bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Pearl Millet Leaf Area and Specific Leaf Area
Authors: Payne W. A. , Wendt C. W. , Hossner L. R. , Gates C. E. 
Published: July 2010

AbstractLeaf area and specific leaf area (SLA) are important parameters in many agronomic and ecological processes, but can be difficult and expensive to measure. This study was made to test simplified methods of estimating pearl millet [Pennisetum glaucum (L.) R. Br.] leaf area and SLA. Leaf length, maximum width, area, and dry mass data were obtained at 2‐wk intervals from plants grown in 75‐L pots. Pots contained 85 kg of acidic, P‐deficient Betis sand (sandy, silicious, thermic Psammentic Paleustalf) and were treated with four P levels and two water treatments (stressed and nonstressed). Individual leaf area was estimated non‐destructively with the following equations: Leaf area = 0.68 ✕ (leaf length ✕ maximum width) −0.114 (R2 = 0.955) and Ln(leaf area) = 2.08 ✕ Ln(length) −3.53 (R2 = 0.939). Individual leaf area and whole plant leaf area were calculated from leaf dry mass by the following linear and nonlinear equations: Leaf area = 133.6 ✕ Leaf mass + 22.69 (R2 = 0.900), and Leaf area = 162.84 ✕ Leaf mass0.687 (R2 = 0.973). Residual errors indicated that the nonlinear equation was more accurate for area estimation of small leaves (≤0.20 g), and that leaf area data were heteroscedastic. Leaf dry mass was also used to calculate SLA by the nonlinear equation SLA = 176.7 × Leaf mass−0.216 (R2 = 0.918), which gave excellent fit to experimental data independent of harvest date, P level and watering treatment. Our results demonstrate that pearl millet leaf area and SLA can be accurately estimated and easily simulated from simple regression equations.
Pearl Millet Growth as Affected by Phosphorus and Water
Authors: Payne W. A. , Lascano R. J. , Hossner L. R. , Wendt C. W. , Onken A. B. 
Published: July 2010

AbstractThe interaction of soil water and P supply is of paramount importance to pearl millet [Pennisetum glaucum (L.) R. Br.] growth in Sahelian Africa due to unreliable rainfall and low soil P availability. This study was conducted to quantify the growth response of pearl millet to water supply and P under conditions analogous to the Sahel in terms of climate and soil. Millet was grown for 84 d in pots containing 85 kg of Betis: sand (sandy, silicious, thermic Psammentic Paleustalf) at a semiarid location near Lubbock, TX, and harvested at regular intervals. Pots were treated with four levels of applied P (0.00, 1.15, 3.38, and 7.77 g P m−2) and two water levels (water stressed and non‐water stressed). Whole plant biomass at final harvest increased within the non‐water stressed treatment from 145 g per pot in the 0.00 g P m−2 level to 626 g per pot in the 7.77 g P m−2 level, and from 64 to 220 g per pot within the water stressed treatments. Analysis of variance showed highly significant statistical interaction between water and P level during most of the experiment. Maximum whole plant production rates for non‐water stressed plants occurred between 42 and 58 days after emergence (DAE), increasing from 5.0 g d−1 in the 0.00 g P m−2 level to 18.5 g d−1 in the 7.77 g P m−2 level, and between 28 and 42 DAE for water stressed plants, increasing from 1.3 g d−1 to 8.5 g d−1. Growth rates of plant organs also increased with P level irrespective of water level. Our study quantifies the strong influence and interaction of P and water supply on pearl millet growth and development in Sahel‐like environments, and demonstrates that water supply under such conditions cannot be effectively managed for pearl millet production without addressing soil fertility constraints.
Potato Response to Legume and Fertilizer Nitrogen Sources
Authors: Griffin T. S. , Hesterman O. B. 
Published: July 2010

