bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subirrigated Meadow Response to Application of Nitrogen, Phosphorus, and Atrazine1
Authors: McConnell S. G. , Waller S. S. 
Published: July 2010

AbstractBotanical composition of native hay meadows throughout the True Prairie has shifted from predominantly native, warm‐season grasses to introduced, cool‐season species following mismanagement. To determine if a shift in composition back to warm‐season grasses and subsequent increased seasonal production could be achieved, atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] herbicide in combination with N and P fertilizer was evaluated on an eastern Nebraska subirrigated meadow. The soil is classified as a Lawet Variant fine sandy loam (fine‐loamy, mixed [calcareous], mesic Fluvaquentic Haplaquoll). Five rates of N (0, 45, 90, 135, and 180 kg ha−1), two rates of P (0 and 34 kg ha−1), and two rates of atrazine (0 and 2.2 kg ha−1) in factorial combination were arranged in a randomized complete block design. Atrazine and P were applied in late April to late May, and N was applied in early June in 1982 through 1984. A combination of 180 kg N ha−1 and 34 kg P ha−1 produced dry matter yields 95,101, and 77% greater than untreated plots in 1982, 1983, and 1984, respectively. Atrazine altered botanical composition from predominantly cool‐season grasses to predominantly warm‐season grasses. Changes in species composition by weight indicated a twofold increase in warm‐season yield. This shift in seasonal distribution of yield was accomplished without a reduction in total dry matter yield compared with plots recieving 180 kg N ha−1 in combination with 34 kg P ha−1.
Nitrogen Cycling in Seven Cool‐Season Perennial Grass Species1
Authors: Power J. F. 
Published: July 2010

AbstractAmong cool‐season grasses few comparisons have been made of the effects of N fertilization over an extended time period. An experiment was established at Mandan, ND, to study the effects of low (45 kg N ha−1) and excessive (225 kg N ha−1) fertilizer N rates for 9 yr on growth, N uptake, and fertilizer N accounted for in forage, roots, and soil inorganic N by seven temperate cool‐season grass species: western wheatgrass [Pascopyrum smithii Rybd. (Lõve)], crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.], intermediate wheatgrass [Elytrigia intermedia (Host) Nevski], smooth bromegrass (Bromus inermis Leyss.), Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], green needlegrass (Stipa viridula Trin.), and Garrison creeping foxtail (Alopecurus arundinaceus Poir). Total N concentrations of forage were increased with 225 kg N ha−1 annually only, and were often lowest for higher‐yielding species (B. inermis, A. desertorum, and E. intermedia). Cumulative total N uptake was usually greatest for those species plus P. smithii. Total N concentration and uptake in roots were increased by 225 kg N ha−1 annually, with few differences among species. Total N in roots gradually increased with the season, and by fall was double the spring levels. Minimum root‐N concentrations were at the 20‐ to 50‐cm soil depth. Soil inorganic N concentrations for the check and 45 kg N ha−1 rate were < 60 kg N ha−1 compared with 300 to 500 kg N ha−1 for the 225 N rate. For higher‐yielding species, 70 to 90% of the fertilizer N was initially accounted for in forage, roots, and inorganic N compared with 40 to 50% by the ninth year after extreme drought. At the higher fertilizer rate, 820 kg ha−1 fertilizer N was found in soil organic N. For all species and fertilizer N rates, 200 to 250 kg fertilizer N was not accounted for.
Modeling Cotton Fruiting Form Abscission1
Authors: Lieth J. H. , Arkin G. F. , Hearn A. B. , Jackson B. S. 
Published: July 2010

AbstractAbscission of cotton (Gossypium hirsutum L.) fruit and flower buds occurs even in well managed crops and influences subsequent fruit growth and development. Relationships that describe the abscission of flowering buds (squares), flowers, and fruit (bolls) were developed and incorporated into a process‐based cotton crop simulation model. These relationships are essential components of yield simulation models useful for management decision making. The abscission model developed is based on established hormonal and nutritional theories. Younger squares and bolls are predicted to abscise more readily than older ones. Abscission of bolls and squares depends on organ age, boll load, and environmental stresses. External stresses and internal competition for carbohydrates modify the probability of abscission multiplicatively. The effects of insects are approximated through a factor representing a uniform level of shedding throughout the growing season. Detailed fruiting site plant maps of greenhouse grown plants were used for model calibration. Simulations were carried out using input data collected at California, Texas, and Arizona. Simulated fruit development was in agreement with observed fruiting form counts and the frequency distribution for fruiting form age at abscission agreed with field observations.
The Influence of Chaff Extracts on the Germination of Spring Triticale1
Authors: Salmon D. F. , Helm J. H. , Duggan T. R. , Lakeman D. M. 
Published: July 2010

