bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen Fertilizer Requirements of Irrigated Safflower in the Northern Great Plains1
Authors: Haby V. A. , Black A. L. , Bergman J. W. , Larson R. A. 
Published: July 2010

AbstractAlternaria carthami‐resistant safflower varieties have been developed for irrigated production in the Northern Great Plains. Data were needed to determine the irrigation and fertilizer N requirements of this crop. Seven rates of N fertilizer in 45 kg/ha increments to 270 kg/ha of silty clay soil types, and two rates of K, 0 and 45 kg/ha, were applied as subplots in a split‐plot, randomized irrigation by N rate study in field research on safflower, Carthamus tinctorius, ‘Sidwill.’ Irrigation treatments were applied at specific plant growth stages. At only one of three sites was seed yield increased by irrigation. In that instance irrigation at early bud stage produced maximum seed yield. Pre‐irrigation and a water table at a depth of 1.5 m at Sites H7 and H8, and above normal precipitation at Site H8, may have limited yield response to irrigation. Test weight of seed was lowered and N, P, and K concentrations in safflower residue were increased by irrigation.Yield and protein content of the seed increased with increasing fertilizer N rates. The 270 kg/ha fertilizer N rate decreased seed oil content on the site with the highest residual and mineralizable soil N. Test weight response to N rates varied among sites. Increasing rates of N fertilizer increased the N and K but decreased the P concentrations in the safflower stubble. Statistically significant optimum yields were obtained when the sum of residual NO3‐N in the 0 to 1.22 m soil depth, mineralizable N from organic matter and previous crop residue, and fertilizer N equaled 274 kg/ha.
Quantitative Separation of Roots from Compacted Soil Profiles by the Hydropneumatic Elutriation System1
Authors: Smucker A. J. M. , McBurney S. L. , Srivastava A. K. 
Published: July 2010

AbstractKnowledge of plant root responses to both favorable and unfavorable soil conditions is fundamental to our understanding of the complex root soil interface. One of the greatest hindrances to the frequent measurements of the morphological and physiological responses of plant roots to soil environmental conditions has been the absence of an inexpensive method for quantitatively separating the soil from roots and other biological materials.The objectives of this study were to develop an inexpensive and quantitative method for separating roots from soils of field and greenhouse experiments and to determine the influence of soil type, pretreatment and plant type on the efficiency of separation.A mechanized system which separated roots from soil materials was constructed which combines the kinetic energy of pressurized spray jets and the low energy of air flotation. Root elutriation systems were fabricated from commercially available components at a cost of less than $25 per unit excluding labor. A manifold of these units was assembled to increase operator efficiency. Quantitative separation of roots is achieved by a closed system of mechanical separations using water and air to isolate and deposit roots on a submerged sieve. Washing times range from 3 to 10 min and is a function of soil texture, plant species, concentration of the dispersing agent and soaking time. Utilizing a manifold of nine separation units and two personnel, an average of 60 samples could be separated per hour. Water consumption per unit ranges from 2.1 to 3.4 liters per minute. This method, in combination with a powered soil sampler, appears to provide a rapid, quantitative and inexpensive approach for measuring plant root responses to soil biological, chemical, and physical stresses.
Placement of Nitrogen Fertilizers for No‐Till and Conventional Till Corn1
Authors: Mengel D. B. , Nelson D. W. , Huber D. M. 
Published: July 2010

AbstractHigh rates of N loss have been observed from N fertilizers applied directly on the surface in no‐till corn (Zea mays L.) production systems. Field experiments were conducted at four locations over a three‐year period to determine what effects N source and N placement had on N losses in both no‐till and conventional till corn production systems. Soils used were: Stoy loam, an Aquic Hapludalf; Clermont silt loam, a Typic Ochraqualf; Avonberg silt loam, an Aeric Fragiaqualf; Chalmers silty clay loam, a Typic Argiaquoll; and Lyles fine sandy loam, a Typic Haplaquoll. Nitrogen sources used were anhydrous ammonia (NH3), urea‐ammonium nitrate solutions (UAN), solid urea and solid ammonium nitrate (NH4NO3). Placement variables used were injection of NH3 and UAN 20 cm below the soil surface and broadcasting UAN, urea and NH4NO3 on the soil surface with no incorporation. Nitrogen rates used were 0 and 165 kg N/ha.Injecting NH3, or UAN below the surface resulted in consistently higher corn grain yields than applying UAN, NH4NO3 or urea directly on the soil‐residue surface. Percent N in leaf and grain also reflected an increase in N use efficiency with subsurface N placement. Percent N in leaf was significantly higher where NH3 or UAN were injected as compared to UAN or urea surface applied.
Effect of Nitrapyrin on N Response of Corn on Sandy Soils1
Authors: Chancy H. F. , Kamprath E. J. 
Published: July 2010

