bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Kentucky Bluegrass Cultivars Using Nitrogen‐Deficient Culture1
Authors: Nittler L. W. , Kenny T. J.
Published: July 2010

Because there is difficulty in identifying seed‐lot purity of some Kentucky bluegrass (Poa pratensis L.) cultivars, we conducted these studies to find characters in which cultivars might differ. Seedlings were grown in sand and were supplied with a nutrient solution lacking nitrogen. Three weeks after planting, striking differences in color of first leaf blades were evident. Those of some plants were entirely green but in others they were strong red. Between these extremes there were plants in which only part of the leaf blade was light red. Of 30 cultivars and experimental lines tested, 5 had a high percentage of plants with strong‐red leaf blades, and 2 cultivars had a high percentage with green leaf blades. In the other 23 cultivars most plants had partly red or slightly red leaf blades. Although differences observed would not be useful in distinguishing many cultivars, they could be used to separate contrasting types.
Combined Effects of Low Oxygen and Salinity on Germination of a Semi‐dwarf Mexican Wheat1
Authors: Aceves‐N Everardo , Stolzy L. H. , Mehuys G. R.
Published: July 2010

The simultaneous occurrence of low oxygen and high salinity conditions is common in a wide range of irrigated soils. The combined effects of O2 and osmotic potential stresses on germination of wheat (Triticum aestivum L. ‘Inia 66’) were tested under growth chamber conditions. A range of O2 concentrations and salinity levels were chosen to simulate soil aeration and salinity combinations that might be expected to occur in well‐aerated, fine‐textured, saline, and saline‐sodic soils. Daily observations of number of seeds germinated and days to first germination were recorded. Analysis of variance of percent germination was performed in three different ways: i) using the original data, ii) using the arcsine transformation, and iii) deleting most of the 0% germination values to get better estimates of the error terms.

Inia 66 showed tolerance to high salinity and low O2 during germination. Close to full germination occurred at a salinity level of −6 bars (21% O2) and at 2% O2 (no salinity stress). However, the combination of high salinity with low O2 depressed germination below economic levels. Predicted osmotic potentials associated with a 50% decrease in germination ranged from −10.8 bars at 21% O2 to −3 bars at 1% O2. High salinity levels were more limiting than low O2 concentrations. Days to first germination were increased only at O2 concentrations lower than 5%. Apparently this concentration is the threshold at which germination is delayed at all the osmotic potentials tested. A function is proposed for predicting days to first germination under saline but good soil aeration conditions.
Wheat Growth Related to Rhizosphere Temperature and Oxygen Levels1
Authors: Sojka R. E. , Stolzy L. H. , Kaufmann M. R.
Published: July 2010

Although extensive research has been conducted on the separate effects of various soil‐temperature levels and various soil‐oxygen levels on wheat growth, little work has been done on the interaction of soil‐temperature and soil‐oxygen levels upon wheat response. Mexican semi‐dwarf wheat (Triticum aestivum L. em Thell cv Yecora) was grown in soil at regulated temperatures under greenhouse conditions to measure response to varying combinations of root zone oxygen levels and soil temperatures. Components of dry weight production, tillering, leaf area, stomatal aperature, and leaf xylem tension were measured.

Decreasing soil‐oxygen levels reduced total, root, and top dry weight components and root/shoot ratios, reduced leaf area, and retarded tillering. Soil temperature of 15 C generally favored higher total, shoot, and root dry weight, and a lower root/shoot ratio, increased leaf area, and increased the number of tillers per plant at harvest compared to 9 and 21 C. Stomatal closure (as measured by a diffusion porometer) occurred at very low soil‐oxygen levels, but no consistent aeration or temperature effect on leaf water potential was observed. Low soil temperature and low soil oxygen levels interacted to retard shoot development pointing to a dependence of shoot development on root metabolism.

The data underscore the need to characterize both soil temperature and soil oxygen availability when considering either parameter separately in order to fully understand the relative oxygen status of plant roots.
Effect of N Fertilization on Yield and Water Use Efficiency of Dryland Winter Wheat as Affected by Stored Water and Rainfall1
Authors: Singh Ranjodh , Singh Yadvinder , Prihar S. S. , Singh Piara
Published: July 2010

Dryland wheat is raised on stored water and limited precipitation. Nitrogen is known to increase grain yield and water use efficiency. But the crop response to N in relation to stored water, effect of N on water extracttion, effect of stored water and rainfall on water use are not sufficiently understood. Field experiments were conducted for a 3‐year period on clay loam (Haplustaff) and loamy sand (Ustifluvent) soils using four rates of N viz. 0, 40, 80 and 120 kg N/ha to probe the above aspects in two‐gene dwarf dryland winter wheat. Stored available water varied from 133 mm in a 180 cm profile to 204 mm in 120 cm profile and the rainfall varied from 62 to 141 mm.

Maximum grain yields and response to N application increased with increasing water storage irrespective of growing season rainfall. Compared with a control, N application increased yield, water use, and water use efficiency under all situations. Differences in water use and water extraction pattern by unfertilized and fertilized wheat were small during early stages. But after 80 days, 80 kg N/ha increased water depletion from 60 to 180 cm layer by 25 to 300%.

