bluuebunny/crossref_metadata_2025_split huggingface dataset:
Canopy Management Influences on Cool‐Season Grass Quality and Simulated Livestock Performance
Authors: Turner Kenneth E. , Belesky David P. , Fedders James M. , Rayburn Edward B. 
Published: July 2010

AbstractInadequate energy intake across the grazing season can be a major limitation to performance of grazing ruminants. A small‐plot experiment was conducted to determine the effect of repeated defoliation, based on canopy height and on the quantity and quality of tall fescue × perennial ryegrass (Festuca arundinacea Schreb. × Lolium perenne L.) hybrid, orchardgrass (Dactylis glomerata L.), and prairie grass (Bromus catharticus M. Vahl) in the Central Appalachian Region of the USA. Energy determined from herbage quality data was used to predict growing steer performance. Early and repeated defoliation (T50, 20‐cm canopy cut to 10‐cm residue; S50, 10‐cm canopy cut to 5‐cm residue; and T75, 20‐cm canopy cut to 5‐cm residue) of the grasses resulted in greater herbage crude protein (CP) (202, 226, and 189 g kg−1, respectively) and lower neutral detergent fiber (NDF) concentrations (591, 572, and 596 kg−1, respectively) compared with the hay management (hay harvested at early seed head emergence followed by T75 management; 152 g CP kg−1 and 620 g NDF kg−1). Cumulative metabolizable energy yield on a 1000‐ha basis tended to be highest for hay (62 138 MJ ha−1) and T75 (49 678 MJ ha−1), compared with S50 (40 373 MJ ha−1) and T50 (28 457 MJ ha−1) simply because of greater herbage mass. Greatest average daily gain was predicted when 250‐kg steers grazed T50 (0.81 kg d−1) compared with S50 (0.70 kg d−1) and T75 ( 0.71 kg d−1). Total number of grazing days per hectare was lowest for T50 (431 d), compared with S50 (580 d) and T75 (690 d). Total annual gain was greater for T75 (690 kg liveweight ha−1) management than for S50 (580 kg ha−1) or T50 (436 kg ha−1). Using herbage earlier in spring before maturation may compromise total herbage productivity, but should sustain a greater number of grazing days and livestock productivity for a given land area.
Yield Rankings for Soybean Cultivars Grown in Narrow and Wide Rows with Late Planting Dates
Authors: Board James E. , Zhang Wei , Harville Bobby G. 
Published: July 2010

AbstractCultivar selection is a major problem for late‐planted soybean [Glycine max (L.) Merr.] in the southeastern USA. Cultivar yield rankings differ between optimal and late planting dates. Thus, recommendations for late plantings are based on statewide cultivar trials at late planting dates. Because such trials are large and expensive, high‐yielding cultivars in late plantings could be more rapidly and efficiently selected through identifying morphological and developmental parameters associated with cultivar yield performance. Furthermore, consistency of yield rankings between narrow‐ and wide‐row culture within a late planting is not known. Our objectives were to (i) determine if row spacing significantly affects cultivar yield rankings at a late planting date and (ii) identify yield components, growth dynamic factors, and phenological characteristics associated with cultivar yield differences at a late planting date. Twelve commercial soybean cultivars were planted in 91‐ and 50‐cm row spacings during 1992 and 1993 on a Commerce silt loam (fine‐silty, mixed, nonacid, thermic Aerie Fluvaquents) near Baton Rouge, LA (30°N lat). No significant cultivar × row spacing interaction for yield occurred. Yield rankings for the 12 cultivars were similar between row spacings (r2 = 0.95, P < 0.0001). Cultivar yield differences were attributed largely to differences in pod number (r2 = 0.35, P < 0.0001), rather than seed per pod (r2 = ‐0.07, P < 0.0001) or seed size (NS). Among all parameters, total dry matter at R5 was most highly correlated with yield (r2 = 0.55 to 0.62, P < 0.0001) across different row spacings or within the same row spacing. In conclusion, total dry matter at R5 and other parameters associated with yield were identified, parameters that can be used to develop regression equations for predicting cultivar yield performance in late plantings.
Design, Construction, and Installation of an Intact Soil Core Lysimeter
Authors: Moyer Jeffrey W. , Saporito Louis S. , Janke Rhonda R. 
Published: July 2010

