bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparison of Two Nitrogen Credit Methods: Traditional vs. Difference
Authors: Lory John A. , Russelle Michael P. , Peterson Todd A. 
Published: July 2010

AbstractCereals and other nonlegumes typically require less fertilizer N when grown following a legume. Nitrogen credits for a previous legume crop often are used to reduce fertilizer N recommendations in combination with other site‐specific information. Researchers continue to use two methods of determining N credits, the traditional and difference techniques, which often produce unequal estimates. Our objective was to clarify when each method provides accurate N credit estimates. The traditional method compares yield of a nonfertilized nonlegume crop grown in rotation to the fertilizer N response curve of the continuously cropped nonlegume. This approach assumes that fertilizer N compensates for all benefits of rotation. The difference method compares the economic N rate of the nonlegume crop grown in rotation with that of the continuously cropped nonlegume. We use examples from the literature to demonstrate that when non‐N rotation effects are present, N credit estimates from the two methods will differ. The difference method is more accurate and should be used unless it has been demonstrated that non‐N rotation effects are not present.
Water Stress and Clipping Management Effects on Guineagrass: I. Growth and Biomass Allocation
Authors: Páez Alejandra , González O. María E. , Yrausquín Xiomara , Salazar Arturo , Casanova Angel 
Published: July 2010

AbstractGrowth and biomass allocation of grasses depend greatly on their management and water status. This study was conducted to determine the short‐term interacting effects of clipping height and frequency with water stress on growth and biomass allocation of guineagrass (Panicum maximum Jacq.). After seedling establishment, plants were clipped at four frequencies and three heights, followed by exposure to water stress. Some plants were reirrigated to determine recovery. Plants were harvested after the water stress and reirrigation periods. In response to water stress, plants clipped at greater heights experienced a greater reduction of leaf and culm biomass than plants clipped at lower heights. Root biomass of stressed plants increased linearly with increasing clipping height. Leaf area declined linearly in stressed plants and increased in unstressed plants as clipping height increased and frequency decreased. Leaf area ratio (LAR) and specific leaf weight (SLW) of unstressed plants varied little; for stressed plants, however, LAR decreased and SLW increased as clipping height increased and frequency decreased. In well‐watered plants, the root‐to‐shoot ratio (R/S) was lowest with higher clipping; in the stressed plants, R/S increased with increasing clipping heights. During rewatering, a height ✕ stress interaction for leaf and culm biomass and leaf area was due to a smaller recovery for higher‐clipped than for lower‐clipped plants. Water stress decreased leaf and culm biomass and leaf area, reducing LAR and increasing SLW. These effects were greater in plants cut to greater heights and less frequently. Water stress also enhanced root biomass, suggesting photosynthate migration toward the roots.
Influence of Core Aerification, Topdressing, and Nitrogen on Mat, Roots, and Quality of ‘Meyer’ Zoysiagrass
Authors: Dunn John H. , Minner David D. , Fresenburg Brad F. , Bughrara S.S. , Hohnstrater Chris H. 
Published: July 2010

AbstractThatch accumulation is a common occurrence in lawn and sports turf and is usually detrimental. We initiated aerification, topdressing, and N treatments in July 1987, to investigate their influence on thatch, mat, quality, and color of zoysiagrass (Zoysia japonica Steud. cv. Meyer). Turfgrass color responses to N were positive and strongly linear. Turfgrass quality was generally good to excellent in response to N. However, trends were not as well defined as color responses and varied according to month and year. The aerification + topdressing combination according to N level was nonsignificant for turfgrass quality in all months and significant for color only in October. Weight of mat, which consisted mostly of rhizomes, and root weights declined linearly in response to increasing N. The root weight response is consistent with research reports of C3 turfgrasses but inconsistent with earlier studies of C4 turfgrasses where root weights increased with increasing N. Mat depth averaged over N was equal in response to topdressing vs. no topdressing. Root weights and mat weight were significantly greater with topdressing. Mat organic matter (OM) was greater with no topdressing. Our results suggest that maintenance of zoysiagrass with only enough N to provide acceptable turfgrass density and color will give the best root development in nonsandy soils. Annual topdressing with soil similar to that of the growing site may further enhance root development.
Cotton Flowering and Boll Retention in Different Planting Configurations and Leaf Shapes
Authors: Heitholt James J. 
Published: July 2010

