bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Botanical Composition in Alfalfa/Ryegrass Mixtures by Near Infrared Spectroscopy
Authors: Shaffer J. A. , Jung G. A. , Shenk J. S. , Abrams S. M. 
Published: July 2010

AbstractDetermining the botanical composition of forage samples by near infrared reflectance spectroscopy (NIRS) can save time and expense. The purpose of this study was to test the efficacy of NIRS technology for predicting botanical composition of forage samples. Estimating the number of samples required for reliable calibration equations, determining if pooling calibration samples across locations and years (broad‐based) would improve accuracy and precision, and comparing NIRS errors with experimental and sampling errors were primary objectives. Samples were collected from four different alfalfa (Medicago sativa L.) and ryegrass (Lolium perenne L.) management trials. Calibration samples were hand‐separated into alfalfa, ryegrass, and weed components and each component was dried and weighed. Alfalfa and ryegrass components were then remixed, ground, and processed through a scanning monochromator. Calibration equations for percent alfalfa were chosen using statistical analysis, Random subsets of samples were selected for validation of calibration equations using R2, bias, and standard error of performance (SEP). Broad‐based calibration equations required as little as 200 samples (approximately 5%) to accurately predict botanical composition of alfalfa/ryegrass mixtures with R2 of 0.95, SEP of 6.5%, and bias of −0.3%. Calibration equations generated from each of the four studies separately only marginally improved SEP and slightly increased bias. When botanical composition was estimated on samples from locations not included in the calibration data set, large increases in SEP and bias were observed. Errors associated with NIRS estimations were often one‐half as large as the experimental and sampling errors.
Leaf Appearance Rates of Two Winter Wheat Cultivars under High Carbon Dioxide Conditions
Authors: Boone M. Y. L. , Rickman R. W. , Whisler F. D. 
Published: July 2010

AbstractThe mechanisms describing leaf appearance and tillering are vital to the modeling of wheat canopy development. How these two factors will be affected by increasing global atmospheric [CO2] in cool or warm climates is not fully understood. Two southeastern USA adapted wheat (Triticum aestivum, L.) cultivars, Coker 762 and Stacy, were grown under nearly nonlimiting conditions including elevated [CO2] (600 μL L−1) and under six air temperature regimes (ranging from 4/−1 to 18/7 °C d/night and progressively increasing to 16/4 to 29/18 °C d/night during the season) to observe leaf and tiller appearance rates and to compare tillering rates to those predicted by the Fibonacci series as approximated by Binet's equation. Both cultivars exhibited an abrupt one‐time change in their phyllochron interval for all six temperatures. This change occurred just prior to double ridge formation. The vegetative growth phase phyllochron interval of the two cultivars was significantly different only in the (21/10 °C) temperature treatment. In the two lowest temperature treatments (16/4 and 18/7 °C), the cultivars differed in phyllochron interval during the reproductive growth phase. The tillering rate of wheat followed closely the theoretical development predicted by Binet's equation during the vegetative phase of development.
Tillage Effects on Some Soil Physical and Corn Physiological Characteristics
Authors: Cox W. J. , Zobel R. W. , van Es H. M. , Otis D. J. 
Published: July 2010

AbstractTillage systems influence soil temperature and available soil water, which can influence photosynthetic rates and growth of corn (Zea mays L.). Field experiments were conducted in 1987 and 1988 in New York on a tile‐drained silt loam soil (fine‐loamy, mixed, nonacid, mesic Aeric Haplaquept) to determine to what extent conventional tillage (CT), no‐till (NT), and ridge tillage (RT) systems influence soil temperature and soil water conditions, thereby influencing CO2 exchange rates (CER) and growth of corn. Soil temperature at the 0.1‐m depth under NT averaged about 1 °C lower than CT and RT during the first 50 d after emergence (DAE). In 1987, when water stress was not a factor, the lower soil temperature under NT resulted in lower leaf, stem, and total phytomass throughout the vegetative period. Kernel growth rates, however, did not differ between tillage treatments (33.2, 30.9, and 31.4 g m−2 d−1 for CT, NT, and RT, respectively) which resulted in no differences in kernel phytomass at physiological maturity (1125, 1000, and 1030 g m−2 under CT, NT, and RT, respectively). During the hot and dry 1988 growing season, soil water pressure under CT at the 0.25‐m‐soil depth decreased to −0.1 MPa at 44 DAE, 13 d earlier than under NT anti RT. Cone index values were higher under NT and RT from the 0.07‐ to 0.22‐m‐soil depth which indicates increased soil mechanical resistance under NT and RT. The CER were significantly lower under NT or RT compared to CT on 8 of 10 measurement dates during a dry period in 1988 (34‐54 DAE) which was reflected in lower leaf, stem, and total phytomass during the vegetative period. Likewise, NT had a lower kernel growth rate (19.6 compared to 27.4 and 23.4 g m−2 d−1 under CT and RT, respectively), which resulted in lower kernel phytomass at physiological maturity. The data suggest that increased soil mechanical resistance can develop under a continuous NT and RT system which can decrease soil water uptake, CER and growth of corn when dry conditions occur during vegetative development.
Spectral Estimates of Daily Carbon Dioxide Exchange Rates in Wheat Canopies
Authors: Wall G. W. , Lapitan R. L. , Asrar G. , Kanemasu E. T. 
Published: July 2010

