bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cassava‐Cowpea and Cassava‐Peanut Intercropping. III. Nutrient Concentrations and Removal1
Authors: Mason S. C. , Leihner D. E. , Vorst J. J. 
Published: July 2010

AbstractLittle is known about the influence of intercropping cassava (Manihot esculentaCrantz) with cowpea [Vigna unguiculata(L.) Walp] or peanut (Arachis hypogueaL.) on nutrient concentrations of plant tissue or nutrient removal by the crops. The objectives of this study were to (i) compare the nutrient concentrations in plant parts of cassava, cowpea, and peanut in intercropping systems to those in sole cropping systems, and (ii) determine uptake of N, P, and K of cassava‐cowpea and cassava‐peanut intercropping systems as compared with the sole cropping systems. Cassava, cowpea, and peanut were grown as sole crops and intercrops on a Typic Dystropept soil at Santander de Quilichao, Colombia, in 1981 and 1982. Intercropping with cowpea resulted in 0.8, 0.6, and 0.3 g kg−1lower P concentration [P], and 5.2,4.9, and 2.9 kg 1lower [N] in cassava stems, leaves, and storage roots, than resulted from sole‐cropped cassava 50 days after planting. Intercropping had no influence on [N], [P], and [K] of cassava at later harvest dates or of cowpea at any harvest date. Similar results occurred when cassava was intercropped with peanut, although peanut was a less vigorous competitor with cassava for P than was cowpea. The cassava‐cowpea and cassava‐peanut intercropping systems removed 3.0 to 7.5 g m 2more N, 0.30 to 0.47 g m 2more P, and 2.5 to 5.1 g m more K than sole‐cropped cassava. Results suggest that these intercropping systems remove more nutrients than comparable sole crops, which leads to more rapid mining of natural soil fertility or the need for higher fertilizer application rates.
A Microcomputer‐Controlled Leafweighing System1
Authors: McCaig T. N. 
Published: July 2010

AbstractA completely, automated weighing system was built to facilitate large numbers of repetitive wheat‐leaf weighings required in a drought program (wheat: Triticum aestivumL.). Leaf samples (up to 265) were clipped to holders suspended from hangers on a conveyor chain. The samples were then repetitively weighed (three samples per minute) throughout the day to determine individual water‐loss rates. An inexpensive microcomputer controlled all operations including movement of the conveyor chain, transfer of samples to and from the balance, taring and weighing operations, and data storage. With minor modifications this weighing system can be easily applied to other types of routine weighing needed in agricultural research.
Response of Corn to Tillage and Delayed Irrigation1
Authors: Porro I. , Cassel D. K. 
Published: July 2010

AbstractIrrigation in humid regions is often delayed based on forecasted rainfall or due to labor shortages or equipment problems. The effects of tillage and delayed irrigation on corn (Zea mays L.) were investigated in 1982 and 1983 on a Norfolk loamy sand (Typic Paleudult) with a tillage pan. Irrigation treatments were: optimum irrigation when tensiometer measured soil water pressure at the 25‐ or 30‐cm depth was −40kPa; 2‐day and 4‐day delays after irrigation was needed; and a nonirrigated control. Each irrigation treatment was superimposed on land prepared by two tillage treatments: (i) conventional and (ii) subsoiling and bedding. Delayed irrigation during a wet growing season (1982) had little effect on corn growth. Delayed irrigation during the dry growing season (1983) reduced plant height, leaf area, biomass, and grain yield on conventionally tilled soil but only grain yield on subsoiled plots. With a 4‐day irrigation delay, grain yields were reduced 29% below the 10.22 Mg ha−1 yield for conventional tillage but only 11% below the maximum of 10.56 Mg ha−1 for subsoiling. Irrigation in 1982 increased mean grain yield of all three delay treatments by 23 and 1% for conventionally tilled and subsoiled treatments, respectively. In 1983, these increases were 314 and 18%, respectively. A 1‐yr subsoiling carryover (1983) resulted in a yield of 8.89 Mg ha−1 vs. a current‐year subsoiled yield of 10.68 Mg ha−1. A 2‐yr carryover (1982) resulted in a yield of 9.60 vs. 10.60 Mg ha−1 from current year subsoiling.
Studies of Intact Shoot‐Root Systems of Field‐Grown Winter Wheat. I. Sampling Techniques1
Authors: Belford R. K. , Rickman R. W. , Klepper Betty , Allmaras R. R. 
Published: July 2010

