bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of Dry Matter Between Shoots and Roots of Irrigated and Nonirrigated Determinate Soybeans1
Authors: Huck M. G. , Peterson Curt M. , Hoogenboom Gerrit , Busch C. D. 
Published: July 2010

AbstractThe timing and duration of drought stress during a growing season can both limit and alter dry‐matter accumulation within plants. Distribution of dry matter between roots and aboveground parts was determined by growing soybean (Glycine max [L.] Merr., cv. ‘Bragg’ or ‘Braxton’) plants for 4 consecutive years (1980–1983) in a sieved, sandy surface soil material, uniformly packed to a bulk density of 1.52 Mg/m3 in soil compartments at the Auburn rhizotron. Three replicated compartments were irrigated by trickle irrigation (IR) whenever the soil water potential (Ψs) fell below ‐ 15 kPa at a depth of 0.4 m. Three additional compartments were not irrigated (NI). Mainstem leaf area and total cumulative root growth were determined at regular intervals. Water stress significantly reduced total shoot weight (347 g/m2) and seed weight (171.2 g/m2) but increased total root length (52 m/m2). Irrigated plants generally had fewer roots, which were generally shallower and more evenly distributed than those of NI plants. Both individual seed weight and total seed weight per treatment were significantly reduced by water stress (0.009 g/seed and 171.2 g/m2, respectively). Apparent harvest index varied between 0.36 and 0.56. A nearly linear relationship was observed between normalized final seed yield (y = 110.8 ‐ 0.738x, r2 = 0.86) or total dry matter (y = 113.3 ‐ 0.685x, r2 = 0.93) production and the percentage of time between flowering (R1) and harvest maturity (R8). Thus, aboveground dry‐matter production and seed yield are directly dependent upon availability of water during critical reproductive states.
Effects of Temperature on Fiber Concentration, Composition, and In Vitro Digestion Kinetics of Tall Fescue1
Authors: Fales S. L. 
Published: July 2010

AbstractHigh temperatures during the growth of forage grasses adversely affect forage quality, but there is little information concerning possible temperature effects on the digestion characteristics of the cell wall. The purpose of this study was to examine the influence of different temperature regimes on the amount, the rate, and the extent of in vitro cell wall digestion in tall fescue (Festuca arundinacea Schreb.). Vegetatively propagated tall fescue plants were grown in a controlled environment over a period of 315 days, during which time the temperature was changed sequentially from 13/10 (T1), to 20/18 (T2), 30/27 (T3), and back to 13/10 (T4)°C, day/night, for a 14‐h photoperiod. Plants were harvested three times at 28‐day intervals at each temperature, after which the temperature was changed. Leaf material from the second and third harvests at each temperature was oven‐dried and ground for analysis. The first harvest at each temperature was discarded in order to reduce the confounding of treatments. Concentrations of neutral detergent fiber (NDF), cellulose, and hemicellulose increased with temperature up to T3 and decreased at T4, while lignin concentration remained about the same. Digestible NDF represented a greater proportion of dry matter in all temperature treatments but showed less variation with treatments than did indigestible NDF. Concentrations of indigestible NDF increased each time temperature was raised and decreased when temperature was lowered. Indigestible NDF concentrations were equivalent to T1 and T4. Rates of digestion of potentially digestible NDF followed first order reaction kinetics, and there were no temperature‐related differences in digestion rate constants. No direct relationship was shown between lignin concentration and digestion. The results indicate that high temperature causes reduced cell wall digestibility by increasing the amount of indigestible cell wall without affecting the rate of digestion of the more labile fraction.
Mineral Analysis of Forages with near Infrared Reflectance Spectroscopy1
Authors: Clark D. H. , Mayland H. F. , Lamb R. C. 
Published: July 2010

