bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of Cool‐Season Perennial Grasses in Pure Stands and in Mixtures with Legumes1
Authors: Barnett F. L. , Posler G. L. 
Published: July 2010

AbstractClarification of relationships among species in mixed stands is essential to enlightened management of forage mixtures. During 1976–1979, we evaluated several grass‐legume mixtures in a field study in eastern Kansas. Grasses were: commercial smooth brome, Bromus inermis Leyss.; ‘Regar’ Turkish brome, B. biebersteinii Roem. &Schult.; ‘Kentucky 31’ tall fescue, Festuca arundinacea Scbreb.; and ‘Ioreed’ reed canarygrass, Phalaris arundinacea L. Legumes were: ‘Kanza’ alfalfa, Medicago sativa L.; ‘Kenstar’ red clover, Trifolium pratense L.; ‘Dawn’ birdsfoot trefoil, Lotus corniculatus L.; and ‘Emerald’ crownvetch, Coronilla varia L. Each grass was grown in a two‐species mixture with each legume, and in a pure stand with 0 and 90 kg N ha‐1 as NH4NO3. Mixtures were obtained by alternating all‐grass and all‐legume drill rows. Legumes were grown in pure stands in an adjacent planting. Both plantings were on a Woodson silt loam of the fine, mixed, thermic family in the Abruptic Argiaquolls subgroup of the Mollisols. Dry matter (DM) yields were obtained from all plots. Proportion of grass in mixtures was determined from hand‐harvested samples. Dry matter yield of the grass component of each mixture was computed as the product of the DM yield of the whole stand and the proportion of grass in the mixture. Crude protein (CP) contents of whole stands and grass components of mixtures were computed as 6.25 times N. Although comparisons varied across years, mixtures averaged as much grass DM (3.21 Mg ha‐1) as unfertilized all‐grass stands (3.07 Mg ha‐1) during the 4‐year period. Crude‐protein contents of grass components of mixtures consistently ranked above those of unfertilized all‐grass stands; differences usually were significant (P < 0.05) but varied in magnitude with year and type of stand. Legumes differed significantly (P < 0.05) every year in DM yield and every year except 1979 in CP content. Over the 4‐year period, however, no legume was clearly superior in either variable.
Nitrogen Accumulation Rates of Irrigated Maize
Authors: Russelle M. P. , Hauck R. D. , Olson R. A. 
Published: July 2010

AbstractImproved fertilizer nitrogen (N) use efficiency in irrigated maize (Zea mays L.) often results from delaying application of moderate N rates until the crop is rapidly growing. The objective of this experiment was to determine how N application time, N rate, and planting date influenced the pattern of N and fertilizer−derived N (FN) accumulation in irrigated maize grown on a deep, productive silty clay loam soil (Typic Argiudoll, fine, montmorillonitic, mesic). A factorial combination of early and late planting, N application at planting, or at the 4−, 8− or 16−leaf growth stage, and two N rates (90 and 180 kg N ha−1 as 15N−depleted ammonium sulfate) were applied to the same plots in 1979–1980. Above−ground plant samples were taken at the 8−leaf, l2−leaf, silking, soft dough, and physiological maturity stages of growth. Average net rates of N and FN accumulation were calculated using a temperature index as the divisor. Rates of N and FN accumulation per plant were greatest between the 12−leaf and silking growth stages in 1979, except when N application was made at the 16−leaf stage where maximum accumulation rates occurred during early grain fill. Effects of N application time on N accumulation rates were more pronounced in 1980 and followed patterns similar to those in 1979. Substantial amounts of residual FN from 1979 accumulated in above−ground tissue in 1980. Residual FN uptake was apparently greater, in comparison to newly applied FN, in the heavily−fertilized or late−planted crop. Time of maximum N accumulation was delayed as time of N application was delayed. Grain yield was reduced by early N deprivation only when active N uptake ceased during early grain fill. Excessive N application minimized the effect of application time on final grain FN content. Delayed planting reduced FN recovery at both levels of N fertilization. Relative recovery of FN in maize grain was maximized by applying the low N rate late in vegetative growth, irrespective of planting date.
Competition of Jimsonweed with Soybean1
Authors: Kirkpatrick B. L. , Wax L. M. , Stoller E. W. 
Published: July 2010

