bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Element Accumulation by Populations of Corn (Zea mays L.) Selected for High and Low Accumulation of P1
Authors: Baker D. E. , Wooding F. J. , Johnson M. W.
Published: July 2010

The objective of the investigation of which this report is a part was to identify chemical elements, organic compounds, or metabolic processes which are associated with genetically controlled P accumulation in corn (Zea mays L.).

Two populations of corn, each with subpopulations selected for high and low P in ear leaves, were produced by randomly sib mating the F2 and five and six subsequent generations of an early maturing single‐crossed hybrid and a late maturing single‐cross hybrid. Each single‐cross hybrid contained homozygous inbred lines previously characterized as contributors of low and high concentrations of P to other single‐cross hybrids. In ear leaves, high P was associated with significantly higher, but not substantially different, concentrations of N and B. In seedling plants, grown for three weeks in a growth chamber, high accumulation of P was associated with higher concentrations of N and significantly higher concentrations of S, Ca, Cu, and B.
Effect of Seed Size upon Rate of Germination in Soybeans1
Authors: Edwards Calton J. , Hartwig Edgar E.
Published: July 2010

The rate of emergence of near‐isogenic soybean [Glycine max (L.) Merr.] lines that differed in seed size was measured when germinated in Sharkey clay at moisture levels of 20, 22.5, 25, 27.5, and 30%. Weight per 100 seed of lines used was 9.5 g, 13.6 g, and 22.6 g. No emergence was observed at 20% moisture. The small and medium seed size gave more rapid emergence and greater root development than the large seed at each soil moisture level where germination occurred.
Leaf Area Index, Tillering Capacity, and Grain Yield of Tropical Rice as Affected by Plant Density and Nitrogen Level1
Authors: Fagade S. O. , De Datta S. K.
Published: July 2010

To study the effects of plant density and N level on tillering capacity, leaf area index, and other growth characteristics and grain yield of flooded rice (Oryza sativa L.), we planted an improved tropical rice cultivar, ‘IR8,’ two experimental lines, ‘IR305‐4‐12‐1‐3’ and IR127‐ 80‐1‐10’, and a traditional tall tropical cultivar, ‘Peta,’ at three nitrogen levels in puddled soil. All cultivars were transplanted at five spacings and also broadcast. Of the three improved semidwarf rices, ‘IR305‐4‐12‐1‐3’ had the highest tillering capacity. Increasing plant density and nitrogen level increased the leaf area index (LAI) of all varieties at flowering. Broadcast‐planted plots had higher LAI values than transplanted plots. In the sunny dry season, broadcast‐planted ‘Peta’ had the highest LAI value, 14.6. In comparison, ‘IR127‐80‐I‐I0’, a low‐tillering line, had a LAI value of only 7.0. Grain yield increased with increased LAI values in the dry season, except for ‘Peta’ which lodged severely just after flowering. In the cloudy wet season, broadcast‐planted ‘IR8’ had the highest LAI value, 10.2, but it lodged. ‘IR8’ that was transplanted at close spacings did not lodge and it had higher yields. Thus even with an improved cultivar like ‘IR8’, grain yield declines at a high value if the crop lodges.
Influence of No‐tillage on Soil Moisture1
Authors: Blevins R. L. , Cook Doyle , Phillips S. H. , Phillips R. E.
Published: July 2010

Field studies were conducted to compare the effect of no‐tillage versus conventional tillage corn (Zea mays L.) production on soil moisture. The studies were made on a Donerail silt loam in 1968 and 1969 and on a Maury silt loam in 1970. Soil moisture was measured periodically at various depths in the soil profile during the growing seasons.

No tillage treatments had higher volumetric moisture contents to a depth of 60 cm during most of the growing season. The greatest differences occurred in the upper 0 to 8‐cm depth. Beyond a depth of 60 cm, systems of tillage had little influence on soil moisture during the growing seasons. Soil moisture curves indicate different water withdrawal patterns under the two contrasting methods of tillage. The decrease in evaporation and the greater ability to store moisture under no‐tillage produces a greater water reserve. This can often carry the crop through periods of short‐term drought and avoid the development of detrimental moisture stresses in the plant. The more efficient use of soil moisture by no‐tillage is reflected in higher corn yields. This study further substantiates the effectiveness of no‐tillage systems of corn production on well to moderately well‐drained silt loam soils in Kentucky and other regions with similar climatic regimes.
Relationships among Laboratory Germination, Greenhouse, and Field Emergence of Four Castor Seed Lots1
Authors: Stafford R. E. , Metzer R. B.
Published: July 2010

High‐, intermediate‐, and low‐germinating castor seed lots were evaluated for their performance in rolled germination paper, Kimpak, sterile sand, and field soil. High‐germinating seed gave similar results on the four substrates. Low‐ and intermediate‐germinating seed lots gave maximum germination in sterile sand and field soil. High positive correlations were found among all germination substrates. Laboratory germination in tetramethylthiuram disulfide (thiram)‐treated rolled germination paper at standard temperatures and germination on Kimpak at a constant 27 C were good indicators of seedling emergence in the field.
Effects of Defoliation Treatments on Morphological Characteristics and Carbohydrate Reserves in Kleingrass (Panicum coloratum L.)
Authors: Evers G. W. , Holt E. C.
Published: July 2010

