bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Root Activity in Vegetative and Reproductive Soybean Plants1
Authors: Jones C. Allan , Reeves Alvin , Scott John D. , Brown D. A. 
Published: July 2010

AbstractAttempts to delineate the factor(s) which limit soybean (Glycine max (L.) Merrill) yields suggest that one of the reasons may be the decline in new root growth, longevity, and/or metabolic activity of the root system as the plant changes from the vegetative to the reproductive stage of growth. The objective of this research was to investigate the absorption and desorption characteristics of intact soybean roots of plants in the vegetative and reproductive stages of growth. Compartmental analysis was used to determine whether the movement of 45Ca and 32P within the roots of intact soybean plants is different in the vegetative and reproductive stages. Soybeans were grown under greenhouse conditions in nutrient solution. Half the plants were induced to flower at 7 weeks of age, by reducing the day length from 16 to 12 hours. At 12, 14, 15, and 16 weeks of age both vegetative and reproductive plants were transferred to a controlled environment chamber, and 45Ca and 32P were used to characterize nutrient translocation to the tops and nutrient efflux from the root tissue to the nutrient solution. At 16 weeks of age the cation exchange capacity, mitotic activity, and oxygen consumption of the roots of the greenhouse‐grown plants were determined. The initial rate of 45Ca and 32P efflux from the cytoplasmic compartment and the initial 45Ca and 32P content of the cytoplasmic compartment of the roots of reproductive plants were twice those of vegetative plants. Oxygen consumption and mitotic activity were greater in the roots of vegetative plants. Cation exchange capacity was greater in the roots of reproductive than in vegetative plants. There was little evidence that the accumulation of 32P and 45Ca in the tops, the rate constants of 32P and 45Ca from the cytoplasmic or vacuolar compartments, or the initial rate of efflux of 32P or 45Ca from the vacuolar compartments differed significantly in vegetative and reproductive plants. The implications of the results are discussed with regard to nutrition of reproductive soybeans.
Relationship Between Soil Test and Small Grain Response to P Fertilization in Field Experiments1
Authors: Fixen P. E. , Carson P. L. 
Published: July 2010

AbstractYield data from 74 small grain field experiments over a l3‐year period were used to evaluate the relationship between various soil tests and P response. Past field studies have resulted in low correlations between P soil test value and yield response, indicating that either alternative soil tests should be evaluated or additional soil and climatic factors should be considered. The soil tests examined in this study were the Bray 1 (soil to solution ratio of 1:7, 1:10, 1:20, and 1:50), Olsen P, and P sorption index of Bache and Williams. The crop species included were Triticum aestivum L., Hordeum vulgare L., and Avena sativa L. At each location soil samples were taken and stored and yield response to P fertilizer, applied with the seed, was recorded. The highest correlation between soil test value and yield response to P fertilization was found with the Bray 1, 1:50 (r2 = 0.41). An additional 23% of the yield response variation could be explained by including six additional variables in a multiple regression analysis employing dummy variables. Borolls were generally less predictable in their response to P than were Ustolls. Ustolls responded less to P fertilization than Borols while soils of the vertic subgroup responded more to P fertilizer according to the Bray 1, 1:50 soil test. The r value between P sorption index and yield response on alkaline soils was −0.70 (the highest of the soil tests examined) but was near zero for acid soils. Differences were also noted in degree of response between parent materials and crop species. Organic matter content appeared to influence response on some soils.
An Electronic Sensor for Vapor‐Pressure Deficit of the Air1
Authors: Johnson W. C. , Davis R. G. 
Published: July 2010

AbstractThe parameter of vapor‐pressure deficit (VPD) is used in several methods of calculating potential evapotranspiration. This note describes an electronic sensor for measuring VPD whose principle of operation is based on wet and dry‐bulb psychrometry and utilizes thermistors and silicon diodes as wet and dry‐bulb probes. These probes produce two voltages which, when multipled together by an inexpensive, commercially available, analog multiplier, result in an output voltage proportional to VPD that can be recorded continuously on a strip chart recorder. The VPD sensor has shown good reliability in actual field tests with accuracy that would not be a limiting factor in calculating potential evapotranspiration. Detailed information on construction and operation of the sensor is available from the authors and will be mailed on request.
Factors Associated with Zn Chlorosis in Dryland Beans1
Authors: Khan Adam , Soltanpour P. N. 
Published: July 2010