AbstractThe yield component most closely related to wheat (Triticum aestivum L. em. Thell.) yield in the dryland farming area of the Pacific Northwest is heads per unit area. Tiller survival determines the head population and is therefore a major yield determining factor. A study relating tiller survival to tiller rooting required a sequential sampling of intact shoot‐root systems of field grown plants. As no technique to provide the required samples was found in the literature, a new procedure was devised. Square metal tubes, 0.18 by 0.18 by 1.1 m with removable side, were constructed of 16‐gauge steel. These tubes were forced into the ground with a hydraulic coring machine immediately after emergence of winter wheat (var ‘Stephens’) planted in 0.18‐m rows on 14 Oct. 1981 in field plots on a Walla Walla silt loam (mixed, mesic Typic Haploxerolls). Thermocouples and tensiometers at 0.2‐, 0.4‐,0.6‐, and 0.8‐m depths showed that soil temperatures were not significantly different between the tubes and adjacent field soil, but soil in some tubes was significantly wetter (higher water potential) than adjacent field soil during winter. Tubes were extracted from the field on 23 February, 17 March, 19 April, and 1 June. The removable side was taken off and a fine spray was used to wash soil from the roots. Washed intact plants were floated in water in a shallow tray to separate individual plants, tillers, and their associated roots. These separations were not successful for deep roots for the June sampling date. This technique permits collection of data on rooting habits of plants at different times in the growing season, on associations between shoots and intact field‐grown root systems, and on details of root branching patterns under field conditions.
Nitrogen Fertility and Sucker Control Method on Maryland Tobacco Yield, Value, and Quality1
Authors: Bruns H. A. 
Published: July 2010

AbstractThe quality of Maryland tobacco as influenced by N fertility and sucker‐control method is not well documented. Four N‐fertility rates (67.2, 134.4, 201.6, and 268.8 kg ha−1 N) along with five methods of sucker control [topped nonsuckered, topped handsuckered, KMH (K salt of 1‐2‐dihydro‐3,6‐pyridazinedione‐meleic hydrazide), Prime + {2‐chloro‐N‐[2‐dinitro‐4‐(trifluoromethyl)‐phenyl]‐N‐ethyl‐6‐fluorobenzenemethanamine}, and OST‐85 (1‐decanol plus 1‐octanol mixture)] were imposed on the tobacco (Nicotiana tabucum L.) cultivar MD 609 in 1983 and 1984. Yield, value, burn duration, filling capacity, total alkaloids of cured leaf, plus NO3‐N and total N at topping, harvest, and after curing were evaluated. Drought during July 1983 adversely affected most quality factors. Increasing N fertility increased yield, total alkaloids, total N, and NO3‐N while lowering burn duration, filling capacity, and value. Nitrogen‐fertilizer rates above 134.4 kg ha−1 N appear to have no benefit. Chemical sucker control increased yields and value with no adverse effect on quality or interaction with the different N‐fertility rates.
Atrazine Effects on Tensile Strength of Centipedegrass Sod1
Authors: Turner D. L. , Dickens R. 
Published: July 2010

AbstractCentipedegrass [Eremochloa ophiuroides (Munro) Hack.] sod has become more in demand over the past decade, leading producers to attempt to speed production. An increase in the use of the herbicide atrazine [6‐chloro‐N‐ethyl‐N'‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] for weed control has been one result. Numerous sod producers in the Southeast have experienced difficulty harvesting sod due to inadequate tensile strength. The object of this study was to determine the effects of atrazine on the tensile strength of centipedegrass sod. The experiment was conducted during 1982, 1983, and 1984 at Auburn, AL, on a Dothan sandy loam (Plinthic Paleudult) and during 1982 and 1983 at Tuskegee, AL, on a Gilead sandy loam (Aquic Hapludult) and a Leaf silt loam (Typic Albaquult), respectively. Atrazine was applied to centipedegrass at 0.6, 1.1, and 2.2 kg ha−1 rates at 2‐ and 4‐week intervals during the growing season. Visual injury ratings were taken in July, September, and May, and sod tensile strength measurements were taken in September and May following applications. Visual observations indicated that injury was increased as atrazine rates and application frequencies increased. Less Injury occurred in 1983 at both locations. Visual injury ratings were not consistent with sod tensile strength measurements. Measurements of sod tensile strength revealed that increasing rates of atrazine reduced the tensile strength in a linear fashion. Injury was greater with the 2‐week application interval. Reduction of tensile strength was more evident with sod harvested in September than in May at both locations. Sod tensile strength of untreated centipedegrass was higher during September than during the following May and at the Auburn location.
Nitrogen Transfer from Siratro to Kleingrass: Competition for Mineral Nitrogen and Isotopic Fractionation1
Authors: Ismaili M. , Weaver R. W. 
Published: July 2010