Various management practices on kleingrass (Panicum coloratum L.) were evaluated in terms of yield, leaf area, tiller number, crown weight, stubble leaf area, and total non‐structural carbohydrates. Kleingrass was cut at 3‐, 4‐ and 5‐week frequencies at heights of 5 and 15 cm. Two dates of initial cutting in the spring‐were used. Yield was essentially uniform across all treatment combinations. Neither leaf area removed nor number of tillers removed was influenced by defoliation frequency, which indicates that tiller and leaf area development occurred at a constant rate. While these data indicate no critical stage in the defoliation of kleingrass, both crown size and stubble (residual) leaf area tended to be lower with 4‐week defoliation. All stubble, crown and growth parameters measured (tillers removed, leaf area removed, residual leaf area, crown size, and total non‐structural carbohydrates) except yield were favored by the taller cutting height. These results indicate a potential height effect on yield which may be reflected in subsequent performance.
Effects of Environmental Conditions and the Coadministration of Growth Retardants on the Response of Sugarcane to Foliar Treatment with Gibberellin1
Authors: Yates R. A.
Published: July 2010

Poor yields of sucrose from sugarcane are often associated with low sucrose:cane ratios, particularly when climatic conditions tend to favor stem elongation rather than sucrose accumulation. Plant growth regulators may be used to modify environmental effects on the growth of sugarcane and thus alter the balance between utilization and storage of sucrose. The objectives of this study were to investigate the influence of temperature, soil moisture, and the coadministration of plant growth retardants on the response of sugarcane to treatment with gibberellic acid.

Single foliar applications of GA (gibberellic acid) commercial sugarcane varieties (interspecific hybrids of Saccharum) stimulated stem elongation for from 2 to 6 weeks, but this response was not reflected in higher cane yields unless the plants were harvested within 6 weeks of treatment. A second application of GA at 4 weeks prolonged the growth response. In the field low temperatures were associated with the more prolonged growth responses, which were of smaller amplitude. Moisture stress had no apparent effect on GA response. No correlations were evident between environmental conditions or application rates and the duration of growth responses in greenhouse trials, but the amplitude increased with application rate within the range of 25 to 200 ppm. Three to five immature or semimature internodes were affected.

In field trials under warm conditions a period of growth retardation followed the initial GA‐induced growth stimulation. This did not occur in greenhouse trials. Stem‐sugar concentrations fell during the growthstimulation phase, but recovered as growth rates reduced. Attempts were made to accentuate this recovery, and so to increase the accumulation of sugars, by coadministration of growth retardants with GA. Dalapon had a delayed effect on cane growth, slightly curtailing the duration of the GA response, and suppressing growth thereafter. The phase of growth suppression was accompanied by increased stem sugar concentration in greenhouse‐, but not in field‐trials. Sodium silicate (at up to 200 ppm) had no significant effect on growth or sugar accumulation and did not modify the response to GA. Treatment with azauracil (at up to 400 ppm) strongly inhibited cane growth and increased stem‐sugar concentrations, but showed no significant interaction with GA.
Put‐and‐Take vs. Fixed Stocking for Defining Three Grazing Levels by Lambs on Alfalfa‐Orchardgrass1
Authors: Marten G. C. , Jordan R. M.
Published: July 2010

Pasture researchers disagree concerning which of two basic methods of establishing grazing intensity (put‐and‐take vs. fixed stocking) leads to valid experimental results. Our purpose was to compare these two methods of determining the influence of grazing intensity on pasture potential of a mixture of Medicago sativa L. and Dactylis glomerata L. We used three grazing levels within each method and measured daily gains of lambs and liveweight gains per ha.

The methods yielded similar animal daily gains and liveweight gains per ha over a 3‐year period. An increase within levels of either grazing pressure (put‐and‐take method) or stocking rate (fixed stocking method) caused a decrease in lamb daily gains, accompanied by and increase in liveweight gains per ha. The fixed stocking method resulted in understocking early in a season, which was offset by overstocking late in the season.

Fixed stocking gave lower experimental error for lamb daily gain, but the methods had similar errors for gain per ha. After the 1st year alfalfa comprised less of the mixture under light grazing pressures than under heavy pressures. However, by the 3rd year the percentage of alfalfa was nearly identical in all treatments.

We concluded that similar results can be obtained via put‐and‐take stocking and fixed stocking, provided the yield potential of the specific pasture type is known. The resources necessary to obtain yield potential of various forages under grazing in advance of a grazing trial represent a major disadvantage of a fixed stocking system.
X‐Ray Emission Technique for Determining Potassium in Corn Leaves1
Authors: Smid A. E. , Barnhisel R. I. , Peaslee D.E.
Published: July 2010

The micro‐distribution of K was determined in corn leaves (Zea mays L.) using a modified Heinrich miniature probe attachment for an X‐ray emission spectrometer. Concentrations of K were measured in 1 ✕ 5‐mm areas along a transect from the margin to the midrib. Increasing concentrations of K near the midrib were associated with the higher levels of K nutrition, whereas concentration peaks near the leaf margin were associated with the high plant population. Leaf tissue containing < 0.3% K was necrotic.
Effect of Root‐absorbed 2,3,5‐Triiodobenzoic Acid on Nutrient Absorption and Growth by Soybeans1
Authors: Ohki K. , McBride L. J.
Published: July 2010

Foliar application of 2,3,5‐triiodobenzoic acid (TIBA) has been recently used on soybeans [Glycine max (L.) Merr.] to enhance yields. Root application appeared as an alternative naethod of applying TIBA to the plant. This study was initiated to provide information on effects of root‐absorbed TIBA on growth, nutrient absorption, and nutrient distribution. Plants were grown, in Hoagland solution with TIBA at eight levels from 0 to l0 ppmw. Nutrients absorbed were determined by their disappearance from samples taken periodically.

