bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vegetative Establishment of Dwarf Elephantgrass: Effect of Defoliation prior to Planting Stems
Authors: Sollenberger L. E. , Jones C. S. , Albrecht K. A. , Ruitenberg G. H. 
Published: July 2010

AbstractCattle (Bos spp.) gains on ‘Mott’ dwarf elephantgrass (Pennisetum purpureum Schum.) have averaged 1 kg d−1 during 3 yr of summer grazing in Florida, but vegetative establishment of this cultivar has been problematic. The objective of this research was to determine the effect of defoliation prior to harvesting stems for vegetative planting on number of shoots produced, percentage of planted stems producing shoots, and shoot and root dry matter (DM) accumulation during 6 wk postplant. Responses were quantified for mid‐ and late summer planting dates in 2 yr on a Smyrna sand (sandy, siliceous, hyperthermic Aeric Haplaquods). Previously undefoliated plants were (i) grazed to remove 70 to 90% of leaf blade (grazed), (ii) grazed to remove the apical meristem and leaf blade of individual stems (meristem), (iii) not grazed, but leaf blades were stripped manually from stems (stripped), (iv) not grazed, but all herbage above the collar of the most recently expanded leaf was clipped manually (topped), or (v) not defoliated (undefoliated). More shoots emerged per row from undefoliated stems than from all other treatments except topped. Defoliation had no effect on percentage of planted stems that produced at least one shoot. Shoot DM was greater for undefoliated than for all but stripped stems, and root DM was greatest for undefoliated stems. Stems from the meristem treatment initiated shoot but not root growth during the first 2 wk postplant, and shoot and root DM production was low through 6 wk. Undefoliated stems produced little shoot DM by 2 wk, but root growth started soon after planting. Root and shoot growth responses were consistent with theories regarding apical dominance and auxin effects on early plant development from stem cuttings. Results suggest that successful establishment of Mott elephantgrass is most likely if undefoliated stems are planted.
Overcoming the Inflexibility of Most‐Probable‐Number Procedures
Authors: Woomer Paul , Bennett James , Yost Russell 
Published: July 2010

AbstractThe design of most‐probable‐number (MPN) experiments is restricted by the availability and completeness of tables for certain dilution ratio and replicate number combinations. The results presented in this paper are from a computer program, the Most Probable Number Enumeration System (MPNES), which generates solutions and confidence limits (P = 0.05) for population estimates of MPN data. Tables generated by MPNES agreed with existing tables yet MPNES was able to generate other tables and discrete solutions for design combinations that have not been published. The program was also used to generate population estimates from fractional base dilution ratios. The MPNES increases the accuracy of MPN estimates by decreasing the base dilution ratio, by increasing the number of replicates per dilution or by correcting for constantly inaccurate diluent volumes. The MPNES program also adjusts for inoculation volume and initial dilution ratios. In this way, MPN experiments can be designed to better measure the organism of interest rather than have the design dictated by published tables.
Responses of a Perennial Grass‐Legume Mixture to Applied Nitrogen and Differing Soil Textures
Authors: Kanyama‐Phiri G. Y. , Raguse C. A. , Taggard K. L. 
Published: July 2010

AbstractSustained productivity in multiple‐species, perennial grass‐legume pastures depends in part on achieving and maintaining an appropriate species (SP) balance. Nitrogen levels for the grass component and consistent opportunity for rooting and nodulation of new legume stolons are important. Using an outdoor pot experiment, this study investigated perennial regrowth responses of orchardgrass (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), ladino clover (Trifolium repens L.) and strawberry clover (T.fragiferum L.) to differing soil textures (ST) obtained by addition of sand and peatmoss, together with N in split applications of 60 kg ha−1 to provide rates of 60,120, and 180 kg ha−1. Of particular interest were maintenance of a favorable (e.g., 1:1) grass‐legume balance and identification of the effects of alteration in ST on legume root and nodule development (RND). The four SP were established as split plots of transplanted propagules on whole plots of N and ST treatments in a completely random design. At 30‐d intervals dry matter (DM) was sampled for each species. Legume stolons were observed for leaf appearance rate (LAR) and were subsampled once during the 120‐d experiment to determine RND. Differences in soil texture had no significant influence (P > 0.05) on DM yields or on legume LAR or RND, but significant (P < 0.001) effects on DM were observed for N and SP and for N × SP interactions. Increasing N significantly (P < 0.05) reduced LAR and RND. Percent N recovery was highest (72%) at 60 kg ha−1 N but legume dominance was avoided only at 180 kg ha−1 N, (N recovery = 12%). Successive split applications of N are useful in managing grass‐legume balance and DM yield in closely‐grazed perennial pastures, but at N levels effective in achieving these objectives a low recovery of applied N is likely.
Greenhouse Evaluation of Simulated Injected Liquid Beef Manure
Authors: Sawyer J. E. , Hoeft R. G. 
Published: July 2010

