bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses of Stomata and Water, Osmotic, and Turgor Potentials of Jojoba to Water and Salt Stress1
Authors: Adams J. A. , Bingham F. T. , Kaufmann M. R. , Hoffman G. J. , Yermanos D. M. 
Published: July 2010

AbstractJo]oba (Simmondsia chinensis (Link) Schneider) is desert shrub which can provide a much needed substitute for sperm whale oil. Because of the absence of soil‐plant‐water data for jojoba and the limited amount of such information for desert plants in general, selected plants were water‐ and salt‐stressed in greenhouse soil and sand culture experiments. Responses of leaf water, osmotic, and turgor potentials to stress and associated stomatal behavior were studied.Leaf water potentials of well watered jojoba plants (measured with thermocouple psychrometers) averaged —20 bars in the daytime and were generally below —10 bars at night, very low in comparison to most mesophytic plants. The recovery of plants which were water stressed to leaf water potentials below —50 bars (soil water potentials below —40 bars) indicates great drought tolerance. Turgor potential decreased linearly with decreasing leaf water potential, showing a lack of osmotic adjustment as leaf water potentials fall below about —30 bars. Turgot potential reached zero at a leaf water potential of about —35 bars, and dropped as low as —10 bars under the most severe water stress without wilting of mature leaves. Plants in the salinity experiment showed osmotic adjustment down to a root medium osmotic potential of —9 bars.Values of leaf conductance decreased markedly only at very low xylem pressure potentials (pressure chamber measurements) and soil water potentials (—40 bars and —20 bars, respectively), corresponding to about the same values at which turgor potential reached zero. Stomatal closure was continuous with increasing water stress, rather than occurring abruptly at a threshold. There was no significant decrease in leaf conductance at root medium osmotic potentials as low as —9 bars in the salinity experiment.Conductances of well watered plants to water vapor on lower leaf surfaces were typically similar or greater in value than those of upper leaf surfaces, whereas plants under water stress showed significantly higher conductances on their upper leaf surfaces rather than lower leaf surfaces.Leaf xylem pressure potentials decreased with increasing transpiration rate under non‐limiting soil water conditions and decreased below values predicted for well watered plants at the same transpiration rate as soil water potentials decreased. Thus it was possible to make an estimate of edaphic limitations of water absorption based on leaf xylem pressure potentials despite variation in the pressure potentials in response to microclimatic changes.
Radiation and Energy Balance of Sprinkler and Trickle Irrigated Fields1
Authors: Ben‐Asher J. , Fuchs M. , Goldberg D. 
Published: July 2010

AbstractWater conservation claims in favor of trickle irrigation are poorly documented. The radiation and energy balance of tomatoes (Solanum lycopersicum L. ‘Arava S‐5’) grown on sand dune soil and on bare soil irrigated by sprinkling and trickling were compared. Under trickle irrigation, the average ratio of five energy balance measurements of evapotranspiration over evaporation pan (Class A) was 0.3, compared with 0.60 obtained under sprinkler irrigation. The comparison of radiation balance over the trickle and sprinkler irrigated plots indicates that the increased radiant heat loss and albedo from the dry portion of the trickle irrigated plot decreases the available evaporative energy at ground level. The smaller radiant heat load combines with the resistance of the dry soil to water flux to reduce the evaporation of the trickle irrigated plot.
Chemical Composition and Potential Uses of Annual Canarygrass1
Authors: Robinson Robert G. 
Published: July 2010

AbstractAnnual canarygrass (Phalaris canariensis L.) is used for birdfeed, but this research was undertaken to study its chemical composition and evaluate its potential for food or industrial uses. Caryopses and hulls were analyzed for elemental, amino acid, ash, oil, and fiber composition. Roots, stems, and florets were analyzed for elemental composition. Factors to convert N percentage to protein percentage were calculated by dividing 100 by the percentage N in the total amino acids of the caryopses, hulls, or florets. Mature plants from research plots in southeastern and northwestern Minnesota were analyzed by standard methods. Soils were Typic Hapludolls and Vertic Haplaquolls. Caryopses of ‘Alden’, ‘Heracles’, ‘M82’, ‘M89’, ‘M139’ and ‘P.I. 170622 Turkey’ were not markedly different in chemical composition. Canarygrass and oat (Avena saliva L.) differed significantly in elemental composition of florets but not in stem or root composition. Data averaged from 3 years and three locations showed that canarygrass Caryopses had a total amino acid concentration of 19.25% and a N to protein conversion factor of 6.71. The high amino acid concentration placed canarygrass above most grain crops and in a group with many pulse and oilseed crops. Its N‐to‐protein conversion factor was the highest reported for any crop. Canarygrass caryopses had higher concentrations of all eight essential amino acids than did those reported for wheat (Triticum aestivum L.) or corn (Zea mays L.) caryopses. Canarygrass hulls contained 20% ash. Annual canarygrass is a potential food grain crop.
Differential Response of Soybean Varieties to Soil Cadmium1
Authors: Boggess Sam F. , Willavize Susan , Koeppe D. E. 
Published: July 2010

