bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of the Third Youngest Leaf to Estimate Leaf Area in Kentucky Bluegrass1
Authors: Eggens J. L 
Published: July 2010

AbstractPeriodic, non−destructive data on the number of leaves, tillers, and emerged rhizomes are basic to the determination of turfgrass response to stress. Although the leaf area of turfgrasses is also markedly affected by stress, it is difficult and time−consuming to obtain without injury to the herbage.To determine if the leaf measurements of a specific leaf of each plant is correlated to the same leaf measurements for all leaves of that plant, leaf measurements were made on all leaves of individual Kentucky bluegrass (Poa pratensis L.) plants subject to stress treatments of a restricted root zone, competition from plants of a different cultivar, and 4 cm mowing height. The plants were grown in vermiculite in plastic pots. Two experiments were conducted in the greenhouse while a third was conducted in a growth chamber. Leaf length measurements involving the sheath were taken from the crown while lamina length measurements were taken from the junction of the leaf blade and the leaf sheath. Blade width measurements were made midway along the lamina length for unmowed grasses and 1 cm from the junction of the leaf blade and leaf sheath for grasses mowed at 4 cm.The correlation coefficients for the leaf (sheath and blade) length (r ≥ 0.86), blade length (r ≥ 0.86), and blade width (r ≥ 0.92) of the third youngest leaf and the same measurements for the total leaf length of each shoot of ‘Birka’, ,‘Nugget’, ‘Sydsport’, and ‘Touchdown‘ were found to be highly significant. The γ values were highly significant. when the same measurements were made on Touchdown plants regularly mowed at 4 cm and on unmowed Nugget plants growing in competition with ‘A−34’ Kentucky bluegrass.Leaf measurements of the third youngest leaf can be used to estimate growth responses of Kentucky bluegrass plants which result in changes in leaf area. Blade measurements of intact turfgrass plants in a sward are useful to estimate changes in leaf area as they are easily obtained and result in little injury to the herbage.
Testing the Difference between Limiting Yields in Quadratic Fertilizer Response Curves1
Authors: Tejeda Hernan R. 
Published: July 2010

AbstractKnowledge on whether or not fertilizer respom curves have the same limiting yield is useful when comparing fertilizers and estimating their availability coefficient. A statistical procedure to test the difference between limiting yields of two quadratic response curves is presented. The test is contingent to the assumption that the estimated nutrient rates corresponding to the limiting yields are constants. Application of the procedure is illustrated when comparing rice (Oryza sativa L.) response to two sulfur‐coated ureas (SCUs) differing in solubility with split application of urea. Only the SCU with lower solubility produced a significantly larger limiting yield than split application of urea.
Reproduction of Peanuts Treated with a Cytokinin‐Containing Preparation1
Authors: Ketring D. L. , Schubert A. M. 
Published: July 2010

AbstractCytokinins are a major class of plant hormones that regulate plant growth and development. They promote cell division, delay leaf senescence, and maintain protein and chlorophyll levels in detached leaves. Cytokinin activity is high during early stages of fruit and seed development. Thus, they offer a possible means to enhance reproduction of peanuts (Arachis hypogaea L.). Cytex3 is a water‐soluble plant (algae) extract containing about 100 ppm kinetin equivalents by bioassay. Cytex was applied at rates of 0.94, 1.27, 1.88, and 3.76 ml of formulation per ma of ground area in three soil types in the field. Treatment times were: (I) early flowering stage (35 to 40 days after planting), (II) late flowering‐pegging stage (59 to 61 days after planting), and (111) both stages (I) and (II). In the initial test in 1976, 1.27 ml Cytex/m2 was applied to ‘Florunner’, ‘Starr’, and ‘Tamnut 74‘ at all treatment times. Some treatments tended to produce more kg pod/ha than the check, but there were no significant differences in yield or value. In 1977, a significant increase in yield of Tamnut 74 occurred at the 3.76 ml Cytex/m2 rate applied at Treatment time (III). In this test, the plants were sprinkler irrigated about 24 hours after spraying. This treatment‐irrigation procedure was used in 1978 to test three rates (0.94, 1.88, and 3.76 ml Cytex/m2) on reproduction of Florunner and Tamnut 74. There were no significant differences among treatments and check for yield, grade, and value of the peanuts produced. Thus far, we have been unable to obtain consistent and significant effects on reproduction of peanuts with foliar Cytex sprays.
Oxygen Uptake by Corn Roots in Flowing and Stirred Solution Cultures1
Authors: Zandstra‐Blom M. , Ben‐Asher J. , Gale J. 
Published: July 2010

