bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stress Measurement Using Foliage Temperatures1
Authors: Walker G. K. , Hatfield J. L. 
Published: July 2010

AbstractThe total (stomatal and aerodynamic) conductance for water vapor of a crop (gv) reflects the rate of crop production. Determination of gv should therefore be valuable in predicting crop yield. With an energy balance approach to crop stress assessment, foliage‐air temperature differences (Tf — Ta) may provide a means of determining gv. This study was conducted to model the response of Tf — Ta to environmental parameters and conductances, and then, in a field experiment with kidney beans (Phaseolus vulgaris L.) grown under two radiation regimes, to determine gv using measured Tf — Ta values, and to relate this to crop yields. Kidney beans (‘Red Kidney’) were grown on deep Yolo clay loam (Typic Xerorthent) at Davis, Calif., under normal irradiance and with irradiance reduced by 50%. Different stress levels (different gv) were established by varying time and frequency of irrigation. Foliage temperatures (corrected for emissivity and sky radiation), net radiation and wet and dry bulb temperatures were recorded daily at ½ to 1 h after solar noon through most of the growing season. Seed yields were measured at the end of the season. The energy balance model and field data showed that Tf — Ta is sensitive to air saturation deficit (0.16°C mb−1) and to net radiation (0.5°C/100 W m−2). Using an energy balance scheme, calculations of gv were made from field data for the seed filling period. Relative yields estimated as gv/gmax, with gvmax determined from well‐watered plots, agreed well with relative seed yields (r = 0.75). Major Tf — Ta responses to saturation deficit and net radiation showed that Tf‐based crop stress estimates will not relate well to crop production unless these environmental parameters are accounted for, or unless they vary little between times of measurement. By using the energy balance, Tf — Ta measurements can be related explicitly to gv and, thereby, to crop production.
Nitrogen Distribution in Roots and Tops of Winter Wheat1
Authors: Smith T. L. , Peterson G. A. , Sander D. H. 
Published: July 2010

AbstractThe hypothesis has been proposed that the observed N losses from the aboveground parts of wheat (Triticum aestivum L.) near maturity might be explained by N redistribution to roots during the late grainfill period. This experiment was designed to test this hypothesis. Plant response to four N levels using a modified Hoagland's solution was studied in gravel culture. Roots and tops were harvested 12 times during the growth cycle and analyzed for N content. Nitrogen uptake patterns for roots and shoots were similar. At about 50 days after jointing (Feeke's Stage = 11.2) both roots and shoots began to lose N, while head N increased from anthesis to maturity. Gains in head N exceeded the amounts lost from the roots and shoots. So, N uptake from the culture solution continued through maturity. The hypothesis that N is redistributed to the roots near maturity in winter wheat was rejected. Roots were actually a source of N for translocation to the grain, as were aboveground stems and leaves.
Slope Position and Grain Yield of Soft White Winter Wheat1
Authors: Ciha A. J. 
Published: July 2010

AbstractWinter wheat (Triticum aestivumL.) producers in the Palouse Region of southeastern Washington generally seed one wheat cultivar over a wide range of environmental conditions formed by the rolling topography of the area. A 2‐year field study was conducted during 1977–1979 growing seasons on five slope positions across a Palouse silt loam (fine‐silty mixed, mesic pachic Ultic Haploxerolls), a Naff silt loam (fine‐silty, mixed, mesic Ultic Agrixerolls), and a Snow silt loam (fine‐silty, mixed, mesic Cumulic Haploxerolls) to examine the influence of slope position on grain yield and yield components of 12 soft white winter wheat cultivars. Slope position and cultivar significantly influenced grain yield while only cultivar significantly influenced test weight. There were significant cultivar ✕ slope position and slope position ✕ year interactions for grain yield, test weight, and culm height. Differences in mean grain yield for an individual cultivar ranged from 0.45 to 1.90 Mg/ha when compared across slope positions. Yield components were examined during the 1977–1978 growing season and were found to be significantly influenced by slope position and cultivar. Spikelets/spike and 100‐seed weight were the only yield components to show a significant cultivar ✕ slope position interaction. These findings indicate the need to more clearly define where soft white winter wheat cultivars are best adapted to meet specific environmental and topography conditions.
Snap Bean Plant Responses to Nitrogen Fertilization1
Authors: Peck N. H. , MacDonald G. E. 
Published: July 2010

