bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen in the P Band for Forage Establishment1
Authors: Sheard R. W. 
Published: July 2010

AbstractBand seeding, a recommended practice for forage establishment, increases seedling growth primarily because of early P uptake. Ammonium N (NH4+) has been demonstrated to increase P uptake with several crop species. The objective of the experiments reported herein was to determine if the inclusion of N as NH4+ in the P band would result in a further increase in the seedling weight of forage species.Five field experiments were conducted on a Typic Hapludalf soil using hand placement of the fertilizer band and seed in 1 m rows of alfalfa (Medicago sativa), bird'sfoot trefoil (Lotus corniculatus), and bromegrass (Bromus inermis). Monocalcium phosphate, labelled with 32P, was placed in a band 5 cm directly below the surface placed seed with NO3‐ supplied as Ca(NO3)2 or NH4+ supplied as (NH4)2 SO4. Dry weight per plant, total uptake of P and uptake of fertilizer P were measured 5 weeks after seeding.Band seeding up to 30 kg P/ha increased seedling growth as much as five‐fold in all experiments regardless of species or soil test level for P. Consistent evidence that NH4+ was increasing the concentration and/or uptake of fertilizer P and hence the concentration and/or uptake of total P by forage species was not established. In one experiment, up to 52% greater seedling growth of alfalfa, in addition to that obtained with P alone, was obtained by including NH4+ in the band in contrast to a 20% increase with NO3‐. In a second experiment, inclusion of N in the band increased growth by 11% without a preference for the form of N. Using 32P techniques one of two experiments showed the increased growth associated with the N applications was due to enhanced fertilizer P concentration and uptake, and hence increased total P uptake resulting from including the NH4+ nitrogen in the P band. It is concluded that NH4+ in the P band is of minor importance for increasing early seedling growth of cool season forage species.
Residual Effects of Dairy Cattle Manure on Plant Growth and Soil Properties1
Authors: Lund Zane F. , Doss Basil D. 
Published: July 2010

AbstractLand spreading of dairy manure is effective both in disposing of waste and in utilizing plant nutrients in the manure. This study was conducted to determine the residual effect of manure after three annual applications at rates of 0, 22.5, 45, 90, 180, and 270 metric tons/ha were each incorporated into two soils. Plots were double‐cropped each of those 3 years with pearl millet [Pennisetum americanum (L.) K. Schum ‘Gahi I’] and rye (Secale cereale L. ‘Wren's Abruzzi’). During the residual phase of the experiment, plots were double‐cropped with rye and corn (Zea mays L. ‘Funks 5757’) for a period of 4 years. Residue from high application rates of dairy cattle manure increased yields of corn on both Dothan loamy sand (Plinthic Paleudults) and Lucedale sandy loam (Rhodic Paleudults) for 4 years after the manure was applied. On the Dothan soil high rates of manure adversely affected rye growth. Most years, the residue increased N uptake in both crops on both soils. The high rates of manure increased pH to a depth of over 100 cm on the Dothan soil. Potassium accumulated in the subsoil to the 100‐cm depth. Phosphorus was increased to the 60 to 75‐cm soil depth. Magnesium also moved into the subsoil, but there was little movement of Ca below the surface 30 cm. The effect on pH, K, P, and Mg movement was much smaller on the Lucedale soil than on the coarser‐textured Dothan soil.The high rates of manure increased soil pH and soil contents of K, Mg, and P and increased the cation exchange capacity of soils. These factors contribute toward higher crop yields on manure‐treated plots. Response to dairy manure may be measured for 4 years or more after high rates of manure applications have been stopped.
Osmotic and Specific Salt Effects on Growth of Cotton1
Authors: Thomas J. R. 
Published: July 2010

