bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Fertilizer Placement on Yield Response of Soybeans1
Authors: Ham G. E. , Nelson W. W. , Evans S. D. , Frazier R. D. 
Published: July 2010

AbstractPlacement of fertilizer in relation to the seed of most agronomic crops has been studied extensively. Limited information is available concerning the placement of fertilizer for soybeans.Fertilizer treatments consisting of banded starter, starter in contact with the seed, and a combination of banded and seed placement were superimposed on broadcast fertilizer treatments at three locations. Responses varied depending on environmental factors. With low rainfall and a low soil test P level, the largest response was from broadcast fertilizer. Starter fertilizer had less effect on seed yields either with or without broadcast fertilizer even though both starter and broadcast effects were significant. With adequate rainfall and a low P level, the largest response was to combinations of starter and broadcast fertilizer. Yields were increased by as much as 746, 598, and 941 kg/ha with band, seed placement and broadcast treatments, respectively. When P and K levels were very high, no yield increases were obtained from any fertilizer placement. In fact, seed placement without broadcast or seed placement and/or band in combination with broadcast decreased yields significantly in many cases. Three soybean [Glycine max (L.) Merrill] varieties were used at each location and the responses were different depending on varieties. The largest yield increases were obtained with ‘Corsoy’ and ‘Hark’ varieties.
Excess‐Base and Excess‐Base/Nitrogen Ratio of Various Crop Species and Parts of Plants1
Authors: Pierre W. H. , Banwart Wayne L. 
Published: July 2010

AbstractThe primary objective of this study was to determine how various crop species differ in their cation‐anion balance and thus in their effects on soil reaction and on the acidifying effects of N fertilizers on the base status of soils. Samples of 27 species of cereal, grass, legume, and miscellaneous field and vegetable crops were collected from a wide range of environmental conditions in the field. The plants were analyzed for total N, nitrate N, and excess‐base (EB); and calculations were made of excess‐base/organic N ratios (EB/N). Similar determinations were also made on the principal plant parts of 13 crop species.Marked differences were found in the excess‐base of the various crop species. The average EB ranged from 30 meq/100 g for wheat (Triticum aestivum L.) to 213 meq/100 g for tobacco (Nicotiana tabacum L.). In general, monocotyledons were lower in EB than dicotyledons. Likewise, crop species showed distinctive differences in EB/N ratios, ranging from 0.24 for cabbage (Brassica oleracea capitata) to 1.09 for buckwheat (Fagopyrum esculentum).Samples of a given crop species grown under a wide range of environmental conditions showed considerable range in EB and EB/N ratios. For most crop species the coefficients of variation of EB/N ranged from 10 to 20%.The principal plant parts of a given crop species showed in many instances moderate to large differences in EB and EB/N. Thus, differences in the proportion of plant parts in different samples may affect the EB and EB/N of a given species.The significance of the differences in the EB/N of various crop species in modifying the effect of N fertilizers on soil acidity is discussed.
Ammmonium and Nitrate Uptake by Corn (Zea mays L.) as Influenced by Nitrogen Concentration and NH+4 /NO‐3 Ratio1
Authors: Warncke D. D. , Barber S. A. 
Published: July 2010

AbstractCorn (Zea mays L.) absorbs both ammonium and nitrate forms of N. Both are usually present in the soil and some control of their proportions can be obtained by controlling nitrification. Little is known about the relative rates of absorption of these ions or their effect on plant growth rate when both are present. We investigated the effects of NH4+ and NO3− on corn by growing 13‐day‐old corn seedlings for an additional 5 days in 25 nutrient solutions consisting of 5 N concentrations (15.9, 67.1, 303, 1507, and 6015 μM) at each of 5 NH4+/NO3− ratios (8.40, 2.46, 1.05, 0.49, and 0.17). Solution NH4+, NO3−, and pH were monitored and variations kept to a minimum. Uptake rates of NH4+ and NO3− were estimated separately from solution analysis. Maximum dry matter accumulated with an N concentration of 67 μM. Maximum N uptake occurred for the combination of 303 μM N and a NH4+/NO3− ratio of 2.46. Shoot/root ratio increased significantly with increased N concentration, but was unaffected by NH4+/NO3− ratio. Above 67 μM N, the NH4+/NO3− ratio of absorbed N tended toward 1.0 as compared with the ratio in solution. There was no significant difference between NH4+ and NO3− in their relative rates of absorption. Increasing the concentration of NH4+ reduced the NO3− uptake rate and increasing the NO3− concentration reduced the NH4+ uptake rate. Each mutually influenced the absorption of the complementary nitrogen form to the same degree.
Effect of Planted Seed Size on Emergence and Yield of Soybeans (Glycine Max (L.) Merr.)1
Authors: Johnson D. R. , Luedders V. D. 
Published: July 2010