AbstractAvailability of combined N limits productivity of Kleingrass (Panicum coloratum L.) when grown with siratro (Macropitilium atropurpureum D.C. Urb.). An experiment was undertaken in a glasshouse to measure the quantity of N transferred from siratro to Kleingrass and the competitive relationship between siratro and Kleingrass for mineral N. Plants were grown for 187 days in pure stand and in mixture and fertilized with two rates of 15N‐labelled (NH4)2SO4 provided in split applications. The only sources of N to the plants was from the labelled fertilizer and biologically fixed N by siratro. Kleingrass obtained approximately 60% of the N recovered when grown with siratro at either rate of N fertilization. Siratro transferred biologically fixed N to Kleingrass, which accounted for 14 and 5% of the total N in the Kleingrass for the low and high rates of N fertilization, respectively. Isotopic fractionation of N occurred between shoots and roots of Kleingrass and was not a result of fractionation during N uptake. Caution needs to be exercised in assuming isotopic fractionation does not influence results of experiments using isotope dilution to measure N fixation.
Greenness‐Leaf Area Index Relationships of Seven Row Crops1
Authors: Redelfs M. S. , Stone L. R. , Kanemasu E. T. , Kirkham M. B. 
Published: July 2010

AbstractRemote sensing technology has potential for nondestructive estimation of green leaf area index (LAI). We applied the greenness transformation to ground‐based reflectance data taken over seven crops [sweet and field corn, Zea mays L.; grain sorghum, Sorghum bicolor (L.) Moench; pearl millet, Pennisetum americanum (L.) Leeke; pinto bean, Phaseolus vulgaris L.; soybean, Glycine max (L.) Merr.; and sunflower, Helianthus annuus L.] grown on Eudora silt loam soil (coarse‐silty, mixed, mesic Fluventic Hapludoll) to determine reflectance‐LAI relationships, and to see if those relationships were crop specific or could be applied more generally to several crops. Spectral reflectance data were collected with a radiometer equipped with four wavelength bands that simulated the Landsat multispectral scanner bands. The coefficients for brightness and greenness were calculated by using reflectance data and published calculation procedures. Greenness coefficients for the reflectance data for all crops were very similar. Models were developed that related greenness (calculated by using the individual crop greenness coefficients or the coefficients developed from combined data of all crops) and field estimates of green LAI. All models were significant (P<0.0001) and linear, with the regression coefficients equal to what we termed the crop factor. Intercepts were not significantly different from zero (P>0.05). The combined greenness coefficients were not significantly different than individual crop coefficients in relating greenness to field‐estimated LAI. The crops were grouped into grass or broadleaf to determine general crop factors. It made no significant difference whether the individual crop factor or the combined crop factor (for grass, 0.197; for broadleaf, 0.117) was used in developing the greenness‐estimated LAI that was related to field‐estimated LAI. This study illustrated that the greenness coefficients developed for each of seven row crops were very similar and the regression coefficients from the linear relationship between LAI and reflectance greenness were very similar within the grass crops and within the broadleaf crops.
Yield and Biochemical Response of Sugarbeet to Benomyl1
Authors: Smith G. A. , Martin S. S. 
Published: July 2010

