bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spring Wheat Response to Enhanced Ammonium Supply: I. Dry Matter and Nitrogen Content
Authors: Camberato J. J. , Bock B. R. 
Published: July 2010

AbstractSpring wheat (Triticum aestivum L.) grain dry matter (DM) has been increased in previous greenhouse experiments through the use of a nitrification inhibitor (NI), which provides an enhanced ammonium supply (EAS). The objective of this research was to determine, under greenhouse conditions, the effect of EAS on the accumulation and partitioning of DM and N at several stages of plant development and on the yield components (heads plant−1, kernels head−1, and kernel weight). Enhanced NH4 supply increased plant DM at 18 d after plant emergence, boot stage, 7 d after anthesis, and maturity. Enhanced NH4 supply did not alter the relative partitioning of DM among leaf, stem, and grain at any stage of development. Effects of EAS on plant and grain DM at maturity increased with increasing N rate. At the highest N rates, grain DM was increased 18 and 6% in two experiments. Nitrogen and moisture stress appeared to alter grain DM response to EAS. Increased grain DM was associated with an increased number of heads plant−1. Kernels head−1 were decreased with EAS, but kernel weight was not affected. Consequently, EAS increased heads plant−1 more than grain DM. At growth stages prior to maturity, EAS increased plant N uptake. At maturity, plant N uptake was slightly and inconsistently affected by EAS; however, the proportion of plant N in the grain was increased by EAS. This indicated a greater translocation of N from the stem to the grain with EAS. In general, increased spring wheat grain DM is associated with proportional increases in plant DM throughout plant development, but not necessarily with proportional increases in plant N uptake. Heads plant−1 is the only yield component increased positively by EAS and thus warrants further research.
Legume Cover Crops as a Nitrogen Source for No‐Till Corn and Grain Sorghum
Authors: Blevins R. L. , Herbek J. H. , Frye W. W. 
Published: July 2010

AbstractIncreasing use of conservation tillage has brought about a renewed interest in growing winter legume cover crops. Field experiments were conducted to determine the fertilizer N equivalency of hairy vetch (Vicia villosa Roth), bigflower vetch (Vicia grandiflora W. Koch var. Kitailbeliana), and rye (Secale cereale L.) to no‐tillage corn (Zea mays L.) and grain sorghum [sorghum bicolor (L.) Moench]. A fallow treatment, consisting of stalk residue only, was used as a comparison. Fertilizer N rates for corn were 0, 50, or 100 kg N ha−1 for 1980 to 1983 and 0, 85, or 170 kg N ha−1 for 1984 to 1987. Hairy vetch produced the most cover crop dry matter with the highest percentage of N. During 1980 to 1983, corn grain yields were significantly higher with the vetch treatments than with rye or fallow treatments at the 0 and 50 kg N ha−1 rates with a tendency toward higher yields at the 100 kg N ha−1 rate. During 1984 to 1987, corn yields from the vetch treatments were significantly higher than the other cover treatments at all N levels. Grain sorghum, like corn yields, were greater with the vetch treatments than with the rye or fallow treatments, although the bigflower vetch treatment was not significantly higher than the fallow treatment at the 170 kg N ha−1 rate. The estimated fertilizer‐N equivalency of the hairy vetch‐N in the corn experiment was 75 kg N ha−1 and bigflower vetch was 65 kg N ha−1. Fertilizer N equivalency values in the grain sorghum experiment were estimated to be 125 kg N ha−1 for hairy vetch and 135 kg N ha−1 for bigflower vetch.
Water Relations of Differentially Irrigated Cotton Exposed to Ozone
Authors: Temple Patrick J. 
Published: July 2010

