bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water and Air Changes in Grapefruit, Corn, and Cotton Leaves with Maturation1
Authors: Allen William A. , Gausman Harold W. , Richardson Arthur J. , Cardenas Ruben 
Published: July 2010

AbstractRecent progress in remote sensing of agricultural areas from aircraft and spacecraft has motivated new research in the basic understanding of the interaction of light with plant leaves. Many plant leaves can be simulated by a transparent plate model with rough plane‐parallel surfaces. A plant leaf can be specified in this model by two optical parameters associated with an imaginary index of refraction and two parameters that represent the geometrical configuration of the internal leaf structure. The model leads to determination of water and air in a leaf by non‐destructive procedures. Previous work that reported on maturation of cotton leaves grown hydroponically in a growth chamber has been extended to leaves of potted grapefruit seedlings, field‐grown corn, and field‐grown cotton plants. Significant differences are observed between the measured water in a leaf and the equivalent water thickness (EWT) calculated from spectrophotometric measurements. The EWT is about 15% greater than the thickness of water that can be removed from the leaf by oven drying at 68 C for 72 hours. Measures of the intercellular air spaces in the leaves are in general agreement with previous results except that the corn leaves are not as compact as expected.
Evaluation of Selected Clones of Phalaris arundinacea II. Indole Alkaloid Derivatives1
Authors: Barnes R. F. , Simons A. B. , Marten G. C. 
Published: July 2010

AbstractIndole alkaloid derivatives have been reported in reed canarygrass (Phalaris arundinacea L.). We measured the contents of three alkaloids in two palatable and two unpalatable clones of reed canarygrass to study the relationship between alkaloids and palatability. The palatability ratings had been previously determined in cafeteria grazing trials with sheep. Chopped frozen forage from four harvests of each clone was available from previous in vivo digestion and intake trials conducted in 1962 and 1963. Samples from the initial growth and first regrowth of 1962 and first and second regrowth of 1963 were analyzed for gramine (3‐dimethylaminomethylindole), 5 methoxy‐N,N‐dimethyltryptamine (5‐MeO‐DMT), and N,N.dimethyltryptamine (DMT). The assay procedure involved ascending paper chromatography followed by elution and spectrophotometry for quantitative estimation of each compound. The palatable clones contained up to 0.1% gramine, but no DMT. Conversely, the unpalatable clones contained up to 0.02% DMT, but no gramine. All clones contained 5‐MeO‐DMT; however, the palatable clones had 0.01% or less, compared to 0.07% in the unpalatable clones. We found the lowest concentrations of total alkaloids in the initial growth forage and the highest concentrations in the first regrowth of 1963.
Nitrogen Release from Sulfur‐Coated Urea, as Affected by Coating Weight, Placement and Temperature1
Authors: Allen S. E. , Hunt C. M. , Terman G. L. 
Published: July 2010

AbstractGreenhouse and laboratory studies were conducted to measure the factors controlling release of N from sulfurcoated urea (SCU). Results of two greenhouse pot experiments with common bermudagrass (Cynodon dactylon) and a third with uncropped soil in controlled environment regimes showed that the rate of dissolution of SCU increased greatly with higher temperatures of cropping or incubation. Dissolution rates of SCU granules were decreased by heavier coating with S, by inclusion of 0.5% coal tar oil microbicide in the coating, and by surface application, as compared to mixing with the soil. Satisfactorily coated urea (SCU) or split applications of uncoated ammonium nitrate (AN) or urea both resulted in more uniform distribution of forage production and N uptake than did a single application of urea or AN at time of seeding. Greater yields of forage were obtained from single applications of some SCU products than from urea or AN. Apparent volatilization losses of surface‐applied urea were severe, particularly at higher growth or incubation temepratures. Losses of N were reduced, but not entirely eliminated by S‐coating.
Germination of Caryopses of Annual Grasses in Simulated Litter1
Authors: Young James A. , Evans Raymond A. , Kay Burgess L. 
Published: July 2010

AbstractA technique was developed for germinating grass caryopses in simulated litter, without the base of the caryopses in contact with a liquid moisture‐supplying substrate. Litter germination of five annual species of bromegrass and medusahead differed markedly in response to temperature from 10 to 25 C, compared to germination of the same species in petri dishes. The species also differed in their rates of root elongation and root persistence under repeated drying cycles at incubation temperatures from 10 to 25 C. The differences in litter germination among the annual grasses investigated may be the basis for dominance of one species over another under specific temperature regimes.
Response of Plant Water Potential to the Irrigated Environment of Southern Idaho1
Authors: Cary J. W. , Wright J. L. 
Published: July 2010

