bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Irrigation and Rhizobium japonicum Strains on Yields of Soybeans Grown in a Lakeland Sand1
Authors: Mahler R. L. , Wollum A. G.
Published: July 2010

Under existing management technology, Lakeland sands (Typic Quartzipsamments) produce low yields of soybeans [Glycine max (L.)Merr.] in North Carolina. These soils have an available water holding capacity of only 4.0% on a weight basis and as a result require about 2.5 cm of water every 5 to 6 days during the growing season to produce acceptable crop yields. In addition, Lakeland sands usually have extremely low or a totally nonexistent indigenous population of Rhizobium japonicum. Information on irrigation and nodulation effects is needed to make these soils more productive.

The objectives of this study were to investigate the influence of irrigation and inoculation with different R. japonicum strains on yields of soybeans grown in a Lakeland sand. The study was conducted at the Sandhills Research Station at Jackson Springs, North Carolina. Additional nonirrigated plots inoculated with strains 31, 110, and 122 were initiated on finer textured North Carolina soils for comparative purposes to the Lakeland sand.

Soil moisture treatments included plots not irrigated and plots irrigated each week with 2.5 cm of water. The five inoculation treatments consisted of a set of noninoculated plots and plots inoculated with strains of R. japonicum representing serogroups 31, 76, 110, and 122 at the rate of 50 ✕ 104 cells per cm of soybean row. Numbers of soil rhizobia were monitored throughout the study using a plant infection and MPN technique.

Irrigated soybean seed yields were significantly greater when inoculated with rhizobia of either serogroup 110 or 122 than yields from noninoculated but irrigated plots. Inoculation without irrigation did not increase soybean yields. It was also observed that inoculated, irrigated soybeans had greater nodule mass and numbers of nodules than the nonirrigated and/or noninoculated plots. All four serogroups used in the study adequately nodulated soybean roots under irrigation and produced fewer nodules on soybean roots in the nonirrigated plots. On the basis of seed yield, strain ranking from best to worst was: 122>110>31>76. The noninoculated controls yielded higher than serogroup 76 but less than those soybeans in plots inoculated with serogroup isolate 31.
Predicting In‐Season N Requirements of Sugarbeets Based on Soil and Petiole Nitrate1
Authors: Gilbert W. A. , Ludwick A. E. , Westfall D. G.
Published: July 2010

Crop quality is a continuing concern of the sugarbeet (Beta vulgaris L.) industry. A carefully managed N fertilizer program can significantly contribute to improved quality. The objectives of this study were to evaluate sidedressing N for correction of mid or late season N deficiencies and to evaluate an approach suggested by Giles et al. to predict the occurrence of midseason N deficiency. This method uses the preplant residual soil NO3− level, preplant N fertilizer rate, and one midseason petiole NO3‐N Concentration in a decay equation to predict the date the petiole NO3‐N level will drop to 1,000 ppm.

Field experiments were conducted at two locations in 1975 and two different locations in 1976 in eastern Colorado. The soil at these sites (Argiustolls or Paleustolls) had an alkaline pH (7.7 to 7.9) and contained a wide range of soil NO3‐N (57 to 232 kg/ha) at planting. Rates of preplant N ranged from 0 to 168 kg/ha and a sidedress N rate of 84 kg/ha was applied at different dates between late May and mid‐August. Plant petioles were sampled at approximately 3‐week intervals during the season.

Nitrogen deficiency was effectively corrected by sidedressing N through June. Delaying application until after mid‐July resulted in yield loss and frequently depressed sucrose concentration. Purity was not affected by sidedressing N at any location. Maximum sugarbeet quality was associated with petiole NO3‐N concentrations of <2,000 ppm on 1 September. The petiole decay equation of Giles et al. to predict NO3‐N concentrations on this date was reasonably successful. The coefficient of determination for calculated vs. actual NO3‐ decline in half‐life days (t½) was r2 = 0.63. The average t½ error was 6 to 7 days. This approach shows promise for evaluating in‐season N nutrition sufficiently early to correct incipient deficiencies before serious or possibly any yield loss occurs.
Agronomic Evaluation of Cytozyme as a Growth Regulator1
Authors: Ryan J. , Saghir A. R. , Shafyuddin M. , Barsumian A.
Published: July 2010

In recent years, fertilizer costs have spiralled due largely to higher energy costs involved in fertilizer manufacture. This development has underlined attempts to provide alternatives to or supplement fertilizers with cheaper sources, especially in developing countries. Cytozyme is one of several commercially available chemicals purported to have such an effect. This study evaluated the potential of this compound as a growth stimulant for sugarbeet (Beta vulgaris L.) in the field corn (Zea mays L.) and tomato (Lycopersicum esculentum Mill.) in the greenhouse. The chemical was applied to the seed prior to planting, and directly on the soil alone and in combination with conventional organic manures, and with a commercial inorganic compound fertilizer. However, under the conditions of these trials, none of the Cytozyme compounds or a similar material Goe‐mar had any significant effect on the parameters studied. These results question the effectiveness of legislation regarding the use of such materials in agriculture.
A Heat Exchanger for Soil Temperature Control of Potted Plants1
Authors: Robacker D. C. , Flottum P. K. , Erickson E. H.
Published: July 2010

A heat exchanger that regulates soil temperature of individually potted plants is described. The device is a water jacket into which a single pot is inserted such that drainage of the potted plant is not restricted. Heat exchange occurs between the soil of the plant and water which circulates through the water jacket. In experiments, heat exchangers connected in series maintained soil temperature within 3 C of a desired value. Advantages and disadvantages of this method of soil temperature regulation are discussed.
Weed Control in Double Cropped Corn, Grain Sorghum, or Soybeans Minimum‐Till Planted Following Canning Peas1
Authors: Ndon B. A. , Harvey R. G. , Scholl J. M.
Published: July 2010

