bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen Mineralization Potential and Nitrogen Transformations of Sludge‐Amended Soil
Authors: Lindemann W. C. , Cardenas M. 
Published: July 2010

AbstractAn experiment was conducted to determine values for the mineralization potential (No), rate constant (k), and rate of mineralization for soils freshly amended with sewage sludge, and to determine the influence of soil type and sludge rate on these values. A secondary objective was to determine if the sum of two exponential functions could better model N mineralization than a single exponential functions, as is normally used. A clayey soil (Glendale, a Typic Torrifluvent) and a sandy soil (Latene, a Typic Calciorthid) were amended with three rates (0, 15, and 30 g kg−1) of gamma irradiated, dried, anaerobically digested sewage sludge. The Glendale soil was mixed with sand (1:1 by weight) to increase aeration. Triplicate 80‐g samples of each soil mixture were incubated aerobically for 32 weeks at 0.01 MPa moisture tension and 35°C. Before incubation and periodically during incubation, the soils were leached with 0.01M CaCl2 and the leachate analyzed for NH+4, NO‐2, and NO‐3. No and k were estimated by a nonlinear least squares iterative statistical method. Cumulative (NO‐3 + NO‐2)‐N at the end of 32 weeks was dependent on sludge rate, but not on soil type or the soil type‐sludge rate interaction. Cumulative (NO‐3 + NO‐2)‐N for the 0, 15, and 30 g kg−1 treatments were 60.9, 137.4, and 182.6 mg (NO‐3 + NO‐2)‐N kg−1, respectively. Mineralization rates decreased rapidly the first two weeks, followed by a slower decrease with time. Rates were higher in sludge‐amended soil than in unamended soil and averaged 0.6, 1.8, and 2.2 mg (NO‐3 + NO‐2)‐N kg−1 week−1 for the 0, 15, and 30 g kg−1 treatments, respectively, after 32 weeks. Several methods of estimating No and k were attempted. The best estimates for sludge‐amended soil were obtained by modelling N mineralization as the sum of two exponentials. Total N mineralization (organic N loss, x̄ (mean) = 63%) was more than twice that of net N mineralization (NO‐3 + NO‐2‐N accumulated, x̄ = 27%). Total and net mineralization were greater in the Glendale soil (x̄ = 68% and 30%, respectively) than in the Latene soil (x̄ = 58% and 24%, respectively). Total mineralization increased with sludge addition, but net mineralization decreased with sludge addition. Denitrification losses probably accounted for the discrepancies between total and net mineralization. Denitrification increased with sludge addition and was greater in the Glendale than the Latene soil.
Relationships among Anaerobically Mineralized Nitrogen, Chemical Indexes, and Nitrogen Availability to Corn
Authors: Fox Richard H. , Piekielek William P. 
Published: July 2010

AbstractAn accurate method for predicting the N supplying capability of a soil must be available in order to increase N fertilizer efficiency in humid areas with a mixed agriculture that includes N inputs from livestock manure and forage legumes. Previous work had shown that a number of chemical N availability tests were not well correlated (r < 0.4) with the soil N available to field grown corn (Zea mays L.) in 67 experiments throughout Pennsylvania over a 6‐y period. Soils from these same sites were anaerobically incubated for 7 d to determine if the N mineralized during this period would be better correlated with field‐measured N availability than the chemical indexes. The anaerobically mineralized N was no better correlated with field N availability than were the chemical indexes. Anaerobically mineralized N was most closely correlated with total soil N content (r = 0.79) and boiling 0.01M CaCl2 extractable N (r = 0.74). By restricting the experimental sites to well‐drained soils where a legume (primarily alfalfa) had not been growing in either of the 2 years preceding the experiment, the correlation coefficients between two of the indexes, the UV absorbance of a boiling 0.01M CaCl2 extract and NO3 content of the surface 40 cm of soil at planting, and the field estimate of N availability were increased to 0.65 and 0.59, respectively. A stepwise multiple regression analysis using field N availability selected these two estimates with a resulting coefficient of determination (R2) of 0.50. These results are encouraging but are not high enough to use in a routine soil testing laboratory. Restricting the soils as described did not improve the correlation between anaerobically mineralized N and field‐measured N availability. Nitrogen fertilizer recommendations for corn based on current Pennsylvania guidelines that consider crop yield goals and management history were on the average 41 kg/ha (SD = 53 kg/ha) higher than would have been needed to achieve economic optimum yields in these experiments. This is much less precise than desired, but recommendations in effect prior to changes induced by results from these N fertilizer response experiments would have been 94 kg/ha (SD = 53 kg/ha) more than needed for economically optimum yields.
Characteristics and Geomorphic Relationships of Some Representative Aridisols in Southern Iran
Authors: Gharaee Hossein A. , Mahjoory Ramez A. 
Published: July 2010