AbstractSpectral indices have been used to predict leaf area index (LAI) and the interception efficiency (e1) of photosynthetically active radiation (PAR) within a plant canopy. The objectives of this work were to investigate the influence of canopy geometry on the temporal trends in LAI and spectral indices, and to develop equations to predict the daily canopy gross carbon dioxide exchange rates (DGCE) from daily PAR. Winter wheat (Triticum aestivum L. cv. Newton) was planted in north‐south and east‐west row orientations with 0.18‐, 0.35‐, 0.53‐, and 0.71‐m row spacings, during 1982—1983 and 1983—1984. Net CO2 exchange rates were measured with a transparent dynamic positive‐pressure chamber and a differential infrared gas analysis system. Daytime dark respiration rate correction were made to obtain the DGCE. Canopy spectral reflectance was monitored with a multispectral radiometer, while absorption of PAR was measured with quantum sensors. Daily absorbed PAR was derived by taking the product of e1, estimated from either the LAI or spectral indices, and total incoming PAR. Row orientation did not significantly influence the temporal trends in LAI or the spectral response, whereas significantly greater LAI and spectral response occurred in the narrower‐ vs. wider‐spaced canopies. A linear model characterized the relationship between DGCE and daily absorption of PAR. A common slope model (0.74 g CO2 mol−1 photon) indicated that the LAI and spectral indices had similar predictive capabilities. Good agreement occurred between an equation developed with 1984 data and measured values from 1983 (i.e., R2 0.49—0.65). Remotely sensed multispectral canopy reflectance data, therefore, can be used to estimate DGCE in wheat canopies.
Crop Water Stress Index and Forage Quality Relationships in Alfalfa
Authors: Halim R. A. , Buxton D. R. , Hattendorf M. J. , Carlson R. E. 
Published: July 2010

AbstractRecent developments in assessment of plant‐water stress employ infrared thermometers to measure the difference between air and canopy foliage temperature (Tc – Ta). Crop Water Stress Index (CWSI), which normalizes Tc – Ta values for climatic variability, is related to forage yields of alfalfa (Medicago sativa L.). The objective of this study was to determine whether forage quality of alfalfa also is related to CWSI. ‘Apollo II’ alfalfa was grown in 100‐L potometers set into the ground and protected by a movable rainout shelter. Plants were watered either weekly or twice weekly to 112, 100, 88,76, and 64% of field capacity during 2 yr. Daily readings of canopy and air temperature were taken, and vapor‐pressure deficits were determined from the time plants were 15 cm tall until harvest. Plants were harvested after 5 wk of regrowth and were divided into stem bases (lower six nodes and internodes), stem tops, and leaves before forage quality analyses were conducted. Dry‐matter yield and plant maturity declined linearly with increasing CWSI (r2 = 0.86 and 0.65, respectively). Leaf‐to‐stem ratio increased with increasing CWSI (r2 = 0.51), but year effects, in addition to waterstress effects, were evident. In vitro digestible dry matter (IVDDM) in stem bases increased with CWSI (r2 = 0.78), but leaf IVDDM was not significantly related to CWSI. Crude protein (CP) concentration in stem bases increased with CWSI (r2 = 0.86), whereas leaf CP concentration declined quadratically with increasing CWSI (r2 = 0.51). Total‐herbage CP concentration was not significantly related to CWSI. Neutral‐detergent fiber concentration in stem bases, leaves, and total herbage declined with increasing CWSI (r2 = 0.89, 0.75, and 0.69, respectively). Thus, models based solely on plant quality‐CWSI relationships may not be adequate for predictive purposes because, often, year effects were not removed or coefficients of determination were low.
Daylength and Temperature Effects on Emergence and Early Growth of Sericea Lespedeza
Authors: Mosjidis J. A. 
Published: July 2010