AbstractJimsonweed (Datura stramonium L.) is a broadleaf weed that has become increasingly severe in Midwest soybean (Glycine max (L.) Merr.) fields (9, 14). Knowledge of the competitive effects of this weed with soybean would be helpful in developing production practices to minimize losses. Our objectives were to determine the response of soybean (cv. Wells) stand and seed yield to (a) various jimsonweed densities, (b) different emergence dates of jimsonweed, and (c) various durations of jimsonweed competition and to compare the effectiveness of bentazon [3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4(3H)‐one 2,2‐dioxide] in controlling jimsonweed to that of hand weeding. Greater densities of jimsonweed resulted in greater losses in soybean yields. Jimsonweed at a low density of 0.3 plants m−1 of row reduced yield by as much as 8%, while jimsonweed at a higher density of 1.6 plants m−1 of row reduced yield by as much as 24%. Increased delay of jimsonweed emergence following soybean emergence markedly reduced soybean yield losses. Jimsonweed at a density of 1.6 plants m−1 of row emerging 2 and 4 weeks after soybean emergence decreased yields by 7 and 3%, respectively, compared to a 23% reduction in yield when jimsonweed emerged with soybean. As duration of competition increased, yields decreased. At a density of 1.6 plants m−1 of row jimsonweed competing with soybean for 2 and 4 weeks reduced yields up to 7 and 14%, respectively. Jimsonweed competing with soybean for the full season reduced yield up to 41%. Soybean stand was not affected by jimsonweed density, time of emergence, or duration of competition. Bentazon was just as effective as hand removal for terminating jimsonweed competition at all application dates.
Effects of Sodium Chloride on Cynodon Turfgrasses1
Authors: Dudeck A. E. , Singh S. , Giordano C. E. , Nell T. A. , McConnell D. B. 
Published: July 2010

AbstractIncreased need for salt tolerant turfgrasses continues due to increased restrictions on water resources and to salt water intrusion into ground water. This is especially critical along coastal areas. Bermudagrass (Cynodon spp.) cultivars are widely used throughout the South on golf courses, home lawns, and sports turf facilities. Information on tolerance of warm‐season turfgrass cultivars to salinity is limited. The purpose of these studies was to document the glasshouse response of eight bermudagrass cultivars to solution cultures differentially salinized with NaCl. Salt was added to a basic nutrient solution to provide five initial salinity levels ranging from 2.7 to 9.9 dS m−1, but no cultivar differences were found in duplicate studies. Overall, top growth decreased 22%, but root growth increased 270% at the highest salt level. When salt levels ranged from 2.4 to 32.5 dS m−1 in a third study, cultivars differed in their response. ‘Tifdwarf’ and ‘Tifgreen’ were most tolerant while ‘common’ and ‘Ormond’ were most sensitive. Based on regression analyses within cultivars, Na increased and K decreased while total Na plus K in top growth was unaffected by salt concentration. Tissue levels of total Na plus K differed among cultivars.
Emergence and Yield of Fungicide‐Treated Soybean Seed Differing in Quality1
Authors: Wall M. T. , McGee D. C. , Burris J. S. 
Published: July 2010

AbstractCurrent recommendations that soybean (Glycine max L. Merr.) seeds be treated with fungicides if they are of poor quality or to be planted in cool, wet soils, are too vague for the grower to be sure when treatment is warranted in the upper Midwest. This paper evaluates the effects of fungicide treatments on seeds with different quality characteristics under more precisely‐defined soil conditions than in previously reported studies. Seedlots of ‘Cumberland’, ‘Wells’, and ‘Williams’ with inferior quality due to age, damage, small size, or infection by Phomopsis spp. were treated with captan {N(trichloromethyl)‐thio]‐4 cyclohexene‐1,2‐dicarboximide}, carboxin‐thiram (5,6‐dihydro‐2‐methyl‐1, 4 oxathiin‐3‐carboxanilide, 17%; tetramethylthiuram disulfide, 17%), metalaxylN‐(2,6‐dimethylphenyl)‐N‐(methoxyacetyl) alanine methyl ester) or untreated. These were tested for emergence and yield in the field on two soil types [a poorly drained Webster silty clay loam (fine‐loamy, mixed, mesic, Typic Haplaquolls), and a well drained Clarion loam (fine‐loamy, mixed, mesic, Typic Hapludolls)] at three different planting times in both 1980 and 1981. Captan and carboxin‐thiram seed treatments were equally effective in increasing emergence in the laboratory and field of soybean seedlots with more than 15% Phomopsis spp. infection, but metalaxyl did not. No seed treatment consistently improved field emergence of seeds with reduced quality because of mechanical damage, age, or size. There were no obvious differences in fungicide performance in relation to planting dates or soil types. Increased yield in response to fungicide seed treatment was detected only in the 50% Phomopsis‐infected seedlot. We conclude that fungicide seed treatment cannot be justified on seeds of low quality for reasons other than disease under most of the soil conditions likely to occur in the upper Midwest. These results suggest that performance of seedlots with Phomopsis spp. infection exceeding 15% will be improved by fungicide seed treatment.
Aluminum Toxicity and DNA Synthesis in Wheat Roots1
Authors: Wallace S. U. , Anderson I. C. 
Published: July 2010