AbstractIn response to observed crop production problems (uneven growth, stunting, and chlorosis) encountered when liquid manure was knife injected into soil, a greenhouse study was initiated to detemine corn (Zea mays L.) response to simulated knife (vertical) and sweep (horizontal) placement of liquid beef manure (equivalent field application rate of 37 400 L ha−1). Derinda silt loam soil (fine, mixed mesic Typic Hapludalf), 0‐ to 20‐cm depth, was collected from a field site where crop growth problems associated with knife‐injected manure had been documented by previous field research. This soil, with and without simulated manure injections, was placed into pots and incubated at 8.9, 15.6 and 22.2 °C for 3 wks. Corn was then planted and grown for 26 d in the greenhouse. At all preplant incubation temperatures, vertical placement of the manure severely reduced plant growth throughout the duration of the study. With horizontal placement, growth was reduced early after planting, but recovered as time progressed, especially at the 22.2 °C preplant incubation temperature. Reductions in plant growth were related to toxic conditions within the manure zone. Analysis of the manure zone indicated toxicity from NH3, inferred from the high pH and high concentrations of NH+4, lowered redox potential, followed by accumulation of NO−2‐ to toxic levels. Horizontal placement resulted in reduction or elimination of these toxicities, except NO−2, which had accumulated at the end of the incubation period. Because vertical placement created a more concentrated zone of manure at the point of injection than did horizontal placement, method of injection appears to dflerentially affect potential toxic conditions and resultant plant growth.
Use of Spectral Vegetation Indices to Infer Leaf Area, Evapotranspiration and Yield: II. Results
Authors: Wiegand C. L. , Richardson A. J. 
Published: July 2010

AbstractBetter methods of interpreting spectral observations of crop canopies in terms of agronomic characteristics such as green leaf area index (L) and aboveground dry phytomass (DM), and for estimating economic yield (Y) are needed. The equations proposed were applied to single year experiments with Triticum aestivum L. and Triticum durum Desf., Gossypium hirsutum L., and Zea mays L. in order to illustrate and further test them. As predicted, fractional photosynthetically active radiation absorption (FPAR) could be estimated from vegetation indices (VI) such as perpendicular vegetation index (PVI) and the normalized difference (ND) about as well as from L. Generally, L/VI and FPAR/L‐verbalized as L as a function of VI, and FPAR as a function of L–were exponential relations whereas FPAR/VI were linear or nearly linear functions. The DM, Y, and the harvest index (Y/DM) were linearly related to PVI averaged for several dates during late vegetative development for wheat and corn, indicating that relative yields for both crops had been set by that development stage. The functional relations L/VI, FPAR/L, FPAR/VI, Y/VI, DM/VI, ∑APAR/∑VI, DM/∑APAR, Y/∑VI and (Y/DM)/VI where APAR is daily absorbed PAR (MJ m−2 d−1) presented document that direct spectral observations and the equations incorporating them do provide additional analytical tools for interpreting crop development, growth, and yield.
Influence of Planting Date, Seeding Rate, and Phosphorus Rate on Wheat Yield
Authors: Blue E. N. , Mason S. C. , Sander D. H. 
Published: July 2010