Double cropping involving minimum‐till planting has become popular in many parts of the USA. In Wisconsin, double‐cropping usually includes canning peas (Pisum sativum L.) as the spring crop. Trifluralin (a,a,a‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) is used for weed control in much of this pea acreage. Since effects of trifluralin residues alone or in combination with subsequent herbicide treatments on summer crops and weeds were unknown, experiments were conducted at the Univ. of Wisconsin Arlington Farm in 1977 and 1978 on a Plano silt loam (Typic Argiudoll, fine, silty, mixed mesic) with 3.5 to 4.0% organic matter. Corn (Zea mays L.), grain sorghum (Sorghum bicolor L. Moench), and soybeans [Glycine max (L.) Merr.] were minimum‐till planted following canning peas grown with or without preplant‐incorporated trifluralin. Effects of two herbicide combinations and an untreated control were compared in each of the summer crops.

Trifluralin controlled both broadleaf and grass weeds in canning peas but did not increase shelled pea yield. Average weed growth in corn, grain sorghum, and soybeans following peas treated with trifluralin was reduced 52, 52, and 62%, and average grain yields of corn and soybeans were increased 10 and 28%, respectively, compared with the same crops following untreated. peas. Trifluralin residues reduced grain sorghum stands (44%) and yields (17%).

Alachlor [2‐chloro‐2′, 6′‐diethyl‐N‐(methoxymethyl) acetanilide] + atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] + paraquat (1,1‐dimethyl‐4,4′‐bipyridinium ion) was more effective in reducing weed growth in minimum‐till corn than alachlor + cyanazine [2‐chloro‐4‐(1‐cyano‐1‐methylethylamino)‐6‐ethylamino‐s‐triazine] + paraquat. There was no significant difference between the two combinations in terms of corn grain yield, however. Alachlor + cyanazine + paraquat following trifluralin in peas resulted in better weed control in minimum‐till corn than a similar treatment applied to corn planted following peas grown without trifluralin. Atrazine + paraquat and 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] + paraquat also provided excellent weed control in grain sorghum, and alachlor + linuron [3‐(3‐4‐dichlorophenyl)‐1‐methoy‐1‐methylurea] + paraquat, and linuron + paraquat provided excellent weed control and increased grain yields in soybeans when both crops were minimum‐till planted after peas treated with trifluralin. Overall, soybeans appeared to be the most successful of the three crops when minimum‐till double‐cropped following peas under southern Wisconsin conditions.
Sulfur Fertilization Effects on the Constancy of the Protein N:S Ratio in Low and High Sulfur Accumulating Crops1
Authors: Gaines T. P. , Phatak S. C.
Published: July 2010

An accurate quantitative separation of protein from non‐protein in plant tissue is necessary for answering the question whether the protein N:S ratio, (N/S)p, is constant or is affected by plant part, age, or nutrient supply. Previous studies in our laboratory have shown that plant tissue extracted with hot 0.5% acetic acid to remove non‐protein N (NPN) prior to Kjeldahl analysis give results very close to those for true protein N (PN). The objective of this study was to determine the effect increased S rates during growth had on the constancy of the (N/S)p ratios of low and high S‐accumulating crops.

Corn (Zea mays L.), soybean (Glycine max L. Merr.), and cowpea (Vigna Unguiculata L. Walp.) were selected as low S‐accumulating plants and tomato (Lycopersicon esculentum L. Mill.), cotton (Gossypium hirsutum L.), and okra (Abelmoschus esculentum L. Moench.) as high S‐accumulating crops. Plants were grown hydroponically with S levels of 0, 16, and 32 ppm and constant N levels (126 ppm N) and harvested when the 0 ppm S‐treated plants showed moderate S deficiency. Samples were analyzed for protein S (PS), non‐protein S (NPS), total S (TS), PN, NPN, and total N (TN).

Increased S levels increased the dry weights of corn, soybean, cowpea, and tomato tops and soybean roots. Protein S had a greater demand for limited S than NPS. Non‐protein S began to accumulate only after PS demands were satisfied. Low S‐accumulating crops had higher and more constant (N/S)p ratios than high S‐accumulating crops. High S‐accumulating crops showed a slight but consistent decrease in (N/S)p ratios due to proportionately higher PS levels when S supply was increased. When S supply was sufficient, the (N/S)p ratios were 15 to 16 for corn, 20 for soybeans, 15 for cowpeas, 12 for tomatoes, and 8 to 9 for cotton and okra. The accuracy of the (N/S)p ratio is contingent on the method of fractionating protein from the non‐protein fraction.
Seasonal Variation of Rhizobium meliloti in Alfalfa Hay and Cultivated Fields in North Carolina1
Authors: Mahler R. L. , Wollum A. G.
Published: July 2010

Little is known about native populations of rhizobia in soils of the southeastern United States. This study was undertaken to observe the influence of season on fluctuations of native soil Rhizobium meliloti populations in cultivated and alfalfa (Medicago sativa L.) hay field environments throughout North Carolina.

Soil samples were collected from the Ap horizons of fields in three physiographic regions of North Carolina every 30 days for a 14‐month period. Rhizobium meliloti were enumerated using a most‐probable‐number (MPN) technique and alfalfa as the host for plant infectivity tests. Serial dilution and pour plate techniques were used to determine bacteria.