AbstractGermination inhibitors associated with the chaff of spring triticale (X Triticosecale Wittmack) could provide an important means of reducing sprouting caused by prolonged periods of rain during harvest. Eight spring triticales and two spring wheats (Triticum aestivum L. em. Thell) were grown on Navarre loam soil (fine clayey, montmorillonitic, frigid Aquic Cryoboroll) at Lacombe, Alberta and evaluated for germination inhibitors in their aqueous chaff extracts from 1982 to 1984. Each year, 200 spikes from each line were collected at harvest and air‐dried prior to storage at −20 or 20°C for 3 months. Only the chaff stored at −20°C was used for extract production. During 1982 and 1983, extracts from each line or cultivar were evaluated on their own seed stored at 20°C, whereas, in 1984, seed stored at both −20 and 20°C was used. Extracts were also compared with distilled water on the seed stored at 20°C from the sprouting susceptible wheat, ‘Fielder’ during 1983, as well as Fielder seed stored at −20°C, and seed from the sprouting resistant wheat line, ‘RL4137’, stored at 20°C during 1984. Extracts evaluated on seed that had been stored at 20°C for 3 months only briefly reduced germination in all lines except RL4137. Extracts evaluated on Fielder seed stored at −20°C or RL4137 seed stored at 20°C reduced germination up to 120 h. Regardless of the year, extract concentration, or storage temperature of the seed, the chaff extracts provided the greatest protection against germination when combined with high levels of seed dormancy. Selection for high levels of germination inhibitors in the chaff will be a valuable means of prolonging sprouting resistance in spring triticale.
Phenology of Dent Corn and Popcorn. II. Influence of Planting Date on Crop Emergence and Early Growth Stages1
Authors: Stevens E. J. , Stevens S. J. , Flowerday A. D. , Gardner C. O. , Eskridge K. M. 
Published: July 2010

AbstractDate of planting and date of crop emergence have been used as reference points for calculating heat sums used in modeling corn (Zea mays L.) phenology. An interactive agroclimatology program and service (AGNET) offered by the University of Nebraska, Lincoln (UNL), accumulates daily heat sums from the time of planting using data generated by an expanding automated network of meteorological stations. The objectives of this research were to evaluate current UNL‐AGNET procedures for modeling corn phenology with special reference to early development and, where necessary, develop and evaluate modified procedures. Time of planting and crop emergence were used separately as reference points for accumulating heat sums calculated using different procedures thereby addressing the impact of slow crop emergence and poor early seedling vigor associated with early planting. Daylength at emergence was included in regression models to investigate the likelihood of bias resulting from a delay in the date of planting. A 2‐yr phenology study incorporating three planting dates and daily and hourly heat sums was conducted in eastern Nebraska during 1982 and 1983. Data generated using staging criteria and regression models currently used in the UNL‐AGNET service were unsuitable for modeling early crop development; alternative procedures were developed using a modified staging criteria and hourly temperature data accumulated from the time of crop emergence. The phenologies of one dent corn cultivar (B73 X Mol7) and three popcorn cultivars (P410, P609, and Iopop 12) were studied using growth curve analysis. Response profiles (growth curves) differed significantly (P = 0.01) among cultivars and among planting dates. Growth curves derived using heat sums calculated using a base temperature of 5°C varied less between years when compared with other procedures for calculating hourly heat sums. A need was demonstrated to (i) account for the effect of planting date in corn phenology models, (ii) accumulate heat sums from either the time of crop emergence or preferably after stem elongation rather than from the time of planting, (iii) develop separate regression coefficients for different cultivars of corn, and (iv) develop hourly rather than daily heat sums when data are available from automated agro‐meteorological networks. Plant development response to day length variation across planting dates and the post‐emergence accumulation of thermal units did not fully account for differences in response profiles developed for early phenological development of four corn cultivars. Photoperiod effects appeared to be confounded with the impact of soil temperature on seedling emergence and growth prior to elongation of stem internodes.
Interactions of Maize Hybrids with Tillage Systems1
Authors: Newhouse K. E. , Crosbie T. M. 
Published: July 2010