AbstractThe effect of planted seed size on emergence and yield was evaluated in the field with four soybean (Glycine max (L.) Merr.) cultivars (‘Amsoy 71’, ‘Beeson,’ ‘Calland,’ and ‘Clark 63’) in 1971 and 1972. Seed from each cultivar was divided into three sizes. These plus a mixture of all three seed sizes were tested. Seed sizes varied from 130 to 250 mg/seed and had no effect on emergence or yield. These was a significant difference among cultivars in emergence and yield, but the seed size by cultivar interaction was nonsignificant.
Yield of Alfalfa as Related to Carbon Exchange1
Authors: Delaney R. H. , Dobrenz A. K. 
Published: July 2010

AbstractPhotosynthetic rate has not proved to be an effective selection tool for forage yield in alfalfa (Medicago sativa L.). A consistantly positive correlation between yield and photosynthesis, when expressed on a leaf area and leaf weight basis, of individual plants has not been established. Since the leaf area per plant often confounds yield and carbon exchange research, this study was conducted to evaluate individual genotypes for potential total CO2 incorporation. This method of expressing photosynthesis would combine the effects of genotype variability in photosynthetic rate per unit leaf area and total leaf area per plant.Two clones which previously exhibited high photosynthetic rates and two clones with low photosynthetic rates per unit leaf area were selected from the cultivar ‘Mesa‐Sirsa’ and were transplanted into an established alfalfa field in order to obtain a normal plant population in the field experiment. Data were collected on two harvest dates. In the controlled experiment 146 plants from the alfalfa population MSE‐6 were grown in individual pots. Photosynthesis was measured at light intensities of 22 and 44 klux for two stages of growth. Dark respiration was also determined.Carbon exchange data were expressed on a leaf area, leaf dry weight, and per plant basis. Significant positive correlations were observed between photosynthesis expressed on a leaf weight and leaf area basis; however, these expressions of carbon exchange were not significantly related to total CO2 uptake per plant. Forage yield was significantly correlated (r=.96“* and .93”*, the first and second harvests, respectively) with total apparent photosynthesis per plant but not with photosynthesis expressed on a leaf weight and leaf area basis m the field study. Photosynthesis was also significantly associated with forage yield in the controlled environment experiment. Total dark respiration per plant after 25 days of regrowth was found to be highly correlated (r=.85**) forage yield. The apparent photosynthesis to dark respiration ratio was not associated with forage yield. The data from these studies suggest that the total CO2 uptake limits alfalfa forage production more than carbon exchange per unit leaf area.
Comparative Reduction of Calcium and Magnesium Composition of Corn Tissue by NH4‐N and K Fertilization1
Authors: Claassen Maria Elena , Wilcox G. E. 
Published: July 2010

AbstractAmmonium‐N nutrition in nutrient culture has been shown to reduce Ca and Mg uptake to near‐deficient levels in many plants. The addition of K to soils also reduces Ca and Mg contents of plants. Since NH4‐N is often present during the seedling growth period of plants a study was set up on soils with high and low exchangeable Ca and Mg levels to determine the comparative effect of NH4‐N and rate of K on Ca and Mg absorption by corn (Zea mays L.) plants. Knowledge of these effects could be of benefit in formulating fertilizer programs in crop production where Ca and Mg content is a factor in forage or crop quality.A greenhouse study was conducted to compare the influence of N form and K levels on the absorption of Ca and Mg by corn plants grown in Princeton sand with 67 kg Mg/ha and Fincastle silt loam with 800 kg Mg/ha. The treatments used were 100 ppm N as NH4 or NO3, and 0, 50 and 100 ppm K in factorial design. Aerial portions of the plants were analysed for N, P, K, Ca, and Mg.Increasing levels of K in the soils under NO3 nutrition reduced the concentrations of Ca and Mg in the corn tissue. However, NH4‐N at the zero K rate reduced Ca and Mg concentrations in the corn tissue to less than that at the highest K rate with NO3‐N. K rate did not significantly change Ca or Mg uptake under NH4 nutrition on either soil. The exchangeable Mg level of the soil directly affected the Mg composition of the tissue with both NO3‐N and NH4‐N nutrition. The ammonium‐N source reduced Mg uptake by corn on the soil with exchangeable Mg of 67 kg/ha to a deficient level of less than 0.20% in this tissue, which is the critical Mg level of forage associated with incidence of hypomagnesemia in ruminant animals. Thus NH4‐N must be considered an important factor in its influence on cation concentration of tissue grown on low Mg soils during periods when NH4‐N is the predominant N source.
Water Uptake by Seeds as Affected by Water Stress, Capillary Conductivity, and Seed‐Soil Water Contact. I. Experimental Study1
Authors: Hadas A. , Russo D. 
Published: July 2010

