bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf Photosynthetic Response to Foliar Fertilizer Applied to Corn Plants During Grain Fill1
Authors: Harder H. J. , Carlson R. E. , Shaw R. H. 
Published: July 2010

AbstractFoliar fertilization of field crops has received renewed interest as a method of increasing seed yield by supplying additional nutrients to the leaves to delay the normal depletion of nutrients in the leaves during reproductive stages. It has been hypothesized that application of foliar fertilization may delay natural leaf senescence. We tested this by estimating leaf photosynthesis in field‐grown corn (Zea mays L.) plants using a 14CO2 uptake procedure. A small segment of the leaf material enclosed in a chamber is exposed to 14CO2 for a short time period. Leaf samples are then analyzed using standard radiotracer techniques. In 1976 and 1977 14CO2 uptake rates were measured on a number of days between silking and plant maturity in conjunction with a larger experiment relating the response of corn to foliar fertilizer application and soil moisture deficits. The experimental plants were field‐grown in a Nicollet loam soil (an Aquic Hapludoll, fineloamy, mixed, mesic).These measurements indicated that the rate of leaf photosynthesis was depressed by as much as 17% the day following foliar‐fertilizer application, but had nearly recovered by the 2nd day. A similar pattern occurred in leaf conductance. No difference in the seasonal trend of photosynthetic rate was detected between control and foliarfertilizer treatments.Photosynthetic patterns after foliar‐fertilizer application may warrant further investigation, as significant yield reductions were noted in these experiments. Because the technique used in our experiments monitors rate of photosynthesis on small, intact leaf segments, totalcanopy photosynthesis and transpiration measurements could reveal helpful information.
Salt Tolerance of Two Pea Cultivars1
Authors: Cerdá A. , Caro M. , Fernández F. G. 
Published: July 2010

AbstractProduction of pea (Pisum sativum) in southeastern Spain may be limited because the waters used for irrigation are relatively poor in quality. Accordingly, this study was done to determine the salt tolerance of the pea and to compare the effects of water quality on production of pods, seed, and leaf mineral composition. Two pea cultivars were grown to maturity in lysimeters filled with a calcareous soil (Paralithic‐mollic‐Calciorthid) and irrigated with waters having ECi, values of 1.8, 4.0, 6.0, and 10.0 dS/m.The mean ECe values for the 0 to 25 cm horizon of the lysimeter soils at harvest time were approximately the same as the EC,iw of the water applied. The yields of green pods plotted as a function of ECe. manifested a yield‐ECe, function described by the equation y = 100 − B (ECe — A) where y represents the yield expressed relative to that for the lowest ECiw treatment, and B and A, the slope, and threshold ECe. value. The threshold ECe values for the SP‐290 and ‘Durana’ cultivars were respectively 2.5 and 4.5 dS/m; both cultivars exhibited the same slope value per unit decrease of ECe. at values < the threshold ECe value. Thus, the SP‐290 and Durana cultivars respectively were classified as moderately salt sensitive and moderately salt tolerant. Leaf analysis data showed a salinity treatment effect for Cl and NO3−N only, whereas cultivar effects were reflected in the Na, Ca, K, P, and total N data.The yield reduction appeared to be a function of the osmotic potential of the soil water within the rootzone (ECe although specific effects also may account in some degree.
Nitrogen and Date of Defoliation Effects on Seed Yield and Seed Quality of Tall Fescue1
Authors: Watson C. E. , Watson V. H. 
Published: July 2010