AbstractAluminum toxicity is a deterrant to the growth of plants in acid soil. Little is known of the initial site or sites of Al injury in plant roots nor of the sequence of events that characterize Al toxicity. The objective of this study was to document some effects of short‐term exposure to Al in two wheat (Triticum aestivumL.) cultivars, Eagle and Atlas 66. Root elongation in Eagle was much more susceptible to concentrations of 0.02 to 1.85 mMAl than was root elongation in Atlas 66. A 2‐h exposure to 0.19 mMAl drastically inhibited root elongation in Eagle, whereas a 48‐h treatment with 0.19 mMAl had little effect on root elongation in Atlas 66. Exposures of Eagle seedlings to 0.19 mMAl for 4 h caused a 32% inhibition in subsequent incorporation of 3H‐thymidine into DNA, with the degree of inhibition increasing with duration of exposure to Al. In Atlas 66, there was a 10% reduction in incorporation of radioactivity into the DNA fraction for all the Al pretreatments, ranging from 2 to 48 h. Exposure of Eagle roots to AI for 2 h showed this same 10% reduction in incorporation of radioactivity into DNA. For both cultivars, there usually was a 10 to 20% decrease in 3H‐thymidine uptake by whole roots after 0.19 mMAl pretreatment periods of 2 to 12 h as compared with control plants not receiving AI. The extent of inhibition was fairly constant and was not correlated with duration of Al pretreatment for either cultivar. There was a similar depression of 3H‐thymidine uptake in root tips of Eagle after 4 to 12 h of Al pretreatment. The reduction of 3H‐thymidine uptake in both cultivars resembled the depression of 3H‐thymidine incorporation into DNA in Atlas 66 but not in Eagle. This work suggests that Al has two effects on susceptible cultivars: a rapid inhibition of root elongation followed by an inhibition of DNA synthesis. Another effect of AI on both the tolerant and the susceptible cultivar, that of depression of 3H‐thymidine uptake, also was seen.
Turfgrass Evapotranspiration. 11. Responses to Deficit Irrigation1
Authors: Feldhake C. M. , Danielson R. E. , Butler J. D. 
Published: July 2010

abstractIn the arid west, deficit irrigation has contributed significantly to efficient utilization of water resources. In order to understand possible benefits of deficit irrigation in turfgrass management, yield must be defined in terms of gain from water expended. Turfgrass quality influences the aesthetic appeal and physical comfort of urban environments. The effect of deficit irrigation on turfgrass quality was studied using small lysimeters where root systems were confined and evapotranspiration (ET) was limited to the amount of irrigation. In most cases there was a sharp change in slope of the quality vs. ET relationship for turfgrass. Kentucky bluegrass (Poa pratensis L. var. 'Merion') decreased about 10% in quality with an irrigation schedule providing up to a 279% ET deficit. Larger deficits resulted in greater relative decreases in quality. When ET was maintained at greater than 30% deficits, the quality rating of Kentucky bluegrass was lower if mowed at 2 cm than when mowed at 5 cm. When N fertility was low, maximum ET and maximum quality were decreased, but the response of quality to irrigation deficits greater than 27% was similar. The response of tall fescue (Festuca arundinaceaSchreb. var. 'Rebel') to deficit irrigation was similar to that of Kentucky bluegrass. Buffalograss [Buchloe dutyloides(Nutt.) Engem.], however, responded with notable differences. Decreasing ET also had an effect on microclimate. Turfgrass canopy temperature increased 1.7°C for each 10% decrease in irrigation up to 70% decrease suggesting that, during summer months, if irrigation is limited, the effect on urban climate may become a concern.
Water Table Depth Interaction with Nitrogen Rates on Subirrigated Corn1
Authors: Woodruff J. R. , Ligon J. T. , Smith B. R. 
Published: July 2010

