bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axial Resistance to Water Flow of Intact Cotton Taproots
Authors: Yamauchi Akira , Taylor Howard M. , Upchurch Dan R. , McMichael Bobbie L. 
Published: July 2010

AbstractA knowledge of root hydraulic resistance is required for the application of water flow models of the plant‐soil system. An attempt was made to estimate axial resistance of intact cotton (Gossypium hirsutum L. cv. Tamcot CAMD‐E 107‐5A) taproots to water flow by direct and simultaneous measurement of water flow rate and of the gradient in xylem water potential. Fiscus's root psychrometer was modified and used for the measurement of xylem water potential. The measurements were made in rigidly controlled, constant temperature environments, and under conditions in which no water was available for the portion of the taproot where xylem water potential gradient was measured, but water was available distal to that portion. The water uptake rate was simultaneously measured while water was supplied at a constant head. Axial resistance to water flow along a cotton taproot of 70‐ to 120‐d‐old plants was on the order of 1 mg−1 water m−1 root s MPa, which is near the lower limit of published values for cotton and other species. Axial resistance was also calculated from the measured xylem vessel diameters based on the Poiseuille‐Hagen equation. Measured axial resistance values were ≈ 20 times those calculated using the Poiseuille‐Hagen equation. It required as long as 34 d for the water potential inside the psychrometer chamber to equilibrate with that of the root xylem. Drying the root substantially increased the radial resistance and thereby increased the time required for equilibration. Modifications to the described experimental apparatus and procedure will be required.
Biomass and Nitrogen Accumulation in Switchgrass: Effects of Soil and Environment
Authors: Stout William L. , Jung Gerald A. 
Published: July 2010

AbstractGrasslands are the basis of animal agriculture in the northeastern USA. Adapted warm‐season grasses make a valuable contribution to grassland production in this region, but knowledge of the interactive effects between soils and environment on their production is limited. Our objective was to examine and evaluate the interactive effects of soils and environment on biomass and N accumulation by switchgrass (Panicum virgatum L. cv. Cave‐n‐Rock), an adapted warm‐season grass. The study was conducted for 3 yr on four sites in central Pennsylvania selected to provide differences in soil water holding capacity and temperature regime. Switchgrass was treated with 0 and 84 kg N ha−1 as NH4NO3. Biweekly biomass samples were taken starting 15 June and continued until the grass reached heading stage, approximately 31 July. Biomass accumulation rates for this 31‐d period ranged from 157 to 211 kg ha−1 d−1. Soil N, N fertilization, and temperature controlled biomass accumulation rates. Total N uptake rates ranged from 1.49 to 2.63 kg ha−1 d−1 and were controlled by soil N levels and N fertilization. Fertilizer N recovery averaged about 40%, and was lowest where native soil N exceeded 2.0 g kg−1.
Nitrogen Dynamics in Irrigated Corn: Soil‐Plant Nitrogen and Atmospheric Ammonia Transport
Authors: Harper Lowry A. , Sharpe Ronald R. 
Published: July 2010

AbstractAmmonia transport in cropping systems can affect atmospheric pollution, soil‐plant N relationships, and crop N‐use efficiency. The purpose of this study was to evaluate the N dynamics of a corn (Zea mays L., Pioneer hybrid 3379) cropping system and determine the effect of NH3 transport and crop NH3 compensation point on N relations in the crop. Soil and plant N measurements were made during the growing season along with plant‐atmosphere NH3 transport using flux‐gradient micrometeorological techniques. The crop generally emitted NH3 throughout the season when the atmospheric NH3 concentrations were near background levels. During periods of high atmospheric NH3 concentrations, the crop absorbed significant amounts of NH3 from the atmosphere. Net seasonal NH3 transport was determined to be a small loss, based on the number of measurement periods throughout the growing season; however, N isotope studies in a nearby field estimated significant NH3 losses. Nitrogen isotope studies cannot account for the substitution of 14NH3 absorbed from the atmosphere for volatilized 15NH3. These results indicate that care must be taken when using N isotopes to evaluate N losses from cropping systems when plants are actively growing. Nitrous oxide flux was measured late in the cropping season, but showed small denitrification losses during the measurement period. The crop NH3 compensation point varied during the time of day and with respect to soil‐plant‐atmosphere influence. Net NH3 transport accounted for little of the N lost from this cropping system.
Forage Potential of Spring and Winter Cereal Mixtures in a Short‐Season Growing Area
Authors: Jedel Patricia E. , Salmon Donald F. 
Published: July 2010