AbstractA model incorporating the mechanism of the O2 uptake process as described by the Hill equation and mass flow mechanisms is given for both steady‐state and time‐dependent cases. The two versions of the model were used to study O2 uptake. Computed results of the steady‐state model indicated that the higher the water flux density the less O2 depletion there was in relation to distance from the aeration point. The hypothesis raised by these theoretical results is that availability of O2 in aqueous media may be influenced by water flux density. The objectives of this research were therefore to test the above hypothesis experimentally and to compare measured and calculated results with the time‐dependent model. The experiments were based on a hydroponic system with corn plants (Zea mays, ‘Jubilee’) placed on flowing plates. At a certain point air was pumped continuously. Measurements of O2 concentration as a function of distance from this point were taken at various velocities. The test of the second model was made in a container with a stirred‐solution culture. Calculated and experimental results for the steady‐state model agreed with each other and suggested that the flow rate of the solution is an important factor in controlling O2 concentration along the channels. For a homogenous solution (i.e., O2 concentration which is not affected by the distance from the aerated point), the time‐dependent version of this model gave satisfactory results when compared to measured values on a quantitative basis. Qualitatively, however, the agreement was not so good.
Simulating Yield Losses in Grain Sorghum due to Sorghum Downy Mildew1
Authors: Tuleen D. M. , Frederiksen R. A. 
Published: July 2010

AbstractReliable estimates of potential losses to disease enable growers to profitably manage crops. Simulation models can give unbiased loss estimates as well as determine research areas critical to the understanding of host‐parasite interactions.A model is presented for calculating yield loss in grain sorghum [Sorghum bicolor (L.) Moench] due to systemic sorghum downy mildew caused by Peronosclerospora sorghi (Weston & Uppal) Shaw. It is sensitive to plant population, disease reaction of the hybrid, and rainfall following planting. The model was developed using data sets from field experiments conducted over several years in South and Central Texas. Empirical data indicate that: 1) a low incidence of systemic infection can thin dense sorghum stands to an optimum plant density and allow healthy plants to prosper, 2) genetic resistance effectively reduces grain yield losses caused by the disease, and 3) rainfall within 4 to 7 days after planting is associated with a low incidence of sorghum downy mildew at the locations observed. Model estimates were plotted against measured crop yields using seven data sets (from field tests conducted in 1975 and 1979 at two South Texas locations). Multiple regression analysis performed on the data showed that the model simulated grain yield with acceptable precision.
Papermill Lime‐Sludge as an Alternative Liming Material1
Authors: Simson C. R. , Kelling K. A. , Liegel E. A. 
Published: July 2010

AbstractCalcitic papermill lime‐sludge, a by‐product of the kraft paper process, was evaluated as a liming material and its equivalency with dolomitic agricultural limestone determined. An incubation study involving 10 medium‐ or light‐textured Wisconsin soils demonstrated that lime‐sludge neutralizes soil acidity very rapidly. Maximum soil pH was achieved in less than 1 week after application of the lime‐sludge, while the pH of soils treated with finely‐ground agricultural limestone increased continuously throughout the 24‐week incubation period.In field trials conducted for 3 years on two different soils, corn (Zea mays L.) was followed by alfalfa (Medicago sativa L.) or birdsfoot trefoil (Lotus corniculatus L.). Both legumes responded favorably to liming but not differently to the lime‐sludge and agricultural limestone, whereas a response was not observed for corn. Yield data provided no evidence that use of the calcitic lime‐sludge created Mg stress in any tested crop. Plant tissue analyses and the absence of a yield response to soil‐applied MgSO4•7H2O supported this observation.The liming equivalency of lime‐sludge to agricultural limestone was examined under both laboratory and field conditions. Both suggested that 1 m3 of the lime‐sludge has the same liming value as 1.1 metric tons of agricultural limestone with a neutralizing index of 60 to 69. This value is considerably less than the equivalency of 1.5 yd.3 of lime‐sludge per ton of 60 to 69 agricultural limestone specified by Wisconsin Administrative Code.
Table Beet Responses to Residual and Band‐applied Phosphorus and Potassium1
Authors: Peck N. H. , MacDonald G. E. 
Published: July 2010