Although young leaves and internodes showed no visible response at concentrations lower than 5 ppmw. typical symptoms were observed at 5 and 10 ppmw TIBA. The 10‐ppmw dosage reduced elongation of the stems. Roots were more sensitive than tops to TIBA, and morphological effects were observed as low as 0.1 ppmw. Shoot/root ratios showed that TIBA equally influenced the dry weights of these tissues. TIBA appeared to enhance the rate of P uptake from the nutrient solution. Within a 6‐day period 5 ppmw TIBA enhanced total P uptake about 25% above controls, while absorption of NO3‐N, K, Ca, Mg, Mn, and Fe was not influenced.
Inheritance of Nitrate Reductase Activity, Grain Protein, and Straw Protein in a Hard Red Winter Wheat Cross1
Authors: Duffield R. D. , Croy L. I. , Smith E. L.
Published: July 2010

An experiment was conducted in the field to estimate broad‐sense heritabilities on an individual plant basis for nitrate reductase (NR) activity, grain protein, and straw protein in a cross between two hard red winter wheat (Triticum aestivum L.) selections that differed substantially in grain protein. Phenotypic correlation coefficients were also determined between NR activity and grain protein, straw protein, water‐soluble protein, nitrate content, and yield.

Although heritability estimates for NR activity varied somewhat with sampling date, there was an indication that considerable genetic variability for this trait was present in the population. Genetic differences between parents were expressed during both fall and spring growth stages. Heritability estimates for grain protein ranged from 30 to 76%, with a mean of 44%. This range of heritability estimates is assumed to be partially due to removal of leaf samples for the enzyme assays. High heritability estimates for straw protein content at the earlier sampling dates suggested the presence of large genetic differences in efficiency of translocation.

The NR activity was significantly correlated with grain protein, water soluble protein, and nitrate content. Grain protein was negatively correlated with yield, but results suggested that successful simultaneous selection for high grain protein and yield could be accomplished. The results indicated that higher nitrate reduction and more efficient protein translocation were active in producing high grain protein. Since the genetic expression of the NR enzyme appeared to be quite sensitive to environmental and physiological conditions, further research is necessary to verify these findings and to more closely pinpoint the optimum conditions for successful selection.
Postharvest Cultural Practices Affecting the Rooting of Kentucky Bluegrass Sods Grown on Organic and Mineral Soils1
Authors: King J. W. , Beard J. B.
Published: July 2010

The effects of sod type, fertilizer placement, underlying soil type, soil moisture, sod harvest depth, and the postharvest irrigation rate on the transplant rooting capability were investigated. Market‐quality Merion Kentucky bluegrass (Poa pratensis L.) sod, grown on organic and mineral soils, was transplanted to grass‐faced root observation boxes. Root production data and counts of roots visible on the glass face were collected. Harvesting sod at a standard 2‐cm depth of cut was superior to 1‐cm in terms of root growth after transplanting. The 1‐cmthick sod was more prone to desiccation injury. Transplanting sod onto sandy loam topsoil of a 1:1 topsoilsubsoil mix resulted in increased root production compared to a clay loam subsoil. Transplanting sod to a dry soil resulted in delayed rooting. No difference in root production between soil‐incorporated and sod surface fertilizer placement was found in these short‐term studies. Sod grown on organic soil produced more roots in 16 to 24 days following transplanting than sod grown on mineral soil. Transplant sod rooting was impared during the May‐June period of extensive seedhead development.
Higher Fatty Acids of Flue‐cured Tobacco Leaves Varying in Stalk Position1
Authors: Chu H. , Tso T. C. , Chaplin J. F.
Published: July 2010

Cured leaves from eight stalk positions of three varieties and one breeding line of flue‐cured tobacco (Nicotiana labacum L.) were analyzed for fatty acid content and lipid residues. The higher fatty acids with 14 to 18 carbons were determined. The varieties analyzed were ‘Coker 139,’ ‘SC‐58,’ ‘NC‐95,’ and a breeding line ‘LN‐38.’ These varieties differed in alkaloid content and other physical and chemical characteristics. Leaves from SC‐58 and LN‐38 had the highest lipid residue. For all varieties lipid residues were lowest in leaves from the bottom stalk position and next lowest in leaves at the top position. LN‐38 had the highest total fatty acid content of any of the varieties. All varieties except Coker 139 yielded the highest total fatty acid content in leaves at the second stalk position. Also, the proportion of the unsaturated acid 18:3 was highest at position 2 in all varieties and decreased toward the top of the plant.
Amounts and Kinds of Sugars in the Nectars of Cotton (Gossypium spp.) and the Time of Their Secretion1,2
Authors: Butler G. D. , Loper G. M. , McGregor S. E. , Webster J. L. , Margolis H.
Published: July 2010

Nectar of cotton (Gossypium spp.) attracts many beneficial as well as harmful insects. Variations in the amount or quality of this nectar influences the number of these insect visitors. This paper deals with the amount, source on the plant, time of exudation, and sugar content of nectar produced by G. barbadense L. and G. hirsutum L. in Arizona. The nectar was collected in micropipets and the percentage of various sugars determined by gas liquid chromatography (GLC).

