bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental Influences on Yield and In Vitro True Digestibility of Warm‐Season Perennial Grasses and the Relationships to Fiber Components1
Authors: Henderson M. S. , Robinson D. L. 
Published: July 2010

AbstractIn recent years climatic fluctuations have been increasingly associated with seasonal variation in yield and quality of forage crops. Although considerable information is available concerning environmental influences on yield and quality of many temperate and tropical grasses, very little is known about these relationships in the major grasses grown in the southern U.S.A. The objectives of this study were to determine the relative influences of temperature (T) and photon flux density (L) on dry matter yield (DMY) and in vitro true digestibility (IVD) of four warm‐season perennial grasses grown at two soil moisture levels and to relate the differences in IVD to fiber component concentrations. Coastal and common hermudagrass [Cynodon dactylon (L.) Pers.], Pensacola hahiagrass (Paspalurn notatum Flugge), and dallisgrass (P. dilatatum Poir.) were grown in an artificial growth medium at 4 day/night temperatures (35/24, 32/21, 29/18, 26/15 C), four photon Aux densities (1,050, 840, 630, 420 µEm−2 sec−1 PAR) and two soil moisture levels in growth cabinets. After 14 and 21 days regrowth, DMY and IVD were measured. Regression equations were developed to predict DMY and IVD as functions of T and L at each soil moisture level and regrowth period.The study clearly showed that DMY of all grasses increased with increasing T and L. The imposed moisture stress sharply reduced DMY of dallisgrass (DAL) hut not of the other grasses. In all grasses IVD consistently decreased as T increased, resulting in maximum IVD at the lowest T. The effect of L on IVD ranged from positive to negative, depending on the grass and T. Maximum IVD values occurred at the high soil moisture (HM) level after 14 days regrowth. At the HM level maximum IVD of Coastal bermudagrass (COA), common hermudagrass (COM), and Pensacolabahia grass (BAH), respectively, was 5.7, 4.9, and 3.6 percentage units higher after 14 than after 21 days regrowth. In DAL at the HM level and in all grasses at the low soil moisture level, these differences due to age were only about one percentage unit or less. The Paspalum spp. averaged about seven percentage units higher in IVD than the Cynodon spp. Significant (P ≤ 0.01) negative correlations were obtained between IVD and previously reported concentrations of acid detergent fiber (ADF), cellulose, permaganate lignin (LIG), and silica in all grasses and concentrations of neutral‐detergent fiber in COA and COM. Although correlation coefficients were ≤ 0.50, hemicellulose concentration and IVD were positively correlated in all grasses. Strongest correlations were obtained between IVD and concentrations of ADF and LIG.
Effect of Irrigation and Row Spacing on Soybean Water Use1
Authors: Reicosky D. C. , Rowse H. R. , Mason W. K. , Taylor H. M. 
Published: July 2010

AbstractA better understanding of the soil‐water plant spacing interactions as they affect water‐use efficiency and crop yields requires the development of satisfactory methods for determining water use.The objective of this work was to determine the effect of 25− and 100‐cm row spacings on crop water use under irrigated and nonirrigated soybeans [Glycine max (L.) Merr.] on a fine, silty, mixed (calcareous) mesic family of Typic Udorthents soil.Water use was evaluated by measuring evapotranspiration and soil water extraction. Evapotranspiration (ET) was measured using a portable chamber that utilized psychrometric techniques to determine changes in the water vapor density when the chamber enclosed the crop canopy and the soil surface. Soil water extraction (SYVE) was calculated from changes in gravimetric water content during periods without rainfall and then corrected for the flow of water at the bottom of the root zone.Irrigation resulted in the expected higher water use rates on both row spacings. The row spacing effect early in the season was related to the leaf area index (LAI). Early in the season, the 25‐cm irrigated treatment had a slightly higher ET than the 100‐cm irrigated treatment. Later in the season, row spacing effects were not evident. The two methods employed for evaluating crop water use showed only fair agreement.
Date of Seeding, Fall Growth, and Winter Survival of Winter Wheat and Rye
Authors: Fowler D. B. 
Published: July 2010