AbstractMineral concentration data could easily be generated by near infrared reflectance spectroscopy (NIRS) while determining quality parameters in forage samples. However, which minerals can be analyzed and why they can be determined has not been documented adequately. Therefore, NIRS spectra were collected on 200 samples of crested wheatgrass (Agropyron spp.), 203 tall fescue (Festuca arundinacea Schreb.), and 59 alfalfa (Medicago sativa L.) hays. Concentrations of Na, K, Ca, P, Mg, Fe, Mn, Cu, and Zn, as determined by atomic absorption, and calculated values of the Ca/P, K/Mg, and K/(Ca+Mg) ratios were regressed against reflectance values measured in 2‐nm increments between 1100 and 2500 nm for each sample. Approximately one half of the samples in each forage set was used to develop the calibration equations, while the other half was used to validate the equations. The coefficients of variation [CV=(standard error of analysis÷the mean) X100] generally ranged from 10 to 20% for K, Mg, Ca, and P concentrations in each forage type. The Ca/P ratio in alfalfa was determined with a CV of 18%. The CV values of other minerals and mineral ratios generally exceeded 20%. Chlorophyll and some inorganic salts and organic‐acid salts of Ca, Mg, and K were scanned with NIRS for wavelength comparisons with those wavelengths used to determine mineral concentrations in forages. Some of the wavelengths used in the equations for Ca, K, and Mg were related to peaks and changes in slope observed in chlorophyll and organic‐acid salts of Ca, K, and Mg, suggesting that NIRS is indirectly measuring these minerals by their association with organic molecules. Accurate use of NIRS to determine mineral cation composition in forages appears limited to certain major minerals (Ca, P, K, and Mg).
Simulated Acid Rain Effects on Yield Response of Two Corn Cultivars1
Authors: Banwart W. L. , Porter P. M. , Hassett J. J. , Walker W. M. 
Published: July 2010

AbstractAcid rain is a documented phenomenon over much of the eastern and midwestern United States, including major portions of the Corn Belt. However, few studies report the effect of acid rain on yield of corn (Zea mays L.). Field experiments were conducted in 1983 and 1984 on a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) soil at Urbana, IL. Two corn cultivars (Pioneer 3377 and B73✕Mol7) were protected from ambient rain by two automated movable rain exclusion shelters and were exposed to one of six simulated rain acidities ranging from pH 5.6 to 3.0. Analysis of the effect of rainfall pH on grain yield showed no significant linear or quadratic trend (α=0.10) for either cultivar in individual years or with both years combined. Comparisons among treatments for both cultivars showed rain simulants with no added acid (pH 5.6) resulted in grain yields that were not significantly different from the average grain yields of the other five pH treatments. For B73✕Mol7, the 2‐yr combined yield for the pH 3.0 treatment was significantly lower (5.7%) than the average yield for the other five treatments. This same contrast was not significant for Pioneer 3377. These results imply that under normal environmental conditions and agronomic practices, rainfall at its present levels of acidity has little if any effect on corn yields.
Soil Chemical Factors Associated with Soybean Chlorosis in Calciaquolls of Western Minnesota1
Authors: Inskeep William P. , Bloom Paul R. 
Published: July 2010

AbstractIron chlorosis in soybean [Glycine max (L.) Merr.] is a significant problem in calcareous soils of the upper Midwest. Field studies were established during 1983 in western Minnesota on two sites containing calcareous soils and one site containing gypsic‐calcareous soil (Typic Calciaquolls) to evaluate the soil chemical properties associated with iron chlorosis in soybean. Chlorosis was correlated with increases in soil solution bicarbonate (HCO−3) at the two calcareous sites, but not at the gypsic‐calcareous site. Chlorosis was correlated with increases in total calcite (CaCO3) at all sites. Higher concentrations of soil solution Ca2+ and SO2−4 were found at the gypsic site as a result of greater gypsum (CaSO4. 2H2O) solubility relative to CaCO3 solubility. However, because both CaCO3 and CaSO4. 2H2O were correlated with chlorosis at this site it was difficult to determine which may have been the most important causal factor. Concentrations of mobile soil solution ions such as K+, Na+, Mg2+, and NO−3 were generally greater in chlorotic areas of all sites as a result of accumulation in lower landscape positions associated with chlorosis. Seed yields were correlated with chlorophyll contents measured in the third trifolioliate leaf stage (V4) and during flowering (R1). Chlorosis ratings ranging from 2.5 to 5 resulted in 35 to 40% yield reductions for each unit chlorosis rating (1–5 scale). Increases in plant tissue K, Ca, Mg, Cu, Zn, Mn, and B were associated with increases in chlorosis for all cultivars at all sites. These increases may have been due to a combination of factors including ion balance, concentration of elements in stunted plants, and contamination of chlorotic tissue by soil.
Using Satellite Data to Improve Model Estimates of Crop Yield
Authors: Maas S. J. 
Published: July 2010