AbstractDryland pinto beans (Phaseolus vulgaris L. ‘San Juan’) are grown in more than 40,000 ha in the San Juan Basin of Colorado. Chlorosis and root rot are two major problems encountered by the bean growers. This research was initiated to investigate the cause of chlorosis of beans. Paired plots, one chlorotic and the other relatively green, were selected on 18 farms in 1975 and 1976. The soils of the experimental sites belong to Ackmen, Witt, and Pulpit series of Fine‐silty, mixed, mesic family. The Ackmen series belong to the Cumulic Haplustolls. The Witt and Pulpit series belong to the Ustollic Haplargids. Yield, root rot, soil factors, and plant composition were compared for the chlorotic and the green plots. In 1976 the chlorotic plots were divided into two subplots, one receiving zinc spray to confirm the results of regression analysis that suggested zinc deficiency was the cause of chlorosis. The chlorotic plots had significantly higher mean levels of soil moisture and pH, and lower organic matter than the green plots. The chlorotic leaves had higher mean levels of P and P/Zn, and lower Zn than the green leaves. The chlorotic plants had a higher incidence of root rot than the green plants. The mean soil P and soil Zn availability indexes were not different in the chlorotic and the green plots. Soil Zn levels in all plots except one were lower than 0.5 ppm. It was observed that the chlorotic areas were situated lower on the slope than the green areas, with a marked demarcation between them. The regression analysis suggested that 72% of the variability in yield was due to leaf P/Zn ratio, root rot and their positive interaction. Other measured variables did not significantly contribute to R2. Spraying the chlorotic plants with a solution containing 1% zinc sulfate removed chlorosis and increased the yield by 18 to 92%. In general, the yield of the chlorotic plants sprayed with zinc solution did not increase to the level of the green plants. This difference was attributed to the higher root rot index of the chlorotic plants. The data suggested that higher soil moisture in low lying areas increased the P availability and thus caused a P‐induced Zn deficiency in the bean plants growing in these soils of marginal Zn availability.
Influence of Date of Harvest on Yield and Agronomic Characteristics of Meadowfoam1
Authors: Johnson J. W. , Devine M. B. , White G. A. 
Published: July 2010

AbstractLimnanthes alba Benth. is a winter annual and a potential new oil crop. Effective harvesting techniques are necessary to improve the seed retention of Limnanthes before its acceptance as an agronomic crop. The influence of time of harvest on seed yield, seed weight, and oil content was determined. The use of paraquat, 1,1′‐dimethyl‐4,4′‐bi‐pyridinium ion, as a harvest aid to hasten maturity and reduce shattering was evaluated. Seed yield, seed weight, and oil content were measured in the field on two plant introductions grown on a Matapeake silt loam (fine‐loamy, mixed mesic Typic Hapludults). A 20 to 37% decrease in yield was observed when the harvest was delayed 2 weeks. Harvesting 1 week before maturity resulted in the highest yield (1,461 kg/ha). The highest oil content (26%) and seed weight were obtained by harvesting at maturity. Paraquat was unacceptable as a harvest aid because of its adverse effects on yield and oil content.
Corn Residue Management and Weed Control in Close‐Drilled Soybeans1
Authors: Moomaw R. S. , Burnside O. C. 
Published: July 2010

AbstractIncreased use of reduced tillage systems has contributed to larger amounts of plant residue being left on the soil surface. The purpose of this study was to determine the effects of several methods of corn (Zea mays L.) residue management on the effectiveness of herbicide applied to a succeeding soybean [Glycine max (L.) Merr.] crop. Corn residue management methods used were (a) stalks not shredded but soil disked; (b) stalks shredded and soil disked; (c) stalks shredded and soil disked and plowed. Methods of managing the prior year's corn residue did not affect performance of soybean herbicides at two locations in eastern Nebraska over a 3‐year period. Weed control and soybean yield of closedrilled soybeans did not differ significantly between herbicide rates suggested on the labels and one‐half those rates, but there was less weed control when one‐half the labelled rates of the herbicide was used.
Establishing Wheat After Soybeans in Double‐Cropping1
Authors: Sanford J. O. 
Published: July 2010