AbstractIn the northern part of the North American Great Plains the level of cultivar winterhardiness required for winter cereal production is extremely high. Therefore, for successful production in this area close attention must be paid to all factors that influence a plant's ability to attain maximum winterhardiness. In this study, the influence of date of seeding on fall growth and winter survival of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) was assessed in seven trials grown on udic and typic boroll soils in the northcentral part of the agricultural area of Saskatchewan. In these trials, four wheat and two rye cultivars were seeded at 2 week intervals between 1 August and 15 October in each of 3 years. During this period, rye accumulated shoot dry matter at twice the rate of wheat. However, as expected, a decrease in shoot dry weight of both wheat and rye occurred with each succeeding delay in seeding date. The only meaningful winter damage that was observed in the rye was for the last two seeding dates with ‘Cougar’. The effect of date of seeding on survival of wheat was not consistent among trials. However, average survival was highest for the 15 August and 1 September seeding dates. This was 4 to 6 weeks prior to the onset of fall conditions favorable for cold acclimation. Differences in survival among wheat cultivars were not influenced by seeding date. This allowed for utilization of the Field Survival Index to evaluate the relative effects of suboptimal seeding dates on winter survival potential of cultivars. These results demonstrate that the Field Survival Index can be used to evaluate the effects of certain management practices in addition to inherent cultivar potential on winter survival.
Effect of P and K on Yield and Chemical Composition of Forage Sorghum1
Authors: Reneau R. B. , Jones G. D. , Friedericks James B. 
Published: July 2010

AbstractEven though P and K are both essential nutrients, the response of agronomic crops to P/K interaction under field conditions has not been adequately documented. This research was conducted to examine the influence of a high and low level of P over a wide range of K levels and vice versa on yield and chemical composition of forage sorghum (Sorghum bicolor L.). In Exp. I, K was applied at rates of 0, 56, 112, and 244 kg/ha and split with P application of 0 and 116 kg/ha. For Exp. II, P was applied at rates of 0,29,58, and 116 kg/ha. For Exp. II, P was applied at rates of 0, 29, 58, and 116 kg/ha and was split with K applications of 0 and 224 kg/ha. These studies were conducted from 1978 thru 1980 on a Davidson clay (Rhodic Paleudult: clayey, kaolinitic, thermic) soil. Potassium application (Exp. I) increased yields only in years with less than optimum moisture conditions and then only when P was applied. When no P was applied, yields decreased with increased K application. Phosphorus (Exp. II) increased yields for each of the 3 years studied. In years with less than optimum moisture conditions, application of K increased yields at the higher P levels. Tissue K concentrations increased with K application while Ca and Mg concentrations decreased with increased K application. However, when P was applied Ca and Mg concentration increased. In the absence of applied P, the decreased in Ca and Mg concentration was related to competition with K for uptake. This competition may be responsible for reduced yields when K application was increased in the absence of applied P. When P was applied (in the presence or absence of applied K), Ca and Mg concentration increased in the tissue. A linear relationship between yield and Mg concentration in the tissue was present.
Crop Yield – Irrigation Relationships in a Gypsiferous‐Sodic Soil1
Authors: Russo David 
Published: July 2010