AbstractImbibition and seed germination as affected by water potentials, hydraulic conductivity, and seed‐water contact area were studied. Water potential effects Were studied under perfect seed contact and unlimited hydraulic conductivity. Effects on imbibition and germination of hydraulic conductivity and seed‐water contact were studied in an experimental setup in which separation between these factors was made possible while a very high water potential was maintained. The results show that low values of external water potential affect the rate of water uptake but not percent of germination. The rate of germination, however, is affected as long as water potential is higher than a critical value that is speciesspecific. For a given seed‐water contact area, any decrease in the hydraulic conductivity (or for a given conductivity, any reduction in contact area) reduced rates of water uptake and germination; total germination was not affected as long as the critical water potential was not reached.
Effects of Weed Control and N Fertilization at Establishment on the Growth and Nodulation of Alfalfa1
Authors: Kunelius H. T. 
Published: July 2010

AbstractThe establishment of productive alfalfa (Medicago sativa L.) stands is greatly dependent on competition by other plant species and on the seedling development of the forage legume. The objective of this study was to determine the effects of weed control methods in combination with N fertilization rate on seedling growth and nodulation of alfalfa. ‘Saranac’ alfalfa was established on check (no weed control), handweeded, and herbicide 4‐(2,4‐ dichlorophenoxy)butyric acid + 2,2‐dichloropropionic acid (2,4‐DB ‐f‐ dalapon) plots with N applied at 0, 25, 50 or 100 kg/ha at emergence of the forage legume. Dry matter (DM) yields of alfalfa in the first cutting were significantly increased by N applications of 25 to 50 kg/ha over the check in two out of three experiments. Nitrogen applied at seeding did not influence the DM yields of the second cutting. On plots treated with 2,4‐DB and dalapon, the DM yields of alfalfa in the first cutting were 30 to 81% and 11 to 78% of those of check and handweeded plots, respectively. In the second cutting, DM yields of alfalfa were not affected by the method of weed control. Weed growth was significantly increased by applied N in one experiment only.Nodule size was reduced by N applications of 50 and 100 kg/ha. Similarly, the number of nodules per plant was decreased in one experiment. Percent total N of alfalfa tissue was increased by applied N in the first cutting of two experiments. In the second cutting, high N rates resulted in a lower N content of alfalfa tissue which coincided with poor nodulation. The N rate ✕method of weed control interactions for most criteria were not statistically significant.
Physical Characteristics of Soil Mixtures Used for Golf Green Construction1
Authors: Brown K. W. , Duble R. L. 
Published: July 2010

AbstractLarge amounts of money are invested each year in the preparation of mixtures for the construction of golf greens and athletic fields. Few efforts have been made to completely characterize the physical properties of the resulting greens. Therefore, a greenhouse experiment was conducted to determine the physical characteristics of a range of sand and soil mixtures for golf green construction. Treatment variables included the amount and texture of soil used in the mixture and the presence or absence of a sand layer between the mixture and the gravel drainage layer. The mixtures were placed in 30 cm diam. containers.They were compacted and grass was established. Infiltration rates decreased after the grass was established and decreased again after the soil mixture was compacted. Mixtures with greater than 3% clay had infiltration rates too small to assure a playable surface after heavy water applications. The depth of available water held by mixtures with 5% soil averaged 6.6 cm for a 35 cm layer. Pure sands held about half this amount of water. Measured water retention agreed well with that calculated from the unsaturated conductivity of the gravel layer and the water retention characteristics of the mixture. Provided the gravel used as the drainage layer has a particle distribution such that less than half the particles are greater than 0.64 cm, little evidence of particle migration was found even without a layer of sand between the mixture and the gravel. Optimum physical characteristics were achieved with mixture containing 5% soil, 85% sand, and 10% peat moss by volume.
Varietal Response of Burley Tobacco to Stage of Physiological Development when Topped1
Authors: Gupton C. L. 
Published: July 2010