Under comparable rainfall, 52 mm higher initial available‐water storage in clay loam than in loamy sand, caused 90 mm greater water depletion from 180 cm profile. With adequate moisture in the lower layers, a heavy rain during tillering followed by a long dry spell induced deeper rooting which depleted all the available water from 180 cm profile.
Growth and Nutrient Accumulation and Distribution in Grain Sorghum. I. Dry Matter Production and Ca and Mg Uptake and Distribution1
Authors: Jacques G. L. , Vanderlip R. L. , Whitney D. A.
Published: July 2010

Calcium and magnesium have been found deficient in grain sorghum [Sorghum bicolor (L.) Moench] in some areas. To conduct fertility trials and interpret plant tissue nutrient analyses, we must first understand the growth and nutrient uptake and distribution patterns of the plant. Studies were conducted to investigate growth and Ca and Mg uptake and distribution in grain sorghum throughout its growth cycle. Two grain sorghum hybrids (‘RS 610’ and ‘RS 702’) were planted at the Kansas State University Agronomy Farm, Manhattan, Kan., in 1970 and 1971. Weekly samples were analyzed for Ca and Mg in the plant parts.

Dry matter production and Ca and Mg uptake were similar in both hybrids, although a larger proportion of dry matter and Ca and Mg were distributed in vegetative portions of RS 702 than in RS 610. Environmental factors affected growth and nutrient uptake both years, but patterns were similar.

Calcium and Mg concentrations varied among plant parts, and concentrations within a plant part were not constant throughout sorghum's growth cycle. Plant‐part nutrient concentrations generally were high early in the growth cycles and decreased as the plants reached maturity, except that Ca content in leaf blades increased with maturity. Whole plant Ca and Mg concentrations decreased almost linearly throughout each growing season.

Calcium and Mg distributions in plant parts were not proportional to dry matter distribution. Only a small percentage of the plant's total accumulated Ca was in the grain at maturity, when the grain accounted for nearly half of the total plant weight. There was evidence of translocation of Mg from culms to developing grain, but Ca seemed to be immobile.

Calcium and Mg uptake preceded dry matter production, and Ca was generally taken up more rapidly than Mg during vegetative growth. When vegetative growth had been completed, more than half of the plant's total Ca and Mg uptake had occurred.
Laboratory Evaluation of Quality in Subtropical Grasses. III. Genetic Variation among Digitaria Species in In Vitro Digestion and its Relationship to Plant Morphology1
Authors: Klock M. A. , Schank S. C. , Moore J. E.
Published: July 2010

In vitro organic matter digestion procedures (IVOMD) were used to evaluate a wide range of Digitaria spp. (digitgrass) breeding lines at three stages of maturity, across 11 field replications of one genotype, and as full‐sib families evaluated at two locations and with two fertilizer treatments. Observations were made on the effect of flowering culms and stem microanatomy on digestibility. Information on the variation in digestibility among digitgrass hybrids and factors which may affect digestibility would be useful in selecting promising genotypes early in a breeding program.

At 3, 5 and 7‐week regrowth, IVOMD ranged respectively from 69.8 to 77.7, 56.6 to 68.4 and 50.7 to 64.0% on different lines. Lines lower in digestion at 3‐week re‐growth were lower at 5 and 7 weeks, and lines initially higher in digestion usually remained higher at all three harvests. Eleven field replications of a clonally propagated genotype did not differ significantly, nor did three laboratory replications per sample. Significant differences in IVOMD were detected not only among hybrid families, but also within some of the families (among full sibs).

A factorial analysis was performed on IVOMD data on five hybrid families. Significant differences in digestion among genotypes, families, levels of fertilization, and location were observed. The genetic portion constituted the greatest single component of the total variance. The range in IVOMD was 53.9 to 76.3% among genotypes and 57.8 to 73.1% among families. Genotype IVOMD correlated directly with family mean for each harvest. A highly significant negative correlation (r = −0.81) was found between percent IVOMD and percent seed stalks. Micro‐scopic examination revealed that genotypes with low digestion showed more evidence of secondary cell wall thickening in nodal regions of the stem than did those genotypes with high digestion.
Phalaris and Tall Fescue Forage Production as Affected by Nematodes in the Field1
Authors: Hoveland C. S. , Rodriguez‐Kabana R. , Berry C. D.
Published: July 2010

Nematodes are known to damage cool season perennial grasses, but effects on forage yields in the southeastern U.S. are unknown. Forage yield losses of two cultivars each of tall fescue (Festuca arundinacea Schreb.) and phalaris (Phalaris aquatica L.) were studied in a central Alabama field experiment on Augusta fine sandy loam (Aerie Ochraquult) soil. Yields were measured on untreated soil and on soil treated with methyl bromide (MB) or carbofuran nematicide (CN). Second‐year total forage yields of ‘Kentucky 31’ tall fescue were increased 107% with MB and 39% with CN above that of untreated soil. ‘AP‐2’ phalaris forage yields were increased 348% with MB and 172% with CN. Autumn and early winter production was affected most by the soil treatments. Sod populations of stubby root (Trichodorus christiei Allen.), stunt (Tylenchorhynchus claytonia Steiner), and lance (Hoplolaimus galeatus (Cobb) Thorne) nematodes increased by the second season and then declined. Populations of plant parasitic nematodes were decreased by MB and CN treatments. Nematodes destroyed grass roots at depths beyond 10 cm, and plant stand losses occurred during autumn drought. Nematode susceptibility contributed significantly to poor performance of tall fescue and phalaris on sandy soils. Other soilborne pathogens also may be a factor in causing root damage.