AbstractAn intact soil core lysimeter with its insertion device and process was developed to facilitate the collection of leachate and soil water samples from a series of field plots in eastern Pennsylvania. This design was developed to minimize disturbance of the soil within and around the lysimeter. The lysimeter was constructed of 76.2‐cm‐diam. steel well casing with a 7.9‐mm wall thickness. The casings were cut to lengths of 1.15 and 0.75 m and were inserted by means of direct downward force to a depth of 1 m. An access hole 38 cm in diameter by 161 cm deep was then augered next to the inserted casing for the installation of a collection device beneath and beside the cylinder. The soil‐filled cylinder was removed and set on a prefabricated base and welded in place. The prefabricated base had drain holes and a fitting for attachment of the collection device. The collection unit was attached and the entire lysimeter was reinserted into the cavity. Leachate caught in the collection device was removed by. pumping through attached surface tubes alongside the cylinder. This design has proved to be efficient and cost‐effective. The insertion method kept soil compaction to a minimum while maintaining a watertight seal between the casing and soil core.
Growth Dynamics during the Vegetative Period Affects Yield of Narrow‐Row, Late‐Planted Soybean
Authors: Board James E. , Harville Bobby G. 
Published: July 2010

AbstractNarrow‐row culture is recommended for increasing soybean [Glycine max (L.) Merr.] yield at late plantings in the southeastern USA. Increased pod number resulting from greater light interception (LI) and crop growth rate (CGR) during the early reproductive period [first flowering to seed initiation (R1 to R5)] is mainly responsible for narrow‐row yield increases. However, little is known about rowspacing effects on Ll, CGR, and other growth dynamic parameters during the vegetative period [emergence (E) to R1] and how these parameters affect yield. Our objectives were to determine when LI and CGR differences in narrow vs. wide rows appear during E to R1, to determine if these differences contribute to narrow‐row effects on CGR(R1 to R5), and to determine the roles of leaf area index (LAI) and light interception efficiency (LIE = LI/LAI) in causing narrow‐row LI increases during the vegetative period. Seed of ‘Centennial’ soybean (Maturity Group VI) was planted in mid‐July in 1992 and 1993 at Baton Rouge, LA, on a Commerce silt loam soil (fine‐silty, mixed, nonacid, thermic Aeric Fluvaquent). Experimental design was a randomized complete block in a split‐plot arrangement. Main plots were row spacings of 100, 50, and 25 cm. Split plots were eight sampling dates during E to R5. The CGR(R1 to R5) advantage of narrow‐row culture developed from CGR advantage in the vegetative period, caused by greater LI originating from increased LIE during the first 26 d of the vegetative period. Yield was significantly correlated with CGR during most of the vegetative period. In conclusion, source strength (CGR) during the vegetative period was shown to affect yield at late planting dates.
Row Spacing and Nitrogen: Effect on Alfalfa‐Bermudagrass Quality Components
Authors: Stringer William C. , Morton Benjamin C. , Pinkerton Bruce W. 
Published: July 2010