AbstractNitrogen fertilization may affect vegetative growth as well as yield and quality of pods of snap bean [Phaseolus vulgaris(L.) var. humilis] plants. A study was conducted to determine the effect of N fertilization on vegetative growth, N partitioning in the plants and production of pods on snap bean plants. Snap bean plants, Bush Blue Lake‐47, were grown under field conditions with N from ammonium nitrate at rates of 0, 4, 8, and 12 g m−2placed in a band 5 cm to the side and 5 cm below the depth of the seeds at planting time on 10 June 1981 in a Lima silt loam (fine‐loamy, mixed, mesic Glossoboric Hapludalf), a productive soil derived from calcareous glacial till. Rows were 50 cm apart with 22 productive plants m−1of row (44 plants m−2). The fresh weight, dry weight, total N and nitrate N were determined in different parts of the plants at the seedling, bloom, and pod stages. Yield and quality determinations were made on the pods at 10 and 13 August harvests. Fertilizer N decreased growth of the plants in the seedling stage but not by the pod stage. Fertilizer N reduced the number of rhizobium nodules on the roots. At the pod stage, total N was 15.7 g m−2in plants grown with residual available soil N but without fertilizer N, while total N was 19.5 g m−2in plants grown with residual soil N plus fertilizer N at 12 g m−2. Fertilizer N at 4 to 8 g m−2produced the optimum quality and yield of snap bean pods for processing.
Yield and Quality of ‘Caucasian’ and ‘Plains’ Bluestem Grasses as Affected by Clipping Interval1
Authors: Taliaferro C. M. , Horn F. P. , Ahring R. M. , Weeks D. L. 
Published: July 2010

AbstractUse of introduced bluestems (Bothriochloaspp.) as pasture grasses in the southern Great Plains is increasing. Information is limited on the effects of management variables on the yield and quality of their forage. This field experiment was conducted on Pachic Paleustoll soil for 3 years (1974 to 1976), in order to assess the relative yield and quality of forage and stand persistence of the ‘Plains’ [B. ischaemum(L.) Keng. var. ischaemum] and ‘Caucasian’ [B. caucasica(Trin.) C. E. Hubb.] cvs. as affected by different clipping intervals (3, 5, 7,9, or 11 weeks between clippings). Cultivars were randomly assigned to whole plots and clipping intervals to subplots in a split‐plot, randomized complete block experiment. Significant differences due to cultivars were measured only in 1974 for dry matter (DM) and in vitro digestible dry matter (IVDDM) yields and in 1975 and 1976 for percent in vitro dry matter disappearance (IVDMD). The difference in 3‐year IVDMD of the cultivars (Plains = 60.1, Caucasian = 57.3) was also significant. Intervals between clippings affected DM and FVDDM yields and IVDMD each year. The DM and IVDDM yields increased as harvest interval increased from 3 to 7 weeks, where they generally peaked, but there was significant lack of fit to quadratic responses for DM and IVDDM yield in 2 of the 3 years. The IVDMD of the cultivars decreased linearly in 1974 and 1975 as clipping interval decreased. In 1976, the IVDMD response of the cultivars was different and deviated significantly from quadratic. The data suggest that the basic responses of Plains and Caucasian bluestem to clipping interval are characteristic of the responses of most forages. The length of the interval between harvests at which digestible dry matter will be maximized in a given year will vary with environmental conditions but probably would seldom exceed 7 weeks. Clipping interval had no effect on subsequent spring DM yield of the Caucasian cultivar but there was some reduction in first harvest DM yield of Plains due to frequent clipping during the previous season.
Effective Rates of Fertilization for Correcting Manganese Deficiency in Soybeans1
Authors: Mascagni H. J. , Cox F. R. 
Published: July 2010

AbstractManganese deficiencies occur in soybeans (Glycine max L.) grown on slightly acid to alkaline soils in the Atlantic Coastal Plain and efficient, effective corrective measures are needed. The optimum rate of Mn needed is not well defined for any method of application. Field studies were conducted to establish the most efficient rate for broadcast and band methods of soil application and for foliar application. The best time to begin foliar spraying and the number of sprayings required were also determined. Manganese sulfate was the Mn source. Manganese rate treatments for the broadcast, band, and foliar applications ranged from 0 to 90, 0 to 13, and 0 to 2.2 kg Mn ha−1, respectively. Optimum yields were obtained with broadcast Mn applied at 14 kg Mn ha−1 and band applications of 3 kg Mn ha−1. For foliar applications, rates as low as 0.1 kg ha−1 were sufficient, but spraying should begin as soon as symptoms appear and should be repeated at least once under severely deficient conditions.
Nitrate Monitoring for Cotton Lint Production on a Typic Paleudult1
Authors: Lutrick M. C. , Peacock H. A. , Cornell J. A. 
Published: July 2010