The cultivated fields did not have a recent history of alfalfa. Conversely, alfalfa hay fields had been in alfalfa continuously for at least 2 years. Larger soil populations of R. meliloti existed in alfalfa hay fields than in cultivated fields. Seasonal variation was evident in North Carolina alfalfa hay fields with populations averaging 1.3 ✕ 105/g soil in April and 1.2 ✕ 104/g in October. Seasonal distribution differences were not noted in cultivated fields. Rhizobium meliloti constituted from 0.01 to 1.67% of the total aerobic bacterial population in alfalfa fields and < 0.001 to 0.01% of the population in cultivated fields.
Portland Cement for Liming a Strongly Acid Soil1
Authors: Ernst F. F. , Stivers R. K.
Published: July 2010

Studies have shown that Portland cement will neutralize soil acidity and increase crop yields on slightly acid soils. However, the cement has not been compared with lime for this purpose on strongly acid soils. A pot experiment was conducted in a controlled‐climate chamber to determine crop response to two levels (0.5 and 1.0% by weight) of commercial portland cement and lime (reagent grade calcium carbonate added to soil). Ockley clay loam (fine‐loamy, mixed, mesic Typic Hapludalf) subsoil with a pH of 4.8 was used. Corn (Zea mays L.) was grown 29 days followed by soybeans (Glycine max L. Merr.) grown for 31 days. Soil pH was raised about the same with equal rates of either lime or portland cement. Dry weight of corn plant top growth was greatest with the 0.5% cement treatment. Total uptake of N, P, K, Ca, Mg, Zn, Cu, Fe, and B by corn grown on this 0.5% cement treatment was also high. For soybeans, all cement and lime treatments produced more plant dry weight than the check treatment (no cement or lime added). Concentration and uptake of Mn in both corn and soybeans were greatest in the check treatment. Only the soybeans had Mn toxicity symptoms.
Nutrient Uptake and Supply to Tomato Plants in a Water Culture System1
Authors: Ben‐Asher J. , Gordon J. M. , Liner A. , Zarmi Y.
Published: July 2010

In horticulture a wide variety of soilless culture is in use. Among them is water culture. In order to provide a quantitative approach for fertilization policy, the kinetics of K+, NO3−, and O2 uptake by tomato (Solanum lycopersicum ‘Naama’) plants in a water culture has been investigated. A solution for a one‐dimensional time‐dependent model is given. Experiments were conducted in 3‐m long channels of a homogeneous nutrient solution. Predicted results agreed with the measured data. For cases in which the Michaelis‐Menten inhibition factor is much smaller than the initial ion concentration, the time dependence of the depletion curve can be approximated by a linear form, which when expressed in terms of dimensionless variables is the same for all ions. The model suggests an algorithm for a number of decisions that should be taken through the process of fertilization. Finally, when extended to the use of saline water under evaporative conditions, the model determines explicitly the worst quality irrigation water that can be used.
Radio Detector and Peg Technique for Locating Sampling Sites in the Field1
Authors: Read D. W. L. , Cameron D.R.
Published: July 2010

It is usually difficult to relocate specific sites in fields. Many methods have been used, including metal detectors, permanent stakes and measuring from bench mark sites. A new system has been developed which has advantages over all these methods. It consists of a peg (transponder) that can be buried below cultivation depth and an easily operated detector that can detect the peg from approximately 2 m distance and home in on the exact position. The accuracy is within 5 cm when the peg is buried at a 1‐m depth. The equipment is of sturdy construction and the pegs remain useable for many years.
A Comparative Evaluation of Three Tests for Determining Plant‐Available Manganese in Soils1
Authors: Sharpe R. R. , Parks W. L.
Published: July 2010

Amounts of manganese extracts from soil by three well‐known methods were compared to each other and to soil levels of Ca, P, Fe, and K and soil pH. Seventy‐one soil samples, representing seven soil series, which are members of either the Ultisol or Alfisol orders, were used in the comparisons of soil extraction procedures. The average amount of soil Mn extracted by each procedure was determined for each soil series. The correlations among extractants were very high and the Mehlich‐1 procedure extracted three to four times more Mn than the DTPA procedure and five to six times more than the NH40Ac procedure. As the pH of a soil decreased, the amount of extractable Mn increased. The relationship between the Mehlich‐1 procedure and pH was less than between the other extractants and pH.

Plant samples were collected in conjunction with the soil samples and soil Mn as determined by each method was correlated with plant concentrations. Correlations between plant Mn and soil Mn indicates that the Mehlich‐1 extractant may not be as reliable as the NH40Ac or DTPA extractants because the correlations between Mehlich‐1 extractable Mn and Mn in cotton and corn plants were poor.
Moisture Deficits and Grain Sorghum Performance: Effect of Genotype and Limited Irrigation Strategy1
Authors: Garrity Dennis P. , Watts Darrell G. , Sullivan Charles Y. , Gilley James R.
Published: July 2010

The response of three selected sorghum [Sorghum bicolor (L.) Moench] hybrids to a wide range of timings and intensities of drought stress were studied in field experiments on a sandy soil (Typic Ustipsament) in west central Nebraska. A modified line source sprinkler irrigation gradient was used to create the treatments.

Yield reductions (41 to 45%) resulting from the gradual intensification of stress over the entire season were large but very similar among genotypes. Greater genotypic differences occurred in treatments in which irrigation was limited during only one or two growth periods

The genotypic rankings for yield were quite consistent over the range of treatments, with the hybrid of highest yield potential (RS 626) usually continuing to demonstrate superior yields under drought stress. The hybrid (NB 505) of lowest yield potential did not show a comparatively greater drought resistance (i.e., a lower percentage yield reduction) under severe stress.