AbstractThe morphology, genesis, and classification of three soils, each located on different physiographic positions, were investigated in southern Iran. These soils were: pedon 1, Beyza series on the Piedmont Alluvial Plain; pedon 2, Takht‐E‐Jamshid (Persepolis) series on the Upland Alluvial Plain; and pedon 3, Kooshkak (Jamalabad) series on the Lowland Alluvial Plain. These series represent 57% of the total study area (77 000 ha). The soils are calcareous throughout with carbonate concretions, nodules, and powdery pockets present in pedons 2 and 3. Clay skins are indicated in the B horizons of pedon 2. Soil pH rises from the Piedmont to the Lowland Alluvial Plain whereas organic matter decreases. Electrical conductivity does not show a regular trend from the Piedmont to the Lowland Alluvial Plain. Results of X‐ray diffraction analyses of < 2 µm clay indicate that the soils contain regularly interstratified smectite‐vermiculite and/or chlorite, clay mica‐vermiculite or chlorite, and some discrete vermiculite, chlorite, clay mica, kaolinite, and quartz. Evidence for attapulgite is also suggested. Tentatively, pedon 1 is classified as a Fluventic or Xerollic Camborthid; pedon 2a Xerollic or Typic Calciorthid; and pedon 3 a Xerollic Haplargid or Calciorthid.
Susceptibility of Agricultural Soils to Interrill Erosion
Authors: Meyer L. D. , Harmon W. C. 
Published: July 2010

AbstractSoil losses from crop row sideslopes were evaluated for 18 soils in a bare, tilled condition to determine their relative susceptibilities to interrill erosion. Erodibilities varied by a ratio of > 10:1 for the initial run and by 4:1 for succeeding runs. The poorly aggregated high‐silt soils were most erodible, and the high‐clay soils were least erodible. Simple correlations of interrill erosion with various soil properties were determined. Erosion was best correlated with clay (<2 µm) percentage, 1500 kPa water, exchangeable calcium, sum of exchangeable bases, cation exchange capacity, and organic matter content, all negatively. Interrill erosion was well correlated (positively) with the site specific K‐factor of the universal soil loss equation.
Comparing Soil Tests for a Forested Acid Sandy Soil Topdressed with Sewage Effluent
Authors: Fiskell J. G. A. , Rebertus R. , Comerford N. B. , Pritchett W. L. 
Published: July 2010

AbstractMobility of nutrients and heavy metals from mineralization of sewage sludge in acid soils is an environmental concern. Chemical properties of a forested acid sandy soil on flat terrain were examined at 6 and 30 months after ceasing multiple spray applications of sewage effluent. Total dry sludge applied was 5 and 26 Mg ha−1 on the treated 3‐ by 15‐m portion of 9‐ by 15 m plots. Less than 1.1 mg L−1 of either NO‐3‐N or PO3‐4‐P was found at the 24‐ to 90‐cm depth in soil solution extracted from the untreated bed adjacent to the planting area during 144 days. Treated areas were sharply defined by the growth of indigenous dog fennel (Eupatorium sp.) which was the dominant species. Mean soil pH was below 4.7 at 6 months and 5.1 at 30 months. Treated interbed Cd, Cu, and NH+4‐N were higher with depth at 30 months than 6 months while the reverse held for PO3‐4‐P. Untreated bed or interbed soils had lower soil test values than corresponding treated soils. Much higher metal values were found at the 7‐cm depth than deeper. Differences in metal extracted from treated and untreated soils were readily distinguished by DA (Mehlich I), DTPA‐TEA, and EDTA‐AA soil test methods. All three methods extracted from 25 to 75% of the metals applied in the sludge. Lack of more downward movement of N, P, and metals was attributed to slow mineralization of the sewage sludge.
Spatial Variability of Field‐Measured Denitrification Gas Fluxes
Authors: Folorunso O. A. , Rolston D. E. 
Published: July 2010