AbstractThe use of conservation tillage for commercial production of maize (Zea mays L.) has expanded substantially in the past 10 yr. Few previous studies have compared the relative performance of a large number of hybrids in no‐tillage and conventional tillage cropping systems. In this study, 60 commercial hybrids were grown at two locations in Iowa in 1981 and 1982 to examine the interaction of commercial maize hybrids with no‐tillage and conventional tillage systems. Hybrid ✕ tillage interactions were not significant for any of the seven traits examined in a combined analysis of variance over tillage systems. Hybrid ✕ tillage ✕ environment interactions were significant for percentage emergence and mature plant height. Rank correlations of hybrid means from one tillage system to the other were significant and large, ranging from 0.66 to 0.94 for the agronomic traits measured, which was consistent with the lack of significant hybrid ✕ tillage interactions. No specific traits were of more importance for performance in no‐till than in conventional tillage. Also, no differential hybrid response to tillage systems, which was repeatable across environments, was observed. The study suggested that evaluation of performance in conventional tillage environments provided sufficient information to select among contemporary hybrids for use in conservation tillage environments.
Mono‐ and Double‐Cropped Wheat and Grain Sorghum under Rainfed and Irrigated Conditions1
Authors: Crabtree R. J. , Greenland R. G. , Mehdawi S. O. , Claypool P. L. 
Published: July 2010

AbstractSufficient amounts and distribution of rainfall are often the major limiting crop production factors in the southern Great Plains. This is especially true for summer crops whether grown in mono‐ or double‐cropping situations since these factors have significant impact on yields and profitability. This study was conducted at the Oklahoma Vegetable Research Station, Bixby, OK, from 1980 to 1984, on a Wynona silt loam soil (Cumulic Haplaquolls) with 0 to 1% slope. The objectives were to compare yields and net economic returns of mono‐ and double‐cropped wheat [Triticum aestivum (L.) em. Thell] and grain sorghum [Sorghum bicolor (L.) Moench] where all wheat was produced under rainfed conditions and where mono‐ and double‐cropped grain sorghum were produced under both rainfed and irrigated conditions. Over the 5‐yr period, rainfed, monocropped wheat yielded an average of 3498 compared to 2848 kg ha−1 for rainfed, double‐cropped wheat. Irrigated, conventionally tilled, monocropped grain sorghum yielded an average of 5650 compared to 4866 kg ha−1 for rainfed, conventionally tilled, monocropped grain sorghum. Irrigated, no‐till, double‐cropped grain sorghum yielded an average of 4976 compared to 3856 kg ha−1 for rainfed, no‐till, double‐cropped grain sorghum. Rainfed, monocropped wheat produced the highest net economic return per hectare of any of the five cropping systems. Net return from rainfed, conventionally tilled, monocropped grain sorghum was nearly equal to that of wheat. Irrigation increased the yields of mono‐ and double‐cropped grain sorghum 784 and 1120 kg ha−1, respectively. However, given these yields, the price of grain sorghum would have to increase from 0.10 to 0.25 and 0.19 dollars kg−1 for mono‐ and double‐cropped grain sorghum, respectively, before irrigation would become economically feasible.
Nitrogen Fertilizer Effects on Growth, Flowering, Oil Yield, and Yield Components in Meadowfoam1
Authors: Pearson C. H. , Jolliff G. D. 
Published: July 2010

AbstractMeadowfoam (Limnanthes alba Benth.) seed is a source of oil for use in industrial products and processes. Nitrogen fertilization typically has not increased seed yields of meadowfoam. Data are lacking for characterizing plant growth responses, flowering, honey bee (Apis mellifera L.) foraging, oil yield, and yield components of meadowfoam when fertilized with N. Thus, this field study was conducted in 1981 and 1982 on a Woodburn silt loam soil (fine‐silty, mixed, mesic Aquultic Argixeroll) to determine the effects of ammonium sulfate applied at 0 (control), 50 (50N), and 100 (100N) kg N ha−1. Increased vegetative growth of meadowfoam in response to spring application of N appears to be consistent. Nitrogen fertilization lowered canopy light transmittance and caused a differential flowering response from nonfertilized plants. Seeds per flower in the N‐fertilized treatments were not increased. Flower densities in N‐fertilizedtreatments in 1982 averaged 135% higher than in the control. Seed yields were not increased by N in 1981, but in 1982, seed and oil yields were increased by 113 and 99%, respectively, when N was applied. Oil content was consistently lower when N was applied, but this effect was more than offset by the higher seed yield in 1982. Because of the similar response of agronomic characters in 50N and 100N treatments, applications of 100 kg N ha−1 do not appear to be advantageous. Spring N fertilization of meadowfoam increased seed yield primarily through increased flower number.
Growth Analysis of Cottons with Differing Maturities1
Authors: Kohel R. J. , Benedict C. R. 
Published: July 2010

