bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Soil Water on Rhizobium japonicum Infection, Nitrogen Accumulation, and Yield in Bragg Soybeans1
Authors: Hunt P. G. , Wollum A. G. , Matheny T. A. 
Published: July 2010

AbstractLow soil water contents may be involved in the lack of success of soybean inoculation in southeastern U.S. soils having high indigenous populations of Rhizobium japonicum. This study was conducted to assess the effect of soil water on the inoculation, biomass, N accumulation, and yield of soybean [Glycine max (L.) Merr.]. ‘Bragg’ soybeans were inoculated with 108 cells/cm row of R. japonicum (strain 110) and grown under both irrigated and nonirrigated conditions on a Norfolk loamy sand (Typic Paleudult) in a split plot design. Rainfall maintained the surface soil above −250 mb matric potential until the late flowering stage of growth. Subsequently, a seasonal drought created treatment differences between irrigated and nonirrigated plots resulting in a twofold increase in seed yield due to irrigation (3,160 vs. 1,682 kg/ha). Inoculation increased the percentage infection by strain 110 from practically 0% background to about 20%. Inoculation increased growth and total N accumulation in pods, petioles, and leaves of Bragg soybeans under irrigated conditions. Under nonirrigated conditions, the increased infection of strain 110 appeared to induced a negative response in the vegetative growth of Bragg soybeans. Nitrogen concentration was also significantly lower in the leaves and pods of nonirrigatedinoculated plants. These differences were not observed in N content of the mature seed, and inoculation did not significantly affect seed yield. These findings indicate that R. japonicum strain ✕ environment interactions may be important for soybean growth and yield in the southeast United States.
A Visual Indicator of Physiological Maturity in Soybean Plants1
Authors: TeKrony D. M. , Egli D. B. , Henson G. 
Published: July 2010

AbstractPhysiological maturity (PM) represents an important growth stage of crop plants, since it is normally associated with maximum accumulation of dry seed weight and yield. Physiological maturity of an individual soybean (Glycine max (L.) Merrill) seed or pod occurs when the seed or pod is completely yellow; however, indicators of PM on a whole plant basis are not available. This investigation was conducted to relate several visual indicators of soybean pod development to PM and yield of field populations. Plants of three cultivars (‘Williams’, ‘Kent’, and ‘Essex’) were grown in a Maury silt loam soil (Typic Paleudalfs, fine, mixed, mesic) in 1977 and 1978 and harvested when 50% of the population had reached or exceeded the following growth stages: 1) a completely expanded green pod at one or more of the four uppermost nodes, 2) one yellow pod per plant, and 3) one normal pod on the main stem that has reached its mature pod color (growth stage R7). A check harvest was made after full maturity. In 1979, seven cultivars representing maturity groups OO to V and both determinant and indeterminate growth habits were grown in the same soil type and harvested at growth stage R7 and at full maturity.Plants harvested at the green pod growth stage exhibited significantly smaller seed and lower yield compared to those harvested at full maturity. Even though there was no significant reduction in seed size and yield for plants harvested at the yellow pod growth stage, in 1978 there was a consistent trend across cultivars for lower yields at this harvest. There was no reduction in seed size or yield for plants harvested at growth stage R7 in all 3 years compared to harvests at full maturity. Growth stage R7 (one mature pod per plant) was a more accurate indicator of PM than the yellow pod growth stage (one yellow pod per plant), since a greater percentage of pods (64%) and seed (55%) had reached or exceeded complete yellow coloration indicating that those pods and seed were physiologically mature. The appearance of one normal pod on the main stem that has reached its mature pod color (growth stage R7) represents an accurate, easy to recognize visual indicator of PM. This criteria should provide farmers, researchers, and others with a useful tool for determining PM for a single plant or a field population.
Recoverability of Cotton Following Simulated Hail Damage1
Authors: Smith C. Wayne , Varvil J. J. 
Published: July 2010