AbstractThe structure and magnitude of the spatial variability of N2O and N2O + N2 fluxes were investigated along 12 transects of a Yolo loam (Typic Xerorthents) field site. The field‐measured N2O and N2O + N2 fluxes were In‐normally distributed and exhibited large spatial variability. Calculated coefficients of variation ranged from 161 to 508% for the N2O + N2 fluxes and 282 to 379% for the N2O fluxes. Analysis of autocorrelograms and partial autocorrelograms showed that in only 1 transect out of the 12 did the N2O and N2O + N2 fluxes reveal any spatial dependence indicative of an autore‐gressive process. Thus, the denitrification flux values for this field site are considered to be spatially independent. With a knowledge of the frequency distribution and variances of the measured gas fluxes, it was calculated to require from 156 to 4117 N2O + N2 flux measurements and 350 N2O flux measurements to estimate the “true” mean flux within ±10% of the estimated mean on a 3 by 36 m experimental plot.
Sorption of Cadmium by Calcareous Soils: Influence of Solution Composition
Authors: O'Connor G. A. , O'Connor Candice , Cline G. R. 
Published: July 2010

AbstractCadmium sorption‐desorption by three Ca‐saturated, calcareous soils was studied in the presence of various Ca salts. Cadmium retention was extensive in all soil‐solution systems and was best characterized by a two‐part Freundlich relationship. Part I of the isotherm was interpreted to represent Cd retention by highly Cd‐specific adsorption sites, while part II of the isotherm represented a mixture of highly Cd‐specific and nonspecific adsorption sites. This interpretation was supported by desorption data. Differences in Cd sorption from various Ca solutions were at least partially rationalized by considering free Cd2+ activities as predicted by GEOCHEM. Additional consideration, however, must be given to complementary (competing) ion activities.
Applicability of the Four‐Probe Technique under Extremely Variable Water Contents and Salinity Distribution
Authors: Nadler A. , Frenkel H. , Mantell A. 
Published: July 2010

AbstractA drip‐irrigated cotton field was used to test the applicability of the four‐probe technique for measuring the salinity of the soil solution. The formation factor (F), which relates measured bulk soil electrical conductivity (ECa) to calculated salinity (ECw), is highly dependent on soil water content. Good results were obtained even though soil water content is extremely variable in drip‐irrigated soil. Only 15% of the calculated salinity values deviated from a range chosen as a reasonable criterion (± 20% of water‐content‐corrected soil extracts), and this deviation was attributed to an unrepresentative water content value of the sampled soil. The calculation procedures produced similar values when slightly different parameters were used in calculating ECw from ECa.
Bicarbonate Directly Induces Iron Chlorosis in Susceptible Soybean Cultivars
Authors: Coulombe B. A. , Chaney R. L. , Wiebold W. J. 
Published: July 2010

AbstractFour soybean [Glycine max (L.) Merr.] cultivars differing in susceptibility to iron (Fe) chlorosis in wet calcareous soils were grown in nutrient solutions to characterize the effects of phosphate (P) and bicarbonate (HCO‐3) in inducing chlorosis. NaHCO3 (0 or 10 mM), P (10 or 400 µM as NaH2PO4, and NH+4 (0 or 300 µM) as (NH4)2SO4 were factorial treatments in a nutrient solution. Low Fe availability was maintained by supplying 5 µM Fe + 10 µM EDDHA, and excess CaCO3(pH 7.5). With no HCO‐3 added, ‘T203’ (extremely chlorosis susceptible) was green at 10 µM P, but severely chlorotic at 400 µM P; ‘Wayne’ (chlorosis susceptible) was green at both P levels. Addition of HCO‐3 caused chlorosis in T203 and Wayne at 10 or 400 µM P. Chlorosis resistant ‘AP9’ and ‘Hawkeye’ remained green with added P or HCO‐3. Chlorosis ratings (1 = green to 5 = severely chlorotic) in the 0 HCO‐3 + 10 µM P, 0 HCO‐3 + 400 µM P and 10 HCO‐3 + 400 µM P treatments, respectively, were: 1.0, 1.0, and 1.5 for AP9; 1.0, 1.0, and 1.4 for Hawkeye; 1.0, 1.2, and 3.9 for Wayne; and 1.0, 4.2, and 4.6 for T203. Low Fe concentrations in young leaves corresponded with high chlorosis ratings. Phosphorus concentration in young leaves did not change with HCO‐3 at 10 µM P, but decreased with HCO‐3 at 400 µM P. In the absence of HCO‐3, Wayne was not chlorotic at either concentration of solution P, although this cultivar is known to be highly susceptible to chlorosis in the field. Bicarbonate‐induced chlorosis in Wayne was not a result of increased solubility or plant uptake of P. Thus, HCO‐3 was a direct factor in causing soybean chlorosis, and likely is also a cause in soils.
Effects of Water and Salt Stress on Growth and Acetylene Reduction in Alfalfa
Authors: Keck T. J. , Wagenet R. J. , Campbell W. F. , Knighton R. E. 
Published: July 2010