Leaf nectar on different plants, species, and dates varied from 0.70 to 19.00 µl/plant, sub‐bracteal nectar from 0.25 to 4.58 µl/flower, circumbracteal nectar from 0.22 to 2.00 µl/flower and floral nectar from 0.96 to 20.23 µl/flower. The concentration of fructose and glucose was greater than sucrose in the nectar from all sources. The volume of flower nectar in G. barbadense was five times that of G. hirsutum. The greatest amount of sugar in leaf nectar of G. barbadense was present at 0800 hours; in G. hirsutum at 1,100 hours. Fields of G. barbadense plants produced from 0.6 to 3.8 liters of nectar/ha/day. Some leaf nectar was secreted during the night.
Interaction of 2,3,5‐Triiodobenzoic Acid, Temperature, and Moisture on Soybean Development1
Authors: Ohki K. , McBride L. J.
Published: July 2010

Variations in plant response to foliar application of 2,3,5‐triiodobenzoic acid (TIBA) on soybean [Glycine max (L.) Merr.] under field conditions appeared to be related to temperature and soil moisture conditions near application time. Greenhouse and growth chamber studies were conducted to provide information on the interacting effects of temperature and soil moisture.

A 2 ✕ 2 ✕ 2 factorial experiment with soybeans in the greenhouse included two levels of premoisture, postmoisture and TIBA. Three temperature regimes simulating cool (21/16 C), warm (27/21 C), and hot (32/24 C) climates were additional variables to the greenhouse experiment for a 3 ✕ 2 ✕ 2 ✕ 2 factorial growth chamber experiment. Effects on plant height and reproductive development were studied.

The TIBA response, as determined from plant height measurements under greenhouse conditions, was reduced by soil moisture stress following TIBA application. Under growth chamber conditions the TIBA effect on plant height generally increased as temperature increased from cool to hot. Floral and/or pod abortion was enhanced under high soil moisture and high temperatures. TIBA applied at floral initiation aided in the retention of greater numbers of pods under high temperature and high soil moisture.
Legume Seedlings Stands Resulting from Winter and Spring Sowings in Kentucky Bluegrass (Poa pratensis L.) Sod1
Authors: Taylor T. H. , Foote J. S. , Snyder J. H. , Smith E. M. , Templeton W. C.
Published: July 2010

This study was designed to test the hypothesis that successful establishment of white clover (Trifolium repens L.) and alfalfa (Medicago sativa L.) may be realized if the seeds are sown on the soil surface of undisturbed Kentucky bluegrass (Poa pratensis) sod in late winter or early spring prior to the end of soil freezing and thawing.

Our data indicate that with a doubling of the seeding rate, establishment of these legume species is likely to be as successful from surface‐seeding in undisturbed sod as with seed‐coverage and normal rates of seeding.

Plantings made in December failed each year, mainly as a result of soil heaving. Legume stands resulting from plantings made below the soil surface, 0.6 cm (clover) and 1.6 cm (alfalfa), were superior to those obtained from surface seedings made in February, March, or April. Placing the seed below the soil surface was as important in February as in March or April. Plantings made in February, March or April had similar seedling stands in June. From the standpoint of seedling size in June, the February‐sown clover plants were much larger than those sown in March or April, indicating that clover may be sown to good advantage in February. Alfalfa did not show this response, suggesting little or no advantage for seeding it in February over doing so in March. Paraquat (1:1‐dimethyl‐4,4'‐dipyridylium dichloride) banded over the seeded row consistently enhanced seedling development. Seedbed preparation by tilling strips of soil 0.6 cm wide and 1.9 cm deep or 5.7 by 1.9 cm improved legume stands and increased seedling size over those of no‐tilled plots. Width of tilled strip had no effect on stands or seedling size.
Comparison of a Spent Boron‐phosphate Catalyst with Sodium Borate as a Source of Boron for Cotton1
Authors: Lewis D. E. , Wear John I.
Published: July 2010

Greenhouse and field experiments were conducted to evaluate NSC, a spent catalyst by‐product of the Monsanto Company, as a source of B for cotton (Gossypium hirsutum L.). Greenhouse experiments were conducted using Norfolk ls, Hartsells fsl, and Decatur cl. Soils were limed and fertilized for maximum yields with the exception of B, which was added from sodium borate and NSC, at rates of 0.5 ppm to 7.5 ppm B. High rates were to determine toxic effects. No increases in seedling top growth of cotton plants were obtained for B after 6 weeks growth in greenhouse tests. No reduction in seedling top growth was obtained on any soil at 7.5 ppm B, the highest rate of NSC. On Norfolk soil , plant concentration ranged from 43 ppm B with no B added to 352 ppm with 7.5 ppm B. Boron concentration of cotton on Hartsells soil ranged from 42 to 172 and from 67 to 131 ppm on Decatur soil at 0 and 7.5 ppm applied B, respectively. Seed cotton yield was increased in one of five field experiments from the addition of B from both NSC and sodium borate. On the other soils, there was no response to B from either source. Except on one soil type, leaf samples showed an increase in B content from all plots receiving B (from either source) when compared to no B added.
Crop Response to Phosphate Fertilization and to Residual Phosphate Levels: III. Greenhouse Experiment1
Authors: Giskin M. , Hagin J. , Kafkafi U.
Published: July 2010

The greenhouse experiment was performed as a supplement to the field experiments described elsewhere, having in view that crop sequence is faster and that yield response to fertilizers is more likely to be found in such experiments than in the field. The aims of the experiment were to evaluate the build‐up or depletion, during continuous cropping, of “available” phosphorus in soils with varying residual phosphate levels and to determine the contribution to yield of freshly applied and residual phosphates.