AbstractNarrow rows have the potential to increase boll numbers and lint yield of cotton (Gossypium hirsutum L.) compared with conventional row spacing. To optimize production in this system, it is important to know whether narrow‐row‐induced boll number increases are a result of increased seasonal flowering or increased boll retention. The objective of this study was to determine flower production (no. m−2), boll retention [(bolls/flowers) ✕ 1001, main stem node number, and yield as affected by row spacing and plant density. Field experiments were conducted in 1991 and 1992 on a Bosket fine sandy loam in narrow (51 or 76 cm) and wide rows (102 cm) using the normal‐ and okra‐leaf isolines of DES 24‐8 ne cotton. Plant densities were 5, 10, 15, and 20 plants m−2 in 1991 and 2, 3, 5, 10, and 15 plants m−2 in 1992. Averaged across leaf types and plant densities, 51‐cm rows increased the number of flowers by 12% and yield by 4% compared with 102‐cm rows in 1991. Boll retention was 40% for both row spacings. In 1992, averaged across leaf types and plant densities, 76‐cm rows increased the number of flowers by 21% and yield by 6% compared with 102‐cm rows. Boll retention was actually higher in 102‐cm rows (42%) than 76‐cm rows (36%). In general, plant density and the number of main stem nodes had little effect on flower numbers or boll retention. High plant densities tended to reduce the number of main stem nodes per plant. Averaged across row spacings, plant densities, and years, boll retention for normal‐leaf was higher than for okra‐leaf (50 vs. 29%). Results indicate that increased flower production rather than increased boll retention was responsible for the small narrow‐row yield increase.
Pod Yield and Stem Rot Evaluation of Peanut Cultivars Treated with Tebuconazole
Authors: Branch William D. , Brenneman Timothy B. 
Published: July 2010

AbstractTebuconazole {α‐[2‐(4‐chlorophenyl)ethyl]‐α‐(1,1‐dimethylethyl)‐1H‐1,2,4‐triazole‐1‐ethanol} has been registered by the U.S. Environmental Protection Agency for use in peanut (Arachis hypogaea L.) production as a new sterol‐inhibiting fungicide, under the trade name Folicur 3.6F. It is labeled to be used as four consecutive sprays between two applications of non‐sterol‐inhibiting fungicides for control of Phaeoisariopsis personata (Berk. & M.A. Curtis) Arx [syn. Cercosporidium personatum (Berk. & M.A. Curtis) Deighton], Sclerotium rolfsii Sacc., and Rhizoctonia solani Kühn. The combination of such new fungicides with improved peanut cultivars could be very beneficial for integrated pest management (IPM) practices. In 1992 to 1994, yield tests were conducted at the University of Georgia Coastal Plain Experiment Station following recommended applications of tebuconazole to determine which 10 runner‐type and 6 virginia‐type peanut cultivars had the highest pod yield and the lowest incidence of southern stem rot or white mold caused by S. rolfsii when grown with and without irrigation. Stem rot incidence was approximately twice as high in the irrigated as in the nonirrigated tests, and the highest incidence of stem rot was observed in the year with the greatest frequency of irrigation. The Georgia Browne and Georgia Green cultivars had the greatest yields and lowest stem rot incidence among the runner types, and Georgia Green had the greatest dollar value of all cultivars under both irrigated and nonirrigated conditions. Among the virginia types, NC 10C consistently had the highest incidence of stem rot over all 3 yr, and NC 7, VA‐C 92R, and NC‐V 11 had the greatest yields. These results show that certain runner and virginia‐type peanut cultivars perform significantly better than others using the current recommended application of tebuconazole.
Sugar Beet Production as Influenced by Row Orientation
Authors: Anda Angéla , Stephens William 
Published: July 2010

AbstractIn some crops, row orientation has been shown to influence yield through the effects on soil temperature. There has been no similar work on sugar beet (Beta vulgaris L.); thus, an experiment was conducted from 1992 to 1994 to determine the effects of row orientation on the growth and production of sugar beet in Hungary. Sugar beet was grown in large field plots oriented either north‐south (N‐S) or east‐west (E‐W) on a silty clay loam soil. Leaf area development, soil and canopy temperatures, and stomatal resistance were monitored during the growing season from April to October, and root yield, sucrose concentration, and sugar yield were recorded at harvest. All three seasons were warmer and drier than normal, so large soil water deficits developed during July to October each year. Significant differences in growth were observed, with rows oriented E‐W developing 15 to 21% larger leaf area indices. The E‐W rows also had greater canopy and interrow soil temperatures and lower stomatal resistances than N‐S rows, except during the middle of the day. On days with northerly winds >2 ms−1,, air and soil surface temperatures in E‐W oriented rows were greater than in N‐S rows throughout the day. Root and sugar yields were consistently greater in N‐S rows despite having a lower sucrose concentration than beet in the E‐W oriented rows. In 1994, sugar yields were 70% less than in 1993 as a result of Cercospora beticola infestation. In all years, the reduced yield in the E‐W rows was caused by more severe water stress compared to the N‐S rows. The higher temperatures also may have led to reduced partitioning of assimilate to roots with a consequent loss of harvestable yield. The results show that, in dry years, farmers may obtain up to 9% increases in sugar yield by planting sugar beet in N‐S rows. However, these conclusions need confirmation under wetter conditions.
Nitrogen in Sugarbeet Tops and the Growth of a Subsequent Wheat Crop
Authors: Moraghan John T. , Smith Larry J. 
Published: July 2010