AbstractA method whereby wheat (Triticum aestivum L.) can be sown earlier would be a distinct advantage in a wheatsoybean (Glycine max (L.) Merr.) double‐cropping system. ‘Abe’ wheat overseeded in standing soybeans about 1 October was compared with conventionally seeded wheat after soybean harvest (1 to 10 November). Wheat overseeded consistently outyielded the conventionally seeded wheat. The optimum seeding rate for overseeding wheat was 101 kg/ha. Overseeded wheat failed during 1 of 4 years, because the soybean canopy was only 50% closed because of late planting (15 July).The growth regulator, 2, 3, 5‐triiodobenzoic acid (TIBA) was applied to ‘Bragg’ soybeans at different growth stages to create canopies with varying degrees of closure. Plots with these different canopies were overseeded with ‘Abe’ wheat at a rate of 134 kg/ha about 1 October (when the topmost soybean leaves began to turn yellow). Emergence and yield of wheat were significantly greater when no TIBA was applied (completely closed canopy) than when TIBA was applied and the canopy was not completely closed.Overseeding wheat in standing soybeans in double‐cropping was found to be an acceptable method of establishing the wheat crop However, emergence and yields of wheat can be expected to be reduced when the soybean canopy is less than completely closed.
Differential Cultivar Tolerance in Soybean to Phytotoxic Levels of Soil Zn. II. Range of Zn Additions and the Uptake and Translocation of Zn, Mn, Fe, and P1
Authors: White M. C. , Chaney R. L. , Decker A. M. 
Published: July 2010

AbstractThis investigation was part of a general characterization of Zn tolerance among cultivars of an agriculturally important plant species. Greenhouse studies were conducted to further evaluate the effect of soil Zn additions on soybean (Glycine max L. Merr.) cultivar differences in Zn tolerance, as well as plant Zn, Mn, Fe, and P contents. Four cultivars selected from a previous Zn tolerance screening trial (‘Wye’ and ‘Hudson Manchu’, tolerant; ‘York’, sensitive; ‘Columbus’, normal) were grown for 4 weeks on a fertilized Sassafras sandy loam (Fragiudult) amended with a wide range of Zn additions at pH 5.5 (nine additions between 1 and 131 ppm Zn) and 6.5 (10 additions between 1 and 524 ppm Zn).Leaf dry weight reductions were curvilinear across the Zn additions at each pH, with yield increases occurring at the lower Zn treatments. For all cultivars, root dry weight was unaffected by the Zn additions at the lower pH and significantly reduced at the higher pH by Zn additions greater than 262 ppm. Significant cultivar differences in leaf dry weight yields were observed at the higher Zn treatments.Leaf and root Zn contents increased linearly with increasing soil Zn at each soil pH (root r2 > 0.92, leaf r2 > 0.93 for all cultivars). The soil pH strongly influenced plant Zn contents; at an equivalent Zn addition, tissue values at pH 6.5 were approximately one‐third as great as at pH 5.5. Differential absorption and translocation of Zn was shown by the cultivars; at both pH levels, Hudson Manchu absorbed more Zn but translocated less than the other cultivars.Generally, leaf yield reductions of 20% corresponded to leaf Zn contents greater than 620 ppm at both pH levels; however Hudson Manchu had only 370 ppm Zn in its leaves at 20% yield reduction at pH 6.5. Cultivar differences in both soil and leaf Zn contents at a 20% reduction for leaf dry weight illustrate the inherent weakness of foliar analysis as a monitoring tool for available metals at toxic levels.Root Mn was increased linearly by soil Zn additions at both pH levels, while leaf Mn increases were curvilinear at pH 5.5 and linear at pH 6.5. Leaf Mn concentrations at both pH levels reached reported toxic levels (> 500 ppm) illustrating the complex nature of Zn phytotoxicity. DTPA‐extractable Mn was unaffected by soil Zn additions at both pH levels.Foliar (combined trifoliolate leaves) Fe, at pH 5.5 and 6.5, and P at pH 6.5, decreased with increasing soil Zn, but did not approach reported deficiency levels. Similar amounts of Fe and P were found in Zn‐tolerant and Znsensitive cultivars.These results illustrate the complex nature of Zn phytotoxicity and the importance of cultivar selection for cropping soils amended with metal‐containing wastes.
Destruction of Sod‐seeded Legume Seedlings by the Snail (Polygyra cereolus1
Authors: Kalmbacher R. S. , Minnick D. R. , Martin F. G. 
Published: July 2010