AbstractThe interactive effects of three irrigation water salinities (1.0, 3.0, and 9.0 dS/m) and three quantities of water applied per irrigation (2.3, 4.7, and 7.0 cm) on plant growth and N fixation by alfalfa (Medicago sativa L. cv. Resistador) were assessed in the greenhouse. Salt and water treatments were started after nodulation had been established in young plants and samples were harvested at 10, 30, and 50 d thereafter. Alfalfa top growth was limited by both salt and water stresses. Irrigation water salinity had a greater effect on top growth than root growth while root distribution was unaffected by either the quantity of water applied or by water salinity. The effects of salinity on plant growth were masked by water stress. Specific nodule activity (µmol C2H4 s−1 kg−1) was enhanced by increasing quantity of water applied at each irrigation and was adversely affected by increased irrigation water salinity. In contrast, both nodulation and total nodule mass were insensitive to salt stress and sensitive only to severe water stress. Alfalfa plants continued to reduce acetylene at the third sampling even under severe water and salt stress. These data indicate that the Resistador cultivar of alfalfa apparently continues to fix N2 during periods of substantial environmental stress.
Fiber Size Distribution, Bulk Density, and Ash Content of Peats in Minnesota, Wisconsin, and Michigan
Authors: Nichols Dale S. , Boelter Don H. 
Published: July 2010

AbstractBoelter (1969) described the physical characteristics of some undrained organic soils in northern Minnesota. This paper expands upon Boelter's work. Bulk density, ash content, and percent (dry weight basis) of rubbed and unrubbed fiber > 2.0 mm, 1.0 – 2.0 mm, 0.5 – 1.0 mm, 0.25 – 0.5 mm, and 0.1 – 0.25 mm were determined for 176 peat samples from 38 peatlands in northern Minnesota, Wisconsin, and the Upper Peninsula of Michigan. When the distribution of various sizes of plant fibers in the peat is used as an index of the stage of peat decomposition, the increase in bulk density that accompanies increasing decomposition is easily seen. Fibers > 0.5 mm predominate in low bulk density peats, but are quickly lost as decomposition proceeds and bulk density increases. Curvilinear regression equations between bulk density and rubbed and unrubbed fiber >0.5, >0.25 and 0.1 mm were developed that represent improvements over such equations previously calculated for northern Minnesota peats only. At the same bulk density, moss peats contained larger amounts of fiber than herbaceous peats; the unrubbed fiber content of the woody peats studied was higher than that of moss peats, but fell to an intermediate level between moss and herbaceous peats when subjected to rubbing. When a dispersing agent such as sodium metaphosphate (NaPO3) is used before sieving and percent fiber is calculated on a dry weight basis, the traditional rubbed fiber content appears to have little advantage over unrubbed fiber content as a descriptive criterion for characterizing organic soil.
Soil Survey Interpretations from Water Retention Data: II. Assessment of Soil Capability Ratings and Crop Performance Indices
Authors: McBride R. A. , Mackintosh E. E. 
Published: July 2010

AbstractA water retention model developed for Ontario soils is used to estimate the preseason plant‐available moisture‐holding capacity (Θva) of the soil root zone in equilibrium with a phreatic surface and the air‐filled porosity (ε) of the surface 30 cm. Preliminary soil capability class ratings are then assessed from a set of regional guidelines based on class intervals of Θva and ε. Crop performance indices are determined for capability classes 1 to 5 inclusive using a statistical corn productivity model which relates long‐term mean grain corn yields in Ontario to a seasonal soil moisture deficit or surplus. Total seasonal field water supply is budgeted against potential crop evapotranspiration to estimate the extent to which plant water stress from excess or deficit soil water availability limits the attainment of regional agro‐climatic potential yields. Advantages in using a water retention model as a basis for agronomic interpretations of soil survey data for land evaluation purposes are discussed.
Fragipan Bonding in a Late‐Wisconsinan Loess‐Derived Soil in East‐Central Ohio
Authors: Norton L. D. , Hall G. F. , Smeck N. E. , Bigham J. M. 
Published: July 2010