AbstractIt has been proposed that remotely sensed information from satellites could complement the performance of crop growth models. A study was conducted to determine how a model could effectively utilize satellite data and if model estimates of crop yield could be significantly improved by satellite data. A simple model was developed for simulating growth and yield of grain sorghum [Sorghum bicolor (L.) Moench] on an individual‐field basis. The model contained three state variables (stage of development, green leaf area index [GLAI], and aboveground dry mass) and utilized daily meteorological observations. When available, GLAI values for target fields could be used to adjust the initial values of the state variables until a “best fit” of the observed data was iteratively achieved by the simulation. GLAI values could be obtained by ground‐based measurements, but satellite observations were demonstrated to be an appropriate source of data for initializing the model. The model was developed and verified using data from 10 fields observed in Central Texas in 1976. The model was tested using a completely independent data set containing yield and satellite observations from 37 fields in South Texas in 1973, 1975, 1976, and 1977. Without using the initializing procedure, the average yield for the 37 fields was underestimated by approximately 30%. Use of satellite‐derived GLAI data to initialize the same simulations resulted in a 2% overestimate of average yield. The results of this study confirm the usefulness of the initializing procedure and satellite data to improve model estimates of crop yield.
Ethephon Influence on Harvestable Yield, Grain Quality, and Lodging of Corn
Authors: Norberg O. S. , Mason S. C. , Lowry S. R. 
Published: July 2010

AbstractTo determine if ethephon ((2‐chloroethylphosphonic acid) would reduce lodging while maintaining or increasing harvestable yield, the influence of timing and rate of ethephon application on harvestable yield, yield components, lodging, and grain quality of corn (Zea mays L.) was studied in 1985 and 1986. Ethephon was applied at rates of 0, 0.14, 0.28, and 0.56 kg ha−1 at tassel elongation (TE), 6 d after tassel elongation (TE+6), and at ear elongation (EE), to Pioneer hybrids P3475, P3377, and P3183 grown in the field near Mead, NE. Application of ethephon reduced lodging of corn plants. Ethephon application of 0.56 kg ha−1 at the EE stage reduced lodging of P3377 and P3183 from 30 to 9%. This rate resulted in production of 52 fewer kernels per ear, and 7 to 17 mg lighter kernel weight, while increasing the number of harvestable ears by 0.2 to 0.6 ears m−2. Increasing the rate of ethephon resulted in a linear decrease in harvestable grain yield, except when applied at the EE stage in 1986, when ethephon application had no influence. In this case, increasing the rate of ethephon resulted in an increased number of harvestable ears per square meter, which compensated for reductions in the number of kernels per ear and kernel weight. Application of 0.56 kg ha−1 ethephon at TE in 1986, TE+6 in both years, and EE in 1985 resulted in approximately 1 Mg ha−1 reduction in harvestable grain yield. Ethephon application had small but significant influence on the protein content, kernel density, and kernel breakage susceptibility of grain produced. Application of ethephon is effective in reducing lodging of corn plants. However, ethephon never increased and usually reduced harvestable grain yields. Based on these results, there is little incentive for producers to consider application of ethephon to corn grown under conditions similar to those in this study.
Spring and Fall Cattle Grazing Effects on Components and Total Grain Yield of Winter Wheat
Authors: Christiansen S. , Svejcar T. , Phillips W. A. 
Published: July 2010