AbstractInterseeding legumes into grass sods increases herbage quality. Interseeding alfalfa (Medicago sativa L.) into bermudagrass [Cynodon dactylon (L.) Pers.] has given yields comparable to grass fertilized with high rates of N. Our objective was to compare forage quality attributes of N‐fertilized bermudagrass with alfalfa‐bermudagrass mixtures. N rates of 0, 112, 224, and 448 kg ha−1 were applied to bermudagrass monoculture and to alfalfa interseeded into bermudagrass at 20‐, 40‐, and 60‐cm row spacings. Experiments were conducted on a Cecil sandy clay loam (clayey, kaolinitic, thermic Typic Kanhapludult) and a Norfolk sandy loam (fine‐loamy, siliceous, thermic Typic Kandiudult) site. Hand‐harvested herbage samples were separated into botanical components. Crude protein, acid‐detergent fiber and neutral‐detergent fiber were measured using a combination of wet‐lab and near infrared reflectance spectroscopy (NIRS) procedures. Nitrogen increased the crude protein in bermudagrass monoculture by 11 to 61 g kg−1. The crude protein response of bermudagrass in mixtures to N was slight to nonsignificant. Increasing row spacing of alfalfa reduced grass crude protein by 9 to 23 g kg−1 and had no effect on alfalfa crude protein. Fiber fractions decreased slightly in grass with added N, but fiber in alfalfa was not influenced by any treatment. Yield of crude protein increased with N, particularly in bermudagrass monoculture, but interseeding alfalfa without N produced crude protein yields that usually exceeded those of bermudagrass monoculture at the 448 kg ha−1 N rate. Interseeded alfalfa, even at wide row spacings, appears to produce enough biological N to replace 448 kg fertilizer N ha− or more in the production of herbage protein in bermudagrass.
Soil Moisture, Temperature, and Drying Influence on Soybean Emergence
Authors: Helms Theodore C. , Deckard Edward L. , Goos Robert J. , Enz John W. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] emergence is influenced by the interaction of initial seed zone soil water content and temperature. Stress due to soil water content that is great enough for seed imbibition but too low for radicle emergence from the testa reduces emergence. Previous research has not determined whether emergence is reduced by soil drying after the seeds have imbibed water. Our objective was to evaluate soybean emergence influenced by initial seed zone soil water content and soil drying at three day/night soil temperature regimes (17/8, 21/12, and 25/16°C) as the number of days of soil water deficit and temperature stress increased. The experiment was conducted under controlled temperature conditions using an incubator. Emergence depended on both initial seed zone soil water content and temperature. As the number of days of soil moisture deficit increased, soil drying reduced emergence at initial soil water contents of 0.07 and 0.09 kg kg−1. If the radicle had emerged from the testa and the soil water content was reduced below the initial soil water content due to drying, emergence was reduced. If seed imbibition occurred, but the initial soil moisture was too dry for the radicle to emerge from the testa, emergence decreased as the number of days of stress increased. The results show that the influence of seedbed drying on percent emergence depended on the initial soil water content and the number of days until adequate soil water content was restored.
Potential Uses and Limitations of Crop Models
Authors: Boote Kenneth J. , Jones James W. , Pickering Nigel B. 
Published: July 2010

AbstractCrop models have many current and potential uses for answering questions in research, crop management, and policy. Models can assist in synthesis of research understanding about the interactions of genetics, physiology, and the environment, integration across disciplines, and organization of data. They can assist in preseason and in‐season management decisions on cultural practices, fertilization, irrigation, and pesticide use. Crop models can assist policy makers by predicting soil erosion, leaching of agrichemicals, effects of climatic change, and large‐area yield forecasts. Cautions and limitations in model uses are suggested, because appropriate use for a particular purpose depends on whether the model complexity is appropriate to the question being asked and whether the model has been tested in diverse environments. There is a need for both complex and simple models. In some cases, simple models are not appropriate because they are not programmed to address a particular phenomenon. In other cases, complex models are not appropriate because they may require inputs that are not practical to obtain in a field situation. Modelers need to be forthright in model description and promotion. For example, what does a given model respond to? What are the limitations of the model? What factors does the model not address? What are the limitations of inputs to run the models? Examples are given of model use to evaluate genetic improvement in photosynthesis and seed‐filling duration, yield response to planting date and row spacing, and effects of change in seasonal temperature. We believe that use of crop growth models will play an increasingly important role in research understanding, crop management, and policy questions.
Lentil Water Use and Fallow Water Loss in a Semiarid Climate
Authors: Aase J. Kristian , Pikul Joseph L. , Prueger John H. , Hatfield Jerry L. 
Published: July 2010

AbstractWith renewed interest in legumes for green manures or as partial summer fallow replacement crops, it is important to know water requirements of these crops in semiarid agriculture. Our objective was to evaluate seasonal water use by black lentil (Lens culinaris Medikus cv. Indianhead), a potential fallow replacement crop, and to relate water use to parameters useful as soil water management tools. We measured evapotranspiration (ET) from two precision weighing lysimeters located on a Williams loam (fine‐loamy, mixed Typic Argiboroll) near Sidney, MT. The lysimeters were in adjacent 180‐ by 180‐m fields in a typical strip‐crop environment of the semiarid northern Great Plains. Bowen ratio estimates of ET were also obtained. Lentil was seeded no‐till into wheat (Triticum aestivum L.) stubble on one lysimeter field in 1993, and the other was left in chemical fallow. Seeded and fallow fields were rotated in 1994. Water loss by ET from lentil and fallow lysimeters was the same (≈25 mm) for 3 wk following seeding. Plant height was related to growing degree days (GDD) in both years. Cumulative ET was related to GDD for both years until about 800 GDD, corresponding to nearly 300 mm ET. Deciding how much water to sacrifice (with hopes of recovery during the noncrop period) becomes a matter of judgment about probable rainfall. At full bloom (≈2 Mg ha−1 dry matter production), the lentil crop used about 50 to 70 mm more water than fallow. Probably no more than 50 mm of water loss above that from fallow should be sacrificed if a grain crop is to be seeded the following year. From a practical standpoint, because plant height was closely related to both GDD and cumulative ET, it is plausible that a simple measure of lentil height (about 350 mm maximum) can give sufficient accuracy for determining when lentil growth, as a partial summer fallow replacement crop in a semiarid climate, should be terminated.
Nitrogen Release from Grass and Legume Cover Crop Monocultures and Bicultures
Authors: Ranells Noah N. , Wagger Michael G. 
Published: July 2010