AbstractProduction of potato (Solatium tuberosum L.) in rotation with an N2‐fixing legume requires better information on the N contribution from the legume and on management of N fertilizer following a legume. Objectives of this research were to: (i) quantify N accumulation by legumes grown as either green manure or hay; and (ii) evaluate the vine and tuber yield response of a subsequent potato crop to legume and fertilizer N. We established rotations at two Michigan locations in 1987 on McBride sandy loam (coarse‐loamy, mixed, frigid Alfic Fragiothods) and Oshtemo sandy loam (coarse‐loamy, mixed, mesic Typic Hapludalfs). First‐year crops included: alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), and red clover (Trifolium pratense L.) grown as both green manure (0 harvests) and hay (two or three seeding‐year harvests); non‐dormant ‘Nitro’ alfalfa hay; sweetclover (Melilotus spp.) and hairy vetch (Vicia villosa Roth) green manures; corn (Zea mays L.); fallow; and potato. The second‐year crop was potato, fertilized with 0, 75, 150, or 225 kg N ha−1. Plowdown N yield [PDN = fall(herbage + root)N + spring herbage N] of legumes ranged from 33 (fall‐seeded hairy vetch) to 238 kg N ha−1 (sweetclover), with the PDN yield of alfalfa, red clover, sweetclover, and spring‐seeded hairy vetch generally exceeding 150 kg ha−1. Seeding‐year harvest of legumes tended to have little effect on PDN yield, compared to a green manure crop of the same species. Potato vine dry matter and N content late in the season were 61 to 100 and 75 to 145% higher, respectively, following legumes than following non‐legumes, but total and marketable tuber yields were not affected by rotation at either location. Fertilizer N rate increased total, marketable, and cull tuber yield at MRF, with optimum N rates of about 120 and 170 kg ha−1 for marketable and total tuber yield, respectively. Nitrogen rate had no effect on tuber yield at KBS, suggesting that moisture, not available N, limited tuber yield. The difference in vegetative and tuber yield responses to rotation indicates that legume N eventually became available to the potato crop, but probably not early enough in the growing season to affect tuber initiation.
Rice Shoot Response to Root Confinement within a Membrane
Authors: Slaton N. A. , Beyrouty C. A. 
Published: July 2010

AbstractA porous membrane has been used for root studies of upland crops but not for crops grown under submerged conditions. A field study was conducted to compare the growth of paddy rice (Oryza sativa L.) with and without root confinement within a porous membrane. Three membrane configurations were compared: (i) a narrow membrane; (ii) a wide membrane; and (iii) a modified wide membrane. Root confinement within membranes reduced all shoot growth and yield parameters compared to soil‐grown plants (control). Reductions in shoot growth and yield parameters were usually least for the modified wide membrane and greatest for the narrow membrane.
Relationships between Corn Yields and Soil Nitrate in Late Spring
Authors: Binford G. D. , Blackmer A. M. , Cerrato M. E. 
Published: July 2010

AbstractRecent studies have shown good correlations between corn (Zea mays L.) yields and concentrations of NO3 in the surface 30‐cm layer of soil in late spring. Here we report additional correlations and evaluate the benefits of sampling to 60 cm instead of to 30 cm only. The study involved 45 site‐years (1346 plot‐years) of data collected in 1987, 1988, and 1989 in Iowa. Weather conditions were dryer than normal, with a severe drought occurring in 1988. Each site‐year included seven to 10 rates of N applied before planting. Samples representing the surface 0‐ to 30‐cm and the 30‐ to 60‐cm layers of soils were collected when corn plants were 15 to 30 cm tall. Nitrate concentrations in these soil layers were correlated with grain yields. The deeper sampling slightly improved the correlations between grain yields and soil NO3 concentrations, but the advantage was probably not great enough to justify the costs of the deeper sampling. The critical concentration of NO3 was 23 to 26 mg N kg−1 in the surface 30‐cm layer of soil and 16 to 19 mg N kg−1 in the surface 60‐cm layer of soil. Overall, the results support the idea that a soil test based on concentrations of NO3 in the surface 30‐cm layer of soil when corn plants are 15 to 30 cm tall has great promise for improving N management during corn production.
Physiological Traits Associated with Grazing‐Tolerant Alfalfa
Authors: Brummer E.C. , Bouton J.H. 
Published: July 2010

AbstractMany alfalfa (Medicago sativa L.) cultivars do not persist under long‐term, continuous grazing. This study was conducted to examine the variation of physiological traits that may contribute to grazing tolerance. Plants of the grazing‐tolerant cultivars Alfagraze and Travois and the grazing‐intolerant cultivar Florida 77 were grown from seed (Study 1) and from cuttings (Study 2) in the greenhouse. Populations from each cultivar that survived 2 yr of continuous grazing in the field were also tested in Study 2. Plants were clipped either frequently (weekly) or infrequently (every 4 wk) for 20 wk. Measurements of root total nonstructural carbohydrates (TNC), root weight, top and stubble herbage yield, and stubble leaf area were taken at Weeks 0, 2, 4, 10, 12, 18, and 20. No differences were noted between populations in Study 2. Under infrequent clipping TNC levels for all cultivars were higher at 4 than 2 wk after clipping. Florida 77 produced high TNC and root and top weights only under infrequent clipping but had low TNC and root weights under both clipping regimes, produced low top and stubble herbage dry matter, but maintained high stubble leaf areas under frequent clipping. Alfagraze produced and maintained high TNC and root weights under both clipping treatments, but produced high stubble dry matter and leaf area under frequent clipping. The genetic potential of a cultivar to store large amounts of carbohydrates may enhance its grazing tolerance, although stubble leaf area is probably important in allowing maintenance of total nonstructural carbohydrates under frequent defoliation.
Forage Potential of Kura Clover and Birdsfoot Trefoil when Grazed by Sheep
Authors: Sheaffer C.C. , Marten G.C. , Jordan R.M. , Ristau E.A. 
Published: July 2010