AbstractFarmers and ranchers growing winter wheat (Triticum aestivum L.) in the Great Plains have the practical problem of obtaining maximum grazing with minimum loss of grain yield. The objective of this study was to examine the impact of grazing on subsequent grain, straw, and chaff production of a semidwarf winter wheat (‘TAM W‐101’). Steers (Bos taurus L.) weighing 250 to 350 kg grazed wheat pasture during 3 yr at the Forage and Livestock Research Laboratory near El Reno, OK. Soils at the study site were fine‐silty, mixed, thermic Pachic Haplustolls of the Dale series. Climatic conditions allowed 212 to 338 animal days (AD) ha−1 of fall grazing in 1983 to 1984; 78 to 141 AD ha−1 spring grazing in 1984 to 1985; and 151 to 516 AD ha−1 fall and/or spring grazing in 1985 to 1986. Straw, total grain yield, seed weight, seeds per spike, and spikes m−2 were determined. Heavy (H) and light (L) fall (F) grazing intensities caused lower (P < 0.05) grain yields compared to controls (C) in 1983 to 1984 (2.94[F‐L] and 2.53 [F‐H] vs. 3.51 [C] Mg ha−1); lower, but nonsignificantly different grain production after spring (S) grazing in 1984 to 1985 (2.73 [S‐L] and 2.44 [S‐H] vs. 2.60 [C] Mg ha−1); and mixed results with fall‐only, spring‐only, and two levels of fall and spring grazing in 1985 and 1986 (2.41 [F‐L], 1.37 [S‐L], 1.80 [F,S‐L], and 1.46 [F,S‐H] vs. 1.90 [C] Mg ha−1). Grazing generally decreased the number of spikes m−2. Straw yields were lowered by grazing in all 3 yr, therefore, harvest index of grain was nearly always higher for grazed wheat. Weather differences affected grain production from year to year more than grazing stresses within a year. Components of yield were influenced in an inconsistent manner by the treatments. However, grazing did not damage TAM W‐101 grain yield, when moderate grazing was used, trampling was avoided, excess autumn forage was removed and/or no severe weather adversities added to grazing stress on the crop.
Corn Residue Effect on the Yield of Corn and Soybean Grown in Rotation
Authors: Crookston R. K. , Kurle J. E. 
Published: July 2010

AbstractCrop rotation provides a yield benefit that persists at optimal management levels. The exact reason for the rotation effect is unknown. One theory is that a given crop's own residue has an autoinhibitory effect when that crop is maintained under monoculture, and/or that residues of alternate crops have a stimulatory effect on one another under rotation. We conducted field studies at Lamberton, Rosemount, and Waseca, MN to test this theory. Soils at these locations are: Webster clay loam (fine‐loamy, mixed mesic Typic Haplaquolls), Waukegan silt loam (fine‐silty, over sandy, mixed, mesic Typic Hapludolls), and NicoIIet clay loam (fine‐loamy, mixed, mesic Aqnic Hapludolls), respectively. A series of 3‐yr crop sequences were established at each site. In the first year the experimental area was kept fallow. In the second year half of each replicated plot was planted to corn (Zea mays L.) and half to soybean (Glycine max (L.) Merr.) After grain harvest all above‐ground corn residue was removed from half of the corn area and transferred to half of the soybean area. All plots were then moldboard plowed. In the spring of the third year all plots were disked and planted uniformly in corn (1981, 1982) or soybean (1983, 1984). There was a significant effect of previous crop (rotation effect) on the yield of both corn and soybean, but the removal or addition of corn residue had no effect on the yield of either crop. This indicates that the yield response of corn and soybean to rotation is not due to beneficial or negative effects of decomposing above‐ground residue.
Nitrate Concentration in Potato Petioles from Periodic Applications of 15N‐Labeled Ammonium Nitrate Fertilizer
Authors: Roberts S. , Cheng H. H. , Farrow F. O. 
Published: July 2010

AbstractConcerns for N use efficiency prompted a tracer study of the effectiveness of applying supplemental N fertilizer throughout the growing season. The purpose of the study was to monitor the concentration of 15NO3‐N in petioles of Russet Burbank potato (Solanum tuberosum L.) following periodic treatments of 15N‐labeled NH4NO3 on Quincy loamy sand (mixed, mesic Xeric Torripsamments). The experiments were conducted for 5 yr with main plot N rates of 224, 336, and 560 kg ha−1 as NH4NO3 split into starter and supplemental applications. Split plot treatments consisted of labeling the NH4NO3 with 15N at various times. Results indicate that supplements of 15NH4 15NO3 were taken up by the plants and concentrated in petioles within 1 wk after application at various times throughout the growing season. The 15N from pre‐emergence starter fertilizer applied in May was evident in petiole NO3 at each petiole sampling through the entire season. Uptake of the 15NO3 source reached a higher peak in petioles 1 wk to 10 d ahead of 15NO3 that was nitrified and taken up from applying the same rate of labeled 15NH4 source. The uptake of labeled NH4 in petioles was not determined. These data suggest that monitored petiole NO3 values could underestimate the soil N available from NH4 fertilization. These results with 15N tracer indicate that the process of N uptake is a dynamic one which continues as long as plants are active throughout the growing season.
Simulation of Carbon Assimilation and Partitioning in Maize
Authors: Grant R. F. 
Published: July 2010