AbstractCereal crops are often used in short‐season growing areas as annual forages for silage, greenfeed, or pasture. Field tests were conducted at Lacombe, AB, Canada, from 1989 to 1991 to determine the forage yield and quality of spring cereal monocrops of ‘Wapiti’ spring triticale ( ✕Triticosecale Rimpani Witt.) or ‘Johnston’ spring barley (Hordeum vulgare L.) and of binary mixtures of the spring cereals with ‘OAC Wintri’ winter triticale or ‘Musketeer’ winter rye (Secale cereale L.) grown at 1 × (260 seed m−2) and 1.5 × normal seeding rate. Dry matter (DM) yield and quality were determined for two simulated forage regimes: (i) a soft‐dough cut for silage, followed by fall clipping, and (ii) annual pasture with up to five clippings during the growing season. Yields of the spring cereal monocrops were 3.34 to 15.94 t ha−1 when harvested for silage, with fall clipping yields of 0.00 to 1.00 t ha−1. Yields for the mixtures were 2.88 to 14.64 t ha−1, with fall clipping yields of 0.05 to 2.39 t ha−1. For the annual pasture regime, initial clipping yields of spring cereal monocrops were 0.29 to 1.96 t ha−1; yields of the mixtures were 0.18 to 1.93 t ha−1. Monocrop yields declined over the growing season, while yields from the mixtures increased to midsummer and then declined (but less rapidly than for the monocrops). Under the annual pasture regime, quality of all treatments for the early clippings was similar, but by late summer and fall the mixtures had higher protein and lower acid‐detergent fiber concentrations than the spring cereal monocrops. The 1.5 × seeding rate resulted in higher DM yield when harvested for silage and for the initial clip when harvested for annual pasture. Spring‐winter cereal mixtures may extend productivity and high quality of annual pastures in short‐season growing areas.
Post Stratification Clarifies Treatment Effects on Pearl Millet Growth in the Sahel
Authors: Buerkert Andreas , Stern Roger D. , Marschner Horst 
Published: July 2010

AbstractSpatial variation in the growth of pearl millet [Pennisetum glaucum (L.) R. Br.] over short distances is a problem in field experiments in the Sahel, but the causes are still poorly understood. Data from a 3‐yr experiment with millet were used to compare four data types for their usefulness for reducing variation not related to treatment: (i) soil chemical data, (ii) residuals of the first year's yield data, (iii) a traditional fertility classification system, and (iv) plant vigor scores. The completely randomized experiment consisted of four factors combined to 48 treatments, replicated twice. There were three levels of millet crop residues (CR), two levels of broadcast P, and four genotypes; the fourth factor had two levels and varied over years. Whereas chemical analyses of the topsoil did not explain overall variation, residuals of plant scores used as covariates led to a reduction in residual variation of 32% for straw and 51% for grain yield in 1991. Most satisfactory, however, was the use of residuals of plant scores to classify plots into two strata of relatively low and high inherent soil productivity (a retrospective procedure called post stratification). In low‐productivity plots, a CR application of 2000 kg ha−1 (compared with 500 kg ha−1) increased millet straw yield by an average of 42% and grain yield by 48% for the first 2 yr. In contrast, under high productivity, yields were barely influenced by treatments. The application of P, however, was equally effective in both productivity strata. The results show that vigor scores can be useful to clarify treatment effects on millet growth. The different responses of crop residues and P in the two productivity strata also indicate that nonchemical parameters such as soil mechanical resistance may contribute to soil microvariability in the Sahel.
Populations of Foliage‐Inhabiting Arthropods on Soybean with Reduced Tillage and Herbicide Use
Authors: Buntin G. David , Hargrove William L. , McCracken Daniel V. 
Published: July 2010