AbstractMany areas of the so‐called cotton belt frequently receive hail sufficient to cause measurable damage to cotton (Gossypium hirsutum L.). The indeterminant growth habit of cotton allows for varying degrees of recoverability from hail damage depending upon the stage of growth of the plants when damaged and the severity of damage.Research was initiated in 1977 to evaluate the recoverability of cotton from simulated hail damage. These tests were conducted at three locations in Arkansas representing several silt loam soils with one site being severely infested with verticillium wilt [Verticillium albo‐atrum (Reinke and Berth)].Upon developing the 4th, 7th, and 10th true leaves, plants were hand cut to immediately above the cotyledonary node (CC type damage) or immediately above the second true leaf node (C2). At the Marianna location only, plants with 10, 12, and 14 true leaves also were damaged (C5 and C7) to assess recoverability of plants just prior to flowering, approximately at flowering, and just after flowering. The field design was a randomized complete block with four replications of plots 12 to 15 m in length.The degree of recoverability decreased as the severity of damage increased or as the same damage was applied to older plants. Plants infested with Verticillium wilt did not recover from simulated hail damage as well as plants at the other two locations indicating an accumulative effect of yield limiting stresses. Stepwise regression analysis indicated that 79% of the variability in seedcotton yields following the early season treatments could be accounted for by the number of nodes removed and the stage of plant development at the time of injury. Recoverability of plants damaged when near flowering could not be predicted by the number of nodes removed and/or stage of growth. Quality characteristics of the fiber were affected little.
Influence of Windbreak‐shelter on Soybean Production under Rainfed Conditions1
Authors: Ogbuehi S. N. , Brandle J. R. 
Published: July 2010

AbstractResearch indicates that a combination of windbreak and irrigation gives significant soybean yield increases in comparison to an irrigated open field. Little data is available to determine the yield advantage of soybean production under sheltered and rainfed conditions. The field study reported here was conducted at the University of Nebraska Field Laboratory, Mead, Nebraska, during 1978 and 1979 growing seasons to determine the influence of windbreak‐shelter on soil water content and soybean [Glycine max (L.) Merr.] yield under rainfed conditions. Shelter from wind was provided by a system of east‐west oriented shelterbelts, 6 m high, 60% dense, and consisting of green ash (Fraxinus pennsylvanica L.), Austrian pine (Pinus nigra Arnold), and eastern red cedar (Juniperus virginiana L.). The prevailing winds in Nebraska during the summer months come mainly from the south. The soil was a Typic Argiudoll.There were no statistically significant differences (P = 0.05) between treatments in available soil water and plant water use. In spite of this, sheltered soybeans had higher leaf water potential and stomatal conductance, and lower leaf temperature. These differences between treatments were attributable, entirely, to shelter‐induced modification of the growing season microclimate. Leaf area index, dry matter production, and bean yield were significantly increased in shelter during both years. Bean yield in shelter was 20 and 26% higher than in exposed plots in 1978 and 1979, respectively. Bean production per ha‐cm of water used in 1979 was 58 kg for sheltered soybeans and 47 kg for those in exposed plotsResults of this study indicated that under rainfed conditions, increased water‐use efficiency, and significant increases in bean yield can be expected from sheltered soybeans.
Canopy Temperatures, Water Use, and Water Use Efficiency of Corn Genotypes1
Authors: Mtui T. A. , Kanemasu E. T. , Wassom C. 
Published: July 2010

AbstractIt is desirable to describe and characterize physiological properties of corn (Zea mays L.) genotypes that will permit a basis for selecting genotypes. The objective of this field study was to compare two hybrids (Mo17 ✕ B73, A619 ✕ A632) and their respective inbred parents under irrigated and nonirrigated conditions. Measurements of canopy temperature, stomatal diffusive resistance, xylem water potential, leaf area index, ear dry weight, and grain yield were determined. Water use was determined from neutron moderation measurements of the soil‐water profile. The soil was a fine silty, mixed mesic, Pachic Haplustoll that holds approximately 250 mm of plant available water.Hybrids had higher grain yield, water use, and water use efficiency than the inbred parents under both irrigated and nonirrigated conditions. Estimates of water use by both hybrids and inbreds were greater for irrigated than for nonirrigated treatments. Early ear dry weight appeared to be an indicator of final ear weight, and in this particular study, was an indicator of final grain weight. Canopy temperatures were cooler for hybrids than for the inbreds which is consistent with greater water use by the hybrids. Stomatal resistance and xylem water potential were not significantly different among genotypes.
The Effect of N Fertilizer Source on Grain Yield, N Uptake, Soil pH, and Lime Requirement in No‐Till Corn1
Authors: Fox R. H. , Hoffman L. D. 
Published: July 2010

