bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of LEACHM: I. Simulation of Drainage, Bromide Leaching, and Corn Bromide Uptake
Authors: Jemison John M. , Jabro Jalal D. , Fox Richard H. 
Published: July 2010

AbstractUse of mathematical models to predict solute transport in soils, for research purposes, is increasing, but simpler management‐oriented models are needed that require less field‐specific data. Evaluation is needed to know which type of model is appropriate. The input‐intensive research and simpler management options of the pesticide and tracer version of LEACHM (LEACHMP) were evaluated to predict drainage in zerotension pan lysimeters, bromide (Br−) leaching, and corn (Zea mays L.) Br− uptake from a 3‐yr leaching experiment. Eighteen pan lysimeters (0465 m2) were installed 1.2 m below the soil surface to collect gravitational water samples. In May 1988, a one‐time application of KBr was broadcast to all plots at 100 kg Br− ha−1. Corn Br− uptake was evaluated by taking whole‐plant samples at 2‐wk intervals in 1988 and 1989. The research model adequately predicted drainage. Significant differences between predicted and observed drainage were not found, and the correlations were significant (0.73 to 0.83). The management model, however, significantly underestimated cumulative drainage. The research model overestimated Br− leaching, because the convectiondispersion equation used in LEACHMP cannot model dual‐pore water flow and solute diffusion found in this soil. The model generally underpredicted corn Br− uptake, which probably contributed to the overpredicted Br− leaching. The research version of LEACHMP adequately modeled drainage, but a more sophisticated approach to solute transport and corn Br− uptake is needed to adequately model Br− movement in this soil‐plant‐water system. Management model results were generally less accurate than the research model.
An Approach for Estimating a Decay Series for Organic Nitrogen in Animal Manure
Authors: Klausner Stuart D. , Kanneganti V. Rao , Bouldin David R. 
Published: July 2010

AbstractAnimal manures are an important source of N for crop production. Efficient use of manure is necessary to increase N recycling, eliminate excessive purchase of fertilizer N, and reduce N loss to the environment. An estimate of the annual rate of organic N mineralization in manure is a necessary prerequisite to efficient manure N management. A mineralization or decay series for the organic N in dairy manure was estimated for corn (Zea mays L.) production from several field experiments over a 5‐ to 8‐yr period. Four rates of sidedressed fertilizer N (0, 56, 112, and 224 kg N ha−1) were superimposed over several springapplied manure treatments ranging from 0 to 168 Mg ha−1 yr−1. Ammonia volatilization from manure was encouraged, to allow for an assessment of the fertilizer N equivalence of the more stable organic N fraction. Based on silage dry matter yield and N uptake, a decay series of 0.16, 0.10, 0.03, 0.03 and 0.02, and 0.21, 0.09, 0.03, 0.03 and 0.02, respectively, described the fertilizer N equivalence of organic N. The first number in the decay series estimates the fraction of organic N that is available for crop use during the year of application, and the second to fifth numbers are estimates of available N from residual N in Years 2 through 5. An independent set of field data was used to evaluate the accuracy of the decay series. The predicted decay series, based on dry matter yield (R2 = 0.16) was more variable than the corresponding decay series based on N uptake (R2 = 0.72). The non‐N effects of manure were insignificant, and therefore yield and N uptake were directly related to the N contribution.
Fate of Legume and Fertilizer Nitrogen‐15 in a Long‐Term Cropping Systems Experiment
Authors: Harris Glendon H. , Hesterman Oran B. , Paul Eldor A. , Peters Steven E. , Janke Rhonda R. 
Published: July 2010