Grain yield tended to be linearly related to seasonal net water application and to variations in the percent of the soil water deficit that was replaced each week, regardless of variety or the growth stage(s) at which irrigation was limited.

The timing of irrigation was quite critical with large differences in the response of each hybrid to the same quantity of seasonal water applied under varying strategies. The data for both years and all genotypes indicated that an optimal strategy for allocating water under limited irrigation would be to apply a constant fraction of the crop's maximum water usage each week, allowing stress to gradually and progressively intensify throughout the season. Yield reductions will occur but these will tend to be lower per unit of irrigation water saved than when irrigation is limited only in individual growth periods.
Forage Yield, Seed Weight, and Inflorescence Characteristics of Isogenic Pearl Millet Hybrids with Four Different Cytoplasms1
Authors: Hanna Wayne W.
Published: July 2010

Valuable traits that are present in the cytoplasm can be used to improve plants. Using such traits has been demonstrated with cytoplasmic‐genic male sterility. The purpose of this research was to determine if there were cytoplasmic effects due to the A1, A2, B1, or B2 cytoplasm in near‐isogenic pearl millet, Pennisetum americanum (L.) Leeke, hybrids on dry matter yield, inflorescence characteristics, days to flower, and seed set and weight. Replicated field tests were grown in 1975, 1977, 1978, and 1981 on a Fuquay soil (loamy, siliceous, thermic arenic Plinthic Paleudults). Differences in dry matter yields were non‐significant (P = 0.05). Plants with the B2 cytoplasm had significantly shorter inflorescences. No differences were observed in inflorescence width. The difference in days to flower was significant with 1 days being the maximum difference between cytoplasms which probably is of little economic significance. There were significant differences between cytoplasms for selfed seed set but not for openpollinated seed set indicating that differences in seed set were due to fertility restoration. ‘Tift 239D2B2’ was a better fertility restorer for the A, cytoplasm than ‘Tift 23D2B2’ was for the A2 cytoplasm. Seed weight differences were related to seed set with plants setting fewer seeds producing heavier seeds. No significant maternal or A and B line effects were detected in this study.
Fractionation of Forage Grass Carbohydrates Using Liquid (Water) Chromatography1
Authors: Fales S. L. , Holt D. A. , Lechtenberg V. L. , Johnson K. , Ladisch M. R. , Anderson A.
Published: July 2010

Because of simplicity and minimum cost, one of the most promising approaches to carbohydrate analysis uses high performance liquid chromatography (HPLC) to separate neutral sugars on cation exchange resins, with only water as the mobile phase. The purpose of this research was to evaluate this technique for the analysis of carbohydrates in forage grasses.

Stem bases from field‐grown tall fescue (Festuca arundinacea Schreb.) were sequentially extracted with 95% ethanol and de‐ionized water to remove free sugars and fructosans, respectively. The fructosan extract was hydrolized with 1.0 N H2SO4. Tall fescue leaf tissue was treated with neutral detergent and the resulting neutral detergent fiber (NDF) was treated with 1.0 N H2SO4 to remove and hydrolize hemicellulose. The neutralized extracts were chromatographed on a column containing Aminex Ql5‐S, Ca++, with water as mobile phase.

Neutral sugars identified in 95% ethanol extracts were glucose, sucrose, and fructose. Fructosan hydrolizates contained glucose and fructose, and hemicellulose hydrolizates of leaf tissue contained xylose, arabinose, and a small amount of glucose. Baseline separation of all sugars was achieved within 39 min and injections could be made every 20 min. Although retention times were longer than those obtained using other methods, ease of operation, minimum cost, and column stability over time make this technique suitable for use with automatic sampling devices and data acquisition systems.
Forage Plot Clipping Wagon to Improve Harvesting Efficiency1
Authors: Caddel J. L. , Batchelder D. G. , McLaughlin G. L.
Published: July 2010

Removing forage clippings from borders and alleys of cultivar evaluation and management trials represents a major expense for forage research. A wagon, to be attached to a self‐propelled flail‐type forage harvester, was constructed to reduce the cost of harvesting plots. Clippings from alleys and borders are blown into the wagon and dumped into a pickup truck or larger wagon for removal from the area. This piece of equipment has contributed to a substantial savings in labor involved in harvesting forage plots.
Intraspecific Variation in the External and Internal Copper Requirements of Subterranean Clover1
Authors: Reuter D. J. , Loneragan J. F. , Robson A. D. , Tranthim‐Fryer D. J.
Published: July 2010

For diagnosis of Cu deficiency in pastures based on subterranean clover (Trifolium subterraneum L.) and for the management of the Cu nutrition of animals grazing them, it is important to know the extent of intraspecific variation of subterranean clover in internal Cu requirement, response to soil Cu supply, and ability to accumulate Cu in herbage.

In the present study, three cultivars (‘Clare,’ ‘Trikkala’, and ‘Seaton Park’) representative of three major subgroups of subterranean clover were grown for 70 days (D70) on a Cu deficient soil supplied with varying rates of Cu fertilizer up to 800 µg Cu/3 kg soil (Cu800). The relationships among Cu supply, yield response, amount of Cu in herbage, and Cu concentrations in young leaves were examined.

At optimum Cu supply, all three cultivars produced similar amounts of dry matter. At Cu0 on D70, Clare, Trikkala, and Seaton Park produced 9, 26, and 30%, respectively of their maximum shoot dry matter which they reached at Cu800, Cu400, and Cu200, respectively.