AbstractOf the trace elements being redistributed by our present‐day society, Cd presents probably the greatest potential as a toxic agent in applications to soils. Numerous studies have indicated that various plant species accumulate differing toxic amounts of Cd, and that the toxic symptoms are exhibited differently. Studies to assess the possibility that different varieties of one plant species may exhibit a range of Cd uptake and/or susceptibility have not been conducted in a comprehensive manner. This paper presents the results of a comprehensive survey of the Cd uptake and effect by a number of the prominent soybean [Glycine max (L.) Merrill] varieties grown on several CdCI2 or sewage sludge‐amended soils in the glasshouse. In all varieties, Cd toxicity symptoms appeared as a continuum from slight effects observed as a red, red‐brown, or purple coloration at the junction of the leaf blade and petiole, to severe leaf curling and extensive reddening of the leaf veins, chlorosis, and finally a brittle condition followed by abscission of the leaves. All varieties showed increased shoot Cd concentration and decreased dry weight in response to soil CdCl2, but varietal differences in the severity of these Cd effects were observed. To quantify these differences in plant response to soil CdCI2, indices based on the severity of visual symptoms, dry weight reduction, and shoot Cd concentration were used to rank the varieties according to Cd susceptibility. As all three rankings were significantly correlated, a composite susceptibility index based on all three criteria could be used to describe the response of each variety to Cd. Susceptibility index rankings of varieties grown on three different CdCl2‐amended soils were found to correlate with each other and with relative Cd concentrations of varieties grown on sewage sludge‐amended soil. Soybean maturity groupings were not correlated with visual symptoms, dry weight reduction, or shoot Cd concentration. The data suggest that of the soybean varieties tested for Cd susceptibility on CdCl2‐amended soils that Dunfield, Harosoy, Arksoy, Dare, Flambeau, and Scioto were generally the most susceptible while Clark, Mandarin, Mukden, Jackson, and Lee were consistently ranked as less susceptible.
Growth and Yield of Jojoba Plants in Native Stands Using Runoff‐Collecting Microcatchments1
Authors: Ehrler W. L. , Fink D. H. , Mitchell S. T. 
Published: July 2010

AbstractWater‐harvesting techniques were applied to a waterstressed native stand of jojoba (Simmondsia chinensis (Link) Schneider) near Phoenix, Arizona, to evaluate this method of supplementing the normally scant rainfall for increasing seed yield and to gain insight into the comsumptive water requirements of the plant. Thirty small, indigenous, female bushes were selected and randomly divided into three treatments: T0, no water‐harvesting catchments; T1, cleared, smoothed, and rolled 20‐m2 catchments; and T2, like T1, but with the catchment treated with a water‐repellant coating. Data collected were: rainfall, runoff, soil moisture, relative leaf water content, plant volume, and seed yield. The 4‐year average of precipitation plus runoff to plants during the critical growth‐yield period of October through June was: T0, 154 mm; T1, 435 mm; and T2, 876 mm. The plant volume increase averaged 43, 44 and 237% for T0, T1 and T2, respectively. Seed yield in 1974, the first year, averaged 0.5, 8, and 23 g/plant for treatments T0, T1 and T2, respectively. Frost injury destroyed the flowers in 1975 and 1976, but in 1977 yields increased to 27, 76, and 208 g/plant for the respective treatments. Maximum yield was 514 g/plant. These preliminary results on this slow‐growing shrub suggest that its consumptive water requirement exceeds 450 mm, and may be as great as 900 mm. Water harvesting is one way of supplying this required water,
Interactions of Early‐ and Late‐planted Winter Wheat with Their Environment1
Authors: Thill D. C. , Witters R. E. , Papendick R. I. 
Published: July 2010