AbstractWater table control for both drainage and subirrigation holds potential benefit to crop production on many soils with imperfect drainage. Losses of soil NO‐3‐N may occur through denitrification under partial anaerobic conditions such as would be encountered near a water table. In this 3‐year field study, four N rates were superimposed over three water table depths to test the effect of water table depth on corn (Zea maysL.) response to N in a Chewacla silt loam (fine‐loamy, mixed, thermic Fluvaquentic Dystrochrepts). Water table depths were 0.35,0.70, and 1.00 m and N rates were 0,112,224, and 336 kg ha−1. The effects of N fertilization depended on the water table depth. For the 3‐year means, quadratic regressions described the relationship between N rate and ear yield or leaf N for each water table depth except 1.00 m ear yield for which no response to N fertilizer was obtained. The N rate required for maximum ear yield or leaf N increased with decreasing water table depth. There were positive linear regressions of stover yields and soil NO‐3‐N on N rate for each water table depth. With the 1.00 m water table, the N response slope was less for stover yield and greater for soil NO‐3‐N than over the shallower water table depths. The lowest ear and stover yields were associated with deficient leaf N concentrations (< 27.5 g kg−1) where no N was added over the 0.35 and 0.70 m water table depths. The results suggest that soils with water tables within 0.70 m depth require more N fertilization to reach maximum corn yields than soils with deeper water tables.
Forage Production and Weed Control in a Double‐Cropping Program1
Authors: Okoli Paul S. O. , Drolsom P. N. , Scholl J. M. 
Published: July 2010

AbstractTo make more intensive use of increasingly‐scarce and expensive farmland, farmers in the North‐Central region of the United States are developing considerable interest in double‐cropping systems involving feed production. Therefore, forage production and quality were evaluated in double‐cropping systems involving corn (Zea maysL.), soybeans [Glycine max(L.) Merr.], and grain sorghum [Sorghum bicolor(L.) Moench] no‐till planted following conventionally‐planted spring oats (Avena sativaL.) for forage. The 2‐year field studies were undertaken on two soil types, Plano silt loam [fine‐silty, mixed, mesic Typic Argiudoll (Exp. I)] and Fayette silt loam [fine‐silty, mixed, mesic Typic Hapludalf (Exp. II)] at two separate locations in Wisconsin. The effects of irrigation and weed control practices (chemical and cultural) on the second crops were investigated. The 2‐year average forage yields of corn, soybeans, and grain sorghum were 5820, 2660, and 3890 kg ha−1, respectively.Cultivation generally resulted in better weed control than herbicides. Irrigation increased forage yields of corn, soybeans, and grain sorghum by 31, 38, and 32%, respectively. Soybeans produced the highest crude protein (CP) ha−1but the lowest quantity of digestible dry matter (DM), estimated by the in vitro dry matter digestibility (IVDMD) technique. Corn produced the highest amount of digestible DM ha−1but had the lowest CP percentage. Grain sorghum had thelowest IVDMD and produced the lowest CP ha−1. Based on 2‐year averages, the oats‐corn double‐cropping system produced the most forage, CP and digestible DM. Double‐cropping yields show considerable promise, when compared with present yields under a one crop system.
Nitrogen Fertility Effects on Accumulation, Remobilization, and Partitioning of N and Dry Matter in Corn Genotypes Differing in Prolificacy1
Authors: Anderson E. L. , Kamprath E. J. , Moll R. H. 
Published: July 2010