AbstractTo improve management of winter wheat (Triticum aestivum L.), more information is needed on how grain yield is influenced by planting date, seeding rate, and applied P. A 3‐yr study was conducted to measure the effects of these variables on grain yield and yield components of wheat grown in low‐P soils. All soils were Crete silty clay loams (fine Montmorillonitic mesic Pachic Argiustoll) and had Bray & Kurtz no. 1 soil tests of less than 10 mg kg−1. A randomized complete block designed experiment with a split plot treatment arrangement using three planting dates (each in 1985, 1986, and 1988) as whole plots, and factorial combinations of three seeding rates and three P rates as split plots. Grain yield, spikes meter−2, kernels spike−1, and kernel weight data were collected. Relative grain yield was greatest when 400 growing degree days (GDD, 4.4 °C base temperature) accumulated between the planting date and 31 December. Increasing the seeding rate from 34 to 101 kg ha−1 resulted in yield increases of 0.39, 0.48, and 0.21 Mg ha−1 in 1986, 1987, and 1988, respectively. Increasing the P rate from 0 to 34 kg P ha−1 resulted in 0.67, 0.53, and 0.79 Mg ha−1 yield increase in 1986, 1987, and 1988, respectively. Planting date by P rate and seeding rate by P rate interactions in 1988 indicated that P reduced the negative influence of late planting and low seeding rate on grain yield. Path coefficient analysis indicated that under conditions resulting in low tiller numbers, kernel weight contributed most in yield determination, while under high tillering conditions the number of spikes meter−2 was the most important yield component. This study showed that wheat grain yields were optimized with planting dates that allowed 400 GDD accumulation before 31 December with a 101 kg ha−1 seeding rate when available soil P is sufficient.
Effect of Fertilization Method and Tillage on Nitrogen‐15 Recovery by Corn
Authors: Timmons D. R. , Cruse R. M. 
Published: July 2010

AbstractFertilizer N utilization by corn (Zea mays L.) is influenced by different fertilizer management and tillage systems. A study was conducted in central Iowa during two consecutive years to evaluate the uptake and recovery of labeled N for continuous corn grown in two tillage systems with two fertilization methods. Tillage systems were fall moldboard‐plow and ridge‐till. Labeled N (5% 15N) as 28% urea‐ammonium nitrate solution (UAN) was either surface‐applied in the fall before any primary tillage or banded (knifed‐in) between rows at 224 kg N ha−1 just before planting. Depending on tillage and fertilization method, corn grain yields ranged from 1.3 to 7.3 Mg ha−1 which were below normal due to adverse weather conditions during the two growing seasons. The percent of plant N derived from labeled N (Nf) in the sixth leaf (50% silk) and in mature grain, stover, and whole plants was significantly lower for fall surfaceapplied 15N than for spring banded 15N. For mature whole plants, Nr ranged from 9 to 59% and averaged 53% for spring banded and 17% for fall surface‐applied 15N. Labeled N recovery by mature corn grain was affected by fertilization method and growing season and ranged from 1 to 25% during the 2‐yr period. Labeled N recovery by mature whole plants ranged from 2 to 41% and averaged four times greater for spring banded than for fall surface‐applied 15N. About 1 yr after application, an average of 20% of the 15N remained in the soil profile; and 95% of the residual 15N was found in the organic N pool. Compared with spring banded N, fall surface‐applied N was extremely inefficient for both tillage systems.
Zero Flux Plane Recession under Monocropped and Intercropped Cowpea and Sorghum
Authors: Villegas A. N. , Morris R. A. 
Published: July 2010

AbstractMovement of water remaining in the soil profile at harvest of rice (Oryza sativa L.) from puddled fields in the tropics has not been well documented. This water is used by crops during the dry season. To use it more effectively, however, its behavior during the postrice period must be better understood. Monocrops and intercrops of species differing in rooting habit [cowpea (Vigna unguiculata (L.) Walp.) and sorghum (Sorghum bicolor (L.) Moench)] were compared for effects on zero flux planes in an Andaqueptic Haplaquoll during three postrice seasons in the Philippines. Fallow treatments were included for comparison. Zero flux plane recession was regarded as an indicator of internal drainage. Zero hydraulic head gradients calculated from matric potentials defined the zero flux plane. In all years, the zero flux plane receded most rapidly under monocropped cowpea (to 0.9 m in 36—38 d after planting). The zero flux plane under the intercrop reached 0.9 m 7 d later. Recession under sorghum was less consistent, requiring 43 to 70 d to reach 0.9 m. Under fallow, it receded to about 0.45 m (to the Bt horizon) within 15 to 25 d and remained stationary except when a 30 mm rain 40 d after planting infiltrated and temporarily raised it to 0.3 m. Ten days later, the zero flux plane under fallow again was stationary at 0.45 m. In contrast, under cowpea the 30 mm rain infiltrated the soil under cowpea but was redistributed above the zero flux plane. Monocropped cowpea and the cowpea‐sorghum intercrop were equally effective at arresting drainage of residual water.
Improved Sap Flow Gauge for Woody and Herbaceous Plants
Authors: Steinberg S. L. , Van Bavel C. H. M. , McFarland M. J. 
Published: July 2010