These results indicate that nematodes are important in the persistence and production of phalaris and tall fescue on sandy soils of the southeastern U.S. Breeding for host plant resistance to nematodes will be necessary to extend the geographical range of these grass species.
Performance of Spring Sown Triticale, Oats, Barley, and Wheat1
Authors: Oplinger E. S. , Youngs V. L.
Published: July 2010

Triticale (X Triticosecale) has recently been promoted as a high protein livestock feed. In order to determine its suitability for this purpose we compared the yield, test weight, protein content and lodging of triticale with that of adapted cultivars of spring oats (Avena sativa L.), barley (Hordeum vulgare L.), and wheat (Triticum aestivum L.) at four locations in each of 4 years in Wisconsin.

Triticale cultivars averaged 16.9% protein concentration in the whole grain, while wheat, oats and barley cultivars averaged 15.5, 14.2 and 12.5% protein, respectively. However, wheat, oats, and barley produced higher grain yields and more protein on an area basis. Maximum protein yield was produced by Dal oats, a recently released high protein cultivar. The triticale cultivars were taller than the other species, but they had good standability up to maturity. Triticale was later in maturity, harder to thresh, and of considerably higher ergot content than the other spring species.
Estimating Relative Leaf Water Content with a Simple Beta Gauge Calibration1
Authors: Obrigewitsch R. P. , Rolston D. E. , Nielsen D. R. , Nakayama F. S.
Published: July 2010

Existing methods for periodically measuring plant water status require considerable instrumentation or time. The method described herein simplifies plant water measurement by providing a completely linear calibration between attenuated beta radiation through a plant leaf and its relative water content simply by measuring the radiation intensity through the leaf at only two water contents — full turgidity and complete dryness. A 14C beta source was used with leaf discs from sugar beets (Beta vulgaris L.). The method includes a means for drying the leaf discs while maintaining the original geometry. Measurements on leaf discs at relative water contents between O and 1 show that the method is accurate, and that a calibration can be established using a standard method to ensure full turgidity and complete dryness without the added necessity of determining the mass of the leaf. Thus, after proper calibration, only radiation intensity measurements are required to determine the relative water content of a leaf.
Yield Response to Soil Warming: Economic Feasibility1
Authors: Schimisseur W. E. , Boersma L. , Rykbost K. A.
Published: July 2010

The development potential of soil warming with power plant waste heat is evaluated and major determinants to development are identified by evaluating the economic feasibility of producing selected crops by soil warming. Yield responses to soil warming were identified from a series of test plot experiments. Crop values and soil warming production costs are specific to Willamette Valley, Ore., in 1973. The capital cost of a soil warming installation consisting of 5.08 cm diameter PVC pipes buried 90 cm deep at 183 cm centers with supply lines and pumps was estimated to be $8,213/ha. The annual amortization would be $847 or $l,242/ha at interest rates of 10 and 15%. Additional operating and maintenance costs would result in total annual costs of $927 or $l,407/ha at opportunity costs of 10 and 15%.

Only high value crops could be profitably produced using soil warming. The economic potential of the proposed production technique is limited by the high capital cost of the installation. This potential could be improved by decreasing installation costs through the use of wider spacings, by selection of crop cultivars more responsive to soil warming, and by accepting lower interest rates on the invested capital.
Alfalfa Flower Color Associated with Differential Seed Set by Leaf‐cutter Bees1
Authors: Goplen B. P. , Brandt S. A.
Published: July 2010

Many studies have been carried out to demonstrate that alfalfa (Medicago sativa L.) plants vary in their attractiveness to bees. Flower color has often been implicated as one of the factors in attractiveness, but the reports are conflicting and inconclusive. Field observations by the authors indicated that yellow flowered alfalfa plants were tripped less frequently and set less seed than the common purple flowered plants.

To investigate this phenomenon, an initial study of 18 pairs of plants pollinated by leaf‐cutter bees, Megachile pacifica (Panzer), revealed that the yellow flowered plants produced only one‐half as much seed (P = 0.05) as plants with purple flowers. A subsequent more detailed study was then carried out in an attempt to determine the relative importance of flower color per se as a factor in alfalfa pollination and seed set.

Twenty pairs of yellow and purple flowered plants were studied in a spaced‐plant plot of ‘Ladak’ alfalfa which contained yellow flowered plants in a predominantly purple‐blue flowered population. Leaf‐cutters were used for pollination. Percent tripping was determined by observations of 100 florets on racemes taken at random from each plant. Other observations made were: number of florets (20 racemes), percent pods, seeds/pod, seed weight (g/200 seeds), and seed yield (g/plant). On the average, it was found that yellow flowered plants were tripped much less frequently (16% vs. 43%, P = 0.01), produced fewer seeds/pod (P = 0.01), lower percent pods (P = 0.01), and yielded half as much seed as purple flowered plants (P = 0.10).