AbstractModification of tillage and herbicide use patterns to reduce adverse environmental effects on soybean [Glycine max (L.) Merr.] production may impact arthropod populations and damage in soybean. The objectives of this field study were to examine the effect of reduced tillage and herbicide use on populations of foliage‐inhabiting phytophagous and beneficial arthropods and their damage in soybean. Tillage treatments of no‐tillage, chisel‐plow with disking, and moldboard plow with disking and herbicide regimes of high (preplant and postemergence control), reduced (postemergence control), and no herbicide use were established in a 2‐yr rotation of corn (Zea mays L.), winter wheat (Triticum aestivum L.), and soybean. Phytophagous and predatory arthropods were sampled from soybean foliage with the shake‐cloth technique throughout the season in 1988, 1990, and 1992. Tillage treatments did not consistently affect any arthropod groups except stink bugs (Pentatomidae), which were more abundant in no‐tillage than plow‐tillage treatments, and bigeyed bugs (Geocoris spp.), which were more abundant in both plow‐tillage treatments than in no‐tillage. Herbicide regime also had no consistent effect on abundance of any taxa. Additionally, tillage and herbicide regimes had little consistent effect on soybean lepidopteran defoliation and pod damage caused by the bean leaf beetle [Cerotoma trifurcata (Forster)] over the 3 yr. There were extensive stand losses due to rodent damage (cotton rat; Sigmodon hispidis Say & Ord) in the no‐tillage, no‐herbicide system in 1992, where crabgrass [Digitaria sanguinalis (L.) Scop.] was prevalent. These results suggest that tillage and herbicide use practices can be modified without greatly affecting arthropod populations and their damage in soybean. However, these results imply that the potential for managing arthropod populations by modified tillage and herbicide use is limited in soybean.
Maize Silage Utilization of Fertilizer and Soil Nitrogen on a Hill‐land Ultisol Relative to Tillage Method
Authors: Staley Thomas E. , Perry H. Douglas 
Published: July 2010

AbstractFew studies have compared N utilization by maize (Zea mays L.) under conventional tillage (CT) and no‐tillage (NT) in the Appalachian region. Silage production (TDM) and fertilizer N and soil N uptake, were investigated in a 3‐yr study on a Gilpin silt loam (fine‐loamy, mixed, mesic Typic Hapludult) in West Virginia previously cropped to pasture. 15N‐depleted N fertilizer was band‐applied, within‐row, at 0, 56, 112, and 224 kg N ha−1, 4 wk after planting. Tillage method did not affect silage production, N concentration or total N uptake at any N rate. Maximal silage production under NT (13.2 Mg ha−1) was calculated to require just 24 kg ha−1 more fertilizer N than under CT (12.6 Mg ha−1). Fertilizer N uptake (kg ha−1) was similarly unaffected by tillage method, with annual fertilizer N use efficiencies (% recovery) of 55, 54, and 49% under NT, and 57, 57, and 48% under CT, at application rates of 56, 112, and 224 kg ha−1, respectively. Similar percentages for cumulative fertilizer N use efficiencies, which account for any labeled N carried over from year to year, suggest that there was little residuum available to the crop, particularly at near‐optimal N rates. Soil N uptake decreased by 17% with N additions below (56 kg ha−1) or above (224 kg ha−1) the optimum, but was generally unaffected by tillage method. These similarities between NT and CT for maize silage production and N use, despite using a management system contrived to show differences, emphasize the importance of edaphic and climatological factors in predicting N responses under various tillage methods. Nonetheless, these results show that reasonably high levels of silage can be produced without excessive fertilizer N requirements ( ≈ 170 kg N ha−1) or losses (< 50%) when pastures are converted to NT maize.
Root Growth and Distribution are Affected by Corn‐Soybean Cropping Sequence
Authors: Nickel S. E. , Crookston R. Kent , Russelle Michael P. 
Published: July 2010

