bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil‐Plant Buffering of Inorganic Nitrogen in Continuous Winter Wheat
Authors: Raun William R. , Johnson Gordon V. 
Published: July 2010

AbstractThe soil‐plant system can limit soil profile inorganic N accumulation when N fertilizers are applied at rates greater than needed for maximum yield. Nitrogen rates that maximized grain yield and increased soil profile inorganic N accumulation under continuous dryland winter wheat (Triticum aestivum L.) were evaluated in four long‐term experiments. Soil cores (0‐210 cm) were taken in 1988 and again in 1993 from N rate treatments where wheat had been grown for more than 23 yr. Soil cores were split into 15‐ to 30‐cm increments and analyzed for NH4‐N, NO3‐N, total N, and organic C. Critical N fertilization rates were determined from linear‐plateau models of wheat grain yield on annual N applied. Plateau‐linear models were established for soil profile inorganic N accumulation (sum of NH4‐N + NO3‐N, converted to kg ha−1) on annual N applied. Maximum yields were observed at N rates less than that required to increase soil profile inorganic N accumulation. Annual N fertilization rates that increased inorganic N accumulation exceeded the N requirement for maximum yields by more than 23.3 kg N ha−1 in all experiments. Increased plant N volatilization and grain N uptake have been found when N rates exceed yield maximums. High N rates can also increase straw yield and straw N, subsequently increasing surface soil organic C and N and the potential for denitrification when wheat straw residues are incorporated. In dryland production systems, soil‐plant buffering (considering the processes discussed) implies that the system buffers against (resist) soil accumulation of inorganic N, even when N rates exceed that required for maximum grain yield.
Forage Production, Grain Yield, and Protein Content in Dual‐Purpose Triticale Grown for Both Grain and Forage
Authors: García del Moral L. F. , Boujenna A. , Yañez J. A. , Ramos J. M. 
Published: July 2010

AbstractThe use of cereal crops for both forage and grain production is practiced in many parts of the world. Quantity and quality of forage and grain with this dual use is strongly influenced by seeding date, cutting frequency and growth stage. The effect of two seeding dates and three cutting frequencies on forage production, grain yield, forage and grain protein content, and several associated characteristics of triticale (✕ Triticosecale Wilt.) was determined in 1990 and 1991 at three field locations in southern Spain. Seeding date was less influential on forage and grain production than cutting treatments. Forage harvest significantly reduced grain yield 19.1 to 54.7% with one cutting and 46.6 to 76.2% with two cuttings. Plant height was reduced 5.6 to 18.8% with one cutting and 16.4 to 43.3% with two cuttings. Grain protein yield was reduced 18.6 to 53.7% with one cutting and 47.9 to 72.8% with two cuttings. Grain protein content increased 5.6 to 23.3% with one cutting and 8.0 to 32.0% with two cuttings at the rainfed sites, but not under irrigated conditions. Forage protein content was negatively related to forage yield both in rainfed (r = −0.824) and irrigated (r = −0.952) environments, probably due to a dilution effect. An inverse linear relationship was found between grain yield and protein content (r = −0.901) in the four rainfed experiments, probably from differences in accumulation of starch. Under irrigated conditions and high soil fertility, cuttings did not affect the final percentage of protein in the grain, although grain yield decreased. An inverse relationship was found between the rainfall measured during the triticale growing season and the mean protein content in the grain (r = −0.911) under rainfed conditions.
Soybean Reproductive Development: Adapting a Model for European Cultivars
Authors: Colson Josiane , Bouniols Andrée , Jones James W. 
Published: July 2010