AbstractThe effect of irrigation regime on the soil‐water suction, the salinity of the soil solution, and the yields of tomato (Lycopersicum esculantum var. 675) and bell pepper (Capsicum frutescens var. ‘Maor’) in a gypsiferous‐sodic soil was studied. For each of the two crops, three different amounts of water (in terms of pan evaporation) at two different irrigation frequencies (daily irrigation and irrigation every 3 days) were applied. The different irrigation regimes resulted in different soil water suction and salinity profiles, each of which can be characterized by a time average and the variance about this average. Average (over time) soil water potential (ψ) increased as both the amount of irrigation water (Q′) and the irrigation frequency (I) increased. For a given I, the ψ‐Q′ relationships can be described by a hyperbolic function. In the gypsiferous‐sodic soil used, the salinity of the soil solution was highly correlated with the exchangeable Na of the soil, which, in turn, was reduced with added irrigation water. Relative yields, Y, of the two crops were linearly dependent on the variance of the soil‐water potential, independent of the irrigation regime. This implies that the yield‐soil‐water potential relationship can be described by a quadratic function. As opposed to the unique Y‐ψ relationships, the Y‐Q′ relationships depend on the irrigation frequency. For a given Q′ yields of both crops obtained under daily irrigation were higher than the yields obtained under irrigation once in 3 days. Highest fruit yields were 126.1 Mg/ha of tomatoes and 62.7 Mg/ha of bell pepper; the respective amounts of irrigation water were 1,013 and 2,164 mm (109%) and 160% of the evaporation from a Class A pan).
Bermudagrass, Tall Fescue, and Orchardgrass Pasture Combinations with Clover or N Fertilization for Grazing Steers. I. Forage Growth and Consumption, and Animal Performance1,2
Authors: McLaren J. B. , Carlisle R. J. , Fribourg H. A. , Bryan J. M. 
Published: July 2010

AbstractInformation on pasture productivity and forage quality of various adapted species and combinations that support rapid animal gains is needed for successfully backgrounding yearling steers in the humid southeastern USA prior to feedlot placement. To evaluate productivity and quality of pasture combinations for growing beef steers, a grazing experiment was conducted near Memphis, Tenn., in 1975 to 1977 on a Typic Hapludalf. The 1.2 ha pastures were Midland (Cynodon dactylon (L.) Pers.) + (Trifolium repens L.) clover, Midland + N, 1/3 Midland + N plus 2/3 fescue (Festuca arundinacea Schreb.) + N in separate pastures, Midland overseeded with fescue + N, common (C. dactylon var. dactylon) + N, fescue + clover, and orchardgrass (Dactylis glomerata L.) + clover (OG + clo). Nitrogen was applied at 224 kg ha−1 y−1 on bermudagrass and at 67 kg ha−1 y−1 on fescue. Pastures were grazed using a modified put−and−take system maintaining orchardgrass at 7 to 14 cm high and the other grasses at 5 to 8 cm. Forage growth and consumption were determined by the cage−and−strip method. Yearling steers weighing 230 kg in the spring grazed 123 to 150 days; they were weighed at 21−day intervals and visual estimates of species composition were made at that time. Forage yield was 8.3 t/ha for Midland + fescue and ranged between 4.0 and 5.7 t/ha for the other treatments. Estimated forage consumption was 80% or more of the forage growth. Forage crude protein (122 to 152 g/kg) was sufficient for meeting the minimum requirements for growing 250− to 300−kg steers. Stocking rates were between 4 and 6 steers/ha. Average daily gains were about 475 to 575 g for all treatments, except for OG + clo (825 g/day). Pasture productivity ranged between 520 animal grazing days/ha for OG + clo to 1190 for Midland + fescue. The productivity of the other pastures was between 730 and 880 grazing days/ha. Daily forage dry matter (DM) intake was 5 to 7 kg/steer. Steers grazing OG + clo, fescue + clover, and Midland + N pastures had feed efficiencies of about 9 kg DM/kg gain; steers on the other treatments required 11 to 13 kg DM/ kg gain. Beef production was 321, 339, 375, 400, 416, 424, and 593 kg/ha for fescue + clover, common + N, 1/3 Midland − 2/3 fescue, Midland + clover, OG + clo, Midland + N, and Midland + fescue, respectively.
Relationship of Runoff and Soil Loss to Ground Cover of Native and Reclaimed Grazing Land1
Authors: Hofmann L. , Ries R. E. , Gilley J. E. 
Published: July 2010