AbstractStudies of plant response to a saline environment are generally performed using nutrient culture techniques or on soils artificially salinized with a single salt or a salt mixture, usually NaCl and CaCl2. The soil is frequently irrigated to maintain a low matric suction, in contrast to the multiple salt system and variable soil water content encountered in normal field conditions. The objectives of this study were to determine the effects of seasonal changes in water availability on growth and ionic composition of cotton (Gossypium hirsutum L.) and the relative importance of water stress and ion accumulation on growth under field conditions. Plots were established on the saline and non‐saline phases of Raymondville clay loam (Vertic Calciustolls). Total soil water suction (TSWS), osmotic suction of root zone (OS), plant height, and leaf mineral composition were determined periodically on each plot through the growing season. Cotton stem elongation decreased with increasing TSWS, and ceased as TSWS approached 12 bars. Regression coefficients suggested that an increase of 1 bar in the TSWS decreased growth by 3.4 and 0.9 cm, respectively, during the 70 to 85 and the 85 to 115‐day growth periods. However, plant size differences at the same TSWS suggested that growth depression on the saline soil was related to ionic composition effects in addition to an osmotically. induced water deficit. The Ca, Mg, and Na concentration of the cotton leaves increased significantly as TSWS increased, whereas K was not affected. Consequently, the K/(Ca+Mg) ratio decreased as OS and TSWS increased. The Cl concentration of the cotton leaves increased with increasing TSWS. On day 85, the leaf Mg concentration and OS were almost equally correlated with plant size. Later in the season (115 and 128 days after planting), plant size was significantly related to the OS and Na concentration of the leaves. The results indicated that plant analyses could be used to separate the specific nutritional effects from the osmotic effects on growth in a saline environment.
N‐Source and Irrigation Effects on Nitrate Leaching1
Authors: Bauder J. W. , Montgomery B. R. 
Published: July 2010

abstractEfficiency of N fertilizer sources and N leaching below the root zone of irrigated crops are concerns of agronomists and environmentalists alike. Practical data comparing the efficacy and leaching susceptibility of various N sources are necessary for resource management and as input to current nutrient transport models. This study was conducted to evaluate the effects of N fertilizer source and irrigation management on distribution of N and on leaching of NO3−‐N within the root zone of a small‐grain crop.Undisturbed columns of Maddock fine sandy loam, a well‐drained Udorthentic Haploboroll, were ciopped to wheat (Triticum aestivum L. cv. 'Era') in a greenhouse study. Three N source, Ca(NO3)2, (NH4)2SO4, and CO(NH3)2, and a check treatment were compared in factorial combination with two irrigation levels. Nitrate and NH4+‐N concentrations in leachate were measured throughout the study. Total‐N and NO3−‐N in the soil columns were measured at harvest. Percolation from the columns was the same for all treatments. Essentially, none of the applied N leached below the rooting depth as either NH4+‐N or NO3−‐N. Maximum depth of NO3−‐N leaching, which was approximately 60 cm, occurred with Ca(NO3)2 and high volume‐low frequency irrigations. No NO3−‐N accumulated below 20 cm when (NH4)2SO4, and CO(NH2)2 were applied, followed by low volume‐high frequency irrigations. Total amount and depth of NO3−‐3‐N leached were dependent on irrigation method and N source. High volume‐low frequency irrigations leached solutes to a greater depth than did low volume‐high frequency irrigations. Contribution of N source to NO3−‐N leaching was generally CO(NH2)2≤ check<(NH4)2S04<Ca(NO3)2, although NO3‐N leaching from urea treatments may have been offset by ammonia volatilization following treatment applications. Nitrate leaching from N fertilizers under irrigation may be minimized by timely applications of ammonia based fertilizers and low volume irrigations to minimize leaching below the crop root zone.
Planting Sugarbeets to Stand when Establishment is Erratic1
Authors: Winter S. R. 
Published: July 2010

AbstractPlanting sugarbeets (Beta vulgaris L.) to stand is desirable if yields can be maintained. Low seeding rates eliminate the need to thin; however, yield and quality suffer if harvest stand is low. Sugarbeet stand establishment is erratic on the Southern High Plains. Therefore, planting to stand has been assumed to be unworkable. These studies were undertaken to determine the feasibility of planting to stand where establishment is erratic.Sugarbeets were planted to stand at a wide range of seeding rates and compared to an overplanted, handthinned check. Rows were 76‐cm apart on Pullman clay loam (fine, mixed, thermic Torrertic Paleustolls order Mollisol). Yield and harvest loss were determined on the center two rows of four‐row field plots with commercial harvesting equipment.Establishment of planted seed ranged from 31 to 63% and averaged 46%. Harvested mot yield and percent sucrose were reduced if harvest stand fell below four . More than 10.0 plants/m reduced root yield thin stands, less in thick stands, and least in near optimum stands (five to seven plants/m). Optimum seeding rate depended on establishment conditions; however, results were consistently good when planting to stand at 16.7 seeds/m of row. At this seediing rate, harvested sucrose yield ranged from 94.5 to 100.2% and averaged 97.8% of the hand‐thinned check. Thus, sugarbeets were successfully planted to stand even with low and erratic establishment. Planting sugarbeets to stand should be successful in other areas. The key to success is using a seeding rate high enough to guard against the lowest commonly expected establishment.
Root Length Measurement with a Computer‐Controlled Digital Scanning Microdensitometer1
Authors: Voorhees W. B. , Carlson V. A. , Hallauer E. A. 
Published: July 2010