AbstractThe objective of this study was to simulate reproductive development and yield potential of new soybean [Glycine max (L.) Merr.] lines that might be grown in different European locations. The SOYGRO model was adapted to European crop conditions with respect to genetic parameters for pod set, pod growth, seed set, and seed enlargement. The structure of reproductive development in the model takes into account the hierarchy in assimilate partitioning for pod addition, shell growth, and seed initiation. This aspect was described in relationship with canopy photosynthesis, temperature, and photoperiod. A sensitivity analysis was conducted on yield variations with 11 parameters representing phenological traits, characteristics of pod and seed development, and foliage growth in order to identify the main genetic parameters. Field determinations of pod numbers computed from R5 to R7 on current cultivars and new lines belonging to indeterminate and determinate types showed two kinds of fruiting processes, which appear to be independent of growth habit and maturity group. Based on the comparison of the dynamics of observed pod addition for the reference cultivars, a simple procedure was proposed to calibrate the genetic parameters for new cultivars. This new procedure allowed validation of pod production and yield and provided good agreement with field data collected in several locations in Europe.
Role of Warm‐Season Weeds in Spotted Wilt Epidemiology in the Southeastern Coastal Plain
Authors: Johnson W. Carroll , Todd James W. , Culbreath Albert K. , Mullinix Benjamin G. 
Published: July 2010

AbstractThe role of endemic weeds in the epidemiology of spotted wilt must be determined in order to develop an integrated system to manage the disease. Field studies were conducted from 1990 through 1992 to determine concurrently the incidence of spotted wilt and population dynamics of thrips (Thysanoptera: Thripidae) on seven warm season weeds and three crop species planted in microplots. Weeds examined were Senna obtusifolia (L.) H. Irwin & Barneby (syn. Cassia obtusifolia L.] (sicklepod), C. occidentalis L. [syn. S. occidentalis (L.) Link.] (coffee senna), Jacquemontia tamnifolia (L.) Griseb. (smallflower morningglory), Ipomoea lacunosa L. (pitted morningglory), Sida spinosa L. (prickly sida), Desmodium tortuosum (Sw.) DC. (Florida beggarweed), and Xanthium strumarium L. (common cocklebur). Crops evaluated were Arachis hypogaea L. (peanut), Nicotiana tabacum L. (tobacco), and Capsicum annuum L. (bell pepper). All of the weed species were endemic to the southeastern Coastal Plain and all crops were commercially produced in the vicinity of the test site. Most of the weeds were closely related to species identified as hosts of tomato spotted wilt tospovirus (TSWV). TSWV was rarely detected in any of the weed species, while incidence in all crops increased at a linear rate throughout the growing season. Order of spotted wilt incidence in crops was peanut > tobacco > bell pepper. Thrips species diversity differed among weeds and crops. Thrips vectors were highly attracted to susceptible crops, especially peanut. While the weed species we studied were susceptible to spotted wilt, they were not preferred hosts for the thrips vectors. Any occurrence of spotted wilt in weeds is probably due to random feeding by the vector. The warm‐season weeds studied did not contribute significantly to the epidemiology of spotted wilt.
Nitrogen Fertilizer Management to Improve Crop Tolerance to Corn Rootworm Larval Feeding Damage
Authors: Riedell Walter E. , Schumacher Thomas E. , Evenson Paul D. 
Published: July 2010

AbstractWidespread use of crop management practices that reduce the effect of corn rootworm (Diabrotica spp.) larval feeding damage on maize (Zea mays L.) plant lodging or grain yield production would reduce grower reliance on chemical pesticides. Nitrogen fertilizer placement can affect root system morphology and distribution within the soil profile. This study was conducted to determine if N fertilizer placement can be used as a tool to improve maize tolerance to rootworm infestation. The effects of planting time broadcast or split‐applied (planting‐cultivation) banded N (UAN; 28‐0‐0 N‐P‐K) treatments on root larval feeding damage, root pull resistance, lodging, grain yield, and survival of larvae to adult stage under different levels of controlled rootworm larval infestation were investigated. Results of the 3‐yr field experiment suggest that root systems were generally larger (greater root pull resistance) under banded N (85 kg plant−1) than under broadcast N (68 kg plant−1) at the time when rootworm larval feeding had ceased. Lodging (stem greater than 30° from vertical) in broadcast N plots (51%) was greater than that seen in banded N plots (41%). If tolerance to rootworm larval feeding damage is defined by the presence of a large root system and by the ability of the stem to stand erect, then banded N fertilizer placement can help improve tolerance to corn rootworm larval feeding damage.
Concentrations and Ruminal Degradabilities of Amino Acids from Wheat and Triticale Forage and Grain
Authors: Miller Grady L. , Bunting L. Dwain , Joost Richard E. , Ward Terry L. 
Published: July 2010