AbstractThe increasing use of no‐till crop production with urea based N fertilizers in the Northeast makes it imperative that we obtain a more quantitative understanding of both the magnitude of apparent NH3 losses from nonincorporated urea fertilizers in the field and of the factors that contribute to those losses. A 4‐year field study was conducted on a Murrill silt loam (Typic Hapludult) to compare the yields and N uptake by no‐till corn (Zea mays L.) receiving five rates of broadcast, unincorporated N (0 to 202 kg/ha) as NH4NO3, urea, urea‐NH4NO3 solution (UAN), or (NH4)2SO4. The effects of these sources on the soil pH of the 0 to 2.5 cm and 0 to 17 cm layers and on the lime requirement (LR) in the 0 to 17 cm layer were also measured. In 2 of the 4 years, either urea, UAN, or both produced signifcantly lower yields and N uptake than the non‐urea sources at the higher (101 and 202 kg/ha) N rates. Apparent N volatilization losses ranged from 0 to 35%. Comparing the results from this experiment with those from other field experiments reported in the literature where the effect of rainfall after N application on apparent N volatilization losses could be measured showed that the following observations applied to all: (1) there was insignificant NH3, volatilization loss from unincorporated urea fertilizers if at least 10 mm of rain fell within 48 hours after fertilizer application; (2) if 10 mm or more rain fell 3 days after the urea was applied, volatilization losses were slight (<10%); (3) if 3 to 5 mm of rain fell within 5 days, or 7 to 9 mm within 9 days, volatilization losses could be moderate (10 to 30%); and (4) if no rain fell within 6 days, the loss could be substantial (>30%).The pH in the surface 2.5 cm of soil in the plots receiving 202 kg/ha/year of N as NH4NO3 urea, or UAN for 5 years was approximately 5.7 or one unit below that in the check. In the plots receiving this rate of (NH4)2SO4, the soil pH in the 0 to 2.5 cm layer was 4.7. As expected, the 101 kg N/ha/year rate produced half was much lowering of pH as the 202 kg/ha rate.Lime requirement measurements in the surface 17 cm of soil receiving 202 kg N/ha/year for 5 years indicated that approximately 67% of the acidity theoretically produced in the nitrification of NH4+ remained to be neutralized with the less acidifying sources (NH4O3, urea, and UAN) and that approximately 100% of that from (NH4)2SO4 required neutralization.
Post‐dormancy Growth of Bermudagrass as Influenced by Low Temperatures and Selected Preemergence Herbicides1
Authors: Breuninger J. M. , Schmidt R. E. 
Published: July 2010

AbstractTurf managers in the upper south of the USA must often contend with slow recovery of bermudagrass (Cynodon sp.) following winter dormancy. It is, therefore, essential to identify factors which may contribute to reduced recovery from dormancy if bermudagrass is continued to be grown in this region. In this study, three experiments were conducted to determine the influence of the herbicides DCPA (dimethyl tetrachloroterephthalate), benefin (N‐butyl‐N‐ethyl‐α,α,α‐trifluoro‐2,6 dinitro‐ρ‐toluidine) and oxadiazon [2‐tert‐butyl‐4 (2,4‐dichloro‐5‐isopropoxyphenyl) ‐∆2−1,3,4‐oxadiazolin‐5‐one] on cold temperature tolerance and post‐dormancy growth of three bermudagrass cultivars, ‘Tifway,’ ‘Vamont,’ and ‘Midiron.’Two laboratory studies were designed to determine the influence of different rates of herbicides on the recovery of dormant bermudagrass that was subject to low temperatures. Herbicides were applied immediately before dormancy was initiated or prior to post‐dormancy growth. A field acclimated study was also conducted to ascertain the effects of herbicide application on post‐dormancy growth of two bermudagrass.From these experiments it was found that the preemergence herbicides DCPA, benefin, and oxadiazon reduce the cold temperature tolerance of Tifway bermudagrass. Post‐dormant root growth of Tifway bermudagrass was inhibited when new roots came into contact with a herbicide residue from an application prior to dormancy. The most severe root reduction occurred by applications of herbicides to dormant bermudagrass turf made after a laboratory freeze.Less phytotoxicity was obtained when low dosages of herbicides were applied to dormant Vamont bermudagrass that was not frozen. However, when herbicides were applied after Vamont bermudagrass was frozen, both low and high dosages produced similar results.Midiron and Vamont bermudagrass differed in their susceptibility to herbicide injury following freezing conditions. Vamont post‐dormancy recovery was decreased by the herbicides applied in this study, but Midiron was not.
Growth Response of Wheat to CO2 Enrichment and Different Levels of Mineral Nutrition1
Authors: Sionit Nasser , Mortensen D. A. , Strain B. R. , Hellmers H. 
Published: July 2010