AbstractLaboratory studies have shown that plant water potential affects a number of key processes involved in growth, but there has been almost no information on what levels of water potential occur under irrigated conditions in the field. Before assessing the practical implication of laboratory results on soil and crop management, this type of information must be available. Consequently, plant water potential in irrigated crops of Zea mays, Triticum aestivum, Hordeum vulgaris, Phaseolus vulgaris, Pisum sativum, Solanum tuberosum, Beta vulgaris, and Medicago sativa, L. was measured throughout the growing season in southern Idaho. Soil moisture conditions and potential evapotranspiration were monitored. Daily changes in plant water potential varied from less than 5 bars to more than 20 bars, while random sampling of supposedly homogeneous sets of plants showed an average variation of about 2 bars. Changes due to differences in soil moisture were also detected, even though the soil moisture potential was kept high enough for near‐optimum crop production. Though the crops differed widely in their response to changes in environment, the plant water potential was strongly affected by microclimatic conditions. Day‐to‐day changes in plant water potential generally correlated more closely with changes in potential evapotranspiration than with changes in soil moisture content. Many of the daily changes observed in the plants remain unexplained, however. In general, the average water potential levels of all the field‐grown plants were lower than levels reported from growth chamber studies. Potentials seldom rose above —8 bars and were never observed above —5 bars.
Reliability of Salinity Sensors for the Management of Soil Salinity1
Authors: Oster J. D. , Willardson L. S. 
Published: July 2010

AbstractLaboratory‐constructed and commercial salinity sensors were evaluated for stability of calibration and accuracy of measurement of soil salinity. Of the commercial sensors 85% were stable and performed satisfactorily for at least 1.5 years with an estimated accuracy of ± 0.6 mmho cm‐1. Laboratory‐constructed sensors were accurate to ± 1 mmho cm‐1. Commercial sensors were used to monitor soil salinity in a field in the Imperial Valley, demonstrating their value for salinity control. The salinity data revealed differences in water infiltration caused by surface topography and by the disturbance of soil during the installation of the sensor.
Iron and Zinc Response of Chlorotic Rice Grown on Calcareous Soils1
Authors: Westfall D. G. , Anderson W. B. , Hodges R.J. 
Published: July 2010

AbstractIron and Zn source and rate experiments were carried out in the field on soils where rice (Oryza sativa L.) grain yields had been reduced drastically in previous years by seedling chlorosis.Soils where seedling chlorosis occurred were higher in pH, HCO3 and Ca content and lower in Fe and Zn than adjacent soils where normal growth occurred. Iron sulfate, alone or in combination with ZnSO4, was the most effective in correcting seedling chlorosis. A maximum yield increase of over 2,100 kg/ha was obtained with the application of 100 kg/ha of Fe (from Fe2(SO4)3). Organic sources of Fe and Zn were less effective in correcting needling chlorosis and producing yield increases.
Potassium Effects on Regrowth of Alfalfa (Medicago sativa L.)1
Authors: Kimbrough E. L. , Blaser R. E. , Wolf D. D. 
Published: July 2010

AbstractField experiments were conducted to investigate the relationship of K in alfalfa (Medicago sativa L.) plant tissues on dry‐matter yields and other growth characteristics at different stages of maturity.Yield increases were highly correlated with increases in percent K in alfalfa leaves or herbage (leaves and stems). The correlations of percent K in tissue with the dry‐matter yields were highest when sampling in a bud stage of growth, and declined with advancing maturities with later samplings. Sampling for K at the time of harvesting underestimated the percent K needed for high yields; herbage that had accumulated for 18 days (bud stage) averaged 143% more in K than at 39 days (full bloom).The percent K in leaves and herbage was augmented by K fertilization, but the herbage was higher than leaves in K. The percent K in herbage declined sharply with advancing maturity; this did not occur for leaf tissue.Yields and LAI's increased faster with liberal than with low K. The faster regrowth rates with high as compared with low K may make it possible to shorten cutting intervals, and make an additional cutting during the season. During advanced maturities after 32 days of growth, the LAI's generally stabilized or declined because of leaf losses.Factors that influence the percent K in tissue should be considered when associating K composition with yields of alfalfa.
Relations Between Fe in Irrigation Water and Leaf Quality of Cigar Wrapper Tobacco1
Authors: Rhoads F. M. 
Published: July 2010