AbstractMany soils used for vegetable production have been heavily fertilized and, therefore, have accumulated large amounts of available P and medium amounts of available K. Fertilizer P and K applications should be adjusted to obtain the optimum plant response to residual soil P and K. Table beet plants (Beta vulgaris L.) were grown in a Honeoye fine sandy loam soil (Glossoboric Hapludalf, fine, loamy, mixed mesic) with 3 to 162 kg residual available soil P and 84 to 908 kg residual available soil K kg/ha (0 to 25 cm depth), as measured in an ammonium acetate‐acetic acid extraction solution buffered at pH 4.8. A factorial combination of banded P as concentrated superphosphate (CSP) at 0 and 70 kg P/ha, and banded K as potassium chloride (KCl) and potassium sulfate (K2SO4) at 0 and 140 kg K/ha were randomized in each of the residual soil P and K levels.Both residual soil P and K, and banded fertilizer P and K increased the root yields. Positive yield responses to soil P and K were greater than to banded P and K.There was no difference in yield between banded applications of KCl or K2SO4. The two fertilizer sources of K fertilizer changed the concentrations of some of the elements, especially Cl, S, and Mn, in leaf blades.Soil P and banded P, especially with low soil K and without banded K, increased the concentration of P in the leaf blades, while soil K and banded K decreased the concentration of P in the leaf blades. Soil K and banded K increased the concentration of K in leaf blades while soil P and banded P decreased the concentration of K in the leaf blades. The concentration of K in leaf blades at midseason, especially in plants grown with banded P, was a good predictor of yield of roots at harvest.
A Container for Studies of Root Response to Soil‐Air Composition1
Authors: Koenig P. G. , Teague W. R. 
Published: July 2010

AbstractStudies of root response to soil‐air composition often require containers capable of isolating the root system, but not the above ground plant parts from the atmosphere. Small containers for growing plants in the atmosphere while controlling the gas composition of soil and roots were constructed from plexiglass tubing. A description of the design and methodology associated with their use is presented in this paper. Their small size allows a large number of containers to be used where space is limited and keeps gas supply requirements at low levels. The system is shown to be capable of maintaining a constant gas composition over periods of several days.
Determining the Legume‐Fraction of a Grass‐Legume Mixture by Pinitol Analysis1
Authors: Smith A. E. 
Published: July 2010

AbstractThe majority of the methods, presently used for determining the botanical composition of mixed forages, are complicated, time consuming, and seldom accurate. The increasing interest in research on grass/legume forage mixtures gives rise to the need for accurately surveying the botanical composition available to the grazing animals. The purpose of this report is to describe a simple, accurate, and rapid method for determining the legume foliage composition in a grasslegume mixture. Pinitol (l‐D‐3‐0‐methyl‐chiro‐inositol) was isolated from forage legumes, grown in the greenhouse and field plots, and determined to be unique to the Leguminosae family. Since pinitol occurs only in the legume fraction of a grass‐legume forage mixture, the legume composition is directly proportional to the pinitol concentration in the 80% ethanolic extract of the dried ground foliage mixture. Contrary to carbohydrates, pinitol concentration in legume foliage has been determined to be relatively stable over a normal daily range of environmental conditions and each stage of plant growth. The procedure was evaluated by determining the alfalfa (Medicago sativa L.) component of a greenhouse grown alfalfa‐fescue (Festuca arundinacea Schreb.) mixture over a range of concentrations and found to accurately estimate the actual legume composition (r2 = 0.989). This method could be easily adapted for use in quantifying the legume composition in animal diets collected by esophageal fistulated animals.
Effect of N Fertilizer and Corn Residue Management on Organic Matter in Minnesota Mollisols1
Authors: Bloom P. R. , Schuh W. M. , Malzer G. L. , Nelson W. W. , Evans S. D. 
Published: July 2010