AbstractKura clover (Trifolium ambiguum M. Bieb.) is a rhizomatous perennial legume that has not been adequately evaluated in the USA under grazing. Our objective was to compare kura clover and birdsfoot trefoil (Lotus corniculatus L.) persistence and productivity when seeded in monoculture and in a binary mixture and grazed by lambs. A controlled, high herbage allowance (mean of 7.4% of lamb body weight in forage dry matter per day) was applied for 4 yr to pastures on a Waukegan silt loam (fine‐silty over sandy, mixed, mesic Typic Hapludoll). Initial seeded legume composition of monocultures was >95%, while the composition of the kura clover‐birdsfoot trefoil mixture was initially 10 and 90%, respectively. By the fourth year of grazing, the kura clover monoculture and mixture had >99% kura clover, while the birdsfoot trefoil monoculture had only 20% birdsfoot trefoil (80% broadleaf weeds). At the initiation of grazing, kura clover had 20% greater leafiness and higher forage quality than birdsfoot trefoil. Animal days per hectare and liveweight gain per hectare were initially similar for the legume monocultures and mixtures, but by the fourth year were 105% and 86% greater, respectively, for the kura clover dominated mixture and the kura clover monoculture than for the birdsfoot trefoil monoculture. Average daily lamb gain was similar (4‐yr mean of 199 g per lamb) for the treatments each year. Seeding with birdsfoot trefoil did not reduce the incidence of lamb bloat (6%) that occurred on kura clover pastures when kura clover comprised 20% or more of the mixture. Kura clover has potential as a pasture legume in the northern USA because of its excellent persistence, ability to spread, and high forage quality. Additional evaluation of animal performance under lower herbage allowance and on determination of kura clover compatibility with grasses in mixtures is warranted.
In Situ Ruminal Protein Degradation of Switchgrass and Smooth Bromegrass
Authors: Mullahey J.J. , Waller S.S. , Moore K.J. , Moser L.E. , Klopfenstein T.J. 
Published: July 2010

AbstractPerformance of livestock grazing warm‐season, perennial grasses is generally greater than would be expected given their relatively low protein concentrations. Two experiments were conducted to assess ruminal escape protein using an in situ rumen technique for switchgrass (Panicum virgatum L.) and smooth bromegrass (Bromus inermis Leyss.). Whole‐plant, leaf, and stem samples were harvested at specific stages of maturity in 1987. Duplicate samples of each grass were incubated for 12 h in situ. Escape protein values were expressed as concentration [grams escape protein per kilogram dry matter (DM) adjusted for acid detergent insoluble nitrogen (ADIN)] and as a percentage of total plant protein concentration (grams protein per kilogram DM adjusted for ADIN) to characterize protein composition. Whole‐plant escape protein concentration was greater (P < 0.05) in switchgrass (31.8 g kg−,1 DM) than smooth bromegrass (22.3 g kg−1 DM), averaged across all growth stages, and generally declined with maturity in both species. Escape protein concentration was consistently greater (P < 0.05) in leaves (50.8 g kg<1 DM) than in stems (19.3 g kg<1 DM) averaged over species and growth stages. As the proportion of stem to leaf increased during maturation, whole‐plant escape protein concentration decreased. Escape protein percentage was similar for smooth bromegrass leaves and stems while switchgrass stems were generally higher than leaves. Escape protein percentage of whole‐plant switchgrass (50.9%) was greater (P = 0.08) than smooth bromegrass (20.5%) over all harvest dates. Anatomical differences between switchgrass (C4) and smooth bromegrass (C3) may partially explain differences in ruminal protein degradation and subsequent animal performance.
No‐till Plot Planter with Row Space and Fertilizer Placement Capabilities
Authors: Kushnak G.D. , Thaut R.E. 
Published: July 2010