AbstractRoot length measurements are often neglected in research because of the time and labor involved. A technique is described that greatly facilitates measuring root length using a computer‐controlled digital scanning microdensiometer. This equipment systemically scans a photographic image of the roots and assigns numerical values to the light brightness from small areas of the image. These digitized light brightness values are used to determine the number of intersects between plant roots and a scanning line. The number of intersects is linearly related to root length. Resolutions of 1 µm can be obtained with photographic enlargement or microscopic lens. Calibration is obtained by scanning photographic images of known lengths of string, with a calibration regression coefficient for a linear fit > 0.98. A photographic image can be scanned three times in less than 5 sec and root length estimated with a coefficient of variation of < 5% among the three replicated scans. Computer programming, digitizer adjustment, and photographic modification can be used to adjust for different types of root systems.
Mammoth Genotypes and Tobacco Management Regimes for Reduced Production of Downstalk Tobaccos1
Authors: Wernsman E. A. , Matzinger D. F. 
Published: July 2010

AbstractDemand for flue−cured tobacco (Nicotiana tabacum L.) from basal leaf positions has decreased in recent years, and production systems which maximize higher quality, upstalk, leaf grades are needed.In this study we tested production regimes utilizing photoperiod−sensitive genotypes to prevent flowering and produce additional upstalk leaves as a substitute for discarded basal leaves.Normal and photoperiod−sensitive (mammoth) versions of four cultivars were grown in field experiments at two locations in 2 years. Apical meristems of mammoth genotypes were removed when plants had produced the same number of leaves as normal cultivars, four leaves more than normal in 1977, and two leaves more than noma1 in 1978.Mammoth genotypes allowed to produce the same leaf number as normal cultivars provided higher yields, with leaf quality equal or superior to the controls. Total alkaloids were lower than in normal cultivars in 1977, but equal in 1978. Reducing sugar contents were equal in both types in 1977, but significantly higher for mammoths in 1978.Permitting mammoth plants to produce four more leaves than normal, with the bottom four leaves removed from the plants and discarded, resulted in yield overcompensation with slight reductions in leaf alkaloids and increases in reducing sugars. Two additional top leaves on mammoth entries did not compensate adequately for yield reductions caused by discarding the bottom four leaves. Leaf alkaloids and sugar contents in the latter production regime did not differ from those of control cultivars.These regimes could reduce the production of downstalk tobaccos without significant yield reductions and would eliminate all premature flowering. The maintenance of apical dominance in mammoths would enhance axillary bud control.
Nodulation and N Fixation of Field‐Grown California Cowpeas as Influenced by Well‐Irrigated and Droughted Conditions1
Authors: Zablotowicz Robert M. , Focht Dennis D. , Cannell Glen H. 
Published: July 2010

AbstractThe cowpea, (Vigna unguiculata (L.) Walp.), is considered a drought‐tolerant legume. The N fixation process, however, is sensitive to water stress. This study was conducted to describe the development of nodulation and N fixation of field‐grown Californian cowpeas as influenced by stage of growth and drought. California No. 5 blackeyes were evaluated for nodulation and N fixation (as measured by acetylene reduction assay) utilizing four strains of Rhizobium sp. applied as seed inoculum. Two water regimes were utilized in this study: 1) the well‐watered regime was irrigated when the soil matric potential reached ‐0.6 bars at a depth of 20 cm, 2) the droughted regime received sufficient irrigation to allow good seed emergence, followed by a 42‐day period free of rain or irrigation. Maximum nodulation of 175 mg/plant was observed at flowering in the well‐watered plots versus 15 mg/plant in the droughted plants. Following this development stage, there was no significant difference in nodulation between water regimes. Maximum total nitrogenase activity was 22.5 and 18.8 µmoles of ethylene/plant/hour, respectively at flowering and pod‐fill in the well‐watered plants. The dry regime by contrast achieved a maximum nitrogenase activity of 5.3 and 4.5 µmoles ethylene/plant/hour at pod‐fill and pod yellowing stages of maturity, respectively. Consequently, there was a significant reduction in total nitrogenase activity (mmoles of ethylene/plant/growing season) averaged over four Rhizobium strains from 14.5 in the well‐watered to 3.7 in the droughted regime. This decrease in N fixation capacity did not decrease seed yields of droughted plants below those of well‐watered plants.
Potassium Response of Alfalfa in Solution, Sand, and Soil Culture1
Authors: Romero N. A. , Sheaffer C. C. , Malzer G. L. 
Published: July 2010