The pot experiment, with three soils and seven consecutive crops, received super‐phosphate in amounts of 0, 19.4, 58.2, and 174.6 ppm P/3 kg soil. After removal of the third crop each of the four initial treatments was divided into four subtreatment groups. Rates of fertilization remained similar.

A linearity of relationships was found between P‐uptake and total amount of fertilizer applied, dry matter yield and P extracted by NaHCO3 or water. For all three soils the freshly applied phosphate was more readily “available” than the residual phosphate but there was a decrease in dependence of yield response to freshly applied phosphate when the soil residual phosphate levels were high. In the Neve Yaar soil, the freshly added phosphate, expressed as ppm P in soil, produced roughly the same yield as an equivalent amount of NaHCO3‐extractable P. Whereas, in the Lachish soil, approximately two to three times more of fresh P has to be applied in order to approximate the same yield level of NaHCO3‐extractable P. This indicates a lower or slower fixation of phosphorus in the Neve Yaar soil and concurs with results found in the field experiments. Thus some quantitative relationship between plant response to freshly applied and residual phosphate was found which was not capable of being calculated from data of the field experiments.
Relationship of Seed Protein and Amino Acid Composition to Seedling Vigor and Yield of Wheat1
Authors: Lowe L. B. , Ayers G. S. , Ries S. K.
Published: July 2010

The seed of 17 phenotypes of a Mexican semidwarf wheat (Triticum aestivum L. ‘Inia 66’) was analyzed for protein and amino acid composition. These parameters were related to seedling vigor and yield to determine if amino acid composition would give a better estimate of potential vigor and yield within a genotype than seed protein.

The seedling dry matter showed a high positive correlation with seed protein content (r = 0.93***). Analysis of amino acids in acid hydrolysates of the seed indicated that mole percent glutamic acid was positively related to seedling growth (r = 0.84***). Several other amino acids were found to be negatively correlated. Twelve phenotypes of Inia 66 (four rates of N fertilizer × three nontoxic levels of simazine [2 chloro‐4,6‐bis‐(ethylamino)‐striazine]) from a Mexican field trial were grown for second‐generation grain yields in Michigan. A positive relationship was found between both seed protein content and mole percent glutamic acid and grain yield (r = 0.70** and 0.74**, respectively). Although the amino acid analyses elucidated the possible source of the protein contributing to increased seedling vigor, they did not prove to give a better estimate of seedling vigor, or yield than N analyses.
Effect of Soil Management on Corn Yield and Soil Nutrients in the Rain Forest Zone of Western Nigeria1
Authors: Agboola Akinola , Fayemi Adeboyejo
Published: July 2010

The problem of maintaining soil fertility by shifting cultivation is becoming increasingly difficult in Nigeria as rapid population growth places more strain on land resources, thereby decreasing the fallow period. Researchers are therefore confronted with the difficulty of finding an alternative low‐cost farming system that can maintain soil fertility.

An experiment on soil management practices involving both interplanted legume crops in rotation plus fertilizer was set up to investigate the above problem. The experiment was conducted in Ibadan, Nigeria, which has an annual rainfall of 140 cm and average temperature of 25 C. The experiment was located on Iwo soil series with unusually high available P (100 kg/ha) and exchangeable K (600 kg/ha), soil pH of 6.5, and CEC 15 meq/100g.

The results show that fertilizer (55‐10‐55 kg/ha of NP‐K) increased yields of corn (Zea mays L.) from 1,510 to 2,460 kg/ha. Legumes [greengram (Phaseolus aureus), cowpea (Vigna sinensis), and calopo (Calopogonium muccunoides)] either interplanted or rotated also increased the yield of corn. The magnitude of the increase for calopo was equivalent to that for the fertilizer. Legumes tended to conserve available P and exchangeable K in the surface soil.
Uptake and Assimilation of Ammonium‐N and Nitrate‐N and Their Influence on the Growth of Corn (Zea mays L.)1
Authors: Schrader L. E. , Domska D. , Jung P. E. , Peterson L. A.
Published: July 2010

Variations in response to ammonium and nitrate by different plant species including corn (Zea mays L.) quires further definition. Corn was grown in nutrient solutions under greenhouse conditions to investigate (1) uptake of ammonium and nitrate from the solutions and (2) the effect of ammonium and nitrate on growth, nitrate reductase activity, and accumulation of total N and nitrate in leaves, stems, and roots at four stages of development (21, 28, 40, and 47 days after planting). Uptake was determined by following the disappearance of ammonium‐N and nitrate‐N from nutrient solutions in which N was supplied in various combinations and rates. The nutrient solution treatments were as follows (ppm NO3‐‐N/ ppm NH4+‐N): 0/50, 0/100, 0/150, 50/0, 100/0, 150/0, 25/75, 50/50 and 75/25.

Fresh and dry weights per plant generally increased more rapidly when plants were provided 100 ppm of N as a combination of nitrate‐N and ammonium‐N (25/75, 50/50, or 75/25) than wherein 100 ppm of either nitrate‐N (100/0) or ammonium‐N (0/100) was supplied alone.

When both nitrate‐N and ammonium‐N were supplied, uptake rates of the two forms were similar. Uptake of nitrate was not retarded by the presence of ammonium, but assimilation of nitrate into organic N was retarded by ammonium. When both forms of N were absorbed, ammonium was used preferentially for synthesis of amino acids and protein.