It was concluded that if flower color per se is not the predominant factor responsible for the lower tripping and seed set on the yellow flowered plants, nevertheless it is associated with this phenomenon. This study indicates the need for more comprehensive studies to determine the cause(s) for the observed differential tripping and seed set of yellow flowered plants.
Mo and N Effects on Growth, Yield, and Mo Composition of Burley Tobacco1
Authors: Sims J. L. , Atkinson W. O. , Smitobol Chirtchart
Published: July 2010

Nicotiana tabacum L., cv. ‘Ky‐14’, was grown in field experiments on Maury silt loam soil (clayey, mixed, mesic; Typic, paleudult) to determine the influence of Mo and N nutrition on growth, yield, and Mo concentration of burley tobacco. Previous studies have shown that high rates of commercial fertilizers commonly applied in hurley tobacco production decreased soil pH, concentration of soil and plant Mo, and depressed dry matter accumulation during early growth stages. The present studies were designed to evaluate the use of Mo and NO‐3 sources of N fertilizer to increase early growth and final cured leaf yields.

In one experiment conducted during 2 years, N as KNO3, NH4NO3, or urea was applied at rates of O, 224, and 448 kg N/ha. Potassium in the form of K2SO4, and in amounts equivalent to the K in KNO3 was added to plots receiving NH4NO3 and urea. In a second experiment conducted during 1 year N as Ca(NO3)2 or urea was applied at rates of 280 kg N/ha. No K2S04 was applied. Rates of Mo as sodium molybdate were O, 0.22, and 0.44 kg Mo/ha in Experiment 1 and O, 0.22, 0.44, and 0.88 kg Mo/ha in Experiment 2.

In Experiment 1, dry matter accumulation during early growth was inversely related to rate of N and K fertilizer applied. Mo fertilization did not overcome the depressing effects of fertilizer on early growth, but a trend existed for both Mo and NO3‐ sources of N to improve early growth. Mo significantly increased yields of cured leaf. Significant N rate × Mo rate and N and K fertilizer treatment × Mo rate interactions occurred for cured leaf yields. Response to Mo occurred only at the 224 kg N rate, and Mo applied at the rate of 0.44 kg/ha increased yields about 900 kg/ha over plots unfertilized with Mo in the presence of KNO3. Average plant Mo concentration during early growth was doubled by adding Mo at the 0.44 kg/ha rate and halved by adding N at the 448 kg/ha rate. The critical concentration of Mo for dry matter accumulation during early growth appeared to be about 0.38 μ/g dry weight.

Results of Experiment 2 confirmed those of Experiment 1 regarding effects of NO3‐ sources and Mo fertilization. Additionally, Mn concentration in plants treated with Ca(NO3)2 was about half that of urea‐treated plants, and in urea‐treated plants Mn concentration was reduced by one‐half by Mo fertilization. Since Mn toxicity of tobacco is common in hurley production, these findings are of particular significance.
Abandoned Sugarcane Stubble as a Potential Source of Seedcane1
Authors: Broadhead Dempsey M.
Published: July 2010

Sparsity of buds on sugarcane stalks in vegetative propagation requires 1 ha of the current crop for seedcane to plant each 6 to 10 ha. In an attempt to obtain planting stock at less cost, second‐year abandoned ‘C. P. 36–111’ sugarcane (Saccharum sp.) stubble pieces were evaluated as a potential alternate source of seedcane. Two lines of mature stalk used as seed pieces (check) were compared with single stubble pieces spaced 15, 30, 60, and 90 cm; clumps of two‐piece stubble spaced 60 cm; and clumps of three‐piece stubble spaced 60 and 90 cm apart.

Yield of sugarcane grown from mature stalk seedcane was superior to that grown from single stubble pieces or from clumps of stubble. However, differences in yields from stalks and stubble pieces decreased in stubble crops. Single and multiple stubble pieces produced similar results. The Brix value was similar in juice from sugarcane grown from stalks and from stubble pieces.
Nitrogen Release from Isobutylidene Diurea: Soil pH and Fertilizer Particle Size Effects1
Authors: Hughes T. D.
Published: July 2010

Soil‐isobutylidene diurea (IBDU) mixtures were incubated to determine the effects of soil pH and IBDU particle size on N release patterns. Such information is needed for predicting rates and frequencies of application. All incubations were conducted at a temperature of 21 ± 0.5 C. and 28 ± 2% soil moisture. Evidence was obtained for excluding urea‐N concentrations from calculations of N recovery, thus all recoveries were based on concentrations of (NH+4 + NO−3)‐N.

Nitrogen release patterns from 0.7 to 0.8 mm IBDU particles in soil at initial pH's of 5.7, 6.8, and 7.7 were determined. After four weeks of incubation, the amount of N released was equivalent to one‐third of the IBDU‐N for soil at pH 5.7, however, lesser amounts were released in soil at pH's 6.8 and 7.7. Differences in N release were due to differences in NH+4‐N concentrations, whereas concentrations of NO−3‐N were not related to soil pH throughout the 10‐week incubation period. Thus, N release from IBDU was affected by soil pH shortly after fertitizer application, but this effect disappeared as soon as the NH+4 accumulation was exhausted by nitrifying organisms.