AbstractPreplant N fertilizer applications on sandy Coastal Plain soils are often less efficient than sidedress N applications due to leaching of NO−3 from the rhizosphere. Preplant‐incorporated broadcast applications of ammoniacal N fertilizers containing the nitrification inhibitor nitrapyrin [2‐chloro‐6(trichloromethyl)pyridine] should increase utilization of the exchange capacity of sandy soils to retain NH+4 and increase preplant N fertilizer efficiency. The effects of N rate, N source, and nitrapyrin on inorganic soil N form, soil N content, and corn (Zea mays L.) growth were investigated in 1977 on a Marlboro sand (Typic Paleudult) and a Varina loamy sand (Plinthic Paleudult) and in 1978 on a Wagram sand (Arenic Paleudult). Nitrogen treatments consisted of a zero‐N check, preplant broadcast applications of 56, 112, 168, and 224 kg N/ha as urea, 112 kg N/ha as NaNO3, and 112 kg N/ha as urea plus 1.12 kg nitrapyrin/ha dissolved in water.Soil N measurements at 34, 40, and 48 days after N treatment application on the Marlboro, Varina and Wagram soils, respectively, showed that nitrification was suppressed by nitrapyrin. The lack of significant differences in inorganic soil N contents in the 0 to 15 cm depth among 112 kg N/ha supplied as urea with and without nitrapyrin and NaNO3 indicated that little leaching occurred in 1977. Leaching conditions in 1978 resulted in large losses of inorganic N from the rooting zone; however, when nitrapyrin was added with urea, losses of N were significantly reduced. High N rates from urea decreased the pH in all soils except when nitrapyrin was included. In 1977, inclusion of nitrapyrin with urea had little effect on leaf N, grain yields, plant N accumulation or N fertilizer recovery due to small losses of soil inorganic N. However, in 1978 when leaching conditions occurred, nitrapyrin with urea decreased soil N losses, significantly increased leaf N concentration, grain yields, plant N accumulation and N fertilizer recovery.
Reducing Moisture‐Induced Error Associated with Measuring Forage Quality Using Near Infrared Reflectance1
Authors: Fales S. L. , Cummins D. G. 
Published: July 2010

AbstractSample moisture may impair accuracy in predicting forage quality based on near infrared‐reflectance (NIR), but the literature contains little specific information on the topic. The purpose of this study was to determine the extent to which moisture interferes with the ability of NIR to predict acid detergent fiber (ADF) in silage‐type sorghums [Sorghum bicolor (L.) Moench.]. Comparisons were made between laboratory and predicted ADF on samples that were oven‐dry or had been stored at 43% (low), 63% (medium), and 100% (high) relative humidities. Results showed no significant differences between laboratory and predicted ADF for samples that were dry or had been stored under conditions of low humidity. However, when samples were stored under medium or high relative humidities, a significant (P ≤ 0.05) over‐estimation of ADF resulted. Increased sample moisture lowered predictability, since the standard error of estimate increased from 1.27 and 1.18 for dry and low moisture samples, to 2.28 and 4.15 for medium, and high moisture samples, respectively. Consistently repeatable ADF values were obtained when calibrations and NIR analyses were conducted on oven‐dry material, which emphasizes that NIR analyses should be conducted only on recently oven‐dried material that has been stored in a desiccator.
Response of Tomatoes to N and Water Applied Via a Trickle Irrigation System. I. Nitrogen1
Authors: Bar‐Yosef B. , Sagiv B. 
Published: July 2010