AbstractDiagnostic criteria for monitoring the N status of both soil and cotton plant are needed to aid in adjusting N fertilization to compensate for seasonal variations. A 3‐yr study was initiated in 1981 to determine the feasibility of using soil and petiole NO−3–N testing as an aid in cotton (Gossypium hirsutum L.) lint production along the Gulf Coast. A factorial experiment with four rates of N, three rates of K, and four replications was established on an Orangeburg fine sandy loam (fine‐loamy, siliceous, thermic Typic Paleudult). Soil samples were taken each year just prior to the addition of N and K fertilizer treatments. Response to K fertilization was not significant. Cotton petiole samples were taken on selected plots for 9 weeks beginning 1 week prior to first bloom. The response to N resulted in a 3‐yr average maximum yield of 1294 kg ha−1 of lint cotton from 114 kg ha−1 of applied N. Petiole analyses for NO−3–N indicated that additional N should be applied to all treatments after the second week of petiole sampling, even though lint yields were above average in this study (average yield for this soil is 1008 kg ha−1). This suggests that the sufficient‐N zone established for petiole analyses of NO−3–N in Arkansas and accepted in Georgia is higher than is desirable for thermic Typic Paleudults. Repeated applications of N to the soil over the 3 yr of the experiment did increase the amount of NO−3–N extracted from the soil indicating that some of the applied N was not used by the cotton plant. A revised NO−3–N sufficient‐N zone, developed by Georgia researchers and first used in 1985, conforms with the data presented in this paper and could be used satisfactorily to determine N recommendations from petiole analyses for cotton lint production on thermic Typic Paleudults of the Gulf Coast of Florida.
Time Course of Nitrogen Fixation in Field‐Grown Soybean Using Nitrogen‐15 Methodology1
Authors: Zapata F. , Danso S. K. A. , Hardarson G. , Fried M. 
Published: July 2010

AbstractThe use of 15N techniques allows for the quantitative evaluation of N2 fixation and distribution and their impact on the N balance in various soil‐plant systems. The A‐value approach was used in this investigation to assess N2 fixed at various growth stages in fieldgrown soybean [Glycine max (L.) Merrill] cv. Chippewa in a Typic Eutrocrepts soil. At physiological maturity (R7), the amount of N derived from fixation (Ndfa) was 102 kg/ha, equivalent to 47% of total N assimilated, while the contributions from soil (Ndfs) and 15N‐labelled fertilizer (Ndff) accounted for 50 and 3%, respectively. Up to growth stage V6, which occupied half of the total duration of growth, Ndfa was less than 5% of N2 fixed by physiological maturity. A rapid increase in Ndfa occurred from R1 onwards, and during the reproductive stages (R1‐R4), which spanned less than one‐third of the total duration of growth, this represented about 45% of total Ndfa. An almost equal portion of N (approximately 43%) was fixed from pod‐filling (R5) to physiological maturity (R7), a period slightly more than one‐fifth of the total duration of growth. Therefore, substantial N2 fixation occurred during periods of active sink development and contributed more than 65% of the plant's N accrued during pod fill (R3‐R7). Nitrogen assimilated between R3 and R7 (when N2 fixation was high) seemed to be the predominant source of N for pod development. Thus there was a greater contribution from fixed N (55%) than soil N (43%) in pods and seeds at the end of R7. After grain removal, it was estimated that the growth of cv. Chippewa in this soil led to a net soil depletion of 54 kg N/ha.
Evaluation of Oxamide as a Slow‐Release Nitrogen Source on Kentucky Bluegrass1
Authors: Mosdell D. K. , Daniel W. H. , Freeborg R. P. 
Published: July 2010