AbstractEach year approximately 150,000 to 200,000 ha of tall fescue (Festuca arundinacea Schreb.) are havested for seed in the United States. The majority of this hectarage is utilized for fall and winter grazing as well as seed production in the spring. The objectives of this study were to examine the effects of N level and date of last forage harvest in the spring on the forage and seed yield and seed quality of tall fescue.A sward of ‘Kenwell’ tall fescue was grown under three levels of N and five defoliation regimes at Mississippi State, Miss. on a Leeper silty clay loam (fine, montmorillonitic, nonacid, thermic Vertic Haplaquept). Nitrogen rates of 0, 67, and 134 kg/ha applied as NH4NO3 were applied in February of 1967 and 1968. Plots were harvested zero, one, two, three, or four times at 15 day intervals prior to seed harvest. The five defoliation treatments, by date of last forage harvest prior to seed harvest were no harvest, 15 and 30 March and 15 and 30 April. Following seed harvest the aftermath was harvested for forage. Variables measured were dry matter yield, seed yield, panicles/ m2, spikelets/panicle, and florets/spikelet. Seed quality characteristics measured included germination, seedling weight, and shoot and radicle length.Dry matter and seed yields were decreased significantly in plots defoliated later than 30 March. Reductions in seed yield appeared to be the result of decreased tiller density and the number of spikelets per panicle. Early spring defoliation (15 March) resulted in some damage to fertile tillers in the 1st year as evidenced by a reduced number of spikelets/panicle, although there was no effect on seed yield or tiller density. Seed quality was reduced for all plots defoliated after 30 March.Dry matter and seed yields increased with increasing rates of N. Maximum forage and seed yields were attained at 134 kg/ha of N while maximum seed quality was attained with 67 kg/ha of N.Results of this study indicate that tall fescue seed fields which are to be grazed or cut for hay should not be defoliated in the spring after tillers commence to elongate and become erect if maximum production is to be realized. Higher rates of N were required to maximize dry matter and seed yields than to maximize seed quality.
Concentrations of Mg, Ca, P, K, and Crude Protein in Fertilized Tall Fescue1
Authors: Reynolds J. H. , Wall W. H. 
Published: July 2010

AbstractTall fescue (Festuca arundinacea Schreb.) pastures have been implicated with the occurrence of grass tetany in the eastern U.S.A. Grass tetany problems would probably be reduced if Mg concentration in tall fescue forage were increased. The purpose of this study was to examine the effects of Mg, NPK, and N fertilizers on Mg and other major nutrients in tall fescue grown on a soil already high in Mg. A randomized complete block factorial experiment was conducted for 2 years on an Etowah silt loam (line‐loamy, siliceous, thermic, Typic Paleudults).Tall fescue was fertilized in August of 2 successive years with 0, 84, or 168 kg Mg/ha from MgSO4 . 7H2O and 67‐29‐56 or 134‐58‐112 kg N, P, K/ha from a complete NPK fertilizer; and in December with 0 or 67 kg N/ha from NH4NO3. Forage was harvested five times during the growing season and stockpiled forage was harvested in December. The Mg concentration in forage was increased by Mg and N application and was not affected by NPK rate. Calcium was decreased by N. Potassium was slightly increased by NPK fertilization.Forage Mg was above 0.20% for all sampling dates and K/(Ca + Mg) ratios were below 2.2, so the grass tetany hazard from this forage was probably low. Soil test Mg levels increased in response to Mg fertilization, but soil Mg levels were not affected by NPK or N fertilization. Temperature of the growth period had a greater influence on forage Mg than the fertilization treatments on this soil which was already high in Mg.
Irrigation, Row Spacing, and Genotype Effects on Late and Ultra‐Late Planted Soybeans1
Authors: Boerma H. R. , Ashley D. A. 
Published: July 2010

AbstractIn the southeastern United States between 25 and 40% of the soybean [Glycine max (L.) Merr.] hectarage is double‐cropped. Information on desirable production practices for double cropping soybeans after small grains, soybeans, or corn (Zea mays L.) is limited. The objectives of this study were to evaluate the effects of late (late June or early July) and ultra‐late (late July or early August) planting dates, 51‐ and 91‐cm row widths, irrigated and nonirrigated treatments, and Maturity Group VII determinate (‘Bragg’) and indeterminate (Ga76‐32 and Ga76‐18) genotypes on seed yield and other plant traits.The experiment was conducted at Plains, Ga. (32°N Lat 84°W Long) on a Greenville sandy loam (Rhodic Paleudult, clayey, kaolinitic, thermic family) soil in one dry (1978) and two intermediate rainfall seasons (1979 and 1980). Delays in planting from early July to late July resulted in an average yield reduction of 36 kg ha−1 day−1 (1.5%). In the dry season supplemental irrigation increased yield 355% (2,623 kg ha−1) in the late planting and 115% (635 kg ha−1) in the ultra‐late planting. In the intermediate rainfall seasons irrigation increased yields 38% (784 kg ha−1) for the late and 15% (190 kg ha−1) for the ultra‐late planting. The 51‐cm rows averaged 17% (278 kg ha−1) higher seed yield than the 91‐cm rows when averaged over years and all other factors. Genotypes did not differ in seed yield. The magnitude of the yield reduction from delays in planting and the high response to irrigation in dry seasons indicate the importance of intensive management to obtain maximum yields in these late‐planted environments.
Sod‐Seeding Perennial Grasses into Eastern Nebraska Pastures1
Authors: Samson John F. , Moser Lowell E. 
Published: July 2010