AbstractNitrogen in sugarbeet (Beta vulgaris L.) tops can influence the yield of subsequent small‐grain crops. The objective of this field study was to determine the influence ofsugarbeet tops differing in N concentration on available soil N and plant growth. Responses of spring wheat (Triticum aestivum L.) to fall‐applied urea and high‐N (34.8 g N kg−1 in 1992 and 25.8 g N kg−1 in 1993) and low‐N (14.8 g N kg−1 in 1992 and 12.6 g N kg−1 in 1993) sugarbeet tops were compared on two Calciaquolls in Minnesota during 1993 and 1994. Application of 135 kg N ha−1, the optimal fertilizer rate in both years, increased wheat grain yields by 1832 kg ha−1 in 1993 and by 1518 kg ha−1 in 1994. High‐N sugarbeet tops, which contained 271 and 208 kg N ha−1 in the 1993 and 1994 experiments, respectively, increased grain yields by 2108 kg ha−1 in 1993 and by 1579 kg ha−1 in 1994. The corresponding responses with low‐N sugarbeet tops, which contained 64 kg N ha−1 in 1993 and 85 kg N ha−1 in 1994, were 424 and 392 kg ha−1. These latter responses were equivalent to only 42 and 51%, respectively, of the 1993 and 1994 increases obtained with 45 kg urea N ha−1. Separate field experiments in fallow microplots indicated that fall‐applied, high‐N sugarbeet tops mineralized appreciable quantities of NO3‐N by the following spring. Most of this mineralized NO3 was located in the upper 30 cm of soil. In contrast, considerable Cl added in sugarbeet tops was located in both the 0‐ to 30‐cm and 30‐ to 60‐cm soil depths. Sugarbeet tops can reduce the N‐fertilizer requirement of subsequent crops, and must be considered in relation to possible NO3 pollution of groundwater.
Intercropping Annual Medic with Conventional Height and Semidwarf Barley Grown for Grain
Authors: Moynihan Jones M. , Simmons Steve R. , Sheaffer Craig C. 
Published: July 2010

AbstractInterseeding annual legumes with grain crops has been proposed as a cropping strategy to enhance ground cover, thereby reducing weed competition, suppressing soil erosion, and providing N for use by subsequent crops. The potential of annual medics (Medicago spp.) for intercropping in small‐grain cropping systems has not been adequately assessed for the north‐central United States. Our objective was to evaluate a spring barley (Hordeum vulgare L.)‐annual medic intercrop system for barley grain yield, fall biomass production, suppression of fall weeds, and quantity of N available for incorporation into the soil. Field experiments were conducted in four Minnesota environments (Becker, Morris, Rosemount, and St. Paul). Conventional height ‘Robust’ and semidwarf ‘Royal’ barley were intercropped with each of three medic species [‘George’ black medic (M. lupulina L.), ‘Mogul’ barrel medic (M. truncatula Gaertn.) and ‘Santiago’ burr medic (M. polymorpha L.)]. Intercropping with medics reduced barley yields by an average of 6% at Rosemount, 30% at St. Paul, and 76% at Becker, compared with monoculture barley fertilized with N. Medics increased yields by 9% at Morris. Intercropping with medic reduced fall weed mass by an average of 65% across environments, compared with the fertilized Royal monoculture. Nitrogen available for incorporation from the barley‐medic intercrops ranged from 66 to 140 kg ha−1 over the environments, whereas N available for incorporation from fertilized barley monoculture ranged from 22 to 80 kg ha−1. We conclude that the prospects for successfully intercropping with annual medic in a barley grain production system are mixed and depend in part on the medic species used and barley stature. A wider array of medic types should be evaluated for their suitability in intercropping with small grains.
Developing Guidelines for Replanting Grain Sorghum: II. Improved Methods of Simulating Caryopsis Weight and Tiller Number
Authors: Heiniger Ronnie W. , Vanderlip Richard L. , Welch Stephen M. , Muchow Russell C. 
Published: July 2010

