bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of Ammonia Volatilization from Turkey Manure and Urea Applied to Soil
Authors: Nathan Manjula V. , Malzer G. L. 
Published: July 2010

AbstractField measurements of NH3 volatilization from both surface‐applied and incorporated turkey (Meleagris gallopavo) manure (20 g of N m−2, which compares with 16 Mg of manure ha−1) and urea (20 g of N m−2) were made using the forced‐draft technique for a 6‐d period in early June 1991. The soil (temperature and water potential) and atmospheric parameters (relative humidity, wind speed, and air temperature) affecting NH3 volatilization rate were also measured. Ammonia losses for manure and urea followed a diurnal pattern; maxima occurred shortly after midday (between 1200 and 1800 h), when soil temperature was nearing maximum and wind speed was highest, and minima occurred during midnight to early morning hours (between 2400 and 0600 h), when the soil temperature was lowest and relative humidity was highest. Significant positive correlations between rates of NH3 volatilization and soil temperature, atmospheric temperature, and wind speed were observed. Relative humidity was generally negatively correlated with NH3 volatilization. Ammonia volatilization from the surface‐applied manure was highest immediately after application and gradually decreased with time, whereas ammonia volatilization from surface‐applied urea did not start until Day 2 and reached a maximum on Day 6. The total NH3 loss from incorporated manure was 23 times lower than that from surface‐applied manure (0.5 vs. 11.5 kg of N ha−1), whereas NH3 loss from urea was eight times lower when incorporated (0.2 vs. 1.5 kg N ha−1) during a 6‐d period. Total N loss (6 d) from surface‐applied urea was eight times lower than an equivalent amount of inorganic N in turkey manure (1.5 vs. 11.5 kg of N ha−1). Ammonia volatilization from turkey manure and urea was found to be influenced by a combination of environmental factors and the method of application.
Effects of Soil Surface Management on Water Flow Distribution and Solute Dispersion
Authors: Poletika N. N. , Jury W. A. 
Published: July 2010

AbstractA known benefit of cultivation is increased infiltration rates during subsequent irrigation or precipitation events. This study was conducted to investigate the effects of cultivation and irrigation method on uniformity of water flow and dispersion of solutes leached through a Tujunga loamy sand (mixed, thermic, Typic Xeropsamment) at Etiwanda, CA. Outflow from undisturbed, unsaturated field soil contained in a 0.8 by 0.8 by 0.3 m lysimeter was sampled by a 64‐cell grid of fiberglass wick solution samplers. Daily 20‐mm water inputs were applied at a rate of 5 mm h−1 for 4 h by hydraulic spray nozzles (HSN) mounted on a motorized boom or by low‐volume sprinklers (LVS). Narrow pulse inputs of Cl−, NO−3, and Br− solutions were used to evaluate solute dispersion and travel paths. Four experiments were conducted sequentially in the same lysimeter: (i) light raking, broadcast Cl− and local NO−3, and HSN, (ii) light raking, local Cl−, HSN, (iii) shallow cultivation and releveling, no solute, and LVS, and (iv) broadcast Br− and HSN. Based on drainage positions observed with locally applied solutes, flow appeared to be one‐dimensional through most of the transport volume. Switching from HSN to LVS and then back to HSN apparently had much less effect on water‐flow variation than did shallow cultivation and releveling. The overall trend with time was decreasing variability in locally measured water flow, and only in the last experiment were the flow patterns time invariant. Areaveraged solute breakthrough curves for transport experiments conducted before and after cultivation showed less dispersion following cultivation. The decrease in solute spreading estimated from fitted convection‐dispersion model parameters and by travel time moment analysis was of similar magnitude to the reduced variation of the locally measured water flows. Shallow cultivation appeared to lower the hydrodynamic dispersion of the flow field at the scale measured in this study, thus decreasing the spreading of the leached solute pulse.
Hydraulic Flow and Water Quality Characteristics in Rill Erosion
Authors: Shainberg I. , Laflen J. M. , Bradford J. M. , Norton L. D. 
Published: July 2010