AbstractSlow‐release N fertilizers are used in turfgrass fertilization programs to reduce foliar burn and N losses, and to extend the response period between applications. In this study, oxamide (31% N), an amide of oxalic acid, and a 7:3 N ratio of oxamide and urea were evaluated as slow release N sources on Kentucky bluegrass (Poa pratensis L.) at West Lafayette, IN, on a Toronto silt loam soil (fine‐silty, mixed mesic, Udollic Ochraqualfs). Two particle sizes of oxamide, C (1–2.8 mm) and F (<0.85 mm), were applied as a granular and liquid suspension treatment, respectively. Additional treatments consisted of applying isobutylidene diurea (IBDU), sulfur‐coated urea (SCU), and urea. Two and four applications were made, with a total annual application rate of 196 kg N ha−1 yr−1. Recovery of N in the tissue from applications of oxamide C was 51% compared to 41, 39, and 38% for IBDU, oxamide F, and SCU, respectively, averaged over 3 yr. Initial change in visual turf quality and clipping yields in response to oxamide C was slow, similar to that of IBDU; however, residual N release was equal to that of IBDU and greater than that of SCU. Adding urea to oxamide C increased initial yields and turf quality but reduced the duration of turf response as compared to applications of oxamide C alone. At two applications of 98 kg N ha−1, oxamide proved to be a good, slow‐release source of N. At four applications per year, initial clipping yields resulting from spring oxamide F applications were lower than those from urea, but turf quality in response to residual N tended to be greater than that of urea. Late fall applications of oxamide F reduced soil NO−3 concentrations shortly after application and in early spring as compared to fall applications of urea. Oxamide F at four applications generally produced a more desirable turf response than did similar applications of urea.
Aerial Parts of Hard Red Spring Wheat. III. Nitrogen and Phosphorus Concentration and Content in Kernels, Anthesis to Ripe Stage1
Authors: Bauer Armand , Frank A. B. , Black A. L. 
Published: July 2010

AbstractInformation is lacking on N and P concentration and content in kernels of hard red spring wheat (Triticum aestivum L.) over the course of grain filling. Such information would be of benefit in making nutrient management decisions and provide algorithms for plant development/yield modelers. Concentration and content of N and P were measured twice weekly in composited kernels of all spikes from a 1‐m length of row, field‐grown on Williams loam (fine‐loamy, mixed Typic Argiborolls), during 3 crop years with fertilizer N rates, cultivars, and water management variables. Concentrations and contents were regressed with both days (DAYS) and growing degree‐days (GDD) accumulated from anthesis. With all treatments combined, the R2 relating kernel N and P concentration to DAYS was 0.45 and 0.49, respectively, and to GDD, 0.44 and 0.41, respectively. Peak N and P concentration, about 46.2 and 8.3 g kg−1, respectively, occurred within 1 to 2 DAYS after anthesis. Concentration at maximum kernel dry matter was 33.1 and 5.0 g kg−1 for N and P, respectively. The R2 relating kernel N and P content to DAYS was 0.95 and 0.92, respectively, and to GDD, 0.95 and 0.92, respectively. The N and P content increased about 30 µg N and 4.7 µg P kernel−1 DAY−1 during the constant‐rate phase of grain filling. Both N and P uptake closely paralleled kernel dry matter assimilation.
Evapotranspiration of Cool‐Season Turfgrasses in the Humid Northeast1
Authors: Aronson L. J. , Gold A. J. , Hull R. J. , Cisar J. L. 
Published: July 2010

AbstractAs competition for water increases in the northeastern United States, turfgrass culture must be directed toward practices that will lower water requirements. This study was conducted to quantify and compare the evapotranspiration (ET) rate of well‐watered grasses in the humid Northeast. Predictive methods for irrigation scheduling of turf were also evaluated. Weighing lysimeters, 0.25 m in diameter and 0.28 m deep, were placed into field plots of well‐watered mature turf growing on an Enfield silt loam (coarse‐silty over sandy‐skeletal, mixed, mesic Typic Dystrocrept), and ET was determined by weighing the lysimeters at 24‐h intervals throughout the summers of 1984 and 1985. The grasses studied were: Poa pratensis L, ‘Baron’ and ‘Enmundi’; Lolium perenne L., ‘Yorktown II’; Festuca rubra var. cummutata Gaud., ‘Jamestown’ and Festuca ovina var. duriuscula (L.) Koch, ‘Tournament’. Consistent annual differences were not observed in the variable summer weather that characterizes southern New England. Daily meteorological data were used to calculate reference ET by the modified Penman equation and from pan evaporation. A crop coefficient (Kc) was calculated for each grass as the ratio of ET measured to ET predicted. Seasonal Kc values based on the Penman equation ranged from 0.88 for Tournament in 1984, to 1.09 for Enmundi in 1985 (CV, 0.15–0.30). Seasonal Kc based on pan evaporation data was more variable, ranging from 0.86 to 1.31 (CV, 0.34–0.44). The Penman equation predicted ET more consistently, and could provide a reliable and useful tool for irrigation scheduling of turfgrass in southern New England.
Planting Date in Relation to Yield and Yield Components of Wheat in the Middle Atlantic Region
Authors: Rocheford T. R. , Sammons D. J. , Baenziger P. S. 
Published: July 2010