AbstractA study was conducted to provide comparative data on amino acid (AA) concentrations in forage and grain of wheat (Triticum aestivum L.) and triticale (✕Triticosecale Wittmack), before and after ruminal degradation, while assessing forage and grain yield potential. Forage samples of Terral ‘817’ wheat, ‘Jenkins’ triticale, and ‘Morrison’ triticale were harvested at growth stages 5.0, 6.5, and 8.0 and AA concentrations and yield determined. Wheat and triticale forage samples were incubated in Dacron bags for 24 h in the rumen of cows to determine the comparative ruminal degradability of their EAA. Forage production among the three cultivars in 1987‐1988 was similar, but in 1988‐1989, Jenkins produced 15% more forage than Terral 817, which produced 14% more forage than Morrison. Essential amino acid concentrations in Jenkins triticale forage were equal to or greater than Terral 817 wheat or Morrison triticale; however, Morrison grain had a greater concentration of all EAA, except lysine, than did grain of Terral 817 or Jenkins. The EAA in Terral 817 forage averaged 25% higher in potential degradability in the rumen than EAA in Jenkins. Terral 817 and Morrison maintained a higher grain yield response to forage removal in contrast to Jenkins. Differences in forage yield, grain yield, and EAA concentration could not always be separated by species. The data suggest that triticale may produce forage and grain yields equal or greater than that of winter wheat while providing a better source of ruminally undegradable EAA.
A Proposed Method for Measuring the Effect of Soil Quality on Productivity
Authors: Olson Barry M. , Janzen H. Henry , Larney Francis J. , Selinger Lorna J. 
Published: July 2010

AbstractThe evaluation of soil quality requires definitive, measurable criteria. Our objective was to develop a field assay for identifying the specific soil attributes that govern the quality of soil for biomass production. The technique involved the removal of surface soil and subsequent deposition of soils with diverse attributes. As an initial evaluation of this approach, 36 diverse soils were deposited in a replicated design at each of two sites (dryland and irrigated), and the soils were seeded to cereals for three subsequent years. Crop growth was highly responsive to variation in soil properties. Dry matter yields on dryland in the year after establishment, for example, ranged from 5.4 to 9.4 Mg ha−1 (excluding two subsurface soils). These findings demonstrate that variation in soil quality has a quantifiable influence on productivity, and suggest a useful supplementary role for the proposed approach in identifying soil quality criteria.
Winter Wheat Responses to Surface and Deep Tillage on the Southeastern Coastal Plain
Authors: Frederick James R. , Bauer Philip J. 
Published: July 2010

AbstractConservation tillage practices have seldom been used to produce winter wheat (Triticum aestivum L.) on the U.S. southeastern Coastal Plain, primarily because of inadequate planting equipment and the need for deep tillage. Despite improved equipment, little is known about the effects of surface and deep tillage (ST and DT) systems on winter wheat development and grain yield on the Coastal Plain. Objectives of this 2‐yr study were to (i) determine whether ST affects the grain yield response of winter wheat to DT and (ii) examine the effects of ST and DT on winter wheat development. The soil was a Goldsboro loamy sand (fine‐loamy, siliceous, thermic Aquic Kandiudult). Treatments were ST (disked twice or no surface tillage) and DT (deep tilled using a ParaTill or no deep tillage). Averaged over years and levels of DT, the number of emerged seedlings was 16% less with no ST than with disking. With DT, the number of heads per square meter was similar for the two levels of ST treatment, indicating that wheat grown with no ST produced more heads per plant than with disking. Soil water contents were usually lower in 1995 than in 1994 for all treatments (<2 g kg−1 prior to inflorescence emergence in 1995). Aboveground dry weights near inflorescence emergence, kernel no. m−2, and grain yields averaged 39, 26, and 22% less, respectively, in 1995 than in 1994. Deep tillage increased aboveground dry weight, kernel no. m−2, and grain yield more for wheat in no‐surface‐tillage plots than in disked plots. When deep tilled, ST had no effect on grain yield in 1994, but yields were 25% greater for wheat grown with no ST in the drier year of 1995. There may be no need to disk the soil if DT is performed and proper planting equipment is used to produce winter wheat on the southeastern Coastal Plain. Yield increases due to DT in this region should be greater with no ST than with disking.
Comparison of Residue Decomposition Models Used in Erosion Prediction
Authors: Schomberg Harry H. , Steiner Jean L. 
Published: July 2010