Fertilizer particle size had pronounced effects on N release in soil of initial pH's 5.7 and 7.4. Nitrogen recoveries of 75% after 10 weeks, 58% after 21 weeks, and 50% after 32 weeks were obtained for IBDU particle diameters of 0.6 to 0.7 mm, 1.0 to 1.2 mm, and 1.7 to 2.0 mm, respectively.
Yields and Sugar Content of Sugarbeets as Affected by Deficit High‐Frequency Irrigation1
Authors: Miller D. E. , Aarstad J. S.
Published: July 2010

Installation and operating costs of irrigation systems are related to system capacity and amount of water applied. If sprinkler systems can be designed for less than usual peak evapotranspiration rates, initial costs will be less. If less water is applied, operating expenses will decrease. Previous work indicated that sugarbeets can be grown satisfactorily under high‐frequency deficit irrigation (daily or more often at rates less than evapotranspiration) with soil water supplying part of the irrigation deficit. A field study was conducted, using solid‐set sprinklers, with the objective of determining the minimum amount of irrigation water that must be applied during peak use periods to avoid reduction in sugar yields. Treatments involved irrigation each morning at rates equivalent to various proportions of evaporation the previous day from a Class A Weather Bureau pan. The soil was near the upper limit of available water when the treatments were initiated.

In 1974 yields of roots and sugar were not significantly different at daily irrigation rates equivalent to 100, 75, or 50% of pan evaporation. In 1972 and 1973 sugar yields were decreased only by not irrigating from mid‐August to mid‐September, compared to daily irrigation at 90% pan evaporation. Total water used by the crop was decreased by deficit high‐frequency irrigation while yield of sugar per unit of water used increased. In 1974 sugar yields per unit of water used increased from 184 to 264 kg/ha/cm as irrigation rates decreased from 100 to 50% of pan evaporation.

This study indicates that with soils with adequate available waterholding capacity and crops that will tolerate deficit high‐frequency irrigation, systems can be designed for less capacity and total water application may be reduced. Soil water will be used to reduce the irrigation deficit.
Screening Soybeans for Tolerance to Metribuzin1
Authors: Barrentine W. L. , Edwards C. J. , Hartwig E. E.
Published: July 2010

Studies were initiated to develop a nutrient culture technique to select soybean [Glycine max (L.) Merr.] cultivars or breeding lines for tolerance to the herbicide metribuzin [4‐amino‐6‐tert‐butyl‐3‐(methylthio)‐as‐triazine‐5(4H) one]. Forty‐five soybean cultivars, representing determinate and indeterminate types commonly grown in the U.S., were screened in a modified Hoagland's nutrient culture containing 0.125 ppm metribuzin. Two cultivars, ‘CNS’ and ‘Wayne,’ and one breeding line, D66‐5566, were the most tolerant, showing only slight injury, whereas ‘Semmes’ and ‘Tracy’ were killed. Metribuzin caused severe injury to ‘Amsoy,’ ‘Chippewa 64,’ ‘Corsoy,’ ‘Clark 63,’ ‘Custer,’ ‘Delmar,’ ‘Arksoy,’ ‘Peking,’ ‘Dorman,’ and ‘Bragg.’ The remaining 30 cultivars were moderately injured. This technique will be useful in breeding programs to select for metribuzin tolerance.
Effect of Municipal Sewage Sludge on Rooting of Grass Cuttings1
Authors: Burns Robert E. , Boswell Fred C.
Published: July 2010

The availability of activated, digested, solid sewage sludge from municipalities at little or no cost suggests its possible use as a medium for sod production. Since most warm season sod is produced from vegetative material, and solid municipal sludge is available, the effect of this substrate on the rooting of grass cuttings should be evaluated. Due to the large difference found in quality of sludge from various disposal plants sludge from diverse sources should be compared. Cuttings of bermudagrass, centipedegrass, and zoysiagrass were rooted in activated, digested sludge from sewage plants serving an industrial area (I) and a residential area (R). The sludge from plant I had a much higher heavy metal content than that from plant R. The number of roots developed on bermudagrass cuttings rooted in I sludge was 80% of the cuttings rooted in R sludge and the total root length was 22% of those cuttings rooted in the R sludge. The difference between root production by centipedegrass cuttings in the two sludges was much greater than for bermudagrass. The effect of dilution of sludge with soil on root production was slight in comparison with the difference between soil and sludge. Both sludges were inferior to the soil controls as rooting media. The difference was greater when comparing the I sludge with soil than when comparing R sludge to soil. These data imply that the heavy metals in the I sludge may have retarded root formation on the grass cuttings since large differences in metal content of the two sludges were noted. Root primordia formation was reduced less than subsequent elongation of the roots.
Soil Water Uptake by Alfalfa1
Authors: Kohl R. A. , Kolar J. J.
Published: July 2010

Water uptake patterns of alfalfa (Medicago sativa L.) assist us in understanding proposed models governing plant water uptake. The data in this paper are presented to elucidate some details of passive water uptake from profiles with nonuniform soil water distributions. Soil water content under an alfalfa seed crop was monitored with a neutron moisture probe. Alfalfa roots withdraw soil water in the lower portion of the root zone (where soil matric potentials were between −7 and −10 bars), while the upper portion of the profile was above −2 bars. This indicates that for passive water uptake to occur, large water potential differences must exist between the root xylem and the soil in the upper, moist portion of the profile. Plant water potential measurements support passive uptake.
Performance of Maize Hybrids Grown in Conventional Row and Randomly Distributed Planting Patterns1
Authors: Mock J. J. , Heghin L. C.
Published: July 2010

Aerial seedings of maize (Zea mays L.) by farmers in the U.S. Corn Belt have been reported by the news media. However, there are no reports in the scientific literature of controlled experiments designed to study influences of random distributions of plants (the expected distributions with aerial seedings) on maize productivity.