AbstractRelying more on biological N2 fixation has been suggested as a way to meet one of the major challenges of agricultural sustainability. A 15N study was conducted to compare the fate of applied legume and fertilizer N in a long‐term cropping systems experiment. Nitrogen‐15–1abeled red clover (Trifolium pratense L.) and (NH4)2SO4 were applied to microplots within the low‐input and conventional cropping systems of the Farming Systems Trial at the Rodale Institute Research Center in Pennsylvania. The 15N was applied to soil and traced into corn (Zea mays L.) in 1987 and 1988. Residual 15N was also traced into second‐year spring barley (Hordeum vulgare L.). Legume and fertilizer 15N remaining in soil was measured and loss of N was calculated by difference. More fertilizer than legume N was recovered by crops (40 vs. 17% of input), more legume than fertilizer N was retained in soil (47 vs. 17% of input), and similar amounts of N from both sources were lost from the cropping systems (39% of input) over the 2‐yr period. More fertilizer than legume N was lost during the year of application (38 vs. 18% of input), but more legume than fertilizer N was lost the year after application (17 vs. 4% of input). Residual fertilizer and legume 15N was distributed similarly among soil fractions. Soil microbial biomass was larger in the legume‐based system. A larger, but not necessarily more active, soil microbial biomass was probably responsible for the greater soil N supplying capacity in the legume‐based compared with fertilizer‐based system.
Root Distribution of Corn: The Effect of Nitrogen Fertilization
Authors: Durieux Robert P. , Kamprath Eugene J. , Jackson William A. , Moll Robert H. 
Published: July 2010

AbstractRoot growth and development can affect N uptake. In turn, N additions may affect corn (Zea mays L.) root growth. Prolific (multiple ear) hybrids may need a more active root system to satisfy ear demand. To determine the extent of the effect of N fertilization on root growth in the field, three corn hybrids (Pioneer 3320, and prolific hybrids I202×Mol7 and I117×B73) were grown under fertilizer application rates of 56, 140, and 224 kg N ha−1 to determine (i) whether application of N fertilizer stimulated root growth of corn in the zone of application in the field 20 d before silking, at silking, and at physiological maturity and (ii) whether prolific hybrids have enhanced root development before silking compared with nonprolific hybrids. All three hybrids were grown at a uniformly low plant‐population density. Root length density to a depth of 60 cm, averaged over hybrids, was 1302, 2238, and 1184 m plant−1 in 1987, and 2195, 2833, and 3317 m plant−1 in 1988 for the three sampling dates. There were few genotypic differences in root length density. Root weight averaged over hybrids was 20.4, 40.5, and 21.5 g plant−1 in 1987, and 44.6, 61.7, and 58.9 g plant−1 in 1988 for the three sampling times, respectively. Root weight at harvest declined as N application increased, but increased in response to N at two earlier sampling times. The second year of the study, when rainfall was more plentiful than in the first year, root growth continued after silking for all hybrids. This coincided with higher yields. The data suggest that N stimulated root length in the area of application, without affecting total root length.
Optimizing Yield and Grain Protein in Soft White Winter Wheat with Split Nitrogen Applications
Authors: Sowers Karen E. , Miller Baird C. , Pan William L. 
Published: July 2010

AbstractGrain protein of soft white winter wheat (Triticum aestivum L.) produced in eastern Washington has increased above market‐desired levels over the past decade, when subnormal precipitation and overfertilization contributed to excessive residual soil N levels. A field study was conducted over four site‐years to (i) examine N effects on the yield‐protein relationship of soft white winter wheat under high soil N conditions, (ii) determine if split N applications can maintain yield and reduce grain protein, and (iii) evaluate midseason grain analysis as a predictor of final grain protein. Nitrogen rates ranged from 0 to 140 kg N ha−1; timing treatments were fall preplant N and spring topdressed or point‐injected N. High yields (>5900 kg ha−1) were produced without fertilizer N, and yield responses to N ranged from 0 to 22%. Fall N < 56 kg N ha−1 increased yield in only one site‐year; yields were reduced due to excess N fertilization in another site‐year in conjunction with shallow N depletion and poor water extraction from deeper soil layers. In two of four site‐years, yield increased with a 50% fall‐50% spring point‐injected N compared with 100% fall application at 84 kg total N ha−1. Protein >100 g kg−1 was produced in site‐years where most soil N was depleted below the 90‐cm depth; shallow N depletion was associated with lower protein. Grain N concentration at maturity was highly correlated with grain N concentration at the late milk and soft dough stages. Preharvest predictions of final grain protein may be useful in segregating grain at harvest for marketing purposes. Under high residual soil N levels, reduced N rates and split N applications between fall and spring can maintain high yields and reduce grain protein.
Feeding Activity, Growth, and Survival of Soybean Looper on Low‐Nitrogen Nonnodulating Soybean
Authors: Wier Alan T. , Boethel David J. 
Published: July 2010