AbstractThe effects of interaction between water flow characteristics, soil sodicity, and water quality on the detachment of soil particles by flowing water was studied in the laboratory. Specific objectives of this study were to evaluate: (i) the use of flow shear stress and stream power for estimating soil detachment, (ii) the effect of low soil sodicity (exchangeable sodium percentage [ESP] <10) and water quality (deionized water [DW] and 0.005 M CaCl2 solution [TW]) on soil detachment, and (iii) the effect of negatively charged polyacrylamide (PAM) polymer on soil detachment. Detachment rates were measured in a small hydraulic fume. Several bed slopes and flow rates were studied. Detachment rate increased linearly with both shear stress and stream power of the flow. The rill erodibility of the Miami soil (fine‐loamy, mixed, mesic Typic Hapludalf) agreed well with field data. Water quality had no effect on rill erodibility for the soil tested when ESP < 3.0. Use of TW reduced the erodibility of soils with ESP 5 and 10 compared with DW. Surface treatment with PAM (0.05 g m−2) prevented soil detachment in flows with high shear stress. The formation of a surface soil layer with high cohesion and aggregate stability prevented soil detachment. Soil surface properties and not bulk soil properties determined soil detachment.
Organic and Conventional Management Effects on Biologically Active Soil Organic Matter Pools
Authors: Wander M. M. , Traina S. J. , Stinner B. R. , Peters S. E. 
Published: July 2010

AbstractSpecific impacts of organic management practices on soil organic matter characteristics have not been documented. This study tested how organic management practices influence soil fertility by investigating whether 10 yr of organic or conventional management generated differences in biologically active soil organic matter (SOM) pools at the Rodale Institute Research Center's long‐term Farming Systems Trial experiment (FST). The experiment included an organically managed rotation that was animal based, an organic treatment that was cash‐grain based, and a conventional cash‐grain‐based rotation. The biologically active SOM matter pools of the three FST treatment soils were compared through characterization of soil CO2 evolution, available inorganic N pools and N mineralization rates, water‐dispersible organic carbon (WDOC), and particulate organic matter (light fraction). Soils receiving the organic treatments accumulated biologically active C. Accumulated organic matter in the manureamended soil was the most labile whereas the cover‐cropped soil accumulated the most organic matter overall. In the cover‐cropped soil, higher total C and N, particulate SOM, and reduced WDOC contents indicated that its SOM was more stable than SOM in the other two treatment soils. The conventionally managed soil had the lowest biological activity (N supply and soil respiration rates) and did not accumulate SOM during the 10‐yr experiment. Assays that characterize particulate organic matter emerged as the best indices of biologically active SOM because they documented important quality (i.e., biological lability) and quantity aspects of SOM character in the Rodale FST soils.
Carbon Turnover in Soil Physical Fractions
Authors: Buyanovsky G. A. , Aslam M. , Wagner G. H. 
Published: July 2010

AbstractSoil organic matter (SOM) as represented in mathematical simulation models involves several hypothetical pools of differing resistance to decay. These conceptual pools satisfy requirements of modeling, but usually have little in common with existing information on physical and chemical properties of SOM. Using our data on turnover times for soil C in fractions of natural aggregates and primary particles, we attempted to relate age of C in physical fractions with that in widely accepted theoretical pools. Soil from a field experiment with 14C‐labeled soybean residues was sampled periodically and separated into physical fractions. The amounts of 14C associated with these fractions at different times provided data for calculation of decay rates and turnover times. The most labile fraction of SOM was plant fragments with turnover time ranging from 1 to 3 yr, which was inversely related to fragment size. Soil aggregates were found to be enriched in C compared with whole soil. This was most pronounced for coarser aggregates whose construction apparently involved the relatively labile plant fragments in some progressive state of decay. The macroaggregates with partially processed C showing turnover from 1 to 3 yr contrasted with microaggregates that included more highly humified C having a longer residence time of ≈7 yr. Various soil fractions differing in residence time of associated C were assembled into several groups that demonstrated consistency with conceptual pools of two widely accepted simulation models. Data from 13C natural abundance studies of soil and of primary fractions were in harmony with models requiring at least two pools of stable SOM.
Sealing, Amendment, and Rain Intensity Effects on Erosion of High‐Clay Soils
Authors: Reichert José Miguel , Norton L. Darrell , Huang Chi‐hua 
Published: July 2010