Therefore, we conducted experiments in 1972 and 1973 to study effects of conventional row (spaced 102 cm apart) and randomly distributed planting patterns on growth and yield of two commercially available maize hybrids. In 1972, planting densities were 49,420 and 98,840 plants/ha, and in 1973 they were 39,536 and 79,072 plants/ha. Random planting patterns were obtained by casting heat‐killed field peas on the ground within a plot area and hand‐planting a maize kernel at each location of a pea. Both hybrids responded similarly to planting patterns each year. Percentage emergence, mature plant height, 50% pollen‐shed, 50% silk‐emergence, and number of ears/100 plants were not consistently influenced by planting pattern. Both years, however, significantly less grain was harvested from randomly planted than from row‐planted plots (i.e., −20.2 q/ha and −12.6 q/ha for 1972 and 1973, respectively), and response to increased plant densities was consistently smaller in random than in row planting patterns. Also, grain weight per plant was less (i.e., −25.0 g/plant) in randomly planted plots.
Nonionic Surfactant‐soil Interaction Effects on Barley Growth1
Authors: Valoras N. , Letey J. , Osborn J.
Published: July 2010

Research was conducted to integrate previously reported independent observations on surfactant adsorption, microbial degradation, uptake, and translocation, and on surfactant effects on plant growth in solution and soil cultures. Adsorption isotherms were measured for two nonionic surfactants and three soil materials. The shape of the adsorption isotherm was dependent upon both surfactant and soil properties. Barley (Hordeum vulgare L.) plants were grown in solution culture containing various concentrations of surfactant and in soil wet with surfactant solutions. Application of surfactant solution to soil reduced its toxicity to plants because of surfactant adsorption by the soil. The adsorption isotherm was used to calculate concentration of surfactant remaining in solution after application to soil. The effect of surfactant on plant growth was approximately the same in solution and soil cultures when the results were compared on the basis of solution concentration in the soil following adsorption. Less than 1% of the surfactant applied to soil was taken up and translocated in the barley plants. The difference between amount of a 14C‐labeled soil penetrant (an alkyl polyoxyethylene ether) applied and recovered in the soil and plant at the end of the experiment agreed with expected microbial degradation rates previously measured.
Sloughing Guard for Sequential Depth Soil Sampling1
Authors: Smith D. T. , Fickle J. S. , Abernathy J.
Published: July 2010

After field application of pesticides, soil may be sampled at several depths to ascertain persistance and movement in the profile. A simple, inexpensive device was designed to facilitate manual sampling and preserve sample integrity for sandy or loose surface soil. When samples are obtained from several depths, the guard prevents loose soil on the surface from sloughing into the hole and contaminating samples from subsequent depths.
Response of Soybeans in Maturity Groups V, VI, VII, and VIII to End‐trimming1
Authors: Boerma H. R. , Marchant W. H. , Parker M. B.
Published: July 2010

Accurate field plot technique is an important factor in soybean [Glycine max (L.) Merr.], cultivar and strain seed yield evaluation. Information on end effects in seed yield trials of soybeans grown in the southern region of the US is not available. The purposes of the present study were to determine the importance of these effects and the measures required to control them.

Three soybean cultivars each in maturity groups V, VI, VII, and VIII were end‐trimmed by removing 0.46 m from both ends of the harvest rows of plots at the early vegetative, beginning flowering, physiological maturity, and harvest maturity growth stages. Seed yield was determined on consecutive 0.3‐m sections from each end of the harvest rows and a 0.6‐m section from the middle of each row. The data indicated that removing 0.76 m from the end of plots at physiological maturity or a later stage should eliminate yield inflations.

In other tests 5, 4, 7, and 8 cultivars or strains in maturity groups V through VIII, respectively, were planted on 7 May and 20 June and the seed yield determined by both including and excluding the outermost 0.61 m from both ends of the 6.1‐m harvest rows. Significant changes in rank and in differences among genotypes were obtained with and without elimination of end effects. These differences existed both among and within maturity groups. Plant height affected yield inflation more than maturity date.
Yield Potential in a Dwarf Spring Wheat and the Effect of Carbon Dioxide Fertilization1
Authors: Fischer R. A. , Aguilar M. I.
Published: July 2010

Carbon dioxide fertilization provides a way of increasing crop photosynthesis and can be used to indicate when and to what extent crop photosynthesis limits grain yield and its components. A CO2 fertilization experiment was conducted using a dwarf spring wheat (Triticum aestivum L. ‘Yecora 70’) in each of three winter cropping cycles (1970‐73) in northwest Mexico. The wheat was grown in the field under irrigation and optimal agronomy. Small areas of crop (1 to 2 m2) were enclosed in transparent chambers ventilated with air enriched to approximately 750 ppm CO2; chambers ventilated with normal air and unenclosed areas of crop acted as controls. Fertilization was carried out in separate plots during each of four 1‐ month periods covering the crop cycle.