AbstractIn eastern Washington, early fall‐planted wheat (Triticum aestivum L.) has a greater yield potential than late‐planted wheat, and the additional fall growth of the early‐planted wheat improves erosion control after fallow. The purpose of this study was to investigate plant‐environmental interactions of early‐ and late‐planted wheat in the field and to determine morphological, physiological, and environmental interactions that contribute to the greater yield potential of the early‐planted winter wheat under disease‐free conditions.Plant growth and development was evaluated on ‘Nugaines’ soft, white winter wheat planted in a Palouse fine silty soil (mesic pachic ultic Haploxerolls) in early September (EPW) and early October (LPW) in eastern Washington. Recommended rates of fertilizer for maximum yields were used and the wheat was sprayed with a fungicide in early spring to control Cercosporella foot rot. Canopy apparent photosynthesis and transpiration were measured throughout each day in the field by infraed gas analysis using an open system equipment design. Beginning in early spring, leaf area, number of tillers and heads, and plant dry weight were determined at 1‐ to 2‐week intervals. From these determinations, leaf area index and leaf area duration were calculated. In addition, leaf water potential and soil moisture depletion were measured throughout the growing season by use of a Scholander‐type pressure chamber and neutron moisture meter, respectively.The EPW produced more grain field, tillers m−2, heads m−2, and kernal weight than the LPW, but significantly fewer kernels per head. Growth analysis indicated that EPW and the LPW plants maintained nearly equivalent internal plant water potentials throughout the growing season. Aparently, the EPW had superior yield potential because its root system was capable of extracting sufficient soil water during the spring and summer to maintain a plant water status that supported CO2 fixation per unit area of leaf equivalent to that of LPW. Thus, the maintenance of greater leaf area by the EPW during the grain‐filling period provided the basis for greater net assimilation and grain yield.
Molybdenum Availability as Predicted from Selected Soil Chemical Properties1
Authors: Karimian N. , Cox F. R. 
Published: July 2010

AbstractMolybdenum deficiencies have been noted in the southeastern United States but there is limited information on plant and available soil Mo levels. Also, there has been little research directed toward interpreting these levels. Samples of 20 Coastal Plain and Piedmont soils were extracted with acid ammonium oxalate solution (Grigg Mo) and with anion exchange resin (resin Mo). Grigg Mo levels ranged from 17 to 183 μg/kg and resin from 2.5 to 11.1 μg/kg. Growth and uptake of Mo was determined on Early Snowball cauliflower (Brassica olera cea botrytis L.) grown in the soils which had been treated with none or 1 μg Mo/g soil. Soils from the Piedmont region without Mo produced cauliflower plants with Mo deficiency symptoms. Applied Mo increased dry weight and Mo concentration of cauliflower grown in most of the soils. No correlation was found, however, between response or plant Mo concentration and extractable Mo. The relative yield increases for applied Mo and plant Mo concentration could both be predicted reasonably well, though, from the active iron ratio (amorphous Fe/free Fe) and soil pH levels.
Thatch and Tiller Size as Influenced by Residue Management in Kentucky Bluegrass Seed Production1
Authors: Canode C. L. , Law A. G. 
Published: July 2010

AbstractKentucky bluegrass (Poa patensis L.) seed production is significantly greater when in situ post‐harvest residue burning is compared with mechanical removal of straw and stubble. The objectives of this research were to determine the amount of thatch accumulated for various methods of post‐harvest residue removed and to determine the influence of thatch on tiller size and panicle production.Core samples from four cultivars of Kentucky bluegrass where residue had been open‐burned, machineburned, or removed were used for measurement of thatch and tiller size. Tillers were separated into three sizes according to base diameter, induced under field conditions, and grown in a glasshouse to force panicle production.Mechanical removal of straw and stubble left 6.5 metric tons/ha of thatch after one seed crop and 10.1 and 15.2 metric tons/ha of thatch after three and four seed crops. Open burning and machine burning at high ternperatures reduced thatch accumulation about 50%. The total number of primary tillers and the number of large tillers was significantly greater following these treatments. Large tillers (2.0 mm) produced a high percentage of panicles, medium tillers (1.5 mm) produced few panicles, and small tillers (1.0 mm) produced essentially no panicles.It was concluded that thatch reduction and the resulting production of a greater number of large tillers in the autumn was the primary response to post‐harvest residue burning that increased seed yield.
Interaction of Sodium Chloride and Temperature on Germination of Two Alfalfa Cultivars1
Authors: Stone J. E. , Marx D. B. , Dobrenz A. K. 
Published: July 2010