AbstractTwo long‐term continuous corn (Zea mays L.) experiments were used to determine the effect of the rate of stover return on soil organic matter in high organic matter mollisols (O.C. > 2.4%). One experiment was an N rate experiment which had been cropped for 19 years. The other was a stover‐fertility management study which had been cropped for 13 years in which there were two stover management treatments: total removal and plowdown, both at high and low fertility. In the N rate experiment a 3‐ton ha−1 yr−1 difference in stover yield between the low and high N rates resulted in a 4.5% less organic carbon content for the lower N rate after 19 years. All of the treatments in the stover management study had no significant changes in organic matter content after 13 years except for the low fertility‐stover removal treatment which had 15% less organic carbon. It was concluded that for precise estimates of treatment effects on organic carbon loss in mollisols, longer treatment times are needed.
Foliar Fertilization of Dry Beans with Zn and NPKS1
Authors: Lauer D. A. 
Published: July 2010

AbstractIn response to increasing grower use of foliar fertilization, field experiments were conducted from 1977 through 1979 to evaluate the effects of Zn and NPKS foliar fertilization of dry beans (Phaseolus vulgaris L.) on nutrient concentrations in the tissue and on yield.Commercial Zn formulations of ZnSO4, ZnEDTA (Zn ethylenediamine tetraacetate), NZn and ZnPK were sprayed at growth stages ranging from early vegetative (V4) to early bloom (R1). Foliar NPKS was applied at growth stages ranging from full bloom (R2) to fully expanded seed (R7). Foliar Zn and NPKS were applied either separately or together in combination treatments.Throughout the study there was no yield increase from foliar‐applied Zn when soil Zn was adequate. There was a yield increase over the untreated check in 1978 but not in 1979. No consistent differences in bean yields were observed among ZnSO4, ZnEDTA, NZn, or ZnKP. Stage of growth at which the foliar fertilization was applied did not affect yield response.All foliar Zn treatments increased plant tissue Zn except at growth stage V4 which had insufficient foliage to intercept the spray. Similar tissue Zn cone resulted from foliar ZnSO4, ZnEDTA, and ZnKP. The NZn material, containing Zn dissolved in a solution of urea, ammonium, and nitrate N, consistently resulted in about twofold greater tissue Zn than the other Zn materials.Concentrations of N, P, K, and Zn in the bean seed were not consistently affected by foliar applications of Zn or NPKS. Even twofold to fourfold differences in whole plant Zn cone did not affect seed Zn cone.
Interrelationships of Irrigation Frequency, Urea Nitrogen, and Gypsum on Forage Sorghum Growth on a Saline Sodic Clay Soil1
Authors: Mustafa M. A. , Abdelmagid E. A. 
Published: July 2010