AbstractDespite the widespread use of combined trickle irrigation and fertilization (fertigation) in arid zones, little is known about the efficiency of point source fertigation in general, and about drip irrigation management of tomatoes in particular. The objective of the present work was to study the response of tomato plants grown under trickle irrigation in sand dunes to total and daily N application rates, and to concentrations of N in the irrigation water and in the soil solutions at various physiological stages of growth.The experiments, carried out at three different locations in Israel, included combinations of several daily N and water application rates and two irrigation intervals.The total yield (Y, in metric tons/ha) was related to total N application rate (X, in kg/ha) by the regression equation Y = 0.0714X + 35.83. The overall N uptake in the high‐yield treatments was about 30% of the N applied. The low efficiency is attributed partly to excessive N application 140 days from seeding, when the daily demand for N (FN) was small. To obtain the optimum FN values at about 70 and 140 days after seeding (5.2 and 2.2 kg N ha−1day−1), NO3‐N concentration in the soil solution should be 200 and 100 ppm, respectively.
Effects of Nitrogen Nutrition on the Growth, Yield, and Reflectance Characteristics of Corn Canopies1
Authors: Walburg G. , Bauer M. E. , Daughtry C. S. T. , Housley T. L. 
Published: July 2010

AbstractRemote sensing offers the potential to determine rapidly the physiological condition of crops over large areas. To realize this potential, information is needed on the seasonal reflectance patterns of healthy and stressed crop canopies. A field experiment was conducted in which spectral and agronomic measurements were collected from corn (Zea mays L.) canopies grown under four N treatment levels (0, 67, 134, and 202 kg/ha) on a Raub silt loam (Aquic Argiudoll) soil. Data were collected at the Purdue Agronomy Farm, West Lafayette, Ind., on 11 dates during 1978 and 12 dates during 1979. Reflected radiation of 0.4 to 2.4 µm wavelength was measured with an Exotech 20C spectroradiometer and used to compute a reflectance factor. Agronomic data collected coincidently included biomass, leaf area index, plant height, crop development stage, percent soil cover, and surface soil moisture percent. Data were analyzed to determine: 1) the relationship between the spectral and agronomic characteristics of the canopies and 2) the spectral differences and separability of the four treatments.Nitrogen treatment effects were seen across the entire wavelength interval measured. Red reflectance was increased and near infrared reflectance was decreased from N‐deprived canopies. Spectral differences between treatments were seen throughout each growing season. The near infraredred reflectance ratio (0.76 to 0.90 µm)/(0.63 to 0.69 pm) differed more between treatments than single band reflectance measures. Variations in canopy reflectance due to wetting and drying of soils were reduced by the use of the near infrared/red reflectance ratio.The spectra of the four N treatments were significantly different (Duncan's multiple range test, P = 0.05) on August dates. Early and late in the season only two spectral classes were resolved. Of the spectral variables examined, the near infraredhed reflectance ratio most effectively separated the treatments. Discrimination results for both years were similar in spite of larger treatment differences in 1979 than in 1978. Differences in spectral response between treatments were attributable to varying soil cover, leaf area index, and leaf pigmentation values, all of which changed with N treatment. The results further confirm the potential of remote sensing for monitoring the growth and development of crops.
Growth and N Fixation of Some Tropical Forage Legumes as Influenced by Solar Radiation Regimes1
Authors: Eriksen F. I. , Whitney A. S. 
Published: July 2010