AbstractThe internal wiring of an existing stem or trunk flow gauge was redesigned to obtain greater accuracy of the gauge itself, eliminate errors due to signal loss in connecting cables, and reduce the number of channels and of the computing required of the datalogger. Tests of the gauge conducted on bald cypress (Taxodium distichum) and Ficus retusa (L.) Nitida trees, in a greenhouse and in an urban backyard, and under well‐watered and dry conditions gave daily sap mass flow rates that were within 5% of those obtained by direct weighing.
Residual Soil Nitrogen as Affected by Continuous, Two‐Year, and Four‐Year Crop Rotation Systems
Authors: Varvel G. E. , Peterson Todd Andrews 
Published: July 2010

AbstractCrop rotation systems may reduce inorganic N fertilizer needs because of increased N mineralization, but if that N is mineralized either too early or too late with respect to crop needs, it can also be susceptible to leaching. These concerns prompted an investigation of a long‐term field study at Mead, NE on a Sharpsburg silty clay loam (fine, montmorillinitic, mesic, Typic Argiudoll) to determine effects of crop rotation and N fertilizer application on residual inorganic N levels to a depth of 150 cm after 4 yr. The study included continuous corn (Zea mays L.), continuous soybean [Glycine max (L.) Merr.], continuous grain sorghum [Sorghum bicolor (L.) Moench.], corn/soybean and grain sorghum/soybean 2‐yr rotations, and corn/oat [Avena sativa (L.)] + clover [80% yellow sweetclover [Melilotus officinalis (L.) Lam.] + 20% red clover [trifolium pratense]}/grain sorghum/soybean and corn/soybean/grain sorghum/oat + clover 4‐yr rotations with three rates of N fertilizer application. High N application resulted in greater residual NO3–N concentrations for the continuous corn and grain sorghum systems than in any of the other cropping systems to a depth of 150 cm. Residual NO3–N concentrations were low (<4 mg kg−1 at depths below 30 cm) at all N application rates in continuous soybean and 2‐ and 4‐yr cropping systems. Nitrogen removal by grain accounted for 50% of the applied N in continuous corn and grain sorghum systems at the low N application rate, but only 20 to 30% of the applied N at the high rate. Likewise, only 20 to 30% of the applied N was accounted for by N removal in the rotation systems at either N aplplication rate. Indirect results from our study suggest immobilization by crop residues and soil organic matter, not leaching, is probably most responsible for apparent N losses in these cropping systems. Although the mechanisms were not specifically identified, our results do show that crop rotations can reduce inorganic N fertilizer needs and at the same time reduce the amount of N available for leaching, both of which are important to farmers in the western Corn Belt.
Matric and Osmotic Potential Effects on Seedling Emergence at Different Temperatures
Authors: Livingston N. J. , de Jong E. 
Published: July 2010

AbstractCrop seeds and seedlings are exposed to drought, salinity and/or low soil temperatures in some areas. Therefore, the combined effects of these stresses on germination and emergence is of considerable interest. A growth room study was conducted to determine the effects of matric and osmotic potential at different temperatures on the rate and total number of seedling emergence for wheat (Triticum aestivum L. cv. Neepawa) and two rapeseed species, Polish type (Brassica campestris var. Tobin) and Argentinean type (B. napus var. Westar). Twenty‐four treatments [3 species ✕ 2 matric potentials (−0.02 and −0.2 MPa) ✕ 4 osmotic potentials (−0.03, −0.3, −0.6 and −1.2 MPa)], each replicated four times, were arranged in a completely randomized design in two insulated tanks through which water from a temperature regulated water bath was calculated. Temperature at seed depth (15 mm) was maintained at 3, 6, 12, and 15 °C in four separate experiments. In each treatment ten seeds were planted in a 300‐mL container packed with a sandy loam soil (Entic Haploborall) to give a density of 1.25 g cm−3. For all species time to 50% emergence (T50) increased with decreasing temperature. Polish rape (the smallest seed) emerged fastest at all temperatures and soil water potentials followed by Argentinean rape and then wheat (the largest seed). Differences between species generally became less pronounced with increasing temperature at all soil water potentials. for soils with the lowest matric potentials the relationship between t50, and total potential (ΨT) was linear and almost all the variability in t50, could be explained by changes in osmotic potential. Effects of ΨT on emergence were most pronounced at intermediate temperatures. Except for wheat at 3 °C, the rate of emergence at the lowest osmotic potential was significantly slower in wet soils than in dry soils so that there was significant deviation from the linear relationship between t50, and #x03A8;T, established for the dry soils. These results suggest that to avoid salt accumulation around seeds in saline soils it may be advantageous to delay seeding until the soil matric potential is low enough that water uptake by seeds is through vapor flow.
Water, Harvest Interval, and Applied Nitrogen Effects on Forage Yield of Bermudagrass and Bahiagrass
Authors: Overman A. R. , Neff C. R. , Wilkinson S. R. , Martin F. G. 
Published: July 2010