AbstractFeeding and larval development of several lepidopteran species are influenced by reduced foliage N of host plants. Nonnodulating soybean [Glycine max (L.) Merr.] isolines have exhibited foliar symptoms typical of N deficiency in field plots in absence of supplemental N. Under these chlorotic conditions, reducedefoliation and larval development of soybean looper [Lepidoptera:Noctuidae, Pseudoplusia includens (Walker)] have been observed. This study was conducted to evaluate the influence of foliage N level of nodulating and nonnodulating soybean isolines on feeding and development of the soybean looper. Two feeding studies involving the soybean looper and foliage of nodulating and nonnodulating isolines of #x2018;Clark’ soybean were conducted using foliage collected from plants in full bloom (R2) and in the beginning seed stage (R5). The foliage N level of the nonnodulating isoline was not significantly lower than that of the nodulating isoline when collected at R2 and, consequently, only slight effects on feeding and development were attributable to consumption of nonnodulating isoline foliage. However, chlorosis and a 43% reduction in the foliage N level of the nonnodulating isoline occurred by R5, resulting in limited compensatory feeding, extended larval development, and reduced survival when soybean loopers consumed this isoline. Foliage N concentrations of ≈40 mg g−1 leaf dry weight were sufficient for soybean looper development from the neonate to the adult stage, while concentrations of 23 mg g−1 leaf dry weight were inhibitory.
Sowing Date Effects on Grain Yield Components for Different Maize Genotypes
Authors: Otegui María E. , Nicolini María G. , Ruiz Ricardo A. , Dodds Pablo A. 
Published: July 2010

AbstractShoot dry weight of maize (Zea mays L.) depends on the amount of photosynthetically active radiation intercepted by the crop (IPAR). The present work was conducted to analyze the variation in shoot dry weight production and its partitioning to reproductive sinks when seasonal changes of temperature and solar radiation occur during the growing cycle of the crop. Four commercial hybrids were grown at 8 plants m−2 on four sowing dates (20 Aug., 20 Sept., 20 Oct., and 20 Nov.) at Rojas (34° 08' S, 60° 59' W), Argentina, on a silty clay loam soil (Typic Argiudoll) during 1990‐1991 and 1991‐1992, with no water or nutrient restrictions. Shoot dry weight at physiological maturity was associated with the amount of IPAR, with radiation use efficiency before silking (4.14 g MJ−1) higher than after silking (2.45 g MJ−1). Grain yield was correlated with shoot dry weight at physiological maturity, resulting in a stable (0.46 ± 0.02) harvest index. Shoot dry weight at silking showed a significant relationship with final grain number (r2 = 0.52, n = 32) as well as with grain yield (r2 = 0.55, n = 32). Ear dry weight at silking was associated with grain yield particularly for prolific hybrids (r2 = 0.64, n = 16). Provided postsilking conditions do not limit assimilate supply to the grains, shoot dry weight at silking could be considered a good grain yield predictor. In temperate regions, maize potential productivity seems to be more limited by the amount of solar radiation available around silking (determinant of grain set) than during grain filling (determinant of grain weight). Early and intermediate sowings tend to best utilize solar radiation for grain production.
Regression and AMMI Analyses of Genotype × Environment Interactions: An Empirical Comparison
Authors: Yau Sui K. 
Published: July 2010