AbstractA 2‐yr study was conducted to assess the effects of early and late planting on six soft red winter wheat (Triticum aestivum L.) cultivars. The purpose was to determine if increased flexibility in planting date is possible for modern wheat cultivars grown in the Middle Atlantic states. Wheat was planted 2 wk prior to, on, and 2 wk after the recommended fly‐free planting date at Clarksville (Piedmont Province) and Queenstown (Coastal Plain Province), MD. Grain yield and yield components (spikes per square meter, kernels per spike, and kernel weight) were measured. Planting date × location, and planting date × location × year interactions for grain yield occurred. At Clarksville, there were no significant differences in average grain yield among planting dates the first year, whereas a significant and progressive decline in average grain yield occurred with each delay in planting the second year. At Queenstown, early planted wheat produced a higher grain yield than wheat planted on the recommended and late planting dates the first year, whereas early planted wheat yielded less than wheat seeded on subsequent planting dates the second year. In general, changes in spikes per square meter were the major contributors to the yield differences observed among planting dates at both locations. Individual cultivars were variable in yield performance on the different planting dates. Although there was considerable environmental variation in crop performance, increased flexibility in planting date for winter wheat production in the Middle Atlantic states may be possible for certain wheat cultivars. Cultivar and environmental factors will play a large role in determining the success of such a change in current management practices.
Statistical Error Rates and Their Implications in Sugarcane Clone Trials
Authors: Glaz B. , Dean J. L. 
Published: July 2010

AbstractThere is an estimated difference of 18 h ha−1 in the amount of time required to cut the two most widely grown sugarcane (Saccharum spp.) clones in Florida, but this characteristic is neither analyzed nor considered in deciding if a clone should be released. The major objective of this study was to determine optimum type I and type II error rates (α and β levels) at which to perform significance tests for this characteristic at our current sample size and error variance (σ2). The minimum detectable difference (δ) was set at 18 h ha−1, the relative seriousness of type I versus type II errors was subjectively assessed, and the advantages and disadvantages of using various levels of α and β were then discussed. Analyses were performed for a group of 12 clones cultivated at five locations, from plant crop through second‐ratoon crop. It was determined most appropriate to use α = 0.10 so that β would approximate 0.04. The results indicate that at levels of α≤0.05, type II error rates are unacceptably high. For research projects in which type II errors have some negative consequences, researchers should estimate β at various a levels and set α at a level that appropriately balances type I and type II error rates.
Subterranean Clover Cover Crop Used to Increase Rice Yield
Authors: Dabney S. M. , Breitenbeck G. A. , Griffin J. L. , Hoff B. J. 
Published: July 2010

AbstractManagement systems for flooded rice (Oryza sativa L.) production that include a winter legume cover crop and no‐till planting are of interest to farmers seeking lower‐cost production methods. Field experiments were performed at Crowley and Baton Rouge, LA. The purpose was to determine the effects of N fertilization (0, 56, 112, and 168 kg urea‐N ha−1) and tillage (rototilling or no‐tillage) on the yield and yield components of rice planted in fallow plots or in plots containing subterranean clover (Trifolium subterraneum L.) that had produced mature seed. Rice was dry‐seeded 1 wk after clover was desiccated with an herbicide or tilled into the soil. A permanent flood was established 30 d after planting. The presence of a clover cover crop increased rice yields about 10% in tilled and no‐till plots receiving various rates of N fertilizer. Flag‐leaf N concentrations and the amounts of total N assimilated into above‐ground biomass at harvest were greater in rice after clover than in rice after fallow, but the presence of a winter clover cover did not reduce the amount of N fertilizer required to produce maximum yield. The maximum yields of rice obtained by no‐till management were similar to or greater than those obtained by tillage. After rice harvest, stands of reseeded subterranean clover were better in no‐till plots than in plots where clover residues had been incorporated into the soil prior to rice planting.