AbstractCorn (Zea mays L.) and soybean [Glycine max (L.) Merr.] yield better when grown in rotation than when grown in monoculture, even under high inputs. The explanation for this yield increase due to rotation is not yet known. The objective of this study was to evaluate the effect of cropping sequence on seasonal root development of corn and soybean. We hypothesized that there would be more roots on rotated crops than on crops held in a continuous monoculture. The research was conducted in 1991 and 1992 at the Univ. of Minnesota Southwest Experiment Station on a Webster clay loam (fine‐loamy, mixed, mesic Typic Haplaquoll). Destructive root sampling via soil cores was performed at the seedling and flowering stages of both crops. Nondestructive root monitoring was performed weekly and recorded on video cassette tapes via an agricultural research video camera inserted into minirhizotron tubes that had been placed into the soil beneath crop rows. Our hypothesis that there would be more roots on first‐year corn than continuous corn was generally supported. Minirhizotron monitoring suggested that corn grown in rotation had greater root length density than continuous corn, with the exception of the top 12.5 cm, where continuous corn had greater root length density early in the season. Soil cores confirmed 22% more seedling roots in the top 12.5 cm on continuous corn. Our hypothesis that there would be more roots on first‐year soybean than continuous soybean was generally not supported. Minirhizotron monitoring indicated that when there were differences, continuous soybean had more roots than rotated soybean, with the single exception of depths of 37.5 to 50 cm, where rotated soybean had more than twice as many roots at flowering in 1992. Root length density data obtained from soil cores also indicated that rotated soybean had approximately twice as many roots at depths of 36 and 48 cm at flowering. Growth and distribution of both corn and soybean roots were thus affected by cropping sequence. Fewer roots in continuous corn may have been the result of autotoxins from decomposing roots of the previous corn crop. We do not have an explanation for increased soybean roots under monoculture.
Establishment and Persistence of Legumes Interseeded into Switchgrass
Authors: Blanchet Kevin M. , George J. Ronald , Gettle Randall M. , Buxton Dwayne R. , Moore Kenneth J. 
Published: July 2010

AbstractLittle information is available for renovation of established switch‐grass (Panicum virgatum L.) with cool‐season forage legumes. Field experiments were conducted to determine seeding success, persistence, and impact on grass when 10 forage legumes and a legume mixture were no‐till interseeded into established ‘Cave‐in‐Rock’ switchgrass near Ames, IA. Legumes interseeded in early April 1991 and 1992 were biennial ‘Polara’ white‐flowered sweetclover (Melilotus alba Medik.) and ‘Madrid’ yellow‐flowered sweetclover (‘Melilotus officinalis’ Lam.), ‘Norcen’ and ‘Fergus’ birdsfoot trefoil (Lotus corniculatus L.), ‘Apollo Supreme’ and ‘Alfagraze’ alfalfa (‘Medicago saliva’ L.), Mammoth and ‘Redland II’ red clover (Trifolium pratense L.), ‘Emerald’ crownvetch (Coronilla varia L.), common hairy vetch (Vicia villosa Roth.), and a 50:50 mixture of Norcen trefoil and medium red clover. Legume renovation was compared with grass fertilized with N at 0, 60, 120, and 240 kg ha−1. Excellent legume establishment was observed in June, about 2.5 mo after interseedings, with mean legume plant density of 195 and 163 plants m−2 for 1991 and 1992 seedings, respectively. Both alfalfa cultivars and hairy vetch had highest percentage establishment. Average legume persistence to June of the second year was nearly 50% for 1991 and 30% for 1992 seedings (less in 1992 because of greater winter losses). Grass stem density during the establishment year was not affected by legume renovation. Decline in grass stems during the second year was greatest for trefoil and the trefoil‐red clover mixture, and intermediate for alfalfa and red clover, with minimal to no effect for the sweetclovers, crownvetch, and hairy vetch. Hence, legumes can be successfully established into switchgrass and can be maintained into the second year
Ratoon Cropping Forage Sorghum for Silage: Yield, Fermentation, and Nutrition
Authors: McCormick M. E. , Morris D. R. , Ackerson B. A. , Blouin D. C. 
Published: July 2010