AbstractInformation on yield response to K by alfalfa (Medicago sativa L.) cultivars should be useful for determining the possibility of improving K utilization. Our objectives were to compare plant culture systems as methods of assessing K fertilization effects on alfalfa yield and K uptake, and to determine the effect of cultivar winterhardiness on yield. Growth chamber and glasshouse studies were conducted in which alfalfa cultivars were grown in sand and solution culture with nutrient solutions containing 0, 35, 60, 85, and 110 mg K/liter and in three soils receiving 0, 100, 200, 400, and 800 mg K/kg.Sand culture was not effective in evaluating potential cultivar yield differences in response to K fertilization because K levels were insufficient for plant growth. Solution culture provided a wide range of K availability which allowed for evaluation of differential yield response by cultivars. Alfalfa yields for soil culture were less than for solution culture and K additions did not produce as wide a range of herbage K concentrations as solution culture.In solution and soil cultures, cultivars differed in yield and in herbage K concentration responses to increasing K concentrations, but these responses were not related to cultivar winterhardiness. Cultivars also differed in herbage K concentrations at maximum dry matter yields and at the onset of K deficiency symptoms. Our results show that no relationship existed between cultivar winterhardiness level and yield response to K fertility. However, it may be possible to select cultivars which perform under low soil K fertility levels.
In Vitro Digestibility, Crude Protein, and Phosphorus Content of Straw of Winter Wheat, Spring Wheat, Barley, and Oat Cultivars in Eastern Montana1
Authors: White Larry M. , Hartman Glenn P. , Bergman Jerald W. 
Published: July 2010

AbstractStraw from small grains could be an important source of feed for maintenance of ruminants if its nutritive quality could be improved. This study was conducted to determine any differences in straw digestibility among and between cultivars of winter and spring wheats (Triticum aestivum L. var. aestivum, and T. turgidum L. var. durum), barley (Hordeum vulgare L.), and oats (Avena sativa L.) grown in eastern Montana. In vitro dry matter digestibility, crude protein, and P content of straw were measured on 8 to 25 cultivars of each crop for 2 years. Heading date, plant height, lodging severity, and grain yield were also determined to detect whether selecting for higher straw digestibility would adversely affect these important traits for grain production. The average in vitro digestibility of straw of winter wheat, spring wheat, barley, and oats was 36, 36, 40, and 45% the first year, and 40, 42, 47, and 45%,, respectively, the second year. Differences in straw digestibility were greater among cultivars within a crop than between crops. Straw digestibility of winter wheat, spring wheat, and barley cultivars differed by 9 and 14 percentage units, depending on crop and year. Straw of oat cultivars differed by 8 percentage units the first year but only 4 percentage units the second year. Differences in straw digestibility among crop cultivars was as great as some researchers have achieved by chemically treating the straw to improve its digestibility. Cultivars with higher straw digestibility did not have higher lodging or lower grain yield. Neither was straw digestibility consistently associated with heading date, plant height, crude protein, or P content. The first year, the average crude protein of winter wheat, spring wheat, barley, and oat straw was 2.5, 2.7, 4.4, and 3.3%, respectively; the second year, it was 2.5, 4.0, 5.9, and 5.8%, respectively. The first year, the average P content of winter wheat, spring wheat, barley, and oat straw was 0.02, 0.06, 0.15, and 0.07%, respectively; the second year, it was 0.05, 0.05, 0.09, and 0.06%, respectively.
Germination‐Temperature Profiles for Idaho and Sheep Fescue and Canby Bluegrass1
Authors: Young J. A. , Evans R. A. , Eckert R. E. , Ensign R. D. 
Published: July 2010