AbstractDamage, appearing to result from irrigation water, reduced the value of cigar wrapper tobacco (Nicotiana tabacum L.) from about $4.00 per pound to 0.25 in 1969. Dark leaf tips and dark spots over the entire leaf rendered damaged leaves unfit for wrapper use. Leaf analysis indicated that Fe and Mn were associated with the dark coloration.A study was made in 1970 to determine the effect of Fe in irrigation water on quality of cured wrapper tobacco leaves and to find a potential source of Fe contamination of irrigation ponds. Two forms of Fe were added to irrigation water applied to field plots, and Fe content of leaves, leaf quality, and leaf tensile strength were used to evaluate the effects. Soil and organic material were collected from a shallow area of a “problem” pond, after it had been drained, for use in laboratory studies.Damaged tobacco, similar to that observed in commercial fields, was produced in field plots in 1970 when Fe was added to the irrigation water. Laboratory incubation studies showed that pond sediments were a potential source of Fe buildup in irrigation water. Leaf strength decreased with increasing content of Fe in the tissue. A visible coating was produced on green leaves in the greenhouse when 5 and 10 ppm Fe in water were sprayed on the plants.
Stabilization of Newly Formed Soil Aggregates1
Authors: Arya L. M. , Blake G. R. 
Published: July 2010

AbstractThe stabilization of newly formed soil aggregates was observed. Stabilization was postulated from previous research to be time dependent. Three kinds of newly formed aggregates were collected, aged at constant water content, and tested for changes in relative stability in water at frequent intervals after formation.Stability of 3‐ to 5‐mm diameter aggregates collected immediately after plow‐shearing on four soil types increased with time after plowing when water content was held constant. The rate of increase was high during initial aging times and decreased as aging progressed. Increases of about 0.17 for sandy soils and about 0.24 for finer‐textured soils were observed in 72 hours of aging. For all soils, stability increase after about 10 to 12 hours was small.Earthworm casts were simulated by extruding kneaded, moist soil through a sieve with 2‐mm round holes. Extrusions aged at four water contents showed considerable increases in relative stability in the 24‐hour period following formation. Stabilities determined shortly after extrusion varied with water content of the extrusions. The largest change in stability was from 0.68 to 0.98 at a water content of 0.36 g/g.Aggregates were also prepared by placing water drops on dry soil powder and collecting the individual coalesced portions. These aggregates were aged at two water contents. Initially, stabilities were near 0 but attained values ranging from 0.14 to 0.31 in about 120 hours. Stability differences due to water content were inconclusive.These facts raise important questions regarding timing of tillage operations following plowing. Soils in humid climates with a tendency to weakly developed aggregates may have better tilth if further tillage is delayed a few hours. The data suggest that an intense rain soon after plowing will puddle the soil to a greater extent than if it is delayed a few hours.
Calcium‐stimulated 32P Accumulation by Corn Roots1
Authors: Miller Raymond J. , Peverly John H. , Koeppe D. E. 
Published: July 2010