AbstractThis field study was conducted to test the hypothesis that plants chronically exposed to O3 may be more susceptible to drought kcause OM3 typically inhibits root growth and increases shoot‐root ratios in plants. Cotton (Gossypium hirsutum L. cv. Acala SJ‐2) was grown in open‐top chambers on Hanford coarse sandy loam (coarseloamy, mixed, non‐acid, thermic, Typic Xerorthents) in Riverside, CA. Plants were grown under three irrigation regimes: optimum water for lint production (OW), suboptimum or moderate drought stress (SO), and severely drought stressed (SS) and were exposed to seasonal 12 h (0800–2000) O3 concentrations of 0.015, 0.074, 0.094, or 0.111 μL L−1. Leaf xylem pressure potentials (Ψ1) and soil water content (Ψv) were measured weekly from June to October. Mean seasonal Ψ1 increased from −1.89 MPa to −1.72 MPa in low to high O3 treatments, averaged across soil water regimes. Ozone had no effect on seasonal water use of cotton, but water use efficiency was significantly reduced by O3 in OW and SO, but noit in SS treatments. Drought‐stressed plants extracted proportionally greater amounts of water from deeper in the soil profile than OW cotton, and O3 had no apparent effect on this redistribution of roots in the soil. Since O3 had no apparent effect on the ability of droughtstressed cotton to maintain Ψ1 and to increase root growth relative to shoot growth, this suggests that O3 may have little or no effect: on the potential of cotton to adapt to or tolerate drought.
Root Zone Water Balances of Three Low‐Input Millet Fields in Niger, West Africa
Authors: Payne W. A. , Wendt C. W. , Lascano R. J. 
Published: July 2010

AbstractIt is often assumed that pearl millet [Pennisetum americanum (L.) Schum.] production is limited by water supply despite the fact that little published data exist on water balances of low‐input millet fields. The objectives of this study were to: (i) quantify components of the field water balance of three sites, each in a different rainfall zone, and (ii) determine whether water supply was the primary limiting constraint to production at each site. The study was conducted on sandy soils in Niger, West Africa, during the 1985 growing season. Fields were near the villages of Chikal, N'Dounga and Kala Paté, which received 223, 344 and 428 mm of total rainfall, respectively. Soils were classified as Ustic Torripsamment at Chikal, Psammentic Paleustalf at N'Dounga, and Alfic Ustipsamment at Kala Paté Water balances were calculated to the depth of maximum root penetration, which was determined at harvest by digging pits. Measurements were made using a field calibrated neutron probe and nonrecording rain gauges. Results indicate that depth of maximum root penetration was not correlated with rainfall received after planting. Seasonal crop water supply was greatest at N'Dounga, where root development was greatest. Drainage below the zone of maximum root penetration was significant at Kala Paté at 43 d after sowing, when cumulative rainfall was only 143 mm, but negligible at the other sites. Drainage could not be separated from evapotranspiration at Kala Paté 67 d after sowing and thereafter. Total evapotranspiration was 272 mm at N'Dounga and 201 mm at Chikal. Cumulative change in water storage in the zone of maximum root penetration was 0 mm at Chikal, 39 mm at N'Dounga, and 46 mm at Kala Paté. Based on the amount of water held above − 1500 kPa in the zone of maximum root penetration and profile water distribution, we conclude that water was the primary limiting constraint only at Chikal in 1985. Water supply did not appear to be the primary limiting constraint at N'Dounga and Kala Paté. Similar conclusions were obtained using the amount of root zone water held above − 100 kPa. The study suggests that water supply may not be assumed a priori to be the primary production constraint to low input millet fields such as those studied here.
Harvest Management of a Crimson Clover Cover Crop For No‐Tillage Corn Production
Authors: Holderbaum J. F. , Decker A. M. , Meisinger J. J. , Mulford F. R. , Vough L. R. 
Published: July 2010

AbstractLegume cover crops are valuable N sources for no‐tillage corn (Zea mays L.). However, little research has been done in assessing the management options for legume cover crops. Field studies were conducted on a Coastal Plain Matapeake silt loam soil (fine‐silt, mixed, mesic Typic Hapludult) from 1983 through 1986 to determine the effects of various harvest management schedules on total N contribution of legume cover crops, subsequent corn grain and silage yields, and total forage (combined cover crop and corn herbage) production. A crimson clover (Trifolium incarnatum L.) cover crop was subjected to no harvest; spring silage harvest with clippings removed (spring silage); and simulated pasture harvests with clippings from multiple harvests removed (pasture removed) or returned (pasture returned). A no‐cover control treatment was also included. No‐tillage corn was grown in the cover crop residues and two fertilizer N (FN) rates (0 and 90 kg ha−1) were applied in a split‐block design to each harvest management treatment. Averaged over 3 yr, multiple harvests of the cover crop vs. a spring silage harvest resulted in lower cover crop herbage yields (3.0 vs. 4.7 Mg ha−1) and total N content (114 vs. 146 kg N ha−1) for the multiple harvests. Corn grain and silage yields and corn N uptake were consistently higher following crimson clover cover than for no cover, regardless of harvest management, and were generally higher when the cover was left in place than following removal of the cover. There were FN responses regardless of harvest management treatment. The reduction in corn silage yield when the cover crop was harvested and removed was less than the cover crop herbage dry matter yield, resulting in greater total forage production when the cover crop was harvested as forage. Results suggest that harvest management options of a crimson clover cover crop offer flexibility in either optimizing subsequent corn grain yields or total forage production for no‐tillage cropping systems and provide control over how cover crop N is utilized in the overall cropping system.
Growth Patterns of Perennial Grasses in the Annual Grassland Type of Southwest Oregon
Authors: Borman M. M. , Krueger W. C. , Johnson D. E. 
Published: July 2010