AbstractEastern Nebraska and neighboring areas have large amounts of depleted pastures which consist of annual bromegrasses (Bromus spp.), Kentucky bluegrass (Poa pratensis L.), and numerous broadleaf weeds. Such pastures need renovation but complete seedbed preparation is expensive and may enhance erosion. The objective of our study was to determine if sod‐seeding grasses offered an alternative to complete seedbed preparation. Three weedy pastures in southeast Nebraska on a Hastings silty clay loam (fine, montmorillonitic, mesic Udic Argiustoll), a Lamo silty clay loam [fine‐silty, mixed (calcareous), mesic Cumulic Haplaquoll], and a Geary silty clay loam (fine‐silty, mixed, mesic Udic Argiustoll) were sprayed with sod suppressing herbicides and sod‐seeded with intermediate wheatgrass [Agropyron intermedium (Host) Beauv.] or switchgrass (Panicum virgatum L.). Spring herbicide treatments consisted of atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] plus paraquat ( 1 , 1 ‘ dimethyl‐4, 4’ bypyridinium ion) broadcast and banded at 0.3 + 2.2 kg/ha, respectively, glyphosate [N‐(phosphonomethyl) glycine] broadcast and banded at 1.1 and 2.2 kg/ha, and paraquat broadcast at 0.3 or 0.6 kg/ha. In the spring experiments both intermediate wheatgrass and switchgrass were seeded. In late summer experiments the atrazine plus paraquat treatments were replaced with banded paraquat and only intermediate wheatgrass was seeded. A nonsprayed but seeded control and a seeded rototilled treatment were included at all locations and dates.Intermediate wheatgrass stands were acceptable if aboveground herbage suppression was 65% or greater during the first 6 weeks after spraying a subirrigated pasture and 80% or greater during the first 6 weeks after spraying upland pastures in the spring. In order to successfully establish switchgrass complete sod‐suppression during the first 6 weeks after spraying was required on the subirrigated pasture and 85% suppression was required on the upland pastures. Glyphosate and paraquat suppressed the sod more severely in late summer but subsequent competition with annual brome increased. Atrazine plus paraquat, or glyphosate broadcast in spring, greatly enhanced the vigor of remnant big bluestem (Andropogon gerardii Vitman) in these depleted but unplowed pastures. In some instances the existing big bluestem was dense enough to form a complete stand once the cool‐season vegetation was removed. In other situations the seeded switchgrass established around the resident big bluestem clumps.
Manganese Deficiency and Toxicity in Wheat: Influence on Growth and Forage Quality of Herbage1
Authors: Fales S. L. , Ohki K. 
Published: July 2010

AbstractThere is little information concerning critical Mn deficiency and toxicity levels in forage plants, or how plant Mn concentration affects other plant constituents associated with forage quality. This study was undertaken to investigate possible interactions between plant Mn concentration and the growth and forage quality of wheat (Triticum aestivum L. cv. Stacy).Wheat plants were grown in nutrient solution containing 0.005, 0.02, 0.05, 0.25, 1, 5, 25, 100, 200, and 500 µg/g Mn. Plants were grown for 30 days after transplanting into nutrient solution and were harvested at the three‐leaf stage, lyophilized, and weighed. Manganese concentration, in vitro dry matter disappearance (IVDMD), neutral detergent fiber (NDF), in vitro cell wall disappearance (IVCWD), total nonstructural carbohydrates (TNC), and Ca and Mg concentrations were determined on wheat shoot.Critical Mn deficiency and toxicity levels affecting normal growth of wheat shoot were determined to be 35 and 475 µg/g dry wt, respectively. These values are useful in determining deficiency and toxicity in wheat production. Percentage NDF, IVDMD, TNC, and IVCWD were reduced in tissue from plants that were critically Mn‐deficient. In vitro dry matter disappearance and TNC were increased in tissue from critically Mn‐toxic plants.In vitro dry matter disappearance ranged from 71 to 89%, with the lowest values observed for Mn‐deficient and the highest for Mn‐toxic plants. The high IVDMD of the Mn‐toxic plants appeared to be related to an accumulation of TNC, while the relatively lower IVDMD of the Mn‐deficient plants was related to reduced cell wall digestibility. Both Ca and Mg concentrations decreased as Mn concentration in the plants increased above 475 µg/g.Results of this study indicate that Mn deficiency and toxicity in wheat have a significant effect on amount of growth and the concentration of plant constituents associated with forage quality. These constituents remain relatively constant over the adequate range of Mn nutrition and plant Mn concentration should be kept within the 35 and 475 µg/g range.
Tolerances of 20 Rice Cultivars to Excess Al and Mn1
Authors: Nelson Lyle E. 
Published: July 2010