AbstractTwo field studies were conducted to determine the effects of the systemic fungicide benomyl [methyl 1‐(butylcarbamoyl)‐2‐benzimidazolecarbamate] applied at protectant levels to the foliage of sugarbeet (Beta vulgaris L.), on yield components, recoverable sucrose, and six root extract chemical constituents. In the initial study (1980 and 1981), six benomyl applications (271 g a.i. ha−1, at 2‐week intervals beginning in late June) to disease‐free sugarbeets significantly increased yield components and decreased amino N, total N, and betaine. The objective of the second study (1982–1984) was to determine the effect of timing and number of benomyl applications during the growing season. In each year, five benomyl treatment regimes, ranging from single applications to six sequential applications, were evaluated for their effects. All non‐sucrose chemical component means across cultivars decreased as a result of benomyl treatment. These reductions were consistent and statistically significant for total N, amino N, and betaine. Means for sucrose, purity, and root weight increased in response to benomyl in 1980 and 1981 although not significantly so for sucrose. There was a significant year‐effect on changes in yield components and lack of consistency for any given treatment on extract chemical composition. Thus, these data did not point to a specific physiological basis for the observed effects.
Growth and Yield Response of Solid‐Seeded Soybean to Early Season Stand Reduction1
Authors: Torri K. , Vasilas B. L. , Carmer S. G. , Smyth C. A. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] stands can be reduced by hail storms, soil crusting, poor seed vigor, and other factors. Little information is available on the response of solid‐seeded (drilled) soybean to stand reduction. Four experiments were conducted at the University of Illinois on a Drummer silty clay loam (Typic Haplaquoll) in 1984 and on a Flanagan silt loam (Aquic Argiudoll) in 1985 to evaluate the growth, yield, and yield component response of solidseeded soybean to early season stand reduction. Four levels of stand reduction (0, 25, 50, 75%) were imposed at two growth stages (V3, V6) on ‘Hobbit’ (determinate, semidwarf, Maturity Group III) and ‘Pella’ (indeterminate, normal height, Maturity Group III) soybean, planted on 16 May 1984 and 13 May 1985 in 0.175‐m‐wide rows with a seeding rate of 560 000 seed ha−1. With a few exceptions, the growth stage at which stand reduction treatments were imposed did not affect the parameters measured. Seed yields of Pella in 1985 were constant over a population range of 130 000 to 468 000 plants ha−1. Averaged across the two growth stages, 75% stand reduction, which reduced the population to an average of 118 000 remaining plants ha−1, reduced yields of Hobbit in 1984 and 1985, and Pella in 1984 by 11, 14, and 15%, respectively. Across experiments, a population of 308 600 plants ha−1 was found to be adequate for maximum yields. Yield reductions in Hobbit were associated with decreased seed number; yield reductions in Pella were associated with decreased seed size. Seventy‐five percent stand reduction delayed canopy closure and increased branch number per plant in all cases, and increased internode number per plant in Pella.
Soybean Specificity for Bradyrhizobium japonicum Strain 1101
Authors: Howle P. K. W. , Shipe E. R. , Skipper H. D. 
Published: July 2010

AbstractThe specificity of six Maturity Group VII soybean [Glycine max (L.) Merr.] cultivars to inoculation with Bradyrhizobium japonicum Strain USDA 3I1b110 was measured relative to indigenous B. japonicum populations in 1981 and 1982 in two environments in South Carolina. The Clemson experiment was on a Chewacla soil (fine‐loamy, acid, thermic Aquic Fluventic Dystrochepts) in 1981, and on a Toccoa soil (coarse‐loamy, mixed, nonacid, thermic Typic Udifluvents) in 1982. The Florence experiments were on a Norfolk soil (fine‐loamy, siliceous, thermic Typic Paleudults). Top dry weight and plant N content, and the number and dry weight of nodules per plant were determined at the R5 growth stages. Seed yield and N content were also measured. No differences were detected (≤0.05) due to inoculation for any variable studied. Genotypic differences occurred in harvest yield rankings, with three of the four tests having similar cultivar rankings. Nodule occupancy was determined by serological assay against 15 antisera. Serogroup 110 was not recovered from the Clemson sites and ≤ 8% from the Florence site. Serogroup 31 was the predominant, indigenous strain identified at both locations and occupied 9 to 34% of the nodules. Nodule occupancy by a less efficient serogroup, 31, is a limiting factor to soybean production. No specificity was detected between Strain 110 and six soybean cultivars.
Fermentation Inhibition of Forage and Sweet Sorghum Silages Treated with Acrylic or Maleic Acid1
Authors: Hill N. S. , Posler G. L. , Bolsen K. K. 
Published: July 2010