AbstractSouthwest Oregon and northern California foothills are currently dominated by a variety of annual plant species. This study was designed to assess the potential of established perennial grasses to occupy two sites in the foothills ecosystem, Mediterranean/Maritime climatic regime, of southwest Oregon. Soils at Sites 1 and 2 are Darrow silty clay loam (fine, montmorillonitic, mesic Vertic Argixerolls) and Carney clay (fine, montmorillonitic, mesic Typic Chromoxererts), respectively, and annual precipitation at the sites averages 500 mm. Growth patterns of the perennial grasses were contrasted among each other and to the resident annual plants during fall, winter and spring growth periods. Of the perennial grasses, Idaho fescue (Festuca idahoensis Elmer), native to the area, and ‘Berber’ orchardgrass (Dactylis glomerata L.), introduced, most closely emulated the growth patterns of the resident annual grasses. These grasses initiated growth sooner, continued some growth through the winter and matured earlier than the other perennial grasses tested. Once established, Idaho fescue and Berber orchardgrass should be able to effectively compete with the resident annuals for resources and maintain their populations.
Continuous Application of No‐Tillage to Ohio Soils
Authors: Dick* W. A. , McCoy E. L. , Edwards W. M. , Lal R 
Published: July 2010

AbstractNo‐tillage (NT) crop production practices have been continuously maintained at four sites in Ohio for more than 25 yr. The original experiments involving NT were designed to determine how much tillage was required to produce crops with satisfactory yields and how tillage and rotation interact to effect crop yields, especially corn (Zen mays L.). Long‐term effects of NT on crop yields and soil properties are generally not known because few sites exist with histories of ≥20 yr of NT. This paper reports yield trends of corn and soybean [Glycine max (L.) Merr.] and changes in soil properties that occurred when NT was continuously practiced on soils in Ohio. Significantly lower yields for NT, as compared to conventional tillage (CT), were observed for monoculture corn and for soybean in rotation during the first 18 yr on a very poorly drained Mollic Ochraqualf soil. The yield differences observed for corn could be largely eliminated by crop rotation and for soybean by the use of phytophthera resistant/tolerant soybean cultivars. On a well‐drained Typic Fragiudalf soil, crop yields were always higher with NT than with CT. After 18 yr, yield trends indicated the negative impact of NT on the very poorly drained soil was greatly decreased and the yield advantages associated with NT on the well‐drained soil became even more pronounced. The change in yield trends did not appear to be associated with change in weather patterns. The long‐term NT sites also revealed organic matter, nutrients, and soil enzymes accumulated at the soil surface but decreased deeper (>20 cm) in the soil profile. Surface water runoff was found to be greatly decreased from the long‐term NT watershed site (≈9% slope) with only 12 mm of runoff measured between 1979 and 1985.
Botanical Composition of Tropical Grass‐Legume Pastures Estimated with Near‐Infrared Reflectance Spectroscopy
Authors: Pitman W.D. , Piacitelli C.K. , Aiken G.E. , Barton F.E. 
Published: July 2010