AbstractEnhancing the yield prediction accuracy of SORKAM, a growth model for sorghum [Sorghum bicolor(L.) Moench], requires improving the simulation of grain growth and the relationship between tiller number and minimum temperature. A new grain growth equation, developed from 1990 data collected at Manhattan, KS, relates grain‐filling rate to the rate of change of plant dry matter per caryopsis during the effective filling period. Additional functions are specified for the lag and leveling‐off phases of caryopsis growth, resulting in a new submodel, which was tested against data from Kansas and two Australian sites. The tiller number calculation was revised using three years of Manhattan data. After incorporating the new submodels, SORKAM outputs were compared with observed yields and yield components in three Kansas regions. The R2 values for yield increased from 0.27, 0.46, and 0.79 to 0.76, 0.69, and 0.90 for eastern, central, and western Kansas, respectively. Caryopsis weight comparisons showed that the revised model accounted for 48 to 72% of observed variability, up from 15 to 57% for the original model. Tiller number predictions also improved, although modestly.
Aboveground Carbohydrate and Nitrogen Partitioning in Common Vetch during Seed Filling
Authors: Caballero R. , Rebolé A. , Barro C. , Alzueta C. , Ortiz L. T. 
Published: July 2010

AbstractDuring seed filling in annual legumes, changes in concentration of assimilates occur simultaneously with plant partitioning, leading to net changes in yield of assimilates derived from the processes of accumulation and redistribution. Field studies were conducted during two growing seasons (1991–1992 and 1992–1993) in central Spain with the objectives of determining models of change for assimilate concentrations with advancing maturity and assessing efficiency of assimilate harvest relative to seed maturation. Concentration of total N, starch, total soluble sugars (TSS), neutral‐detergent fiber (NDF), acid‐detergent fiber (ADF), and acid‐detergent lignin (ADL) were determined in plant parts (seed, pod‐shell, leaf, and stem) of common vetch (Vicia sativa L.) at seven maturity stages defined as progressively higher dry matter (DM) content in the seed (200–250, 250–300, 350–450, 450–550, 600–700, 700–800, and >800 g DM kg−1 seed). Concentration of assimilates in plant parts changed over the whole seed‐filling period. During the phase of rapid seed growth (from 200–250 to 450–550 g DM kg−1 seed), assimilation was dominant for starch (net gain of 1086 kg ha−1), redistribution for TSS (net loss of 104 kg ha−1), and both process were operative in total N (net gain of 193 kg ha−1). During the ripening phase (from 450–550 to >800 g DM kg−1 seed), most chemical components except ADL showed a net loss. Maximum total accumulation for most mobile fractions except TSS was reached at the 450 to 550 g DM kg−1 seed maturity stage. Harvesting common vetch at this stage would represent maximum efficiency for total N and starch. Concentrations of nonstructural chemical components had a nonlinear trend while concentration of fiber fractions and lignin in vegetative structures showed a linear increasing trend over the seed filling phase of common vetch.
Reducing DCPA Losses in Furrow Irrigation by Herbicide Banding and Straw Mulching
Authors: Shock Clinton C. , Seddigh Majid , Hobson Joe H. , Tinsley Ian J. , Shock Byron M. , Durand Lucia R. 
Published: July 2010

AbstractThere are concerns about residues of DCPA (dimethyl 2,3,5,6‐tetrachloro‐1,4‐benzenedicarboxylate) and its two acid metabolites in surface runoff from furrow‐irrigated croplands. We studied the effects of mulching irrigation furrows with wheat (Triticum aestivum L.) straw on DCPA movement in runoff solution, with sediment, and in the soil profile. The study site had a Nyssa silt loam (coarse‐silty, mixed, mesic Xerollic Haplodurid) with a 3% slope. The field was planted to onion (Allium cepa L.) and was furrow‐irrigated 17 times. Prior to mulching, DCPA was either broadcast at 10 kg a.i. ha−1 or banded at 3.4 kg a.i. ha−1 on the top of beds between furrows. DCPA (parent plus metabolites) was measured in the runoff sediment of the first 6 irrigations, and in the runoff solution of the 1st, 3rd, and the 5th irrigation. Regardless of herbicide application method, mulching reduced DCPA losses in sediment of all irrigations and in the runoff solution of the fifth irrigation. Averaged across the 6 irrigations and the 2 herbicide application methods, mulching reduced DCPA transfer in sediment by about 90%. Straw mulch effects on DCPA losses were primarily through reductions in soil loss and runoff volume, whereas DCPA concentration was not affected in runoff solution and was increased in runoff sediment of some irrigations. Mulching increased infiltration of broadcast DCPA but tended to decrease infiltration of banded DCPA. Also, compared with broadcast DCPA, banding the herbicide reduced DCPA losses in sediment of some irrigations. We concluded that the combination of straw mulching and banding DCPA reduces herbicide transfer in surface runoff and movement into thesoil profile.
Effects of Surface‐Applied Limestone on the Efficiency of Urea‐Containing Nitrogen Sources for No‐Till Corn
Authors: Howard Donald D. , Essington Michael E. 
Published: July 2010