AbstractThe polyvalent cation‐stimulated uptake of phosphate (P) by plant roots has been acknowledged for some time. However, the mechanism of this stimulation and the site of activity have been poorly defined. Most evidence indicates that mitochondria are involved with ion uptake, thus suggesting the possibility that the polyvalent cation stimulation of P uptake by plant roots might be associated with mitochondria. This paper correlates the P accumulation (32P) by isolated corn (Zea mays L.) shoot mitochondria and intact corn roots in the presence of various known inhibitors of electron transport or phosphorylation. In both intact roots and isolated mitochondria, Ca+2 treatment stimulated the uptake of P when compared to either Mg+2 treatment or control treatment. But a ratio of 4 mM Ca:l mM Mg produced optimal stimulation of P uptake when compared to other ratios of these cations. Oligomycin, azide, and 2,4‐dinitrophenol reduced the uptake of P by whole roots, but only 2,4‐dinitrophenol abolished the Ca+2 preferential stimulation of P uptake. These results are compared to similar studies with isolated mitochondria and suggest that the accumulation of P by intact corn roots is at least partially controlled by mitochondria and that the Ca+2 stimulation of P uptake by roots may be explained in terms of mitochondrial reactions.
Diurnal Variation in Nitrogenous Constituents of Alfalfa (Medicago sativa L.)1
Authors: Youngberg H. W. , Holt D. A. , Lechtenberg V. L. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) was sampled eight times daily for 3 days during a third growth period in order to detect diurnal changes in concentrations of various classes of nitrogenous constituents. The implications of these changes with regard to N metabolism were considered.Total N was determined by predigesting forage samples with salicylic‐sulfuric acid and assaying with the Nessler reagent. Total water‐soluble N was determined by performing the same procedure on aqueous extracts of the tissue. Nitrate N was assayed by the phenol‐disulfonic acid procedure. Ninhydrin was used to determine amino N. Potassium concentration in an acid digest of tissue was measured spectrophotometrically. Analyses were performed on leaflets and on stems and petioles.The percentages of total N, water‐soluble N, amino N, and K in alfalfa leaves and stems were highest between 3 and 6 AM and declined through the light period during 3 days of frequent sampling in the field. Nitrate N in alfalfa stems followed a similar trend, but there was no diurnal change in nitrate concentration in leaves.Nitrogen compounds are diluted during each light period by the considerable amount of nonstructural carbohydrate synthesized. This probably accounts for the observed decline in percentage of nitrogenous constituents.
Effect of Trampling by Cattle on Bluegrass Yield and Soil Compaction of a Meadowville Loam1
Authors: Bryant H. T. , Blaser R. E. , Peterson J. R. 
Published: July 2010

AbstractThe objective of this research was to evaluate both the tolerance of a Meadowville loam soil (Typic Hapludult; fine‐loamy, mixed mesic) and bluegrass (Poa pratensis L.) grown in this soil to three levels of trampling by cattle. The protective effect of 2.5 cm, 7.6 cm, and 20.3 cm of bluegrass at tune of trampling, as measured by the resistance of the soil to penetration, was studied. The trampling pressures, repeated four times during the year, were 0, 60, and 120 trips/cow. The pressure, kg/cm2, required for the point of the penetrometer to penetrate the soil was significantly different among trampling pressures for 1, 3, and 4 trampling dates. As trampling intensity increased, maximum resistance to the penetrometer was encountered closer to the soil surface. The height of forage at trampling had no significant affect on either the force required to penetrate the soil or depth of soil at which maximum resistance to penetration was encountered.Yields of herbage from plots clipped from 20.3 cm to 7.6 cm prior to trampling and after trampling to 2.5 cm were compared with yields from plots clipped prior to and after trampling from 20.3 cm to 2.5 cm, respectively. Yields from plots clipped at 2.5 cm prior to trampling compared to plots not clipped prior to trampling were slightly lower. Increasing trampling pressure had a significantly adverse affect on forage yield for tramplings in June and September.
Establishment, Hay Yield, and Persistence of Two Sainfoin Growth Types Seeded Alone and With Low‐Growing Grasses and Legumes1
Authors: Cooper Clee S. 
Published: July 2010

Abstract‘Eski’ sainfoin (Onobrychis viciaefolia Scop.), a “one‐cut” cultivar, and ‘Remont’ sainfoin, a rapid regrowth “two‐cut” cultivar, were evaluated for hay production in pure stands and in mixtures with low‐growing grasses and legumes on irrigated land over a 4‐year period. Measurements were made of seedling establishment, yield, and persistence. Yields of Remont were slightly greater than those of Eski for the 4‐year period. The difference in yield was primarily due to greater seeding year yields of Remont. Within a given year, Eski yielded more at the first harvest and less at the second harvest than Remont. Yields of both cultivars decreased in the fourth year due to a partial loss of stand.Sainfoin mixtures containing either birdsfoot trefoil (Lotus corniculatus L.) or black medic (Medicago lupulina L.) were most productive and those containing Ladino or common white clover (Trifolium repens L.) least productive. The latter species were more competitive with sainfoin, particularly Eski, because of rapid regrowth following clipping.Pure stands of both sainfoins were heavily invaded by dandelion (Taraxacum officinale Weber) in 1971, and mixtures of sainfoin with either birdsfoot trefoil, black medic, or common white clover were invaded to a lesser degree. Sainfoin cultivars grown with Ladino clover, Kentucky bluegrass (Poa pratensis L.) or red fescue (Festuca rubra L.) were not invaded by dandelion. The relative merits of the two sainfoin types are discussed.
Wheat Response to Short‐term Heat Stress and to Soil Oxygen Stress at Three Stages of Growth1
Authors: Sojka Robert E. , Joseph H. A. , Stolzy L. H. 
Published: July 2010