AbstractTwo field experiments were conducted on Lexington silt loam soil (fine‐silty, mixed, thermic Typic Paleudalf) to identify a harvest regime that would improve the nutritive value of ensiled whole‐plant sorghum [Sorghum bicolor (L.) Moench] while maintaining silage yield. In a 1‐yr preliminary study, first‐cut sorghum was harvested at mid‐vegetative, late‐vegetative, boot, bloom, and hard‐dough stages of maturity. Regrowth was harvested in late August. In a 2‐yr experiment, yield, ensiling losses, intake, and in vivo apparent digestibility of vegetative sorghum (initial and ratoon cute wilted 24 h) were compared with direct cut hard‐dough‐stage sorghum. Forages were stored in 1.8‐Mg‐capacity (fresh wt.) experimental silos and, upon opening, were fed to lambs (Ovis aries}. Results from the preliminary experiment indicated that dry matter (DM) yield of first‐cut sorghum was greatest at the hard‐dough stage; however, nutritional value was greatest for the mid‐vegetative stage. Maximum yield for the combined harvests was obtained when first harvest was made at boot stage. The 2‐yr experiment average DM yields were 7.3 Mg ha−1 for combined initial (mid‐vegetative stage) and ratoon crops, compared with 6.7 Mg ha−1 for the single hard‐dough‐stage harvest. Ensiling fosses did not differ with harvest regime. Vegetative sorghum was more digestible than sorghum harvested at the hard‐dough stage (670 vs. 570 g kg−1). These studies suggest that sorghum harvested twice per season (with wilting) will produce a higher quality silage than a single hard‐dough stage cutting, without yield reduction
Dry Matter and Seed Yield of Mediterranean Annual Legume Species
Authors: Martiniello Pasquale , Ciola Antonio 
Published: July 2010

AbstractKnowledge of the effects of seeding rate, irrigation, and forage harvest management on annual legume crops is essential for their proper agronomical exploitation. Cultivars and ecotypes of berseem clover (Trifolium alexandrinum L.), common vetch (Vicia sativa L.), and fieldbean (Vicia faba L.) were compared at two seeding rates, with and without irrigation, and under two harvest managements. These experiments were conducted in Foggia (southern Italy) during 1990 and 1991. Irrigation increased and stabilized forage and seed production reducing the consequences of erratic rainfall. Mean dry matter and seed yield increases due to irrigation were, respectively: 26 and 14% in common vetch, 25 and 9% in field‐bean, and 24 and 28% in berseem clover. Berseem clover showed an increase of 48% in seed yield with forage harvest management under irrigation. Seeding rate interacted mainly with irrigation treatment and length of vegetative period. The high seeding rate under irrigation in common vetch and field‐bean increased forage production more than seed yield. The herbage and seed yield components that responded to the high seeding rate under irrigation were plant height, stems per square meter for all legumes, pods per stem, and seeds per pod for field‐bean and common vetch, and heads per stem and seeds per head for berseem. Adapted varieties and ecotypes identified within each species represent genotypes with superior genetic potential for dry matter production and seed yield under a Mediterranean environment.
Calcium‐Ammonium Effects on Growth and Yield of Small Grains
Authors: Fenn L. B. , Hasanein B. , Burks C. M. 
Published: July 2010

AbstractCalcium (Ca++) is known to stimulate potassium (K+) and ammonium (NH+4) absorption rates by plants. Increased NH+4 absorption stimulates plant growth and development. However, little is known about the effect of Ca++ with NH+4 on small‐grain crops. The objective of this research was to examine the effect of Ca++/NH+4 on growth and development of wheat (Triticum aestivum L.), oat (Avena sativa L.), and barley (Hordeum vulgare L.). Treatments consisted of growing small grains using complete nutrient solutions with a molar ratio of 0, 0.30, 0.60, 1.20, and 1.80 Ca++/NH+4, and a check with NO‐3‐N. Plants were grown in the greenhouse to seedling (30 d), intermediate (elongating, 60 d), and mature (booting, 90 d) growth stages on a NO‐3 nutrient solution and then treated for 7 d with the Ca++/NH+4 fertilizer solutions. One set of plants was fertilized solely with the Ca++/NH+4 solution and another with a NO‐3 fertilizer solution. The addition of Ca++ with NH+4 to small grains resulted in increased N absorption, grain yield, tiller formation, dry matter, and grain weight per unit of plant dry matter, but the extent varied with the crop. Calcium apparently caused a redirection of foliar metabolites to grains. Short‐term treatments with Ca++/NH+4 at different growth stages showed the least results at the seedling stage, whereas maximum results were obtained at the intermediate growth stage (initiation of jointing) and good stimulation of plant growth and tillering at the mature (booting) stage. Calcium increased NH+4 absorption, leading to increased tillering, increased weight per head of grain produced, and consequently higher grain yields. Calcium added with NH+4‐N increases plant N use efficiency by more rapid absorption, greater rates of tillering, greater metabolite deposition in seeds, and possibly increases in photosynthesis.