AbstractManganese toxicity is a rare occurrence in flooded or paddy rice (Oryza saliva L.); however, this is not the case for upland rice grown on aerobic soils. Although acid upland soils may contain toxic levels of both Al and Mn, cultivar tolerances to excess Al and Mn do not necessarily coincide. These studies were to determine whether a procedure could be devised for rapid screening of rice cultivars for tolerances to excess Mn and to correlate tolerances between excess Al and excess Mn. Nine rice cultivars were grown in a greenhouse for 4 weeks in nutrient solutions containing 1 µg·cm−3 and 80 µg·cm−3 Mn. The relative tolerance was expressed as a ratio of the excess Mn treatment to the optimum or control treatment using weights of plant parts, height, root length, and tiller number. These expressions of relative tolerance to excess Mn were used to rank the nine cultivars. These rankings were then compared to a ranking based on previous results obtained at IRRI when the cultivars were grown on an acid soil. Significant Spearman's rank correlation coefficients were observed between rankings for tolerance to acid soil toxicity and relative root weight (r8 = −0.93**, significant at the 0.01 level) and relative tiller number (r8 = −0.68*, significant at the 0.05 level). Other rank correlations with acid soil toxicity were not significant. Subsequently, 20 cultivars were screened for tolerance to excess Mn by growing them in a greenhouse for 4 weeks in solutions containing 0.5 and 80 µg·cm−3 Mn. These cultivars were also screened for tolerance to excess Al by growing them for 3 weeks at 3 and 30 µg·cm−3 Al. The correlation between tolerances to excess Al and Mn was tested using relative root length for Al and relative shoot weight for Mn. The correlations were not significant. Large differences in tolerance to excess Mn were observed among rice cultivars; however, it was not established that screening trials using soils containing excess amounts of available Mn can be replaced by short‐term screening in nutrient solutions. The results of this study clearly indicate that tolerance to excess Al is not necessarily correlated with tolerance to excess Mn.
Legume Establishment in Grass Sods Using Minimum‐Tillage Seeding Techniques without Herbicide Application: Forage Yield and Quality1
Authors: Taylor R. W. , Allinson D. W. 
Published: July 2010

AbstractSeedings of forages can now be made directly into existing vegetation following herbicide application. Herbicides, however, are expensive and may destroy desirable vegetation. Three field experiments were conducted on a Paxton fine sandy loam soil (coarse‐loamy, mixed, mesic Typic Dystrochrepts) to evaluate minimum‐tillage establishment of legumes in grass sods without herbicide application and to evaluate subsequent changes in forage quality. In Exp. I, alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), and crownvetch (Coronilla varia L.) were seeded into orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), smooth bromegrass (Bromus inermis Leyss.), and timothy (Phleum pratense L.) sods. Harvests were taken in 1975 through 1978 and samples obtained in 1977 and 1978 were analyzed for in vitro dry matter disappearance (IVDMD), crude protein, and mineral content. Alfalfa and birdsfoot trefoil establishment was most successful in timothy and smooth bromegrass and least successful in orchardgrass. Crownvetch failed to establish. Alfalfa mixtures produced the most dry matter, digestible dry matter, and crude protein in 1977 and 1978. Winter survival was greatest for legumes seeded in tall fescue. Experiments II and III were conducted on sites where soil pH was 6.4 and 5.6, respectively. Birdsfoot trefoil, red clover (Trifolium pratense L.), and crownvetch were directly seeded into a mixed grass‐forb sod. Vegetation was mowed for 8 weeks after seeding at either 2‐ or 4‐week intervals. Crownvetch failed to establish. Mowing frequency after seeding had little effect on legume establishment. Red clover seedings increased yields of crude protein in 1977 and digestible dry matter in 1977 and 1978. Birdsfoot trefoil did not increase digestible dry matter yields, compared to the control, until 1979 on the limed soil but increased digestible dry matter yields in 1978 on the initially unlimed soil. Results indicate that alfalfa, birdsfoot trefoil, and red clover may be successfully direct seeded into certain grass sods that have not been suppressed using herbicides.
Sugar Beet N Fertilization and Economic Optima: Recoverable Sucrose vs. Root Yield1
Authors: Adams R. M. , Farris P. J. , Halvorson A. D. 
Published: July 2010