Fertilization with CO2 increased crop dry matter production. Grain yield was either unaffected or increased by up to 23% by extra CO2. Biggest yield increases came generally from CO2, in the 2nd and 3rd months and were associated with more spikes/m2 and grains/spikelet, hence more grains/m2. During the 4th month or grain filling period, kernel weight and grain yield were significantly increased in 1972, but clearly not in 1973. Results indicate greatest yield limitation by crop photosynthesis in the 2 months preceding grain filling, when grains/m2 is determined. They are discussed in relation to adjacent shading experiments with the same cultivar, to other CO2 fertilization studies with wheat and other crops, and to possible avenues for increasing yield potential.
Impact of Residual Mineral N in Soil on Grain Protein Yields of Winter Wheat and Corn1
Authors: Olson R. A. , Frank K. D. , Deibert E. J. , Dreier A. F. , Sander D. H. , Johnson V. A.
Published: July 2010

Fertilizer N has become a major cost input in the production of winter wheat (Triticum aestivum L.) and corn (Zea mays L.) with uncertainties remaining as to rates required for effecting optimum grain and protein yields without environmental pollution implications. For this reason investigations were conducted with the two crops to determine optimum rate of fertilizer N for grain and protein yields with varied levels of residual mineral N in the rooting profile of soil to 180 cm depth at planting. Fertilizer rates employed for wheat in 118 farmers' fields ranged from 0 to 67 kg N/ha by 22.5 kg increments broadcast in the spring and for corn in 17 farmers' fields from 0 to 225 kg/ha by 45 kg increments sidedressed at 30 to 45 cm growth stage.

Residual mineral N was found to exert major influence on grain protein percentage and protein yield of both crops within nominal rates of N fertilizer application. The magnitude of residuals varies with the soil environment and amount of prior fertilizer use on the soil. The data reveal that grain yield response of wheat to applied N is unlikely when soil residual mineral N exceeds 120 kg/ha and for irrigated corn around 240 kg/ha at the yield levels of approximately 25 to 30 quintals/ha of wheat and 85 to 90 quintals of corn obtained in these experiments. Maximum protein yield for wheat required an additional 50 to 60 kg N/ha and for corn 60 kg, economics of which can be ascertained only with knowledge of the unit nutritional value of the produce in relation to the unit cost of N applied.
Performance of Five Warm‐season Perennial Grasses Grown in Southern Mississippi
Authors: Brown W. E. , Spiers J. M. , Thurman C. W.
Published: July 2010

Increased interest in summer forage production in southern Mississippi prompted this study, comparing the performance of five perennial grasses. Plots of ‘Coastal,’‘Alicia,’ ‘Coastcross‐1,’ and Common bermudagrass (Cynodon dactylon L. Pers.) plus ‘Pensacola’ bahiagrass (Paspalum notatum Flugge) were harvested monthly during the 1973 growing season and at 2 and 4‐week intervals during 1974. Parameters measured were dry matter yield, digestible dry matter, and crude protein. Results show Alicia and Coastcross‐1 bermudagrass exhibited vigorous 1st‐year growth, but performance decreased during the 2nd year, especially of Alicia. Common also decreased in forage production in the 2nd year. Coastal maintained approximately the same level of growth both years, and bahiagrass increased in total yield during the second growing season.
Foam Application of Growth Retardants to Turfgrasses1
Authors: Aagesen G. J. , Elkins D. M.
Published: July 2010

Chemical growth retardants have been used on a limited scale to reduce mowing maintenance of turfgrasses. In recent years foam materials have served as carriers for pesticides and most recently for growth retardants. A foam carrier for retardants could offer the possible advantages of serving as an effective marker during application, reducing spray drift, and increasing growth retardant effectiveness. Four field studies were conducted in 1973 and 1974 at Carbondale, Ill. to compare foam application of growth retardants to conventional spray‐application on established turfgrasses. Three chemical growth retardants were tested on a ‘Park,’ Newport,' and ‘Delta’ blend of Kentucky bluegrass (Poa pratensis L.) and a pure stand of ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) with three commercially available foaming agents.

Growth retardant treatments resulted in lower grass height and decreased dry matter yields. In general, N‐phosphono methylamino‐diacetic acid (MON‐820) gave the best results with 3‐trifluromethyl‐sulfonamido‐p‐acetotoluidide (Sustar) intermediate and diethanolamine salt of 6‐hydroxy‐3‐(2H)‐pyridazinone (maleic hydrazide) least effective. Considerable losses in green color occurred with retardant treatments that gave the best growth retardation. The foam materials Fomex and Foamspray used as growth retardant carriers were equally effective as retardants applied by conventional spray methods. Thermofoam was not effective as a growth retardant carrier.