AbstractCrop residues protect soil from water and wind erosion. How long the residues remain effective depends on their decomposition rate. The crop residue decomposition submodels developed for the Revised Wind Erosion Equation (RWEQ) and Revised Universal Soil Loss Equation (RUSLE), which are used to determine the effectiveness of conservation practices, use different approaches to account for water and temperature effects on decomposition. Because of these differences, residue losses may not agree between the two models for a given location. We compared the climatic indices used in RWEQ and RUSLE to determine the similarity of results for simulated climatic scenarios, as well as for field data. Simulated climatic regimes were used to evaluate the relative responsiveness of the temperature and water functions. The two models estimated different numbers of decomposition days (DD) when water and temperature were not limiting. RUSLE usually predicted more DDs than RWEQ. Under water‐limiting conditions, the estimation of DD was similar for the two models. In comparisons with field decomposition data, mass loss predictions by RWEQ were as good as or better than those by RUSLE for locations in Texas, Oregon, and Georgia. RUSLE overpredicted decomposition by 20 to 50% when residues were irrigated. RWEQ underpredicted decomposition by 20 to 50% in the Pacific Northwest. Interactions between the climatic indices (CF) and decomposition coefficients influenced the differences between measured and predicted values. Differences in the CF were related to the method of calculating the water coefficient (WC) and interpretation of the interaction between the temperature coefficient and WC. The models could be improved by developing water and temperature functions that give results closer to those produced with daily time‐step functions.
Spatial Variation Affects Precision of Perennial Cool‐Season Forage Grass Trials
Authors: Casler Michael D. 
Published: July 2010

AbstractRandomized complete block (RCB) designs, although commonly used in testing forage grass cultivars, often are inefficient. The objective of this study was to evaluate the RCB design, the lattice design, trend analysis, and nearest‐neighbor analysis (NNA) for their ability to account for spatial variability in 27 perennial cool‐season forage grass cultivar evaluation trials conducted over a 15‐yr period at Arlington, WI. Each trial was made up of cultivars or experimental populations of one of six species or groups of species: orchardgrass (Dactylis glomerata L.), ryegrasses [a group comprising perennial ryegrass, Lolium perenne L.; intermediate ryegrass, L. hybridum Hausskn.; and festulolium, ✕ Festulolium braunii (K. Richt.) A. Camus], smooth bromegrass (Bromus inermis Leyss.), reed canarygrass (Phalaris arundinacea L.), tall fescue (Festuca arundinacea Schreb.), and timothy (Phleum pratense L.). Dry matter forage yield was determined for 3 yr on each trial and expressed, for each plot, as mean annual yield. Yield data for each trial were analyzed by the RCB or lattice model, trend analysis, and two NNA models (one or two covariates). Three incremental improvements in precision of entry means were observed: an average of 15% due to the RCB design, an additional average of 17% due to the lattice design, and an additional average of 22 to 30% due to trend analysis or NNA. Trials were highly variable in the relative efficiency of both their experimental design and the spatial analyses, but this variability was not related to species, planting years, or plot size. The only useful predictor of trial efficiency was number of entries: three of five trials with eight or fewer entries failed to show significant differences among entries, regardless of the analysis. Spatial analysis methods cannot overcome lack of true differences among entries or failure to detect differences due to low degrees of freedom. Trend analysis or NNA appear to be useful mechanisms to account for intrablock variability in fields where it is impossible or uneconomical to predict proper blocking patterns.
Evaluation of Fine Root Length and Diameter Measurements Obtained Using RHIZO Image Analysis
Authors: Bauhus Jürgen , Messier Christian 
Published: July 2010