AbstractFertilizer N and lime amendments are commonly surface‐applied to no‐till (NT) production systems, but research on these practices under NT is limited. We examined the effect of surface‐applied limestone on the efficiency of urea, urea‐NH4NO3 (UAN), and NH4NO3 applied broadcast or injected for NT corn (Zea mays L.) production on loessal soils. No‐till field studies were established on two loessal soils in western Tennessee: a Memphis silt loam (fine‐silty, mixed, active, thermic Typic Hapludalf) that had been in NT for 7 yr and a Collins silt (coarse‐silty, mixed, acid, thermic Aquic Udifluvent) that had been under conventional tillage. Corn, with a wheat (Triticum aestivum L.) cover, was established on the Memphis soil in 1990. In 1994, corn was established on the Collins soil. The experimental design was a randomized complete block with a split‐plot arrangement of treatments. Agricultural limestone was surface‐applied at rates of 0 and 1.12 Mg ha−1, 1 to 3 wk before N treatment. The N treatments were UAN broadcast (UAN‐B), UAN injected (UAN‐I), urea broadcast or split‐applied (Urea‐B and Urea‐S), and NH4NO3 broadcast (AN‐B). Nitrogen treatments were applied at 168 kg ha−1 within 5 d after planting. For the split urea treatment, 84 kg ha−1 N was broadcast at planting and 84 kg ha−1 N was surface‐banded at the 8‐leaf growth stage. Applications of AN‐B, UAN‐B, and Urea‐B resulted in lower grain yields and leaf N concentrations than UAN‐I. These reductions were attributed to N immobilization and NH3 volatilization. Average yield reductions attributed to N immobilization were 8% on the Memphis soil and none on the Collins soil. Volatilization losses attributed to UAN‐B were 8 and 12% for the Memphis and Collins soils, respectively. Yield reductions attributed to NH3 volatilization from Urea‐B were 22 and 19% for the Memphis and Collins soils. Splitting the urea application increased yields relative to the Urea‐B treatment only on the Memphis soil. Surface application of limestone decreased Urea‐B yields.
Seed Yield and Seed Quality Response of Pensacola and Improved Bahiagrasses to Fertilization
Authors: Gates Roger N. , Burton Glenn W. 
Published: July 2010

AbstractAvailability of improved bahiagrass cultivars, such as ‘Tifton 9’, has increased the potential value of seed produced from bahiagrass. Seed yield response of improved entries to fertilizer inputs is unknown and the relationship of fertility to bahiagrass seed quality is poorly defined. Our objectives were to measure seed yield and seed quality response of three bahiagrass (Paspalum notatum Flügge var. saurae Parodi) entries, varying in forage yield, to fertilizer inputs. Bahiagrass was established in 1991 on Clarendon loamy sand (fine‐loamy, siliceous, thermic Plinthaquic Paleudults) near Tifton, GA. Forage production had been evaluated from 1992 to 1994. In 1995 and 1996, seed was harvested from ‘Pensacola’, Tifton 9 (T9), and RRPS Cycle 18 (T18) in July. Eight fertilizer treatments, identical to the 3‐yr forage yield study, included rates of 56, 112, 224, and 448 kg N ha−1; 25 and 49 kg P ha−1; and 47, 93, 139, 186, and 279 kg K ha−1. Seed yield was lower (P < 0.01) in 1995 than in 1996 and year and fertilizer treatment interacted (P < 0.01). Seed yield achieved with 224 kg N ha−1 and the lowest P and K rates was not improved by higher rates. Although fertilizer treatment and entry interacted (P < 0.01), optimal fertilizer inputs among entries were similar. Seed weight was greater in 1995 and was increased (P < 0.05) by spring application of 112 kg N ha−1 compared with 56 kg N ha−1, but not by higher rates. T18 seeds had greater (P < 0.05) emergence 7 or 14 days after planting (DAP) than Pensacola or T9. Emergence 14 DAP was greater with the highest N rates than the lowest rate. Emergence 35 DAP was only influenced by year (1996 > 1995). Moderate levels of N enhanced seed yield. Fertilizer treatment had no important effect on seed emergence or dormancy. Seed production and cumulative emergence of the three entries were similar.