AbstractThe physicochemical composition of and processes acting on the soil‐fluid interface determine detachment and transport of soil particles by erosive forces at the surface during rain. It is hypothesized that fluidized bed combustion (FBC) bottom ash and soil surface condition change the relationship between rain intensity and runoff and sediment yield. On small erosion pans, aggregates from five clayey soils (Alfisol, Oxisol, Ultisol, and Vertisols) with distinct swelling and flocculation characteristics were subjected to simulated rainfalls of 74, 39, and 107 mm h−1 for 90, 30, and 30 min, respectively. This rain sequence was applied on freshly tilled (FT), dried‐crust (DC) and wet‐crust (WC) soil. Fluidized bed combustion bottom ash was spread on FT soil at a rate of 5 Mg ha−1. Power functions described well sediment yield as a function of rain intensity, with exponents of 1.97 for FT, 1.74 for DC, and 1.72 for WC; thus as the soil sealed and consolidated, rain intensity influenced the erosion rates less. Dried‐crust was the most erodible surface for half of the soils. Clay shrinkage disrupted aggregates and preformed crusts, whereas rewetting caused differential swelling and raindrops pitted the soil surface. Runoff decreased from FT to DC, but no increase was observed from DC to WC. Smectitic and illitic soils had a longer‐lasting positive effect of FBC bottom ash on reducing soil and water losses. For the highly smectitic Vertisols, FBC bottom ash was effective on reducing erosion even after 552 mm of rain. Kaolinitic soils were more stable, generating lower runoff and soil loss rates.
Soil Drainage Class Effects on Early Response of Balsam Fir to Precommercial Thinning
Authors: Briggs Russell D. , Lemin, R. C. 
Published: July 2010

AbstractPrecommercial thinning (PCT), a silvicultural treatment commonly used to increase individual tree growth rate and reduce the time required to attain merchantability for young fir (Abies spp.)‐spruce (Picea spp.) stands, is both biologically effective and expensive ($300–500/ha in 1993). Forest managers desire to allocate silvicultural capital to maximize return on investment. This study was initiated to identify criteria that could be utilized to rank sites according to response of balsam fir [Abies balsamea (L.) Mill.] to PCT. Sixty‐two plots were established in young fir‐spruce stands in Maine that had been precommercially thinned between 1977 and 1987. Volume increments 3 yr prior to (VI3PRE) and 3 yr after (VI3POST) PCT were reconstructed from detailed stem analyses of 427 balsam fir trees. Increased radial increment following PCT was visually apparent and significant for each sample tree. The magnitude of the response was strongly affected by soil drainage class. Regression with dummy variables showed that VI3POST, expressed as a function of VI3PRE, increased as soil drainage class improved from poorly (mottling within 10 cm of mineral soil surface) to well (mottling >60 cm below mineral soil surface) and somewhat‐excessively drained (loam textured cap overlying deep sand), then decreased for trees growing on excessively drained (sandy‐textured) soils. Soil drainage class can be used effectively to rank sites according to expected response to PCT on large land bases.
Fertilizer Nitrogen Requirements for Cotton Production as Affected by Tillage and Traffic
Authors: Torbert H. A. , Reeves D. W. 
Published: July 2010

AbstractSoil compaction and its associated problems have led to interest in investigating the interactive effects of traffic and tillage systems on fertilizer N requirement for cotton (Gossypium hirsutum L.). In 1987, a study was initiated on a thermic Typic Hapludult soil complex with a cropping system of wheat (Triticum aestivum L.)‐cotton double cropped. The experimental design was a split‐split plot with four replications. Main plots were two traffic treatments (conventional and no‐traffic), subplots were four tillage systems for cotton (surface tillage without subsoiling [surface‐only], surface tillage and annual in‐row subsoiling [subsoiling], surface tillage with one‐time‐only complete disruption of the tillage pan [complete], or no surface tillage and in‐row subsoiling [strip‐till]), and sub‐subplots were four N rates (0, 45, 90, and 135 kg N ha−1). In addition, application of 15N‐labeled NH4NO3 was made to microplots inside each tillage‐traffic‐90 kg N ha−1 plot. In 1990 and 1991, increasing N application increased cotton biomass and decreased lint percentage. In the dry year of 1990, no‐traffic decreased seed cotton yield from 1500 to 1360 kg ha−1, while tillage had no significant effects on cotton yield components. Above‐normal rainfall in 1991 resulted in the strip‐till with no‐traffic treatment having the highest seed cotton yield (2749 kg ha−1) and the greatest fertilizer N uptake efficiency (35%). Results indicate that the detrimental effects of traffic on N uptake efficiency may be reduced with conservation tillage systems and that higher fertilizer N application rates may not be needed for conservation tillage practices such as strip‐till in Coastal Plain soils.
Root‐Zone Mineral Nitrogen Changes as Affected by Crop Sequence and Tillage
Authors: Meek B. D. , Carter D. L. , Westermann D. T. , Peckenpaugh R. E. 
Published: July 2010