AbstractVegetation cover is a dominant factor in controlling runoff and water erosion from agricultural land and an important criterion for determining adequate reclamation of strip−mined land. A simulated rainfall study was conducted near Center, N.D. to determine the relationship of ground cover factors to runoff and soil loss. The point frame technique was used to estimate vegetation cover as measured by either the first contact (first hit) of the sliding pins with live vegetation, litter, or bare soil and rock or by a similar contact of the sliding pins at the soil surface (surface hit). Artificial rainfall was applied at the rate of 46 mm/h to 4.0 × 22.1 m runoff plots located on 9 to 12% slopes within reclaimed and unmined pastures. Reclaimed treatments were ungrazed or grazed at light, moderate, or heavy intensity plus vegetation and litter removed by burning. Native range treatments were ungrazed, closely grazed, and burned. Native ungrazed plots had greater live surface cover than ungrazed or lightly grazed reclaimed plots but similar soil loss, runoff, and soil loss/runoff ratio (SL/RO). Best fit techniques revealed some cover factors linearly related to soil loss, runoff, and SL/RO; others logarithmically related. Live surface cover estimates were poorly related to runoff and soil loss. Adequacy of soil protection can be best estimated by percentage of bare soil. Runoff or soil loss estimates were similar whether total cover was estimated by surface hits or first hits; however, surface hits were easier to determine in tall vegetation under windy conditions. The point frame technique is satisfactory for estimating whether the cover is adequate to maintain soil stability on reclaimed land or native range. Its use can be extended to estimate ground cover in other erosion studies.
The Photoperiod Sensitive Interval in Maize1
Authors: Kiniry J. R. , Ritchie J. T. , Musser R. L. , Flint E. P. , Iwig W. C. 
Published: July 2010

AbstractIn order to apply photoperiodic response functions developed in controlled environments to field grown maize (Zea mays L.), the timing of photoperiod sensitivity must be known. The timing of photoperiod sensitivity is also necessary for defining effective photoperiods for determining the effect of latitude and planting date on development of photoperiod‐ sensitive maize cultivars. The objective of this study was to determine the time when maize is sensitive to photoperiod. Two photoperiod sensitive cultivars of maize were grown in controlled environment chambers at the Duke Univ. Phytotron in photoperiods of 10, 12.5, 15, and 17.5 h. A third cultivar was grown in 12.5 and 17.5 h photoperiods. Plants were moved at different times between chambers having different photoperiods. Time from seedling emergence to tassel emergence was recorded. The length of this development interval was compared to the same interval for control plants that remained in a constant photoperiod for the entire time. The timing of photoperiod sensitivity was determined by knowing when the plants were moved and assessing which photoperiod affected them. Plants were insensitive to photoperiod immediately after seedling emergence. They remained insensitive until 4 to 8 days prior to the date of tassel initiation in short photoperiods. The insensitive, juvenile phase, therefore ended at least 4 days prior to tassel initiation in short photoperiods. The sensitivity continued until tassel initiation or shortly thereafter. The photoperiod affecting development in the field, considering the slow rate of change of photoperiod, is the value at the time of tassel initiation.
Mycorrhizae Effects on Plant Growth, Phosphorus Uptake, and N2(C2H4) Fixation in Two Alfalfa Populations1
Authors: Satterlee Larry , Melton Bill , McCaslin Bob , Miller Don 
Published: July 2010

AbstractAlkaline soils of the southwestern USA often affect phosphorus nutrition of crop plants, decreasing yield and N2‐fixation potential of alfalfa (Medicago sativa L.). The objective of this study was to determine the relationships among P fertilization, mycorrhizae inoculation, and alfalfa populations on plant growth, P concentrations in the tissue, and N2 (C2H4) fixation rate. The experiment was a pot study conducted in a shadehouse during the summer months. Soil was a Glendale clay fineloamy, mixed thermic Typic Torrifluvent with a pH of 8.5, a water extractable P level of 0.06 ppm, and sodium bicarbonate extractable P level of 5.9 ppm.Amounts of top growth and P concentration in the forage were influenced by the interactions of alfalfa populations with P fertilization levels, and the presence or absence of mycorrhizae inoculation. The unselected alfalfa population (N0) did not increase in top growth when fertilized with P but did increase in top growth when inoculated with mycorrhizae. Phosphorus concentration in the top growth of the unselected population was highest when both fertilized with P and inoculated with mycorrhizae. The selected alfalfa population (N3) increased in top growth and P concentration in the foliage when fertilized with P. Inoculation with mycorrhizae in this population produced no significant effects. None of the treatments affected N2 (C2H4 fixation rates. The results indicated some beneficial effects on alfalfa growth and P concentration in the top growth could be expected from both mycorrhizae inoculation and P fertilization in this soil, but the effect depended on genetic factors in the plants.
Corn Growth Response to Temperature and Photoperiod. III. Leaf Number1
Authors: Warrington I. J. , Kanemasu E. T. 
Published: July 2010