AbstractField and greenhouse experiments were conducted on cotton (Gossypium hirsutum L.) lines with differing maturities to determine what factors of plant growth contributed to early crop maturity and how these factors were related. Earliness was measured in terms of flowering, boll setting, length of boll maturation, and crop maturity. Additional measurements included plant growth and dry weight partitioning, productivity, and agronomic performance. Plant maturity was determined by time of flowering and length of boll maturation. Lines with the earliest crop maturities produced the lowest yields per plant. Performance of individual early maturing lines, such as 6 M, with improved agronomic properties, demonstrated the ability to increase early crop maturity with improved yield.
Growth Retardation of Bermudagrass with Metsulfuron Methyl and Sulfometuron Methyl1
Authors: Rogers J. N. , Miller E. M. , King J. W. 
Published: July 2010

AbstractOur primary objective was to determine optimum times and rates for applications of metsulfuron methyl (MSM) (methyl 2‐[(([(4‐methoxyd‐methyl‐l,3,5‐triazin‐2‐y1) amino] carbonyl) amino) sulfonyl] benzoate) and sulfometuron methyl (SMM) (methyl 2 [(([(4,6‐dimethyl‐2‐primidinyl) amino] carbonyl) amino) sulfonyl] benzoate) to reduce mowing requirement without adversely affecting the aesthetic value of the bermudagrass [Cynodon dactylon (L.) Pers.] turfgrass. Field studies were conducted on mature bermudagrass lawn turf grown on a Captina silt loam soil (fine‐silty, mixed, mesic Typic Fragiudalt). Results of 1982 and 1983 experiments showed that MSM alone produced much less growth reduction than a combination of MSM and SMM. The combination at rates of 35 + 35 and 70 + 70 g ha−1 and higher produced good growth suppression for 6 to 8 weeks followed by a flush of growth, but excessive discoloration injury especially when repeated at 5‐week intervals. In 1984 the combination applied at 8.8 + 8.8 on 24 May, 17.5 + 17.5 on 28 June, and 35 + 35 on 2 August provided excellent growth retardation (70% mowing reduction) all season with only very slight injury. The influence of irrigation and N fertilization was minimal.
Variation between Soybean Cultivars in Vesicular‐Arbuscular Mycorrhiza Fungi Colonization1
Authors: Heckman J. R. , Angle J. S. 
Published: July 2010

AbstractThe potential exists for soybean [Glycine max (L.) Merr.] cultivars to be differentially colonized by indigenous soil populations of vesicular‐arbuscular mycorrhiza (VAM) fungi. A pot experiment (Typic Palendults) was conducted in a greenhouse to assay the colonization of various soybean cultivars by VAM fungi. Relative colonization of 15 soybean cultivars at two P levels was determined. Individual root systems were compared for the percentage of roots colonized by VAM fungi using an acid fuchsin‐lactic acid staining procedure. Colonization was shown to vary significantly with cultivar. The cultivar colonized by the highest percentage was the nonnodulating isoline of Clark rj1 rj1 with 80% of root segments examined being colonized. ‘Williams 82’ exhibited the lowest percentage (57%) of colonization by VAM fungi. The addition of P to the soil reduced the percentage of colonized roots from 68 to 64%, and there was no cultivar ✕ P interaction.
A Hot‐Wire Technique for Girdling Stems and Petioles of Herbaceous Plants1
Authors: Dewey Steven A. , Chilcote David O. , Appleby Arnold P. 
Published: July 2010