AbstractCrop sequence and tillage affect soil mineral N (NH4 plus NO3) and NO3 leaching below the root zone following alfalfa (Medicago sativa L.). A 2‐yr field experiment was conducted in south‐central Idaho to determine the effect on soil NO3 levels of a corn (Zea mays L.)‐wheat (Triticum aestivum L.) rotation compared with a bean (Phaseolus vulgaris L.)‐bean rotation and to demonstrate improved N utilization with a corn‐wheat rotation. Alfalfa, growing on an irrigated Portneuf silt loam (coarse‐silty, mixed, mesic Durixerollic Calciorthid), was killed in October 1989 with herbicide. Treatments were: (i) BT‐BT: conventional tilled bean grown in 1990 and 1991; (ii) CNT‐WNT: no‐till silage corn grown in 1990, and no‐till winter wheat grown in 1990–1991; and (iii) CT‐WT: same as CNT‐WNT but under conventional tillage. Similar amounts of soil N were mineralized the first (275 kg N ha−1) and second (213 kg N ha−1) year after killing the alfalfa in all treatments. The BT‐BT treatment had the highest growing‐season soil mineral N (up to 251 kg ha−1, 0–0.45‐m depth) because the N uptake by bean was lower (187 kg N ha−1) than corn (252 kg N ha−1, average of CT‐WT and CNT‐WNT treatments) in 1990 and later than winter wheat uptake in 1991. Most wheat N uptake had occurred by late June when bean uptake was just starting. A rotation that follows alfalfa with corn or a crop with a similar N uptake pattern, instead of bean, will save N fertilizer, lower soil NO3 levels, and reduce NO3 leaching potential.
Fluidized Bed Bottom‐Ash Effects on Infiltration and Erosion of Swelling Soils
Authors: Reichert José Miguel , Norton L. Darrell 
Published: July 2010

AbstractFluidized bed combustion (FBC) bottom ash, rather than being used as fill at dumping sites, can be utilized to amend certain soils for erosion control. Because FBC bottom ash is a source of both electrolytes and alkalinity, its effectiveness in controlling runoff and erosion should be greater on soils with a predominance of permanent charges. Five soils, with and without addition of 5 Mg ha−1 surface‐applied FBC bottom ash, were prewetted and subjected to 110 mm h−1 rain for 90 min. The critical flocculation concentration (CFC) varied from 0.5 mmolc L−1 for the smectitic‐kaolinitic soil to 3.5 mmolc L−1 for the illitic soil. Steady‐state infiltration rates (Is) for the control were very low, ranging from 1.8 to 5.8 mm h−1. These rates were increased 3.6‐ to 5.0‐fold with the application of FBC bottom ash, with a lesser increase for the highly smectitic and illitic soils. For the control, total soil loss ranged from 220 to 1998 g m−2, and total water loss from 78 to 112 mm, with the greatest losses for soils with a large cation‐exchange capacity/clay ratio. The FBC bottom ash reduced total water loss by 1.1‐ to 2.0‐fold and total soil loss by 1.5‐ to 3.9‐fold. The CFC of the soil was correlated with Is, while aggregate stability was correlated with erosion and total runoff. The FBC bottom ash effectiveness in increasing infiltration and controlling erosion on these soils is attributed to an increase in electrolytes in the runoff, thus decreasing soil swelling and the dispersion of clay platelets and preventing surface sealing.
Temporal Variability of Selected Properties of Loessial Soil as Affected by Cropping
Authors: Scott H. D. , Mauromoustakos A. , Handayani I. P. , Miller D. M. 
Published: July 2010

AbstractQuantification of the relationships between short‐ and long‐term variability of soil properties is needed to understand the effects of cropping on soils. These relationships were studied in four adjacent fields of a Typic Albaqualf or a Typic Glossaqualf which included a prairie and three fields that had been cropped for 3, 14, or 32 yr. The fields were sampled monthly from March 1989 to March 1990. Soil samples were collected at depth intervals of 0 to 5 cm and 5 to 10 cm at each sampling time. The statistical model assumed that the fields studied represented a random sample of fields from a large population. One of the ways in which these fields differ is in cropping duration. Field and sampling time variabilities were treated as random effects in a mixed model including soil depth. We defined the variability among fields as long‐term and the variability among sampling times within a field as short‐term. Statistical analyses indicated that the soil properties vary with cropping, depth interval, and sampling time within a year. The highest ratio of long‐ to short‐term variability (r) was found to be 26 with total C, and the lowest ratio was 0.52 with saturated hydraulic conductivity (Ksat). Values of r for most of the soil properties examined ranged between 1.7 and 2.8 and tended to be higher in the first depth interval. The large estimated standard errors for these ratios indicated that even though r was greater than 1.0, the long‐term variability was not statistically significantly greater than the short‐term variability at α = 0.05.
Seasonal Preferential Flow in Two Sierra Nevada Soils under Forested and Meadow Cover
Authors: Burcar S. , Miller W. W. , Tyler S. W. , Johnson D. W. 
Published: July 2010