AbstractQuantifying pasture composition requires either laborious or subjective approaches. Evaluations of near‐infrared reflectance spectroscopy (NIRS) to determine botanical composition of mixed pasture swards have shown potential. In this study, characterization of botanical composition of pastures comprised primarily of bahiagrass (Paspalum notatum Flugge), aeschynomene (Aeschynomene americana L.) and phasey bean [Macroptilium lathyriodes (L.) Urb.] by NIRS was evaluated. Three approaches (hand‐composited samples, single‐component samples, and actual pasture samples) were compared for equation development. Theoretical potential of NIRS is illustrated by high coefficients of determination (0.98–0.99) and low standard errors (1.4–2.9%) of equations for the above species from hand‐composited samples. Equations developed from the three approaches were evaluated for estimation of the botanical composition of a separate group of pasture samples. Equations developed from hand‐composited samples from a single source of each component were not acceptable for estimating composition of pasture samples despite the excellent calibration statistics. Single‐component samples approached adequate results only for composite total grass and total legume groups, even though the pasture sample composition appeared to be well represented in the calibration sample set. Equations from pasture samples provided useful estimates of sample means, although some individual samples were poorly estimated. Thus, botanical composition of these pastures may be estimated using equations from actual pasture samples, and estimates of total grass and total legume may be obtained from use of single‐component samples, which provides further labor reductions. A comparison of original software and updated software packages CAL, BEST, REG70, and partial least squares principal component regression showed none to be consistently superior.
Plant Responses to Stocking Rate in a Subtropical Grass‐Legume Pasture
Authors: Aiken G.E. , Pitman W.D. , Chambliss C.G. , Portier K.M. 
Published: July 2010

Abstract‘Florida’ carpon desmodium [Desmodium heterocarpon (L.) DC] is a persistent legume under grazing but is often difficult to establish. Aeschynomene (Aeschynomene americana L.) and, especially, phasey bean [Macroptilium lathyroides (L.) Urb.] establish more reliably. Overseeding a mixture of these legumes in bahiagrass (Paspalum notatum Flugge) pastures could provide the quality forage and N input of legumes initially from the rapidly establishing species and for extended periods from the persistent carpon desmodium. The objective of this study was to evaluate the potential of such mixtures. Effects of stocking rate and grazing season on botanical composition, herbage availability, and herbage nutritive value were evaluated on a Pomona fine sand (sandy, siliceous, hyperthermic Ultic Haplaquod). Following overseeding of legumes in March 1987, pastures were grazed at three stocking rates in summer 1987 and in spring and summer 1988. Carpon desmodium increased from less than 1% at the start of grazing in 1987 to over 7% of the live herbage in 1988. Combined percentage of aeschynomene plus phasey bean decreased during 1987 from more than 4 to 1.6%. Carpon desmodium percentage was highest (P < 0.10) at the intermediate stocking rate, while percentage of other legumes was not affected by stocking rate. Herbage mass decreased linearly with increases in stocking rate in both summer grazing seasons. Leaf/stem ratio and nutritive value of legume leaf and stem were not affected by stocking rate but decreased with time during each grazing season. The short‐lived legumes, aeschynomene and phasey bean, provided high quality forage during the establishment period of carpon desmodium but contributed negligibly during the second year.
Corn Responses to Post‐tasseling Nitrogen Deprivation and to Various Ammonium/Nitrate Ratios
Authors: Reddy K.S. , Mills H.A. , Jones J.B. 
Published: July 2010

AbstractCorn (Zea mays L.) takes up more than half of its total N after tasseling. An experiment was conducted to determine how the availability of N and the N form, NH4 or NO3, during the post‐tasseling period affect corn plant growth, ear development, and nutrient composition. In this experiment, corn hybrid ‘Pioneer 3343’ plants were grown hydroponically in pots outdoors with 50:50 NH4:NO3 up to the emergence of tassels and then the plants were either deprived of N or changed to various ratios of NH4:NO3 nutrition and grown to maturity. Nitrogen deprivation reduced both vegetative (stalk and leaf) and reproductive (cob, total kernel, and individual kernel) dry matter accumulation. Continuous supply of 50:50 ratio of NH4:NO3 produced greater vegetative dry matter than changing to either higher or lower ratios of NH4:NO3. The ratio of NH4:NO3 did not affect the ear dry matter production. Nitrogen deprivation decreased both leaf and kernel N concentration. While 50:50 NH4:NO3 ratio increased the leaf N concentration, all NH4 increased the kernel N concentration compared to other ratios. Nitrogen deprivation also reduced the concentrations of Mg, Fe, Mn, Zn, and B in the leaves but had no effect on the kernel nutrient composition. The cation and anion concentrations in the leaves and kernels were not according to the NH4 and NO3 effects (viz., uptake of cations greater and anions lower with NH4 than with NO3 nutrition), which were previously observed before tasseling. This difference may be due to a change in the uptake capacity for these nutrients after tasseling.
Transplantation as a Soybean Field Technique to Modify Root Nodule Occupancy
Authors: Fuhrmann Jeffry J. , Vasilas Bruce L. 
Published: July 2010