AbstractLittle is known about the effects of stage of physiological development at which the plants are topped on early vs. late flowering cultivars of burley tobacco (Nicotiana tabacum L.). Four cultivars with a range of 18 days in flowering were topped at different stages of development to determine the optimum topping date for specific cultivats, whether discrimination would exist if all cultivars were topped simultaneously, and whether or not it would be feasible to use an extremely late‐flowering cultivar commercially.Topping ‘MS Burley 37 × LS’ or ‘Burley 37’ earlier than full bloom, ‘Burley 49’ later than 50% bloom, or ‘Burley 64’ later than button stage did not increase yield significantly. Percent total N and percent total alkaloids in leaf from plots of the respective cultivars topped at these stages were within normally accepted ranges. Thus, all entries in a variety trial may be topped at the same time without creating undue bias of the estimates obtained. Maximum performance of Burley 64 was obtained when it was topped in the button stage. This indicates that a late flowering cultivar may be grown commercially if it is topped at an earlier stage of development but about the same date as early flowering cultivars.
Soil Nitrate Loss During Irrigation: Enhancement by Plant Roots1
Authors: Volz M. G. , Ardakani M. S. , Schulz R. K. , Stolzy L. H. , McLaren A. D. 
Published: July 2010

AbstractSince roots can both absorb NO‐3 and supply organic matter for NO‐3 reduction by soil microbes, the influence of a root system on NO‐3 N loss from soil solution during irrigation was studied. Two Hanford sandy loam plots (Typic Xerorthent), one fallow, and the other planted to CM‐67 barley (Hordeum vulgare L.), were ponded for 44 hours with a solution containing 100 ppm N and 46 ppm CI‐ (tracer for NO‐3) as KNO3 and CaCl2, respectively. Nitrate — N, NO‐2‐N, NH+4‐N, and Cl‐ concentrations in soil solution were determined and related to N uptake by roots and microbial transformation of NO‐3.During irrigation, concentrations of NO‐3‐N were lower in most soil solution samples from 0 to 60 cm under barley than in those from the fallow plots. However, Cl‐concentration profiles were identical in both plots to a depth of 45 cm. While nitrate uptake by barley in the top 15 cm led to some solution N loss, soil NO‐2 and NO‐2 reduction reactions are thought to have been responsible primarily, especially in deeper layers, after 26 hours. Data also indicate that, during irrigation, organic C is produced in the root zone of barley and that redox potentials in the planted plot decreased relative to those in the fallow plot. This organic C, percolating with NO‐3 solution, is thought to have facilitated NO‐3 loss both in, and below the root zone, by stimulating microbial activity and by decreasing redox potentials.
Chemical Composition and Quality of Penncross Creeping Bentgrass as Affected by Ammonium, Nitrate, and Several Fungicides1
Authors: Mazur A. R. , Hughes T. D. 
Published: July 2010

AbstractSeveral fungicides that are widely used on turfgrasses have been shown to inhibit mineralization of N in soils. The fact that most fertilizer materials commonly used on turfgrasses supply N as urea or NH4+ promoted the present investigations.Nutrient‐sand culture studies utilizing large volumes of nutrient solution with accurate control of pH and frequency and duration of wetting cycles were conducted in the greenhouse to determine the effect of NH4+ and NO3− on growth and chemical composition of ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) Greater amounts of growth were observed for plants receiving one‐half or all N as NO3−. Plants receiving NO3− as a sole source of N generally contained lesser amounts of soluble carbohydrate and greater amounts of total N than those receiving all N as NH4+.Seasonal fluctuations in growth, soluble carbohydrates, and total N were observed. Growth generally decreased during the period from April to May through October to November. Soluble carbohydrates and total N decreased during the period April to May through July to August; and increased during the period July to August through the October to November. Low soluble carbohydrate levels during July to August were attributed to respirational losses and tended to emphasize the importance of carbohydrates in N assimilation.Field studies on a Drummer silty clay loam (member of fine‐silty, mixed, mesic family of Typic Haplaquolls) did not show any differential effect of NH4+ and NO3− on turf quality or chemical composition of leaf tissue. The rapid conversion of NH4+ to NO3− undoubtedly accounted for the lack of differences under field conditions as compared to those observed in solution cultures. Fungicides were shown to influence both soluble carbohydrate levels and turf quality ratings in the field.
Effects of Narrow Row, Plant Population, and Nitrogen Application on Cotton Fiber Characteristics1
Authors: Koli Stephen E. , Morrill L. G. 
Published: July 2010