AbstractThe preferential movement of surface‐applied solutes is a potential source of groundwater contamination and could subsequently provide a major source of nutrients to Lake Tahoe. This study investigated seasonal infiltration, water repellency, and preferential water flow in two Sierra Nevada soil types (a granitic and a volcanic soil) in forest and meadow areas using a rainfall simulator. Infiltration and runoff were measured at the plot surface. Plots were subsequently excavated to measure preferential water flow. Water repellency was found to affect infiltration and nonuniform preferential flow was observed. The volcanic soil demonstrated continuous preferential flow with depth, whereas in the granitic soil, preferential flow rapidly dissipated. Wetting patterns showed greater preferential flow in the forested areas for both soils compared with the meadow areas. Higher initial water content and reduced water repellency in the early spring generally produced more typical matrix water flow in the coarser textured granitic soil. Since preferencial flow was most evident in all forested conditions, nutrient bypass potential is considered greatest on soils in forested areas near tributaries and the lake.
Cobalt, Cadmium, and Lead Sorption to Hydrous Iron Oxide: Residence Time Effect
Authors: Ainsworth Calvin C. , Pilon James L. , Gassman Paul L. , Van Der Sluys William G. 
Published: July 2010

AbstractThe adsorption‐desorption of the divalent metal cations (Me2+) Co2+, Cd2+, and Pb2+ to hydrous ferric oxide (HFO) was investigated as a function of oxide aging and Me2+‐oxide residence time. The HFO was produced and stored for up to 86 wk. Periodically, Me2+ sorption was determined across the pH range of 2.5 to 12. In addition, the Me2+ ions were contacted with freshly produced HFO and stored at a pH that dictated that 80 to 100% of the Me2+ would be in the sorbed state; desorbability of the Me2+ was determined as a function of Me2+‐oxide residence time. The change in the crystallinity of the HFO as a function of time was also monitored. The HFO aged without the Me2+ ions displayed no hysteresis between the adsorption‐desorption curves and no substantial shifts in fractional Me2+ adsorption were observed with pH throughout 21 wk of aging. The HFO aged with the Me2+ ions displayed increasing desorption hysteresis with time for Co2+ and Cd2+, but not Pb2+. The magnitude of hysteresis followed the order Co > Cd > Pb, which is the inverse of the ionic radii of the metal sorbates. While oxalate‐extractable Fe decreased with time during a 20‐wk period, powder x‐ray diffraction was unchanged during the same period. The data presented here suggest that Co and Cd are being incorporated into the metal oxide structure via recrystallization, but Pb remains associated with the surface and excluded from incorporation.
Solute Partitioning in a Calcium Carbonate‐Phosphoric Acid‐Water System
Authors: Salingar Yigal , Kochva Malik 
Published: July 2010

AbstractA range of Ca phosphates form in a time‐dependent process, when calcite interacts with a dilute orthophosphate solution. This study was conducted to ascertain the possible formation of a stable CaCO3‐PO4 compound on calcite surfaces and to characterize its precursors. The solution's ionic speciation provided evidence of the formation of a CaHCO3‐PO4 compound (CBP) with a stoichiometric Ca/P ratio of 3 and a solubility product, Ksp, of (Ca2+)3(HCO−3)3(PO3−4) = 10−28.36. This hypothesis was also supported by electron spectroscopy analyses of the surface layers of the final solid product and scanning electron microscopy (SEM). Prior to the CBP formation, either a compound with the same Ca/P ratio as dicalcium phosphate (DCP, CaHPO4) formed, or CBP was in quasi‐equilibrium at a Ca/P ratio of 1.5 to 2.3. Another possibility is that a poorly crystalline or amorphous Ca phosphate solid phase was formed. Finally, the newly formed CBP converted to hydroxyapatite (HAP, Ca5 (PO4)3OH).