At all equivalent levels of Cu supply, the shoots of Clare had lower Cu contents than did those of Trikkala and Seaton Park: the effect was relatively most marked at Cu0 where shoots of Clare had only one‐half and one‐third of the Cu in the shoots of Trikkala and Seaton Park. It is suggested that Clare had a poorer ability to obtain Cu from the soil in this experiment than did Trikkala and Seaton Park and this accounted for its poorer growth at low Cu and its greater response to higher levels of applied Cu.

By contrast with their differing external Cu requirements, the three cultivars appeared to have very similar internal Cu requirements for maximum dry matter production. Estimates of critical concentrations of Cu in the youngest open leaf at just adequate Cu supply gave values of about 3 µg Cu/g dry matter for all cultivars.
Field Study of the Fate of Fall‐Applied 15N‐Labelled Fertilizers in Three Alberta Soils1
Authors: Malhi S. S. , Nyborg M.
Published: July 2010

Fall application of N fertilizers is often less effective than spring application in increasing yields of cereal crops in portions of the Prairie Provinces of Canada. This paper reports on five field experiments (and involving three soils) using 15N‐labelled fertilizers to determine the amounts of mineral N lost over the winter by denitrification, leaching, and immobilization. The labelled N fertilizers were applied at 112 kg N ha−1in October in 1974–1975 experiments and in December in 1975–1976 experiments. The plots were sampled to a depth of 120 or 150 cm in late May. In the two 1974–1975 experiments (Malmo sicl soil), KNO3 and urea were mixed into the 0 to 12 cm depth of soil, and (NH4)2SO4 was placed in a band. Recovery of the labelled fertilizer N found in the total soil N was lowest for KNO3 (60 %), next for urea (71 %), the highest for (NH4)2SO4 (84%). The addition of 50 mm of water to the soil, which reduced the soil moisture tension of the 0 to 15 cm depth to less than 33 KPa on fall freezing, decreased the recoveries of KNO3 and urea in the total soil N to 26 and 54%, respectively. There was no leaching below the 60 cm depth. For the three fertilizers, from a 10th to a third of applied N was immobilized. In the three 1975–1976 experiments, the three soil types were, Demay 1, Malmo sicl, and Falun 1. The fertilizers were placed in bands 5 cm deep into the frozen soil. There was little loss of the labelled N from the total soil N for (NH4)2SO4, but very large losses for KNO3. As in the experiments from 1974–1975, the experiments for 1975–1976 showed no 15N below 60 cm depth for KNO3, and below 30 cm depth for (NH4)2SO4. The percent of applied N which became immobilized range from 7 to 49%, with the highest value for (NH4)3SO4 on a Malmo sicl soil. In summary, substantial losses of late fall‐applied l5N‐labelled fertilizers occurred over the winter, with field experiments that were started in 2 different years. These losses from the soil averaged 67% for KNO3 (five experiments, range of 40 to 87%), 38% for urea (two experiments, range of 29 to 46%), and 10% for (NH4)2SO4 (five experiments, range of 1 to 18%). The overwinter loss of fall‐ or winterapplied N was not through leaching, but through denitrification which apparently took place in early spring. The amount of immobilization of the labelled fertilizers varied from experiment to experiment.
Alfalfa Osmotic Potential: A Comparison of the Water‐release Curve and Frozen‐tissue Methods1
Authors: Brown P. W. , Tanner C. B.
Published: July 2010

Osmoadjustment is an important response to water deficits of some plants. The purpose of our study was to examine the suitability of two methods of osmotic potential (Ψπ) measurement for researching osmotic adjustment of alfalfa (Medicago sativa L. ‘Saranac‘). Water release curves for the top fully‐developed alfalfa leaves from different stems were generated from a series of paired leaf mass and leaf water potential (Ψ) measurements using a pressure chamber. Using leaves from the same alfalfa stem, the Ψπ determined from the water release curves were compared with psychrometer measurements on sap expressed from frozen and thawed tissue of the next three to four lower leaves on each stem. Osmotic potential of sap expressed from the thawed tissue was 2.1 to 8.9 bars lower than Ψπ obtained from water‐release curves. The Ψπ of the top leaf used for water‐release curves typically was 1 to 2 bars higher than that of the next three to four lower leaves used in the frozen‐tissue method; however, this between‐leaf Ψπ difference could account for less than 50 % of the difference between methods. The remaining difference is believed to result from production of solutes in thawed tissue by enzymatic hydrolysis of nonstructural carbohydrates because rapid changes in Ψπ were observed in the tissue following thawing. This appears to invalidate routine Ψπ measurements on alfalfa using the frozen tissue method. Unless the Ψπ changes observed in frozen and thawed tissue can be circumvented, we recommend all Ψπ be determined from alfalfa leaf water release curves.
Influence of Herbicides on Yield and Botanical Composition of Alfalfa Hay1
Authors: Dutt T. E. , Harvey R. G. , Fawcett R. S.
Published: July 2010