AbstractNarrow row cotton (Gossypium hirsutum L.) has shown the potential for earlier maturity. This is especially significant in areas where season length is marginal. The effect of narrow row plantings has been similar to a reduced N application rate.Studies were conducted on a Teller fine sandy loam (fine‐loamy, mixed, thermic, Udic Argiustolls) to relate the effects of N rates (0, 45, and 90 kg/ha), row spacing (25, 51, and 76 cm), and plant population (123,550 and 173,000 plants/ha) on cotton fiber characteristics. The effects of N‐row spacing and N‐population interactions were apparent. Finer fiber (decreased micronaire) resulted from high N with 25‐cm row width or high N and high population. But where no N as is applied, the 25‐cm row width produced coarser fibers. There were significant positive correlations between micronaire readings and lint and seed yields in both years.N effects on uniformity index varied from year to year. Uniformity index tended to decrease for 25‐cm row width as plant population increased and at the low plant population as row spacing increased from 25 to 76 cm. In both years there were significant correlations between uniformity index and percent pulled lint, and between uniformity index and fiber fineness.Increasing row spacing without increasing plant population, and vice versa, led to significantly lower fiber strength by 0‐inch gauge measurements in 1973. However, increasing row spacing from 25 to 76 cm produced a significant increase in fiber strength in 1974 by the 1/8‐in. gauge measurement. Fiber strength was negatively correlated with yield in 1974.The major fiber properties of length, strength, and fineness were not consistently affected by the variables of N, row spacing, and population. Some of the interacting effects are of special interest and deserve further evaluation so that the influence of climatic differences can be placed in perspective in relation to the treatment variables.
Growth Responses of Tall Fescue and Bermudagrass to Leaf Applications of Ancymidol1
Authors: Nelson C. J. , Dunn J. H. , Coutts J. H. 
Published: July 2010

AbstractGrowth inhibitors are used for topgrowth control of turfgrasses, but little information exists on associated physiological responses or growth of other plant parts. Therefore, experiments were conducted with ancymidol and an analog to assess their potential as growth retardants and their effects on physiological processes associated with vigor and tolerance to environmental stress.Tall fescue (Festuca arundinacea Schreb.) and bermudagrass [Cynodon dactylon (L.) Pers.] were grown under controlled environment conditions, and regrowth was measured for up to 32 days following application of foliar sprays of inhibitor. Topgrowth of bermudagrass was almost stopped at concentrations of ancymidol above 100 ppm, whereas tall fescue gave a quantitative growth response over the 200 to 600 ppm range. Root weight of treated bermudagrass was less than the control after a 21‐day regrowth period, but not when the growth period was 32 days. Root growth of tall fescue was not affected by treatment. Stubble weight of bermudagrass, which included leaf and stem tissue up to 6 cm above soil level, tended to be increased by treatment. Stubble weight of tall fescue was unaffected. Stolon number and weight were reduced about 50% by treatment of bermudagrass whereas tiller number of tall fescue was increased up to 30%.Concentration of storage carbohydrate was reduced 10 to 20% in stubble and stolons of treated bermudagrass, and 25 to 40% in all tissue of treated tall fescue. This probably occurred because net CO2 exchange per pot was usually reduced by treatments due to decreased leaf area. Net CO2 uptake of both species on a leaf area basis was unaffected. Water use per pot per day was 20 to 25% lower in treated plants.Results suggest that short‐term growth control may be feasible to reduce transpiration. Long term control, such as slowing growth in fall to increase frost resistance, may also be possible. However, in this study storage carbohydrate levels were lower than controls, and thus plants may not be vigorous enough to maintain themselves over long time intervals.