AbstractSheep fescue (Festuca ovina L.), Idaho fescue (F. idahoensis Elmer), and Canby bluegrass [Poa canbyi (Scribn.) Piper] are valuable forage species native on western rangelands. The success of artificial or natural revegetation of degraded or disturbed rangeland with these native species is partially dependent on understanding their germination and seedbed ecology. Germination tests were conducted at 55 regimes of constant and alternating temperatures. Constant temperatures were at 0, 2, and 5 C degree increments from 5 through 40 C. Alternating temperature regimes consisted of 16 hours in 24 at each constant temperature and 8 hours in 24 at each higher constant temperature. The germination from these 55 temperature profiles was used to construct quadratic response surfaces giving estimated percent germination with confidence intervals for each seed source tested. A series of germination profile characteristics was generated from these response surfaces to help interpret the germination response of the seeds to temperature. There were significant (P=0.01) differences in mean germination among the seed sources tested. ‘Covar’ sheep fescue had the highest mean germination, with most of the Idaho fescue sources intermediate and ‘Canbar’ Canby bluegrass lowest in germination. Covar sheep fescue was the only source tested that germinated above 76% at many temperature regimes. Most of the sources tested had maximum germination in the 51 to 75% range. Optimum germination, defined as that not lower than the maximum and its confidence interval (P=0.01), occurred around 15/20 C (15 C for 16 hours and 20 C for 8 hours) for the Idaho fescue sources but extended to lower temperatures for Covar sheep fescue and Canbar Canby bluegrass. Synthetic varieties of Idaho fescue had higher germination at warmer and more widely fluctuating temperatures than the other two species. In relation to seedbed temperatures monitored in field studies, Covar sheep fescue had the highest germination at moderate and colder‐than‐moderate seedbed temperatures. The synthetic varieties of Idaho fescue had the highest germination at warmer‐than‐moderate seedbed temperatures.
The Influence of Available Nitrate Levels on Nitrogen Fixation in Three Cultivars of Cowpea1
Authors: Miller J. C. , Scott J. S. , Zary K. W. , O'Hair S. K. 
Published: July 2010

AbstractSoil N is known to affect N2 fixation in legumes. Increased cowpea yields might be achieved by increasing N assimilation through greater symbiotic fixation, but identification of high‐fixing genotypes requires an effective screening technique. The purpose of this investigation was to determine the optimum level of supplemental N for maximum N2 fixation in cowpeas grown under greenhouse and field conditions, and the relative contributions of the measured variables on nitrogenase activity.Three cowpea cultivars were tested for N2 fixation, N2 (C2H2), under greenhouse conditions with 0, 5, 10, and 20 ppm N applied as Ca(NO3)2, and under field conditions with 0, 11.2, 22.4, and 44.8 kg/ha N applied as Ca(NO3)2. The soil was Vertic Albaqualf, fine, Montmorillonitic thermic. Nitrogenase activity decreased with increasing rates of N. Path analysis indicated that nitrate effects on N2 fixation activity were primarily on nodule mass, with the inhibition of nodule growth rather than nodule initiation. Nodule number was not a reliable predictor of N2 fixation potential of cowpea genotypes and was negatively correlated with nitrogenase activity. The results clearly indicated no advantage of applied nitrate in promoting maximum genotypic differences for N2 fixation.
Soil Clay Mineralogies in Relation to Fertility Management: Effect of Clay Mineral Types on Ammonium Fixation under Conditions of Wetland Rice Culture1
Authors: Bajwa M. I. 
Published: July 2010

AbstractTo assess the influence of soil clay mineralogy on the efficiency of normally used nitrogeneous fertilizers on soils under wetland rice (Oryza sativa L.) culture, ammonium fixation studies were carried out under hydromorphic conditions on 14 soil clays with a range of mineralogical compositions. Beidellitic and vermiculitic clays fixed more than 90% of the applied ammonium, while montmorillonitic clay fixed about 50%. Clays of all other mineralogical compositions, containing chlorite, hydrous mica, halloysite, kaolinite, and amorphous material did not fix significant amounts of ammonium. There is a need to develop management practices for soils of beidellitic and vermiculitic clay mineralogies to increase efficiency of ammonium (or ammonium‐forming) fertilizers on them through minimizing fixation.