AbstractField studies of symbiotic interactions between soybean (Glycine max [L.] Merr.) and Bradyrhizobium japonicum (Kirch.) Jordon are often limited by an inability of specific inocula to compete successfully with indigenous bradyrhizobia for root nodule sites. The objective of this note is to describe and evaluate a transplantation technique for modifying soybean root nodule occupancy under field conditions. Pre‐nodulated seedlings were prepared under greenhouse conditions in containers designed for the generation of transplants. The inoculation procedures used ensured that all nodules initiated prior to transplanting contained only selected strains of B. japonicum. The seedlings were transplanted to field microplots when approximately 3 wk old and subsequently allowed to develop normally. The transplanted seedlings exhibited high rates of survival and excellent yield potentials. Control of nodule occupancy on tap roots and adjoining portions of major lateral roots was nearly complete for several weeks after transplanting.
Mainstem Leaf Development and Tiller Formation in Wheat Cultivars
Authors: Krenzer E. G. , Nipp T. L. 
Published: July 2010

AbstractMainstem leaf stage and percent tiller formation are measurements utilized to evaluate the development of wheat (Triticum aestivum L.). This study was conducted to determine whether there are differences for these measurements among 11 winter wheat cultivars. Ten hard red winter wheat and one soft white winter wheat cultivars were grown in a controlled environment chamber to determine their rate of mainstem leaf stage and tiller formation percentage for coleoptile (TO), first (Tl), second (T2), and third tillers (T3) when plants are grown in the absence of stress. Growth conditions were 12‐h photophase at 24 °C and 12‐h dark at 15 °C. Light intensity averages 500 μmol m−2s−1 photosynthetic photon flux density. Cultivars ranged from 5.3 to 6.4 in mainstem leaf stage at 700 growing degree‐days (GDD) after seeding and in number of GDD required per leaf. Therefore, before attempting to model wheat development, the response of mainstem leaf appearance to GDD for specific cultivars must be determined. For percent tiller formation, TO was quite variable, and cultivar differences were not significant. Therefore, percent tiller formation of TO may be too variable for detection of treatment differences. Even though a significant percent tiller formation difference occurred among cultivars for Tl, all but one cultivar formed 90 to 100% of Tl, T2, and T3.
Effect of Rill Erosion during Early Vegetative Growth on Winter Wheat Yield
Authors: Rasmussen P.E. , Douglas C.L. 
Published: July 2010

AbstractThe long‐term effect of soil erosion on lowering soil productivity is well documented, but little is known about how rill erosion occurring during the crop growing season affects yield. Rill erosion effects on winter wheat (Triticum aestivum L.) growth and yield were determined in six fields where rill erosion occurred during early vegetative growth. Soils were Walla Walla (coarse silty, mixed mesic Haploxeroll) or Athena (fine silty, mixed mesic Haploxeroll) silt loams at least 2 m deep. Rills were followed across landscape positions on slopes ranging from 1 to 15%. Rills paralleled rows in all six studies, and traversed rows in two of the six. Rill erosion reduced head density, dry matter yield, N uptake, and grain yield at all sites. The rill/non‐rill (R/NR) grain yield ratio (per square meter) varied from 0.84 to 0.94. The R/NR yield ratio was not affected by slope steepness or aspect, but was weakly correlated with yield level (greater loss at higher yields) and landscape position (lower slope positions had larger rills and greater yield loss). The grain R/NR ratio decreased with increasing rill depth but was not affected by rill width. Soil loss measured with a rillmeter was correlated with rill depth. The estimated yield reduction per ha associated with average rill development (11.7 cm deep rills, 26.7 kg m−2 soil loss in rill area, and 10 rill transects ha−1) was between 0.9 and 1.2%. Assuming a 36 Mg ha−1 soil loss (the average for sloping Haploxeroll soils of the Pacific Northwest), the calculated yield reduction from winter wheat fields yielding 5.2 Mg ha−1 is 88 kg grain ha−1 (about $13 ha−1 for wheat valued at $0.147 kg−1). This erosion cost would encompass a significant percentage of the landscape with sloping topography and is additional to any costs associated with long‐term loss of soil productivity.