AbstractThe use of grass‐legume bicultures grown as winter annual cover crops may provide farmers with additional cover crop management options regarding the availability of cover crop residue N. A 2‐yr field experiment was conducted to determine dry matter (DM) accumulation, chemical composition, and N release from grass and legume cover crops grown in monoculture (rye, crimson clover, and hairy vetch) and biculture (rye‐crimson clover and rye‐hairy vetch). Air‐dried plant material was placed on the soil surface in 1‐mm mesh nylon bags for 1, 2, 3, 4, 6, 8, and 16 wk. Following retrieval, mesh bag contents were analyzed for total N, C, cellulose, hemicellulose, and lignin concentrations. The 2‐yr mean cover crop DM production was in the order of rye‐hairy vetch > hairy vetch > rye‐crimson clover > rye > crimson clover. The greatest cover crop N content (2‐yr mean) occurred with hairy vetch monoculture (154 kg N ha−1), compared with a low of 41 kg N ha−1 for the rye monoculture. When grown in biculture with rye, hairy vetch accumulated more DM and biomass N compared with crimson clover, both as a proportion of the biculture and as DM yield. In general, the order of N release rates (rapid to slow) was hairy vetch > crimson clover = rye‐hairy vetch > rye‐crimson clover = rye. Estimates of N (kg ha−1) released from cover crop residue after 8 wk of field decomposition, averaged over 2 yr, were 24 for rye, 60 for crimson clover, 132 for hairy vetch, 48 for rye‐crimson clover, and 108 for rye‐hairy vetch. Results of this study demonstrate only slight reductions in N release from grass‐legume bicultures compared with legume monocultures.
A Greenhouse Screening Technique for Acid Soil Tolerance in Maize
Authors: Urrea‐Gómez R. , Ceballos Hernán , Pandey Shivaji , Bahía Filho Antonio F.C. , León Luis A. 
Published: July 2010

AbstractEvaluating maize (Zea mays L.) in the field for tolerance to soil acidity is expensive and provides variable results. To identify alternative screening techniques for maize, the present study adapted a pot bioassay already used for other crops. Two experiments were conducted. One included a set of diallel crosses from eight parents and the other a set of 10 open‐pollinated cultivars. These materials were evaluated under field conditions, in nutrient solution, and in pots containing 2 kg of soil. The best results were obtained after growing plants for 14 d in pots containing soils having intermediate stress (45–65% AI saturation). Fresh root weight, total length (or lateral root length), and visual scoring provided the best separation between tolerant and susceptible genotypes, lacked a significant genotype ✕ soil interaction, and were efficient, simple, and rapid measurements. Significant phenotypic correlations (≈ 0.55) were observed between these variables and yield in the field. While efficiently distinguishing tolerant from susceptible genotypes, the pot bioassay could not clearly detect differences in levels of tolerance. This technique should be useful mainly in the early stages of maize breeding. Results suggest that maize possesses several mechanisms for tolerance to soil acidity.
Responses of Tolerant and Susceptible Maize Varieties to Timing and Rate of Nitrogen under Striga hermonthica Infestation
Authors: Kim Soon‐Kwon , Adetimirin Victor O. 
Published: July 2010