AbstractResults from previous studies have shown that more prolific corn (Zea maysL.) genotypes produce more grain per plant than less prolific genotypes. The objectives of this field study were to determine the effect of N fertility on dry matter (DM) and N accumulation, partitioning, and remobilization in genotypes which differ in prolificacy (ear number per plant). Two N rates were used, 56 and 224 kg N ha−1on a Typic Plinthic Paleudult. Eight genotypes were grown in 1978 and three in 1979. Leaves, stalks, and ears were sampled at various times during grain fill and N content was determined. Leaf dry weight did not change during grain fill at either of the N rates. Stalk dry weight increased initially during grain fill and then decreased at the low N rate, for all genotypes, but at the high N rate, only the nonprolific genotype showed the initial increase. The rate of increase in ear dry weight was constant throughout the grainfilling period at low N, but decreased after 30 days at high N. Leaf N decreased linearly during grain fill at both N rates. The decrease in stalk N was curvilinear at both N rates with most of the decrease occurring in the first 30 days after silking. Ear N accumulated at a linear rate for the first 30 days during grain fill and then proceeded at a slower rate. Grain yield per plant was associated with the number of ears per plant. Increasing the N rate tended to increase the number of ears per plant of the more prolific genotypes. Genotypes with a greater average ear number were more efficient in using accumulated N in producing grain and partitioned more of the total plant N and DM to grain production.
Stability of Soybean Harvest Index1
Authors: Spaeth S. C. , Randall H. C. , Sinclair T. R. , Vendeland J. S. 
Published: July 2010

AbstractPrevious work had indicated that the harvest index within cultivars of soybeans [Glycine max(L.) Merr.] might be fairly stable. Such stability of harvest index would greatly simplify the conceptualization of the influence of seed growth processes on yield. In the studies reported here harvest index of field‐grown soybean plants was measured in response to four types of environmental influence: interplant competition, extended photoperiod, timing of drought stress, and degrees of drought stress (line source irrigation). The experiments included both indeterminate and determinate cultivars, and included both a northern (Ithaca, N.Y.) and southern location (Gainesville, Fla). These experimental conditions resulted in considerable variability in plant sizes within a cultivar but the harvest index (ratio of seed mass to mass of mature plant without fallen leaves and petioles) was stable. Total masses of individual mature ‘Chippewa 64’ and ‘Bragg’ plants varied substantially in response to interplant competition, but harvest index was essentially constant (0.54 and 0.50 for Chippewa 64 and Bragg, respectively) across most of the range of plant sizes. Harvest index of smaller plants was less than for larger plants, but these smaller plants have little influence on total crop yield and harvest index. Extending the photoperiod to 14.5 h throughout the life cycle of six cultivars increasingly delayed ontogenic events as the distance from the photoperiod lamps decreased. However, no influence on harvest index was observed except at the position nearest the lamps where the standard errors of the harvest indices were increased. Harvest index did not respond to differences in the timing of severe drought stress. When rain was withheld from ‘Wilkin’ plants during vegetative growth, flowering, or seed setting, harvest index of individual plants was essentially 0.60. Only those plants stressed late in pod filling had lower harvest index and increased variability in harvest index. Seed yields (Chippewa 64, Wilkin, and ‘Evans’ for three planting dates) decreased substantially as degree of drought stress, induced by increasing distance from a line source irrigation system, increased yet, harvest index changed negligibly with distance from the line source. Thus, we conclude that harvest index is a conservative characteristic within each soybean cultivar.
A Trend Toward a Longer Grain‐Filling Period for Corn: A Case Study in Indiana1
Authors: McGarrahan J. P. , Dale R. F. 
Published: July 2010

AbstractIn assessing the effect of weather on crop growth and yield it is necessary to consider the stage of crop development. In most states since 1951 the USDA Statistical Reporting Service (SRS) has collected and summarized reports of crop progress during each season. For corn (Zea mays L.) and crop reporting districts (CRD) in Indiana, dates by which 50% of the corn acreage had been planted, silked, and matured were used to examine the trends in length of the corn vegetative and grain‐filling periods, measured in both days and thermal units from 1951 to 1980. It was found that there has been little change in the length of the period from planting to silking, but that the period from silking to maturity has increased from less than 50 days before 1961 to near 60 days in 1980. Although a climatic cooling trend may have contributed to this longer period of grain filling, the modified (10 to 30°C cutoff base) growing degree days required during the corn grain−filling period (silking to maturity) also increased, from less than 550 before 1961 to near 700 in 1980.