AbstractDecreased solar radiation due to cloud cover or shading by plantation crops or associated grass can severely limit the production of tropical forage legumes. We therefore evaluated the response of six legumes (three replicated and three not replicated) to four radiation regimes (100, 70,45, and 27% of unshaded solar radiation, hereafter termed “full sun”) with polypropylene netting in the field.The three replicated legumes had significant yield reductions at 27% full sun, with intermediate reductions at 70 and 45%. Dry matter (DM) yields at full sun [metric tons (mt) ha,−1yr−1 and proportional yields at 27%] were: Desmodium intortum cv. Greenleaf (20.0, 46%); Centrosema pubescens ‘centro’ (13.7, 44%); and Macroptilium atropurpureum cv. Siratro (12.9, 20%). Greenleaf was relatively tolerantof moderate shading; proportional yields at 70 and 45% of full sun were 93 and 75%, respectively. Centro and Siratro yields declined linearly as shortwave radiation (hereafter termed “radiation”) decreased, but Siratro yields declined significantly more than centro. Marked seasonal differences were noted in the response of the legumes to shade, and this was attributed to differences in the ability of the legumes to utilize solar radiation during periods of cool temperatures. The three non‐replicated legumes were evaluated similarly, except that yields were adjusted for replication effects. Dry matter yields and proportional yields at 27% full sun were: Leucaena Ieucocephala cv. Hawaiian Giant (23.5, 40%); Stylosanthes guianensis cv. Schofield (17.0, 17%); and Desmodium canum ‘kaimi clover’ (12.2, 32%). Hawaiian Giant and Greenleaf yielded similarly at 45 and 27% full sun. Kaimi clover DM yield tended to be slightly higher (13.8) at 70% full sun, but thereafter yields declined linearly with reduced radiation. Schofield stylo was the most sensitive to shading.Dry matter and N concentrations were not significantly elevated by reduced radiation or cool weather except that N increased during the cool season. Concentrations of N differed among species being highest for centro and Hawaiian Giant (3.4%) and lowest for kaimi clover (2.6%). Total N yields were associated with DM yields. Nitrogen yields (kg N ha−1yr−1) of replicated legumes at full sun and proportional yields at 27% full sun were: Greenleaf (540, 45%), centro (461,44%), and Siratro (362,27%); and for the non‐replicated legumes, Hawaiian Giant (751,38%), Schofield (496, 18%), and kaimi clover [340 (361 at 70% full sun), 38%]. Acetylene reduction rates by nodules in soil cores were highly correlated with radiation regimes (r = 0.92‐0.995; except for centro, r = 0.71.) Correlation of acetylene reduction rates with DM yields ranged from 0.80 to 0.996.The higher yielding legumes, Greenleaf, centro, and Hawaiian Giant (plus kaimi clover for ≈70 % full sun only) appear well‐suited for areas of low solar radiation because they have relatively constant concentrations of DM and N and fixed significant quantities of N even under dense shade.
Effects of Cultural Practices on Agronomic and Reflectance Characteristics of Soybean Canopies1
Authors: Kollenkark J. C. , Daughtry C. S. T. , Bauer M. E. , Housley T. L. 
Published: July 2010

AbstractUnderstanding the relationship between the reflectance measured and the various cultural practices used in today's soybean production is key for further development and use of remote sensing as a tool for crop monitoring. Field experiments were conducted at the Purdue Agronomy Farm in West Lafayette, Ind. in 1978 and 1979 to study the reflectance factor (RF) of soybean (Glycine max L. Merr.) canopies as affected by differences in row width, population, planting date, cultivar, and soil type (Typic Argiaquoll and Typic Hapludulf). Reflectance factor (RF) data were acquired with a Landsat‐band radiometer (Exotech 100), which is a four band radiometer with a 15‐degree field of view that measures radiance in the following wavelength regions: 0.5–0.6, 0.6–0.7, 0.7–0.8, and 0.8–1.1 µm. Agronomic measurements included plant height, leaf area index, development stage, total fresh and dry biomass, and percent soil cover.Row width, planting date, and cultivar influenced the percent soil cover, leaf area index, biomass, and development stage of the soybean canopies. Changes in these agronomic variables were manifested in the canopy reflectance. Soil color and moisture were important factors influencing RF in single Landsat bands; however, the near infrared/ red reflectance ratio and the greenness transformation were less sensitive than the single bands to changes in soil background. Variations in spectral responses are strongly associated with planting date during early to mid‐season, with the row width during mid‐season to near maturity, and with cultivar at maturity. This information should be useful in applications of remote sensing for identifying crops and estimating crop condition and yields.
Soybean Response to Different Planting Patterns and Dates1,3
Authors: Beatty K. D. , Eldridge I. L. , Simpson A. M. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] response to narrow rows (less than 50 cm apart) has been inconsistent in the southern United States. However, a more positive response has been documented in the North Central USA. Lack of suitable herbicides for controlling weeds in narrow row soybeans in the South has slowed acceptance of this practice. Development of more effective herbicides has made narrow row soybean production feasible.Earlier planting dates can take advantage of favorable soil moisture conditions. Soybean plantings following wheat [Triticitm aestivum (L.) em. Thell.] harvest often do not close the crop canopy between rows before flowering when planted in rows 92 cm or more apart. Experiments were conducted in 1978 and 1979 (Vertic Haplaquept soils) to determine the effects of row spacings, broadcast seeding, planting dates, and soybean cultivars on yield and other plant characters.Seed yield was affected by row spacing or methods, planting dates, years, and planting dates x years. Cultivars and the cultivar x planting method interaction were not significant for yield but none of the cultivars used in the study had been selected for narrow row conditions. The 18 and 48 cm row widths produced 15% higher seed yields than the conventional 96 cm row spacing. Mean yields across row spacings (including broadcast planting) and cultivars for the 15 July planting date were less than 50% of the April or May plantings. The cultivar x planting date interaction was large for percent seed protein because the late planted Forrest cultivar was significantly lower in percent protein compared to earlier planted Forrest. Pods per plant were significantly associated with yield in 1979 but not in 1978.
Simazine Formulation Treatments on Control of Winter Weeds in Bermudagrass Turf1
Authors: Johnson B. J. 
Published: July 2010