Nitrate reductase activity was localized principally in the leaf blades and tended to be highest in plants provided a combination of nitrate‐N and ammonium‐N. Total N in the leaf and root tissues generally was higher in plants grown on ammonium alone or in combination with nitrate than in plants grown on nitrate alone. More nitrate accumulated in stem tissue than in leaf or root tissues. Amino acid composition of leaf tissue was not affected by the N treatments.
Recovery and Nutrient Content of Sandblasted Soybean Seedlings1
Authors: Armbrust D. V.
Published: July 2010

Soybean [Glycine max (L.) Merr.] seedlings were exposed to a 13.4‐m/sec wind velocity and wind plus sand (<1.17 mm diameter) for 0, 5, 10, and 15 min at 6 g/cm width/min to study the effect of wind and sandblast injury on their growth and nutrient content. Soybeans can tolerate a soil loss of 6 g/cm width for 5 min without a significant (5% level) reduction in vegetative yield. Exposures to wind or wind plus sand increased the nitratenitrogen concentration 443 ppm for the 5‐min wind treatment to 1,390 ppm for the 15‐min wind plus sand treatment. Iron concentration was increased only where vegetative production was unaffected, i.e., 5‐min wind, 5‐min wind plus sand, and 10‐min wind. Other nutrient concentrations were unaffected by the treatments. Sandblast injury can change a plant's metabolic processes before there is any visual damage.
Influence of Irrigation on the Yield and Persistence of Forage Legumes1
Authors: Wahab Hashim A. , Chamblee Douglas S.
Published: July 2010

The primary purpose of this study was to investigate the effect of irrigation on the yield and persistence of certain legumes as related to disease incidence. The effect of irrigation on the yield of three alfalfa (Medicago sativa L.) varieties, crownvetch (Coronilla varia L.), and ladino clover (Trifolium repens L.) was studied in the field over a 2‐year period. The nonirrigated plants received natural precipitation, whereas the irrigated legumes were supplied with supplemental water in addition to the rainfall whenever soil moisture was depleted to approximately 50% of the available water‐holding capacity. At the first harvest after irrigation in the 1st year, superior growth of all legumes was obtained by the use of supplemental water. The benefits of irrigation to some species and varieties ended at this point. Yields of alfalfa were sharply reduced in mid‐ and late summer of the 2nd year as a result of irrigation. Irrigation of the three alfalfa varieties resulted in an overall decrease in yield of 76% at the last harvest. The alfalfa varieties responded differentially to irrigation. Most of the stand of crownvetch was lost following the first cut on the irrigated plots.

In contrast to other legumes, irrigation increased the yields of ladino clover by approximately 19%.

Severe infestation by several diseases was probably a primary factor in the severe stand loss and low yields of alfalfa and crownvetch under irrigation. Excessive soil moisture due to precipitation soon after irrigation also possibly contributed to the loss of alfalfa stands.
Germination and Emergence of Crownvetch as Affected by Seed Maturity and Depth of Planting1
Authors: Peiffer R. A. , McKee G. W. , Risius M. L.
Published: July 2010

Because of the indeterminate flowering habit of crownvetch (Coronilla varia L.) some seedlots contain appreciable amounts of immature seed. Our objectives were (i) to study the relationship of seed maturity in ‘Penngift’ crownvetch as indicated by seedcoat and seedpod color to germination and emergence and (ii) to compare the emergence of ‘Chemung,’ ‘Emerald,’ and ‘Penngitt’ crownvetch; ‘Saranac’ alfalfa (Medicago sativa L.); ‘Pennscott’ red clover (Trifolium pratense L.); and ‘Empire’ birdsfoot trefoil (Lotus corniculatus L.). The development of Penngift crownvetch seed required 7 to 9 weeks with seedpods progressing through a sequence of color changes: green (3 to 4 weeks), greenish‐purple (1 to 2 weeks), greenish‐brown (1 to 2 weeks), tan and dull brown (1 to 2 weeks), and reddish‐brown (full maturity). Seedcoat color paralleled seedpod color. The total germination percentages (normal seedlings plus hard seeds) of seeds with greenish‐brown (immature), tan or dull brown, and reddish‐brown (mature) seedcoats were respectively, 30, 64, and 92. Immature seeds produced significantly fewer emergent seedlings from depths of 6, 13, and 25 mm than did more mature seeds. Emergence of seedlings of three cultivars of crownvetch from 19, 25, and 38 mm was 97, 98, and 76% of emergence from 13 mm. Crownvetch required 5 weeks for maximum seedling emergence, compared to 3 weeks for birdsfoot trefoil, red clover, and alfalfa. While under most field conditions the optimum planting depth for crownvetch is 6 to 13 mm, vigorous seedlings can emerge from depths of 25 to 38 mm.
Effect of Crust Rigidity and Osmotic Potential on Emergence of Six Grass Species1
Authors: Frelich James R. , Jensen E. H. , Gifford R. O.
Published: July 2010

Nonporous wax crusts were used to compare seedling emergence of tall wheatgrass (Agropyrun elongatum Host), pubescent wheatgrass [Agropyron trichophorum (Link) Richt.], basin wildrye (Elymus cinereus Scribn. and Merr.), Russian wildrye (Elymus junceus Fisch.), tall fescue (Festuca arundinacea Schreb.) and smooth bromegrass (Bromus inermus Leyss.). Seedlings were grown at O, −2.3, −4.4, −6.7, and −8.4 bars osmotic potential under soft, medium, and hard wax crusts, 3 mm thick. The treatments were designed to simulate the separate and combined effects of salty soils and crusts as limiting factors in seedling establishment in arid regions. The germination and emergence phases were separated by using only seeds that germinated as a basis for percent emergence.