AbstractImage analysis systems facilitate rapid measurement of root length and diameter, but their accuracy is not easily determined. The objective of this study was to develop a set of simple experiments for evaluating the accuracy of fine root measurements obtained using image analysis. Using the system RHIZO (trademark of Régent Instruments, Québec), we tested the accuracy of (i) length measurements made over a range of root lengths per unit area, (ii) average diameter measurements and length per diameter distributions in string, wire, and fine root samples of varying diameter, and (iii) diameter measurements on short segments of diagonally oriented objects. Our results suggest that preliminary testing of image analysis systems is absolutely necessary for producing reliable root measurements. Total length was accurately determined for typically encountered length per unit areas of <1.5 cm cm−2. For samples with higher values, however, the method underestimated total length by >5%. It is therefore recommended that users of image analysis systems determine this maximum length per unit area for accurate delerminations of total root length. In samples that contained different string diameters, the total sample length and average string diameter could accurately be measured. However, the length per diameter class was underestimated by >20% when the string diameter was less than one pixel smaller than the upper limit of the diameter class. Adjustment of diameter intervals and increasing the scanner resolution are required to reduce this underestimation. Both the length and the angle of the short segments analyzed were found to influence diameter measurements. Similar sets of experiments are proposed for a rigorous evaluation of the performance of other image analysis systems on root measurements.
Some Thermodynamic Properties of Soil Water
Authors: Taylor Sterling A. , Stewart Gordon L. 
Published: July 2010

AbstractThe partial specific Gibbs free energy or moisture potential of soil water has been measured by methods that are widely accepted. There are several other thermodynamic properties that are of significance in soil moisture relationships that are not so readily measured and are not well understood. The partial specific entropy and enthaply (heat content) of soil water are two such properties of interest. They have been calculated from the temperature dependence of the moisture potential.The moisture content, solute content and pressure of soil samples were held constant. The temperature of the system ranged between 2° and 45° C. It was changed periodically and controlled at well‐defined intervals. After each change in temperature, the system was allowed to come to equilibrium and the moisture potential, as measured by tensiometers, was determined. From the temperature dependence of the moisture potential, the partial entropy change of soil water was found to be more negative than that of free water. Significant entropy differences were found in soils that contained water at a moisture potential of 0.008 joules per g. (0.08 bars suction) at about 20° C. The partial specific entropy and enthalpy of soil water were found to be dependent upon moisture content and temperature.
Amino Components of Soil Organic Matter Formed During Humification of 14C Glucose
Authors: Wagner G. H. , Mutatkar V. K. 
Published: July 2010

AbstractAfter a 6‐month period of incubation of 14C glucose in soil, the soil organic matter was acid hydrolyzed and amino compounds were isolated by ion exchange chromatography. The 13 major amino compounds contained 17 to 22% of the radioactive carbon that had become incorporated into the soil organic matter. Although all of the amino compounds were labeled with 14C the amount of label was not the same in all cases. Amino compounds with the highest specific activities were those which are known to predominate in bacterial and fungal cell walls. The results suggest that the cell walls of microorganisms utilizing glucose are more resistant to further decomposition than are the cytoplasmic proteins.
Nonlinear Denitrification Kinetics with Continuous Flow in Soil Columns
Authors: Starr J. L. , Parlange J.‐Y. 
Published: July 2010

AbstractAn undisturbed core of surface soil was placed in an acrylic plastic perforated column. Saturated air or N2 was passed horizontally through the soil while a NO3‐‐N solution was leached vertically through the soil. Aerobic breakthrough curves were used to measure the convective diffusion and the denitrification rates were measured by switching to anaerobic conditions after the NO3‐ concentration in the effluent equalled that in the influent. The theoretical model was developed which did not assume a priori the functional relationship between the reaction rate and the NO3‐ concentration. The validity of the model was checked by sending a pulse of NO3‐ into the column, with no NO3‐ present initially. The breakthrough curve was predicted using the convective diffusion and denitrification rate previously measured under different boundary condition. The good agreement between theory and experiment showed that the deviation from first‐ or zero‐order kinetics is of crucial importance in predicting the breakthrough curve.