AbstractNo‐till research involving row space and subsurface fertilizer placement variables requires a planter that allows quick adjustment to provide a wide range of row space and fertilizer placement positions. A no‐till planter with adjustable row spacing was constructed to allow fertilizer placement below seed, with seed, and any distance between seed rows. Row space was quickly changed to any width, including paired‐row configurations, from 0.15 to 1.27 m. With two people it required 10 min to change row space, fertilizer placement, and rate. The planter was used to establish small grains, large‐ and small‐seeded legumes, and wheatgrass. Planting was successful through 2200 and 3018 kg ha−1 of prostrate and standing small‐grain residue, respectively. Higher residue levels were not tested. The planter was mounted on a 50‐hp tractor with a three‐point hitch.
Quantitative Physical Assessment of Organic Materials Used in Sports Turf Rootzone Mixes
Authors: McCoy Edward L. 
Published: July 2010

AbstractPeats and other organic materials are commonly used in sports turf rootzone mixes, yet few quantitative guidelines exist for selecting appropriate materials and incorporation rates. This study was conducted to assess the relative merits of organic sources and to identify a physical measure to assess the role of organic materials in rootzones. Five organic materials with organic contents ranging from 96 to 40% by weight and fiber contents ranging from 54 to 7% by weight were mixed with a mason sand at rates of 10, 20, and 30% by volume. Standard physical measures of bulk density, compressibility, saturated hydraulic conductivity, non‐capillary porosity, and plant‐available water revealed few differences between the organic sources for a given mixing rate. Regression relations between organic matter by weight and bulk density, and available water suggest that 3% organic matter (by weight) is required in order to attain bulk densities < 1.45 Mg m−3, and 3.5% organic matter is required for available water contents >0.2 m3 m−3. Water retention curves were used to determine the pore volume distribution for each organic source and mixing rate. The pore volume distributions were bimodal and revealed differences between the organic sources and mixing rates that were not apparent from standard physical tests. Analysis of these distributions suggest that organic sources having fiber contents >45% may be excessively coarse, and organic material incorporation rates should be selected so the final mix does not exceed 3.5% organic matter by weight.
Utilizing Genotype–by–Weather Interactions for Selecting Wheat Cultivars
Authors: Feyerherm A.M. , Sears R.G. , Paulsen G.M. 
Published: July 2010

AbstractCrop cultivars should be widely adapted to varying climatic regions for optimum performance, but genotype by weather interactions often limit adaptation to subregions. Our objective was to quantify genotype by weather interaction effects between pairs of cultivars and thereby identify subregions where new cultivars could be expected to outyield established ones with prescribed confidence. Genotype by weather interaction effects were quantified by regressing yield differences (D) between a new and an established cultivar on weather variables using cultivar performance trial data for winter wheat (Triticum aestivum L.). A predicted value (D̂) was assumed to estimate the mean, E(D), of a hypothetical population of performance trials for a specified location‐year. If the 95% confidence interval for E(D) covered only positive values, it is highly likely that E(D) was greater than zero and the new cultivar outyielded the established one in that location‐year. For a specific location, inferences were extended to years not included in model development using the regression equation and associated confidence intervals for E(D). Results indicated that a new cultivar Karl would have outyielded a popular cultivar Newton in more than 50% of the years from 1950 through 1989 at locations in Kansas with mean annual precipitation exceeding 711 mm. Further, the mean yield of Karl would have exceeded that of another popular cultivar Arkan in over 50% of the years over all of Kansas. The methodology for quantifying genotype by weather interactions and extending results to years not included in model development provides important information for recommending new cultivars for specific subregions.
Early‐Season Production Systems Utilizing Indeterminate Soybean
Authors: Savoy B. R. , Cothren J. T. , Shumway C. R. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] yield and yield components can be influenced by production practices that affect soil moisture and plant architecture. This study evaluated the effects of variations in soil moisture and inter‐row spacing on seed yield and yield components of an indeterminate soybean grown in an early‐season production environment in south‐central Texas. ‘Williams 82’ soybean (Maturity Group III) was planted in mid‐April in 1988 and 1989 near College Station, TX (30° 32′ 33″ N lat) in a Ships clay (very fine, mixed, thermic Udic Chromusterts) that is intergraded with Weswood silt loam (Fluventic Ustochrepts). Harvest occurred in late August. Soil moisture regimes were irrigation and no irrigation; inter‐row spacings were 0.36 and 1.02 m. Seed yields were greater in 1989 (4260 kg ha−1) than in 1988 (3550 kg ha−1). Soil moisture level and row‐spacing treatments had no effect on seed yield either year. Year‐by‐inter‐row spacing interactions were significant for single seed mass and total seed and pod number. Seed size was greater in 1989 than in 1988. The year‐by‐soil moisture level interaction was significant for mean seed per pod. Both years, yield component characteristics were more consistent in 1.02‐m rows than in 0.36‐m rows. These results indicate that adequate yields, with maturation in late‐August, are possible using an adaptable indeterminate soybean in an early‐season production environment in south‐central Texas.
Total Nonstructural Carbohydrates and Nitrogen of ‘Florigraze’ Rhizoma Peanut
Authors: Saldivar A.J. , Ocumpaugh W.R. , Gildersleeve R.R. , Prine G.M. 
Published: July 2010