AbstractThe number of leaves formed on a determinate plant species such as corn (Zea mays L.) is dependent on the time between sowing and tassel initiation and on the rate of leaf production at the apical meristem. Both of these processes, and consequently leaf number, are influenced by environmental variables such as temperature and photoperiod. In a controlled‐environment study of two corn hybrids, grown over a wide range of temperature regimes from 16/6 to 38/33°C day/night, a nonlinear leaf number/temperature response was observed. Leaf number was lowest near 18/18° C and highest in the 16/6 and in the 38/33°C conditions. Because of this nonlinearity, leaf numbers observed under differential day/night temperature regimes were sometimes quite different from those observed under constant day/night temperatures but with identical mean temperatures. A leaf number/temperature response function was estimated for each of the hybrids which could be used to predict leaf number for various temperature regimes with 12‐h photoperiods. The response function was found to be in agreement with results in the literature. Differences in leaf number between the two cultivars were consistent with their maturity ranking. Leaf number increased as photoperiod increased; an average increase of 0.71 leaves per additional hour of photoperiod was found. This increase obtained under high light conditions is greater than that recorded previously for other temperate cultivars grown under long day conditions provided by low intensity day‐length extensions from incandescent lighting. Photoperiod sensitivity was not altered by temperature. The number of unexpanded leaves present at tassel initiation was almost constant under different temperature treatments despite changes in total leaf number. In contrast, this number increased when photoperiod was increased. The main ear node position altered with changes in total leaf number but was almost constant relative to the number of mature leaves present at tassel initiation under all temperature and photoperiod treatments.
Response of Soybean Cultivars to Irrigation of a Clay Soil1
Authors: Heatherly Larry G. 
Published: July 2010

AbstractNumerous investigations have shown that soybeans [Glycine max (L.) Merr.] will give a significant yield response to irrigation, especially when the supplemental water is applied during reproductive development. However, the majority of these results have been obtained with soils ranging in texture from silt loam to sandy loam. Since soybeans are frequently grown on finer‐textured soils, we conducted field experiments in 1979 and 1980 on Sharkey clay (Vertic Haplaquept, very‐fine, montmorillonitic, thermic), a soil representative of that occurring in about 3 750 000 ha of the alluvial plain of the Mississippi River. Variables included initiation of furrow irrigation at the prebloom (V), beginning of bloom (BL), beginning of pod set (PS), and beginning of pod fill (PF) stages, plus a nonirrigated (NI) treatment, and three cultivars representing Maturity Groups V (‘Bedford’), VI (‘Tracy’), and VII (‘Bragg’). Data were collected for seed yield, mature plant height, lodging, xylem pressure potential, leaf area, and seasonal soil moisture status. In the ‘wet’ year of 1979, yields from irrigated Bedford and Tracy were not significantly greater than the respective NI yields of 2754 and 3368 kg ha−1. The PF treatment of Bragg produced a yield of 3630 kg ha−1, however, and this was significantly higher than the yields of all other treatments of Bragg, as well as all treatments of Bedford. In the dry year of 1980, all irrigation treatments of all cultivars increased yields above the NI treatment, although the PF treatment yields were only about one‐half of those from PB or BL treatments, which were nearly equal. Seed yield was highest from Bragg and lowest from Bedford in all cases. Lodging was not significantly affected by any irrigation treatment. Mature plant height was significantly increased only in the BL treatment of Bedford in 1980. Measurements of xylem pressure potential, leaf area, and soil water potential in 1980 indicated that the NI plots were severely stressed; thus, response to irrigation should have been expected. These results show that irrigation of soybeans growing in a clay soil should be initiated at or near bloom in a dry year, and at any period of stress during reproductive development in a “wet” year.