AbstractA fragipan developed in a late‐Wisconsinan, loess‐derived soil was studied in detail to determine if its brittleness could be related to a specific chemical bonding agent. Three approaches were used in the study. The first involved an attempt to create fragipan brittleness and consistence by adding solutions containing Fe, Al, or Si to non‐fragipan, loess material. Secondly, a destructive approach utilizing various dissolution techniques was used to extract fragipan material under vacuum in an attempt to selectively remove the cementing agent. Lastly, the fragipan fabric was observed and analyzed in situ by scanning electron microscopy (SEM) and energy dispersive X‐ray analysis (EDXRA). Solutions containing Si or Al added to acid, nonfragipan loess material increased the rupture strength. Na‐citrate‐bicarbonate‐dithionite (CBD) and Na‐citrate‐dithionite solutions destroyed fragipan peds under vacuum and eliminated the slaking properties of the residue. Pyrophosphate also destroyed the ped fabric and dispersed clay, but the residue retained its ability to slake in water. Differential infrared spectroscopy and differential thermal calorimetry revealed that CBD selectively removed an inorganic fraction unique to the fragipan. SEM study demonstrated that bridges occurred between silt grains in the fragipan and EDXRA revealed that these bridges contained considerably more Si than identifiable argillaceous plasma in either the fragipan or nonfragipan horizons. In conclusion, the key bonding agent in the fragipan studied appears to be a hydrous aluminosilicate, possibly associated with clay, which formed bridges between skeletal grains.
Genesis and Morphology of Soils Associated with Formation of Laramie Basin (Mima‐Like) Mounds in Wyoming
Authors: Spackman L. K. , Munn L. C. 
Published: July 2010

AbstractSmall mounds of varied origin are a common microrelief feature over much of the western United States. In Wyoming's Laramie Basin, soil genesis and mound formation were studied in a 27.5 m long trench dug to expose intermound soils with strongly developed horizonation (Borollic Haplargids) and two mounds with weakly developed soils (Borollic Camborthids). Fossil permafrost sand wedges, common along the trench exposure, are believed to be evidence of a mid‐ to late‐ Wisconsin periglacial environment. The intermound soils date from pre‐ to early Wisconsin and were formed by a sequence of alluvial deposition, argillic horizon development, carbonate accumulation, sand wedge formation, and development of a second argillic horizon with weak carbonate accumulation. Mound formation occurred as a result of upwellings of gravelly substrata induced by cryostatic pressure. The gravelly pipes broke through large fossil sand wedges to the soil surface forming the mounds. Subsequent soil formation on the mounds has involved cambic horizon development, leaching of salts, and weak carbonate accumulation.
Statistical Analysis of Crop Yield‐Soil Water Relationships in Heterogeneous Soil under Trickle Irrigation
Authors: Russo David 
Published: July 2010

AbstractField data of bell pepper (Capsicum frutescens ‘Maor’) yield (Y), soil water pressure potential (P), and salinity (EC) obtained under trickle irrigation, and of two soil hydraulic parameters (K1 and α), were used to analyze spatial variability of these properties and its impact on relationships between crop yield and soil properties. Both conventional statistical analysis methods and spatial structure analysis methods were used. With the conventional methods, observations of each property were considered as statistically independent regardless of their spatial position in the field. Results of multiple regression analysis suggest the variability in K1 and α is responsible for about 25% of the variabilities in both P and EC, which in turn, are responsible for < 25% of the variability in Y, when experimental data from the entire field are considered. With the spatial structure methods, a variogram was used to investigate spatial structure of different properties, and a cross‐variogram was used to investigate spatial dependence of P and EC on K1 and α and spatial dependence of Y on P and on EC. Results show field spatial structure affects the relationships between different properties over distances which were related to the respective ranges of direct variograms of pertinent properties. The characteristic length of field spatial structure (in terms of integral scale, J) varied between J = 25 m (K1) and J=78 m (α) with an average of J=43 m. The direct variograms of properties were used to calculate kriging estimates of pertinent properties, which in turn, were used for two subsequent analyses. In the first analysis, kriging estimates obtained for a square domain (43 by 43 m in size) moving over the entire field were used to calculate the correlation between different properties at different parts in the field. The analysis showed that in some parts of the field variability in K1 and α was responsible for about 90% of the variabilities in both P and EC, which in turn, were responsible for about 90% of the variability in Y. In the second analysis, kriging estimates of Y, P and EC obtained for regions in the field which are associated with a constant saturated zone in the vicinity of the trickle emitter (in terms of its radius ru = ru (K1, α; Q); Q being trickle emitter discharge) were used to analyze the dependence of Y on P and on EC. The analysis showed that in regions which were associated with relatively small values of ru (ru < 0.05 m) the variability in P and EC is responsible for > 0.8 of the variability in Y. In regions which were associated with relatively large values of ru (ru>0.08 m) and a relatively large leached zone, it was not soil water pressure or salinity, but other factors that most influenced yield.