AbstractJoint regression analysis (JRA) is a popular method for analyzing genotype × environment (G × E) interactions, but multivariate techniques such as AMMI (additive main effects and multiplicative interaction) analysis have been recently advocated. The objective of this study was to investigate and compare empirically the effectiveness of the two techniques under differing environmental diversity and numbers of environments, and when log‐transformed data were used for JRA. I analyzed grain yield data from three seasons of a regional bread wheat (Triticum aestivum L.) yield trial, grown at 30 to 40 sites. Sites were split into irrigated‐high rainfall and rainfed‐low rainfall groups. Three equal‐size samples differing in environmental diversity and three similar diversity samples differing in numbers of sites were also formed. Both raw and log10‐transformed data were used for JRA. The fitting mode of the MATMODEL program (version 2.0) was used on raw data for AMMI analysis. Percentages of interaction sum of squares (SS) accounted for by heterogeneity of regression in JRA were generally low (mean = 11%) and unaffected by diversity of the samples, but inversely related to number of sites in the similar‐diversity samples. In contrast, percentages of interaction SS accounted for by first principal components in AMMI analyses were generally high (mean = 37%) and unaffected by diversity or number of sites in the samples. These percentages were always higher for AMMI than for JRA, regardless of whether log‐transformed data were used for JRA. The use of AMMI is recommended for detailed studies of G × E effects, especially for large regional or international trials.
Establishing a Rejection Procedure for Crop Performance Data
Authors: Bowman Daryl T. , Rawlings John O. 
Published: July 2010

AbstractCrop performance trials are conducted to provide unbiased relative performance data for breeders, growers, and extension personnel. This report presents a method for establishing a criterion level of precision for rejection of questionable data. For a given crop, historical data (a minimum of 30 data points) are used to calculate average error variance and to determine any relationship between productivity level and error variance by regressing log(variance) on log(mean) for the variable of primary interest, usually yield. A nonsignificant relationship dictates using the pooled error variance over all trials as the reference or expected variance; a significant relationship dictates using the fitted variance predicted from the regression at the observed mean yield of each trial. An upper bound on error variance (a multiple k of the expected error variance) is calculated. Any trial with an observed error variance above the upper bound would be discarded as having unusually low precision. Historical data from five crop species tested in North Carolina were examined as working examples. Of eight data sets, four showed no relationship between variance and productivity level on a log‐log scale. Compared with corn and soybean, more small‐grain (barley, oat, and wheat) trials were above the criterion level when k = 2. Thus, k‐values may need to be adjusted among crop species. Most trials with unacceptably low precision showed a record of some sort of problem, although it could not be confirmed that the noted problem caused the high variability. Researchers using the proposed procedure are cautioned to examine their data closely to ensure an appropriate k‐value and to note test sites of low precision or methods causing low precision.
Surface Runoff Assessment from Creeping Bentgrass and Perennial Ryegrass Turf
Authors: Linde Douglas T. , Watschke Thomas L. , Jarrett Albert R. , Borger Jeffrey A. 
Published: July 2010

AbstractThe potential for offsite movement of nutrients and pesticides in surface runoff from golf courses has generated a need to better understand the movement of water from intensely maintained turfgrass. This study assessed the influence that creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw.; syn. Agrostis palustris Huds.] and perennial ryegrass (Lolium perenne L.) had on the surface movement of water when maintained similarly to golf fairways. On eight dates, 123.5‐m2 sloped plots of bentgrass and ryegrass were irrigated at 152 mm h−1 to force runoff for the generation of hydragraphs. As the grasses matured, runoff from ryegrass occurred earlier and at greater volumes than from bentgrass. Four additional experiments were conducted to provide some explanation of these runoff differences. In one experiment, average infiltration rates for the bentgrass (64 mm h−1) and ryegrass (35 mm h−1) plots were not significantly different, because of high sampling variation. In an experiment that used 0.25‐m2 sloped trays of turf, bentgrass retarded the flow of surface runoff through its vegetation significantly longer than ryegrass. It was also found that bentgrass (1410 tillers dm−2) intercepted 113% more water than ryegrass (260 tillers dm−2), and that bentgrass thatch slowed runoff initiation because of its high water‐holding capacity and increased hydraulic resistance. The high‐density, thatch‐forming bentgrass provided a more tortuous pathway for water movement, which increased resistance and in turn increased residence time and allowed for greater infiltration. For golf courses that have potential runoff concerns, the selection of creeping bentgrass rather than perennial ryegrass could reduce surface runoff from golf fairways.
Soybean Seed Number and Crop Growth Rate during Flowering
Authors: Jiang Hongfei , Egli Dennis B. 
Published: July 2010