Perennial weeds frequently infest alfalfa (Medicago sativa L.) swards. While herbicides have been identified that control these weeds, alfalfa tolerance to these herbicides and effects on dry matter yields and botanical and chemical composition are largely unknown. Thus, field studies were conducted on a Dodgeville silt loam (Typic Argiudoll fine‐silty over clayey, mixed, mesic) soil near Mt. Horeb, Wis. in 1974 and on a Plano silt loam (Typic Argiudoll fine‐silty, mixed, mesic) soil near Verona, Wis. in 1976 to compare the effects of seven herbicides applied alone, or in combination with pronamide [N (1,1‐dimethylpropynyl)‐3,5‐dichlorobenzamide] to alfalfa swards which had been colonized with quackgrass [Agropyron repens (L.) Beauv.] and several perennial broadleaf weed species. Forage yield and botanical composition were determined. Secbumeton (2‐sec‐butylamino‐4‐ethylamino‐6‐methoxy‐s‐triazine), cyanazine {2‐[[4‐chloro‐6‐(ethylamino) ‐s‐triazin‐2‐yl] amino]‐2‐methylpropionitrile], metribuzin [4‐amino‐6‐tert‐butyl‐3‐(methylthio)‐as‐triazin‐5(4H)‐one], and S‐6044 [N‐benzyl‐N‐isopropyltrimethylacetamide / 2‐cyclopropanecar‐boxamide‐5‐(2‐chloro‐1,1‐dimethylethyl)‐1,3,4‐thiadiazole], applied to actively growing swards in the fall reduced alfalfa yields in at least one cutting or at one location during the following season. Pronamide increased the total alfalfa yield. In 1974, common dandelion (Taraxacum officinale Weber.) and hoary alyssum [Berteroa incana (L.) DC.] populations increased when quackgrass was suppressed with pronamide. None of the herbicides reduced common dandelion and hoary alyssum populations. Yellow rocket (Barbarea vulgaris R. Br.) populations were reduced by secbumeton at 1.8 kg/ha, terbacil (3‐tert‐butyl‐5‐chloro‐6‐methyluracil) at 0.9 kg/ha, metribuzin at 2.3 kg/ha, and bentazon [3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4‐(3H)‐one 2,2‐dioxide] at 1.7 kg/ha. None of the treatments increased total forage yields.
Recovery of Nitrogen and Phosphorus after 17 Years from Various Fertilizer Materials Applied to Crested Wheatgrass1
Authors: Power J. F.
Published: July 2010

Information is limited regarding duration of residual effects from different N fertilizer sources upon herbage production and N and P recovery. A field experiment was conducted for 17 years on a Temvik silt loam (fine‐silty, mixed Typic Haploborolls) at Mandan, N.D., to study the effects of 5 years of N and P fertilization upon the production of crested wheatgrass [Agropyron desertorum (Fisch. ex Link), Schult.) and upon N and P recovery during and after fertilization. Fertilizer rates were 0, 90, and 180 kg N/ha from ammonium nitrate, ammonium sulfate, calcium nitrate, or urea, and 19 or 39 kg P/ha. Dry matter production and fertilizer N recovery in aboveground herbage production were least for urea, especially at 180 kg N/ha with P, but there was little difference between the other N sources. Cumulative 17‐year dry matter production was increased about 15 Mg/ha with 90 kg N/ha, and 20 to 25 Mg/ha with 180 kg N/ha. Residual effects from calcium nitrate persisted a few years longer than from other N sources and averaged 58 % recovery of N compared to 48 % for urea. Fertilizer P recovery varied from 26.8 % when P was applied with calcium nitrate to 18.2 % with ammonium sulfate. Cumulative dry matter production was increased 4 to 5 Mg/ha in 17 years by P fertilization. Fertilization with N doubled recovery of fertilizer P. Soil pH in the surface 150 mm of soil, 5 years after fertilization ceased, varied from 6.5 with calcium nitrate to 5.5 with ammonium sulfate. Fertilizer N recovered after fertilization ceased could largely be accounted for by depletion of inorganic soil N pools that had accumulated during the fertilization period. While ammonium sulfate was being applied, inorganic N accumulated primarily as exchangeable ammonium in the surface 0.3 m. Little inorganic soil N accumulated from urea application, suggesting that much N was lost by volatilization. From all sources, 70 to 160 kg fertilizer N/ha was still immobilized in the root biomass, 5 years after fertilization ceased.
Field Evaluation of a Water Relations Model for Soybean. 11. Diurnal Fluctuations1
Authors: Jones J. W. , Zur B. , Boote K. J.
Published: July 2010

A field study was conducted on soybeans (Glycine max L. Merr. cv. Williams) growing in Arredondo fine sand, a member of the hypothermic, coated family of Typic Quartzipsamments to determine the effects of drying cycles on plant water relations for comparison with results predicted by a dynamic model. Two different drying cycle treatments were imposed on different plots during late vegetative development and mid‐to‐late pod fill stages and well irrigated plots were maintained for comparison. Every other day during each drying cycle, hourly measurements of leaf water potential, canopy carbon exchange rate (CER), and canopy transpiration were measured on dry and wet plots. During the initial phases of the drying cycles leaf water potential, transpiration, and CER followed diurnal cycles closely related to radiation flux. This response lasted for 9 and 5 days during the first and second drying cycles, respectively, when crop water deficits reached critical levels causing leaf water potentials of − 1.4 and − 1.7 MPa. After these critical time periods, midday leaf water potentials became relatively stable with time whereas transpiration and CER decreased such that diurnal fluctuations disappeared. The model was successful in simulating diurnal patterns of these variables for the crop exposed to the two drying cycles.
Alfalfa Establishment and Production with Continuous Alfalfa and Following Soybeans1
Authors: Kehr W. R. , Watkins J. E. , Ogden R. L.
Published: July 2010