AbstractTwo field experiments were conducted in June, 1978, and April, 1979, at the Khartoum University Farm, Sudan, to study the effect of irrigation frequency, urea‐nitrogen, and gypsum on the yield of forage sorghum (Sorghum vulgare L.) grown on a semi‐arid, salinesodic clay soil. Each experiment had four nitrogen levels: 0N, 1N, 2N, and 3N (1N = 43.8 kg N/ha) applied as urea; three irrigation frequencies: 7, 10, and 15 days; and zero or 11.9 tonnes/ha gypsum, each replicated thrice in a split‐split plot design. The seasonal quantity of water applied was the same for all frequencies of irrigation and was slightly higher than evaporation from a U.S. class A pan.The two seasons data consistently showed that dry matter yield of the first cuts of forage sorghum increased significantly with increase in N‐level, with decrease in irrigation interval, and with gypsum application. Decreased irrigation frequency had greater effect than 3N fertilization. The benefits from gypsum application were low (5%) at the 7‐day irrigation interval. Dry matter yields were increased from 1.84 to 6.12 tonnes/ha in 1978 and from 3.20 to 7.23 tonnes/ha in 1979, by irrigating every 7 days instead of 15 days, application of 3N and 11.9 tonnes/ha gypsum.Plant height and leaf area index increased with N fertilization, with gypsum and with reduction of irrigation interval from 15 to 7 days, whereas germination percentage was significantly increased by gypsum only. Dry matter yield significantly correlated (P = 0.01) with leaf area index and plant height but not with germination percentage. Multiple regression analysis showed that the first two growth attributes accounted for about 87% of the variability of yield. The dry matter yields of the second cuts were similarly affected by treatments but were about one‐half to one‐third those of the first cuts in 1978 and 1979 seasons, respectively.For the two seasons the average seasonal water‐use was about 1.02 times that of the U.S. class A pan evaporation. Water‐use efficiency increased from 15.6 to 43.9 kg/ha‐cm in 1978 and from 19.1 to 51.2 kg/ha‐cm in 1979, by irrigating every 7 days instead of 15 days, and applying 3N urea and 11.9 tonnes/ha gypsum.
Nitrogen Production by Selected Astragalus Species1
Authors: Davis A. M. 
Published: July 2010

AbstractAstragalus species are widely distributed throughout the temperate regions, and are particularly widespread in the northern hemisphere. The genus has a poor image because of a few toxic species (loco weeds) and its contribution to nitrogen fixation and forage production has not been studied.A greenhouse experiment was conducted to determine the N‐producing capacity of six morphologically diverse Astragalus species: A. asper Jacq., A. cicer L., A. falcatus Lam., A. glycyphyllos L., A. onobrychis L., and A. ponticus Pall., and their effect on the N content of an associated grass, ‘Nordan’ crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.]. The highest concentration of N was found in A. ponticus, a robust, nonforage species. Astragalus cicer was second highest. The lowest quantity was found in A. glycyphyllos. Crested wheatgrass had the highest N content when grown in association with A. onobrychis and the lowest when grown with A. falcatus. Residual soil N was highest with A. cicer.A field study of soil N from 2‐year‐old plants of A. alpinus L., A. cicer, A. galegiformis L., A. glycyphyllos, A. odoratus Lam., and A. scorpurius Bge. resulted in a decreasing N gradient laterally from the center of the plant and with increasing depth. The highest soil N was at the 0 to 15 cm depth and 15 cm from the center of the crown. Each species tested had a different associated soil N level. Astragalus scorpurius had the highest soil N level; A. alpinus had the lowest.Sufficient variation existed in the N levels associated with native and introduced Astragalus species to warrant further investigation of their N‐fixing characteristics as well as their forage potential.
Leaf Removal to Simulate Grazing of Corn by Lambs1
Authors: Mulkey J. R. , Varner L. W. , Albach E. L. , Drawe H. J. 
Published: July 2010

AbstractMost of the corn grown in the United States is harvested for grain or silage. Only a small percent is grazed. In corn growing areas where lambs are available, corn might provide some limited grazing without affecting yield. Field experiments (Aridic calciustoll soils) were conducted during 1978–1980 to simulate the grazing of corn by lambs. The lower 2, 4, 6, 8, and 10 leaves were removed at 90 to 100% silking and at 2‐week intervals for 6 weeks thereafter. Removing the bottom 10 leaves either at 90 to 100% silking or 2 weeks afterward caused a significant reduction in grain yield, 1,000‐kernel weight and number of kernels per ha. No significant yield losses were measured with less severe defoliation or defoliation at later stages of maturity.The data showed that 890 kgha of oven‐dried forage could be removed during the first 4 weeks after 90 to 100% silking or 1,284 kg/ha after 4 weeks from silking without significant yield reductions. At the later stages, protein and P content are below the level required for proper lamb growth.These studies indicate that yield losses can be minimized by restricting leaf removal during and after pollination. However, before this can become an acceptable practice, additional investigations are needed to study the effects that lambs might have on ears, stalks, and soil compaction.