Emergence of all six species was lower under hard crust than under soft wax crust. Pubescent wheatgrass and smooth bromegrass were most affected by the crust hardness. In the range of osmotic potential used, there was no reduction in emergence as osmotic potential was reduced when the emergence was taken at 2 weeks; however, reduction in osmotic potential did delay emergence. The delay was slightly longer for hard crust than for soft crust.

Although osmotic potential did not reduce emergence under soft crusts, a combination of low osmotic potential and hard crust did reduce the emergence of tall wheatgrass, basin wildrye, and Russian wildrye. The emergence of pubescent wheatgrass smooth bromegrass, and tall fescue was reduced principally by the hardness of the crust. Tall fescue was least able to penetrate the crust.

The results indicate that osmotic potential may be less important in reducing emergence of field seedlings than is the presence of a crust. In a field situation the slower rate of emergence and low osmotic potential may involve additional crust strength as the soil surface dries.
Iron Utilization by Efficient and Inefficient Sorghum Lines1
Authors: Mikesell M. E. , Paulsen G. M. , Ellis R. , Casady A. J.
Published: July 2010

Iron‐efficient and Fe‐inefficient sorghum [Sorghum bicolor (L.) Moench.] inbred lines and their F1 hybrid differed in response to Fe deficiency. These lines were used in growth chamber studies with a soil and with several liquid‐nutrient media to determine Fe‐use efficiency. An Fe‐deficient Colby silt loam soil (5.2 ppm DTPA extractable Fe) with 22.4 kg Fe/ha and without added Fe was used for a potted‐soil, growth study. In the remaining studies seedlings were grown in Hoagland nutrient solution to induce Fe deficiency, to determine effects of P levels and Fe sources, and to measure root reduction potential. The respective solutions used were: (i) 0.2‐strength solution with no Fe; 2.0 μM Fe and 3.0 mg CaCO3/ liter; 2.0 μM Fe and 5.0 mM P; 2.0 M Fe and 2.5, 25.0, and 10.0 μM Cu, Mn, and Zn, respectively; (ii) 0.5‐strength solution with 10.0 μM Fe at O, 0.5, 1.0, 2.5, and 5.0 mM levels of P; (iii) 0.5‐strength solution with 10.0 μM ferric and ferrous Fe; (iv) 0.2‐strength solution containing 2.0 μM Fe with the last 24 hours' growth in a ferrichloride‐ferricyanide solution.

Plants from all studies were separated to roots and shoots, wet‐ash digested, and assayed for Fe, Cu, Mn, Zn, Ca, and Mg by atomic absorption spectrophotometry. Phosphorus was determined by the vanadomolybdophosphoric method.

The Fe‐efficient inbred usually maintained lower P concentrations in shoots and commonly in roots under Fedeficient conditions. Antagonism from other nutrients except P was not involved consistently in differential response of Fe‐efficient and Fe‐inefficient lines. Root reduction potential for ferrichloride‐ferricyanide was lower for sorghum than for other crops, but did not differ between inbred lines. Shoot and root growth was always greater with ferrous than with ferric Fe. Efficiency of Fe use by sorghum apparently was not inherited by the hybrid. Iron efficiency in sorghum probably can be improved by accumulating genes that increase uptake of Fe, or by decreasing interference of P in utilization of Fe.
Effects of Date and Depth of Planting on the Establishment of Three Range Grasses1
Authors: McGinnes William J.
Published: July 2010

The optimum depth of planting for cool‐season introduced grasses under field conditions on range lands, particularly on the Central Great Plains, has received limited study. Whereas most previous studies on date of planting have been with fall planting, the author has had considerable success for 15 years with spring experimental plantings in northern Colorado. The following experiment was conducted to determine the optimum spring planting date, to find the optimum depth for spring seeding, and to evaluate date and depth of seeding interactions.

Crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.], pubescent wheatgrass [A. trichophorum (Link) Richt.] and Russian wildrye (Elymus junceus Fisch.) were planted at depths of 1.3, 2.5, 3.8, and 5.1 cm on average dates of planting of April 4, April 18, May 4, May 20, and June 9, 1967 through 1970 north of Fort Collins, Colo. Crested wheatgrass and Russian wildrye were also planted at the same depths on average dates of planting of April 20, May 3, May 18, and June 8, 1968 through 1970 on Central Plains Experimental Range (CPER) near Nunn, Colo. Establishment was evaluated from seedling counts made in September of the year of planting. At Fort Collins the greatest average number of seedlings was obtained from the April 18, May 4, and May 20 dates of seeding. Although year‐to‐year variations were great, the most reliable establishment was from the April 18 planting. At CPER, establishment from the June 8 planting was markedly poorer than for the three earlier dates of planting. Number of seedlings per meter of row was essentially the same for 1.3‐ and 2.5‐cm planting depths within species and locations except that crested wheatgrass averaged 12% more seedlings from 1.3‐ than from 2.5‐cm depths at Fort Collins. At 3.8 cm, numbers declined to about 50% of those in the shallower depths and declined still more at 5.1 cm. The decline was about 50% as much for pubescent wheatgrass as for crested wheatgrass and Russian wildrye, Soil moisture in the zone 2.5 to 5.1 cm deep appeared to be most critical for establishment. When moisture at this soil depth averaged less than 12% following seeding, stands contained only 53% as many seedlings as when the soil moisture averaged above 12%.
Yields and Magnesium Uptake by Plants as Affected by Soil pH and Calcium Levels1
Authors: Christenson D. R. , White R. P. , Doll E. C.
Published: July 2010

Liming of acid soils may influence Mg uptake either because of associated pH factors or because of Ca level as the result of liming. This study was conducted to determine the effect of Ca levels and soil pH on the yield and uptake of Mg by oats (Avena sativa, cultivar ‘Gary’).