AbstractMost previous studies on the influence of CO2 concentration on plant growth have investigated the effect of atmospheric CO2 enrichment alone. Little attention has been given to possible interactions between CO2 enrichment and nutrient supply. The objective of this study was to characterize the long‐term effects of atmospheric CO2 enrichment on growth components of wheat (Triticum aestivum L.) grown under different nutritional levels.Growth and yield responses of spring wheat (cv. GWO1809) to two (350 and 675 ppm) CO2 and four (full strength, 1/2, 1/8, or 1/16 strength Hoagland's solution No. 1) nutritional levels were measured in controlled environment chambers at day/night temperature of 26/20 C. Plants were grown from seed and were irrigated with respective nutrient solutions three times daily until maturity.Plants grown in a 675 ppm CO2 atmosphere produced more total dry matter at each nutrient level compared to those grown in 350 ppm CO2. The root:shoot ratio decreased with increased nutritional level in both CO2 concentrations. Total weight and number of seeds produced in high CO2 were greater than those produced in low CO2 under similar nutrition. In low CO2, seed weight and number increased with each increase in nutrient concentration up to the one‐half strength level and then decreased with full strength. In high CO2, however, increasing the nutritional level from one‐half to full strength did not decrease seed weight and number significantly. As the plants grew older, the increments of increase in total plant dry weight during harvest intervals were always greater in plants grown in 675 ppm CO2 than those grown in 350 ppm CO2.
Modeling Biomass Production of Sweet Sorghum1
Authors: Shih S. F. , Gascho G. J. , Rahi G. S. 
Published: July 2010

AbstractSweet sorghum [Sorghum bicolor (L.) Moench] is a leading contender in biomass production energy systems because of its high biomass yield, high percentage of easily fermentable sugars and combustible organics, tolerance to water stress, and low fertilizer requirements. However, scientific information on growth factors is limited and precludes establishing valid interrelationships for predicting biomass production. With that objective in mind, a field study on sweet sorghum was conducted to investigate the relationships among stalk length, leaf area index, and dry biomass. Cultivar Mer 71‐7 was planted using two row configurations of single rows on 71‐cm centers and double rows on 142 cm centers on Pahokee muck (Lithic Medisaprist). The spacing between double rows was 30 cm. Leaf area, stalk length, and dry leaf biomass were periodically monitored. Six equations involving leaf area were developed. The first equation estimated leaf area (A) from the length of leaf (L) and the maximum width of leaf (W), i.e., A = 0.741 LW. The second equation estimated leaf area from the length of leaf alone, i.e., A = 0.083 L2. The third equation estimated leaf area per stalk (Y) from stalk length (X), i.e., Y = Exp[X/(2.106 + 0.093X + 0.629X × 10‐4X2)]. The fourth equation showed the dry leaf biomass accumulation (DAR) as a function of time (T), i.e., DAR = 0.764 × 10‐3T0.481. The fifth equation predicted the leaf dry biomass (LDB) from DAR and leaf area index (LAI), i.e., LDB = DAR × LAI. The sixth equation estimated total dry biomass (TDB) from LDB and ratio of dry leaf biomass to total dry biomass (DBPL), i.e., TDB = LDB/DBPL. The relationships developed appeared to be useful for estimating sweet sorghum biomass. However, further testing is needed to evaluate the effects of diverse growing conditions and varieties and to determine the utility of the method in comparison to determining the mean plant weights and populations.
Leaflet Orientation in Water‐stressed Soybeans1
Authors: Meyer Wayne S. , Walker Sue 
Published: July 2010

AbstractTerminal leaflets of soybeans [Glycine max (L.) Merr.] were observed to become erect and then to invert during a period of soil drying. This study examined the interaction between this movement, abaxial and adaxial stomatal response, water potential, and surface reflectance of terminal leaflets as plant water status decreased. Observations were made on plants in a field with a Rhodic Paleustalf soil type and in which was located a weighing lysimeter.Terminal leaflets first assumed an erect orientation and then an inverted position as total plant available water decreased below 40%. With more severe water stress a greater proportion of leaflets were affected and lateral leaflets also become inverted. The onset of terminal leaflet inversion occurred over a range of leaf water potential values of −1,400 to −1,725 kPa. Inversion of the leaflets exposed the abaxial surface which was more reflective and which maintained a higher level of diffusive conductance under water stress conditions than did the adaxial surface. Leaflet reorientation in water−stressed soybeans may be a mechanism by which water loss is reduced while still maintaining some level of productivity.
Combination of Herbicides for Winter and Summer Weed Control in Turf1
Authors: Johnson B. J. 
Published: July 2010