AbstractIdentification of laboratory conditions for isolating alfalfa (Medicago sativa L.) plants which tolerate high temperature and high saline soil during germination and stand establishment would be useful for alfalfa improvement in and and semi‐arid environments. An experiment was designed to determine the germination percentages of ‘U.C. Salton’ and ‘Ladak 65’ alfalfa cultivars at all combinations between sodium chloride osmotic potentials (OP) of 0 to −15 bars and temperatures of 21, 27, 33, and 39 C. U.C. Salton was developed for the low desert Southwest. Ladak 65 was developed for Montana. U.C. Salton showed slight enhancement of germination when the OP was lowered from 0 to −1 bar at 21,27, and 33 C. Ladak 65 showed this enhancement only at 27 C. At lower OP's, the germination percentages declined sharply for both cultivars. There was an interaction between the effects of temperature and OP on seed germination. Cultivar‐temperature and cultivar‐OP interactions were highly significant. A statistical model was established from these data. Quadratic response surfaces were found which had high degrees of fit to the data for each cultivar. The optimal temperature‐OP combinations for germination from the response surfaces were 25.4 C at −1.1 bar for U.C. Salton and 21.4 C at 0 bars for Ladak 65. Germination trends involving salt and temperature could be useful for establishing selection pressures in alfalfa improvement programs.
Contribution of Mycorrhizae to P Nutrition of Crops Growing on an Oxisol1
Authors: Yost R. S. , Fox R. L. 
Published: July 2010

AbstractMost plant species, including the major crops, form symbiotic mycorrhizal associations between their roots and certain fungi which influence nutrient uptake, especially P, from infertile soils. How well‐supplied the phosphate must be before mycorrhizae cease to enhance P uptake is not known; nor have the effects of mycorrhizae on external P requirements of crops been adequately determined in the field. This study examined the influence of mycorrhizae on the P requirements of crops in a tropical field environment on a Tropeptic Eutrustox. Plant growth and P uptake by non‐mycorrhizal and mycorrhizal plants (methyl bromide‐fumigated and nonfumigated soil) were measured at 10 levels of soil P using seven plant species. Brassica chinensis, which does not form symbiotic mycorrhizal associations, consistently grew better and took up more P from the fumigated than from the non‐fumigated soil. All other species growing in nonfumigated plots formed associations with mycorrhizae. In general, plants growing on fumigated soil did not become infected with mycorrhizae. In P‐deficient situations, plant concentration of P was enhanced by the mycorrhizal associations. The levels of soil P at which fumigation ceased to make a difference in the P percentage in plants of the various species were as follows: Glycine max (L.) Merr. (0.1 µg P/ml), Vigna unguiculata L. (0.2 µg P/ml), Allium cepa L. (0.8 µg P/ml), Leucuenu leucocephala (1.6 µg P/ml), Stylosanthes hamata and Manihot esculenta (1.6 + µg P/ml). We suggest that this listing may be the order in which these species depend on mycorrhizae in P‐deficient soils. As a mean of six species growing on the two lowest soil P levels, P uptake by mycorrhizal plants was 25 times greater than by plants without mycorrhizal associations. Thus, some crops appear to be quite dependent upon a mycorrhizal association for P absorption from a soil of high sorption capacity.
Phosphorus Fertilization and Symbiotic Nitrogen Fixation in Common Bean
Authors: Graham P. H. , Rosas J. C. 
Published: July 2010