Alfalfa (Medicago sativa L.) is commonly grown in rotation with other crops but land can be continuously cropped with alfalfa. The purpose of this study was to determine the stand establishment and production of alfalfa cultivars that differed in disease resistance in a continuous alfalfa cropping situation, with limited supplemental irrigation. Two alfalfa cultivar experiments were spring‐seeded in 1970 at the Nebraska Agric. Exp. Stn. Mead Field Lab. on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudoll) soil with no known prior alfalfa cropping. The area was plowed in late May 1975 after the first cutting and fallowed. Soybeans (Glycine max L. Merr.) were seeded in 1976 on subareas reserved for seeding alfalfa in 1977 and 1978, and in 1977 on the subarea reserved for seeding alfalfa in 1978. Two alfalfa experiments were spring‐seeded per year in 1976, 1977, and 1978, a foliar fungicide and a fungicide seed treatment experiment. Forage yields did not differ among foliar fungicide treatments or between ‘Arc’ and ‘Ranger’ in the year of seeding or in subsequent years. Anthracnose (caused by Colletotrichum trifolii Bain) and foliar diseases were at subeconomic levels. Stands in the year of seeding did not differ among fungicide seed treatments or between ‘Agate’ and ‘Dawson’. Anthracnose and phytophthora root rot (caused by Phytophthora megasperma Drechs) were factors in stand decline and yield reduction of susceptible cultivars after the year of seeding. Stands in the year of seeding were excellent on the same land area where alfalfa was seeded in 1970 with no known previous alfalfa cropping, after plowing the 5‐year‐old stand of alfalfa in 1975 and seeding in 1976, and after 1 or 2 years of soybeans and seeding alfalfa in 1977 and 1978, respectively. Average forage yields of the experiments seeded in 1970 were 26% higher in the year of seeding, and 40 and 35% higher in the 1st and 2nd year after seeding, respectively, than in the experiments seeded in 1976 to 1978.
Alfalfa Responses to Irrigation Treatment and Environment1
Authors: Donovan T. J. , Meek B. D.
Published: July 2010

Water management is critical for maximum production of alfalfa (Medicago sativa L.) with under irrigation resulting in loss of production and over irrigation resulting in a loss of stand. The purpose of this study was to determine the optimum irrigation rates under high evaporative demand. Growth of alfalfa was evaluated on replicated plots (6 × 6 m) established on a fine textured soil (Typic Torrifluvent, clayey over loamy, montmorillonitic, calcareous hyperthermic family) and differentially irrigated from July 1975 to January 1978. The irrigation treatments were applied at 56, 66, 75 (best estimate of Ep and 84% of pan evaporation (Ep) and described as dry, semidry, optimum and wet, respectively. Alfalfa yields increased with increase in water applied. Irrigation at 84% Ep for leaching did not enhance yield over the optimum water treatment possibly because of reduced stand from waterlogging. The protein concentration of alfalfa was higher in dry than in wet treatments in March and November. During the summer, plant temperatures in the dry treatment were up to 7 C higher than in the wet treatment.
Genetic and Hormonal Control of Shoot and Root Growth of Sorghum1
Authors: Wright S. A. , Jordan W. R. , Morgan P. W. , Miller F. R.
Published: July 2010

Sorghum [Sorghum bicolor (L.) Moench] exhibits a large degree of genetic diversity far shoot development, but diversity in root development has heen virtually unexplored. Tall and short lines of ‘kafir’ and ‘milo’ sorghum that were near‐isogenic for height were examined to determine if genes which control height also exert a similar inlluence on root growth. Lines were compared both in hydroponics and in soil‐filled (fine sandy loam, Udic Paleustalf) root chambers in the field. Since dwarfing genes in sorghum appear to mediate their response through regulation of endogenous gibberellin (GA) levels, effects of exogenous GA3 applied to the shoot were also evaluated. In the field, differences in height of approximately 1 m developed between isolines of both kafir and milo, but the taller lines also developed 25 to 39% greater leaf areas. More roots were observed in the upper 60 cm of the soil profile in chambers containing the tall isolines, but when total root numbers were normalized with leaf area there were no differences between isolines. The GA3 application to tall and 3‐dwarf milo plants in hydroponic culture stimulated internode length of both cultivars, but reduced leaf area, root length, and root volume. Shoot dry weights of the tall and short isolines were increased by 19.6 and 9.9%, respectively, by GA3 treatment, while corresponding root dry weights decreased by 20.7 and 20.4 5%. These results are inconsistent with the hypothesis that gibberellins promote both shoot and root growth in sorghum, and further suggest that the genetic control of shoot growth in sorghum is largely independent from control of root growth.
Circular Sprinkler Logger1
Authors: Regier Cecil
Published: July 2010

Center pivot sprinkler systems have come into common use throughout much of the United States, where irrigation is necessary to maintain or enhance crop yields. A device is described to locate at any time the center pivot sprinkler line with regard to fixed point and to calculate the speed that the center pivot system is traveling. The device is built from a liquid level recorder and the bottom of a 208 L (55 gallon) barrel with 36 notches cut into it. The barrel bottom is attached to the pivoting vertical water supply pipe of the center pivot. A lever rides on the notches and records each 10‐degree advance of the center pivot on the liquid level recorder.
Grain Production of Winter Wheat after Spring Freeze Injury1
Authors: Paulsen Gary M. , Heyne Elmer G.
Published: July 2010

The most extensive spring freeze reported on winter wheat (Trificum aestivum L.) in the Great Plains occurred in Kansas and adjoining states in 1981. We related magnitude of injury to prevailing temperatures and compared consequences of freeze injury in 1981 and previous years. The injury threshold nearly paralleled the 0°C isotherm during the freeze. Production losses ranged up to 85% in individual counties and averaged 62% in the affected area and 31% statewide in Kansas. Low grain production in 1981 contrasted with record production in states reporting freeze injury to winter wheat during previous years. Modeling showed record winter wheat production after spring freezes other years was associated with generally favorable conditions throughout the growing season, early development of wheat during the spring, and extraordinarily favorable conditions after the freeze. Spring freeze injury might affect winter wheat production locally, but production over large areas was frequently favored by conditions associated with localized freeze injury.
Cultivar Variation in Kentucky Bluegrass: P and K Nutritional Factors1
Authors: Mehall B. J. , Hull R. J. , Skogley C. R.
Published: July 2010