AbstractA logistic equation was used to relate forage yield to applied N for bermudagrass [Cynodon dactylon (L.) Pers.] and bahiagrass [Paspalum notatum Flugge]. It was shown that the equation could be factored into a triple product–one term each for water availability, harvest interval and applied N. The equation provides high correlation (R ≥ 0.98) between yield and applied N for all levels of water availability and harvest interval. Appropriate statistical procedures for nonlinear regression were utilized in the analysis. These results are useful for estimating effects of management factors on forage production.
Growth, Yield, and Yield Components of Lupin Cultivars
Authors: Lopez‐Bellido Luis , Fuentes Mariano 
Published: July 2010

AbstractThe cultivation of Lupin, Lupinus spp., as a protein source for animal feed and as a way of improving soil fertility is of interest for crop rotation under rainfed Mediterranean climatic conditions and poor acid soils. The adaptation of a cultivar from each one of the four cultivated species of lupin: L. albus (L.), L. luteus (L.), L. angustifolius (L.), and L. mutabilis (Sweet) has been studied. A comparative analysis of their growth (dry matter, growth rates, leaf area index (LAI) and leaf area duration (LAD), yield, yield components and harvest index (HI), protein, and fat content was carried out in the Guadalquivir Valley in southern Spain on a river terrace with Haploxeralf soil and a loamy clay texture. Variations in climatic conditions markedly influenced the duration of the different growth stages, accumulation of dry matter, leaf area and yield of the different cultivars. Lupinus albus was the species best adapted to the conditions of the survey, distributing its dry matter better and showing better growth indexes and higher grain yield. Lupinus mutabilis proved to be inadvisable for autumn sowings under the ecological conditions of the area. It was sensitive to the cold during its vegetative stage and performed poorly. The values found for the L. luteus and the angustifolius cultivars were less than those registered in other areas where it is a traditional crop. Better growth and grain yield was obtained with them when emergence was in early rather than late autumn.
Planting Date and Nitrogen Rate Effects on Spring Malting Barley
Authors: Lauer Joseph G. , Partridge Jay R. 
Published: July 2010

AbstractPlanting date (D) and N fertilizer have been shown to significantly increase spring malting barley (Hordeum vulgare L.) grain yield and protein when grown under dryland production systems where water is limiting. This study was conducted to determine D and N rate effects on grain yield, grain protein, kernel plumpness and yield components of spring malting barley grown under a production system that minimized crop water stress. Between 1984 and 1988, ‘Klages’ barley was planted at 2‐wk intervals between 15 April and 19 May (expressed as days from 1 January) at Powell, WY on a Garland clay loam (fine, mixed, mesic, Typic Haplargid). Ammonium nitrate was applied at rates of 0, 67, 134, and 202 kg N ha−1. Early planting increased kernel weight 14% and kernel density 16% compared to late planting; spike density was not affected. Increasing N from 0 to 202 kg N ha−1 increased spike density 39% and kernel density 63%; kernel weight was not affected. Grain yield decreased from 4.7 to 4.0 Mg ha−1 with later planting date and increased from 3.4 to 4.9 Mg ha−1 as N rate increased from 0 to 202 kg N ha−1 [Grain yield (Mg ha−1) = 6.92 − 0.027(D) + 0.007(N); R2 = 0.89**, significant at P = 0.011. Grain protein was unaffected by D and increased from 102 to 121 g kg−1 as N rate increased from 0 to 202 kg N ha−1 [Grain protein (g kg−1) = 127 − 0.194(0) + 0.095(N); R2 = 0.96**]. Kernel plumpness decreased from 97 to 95% with delayed D and was unaffected by N rate [Kernel plumpness (%) = 106 − 0.076(D) − 0.005(N); R2 = 0.80**]. Spring barley grain yield and kernel plumpness response to D and N rate for furrow irrigated cropping was similar to responses for dryland cropping. However, contrary to dryland results, grain protein was not affected by D when grown with minimum water stress.