AbstractCrop simulation models offer a means of integrating scientific findings into a coherent description of crop adaptation to a complex environment. The detailed simulation of growth processes involved in carbon accumulation and partitioning is an essential prerequisite for modelling such adaptation. A procedure for simulating these processes in maize (Zea mays L.) was developed as part of a larger maize growth model. Hourly values for the gross photosynthetic rate of a maize canopy are accumulated into a pool from which hourly values of carbohydrate mobilized for both shoot and root growth are removed. Maintenance and growth respiration of both the shoot and root are then subtracted from the respective allocations of mobilized carbohydrate and the remainders accumulated into daily totals of dry matter growth. These daily totals are partitioned to and accumulated in the major plant organs depending upon growth stage. Growth partitioned to the leaves is converted to leaf area growth. Kernel number and maximum kernel mass are determined from growth functions during stages of ear formation and kernel set. Maturity is presumed to occur when maximum kernel mass is reached or when kernel growth is stopped due to inclement weather. Model output for partitioning, biomass, grain yield, kernel number, kernel mass, and leaf area index were compared with observed values at several sites across North America. Although many of the processes upon which the model is based require greater understanding, the model is able to provide estimates of these variables that are usually within 20% of recorded values. Greater accuracy in simulating maize growth will require further elucidation of the way in which environment influences basic growth processes as well as more detailed information regarding site‐specific soil and meteorological characteristics.
Corn Growth Response to Temperature: Rate and Duration of Lead Emergence
Authors: Hesketh J. D. , Warrington I. J. 
Published: July 2010

AbstractSeasonal predictions of gas and energy exchange in crop canopies require a quantitative description of temperature effects on leaf area development. Such predictions are needed in crop management and forecasting models. Our objectives were to quantify temperature effects on leaf emergence rates, determined as lengths and areas of fully expanded emerged leaf material, and their duration in corn (Zea mays L.). Hybrids were grown in controlled environments under 16 temperature regimes ranging from 16/11 to 38/33 °C (12‐h day/night thermal periods). Plants were dissected every 3 to 10 d, depending on the temperature, to determine the mainstem node number associated with the youngest leaf primordium as well as weight, area, and length per leaf. The node number of the youngest leaf showing a ligule was recorded. Leaf emergence rates, either as lengths or areas per unit time, and the node associated with the youngest visible leaf tip were derived from time plots of emerged leaf lengths and area. Emergence duration was estimated three ways: (i) the time between appropriate leaf developmental events, from time plots, (ii) mature leaf length divided by its extension rate, and (iii) mature leaf area divided by its area emergence rate. Primordia and ligule appearance rates derived from these data were published earlier. The relationships between temperature and tip appearance rates, leaf emergence rates, and the reciprocals of the various estimates of duration were determined; threshold temperatures and degree day requirements for processes derived from such plots are presented. Other information is provided for developing logic for predicting temperature effects on the development of canopy leaf area in corn.
Amyloglucosidase Hydrolysis Can Overestimate Starch Concentration of Plants
Authors: Denison R. F. , Fedders J. M. , Tong C. B. S. 
Published: July 2010

AbstractReported β‐glucanase activity by amyloglucosidases used in starch determination might lead to significant overestimates of starch concentration in plant tissue. To test this hypothesis, two amyloglucosidases and a porcine α‐amylase were evaluated using four starch and three β‐glucan preparations. The enzymes were also used to estimate starch concentration of alfalfa (Medicago sativa L.) roots and tall fescue (Festuca arundinacea Schreb.) and orchardgrass (Dactylis glomerata L.) stem bases. Release of reducing sugars by the α‐amylase was consistent with 95 to 98% hydrolysis of starch to maltose, and <3% hydrolysis of β‐glucans. The widely used amyloglucosidase from Rhizopus gave 89 to 93% hydrolysis of starch, but also 35 to 83% hydrolysis of β‐glucans. Hydrolysis with α‐amylase gave calculated starch concentrations for the grasses which were not significantly different from zero, but the Rhizopus enzyme gave starch estimates of 32 and 52 g kg−1 for tall fescue and orchardgrass, respectively. The amyloglucosidase from Aspergillus gave intermediate results. Neither amyloglucosidase should be used to estimate plant starch concentration.