AbstractFlorida's perennial forage grasses, dormant during winter and early spring, provide little new forage unless overseeded with a cool‐season crop such as clover (Trifolium spp.) or alfalfa (Medicago sativa L.). Sod‐seeding legumes in bahiagrass (Paspalum notatum Flügge) has resulted in poor establishment unless areas were desiccated with 0.28 kg/ha of paraquat and hurned 48 hours later. Poor stands were believed to be due to seedling loss by the snail (Polygyra cereolus Muhlfeld). These experiments were designed to test this hypothesis and determine if burning killed snails.Five experiments were conducted. 1) Populations were estimated by counting snails in 0.3m2 areas and by tallying snails in traps. 2) To determine legume mortality rate, 0, 1, 3, 5, and 7 snails were placed in enclosures with 20 white clover (T. repens L.) seedlings. 3) In a similar experiment two or four snails were exposed to 40 white clover seedlings drilled in rows. 4) Alfalfa, red (T. pratense L.) and white clover were exposed to snails to determine differences in legume susceptibility. 5) Finally, the temperature was recorded 2.5 cm above, 2.5 cm below, and at soil surface during the burning of bahiagrass. Snails were placed on the soil before the burn and their mortality was determined.During a 44‐day trapping period in newly seeded legume plots there was an average total of 13.6 snails found vs. 14.0 snails in unseeded bahiagrass. The number of snails per 0.3m2 was 0.9 vs. 0.84 snails in the respective areas.Greenhouse studies indicated that P. cereolus was responsible for legume mortality. White clover was more susceptible to loss than red clover or alfalfa. More than one snail per 20 seedlings constituted a threat to legume establishment particularly when added to losses from other causes.Burning bahiagrass after desiccation with paraquat resulted in 98% mortality of P. cereolus. Temperatures at the soil surface rose from 27 to 83 C in 75 sec then dropped to 37 C after 5 min.
Effect of Surface Winds on the Spectral Signatures of Crops1
Authors: Rao V. R. , Brach E. J. , Mack A. R. 
Published: July 2010

AbstractSpectral interpretation of quantitative measurement of the reflected radiation from plants by remote sensing requires consideration of the environmental conditions and structural aspects of the plant under which the measurements were made. Depending on wind speed and direction, it was found that for certain plants, such as cereal crops, radiance fluctuated 10 to 20% more in the 450 to 650 nm than in the 650 to 750 nm range. Wind speeds up to 32 km/hr caused increasingly greater fluctuation for cereal crops than for clipped sod and bare soil. A calibrated grey reference scale showed little effect of wind within the range of speeds observed in this study.
Role of Root Temperature on Shoot Growth of Two Kentucky Bluegrass Cultivars1
Authors: Aldous D. E. , Kaufmann J. E. 
Published: July 2010