While many Kentucky bluegrass (Poa pratensis L.) cultivars have been evaluated for their capacity to produce quality turf, little is known about the contribution of nutritional factors to the variability observed between cultivars. Recognizing these nutritional characters could speed the development of turfgrasses adapted to low fertility soils. In 1978 and 1979, 15 Kentucky bluegrass cultivars of differing quality, growth pattern, and place of origin were compared for clipping production rate, leaf blade P and K content, and the resulting P and K efficiency ratio (mg dry wt./mg nutrient). Correlation coefficients between these factors and turf quality scores were determined in 1978. Field plots on an Enfield silt loam (coarse‐silty over sandy skeletal, mixed, mesic, Typic Dystrochrept) were fertilized with 4.8 g N/m2/year and mowed twice weekly at 3.8 cm. On four dates each year, clippings were weighed and analyzed for P and K. Significant differences between cultivars were obtained for all factors tested. Despite substantial variability within and between seasons some cultivars exhibited reasonable consistency in their ranking for growth and nutrient content of clippings. Turf quality scores were correlated with leaf blade P content but not with clipping growth rate. The P and K efficiency ratios, based on the nutrient content of clippings, offered some promise as an indicator of cultivar nutrient use efficiency. The value of this factor for identifying cultivars adapted to low fertility soils remains to be demonstrated.
A Reliable Method for Processing Soybean Seed for Laboratory Analysis1
Authors: Schild J. A. , Olson R.A.
Published: July 2010

Established procedures for milling soybean [Glycine max (L.) Merr.] seed entail use of solvents which can be dangerous to the user of the mill and which may cause uncertain dilutions and undesirable changes in the seed. A method for dry milling soybean seed was developed in this study to process seed material for assay, including 15N isotope ratio analysis. The method involved the use of a sealed grinding device and dry ice. The seed and ice are ground together for 2 min. The resulting meal is similar in texture and recoverability to that obtainable by grinding in a solvent, and the problem of cross contamination is minimal.
Sprinkler‐Applied and Side‐Dressed Nitrogen for Irrigated Corn Grown on Sand1
Authors: Gascho G. J. , Hook J. E. , Mitchell G. A.
Published: July 2010

abstract

Maintaining efficient N nutrition for irrigated corn (Zea mays L.) grown on deep sands is difficult due to low N supplying capabilities and leaching losses of applied N. Scheduled applications of N by the use of center‐pivot irrigation equipped with modern solution injection equipment should reduce leaching and increase N‐use efficiency. The objective of this study was to compare the efficiency of scheduled applications of N through sprinkler irrigation with the more conventional side‐dress method for maintaining N nutrition and obtaining high yields. Field experiments were conducted for 5 years on a Bonifay sand (loamy, siliceous, thermic, grossarenic, Plinthic Paleudult) using solid‐set irrigation systems. Treatments included side‐dressing, sprinkler application for 10 to 11 weeks after planting according to anticipated N needs, and combinations of the two methods, as well as, differential N rates ranging from 168 to 350 kg ha‐1. Maximum yields were obtained with approximately 280 kg N ha‐1. Scheduled sprinkler application of N did not provide better N nutrition than conventional side‐dressing. In 4 of the 5 years of the study, corn was planted in soil which had near average rainfall during the winter and some leaching rain in the early growing season. In those years, side‐dressing was equal or superior to sprinkler application; while a combination of side‐dressing young corn followed by later sprinkler applications produced the highest yields. These responses may be the result of the timing of N applications or of an improved N uptake from the banded method (side‐dressing) in comparison to a broadcast method (sprinkler application).
Peanut Growth Responses to Different Levels of Leafspot1
Authors: Teare I. D. , Shokes F. M. , Gorbet D. W. , Littrell R. H.
Published: July 2010

abstract

Peanut leafspot, a disease caused by Cercospora arachidicolaHori (early leafspot), and Cercosporidium personatum(Berk. and Curt.) Deighton (late leafspot) are the most destructive foliar pathogens of peanut (Arachis hypogaea L.) and occur each year in Florida in epidemic proportions. This research establishes a data base relating growth of 'Florunner' peanut to leafspot disease severity and can be used as an aid in evaluating other resistant lines. Five leafspot disease severity levels were applied to Florunner peanut during the 1982 growing season by spraying with five levels of chlorothalonil (tetrachloroisopthalonitrile) foliar sprays beginning 40 days after planting, and continuing on a 14 day schedule until harvest. The research was conducted at the Marianna Agricultural Research Center, on a Lucy fine sand (loamy, siliceous, thermic Arenic Paleudult). Disease severity levels were compared to peanut growth measurements of leaf area index (LAI), shoot weight (leaf and stem), root weight (lateral and tap root), sample pod weight, and total biomass during the pod fill period. Although ratings were made for early and late leafspot, late leafspot was the predominant foliar disease. The LAI, leaf weight, and lateral root weight were negatively influenced by invasion of late leafspot pathogens. A comparison of field pod yield to sample pod yield indicated that lower dosages of chlorothalonil were not effective in maintaining healthy pegs, and may have allowed early pod maturity and resulted in some shedding of pods.