AbstractPoor emergence and seedling growth of sericea lespedeza [Lespedeza cuneata (Dumont de Courset) G. Don.] may be related to the climatic conditions under which it is established in the southern USA. A growth chamber study was undertaken to measure the effect of temperature on seedling emergence and the influence of temperature and daylength on early growth of several sericea lespedeza genotypes. Emergence was reduced by about 20% with each reduction of 3 °C in day /night temperature within the range of temperatures used. Height, shoot dry weight, leaf dry weight, and stem dry weight of all genotypes tested were very sensitive to both daylength and temperature. Increases in temperature and day length above the lowest temperature combination (18/14 °C) and the shortest daylength (11 h) brought about large increases in height, shoot dry weight, leaf dry weight, and stem dry weight of all genotypes. Screening sericea genotypes for seedling growth should be done at 26/22 °C or 30/26 °C (day/night) and 13 or 15 h of daylength. Further screening of sericea germplasm for emergence and growth underlow temperature and for day‐neutral genotypes may lead to cultivars with more vigorous seedlings under short day conditions.
Long‐Term Field Research on Water and Environmental Quality
Authors: Menzel R. G. 
Published: July 2010

AbstractMaintaining the quality of soil, water, and air presently has a high national priority, and is particularly important for agriculture. The deterioration of environmental quality, in most respects, has proceeded almost imperceptibly. Long‐term research is required to study effects that change slowly with time, such as contamination of groundwater, or that depend upon infrequent weather events, such as water erosion of soil. Much environmental quality research involves long‐term measurements of runoff and soil erosion because these are the dominant mechanisms for transporting nutrients and pesticides to rivers and lakes. Water and environmental quality studies are being made at sites ranging from small field plots to large watersheds and experimental lakes. Effects of acid rain are being studied mainly at watershed and lake sites. There has been little long‐term groundwater quality research on agricultural areas, but a major investigation of nitrate and pesticide movement is getting under way. Long‐term field research is essential to confirm and refine the predictions derived from environmental models.
Evaluating Nitrogen Fertilizer Rate and Timing for Meadowfoam Seed and Dry Matter Production
Authors: Jolliff Gary D. , Seddigh Majid 
Published: July 2010

AbstractPrevious reports on N fertilization effects on meadowfoam (Limnanthes alba Hartw. ex Benth.) seed yield are inconsistent. This study was conducted to determine whether N fertilizer application rate and timing could be manipulated to increase seed yield in ‘Mermaid.’ Field experiments were conducted during the 1982–1983 and 1984–1985 seasons on a Woodburn silt loam (fine‐silty, mixed, mesic Aquultic Argixeroll) to evaluate the influence of twelve combinations of N rate and timing on Mermaid dry matter production and seed yield. Treatments included 50, 100, and 200 kg N ha−1 applied in fall, winter, spring, and split fall/spring timings. Except for the 50 and 100 kg N ha−1 applied in the fall of 1984, seed yields for all N treatments were greater than the control. Application rate and timing interactions on dry matter production, seed yield, and harvest index were not significant in either growing season. Averaged over rates, fall application resulted in significantly lower seed yield and total dry matter than the other timing treatments, presumably because of N loss through leaching. The effects of application rates above 50 kg N ha−1 on dry matter production and seed yield varied between years. The data suggest that 50 kg N ha−1 applied in late winter or early spring increases meadowfoam seed yield. Under climatic conditions such as during the 1984–1985 season when lodging was low, higher rates of N might be beneficial. However, application of more than 50 kg N ha−1 in spring could reduce seed yield if the climatic conditions are conducive to lodging.
Influence of Ethephon on Lowest Pod Height and Yield of Soybean
Authors: Grabau L. J. , Pearce R. C. , Konsler J. V. 
Published: July 2010