AbstractExpanding choices of herbicides for consistent control of winter annual weeds are needed in turfgrass throughout the Southeast. Therefore, an experiment was conducted on Cecil sandy loam (Typic Hapludult) to determine effects of formulations, rates, and dates of simazine [2‐chloro‐4, 6‐bis(ethylamino)‐s‐triazine] treatments for the control of winter annual weeds in bermudagrass [Cynodon dactylon (L.) Pers.] turf.The most consistent control of winter weeds from preemergence treatments applied in September occurred from the 1.8 and 2.2 kg/ha granule rates and 2.2 kg/ha wettable powder treatment. Slurry treatments applied in September did not effectively control parsleypiert (Alchemilla microcarpa Boissier Reuter) or corn speedwell (Veronica arvensis L.). Postemergence February treatments generally controlled parsley‐piert, corn speedwell, hopclover (Trifolium agrarium L.), and annual bluegrass (Poa annua L.) effectively (80% or higher) regardless of rates and formulations. An exception occurred with granular formulation for hop clover as the control from the 0.9 kg/ha rate was not as good as when treated with other formulations at the same rate. February granular treatments did not satisfactorily control spur weed (Soliva spp), whereas, at least 70% of weeds were controlled with 1.8 kg/ha or higher rates of wettable powder and slurry treatments. However, spur weed control was improved significantly from repeated September and February treatments when compared with single treatments at selected rates. None of the simazine treatments delayed early growth of bermudagrass in the spring regardless of formulation, rates, or dates of treatment.
Nitrogen Source Effect on Nitrate and Ammonium Leaching and Runoff Losses from Greens1
Authors: Brown K. W. , Thomas J. C. , Duble R. L. 
Published: July 2010

AbstractThe use of sandy rooting media with rapid infiltration rates in the construction of golf greens provides the potential for N pollution of nearby water supplies. This study was designed to measure the effects of different N sources on NO−3 and NH+4 concentrations in leachate and runoff from golf greens constructed with various rooting media.Individual golf greens with USGA‐type profiles were constructed in the field with upper 30 cm layers consisting of sand‐peat, sandsoil‐peat and sandy loam soil mixtures. All profiles were equipped with subsurface tile drains over a plastic sheet and were treated sequentially with the following N fertilizers: NH4NO4, ureaformaldehyde, 12‐12‐12, Milorganite, and IBDU. Leachate and runoff were collected and analyzed for NO−3 and NH+4. Nitrate concentrations in leachate from sand, mixed, and soil greens fertilized with quick release materials ranged from 45 to 326, 8 to 314 and 8 to 170 mg liter−1, respectively and remained in this range for a 3‐week period. Runoff concentrations from the greens constructed of sandy loam soil exceeded 30 mg liter−1. No runoff was collected from sand or mixed greens.Nitrate N losses from various sources were in the order of NH4NO3 > 12‐12‐12 > Milorganite > Isobutylenediurea (IBDU) > Ureaformaldehyde. lsobutylenediurea provided a very uniform release rate. Milorganite had a 25 to 30 day delay before NO−3 appeared in the leachate. Soluble sources, NH4NO3, and 12‐12‐12 exhibited leaching within 5 days after application. It appears that regular moderate applications of slow release N sources would provide minimum NO−3 loss while supplying a continuous N supply.Ammonium losses ranked from greatest to smallest were NH4NO3 > Ureaformaldehyde > Milorganite > 12‐12‐12 > IBDU. Ammonium losses contributed very little to the total N losses from golf greens. Highest total N loss was 23% of the applied N.