Treatments in one experiment included a control, 118 ppm Al as Al2(SO4)3, 506 ppm Ca as CaCO3, 506 ppm Ca as CaCO3 plus 506 ppm Ca as CaSO4, and 1,012 ppm Ca as CaCO3. In a second experiment two Mg levels (0 and 12 ppm Mg as MgSO4·7H20) were applied in combination with two Ca sources at two Ca levels (0 ppm Ca, 800 ppm Ca as CaSO4, and 800 ppm Ca as CaCO3).

Uptake of Mg was not increased by the addition of CaSO4 either in combination with Al2(SO4)3 or CaCO3. Uptake of Mg was significantly greater (5% level) when 800 ppm Ca as CaCO3 was applied than when 800 ppm Ca as CaSO4 was applied.

Application of Mg significantly (5% level) increased Mg uptake regardless of Ca level or source.

These results suggest that soil pH level affected Mg uptake more than did Ca level.
Distribution of Nutrients in the Rice Plant and Effect of Two Nitrogen Levels1
Authors: Westfall D. G. , Flinchum W. T. , Stansel J. W.
Published: July 2010

The use of plant analysis as an aid in making fertilizer recommendations and diagnosing nutritional disorders in rice (Oryza sativa L.) has potential as a production tool. This field experiment was designed to study the distribution of N, P, K, Ca, Mg, Mn, Fe, and Zn in rice plant parts at the panicle differentiation stage of plant development when grown under recommended (134 kg N/ha) and inadequate (67 kg N/ha) N fertility in order to determine the effects of these factors on plant analysis results.

Rice plants grown with inadequate N fertility were lower in N, Mg, Mn, Fe, and Ca in most plant parts analyzed than their counterparts grown with recommended N fertility. The concentration of P was not influenced by N fertility rate. The concentration of plant nutrients varied with plant part and leaf age. The concentrations of N, P, and K were highest in the younger, fully matured leaves and decreased with leaf age. The concentrations of N, Ca, Mg, and Fe in the second leaf were higher than in the whole plant samples.

Both plant parts analyzed and N fertility level in which plants were grown influenced nutrient analysis. The second leaf appears to be more closely correlated with the nutrient needs of the plant at panicle differentiation. As a production tool, the second leaf, or the most recently fully expanded leaf, is recommended to be collected for tissue analysis.
Yield and Protein Responses to Nitrogen Fertilizer of Two Winter Wheat Varieties Differing in Inherent Protein Content of Their Grain1
Authors: Johnson V. A. , Dreier A. F. , Grabouski P. H.
Published: July 2010

Genes that increase the grain protein potential of wheat (Triticum aestivum L.) are known. The interaction of such genes with factors of the production environment, particularly soil nitrogen availability, determines their probable value and contribution to higher protein content in wheat.

Two hard winter wheat varieties differing inherently in the protein content of their grain were grown in replicated plots at selected sites in Nebraska over a 3‐year period. Nitrogen fertilizer was applied at five rates in the 1st year and at seven rates in the 2nd and 3rd years. Data were recorded for yield, test weight, and protein content of the grain.

Significant protein responses to nitrogen fertilizer occurred in all trials. Responses of both varieties were linear and positive. C.I.14016 maintained a protein advantage of 2 percentage points over ‘Lancer’ at all levels of fertilizer. The protein advantage of C.I.14016 over Lancer was independent of the relative yields of the two varieties. The feasibility of effectively increasing the grain protein content of wheat by breeding is indicated by the data.

Statistically significant yield responses to fertilizer were recorded in 6 of 10 trials. Yield responses of both varieties were nonlinear with the second‐degree polynomial providing a good fit of the data. Less nitrogen fertilizer was required for maximum yield of Lancer, the lower protein variety, than for C.I.14016. Test weight responses of the varieties to fertilizer were negative and linear. The test weight of Lancer was higher than C.I.14016 at all fertilizer rates.
Use of Sprinklers to Study the Influence of Population Density Upon Seed Cotton Production in an Arid Area1
Authors: Robinson Frank E. , Cudney David
Published: July 2010

The growing period for cotton (Gossypium hirsutum L.) has been shortened by 2 months in the Imperial Valley because of an invasion by pink bollworm. The law now requires that cotton residue be incorporated into the soil early to lower the number of overwintering larvae. The shorter period for floral development led to reexamination of yield potential under different plant spacing. Defoliants, fertilizer, desiccants, and insecticides for pink bollworm control and water were applied through the sprinkler system. Randomized block designs of ‘Stoneville 213’ and ‘Paymaster 111A’ included plant densities of 15,000, 60,000, 242,000, and 969,000 plants/ha on a flat soil surface. Seeds were placed by hand at 2 per dibble in a square grid pattern. The bolls per plant were significantly affected by plant density. The effect of plant density on boll weight was significant on Paymaster 111A but not on the Stoneville 213. The highest seed cotton yield occurred where the plants produced the greatest number of bolls per hectare. For both varieties the highest yield occurred in the 242,000/ha treatment, with 4,870 kg/ha in Stoneville 213, and 4,228 kg/ha in Paymaster 111A. A trend of lower micronaire in the highest density was noted in each variety.