supply N were described by the regression model N = a + bt1/2, where N is ppm of NO3‐N in the soil after t days incubation, and b is the N index. With a 14‐day incubation, the nonleveled soils supplied N at the rate of 174 kg/ha. Therefore, based on the leveled soils' ability to supply N in this time period, sufficient NH4NO3 fertilizer was applied to establish N levels of 174, 219, and 263 kg/ha. The leveled fields were cropped to forage sorghum (Sorghum bicolor (L.) Moench).

Dry matter forage yields, N uptake, and the growth rate during the first 19 days of growth were significantly related to the N index. Uniform crop production over the whole area was achieved when the available N level of the top 30 cm of soil was adjusted to 174 kg/ha, except on the conventional leveled soils where all of the top soil was removed. A regression model was developed that expressed the N fertilizer requirement as a function of the N index.
Response of Lowland Rice to Time and Method of Application of Phosphate1
Authors: Patrick W. H. , Peterson F. J. , Wilson F. E.
Published: July 2010

Field experiments were carried out for several years with lowland rice (Oryza sativa L.) to investigate methods and time of application of phosphate. Drill application of P at seeding was compared to topdressing 2 to 3 weeks after seeding. Topdressing at various times after seeding were also compared. Drilling phosphate fertilizer at seeding was superior to early‐season topdressing. Topdressing 2 weeks after seeding gave higher yields than topdressing later in the growing season.
Zinc Accumulation by Corn Seedlings as Influenced by Phosphorus, Temperature, and Light Intensity1
Authors: Edwards J. H. , Kamprath E. J.
Published: July 2010

Zinc deficiencies of corn (Zea mays L.) are often associated with cool, cloudy weather and appear to be intensified with high P fertilization. Experiments were conducted under controlled conditions to determine the effect of light intensity, temperature, and P on the uptake and translocation of Zn.

Corn seedlings were grown at 30,000 lux light intensity for 6 days in nutrient solutions containing either 0 or 0.1 mM P and at 18/14C or 30/26C day‐night temperatures. The seedlings were then exposed to Zn solutions of 0, 0.4, and 0.8 μM Zn for 48 hours with the same temperatures being maintained as during the initial growth period. Phosphorus pretreatment had no effect on Zn accumulation or translocation. At the low temperature there was very little uptake of Zn from an external solution.

In a second experiment, corn seedlings were grown for 6 days in a complete nutrient solution at light intensities of 19,300, 25,800 and 30,000 lux and temperatures of 18/14C or 30/26C. The seedlings were then exposed for 48 hours to treatments of 0, 0.4, and 0.8 μM Zn containing either 0 or 0.1 mM P. The initial temperature and light intensities were maintained during the uptake period. Phosphorus treatments did not affect Zn translocation to the shoots. Temperature influenced the translocation of Zn. More Zn accumulated in the roots at the lower temperature than at the higher temperature. Also, total Zn accumulation was reduced markedly as light intensity was decreased from 30,000 to 19,300 lux. At low light intensity Zn contained in the seed was the main source of Zn for young corn seedlings.

The shoot‐to‐root ratio increased with a high supply of P. With decreasing light intensity, root growth decreased and shoot.to‐root ratio increased. The effect of low light intensity in reducing root growth more than shoot growth appears to be an important reason for the occurrence of early season Zn deficiencies.
Chemical Regulation of Grass Growth. I. Field and Greenhouse Studies with Tall Fescue1
Authors: Elkins D. M. , Suttner D. L.
Published: July 2010

Growth control of grass and other vegetation has been achieved on a limited scale by the use of chemical retardants on highway roadbanks and similar rough turfgrass areas. A few chemical growth retardants are available commercially and a number of experimental chemicals have been developed recently. Five greenhouse experiments and four field studies were conducted from 1970 to 1972 at Southern Illinois University to evaluate commercial and experimental chemical retardants on ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.), one of the leading grasses used in Illinois for roadbank stabilization. Nineteen chemicals or formulations were tested with potted tall fescue in the greenhouse and several rates of eight different chemicals were evaluated under field conditions. On selected dates after treatment, grass plots were evaluated as to height, color maintenance, stand losses, and weed infestations.

In greenhouse trials the most promising results were obtained with Slo‐Gro, a maleic hydrazide (MH) formulation [diethanolamine salt of 6‐hydroxy‐3‐(2H)‐pyridazinone]; MON‐820 (N‐phosphonomethylimino‐diacetic acid); MON‐845 [N,N‐Bis(phosphonomethyl)glycine]; MBR‐6033 (3‐trifluoromethyl‐ sulfonamido‐p‐acetotoluidide); and Maintain CF‐125 (methyl‐2‐chloro‐9‐hydroxyfluorene‐9‐carboxylate, methyl‐9‐hydroxyfluorene‐9‐carboxylate, methyl‐2, 7 dichloro‐9‐hydroxyfiuorene‐9‐carboxylate). MBR‐6033 showed considerable potential in providing balanced control of growth while enhancing or maintaining a desirable green color. Sustaining color was difficult with other chemicals evaluated when used at rates sufficient to reduce growth over a long time interval.

MON‐820, MON‐845, Slo‐Gro (MH), and Maintain CF‐125 reduced grass growth and dry matter yield markedly at selected rates in field studies. However, color deterioration, stand reduction, and weed infestation were serious at higher chemical rates. MON‐814 (ethanolamine‐p‐nitrobenzene‐sulfonylurea), MON‐139 (phosphonomethylglycine, isopropyl‐ammonium salt), and MON‐464 (phosphonomethylglycine, calcium salt) were less consistent in reducing growth while sustaining color. Slo‐Gro, MBR‐6033, and Maintain CF‐125 effectively suppressed tall fescue seedhead development.

Information gained from these studies indicates that treatment with selected commercial and experimental growth retardant chemicals can result in effective tall fescue growth control and seedhead suppression. In some instances, chemical treatment of grass resulted in some degree of phytotoxicity and grass color losses. A notable exception was treatment with MBR‐6033 (Sustar), which gave good growth control while maintaining or enhancing grass color.