AbstractSugar beet (Beta vulgaris L.) yields are frequently measured in terms of root yield but recoverable sucrose is the marketable product. The response of recoverable sucrose content to N fertilization differs from that of whole root yield. The rationale for this study was to compare N fertilization rates and associated returns under two decision rules: (1) fertilize to optimize recoverable sucrose yield and (2) fertilize to optimize whole root yield. Sets of response functions were estimated using both whole root yield and recoverable sucrose as measures of yield. Three years of data (1976‐1977‐1978) from the Northern Plains Soil and Water Research Center, Sidney, Mont., were used to derive these physical relationships. The estimated response functions were then combined with price and cost data to determine economically optimal N fertilization rates. Finally, returns for each optimal combination were calculated and compared. The results show substantially lower levels of N are required to optimize recoverable sucrose. Over the years of this analysis, it required approximately 90 kg less N per ha to optimize recoverable sucrose than whole root yield. More importantly, under the conditions of this analysis, producer returns would increase by an average of $460 per ha by using N rates consistent with recoverable sucrose rather than root yield. These observations suggest substantial economic benefits from use of recoverable sucrose in N fertilization decisions.
Turfgrass Growth, N Use, and Water Use under Soil Compaction and N Fertilization1
Authors: Sills M. J. , Carrow R. N. 
Published: July 2010

AbstractSoil compaction is a problem in many turf areas. In this greenhouse study the effects of soil compaction on turfgrass growth, N use, and water use were investigated. Perennial ryegrass (Lolium perenne L. ‘Pennfine’) was subjected to two compaction treatments with an 11.5 kg falling weight: a) none and b) heavy–874 J energy. Two parts of fine, montmorillonitic mesic, Aquic Argiudoll soil (Chase silt loam) was used to one part medium silica sand by volume. Fertilization rate treatments were 0.5 and 1.0 kg N/100m2. Nitrogen carrier treatments were water soluble N applied as NH4NO3 and water insoluble N applied as IBDU (isobutylidine diurea). Compaction increased bulk density, water retention, and soil strength, while decreasing aeration porosity. Visual quality, clipping yield, N use per unit area of sod, evapotranspiration, and root growth declined with compaction. Verdure, total nonstructural carbohydrates (TNC), and percent N in leaf tissue were not affected by compaction. Initial TNC levels, water use efficiency, and N use per unit area, increased as N rate increased. Clipping yield, N use per unit area, and water use efficiency were higher with a water‐soluble N carrier. Percent N in leaf tissue, early in the study, increased with water‐insoluble fertilizer. The most detrimental effects of compaction were on root weight and distribution at the high N rate. Application of high N did not compensate for the adverse effects of compaction.
Response of the Clover‐Rhizobium Symbiosis to Soil Acidity and Rhizobium Strain1
Authors: Thornton Frank C. , Davey C. B. 
Published: July 2010

AbstractThirty‐three strains of Rhizobium trifolii were tested for the effects of soil acidity on nodulation, nitrogen fixation, and dry matter production with ‘Mt. Barker’ clover (Trifolium subterraneum L.). Clover plants were grown in a Norfolk loamy sand (Typic Paleudult, fine loamy, silicious thermic) adjusted to 7, 34, and 57% Al saturation at acidity levels of pH 5.9, 5.1, and 4.4, respectively. Results from this experiment confirm that R. trifolii exhibits a large and varied tolerance to soil acidity in symbiotic association with the host. Laboratory prescreening of R. trifolii in liquid medium, based on the ability of rhizobia to grow in acid media (pH 4.2) containing Al (15 µM), identified 54% of the strains that proved symbiotically acid sensitive. Over 70% of the strains prescreened as acid tolerant ranked in the top half of all strains in total N accumulation in the most acid soil treatment. In some cases acid‐resistant effective strains of R. trifolii formed symbiotic associations that produced between 90 to 99% of the yield of the N‐amended controls.