AbstractEthephon [2‐(chloroethyl) phosphonic acid] has improved lodging resistance of several crops, mainly by reducing plant height. Our objective was to determine if ethephon could reduce plant height of soybean [Glycine max (L.) Merr.] without reducing lowest pod height (LPH), which would increase the potential for stubble harvest losses. Maturity group IV soybean cultivars Ripley (short) and Southern States 443 (tall) were planted in both full season and late‐planted cropping systems in 1987 and 1988 on a Maury silt loam (fine, mixed, mesic Typic Paleudalfs) near Lexington, KY. Ethephon was applied at 280 g a.i. ha−1 at growth stages V4, V6, or V4 and V6. All three ethephon treatments reduced plant height to a similar degree. No ethephon effect on lodging was detected, since lodging pressure was minimal. Ethephon did not reduce LPH, and thus had no effect on stubble harvest losses. In addition, ethephon did not influence grain yield. Ethephon successfully reduced plant height without increasing stubble harvest losses. No conclusion on the effect of ethephon on lodging resistance of soybean can be drawn from this research.
Nitrogen Use by Northern‐Adapted Barley Genotypes Under No‐Till
Authors: Tillman B. A. , Pan W. L. , Ullrich S. E. 
Published: July 2010

AbstractNo‐till planting can restrict the growth and productivity of spring grains in the U.S. Pacific Northwest. Cooler soil temperatures, compared to conventional tillage, may contribute to lower productivity. Therefore, genotypes bred in cold climates may better adapt to notill management. Eleven spring barley (Hordeum vulgare L.) genotypes were evaluated for N content and dry matter accumulation under direct drilling at 45 and 90 kg N ha−1. These genotypes originated in the Pacific Northwest (PNW) or the Northern European (Nordic) countries Denmark, Finland, and Sweden. The Nordic genotypes were developed under cooler, wetter soil conditions than the PNW genotypes, and were therefore predicted to be better adapted to no‐till management. Barley was drilled into stubble of spring cereals in a Palouse silt loam (fine‐silty, mixed mesic Pachic Ultic Haploxeroll). The Finnish genotypes, HJA Potra, HJA 80201, and HJA 78003, generally had greater above‐ground dry matter and N content than the domestic genotypes prior to anthesis. These differences were not sustained through rain filling, however, and PNW genotypes accumulated more N and dry matter per unit area by maturity. Steptoe was the only genotype that consistently absorbed N during grain filling, while many genotypes exhibited net N losses. Nitrogen remobilization and N harvest index tended to be greater in 6‐row genotypes compared to 2‐row genotypes. The PNW genotypes generally outyielded the Nordic genotypes with the exception of ‘Nordal’. Nevertheless, if the physiological traits of the Nurdic genotypes associated with efficient N uptake during cold soil conditions could be incorporated into an existing PNW genotype, improved N use efficiency may be obtainable.
Response of Internal Tissue Water Balance of Peanut to Soil Water
Authors: Erickson P. I. , Ketring D. L. , Stone J. F. 
Published: July 2010

AbstractEfficient water application for crop productivity requires knowledge of the plant/soil water balance. The objectives of this research were to determine how peanut (Arachis hypogaea L.) leaf water content responds to soil water content and to examine the soil water content‐ΨS relationship for predicting limiting levels of soil water relative to crop water status in the field. Few field data describing peanut internal water balance responses to soil water are available. In the present study, available soil water content is defined as water content minus water content at −1.5 MPa divided by water content at −0.01 MPa minus water content at −1.5 MPa. This approach. normalizes water content to the fraction available. It is analogous to leaf relative water content (LRWC) and is expressed as soil relative water content (SRWC). The objectives of this research were to: (i) define the relationship between SRWC and LRWC of peanut grown under rainfed and irrigated conditions, and (ii) use SRWC to predict limiting levels of soil water relative to crop water status. Plants were grown on a Teller loam soil (fine, mixed, thermic Udic Argiustoll). Weekly midday (1130 to 1300 apparent solar time) measurements of LRWC were made between 40 and 100 d after planting (DAP). Weekly SRWC values were interpolated to correspond to LRWC measurement days. Above 50% SRWC, the mean LRWC was about 85%, and appeared to be affected more by evaporative demand than by SRWC. Below 50% SRWC, LRWC was highly correlated with SRWC. The predicted SRWC when turgor pressure potentials approached zero was about 45%. This SRWC threshold occurred under rainfed conditions in the 3 yr studied at 59, 56, and 64 DAP during flowering and pod formation. It is concluded that the SRWC vs. soil water pressure potential curve of Teller soil may be useful for predicting limiting levels of soil water for peanut and that limiting levels of soil water may occur well above the classically defined lower limit of soil water availability.
Measuring Water Infiltration Rates of Sports Turf Areas
Authors: Taylor D. H. , Williams C. F. , Nelson S. D. 
Published: July 2010