Growth retardants in foam carriers proved effective in reducing growth of turfgrasses. These findings show that foam application of retardants to roadbank vegetation merits investigation. Feasibility studies should also be conducted on the possibility of marketing a selected growth retardant with foam in an aerosol spray can or garden hose attachment as a home lawn care product.
Anhydrous Ammonia Applications During Fallow for Winter Wheat Production1
Authors: Smika D. E. , Grabouski P. H.
Published: July 2010

Anhydrous ammonia (NH3) was applied at the rate of 67 kg/ha on 20 July and 8 September the summer after harvest and 15 May, 30 May, 15 June, 30 June, 15 July, 30 July, and 15 August the following summer during two 14‐month fallow periods on Aridic Haplustoll and Torripsamment soils. The study was conducted to determine the ammonia application date during the 14‐month fallow period which produced the soil water‐soil NO3‐N distribution in the soil resulting in the maximum protein levels and grain yields of winter wheat (Triticum aestivum L.). Soil NO3‐N and soil water contents were determined to a 180 cm depth on each application date and at wheat seeding (15 September). In the Aridic Haplustoll soil, NH3 had to be applied in the summer after harvest (over 1 year before wheat seeding) for maximum NO3‐N accumulation in the soil between 60 and 120 cm which produced the highest protein grain (14.5%) and the highest yield (3,269 kg/ha). In the Torripsamment, NH3 applications between 15 May and 30 June the year of wheat planting produced highest protein grain (13.4%) and highest grain yields (2,688 kg/ha). However the optimum NH3 application date to produce the desired NO3‐N accumulation in the 60 to 120 or 150 cm soil depths in the Torripsamment was not determined in this study.
Xanthophyll Levels in Turfgrass Clippings1
Authors: Turgeon A. J. , Lester Gene
Published: July 2010

Xanthophylls include various plant pigments that are important in poultry diets for skin and yolk coloration. The recent use of turfgrass clippings as a source of xanthophyll for inclusion in poultry feed is a significant development since there are vast acreages of turf that could supply considerable amounts of clippings from routine mowing. The purpose of this study was to determine the xanthophyll levels in clippings from various turfgrass species and cultivars, and the effects of increasing nitrogen (N) fertilization on the xanthophyll concentration in the leaves.

Clippings from 20 cultivars of Kentucky bluegrass (Poa pratensis L.), 4 of perennial ryegrass (Lolium perenne L.) and ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) were analyzed for noneproxide xanthophyll (lutein). Levels ranges from 72 to 358 mg lutein per kg of clipping fresh weight depending upon species and cultivar. Increasing N fertilization resulted in significant but small lutein increases in Kentucky bluegrass clippings.
Downy Brome Control in Dryland Winter Wheat with Stubble‐mulch Fallow and Seeding Management1
Authors: Massee T. W.
Published: July 2010

Differences in downy brome (Bromus tectorum L.) control had been observed under field conditions of eastern Idaho when dates of stubble‐mulch tillage, final rod weeding, and winter wheat (Triticum aestivum L.) planting were varied. This field‐plot experiment on Tetonia silt loam (Pachic Cryoboroll‐coarse, silty, mixed) tested the degree of downy brome control obtained with three initial stubble‐mulch tillage dates, two final rod weeding dates, and three winter wheat planting dates.

Downy brome was best controlled with a combination of initial tilling early in the spring and a final rod weeding just before the late (15 September) wheat planting date. The early tillage killed downy brome before they produced seed. This also resulted in sufficient soil moisture retention in the seed zone for fall germination of other downy brome seeds, which were then killed by the final rod weeding just before the late wheat planting.

A reduction in natural downy brome emergence was observed at later fall dates. This was confirmed in a separate field‐plot experiment (Portneuf silt loam, Xerollic Calciorthid, coarse, silty, mixed) where downy brome seed was planted at several dates, and helped explain some of the benefits of the mentioned late rod weeding and planting treatment.

These procedures incorporating stubble‐mulch fallow are recommended, as normally practiced moldboard plowing creates an erosion hazard.
Modification of a Grassland Drill for Sward Interseeding1
Authors: Smith A. E. , Calvert G. V.
Published: July 2010

The commercially available pasture seeders have been found to be ineffective in stoney and topographically uneven swards, incapable of seeding in row spacing widths of less than 44 cm or too expensive for the average pasture renovation system. Introducing additional species into an existing sward has been recognized as beneficial for increasing forage production and quality and seasonal distribution of forage production. This publication describes a modification of a John‐Deere grassland drill. This modified pasture drill has been effective for interseeding ladino clover (Trifolium repens L. var. Ladino) into established stands of tall fescue (Festuca arundinacea Schreb) in the Piedmont area of Georgia.
Digestibility of Four Digitgrass Cultivars under Different Harvest Frequencies1
Authors: Sleper D. A. , Mott G. O.
Published: July 2010

Lack of good forage quality is one of the factors limiting animal production on digitgrass pastures. The purpose of this investigation was to examine quality differences in digitgrass. Three digitgrass cultivars and an interspecific hybrid were used to determine cultivar differences and duration of regrowth period that would provide maximum in vitro digestibility for the summer. Forage was harvested at 14, 28, and 42‐day intervals. Forage harvested every 14 days had significantly higher digestibility than that harvested at 28 and 42‐day intervals. Cultivars also differed significantly in digestibility. ‘Transvala’ (Digitaria decumbens Stent.) had the highest in vitro digestibility when harvested at 14‐day intervals (70%) whereas an experimental interspecific hybrid X50‐1 (parents were Digitaria milanjiana Strent, and Digitaria Pentzii Stent.) had the highest digestibility of all cultivars at the 28 and 42‐day regrowth intervals (68 and 61%, respectively). Within the 14‐day harvest frequency, ‘Pangola’ (Digitaria decumbens Stent.) decreased in digestibility the most and ‘Slenderstem’ (Digitaria pentzii Stent.) the least as the season progressed. Management systems and breeding objectives that allow for improved quality in digitgrass should be utilized.