AbstractPurple witchweed [Striga hermonthica (Del.) Benth.], here called just striga, parasitizes cereal crops in the savanna zone of sub‐Saharan Africa. The objectives of this study were to investigate the expressions of a tolerant and a susceptible cultivar of maize (Zea mays L.) to striga as affected by timing (0, 2, 4, and 6 wk after maize planting) and rates (60 and 120 kg N ha−1) of N application under striga infestation. The experiment was designed as a split‐split plot with four replications. Timing of N application and N rates significantly affected striga emergence, host‐plant damage scores, agronomic traits, and grain yield. Nitrogen rate x application time interaction was highly significant for striga emergence. Time of N application was more important than N rate in suppressing striga emergence and host‐plant damage. Nitrogen application at 2 wk after planting and 120 kg N ha−1 gave the best result in terms of maize performance and reduction of striga emergence. Host‐plant damage symptoms were more useful in differentiating response of host genotypes to striga than striga emergence values. The tolerant cultivar (hybrid 8322‐13) produced 188% higher grain yield than the susceptible cultivar (hybrid 8338‐1) across all treatments. Grain yield of the tolerant cultivar at 60 kg N ha−1 was 88% higher than that of the susceptible cultivar at 120 kg N ha−1. The tolerant cultivar produced an average 157% more ears at 60 kg N ha−1 and 51% more ears at 120 kg N ha−1 than the susceptible cultivar. Among all the factors studied, the most important component for striga management was genetic tolerance, the ability of a host plant to withstand the parasite.
Growth and Yield Response of Field‐Grown Tropical Rice to Increasing Carbon Dioxide and Air Temperature
Authors: Ziska Lewis H. , Namuco Offie , Moya Toti , Quilang Jimmy 
Published: July 2010

AbstractAlthough the response of rice (Oryza sativa L.) to increasing atmospheric CO2 concentration and air temperature has been examined at the greenhouse or growth chamber level, no field studies have been conducted under the tropical, irrigated conditions where the bulk of the world's rice is grown. At the International Rice Research Institute, rice (cv. IR 72) was grown from germination until maturity for the 1994 wet and 1995 dry seasons at three different CO2 concentrations (ambient, ambient + 200, and ambient + 300 μL L−1 CO2) and two different air temperatures (ambient and ambient + 4°C) using open‐top field chambers. Averaged for both seasons, increases in CO2 concentration alone (+ 200, +300 μL L~') resulted in a significant increase in total plant biomass (+ 31%, + 40%) and crop yield (+ 15%, + 27%) compared with the ambient control. The increase in crop yield was associated with an increase in the number of panicles per square meter and a greater percentage of filled spikelets. Simultaneous increases in CO2 and air temperature did not alter the biomass at maturity (relative to elevated CO2 alone), but plant development was accelerated at the higher growth temperature regardless of CO2. concentration. Grain yield, however, became insensitive to CO2 concentration at the higher growth temperature. Increasing both CO2 and air temperature also reduced grain quality (e.g., protein content). The combination of CO2 and temperature effects suggests that, in warmer regions (i.e., >34°C) where rice is grown, quantitative and qualitative changes in rice supply are possible if both CO2 and air temperature continue to increase.
Relating Plant Canopy Characteristics to Soil Transport Capacity by Wind
Authors: Armbrust Dean V. , Bilbro James D. 
Published: July 2010

AbstractFederal legislation mandates that wind erosion soil losses be kept to a “tolerable” limit to maintain eligibility for federal farm programs on highly erodible land. Therefore, much interest has been generated in devising wind erosion models that accurately determine the potential erosion from a given site and also evaluate the effectiveness of any control measure. These models require mathematical relationships between surface properties and the transport capacity of the wind. Such relationships are available for soil surface roughness and plant residues, but not for growing crops. Our objective was to establish these relationships for growing crops. We developed a theoretical approach that accounts for the effect of stem area, leaf area, and canopy cover of growing crops on the soil loss ratio, threshold velocity, and transport capacity. The predictive ability of the theory was tested using published data sets from growing plants tested in a wind tunnel. Measured soil loss ratios were highly correlated to predicted values (r2 = 0.99, P = 0.001). The results showed that plant area index and canopy cover are highly correlated with reduction in the transport capacity of the wind and, therefore, serve as indicators of the soil protection afforded by growing plants. A plant area index of 0.02 and a canopy cover of 4% reduced the transport capacity of a 16 m s−1 wind by 50%. This method for determining the protective ability of a combination of growing plants and standing residue will improve predictive capabilities of wind erosion models for more diverse farm management conditions.