AbstractOne source of biomass for conversion to liquid fuel is sweet sorghum [Sorghum bicolor (L.) Moench]. Its potential use as an alcohol feedstock is limited by a harvesting season too short to supply batch fermenters with a constant source of substrate. One solution is to conserve sugars by ensiling the crop with fermentation inhibitors. ‘Rio’, ‘Dale’ and DeKalb ‘FS25A’ sorghums were harvested at physiological maturity and treated with 2.5 or 5.0 g of acrylic or maleic acid per kilogram of herbage. Treated herbage was analyzed for glucose, fructose, sucrose, dry matter, and protein concentration. After 130 days fermentation, silages were analyzed for these factors plus ammonia, lactic acid, and volatile fatty acids. Dale and FS25A herbage had proportionately higher sugar monomers and lower total sugar conservation than Rio. Sugar recovery increased from less than 100 g kg−1 to 987 g kg−1 with acrylic acid application but was unaffected by maleic acid. Both acid treatments decreased lactic and acetic acid production, while silages treated with acrylic acid had higher ammonia and propionic and valeric acid production, and pH. Ammonia production decreased in silages receiving maleic acid. These data indicate that sweet sorghum treated with acrylic acid can be stored as silage without appreciable sugar loss.
Long‐Term Yield Data Used to Define Production Areas for Hard Red Spring Wheat1
Authors: Campbell L. G. 
Published: July 2010

AbstractAn effective cultivar development or testing program depends on the identification of nursery locations and testing sites that are representative of those encountered in commercial production. Defining unique production areas within a region often is complicated by the inability of the researcher to accurately determine the factors influencing crop response. Long‐term (1919–1983) county yield data for spring wheat (Triticum aestivum L.) were used as a basis for defining and characterizing production areas within North Dakota. Cluster analysis indicated that the state reasonably could be divided into five areas. These areas were characterized by differences in mean yield, standard deviation, range of yields, and stability of yield as measured by regression of county yield upon the state mean yield. A regression equation relating yield to distance north and east of the southwest corner of the state was used to construct yield isolines. The areas delineated by the cluster analysis and the pattern of the isolines were consistent with general physiographic areas of the state and climatic gradations. It was demonstrated that long‐term county yield data can provide a basis for defining production areas.
Soil Water Deficit Effect on Yield, Leaf Area, and Net Assimilation Rate of Three Forage Grasses: Crested Wheatgrass, Smooth Bromegrass, and Altai Wildrye1
Authors: Bittman S. , Simpson G. M. 
Published: July 2010

AbstractAnnual forage yield in the northern Great Plains depends primarily on quantity and temporal distribution of precipitation. This study was conducted to examine the effect of water deficit on yield, leaf area, and net assimilation rate (NAR) of three forage grasses under field conditions. The grasses, smooth bromegrass (Bromus inermis Leyss.) (Br), Altai wildrye [Leymus angustus (Trin.) Pilger] (AWr), and crested wheatgrass [Agropyron cristatum (L.) Beauv. spp. pectinatum (Bieb.) Tzvel.] (CWg), were chosen because of their contrasting morphologies. The grasses were grown on deep black soil (Melfort silty clay, Typic Cryoboroll) under two moisture regimes: DRY plots were covered by rain‐out shelters starting at the end of May, and IRR plots were watered when soil water potential averaged −0.07 MPa. Crested wheatgrass expanded leaf area more rapidly in spring than Br and AWr, and responded to increasing soil water deficits by sharply reducing its leaf area through senescence of older leaves. Altai wildrye developed its leaf area slowly, probably because more dry matter was required to produce a unit of leaf area. It responded to soil water deficit by reducing rate of leaf expansion. Smooth bromegrass developed its leaf area rapidly although somewhat later than CWg. The effect of soil water deficit on leaf expansion was less in Br than AWr, and its effect on reduction of leaf area through leaf senescence was less in Br than CWg. In late May, AWr yielded less than CWg but more than Br. At the end of June, yield of CWg was greater than both Br and AWr in 1983, and greater than AWr but similar to Br in 1984. Altai wildrye recovered most rapidly after clipping among the species in both years but yielded more regrowth only in 1984. No interaction was found between moisture regime and species for either leaf area or yield on any of the sampling dates, probably because soil water deficits developed gradually under the conditions of this experiment, thus minimizing the effects of the different growth patterns. Soil water deficit affected leaf area proportionately more than NAR in AWr and CWg but not in Br. The findings suggest that the relative effect of drought on these two yield components depends on species and environment.