AbstractShoot growth inhibition and changes in carbohydrate levels occur in cool‐season grasses under midsummer conditions. Cultural practices, such at thatch removal or topdressing, could alter high temperature extremes of the crown and root. Thus, the objective of this study was to determine the role of root temperature on shoot growth rate and water soluble carbohydrate (WSC) levels in plant parts of ‘Merion’ and ‘Nugget’ Kentucky bluegrass (Poa pratensis L.).The turfgrasses were established from seed on coarse sand in the greenhouse. After 12 weeks the pots were transferred to an environmental growth chamber where air temperatures were increased from 22 to 38 C in 4 C increments every 2 weeks. The effects of root zone temperatures controlled at 22 C (CRT) were compared to noncontrolled temperatures (NRT) in which the root zone was allowed to equilibrate with the air temperature. Shoot growth above 4.0 cm. was clipped at the end of each temperature increment from 22 to 34 C. After the 38 C exposure plants were separated into verdure (live leaf tissue), “thatch” (dead leaf tissue), crowns, and roots.Shoot growth of Merion Kentucky bluegrass grown at NRT, was greatest at 26 C and was significantly reduced at 30 and again at 34 C. Shoot carbohydrate levels were lowest at 26 and 30 and highest at 34 C. At 38 C, verdure and crown carbohydrate levels were significantly higher than those of the roots.The growth rate of Nugget (NRT) at 26 C was not as rapid as for Merion. Shoot WSC levels were high at 26, 30, and 34 C compared to Merion Kentucky bluegrass. At 38 C, root WSC levels were significantly higher in roots than verdure or crown. The greater high temperature tolerance of Nugget was documented through a higher verdure‐thatch ratio.Survival of both cultivars was enhanced by controlling the root temperature at 22 C (CRT). Shoot WSC levels at all temperatures were significantly lower at CRT compared to NRT in Nugget. This was true in Merion only at 34 C. Root WSC levels in Merion at CRT were at the high level found for Nugget at both NRT and CRT. Shoot growth cessation at supraoptimal temperatures may result from a high temperature‐labile process in the root. Loss of root carbohydrates appears to increase the temperature lability of the process.
Dry Matter and Morphological Responses to Temperatures of Alfalfa Strains with Differing Ploidy Levels1
Authors: Arbi Nitza , Smith Dale , Bingham E. T. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) is grown in a diversity of temperature areas, but there is little information on the response to temperature of strains of different ploidy levels. The objective was to study the response of alfalfa strains of 2x, 4x, and 6x levels of ploidy when grown at three different temperature levels. Plants were grown from seed in pots of soil in three growth chamber regimes; hot (H) 33 C day/24 C night, warm (W) 27/18 C, and cool (C) 21/12 C. All chambers had 18‐hour daylengths. Plants were harvested with two schedules; (i) by date (43 days after seeding) and (ii) by maturity (at first flower). First flower stage generally was delayed as temperatures decreased. The 2x was the first strain to flower in the H and W regimes and 4x in the C regime, while the 6x strain was last to flower in all regimes. At the 43‐day harvest, shoot height and weight of plant parts for each strain generally were highest in the W regime, followed in order by the H and C regimes. Weights of plant parts at first flower for each strain generally were highest in the C regime, followed in descending order by the W and H regimes, except that 6x yielded least in W. Highest herbage growth rate at first flower was in the C regime for the 2x and in the W or C regime for the 4x, while the rate was similar at all temperatures for the 6x. Total plant growth rates (herbage plus roots) of all three strains at first flower were highest in the C regime followed in descending order by the W and H regimes, except 6x was similar at H and W. Leaf area, leaf weight, and specific leaf weight (SLW) generally increased as temperature decreased. However, leaf area of 2x cut by date and SLW of fix cut at first flower were lowest in W rather than H regime. Thus, the strains reacted differently to temperature. The 2x appeared to grow best in the C regime and the 4x in either the W or C regime. The 6x showed a broad adaptation to temperatures, growing about the same at all temperatures. Development of alfalfas with different ploidy levels than the cultivated tetraploids may be a means of obtaining cultivars with broader temperature adaptation or with better adaptation to low or high growing temperatures.
Rapid Evaluation of Foliar Fertilizer‐induced Damage: N, P, K, S on Corn1
Authors: Neumann Peter M. 
Published: July 2010

AbstractFoliar spraying of crops with fertilizer solutions often causes leaf bum, which reduces the photosynthetic area of the leaves and can reduce yields. Damage can be avoided sometimes by careful control of factors such as spray droplet size, wetting agents, ambient temperature, pH, and concentration of solutes. However, information concerning the mechanism inducing burn damage or the comparative merits of different fertilizer sources of the same mineral is limited. The objects of this work were: 1 to use a rapid laboratory assay to compare the damaging effects of various fertilizer sources of N, P, K, and S on leaf cell membranes, 2 to identify the mechanism of membrane damage by fertilizer solutions, and 3) to make a preliminary evaluation of any correlation between solute‐induced membrane damage and leaf bum in the field. The laboratory assay consisted of a 4‐min vacuum infiltration of 0.3‐cm leaf segments with test solution followed by assay of UV‐absorbing materials leaked subsequently into a distilled water rinse. Threshold concentrations of fertilizers causing membrane damage symptoms were determined for nine fertilizer sources.Damaging concentrations of N ranged from 3.5 to 31 g/liter depending on the fertilizer assayed. Damaging concentrations of various P, K, and S sources ranged from 3.8 to 11 g/liter for P, 12.2 to 22 g/liter for K, and 6.4 to 8.2 g/liter for S. No evidence was found for the existence of a causal relationship between either pH, molarity, conductivity, or osmotic potentials of test solutions and the onset of membrane damage. Preliminary field trials showed that the assay could predict damage trends for urea and urea phosphate sprays.