AbstractIt is usually necessary to apply herbicides to control both winter and summer weeds in bermudagrass [Cynodon dactylon (L.) Pers. ‘Common’] turf. A study was conducted on a Cecil (Typic Hapludult) loam or sandy clay loam at Griffin, Ga. to determine whether combinations of preemergence type herbicides for summer weeds and postemergence type herbicides for winter weeds would control both type weeds as effectively as when each herbicide was applied singly.Tank mixture of paraquat (l,l′‐dimethyl‐4,4′‐bipyridinium ion) at 0.3 kg/ha with preemergence herbicide treatments generally controlled a higher percentage of winter annual broadleaf weeds than when paraquat was applied alone at the same rate. In contrast, glyphosate [N(phosphonomethyl)glycine] mixtures were less effective than glyphosate alone. Control of corn speedwell (Veronica arvensis L.) was significantly improved from tank mixture of 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] + mecoprop {2[(4‐chloro‐o‐tolyl)oxy]propionic acid} + dicamba (3,6‐dichloro‐o‐anisic acid) with preemergence treatments than with postemergence treatment alone. Bensulide [O‐O‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl)benzenesulfonamid] and prosulfalin {N‐[[4‐(dipropylamino)‐3,5‐dinitrophenyl]sulfonyl]‐S,S‐dimethylsulfilimine} controlled large crabgrass [Digitaria sanguinalis (L.) Scop.] as effectively when applied as tank mixtures with postemergence herbicide treatments as when applied alone. However, combination of DCPA (dimethyl tetrachloroterephthalate) with the same postemergence treatments reduced large crabgrass control in 1 or more years. Control of goosegrass [Eleusine indica (L.) Gaertn.] from tank mixtures of preemergence treatments with postemergence treatments was just as effective as with preemergence treatments alone.
Yield, Yield Components, and Nutrient Content of Corn Grain as Influenced by Post‐Silking Moisture Stress1
Authors: Harder H. J. , Carlson R. E. , Shaw R. H. 
Published: July 2010

AbstractSensitivity of corn (Zea mays L.) grain development to moisture stress is related to the physiological stage of development when stress occurs. For this reason the time when moisture stress occurs is important in determining final grain yield; hence, timing of precipitation or irrigation becomes an important economic factor in corn production. The primary objective of this work was to determine the effect of successive, repetitive moisture‐stress treatments on yield and yield components. To accomplish this goal, experiments were conducted in the movable rain shelter facility at Ames, Iowa, during the summers of 1976 and 1977. With this facility, different soil‐moisture conditions were imposed simultaneously with plants growing under similar conditions of atmospheric demand. Corn plants were grown in containers with 100 liters of a Nicollet loam soil (an Aquic Hapludoll, fine‐loamy mixed mesic). Single and multiple periods of moisture stress were imposed after silking in one, two, or three successive stress cycles to study their effect on grain yield and yield components (kernels/plant and mass/kernel). Successive respective stress treatments on the same plants were included to observe plant response to moisture stress after sink size (kernel number) was altered because of previous stress.Grain yield reductions of up to 33% depended primarily upon severity and duration of soil‐moisture stress. Additional stress cycles did not always cause an additive reduction in grain yield. Moisture stress that occurred within 2 weeks after silking reduced the number of kernels/plant by about 15% with little influence on final mass/kernel. Additional stress cycles had only minor effects on kernel number. Plants that were stressed shortly after silking and suffered reduction in kernels/plant had shorter, but uniformly filled ears, suggesting that stress‐inhibited development of kernels at the tip of the ear. Moisture stress influenced masskernel in a complex fashion. Decreases up to 20% were observed. The observed pattern for mass/kernel depended on the timing of stress in relation to silking date and previous moisture‐stress history of the plant. Moisture stress increased % N in the grain from 1.7% in controls to 1.8 and 1.9% in one and two repeated stress cycles, respectively, but did not significantly influence % P or % K in the grain at harvest.