Abstract‘Florigraze’ rhizoma peanut (Arachis glabrata Benth.) is a perennial, rhizomatous forage legume that is grown in Florida and the southern Gulf Coast. Little is known about total nonstructural carbohydrate (TNC) or N concentrations in plant parts of rhizoma peanut. Two field studies were conducted near Gainsville, FL on Arredondo loamy sands (loamy, siliceous, hyperthermic Grossarenic Paleudults) to determine (i) which plant component(s) serves as primary TNC and N storage organ(s), (ii) pattern of TNC and N accumulation in undisturbed plants, and (iii) effects of defoliation upon TNC and N. An establishment‐year study was conducted in 1980 and 1981 using spaced plants, and a defoliation‐frequency study (undefoliated vs. defoliated every 2, 6, or 8 wk) was conducted in 1981 on plants that were undisturbed in 1980. Entire plants (hills) were dug every 3 to 8 wk throughout the year and separated into shoots and primary and secondary rhizomes. Shoot TNC concentration showed no pattern of accumulation. Concentrations of TNC and N were similar in primary and secondary rhizomes. In new plantings, rhizome TNC declined in early‐season to 100 g kg−1, was low and variable (100–200 g kg−1) from May through September, and increased to 400 g kg−1 by November. Rhizome N declined from 30 g kg−1 in spring to 20 g kg−1 during the establishment year with a slight increase in autumn. All defoliation treatments reduced TNC and N concentrations of rhizomes compared to nondefoliated peanuts. Florigraze accumulates a high concentration of TNC (400–700 g kg−1) in its rhizomes in autumn. Our data suggest that defoliation should be avoided for establishing plants and plants that will be used as a source of rhizomes for propagation.
Growth Analysis of ‘Florigraze’ Rhizoma Peanut: Shoot and Rhizome Dry Matter Production
Authors: Saldivar A. J. , Ocumpaugh W. R. , Gildersleeve R. R. , Prine G. M. 
Published: July 2010

Abstract‘Florigraze’ rhizoma peanut (Arachis glabrata Benth.) is a perennial tropical forage legume grown in Florida and the southern Gulf Coast. It is vegetatively propagated with rhizomes and regrows from rhizomes in the spring following winter frost‐kill, but little is known about its growth and development. Two studies were conduced near Gainesville, FL, on Arredondo loamy sands (loamy, siliceous, hyperthermic Grossarenic Paleudults) in 1980 and 1981 to characterize aerial and underground growth of Florigraze. The establishment‐year study used spaced‐planted hills (three to five rhizomes per hill) in 1980 and 1981. The defoliation‐frequency study (undefoliated vs. defoliated every 2, 6, or 8 wk) was conducted in 1981 on plants (hills) that were undisturbed at the 1980 site. Entire hills were dug every 3 to 8 wk, and separated into shoots and primary and secondary rhizomes. In the establishment year, accumulated dry matter (DM) of shoots and rhizomes increased until September, when shoot growth plateaued or declined while rhizome growth continued. During cooler autumn months, photosynthate produced in shoots was partitioned into rhizome growth. Secondary rhizomes (smaller non‐branched rhizomes) constituted the bulk of rhizome mass. Shoot/rhizome ratios increased from zero at planting to about 1.5 to 2 by late summer, then declined to about 0.5 in autumn. Defoliation treatments decreased rhizome DM production by one‐half (8 wk) to two‐thirds (2 and 6 wk) that of the undefoliated control. Our results indicate that defoliation should be avoided for establishing plants and plants that will be used as a source of rhizomes for propagation.