AbstractSeeds per unit area is an important yield component in soybean [Glycine max (L.) Merrill]; however, the mechanisms regulating seed number are not well understood. Field and greenhouse experiments were conducted to investigate the relationship between photosynthesis during flowering and podset and seeds per square meter. Shade cloth (30 and 63% reduction in insolation) was used to reduce photosynthesis from emergence to Growth Stage R1 in the field ['Pennyrile' (indeterminate) and 'Ripley' (determinate)] or for varying periods during flowering and podset in the greenhouse ('McCall') and field (Pennyrile). Shade during vegetative growth reduced mass per square meter (21‐52%) at Growth Stage R1, but had no effect on crop growth rate (CGR) during flowering and podset (R1 to R5) or seeds per square meter if light interception after R1 was not reduced. Shade during flowering and podset reduced seeds per square meter in relation to the length of the shade treatment. In the field, shade from R1 to R4 and R4 to R6 had similar effects on seeds per square meter; these were less (31%) than the unshaded control for both treatments. These results suggest that maximum photosynthesis throughout flowering and podset may be required to maximize seeds per square meter. There were linear relationships between average CGR during R1 to R5 and seeds per square meter across experiments and treatments in both field and greenhouse. These relationships support previous results suggesting that seeds per square meter is determined primarily by canopy photosynthesis during flowering and podset.
Corn Responses to Chloride in Maximum Yield Research
Authors: Heckman Joseph R. 
Published: July 2010

AbstractChloride nutrition of corn (Zea mays L.) was investigated to determine if Cl limits production in high‐yield environments. Experiments were conducted to evaluate the effects of Cl fertilization on a Freehold sandy loam (fine‐loamy, mixed, mesic Typic Hapludults) near Adelphia, NJ, using irrigation and intensive crop production practices. Corn was grown at 107 600 plant ha−1 with equidistant spacing. All plots received 454 kg K ha−1 using KOH, K2SO4, or KCl to establish five treatments: 0, 50, 100, 200, and 400 kg Cl ha−1. Positive responses of corn to added Cl were observed each year. In 1990, the Cl treatments averaged 1.1 Mg ha−1 more grain than the check yield of 11.3 Mg ha−1 (P = 0.08). In 1991, the check yield was 19.0 Mg ha−1 and the response to Cl was linear up to the 400 kg ha−1 rate, which yielded 20.5 Mg ha−1. In 1992, the Cl treatments averaged 0.5 Mg ha−1 more grain than the check yield of 14.5 Mg ha−1 (P = 0.07). Grain yields were positively correlated with increases in ear‐leaf Cl concentration. Increases in grain yield were associated with increased ear size. Chloride did not increase stover yield. A linear decrease in incidence of stalk rot with Cl rate was observed in 1992. Results suggest that, when produced in high‐yield environments, corn may respond to enhanced levels of Cl nutrition.
Paper Mill Boiler Ash and Lime By‐Products as Soil Liming Materials
Authors: Muse John K. , Mitchell Charles C. 
Published: July 2010

AbstractThe pulp and paper industry in the southeastern USA produces ≈ 6500 t of boiler ash and lime by‐products (waste lime, grit, and dregs) daily. A survey of 88 pulp and paper mills indicated that most of these by‐products are placed in landfills, with only 10% being land‐applied. Seventeen boiler ash samples and 14 lime by‐products from 12 Alabama pulp and paper mills were analyzed and evaluated for their potential as soil liming materials. Most boiler ash resulted from the burning of wood or wood in combination with other materials and averaged 37% calcium carbonate equivalent (CCE), while 14 lime by‐products averaged 99% CCE. In an 84‐d incubation study, boiler ash and lime by‐products applied to an acid (pH = 5.2) Marvyn loamy sand (fine‐loamy, siliceous, thermic, Typic Kanhapludults) at equivalent rates based on CCE resulted in mean pH values significantly higher than values achieved with agricultural lime. All materials increased Mehlich‐1 extractable P, K, and Mg. In a field study conducted on an acid (pH = 5.1) Vaiden clay (very‐fine, montmorillonitic, thermic Vertic Hapludalfs), dallisgrass‐fescue (Paspalum dilatatum Poir.‐Festuca arundinacea Schreb.) herbage yield increased 62% the second year and 49% the third year after surface application of boiler ash, lime by‐products, and agricultural lime.