AbstractGirdling is often useful in studying translocation of herbicides, plant‐growth regulators, and natural plant components. A hot‐wiretechnique for girdling petioles and stems of herbaceous broadleaf plants using two girdling instruments was studied. One apparatus used AC current to heat a loop in a copper wire. Current was regulated with a rheostat. The other device was a battery‐powered medical cautery instrument with a modified nichrome wire loop. With either device, the hot wire was passed back and forth along a 20‐ to 30‐mm section of petiole or stem until cellular collapse was evident, usually 30 to 60 s. Girdling essentially eliminated basipetal movement of 14C‐assimilate but did not reduce acropetal translocation of simazine (6‐chloro‐N,N′‐diethyl‐1,3,5‐triazine‐2,4‐diamine), an apoplastically mobile herbicide, in tall morningglory [Ipomoea purpurea (L.) Roth]. The method is quick and allows precise placement of girdles
Mefluidide Effects on Forage Quality of Crested Wheatgrass1
Authors: Haferkamp M. R. , Miller R. F. , Sneva F. A. 
Published: July 2010

AbstractCrested wheatgrass, (Agropyron desertorum [Fisch.] Schult), a valuable spring forage in semiarid environments, produces stiff reproductive shoots that become unpalatable and are of poor nutritive quality. Mefluidide (N‐[2,4‐dimethyl‐ 5{[(trifluoromethyl)sulfonyl] amino} phenyl]acetamide), a plant growth regulator, has the potential to reduce reproductive shoots and improve nutritive quality. Mefluidide was applied to crested wheatgrass, which was grown on coarse‐loamy, mixed, frigid Orthid Durixerolls in May 1982 and 1983, at 0.14, 0.28, and 0.42 kg a.i. ha−1. Herbage yield, density of reproductive shoots, and concentrations of ash, acid insoluble residues, total N (crude protein), in vitro digestible organic matter (IVDOM), and neutral detergent fiber (NDF) in accumulated forage during July through October were determined each year. Reproductive shoot density was reduced by mefluidide up to 91% in both years. The reduction in reproductive shoot density was accompanied by a 20 to 60% decrease in dry matter yields. Ash contents increased 50 to 70 g kg−1 with mefluidide application. A relatively large portion of the ash was acid insoluble residue (silica) and may have been the result of soil contamination on leaves of treated plants. Mefluidide also increased crude protein 18 to 19 g kg−1 and IVDOM 30 to 40 g kg−1, and decreased NDF 50 to 80 g kg−1. The greatest changes occurred with the 0.28 and 0.42 kg ha−1 rates. Major benefits of mefluidide applications include increased forage quality and decreased stemminess.
Evapotranspiration and Yield Comparisons among Soil‐Water‐Balance and Climate‐Based Equations for Irrigation Scheduling of Sweet Corn1
Authors: Braunworth William S. , Mack Harry J. 
Published: July 2010

AbstractAs water for crop production becomes limited and costs of water increase there is a need for more accurate irrigation scheduling. Irrigation scheduling can be improved with reliable and rapid estimates of crop evapotranspiration (ET). The use of three climatebased equations and the soil‐water‐balance equation for estimating sweet corn (Zea mays L. ‘Jubilee’) ET for irrigation scheduling were compared in a 2‐yr field study on a mixed, mesic Cumulic Ultic Hapoxeroll soil. The three climate‐data‐based equations used were the Food and Agriculture Organization of the United Nations (FAO) modified Penman and the FAO and Soil Conservation Service (SCS) Blaney‐Criddle equations. Five irrigation levels ranging from 0 to 100%, with the 100% level intended to refill the root zone to field capacity, were all proportionately irrigated when approximately 50% of the available water was depleted in the 100% level as measured with a neutron meter. A sixth treatment in this randomized complete block experiment was irrigated with the amount of water equivalent to the crop ET estimated by the FAO modified Penman (M PEN) equation, when the crop ET had accumulated to 50% of the available soil water. The crop ET estimated by the soil‐water‐balance equation in 1984 was 481 and 447 mm for the 100% level and for plots irrigated according to the M PEN equation, respectively. In 1985 these ET estimates were 506 and 488 mm, respectively. The crop ET in 1984 was 404, 372, and 374 mm as estimated by the M PEN, FAO, and SCS Blaney‐Criddle equations, while in 1985 these equations estimated 450,448, and 379 mm, respectively. Yield differences were not significant between plots irrigated according to the M PEN equation and the irrigation levels of 50% or more in both years. Calculations indicated that the lower estimates of ET by the FAO and SCS Blaney‐Criddle equations, if used to schedule irrigations, would not be expected to cause yield decreases.