AbstractSoils in the major bean (Phaseolus vulgaris L.) producing regions of Latin America are frequently deficient in both P and N. With the fertilizer available to small farmers limited, the appropriate strategy for efficient fertilizer use could depend on the relative P requirements for plant and nodule development and N fixation in this species. In this field study the objective was to examine the growth, P distribution, and parameters of N2 (C2H2) fixation of bean cultivars at different levels of P fertilization.Seeds from 30 bean cultivars (replicates) were inoculated and lime pelleted, then sown into a Typic Dristandept soil low in available P. Phosphorus fertilization from 0 to 315 kg/ha as triple superphosphate was applied, then plant and nodule development, P distribution and N2 (C2H2) fixation measured 42 days after planting.Nodules were a strong sink for P, nodule weight increasing ninefold and P concentration in nodules by almost 50% over the range of P fertilization used. Other plant tissues benefited less. Levels of N2 (C2H2) fixation , specific nodule activity, and non structural carbohydrate in nodules were highly correlated with supply of P.Though P concentration in nodules reached 0.27%, there was no indication that the maximum fertilization rate used was adequate for full nodule development or nitrogen fixation. Further, none of the 30 cultivars tested showed reasonable N2 (C2H2) fixation at low rates of P fertilization. It may be concluded that identification of bean cultivars able to grow at low P, but still efficient in Na fixation, will be difficult.
Determination of Physiological Maturity in Oat1
Authors: Lee H. J. , McKee G. W. , Knievel D. P. 
Published: July 2010

AbstractIn studying various ecological and physiological factors affecting the yield of the several small grains, it is important to be able to define the length of the grain fill period, that is the period from anthesis to physiological maturity. Unfortunately, the various small grain crops do not develop a readily recognizable indicator, such as the ‘black layer’ in corn, Zea mays L., and tested methods to evaluate physiological maturity in small grains seem to be lacking. Our objective was to evaluate several techniques for determining when physiological maturity occurs in spring oat, Avena sativa L. In this study, five methods of determining physiological maturity were evaluated. Field grown plants of ‘Astro,’ ‘Noble,’ and ‘Otee’ spring oat were tagged when the spikelets at the second node from the base of the panicle were at anthesis. Plants were grown on a Murrill fine silty loam (a mixed, mesic Typic Hapludults.). Beginning 15 days after anthesis for each cultivar, spikelets at the tagged node were sampled daily, and an evaluation made of color changes in certain panicle parts, the uptake of a red, water‐soluble dye, and the uptake of14C‐sucrose. The groats were then weighed, freeze‐dried, and reweighed to secure dry weight and fresh moisture content. Lack of dry weight changes significant at p ⩽ 0.05 was used as the standard method to define physiological maturity and the other techniques compared to this. When half of the glume tips no longer took up the red dye and approximately 75% of the glume surface was yellow it provided a useful, nondestructive estimation of physiological maturity as defined by the dry weight method. Small amounts of 14C‐sucrose were taken up for a few additional days, but dry weight changes were not significant at p ⩽ 0.05. Groat and grain moisture content did not satisfactorily indicate physiological maturity. Observations of color changes in the glumes and cessation of dye uptake, either alone or in combination, provide a method of comparing the length of the oat fill period under various cultural and environmental conditions and for various genotypes.
Maize Yields and Soil Nutrient Levels With and Without Pesticides and Standard Commercial Fertilizers1
Authors: Lockeretz William , Shearer Georgia , Sweeney Susan , Kuepper George , Wanner Diane , Kohl Daniel H. 
Published: July 2010

AbstractBecause of increases in the price of chemical inputs to agriculture, uncertain supplies, and environmental concerns, a reduction in pesticide and fertilizer use may become increasingly desirable, if it could be achieved without a major reduction in output. For this reason, it is of interest to compare yields obtained under present conventional practice with those obtained at the lower limit of chemical intensiveness. This paper reports maize (Zea mays L.) yields on two groups each of 26 commercial mixed grain and livestock farms covering a wide range of soil types in the western Corn Belt. One group was managed with conventional fertilization and pest control practices, while no herbicides, insecticides, or standard commercial fertilizers were used on the other. The mean yield from the convenional fields was 8.5% higher than from the matched fields on which conventional fertilizers or pesticides were not used. The difference was not statistically significant (P<90%). Conventional maize yields tended to be higher than maize yields on fields which received no pesticides or fertilizers under favorable growing conditions and lower when conditions were adverse. Grain from the fields receiving pesticides and fertilizers had a significantly higher crude protein content. These fields also had a significantly higher incidence of Diplodia stalk rot and lodging. Soils from fields receiving no pesticides and fertilizers had a significantly higher (P>95%) organic C content, as well as higher total N (P>90%), but lower P1 phosphorus (P>90%). Differences in P2 phosphorus, exchangeable K, C:N ratio, CEC, and pH were not significant (P<90%)