AbstractMeasuring the rate of decline of ponded water in rings is commonly used to determine water infiltration rates on turfgrass sites. Recently rings smaller than 30 cm in diameter have been marketed and used. This research examined the utility of 15‐ and 20‐cm diam. rings used as single or as double rings as well as 30‐ and 50‐cm diam. double rings for measuring water infiltration rate into golf greens and athletic fields. Results indicated that infiltration rates measured by any ring, including the 30‐ and 50‐cm diam. double ring, varied widely on a single golf green or athletic field. Infiltration rates measured with smaller rings used either as single or as double rings did not always correspond well with infiltration rates measured by the larger double rings. Infiltration rates measured with ponded water in single or double rings on sports turf areas should be viewed only as rough estimates and results should be used with caution.
Agronomic Performance of Winter versus Spring Wheat
Authors: Entz M. H. , Fowler D. B. 
Published: July 2010

AbstractRecent advances in crop management have enabled the production of winter wheat (Triticum uestivum L.) in most of the Canadian prairies. The agronomic performance of dominant hard red winter and highq‐uality hard red spring wheat cultivars was compared in semiarid and dry subhumid regions of Saskatchewan. In 15 trials, winter wheat (WW) outyielded spring wheat (SW) by an average 36%, and in three trials, ‘Norstar’ WW yielded 26% higher than the high‐yielding semidwarf SW, ‘HY 320.’ Protein yield was higher for WW in two of 15 trials and protein concentration was always higher for SW. Higher grain yield of WW was attributed mainly to the production of a higher kernel number per square meter (KNO). Crop development rate, aerial dry matter production, evapotranspiration (ET), and water use efficiency (WUE), were measured for Norstar WW and ‘Katepwa’ SW in six trials grown between 1986 and 1988. The period between Zadoks growth stage (ZGS) 21 and 65 was 4 to 14 d longer for Norstar than for Katepwa. Average daily air temperature between ZGS 21 and 65 was 2.6°C higher for Katepwa, and daily air temperature during this period was negatively correlated with KNO in both cultivars. Early season dry matter production was highest for Norstar. These early season cultivar differences gradually disappeared and, with the exception of two trials, total dry matter was similar by crop maturity. Harvest index was significantly higher for Norstar in five of six trials. Seasonal ET patterns were similar for Norstar and Katepwa, except in three of six trials where ET in early May was significantly higher for the WW cultivar. The WUE for dry matter production, grain yield and grain protein yield was consistently higher for Norstar.
Nodulation, Dinitrogen Fixation, and Yield Improvement in Second‐Crop Soybean Cover‐Inoculated with Bradyrhizobium japonicum
Authors: Ciafardini G. , Lombardo G. M. 
Published: July 2010

AbstractWhen soybean [Glycine max (L.) Merr.) is grown in soil containing few Bradyrhizobium japonicum (Kirch.) Jordon, the limited mobility of the symbiont results in the formation of a small number of nodules distributed mainly on the primary root of the plant near the inoculation point. The authors conducted a 3‐yr study aimed at increasing nodulation and N2 fixation in ‘Hodgson’ soybean as a second crop, by cover inoculating B. japonicum on the soil with irrigation water at the time of sowing or at the three‐node (V3) stage. Inoculation treatments were: (i) seed inoculation; (ii) cover inoculation at sowing; (iii) seed inoculation plus cover inoculation at sowing; (iv) cover inoculation at the V3 stage; (v) seed inoculation plus cover inoculation at the V3 stage; (vi) uninoculated control. The seed plus cover inoculation at sowing or the V3 stage produced, on the whole, the greatest nodulation, 1.4 to 2.4 times that for seed inoculation alone. The addition of cover inoculation at sowing increased seed yield by 50 g m−2 in 1985 and 90 g m−2 in 1986, regardless of whether the cover inoculation was performed at sowing or the V3 stage. In 1988, a year in which the soybean was sown about 1 mo later than in the previous years and subjected to higher temperatures, seed and cover inoculation increased N2 fixation and plant‐N concentration, but not yield.
Small‐Plot Windrower
Authors: Ehrensing D. T. , Crane J. M. , Bolton F. E. 
Published: July 2010

AbstractAlthough many crops are commonly field dried in windrows, research has often been limited by the lack of adequate equipment for small‐plot windrowing. A research scale windrowing machine was constructed that closely imitates commercial practice. The machine was used on a number of crops in 1989.