AbstractWheat (Triticum aestivum L.) was grown under controlled environmental conditions for 47 days in two experiments to examine responses to low aeration beginning at various stages of growth, and to determine whether an interaction between temperature and soil aeration status is measurable in wheat. In both experiments oxygen was eliminated from the soil beginning at three different times in the growth cycle. In the second experiment the wheat was subjected to 36 hours of heat stress (42 C) on the 23rd day of growth.There was a trend toward greater water use with low soil aeration. The root:shoot ratio was significantly decreased by poor aeration in the experiment without heat treatment; all three low‐aeration treatments exhibit essentially the same root:shoot ratio despite different treatment starting times, which indicates that the duration of the low oxygen treatment necessary to alter the root:shoot ratio is relatively short. Interaction of low aeration and heat stress sharply reduces root weight and increases water use per dry weight plant tissue produced, with the effect generally more dramatic with low aeration for longer periods of time. After only a brief period of treatment all characteristics measured, except root:shoot ratio, were significantly affected by heat stress. The effects are partially interpreted in terms of increased respiration rate, leading to degradation of cytoplasm as a result of induced oxygen scarcity.
Effect of Inoculum Size on Nodulation of Glycine max (L.) Merril, Variety Ford1
Authors: Weaver R. W. , Frederick L. R. 
Published: July 2010

AbstractA criterion for determining adequacy of inoculation of Glycine max by Rhizobium japonicum is needed for testing of commercial inoculants and for determining adequacy of nodulation. This study was undertaken to determine the inoculum level needed for maximum nitrogen fixation of Glycine max and to find a qualitative nodulation pattern that would be useful in recognizing good nodulation. To accomplish this end, soybeans were inoculated and grown in pots containing sand or soil in the greenhouse. Inoculation levels up to 2.4 ✕ 105 and 1.4 ✕ 107 Rhizobium japonicum cells per seed were used for soil‐ and sand‐grown plants respectively. Taproot nodulation was still increasing at the highest inoculum level in soil and sand, but lateral root nodulation had leveled off. Maximum total nitrogen fixed in plant tops was achieved at inoculation levels of 2 ✕ 103 and 1 ✕ 105 cells per seed for soil‐ and sand‐grown plants, respectively. At these inoculation levels at least four taproot nodules were formed. Results suggest that taproot nodulation of soybeans is a qualitative characteristic that may be useful in determining the adequacy of nodulation and may indicate abundance of rhizobia for a soybean variety.
Growth Analysis of Two Sainfoin (Onobrychis viciaefolia Scop.) Growth Types1
Authors: Cooper C. S. 
Published: July 2010

AbstractAdaptation of sainfoin (Onobrychis viciaefolia Scop.) to dryland may be related to differences in growth habit that permit the most efficient use of available moisture and incident radiation during the active growing season. This study was conducted to quantitatively analyze growth of ‘Remont,’ a “two‐cut” type cultivar, and ‘Eski,’ a “onecut” type cultivar, in relation to adaptation to dryland or to areas with limited irrigation water. Growth was studied during three periods in the spring of 1971. Yields of Remont were significantly higher than those of Eski when sampled on May 12, but because of a greater relative growth rate (RGR, g/g/wk), Eski surpassed Remont in yield when sampled on June 21. The greater RGR of Eski was associated with a significantly greater leaf area ratio (LAR, dm2/g). The LAR of both species decreased with advancing maturity as a result of increasing stemleaf ratio. Net assimilation rate (g/dm2/wk) of these two cultivars was not significantly different. Crop growth rate (CGR, g/m2/da) increased as the season advanced and appeared to be greatest for Eski. Both species produced the majority of their leaves early with maximum leaf area index occurring on or before June 8. Specific leaf weight (cm3/g) of cultivars was similar at the first three sampling dates, but was significantly greater for Remont at the last sampling date. The data indicate that a late‐maturing “one‐cut” type sainfoin would most efficiently utilize soil moisture and incident radiation in areas where soil moisture is limiting after July 1.