Lee Sommers

• PhD
• Professor Emeritus at Colorado State University

Total carbon (C) in soils is the sum of both organic and inorganic C. Organic C is present in the soil organic matter fraction, whereas inorganic C is largely found in carbonate minerals. The wet combustion analysis of soils by chromic acid digestion has long been a standard method for determining total C, giving results in good agreement with dry...

The extraction and quantitation of sewage sludge proteins is a prerequisite to evaluating their role as labile C and N sources in sludge- amended soil. The objective of this study was to develop extraction methodology for the routine quantitation of sewage sludge proteins. Seven sewage sludges were obtained and prepared by oven drying at 55 °C foll...

The characterization of sewage sludge proteins is necessary to better understand their degradation by microbial populations when sludges are utilized for land application. The objective of this study was to characterize the molecular weights of extractable sewage sludge proteins by dialysis partitioning and polyacrylamide gel electrophoretic (PAGE)...

A laboratory incubation study of seven sewage sludges was initiated to test the hypothesis that sewage sludge proteins are labile C and N sources. Proteins were extracted and determined by the Lowry assay. Sewage sludges were mixed with Bresser sandy loam soil (Aridic Argiustoll) at a rate of 10 g dry sludge kg-1 dry soil and incubated at 25°C to d...

Mountain meadows near Leadville, CO, were contaminated with trace metals through the deposition of hydraulically transported mine tailings in the early 1900s. A study was conducted to: (I) characterize the physical and chemical properties of contaminated soils, (II) determine the soil depth distribution of total, organically bound, oxide-bound, exc...

In an attempt to reduce ammonia (NH3) losses from surface applied urea to ultimately increase plant N use efficiency, a field experiment was conducted to compare the effects of six phosphoroamide urease inhibitors on NH3 volatilization from urea surface applied to no-till (NT) and conventionally tilled (CT) soils. Urea prills with and without phosp...

American Society of Agronomy Division A‐5, Environmental Quality, was established in 1971. Its original purpose as a separate division was to allow grouping of papers on environmental issues at the ASA annual meetings. Concurrently, a new journal, Journal of Environmental Quality (JEQ), was established (1972) to (i) provide a focus on environmental...

A field experiment compared the ability of several phosphoroamide compounds to retard urea hydrolysis on a fallowed notill (NT) and conventionally tilled (CT) silt loam soil (pH 5.70). Treatments consisted of urea prills (200 kg N ha-1) with and without inhibitors (4.0 kg ha-1) and a no-fertilizer check. Fertilizers were surface-applied to 10-cm-di...

Phosphoroamide urease inhibitors were evaluated for their ability to increase grain protein and yield of winter wheat (Triticum aestivum L.) when added to surfaceapplied urea-based fertilizers. Six urease inhibitors [trichloroethyl phosphorodiamidate, diethyl phosphoric triamide, dimethyl phosphoric triamide, N-(diaminophosphinyl)-cyclohexylamine,...

The kinetics of glucose uptake by soil microorganisms was investigated. Soil amended with an inorganic nutrient solution containing C glucose at concentrations of 2.5, 5.0, 10.0 or 20.0 mmol 1−1 was maintained at 4, 12 or 25°C for varying times. The soil was analyzed for glucose, soluble 14C, total organic 14C and evolved 14CO2 to develop a carbon...

Phosphoroamide urease inhibitors were evaluated for their ability to increase N uptake and grain yield of corn (Zea mays L.) when added to surface-applied urea fertilizers. Six urease inhibitors [trichloroethyl phosphorodiamidate, diethyl phosphoric triamide, dimethyl phosphoric triamide, N-(diaminophosphiny1)-cyclohexylamine, N-benzyl-N-methyl pho...

Two computer programs based on simultaneous chemical equilibria were compared for calculation of chemical species in xylem exudates. The first program, CHELATE, was developed to calculate the chemical species in xylem exudates while GEOCHEM was developed to calculate the speciation of natural aquatic systems. The output of the two programs should b...

Cadmium and Zn were characterized in soils treated with 100 Mg ha-1 of an anaerobically digested sewage sludge from Chicago, IL. The four soils included a Chalmers silt loam (Typic Haplaquolls) (Indiana), Celina loam (Aquic Hapludalfs) (Michigan), Celina silt loam (Aquic Hapludalfs) (Ohio), and a Plano silt loam (Typic Aquidolls) (Wisconsin). The s...

To evaluate models for predicting plant uptake of Zn and Cd, a growth chamber study was conducted with soils collected from research plots in Ohio, Indiana, Michigan, and Wisconsin that had been treated 4 yr previously with 100 Mg ha-1 of an anaerobically digested sewage sludge from Chicago, IL. The single application of sludge supplied 19-kg Cd an...

Cadmium and zinc uptake parameters were determined for intact corn (Zea mays L.) seedlings grown for 15 and 22 in nutrient solutions containing levels of Cd and Zn that were similar to those found in soil solutions. Uptake of both elements was assumed to follow Michaelis-Menten kinetics. Calculations were based on the concentrations of free ionic C...

Relationships between structure and biodegradability were evaluated for 28 pyridine derivatives in nutrient solutions inoculated with soil and incubated at 24°C. Compounds studied included pyridine; mono- and disubstituted pyridinecarboxylic acids; and hydroxy-, chloro-, amino-and methylpyridines. Disappearance of the pyridine added was measured by...

An organism capable of growth on pyridine was isolated from soil by enrichment culture techniques and identified as Micrococcus luteus. The organism oxidized pyridine for energy and released N contained in the pyridine ring as ammonium. The organism could not grow on mono- or disubstituted pyridinecarboxylic acids or hydroxy-, chloro-, amino-, or m...

A field study was conducted in 1982 to measure the effect of no-till (NT) and conventional till (CT) systems on N transformation after surface and subsurface applications of N fertilizers. Urea, urea-ammonium nitrate (UAN) solution, (NH4)2SO4 (AS), and CA(NO3)2 were applied to NT and CT plots (5.95 m2) at a rate of 448 kg N ha–1. A comparison of fe...

Decomposition of ¹⁴C-labeled benzidine, α-naphthylamine, and p-toluidine in soil was studied in laboratory experiments by monitoring CO2 production during a 308- to 365-d incubation period. The importance of microbial activity in decomposition of all three aromatic amines was shown by decreased ¹⁴CO² evolution in ⁶⁰Co treated soils. After 365 d of...

Laboratory experiments were conducted to quantify soil and crop interactions in a land treatment system receiving a glucose-imposed oxygen demand. Synthetic wastewaters were prepared by dissolving sufficient glucose in a plant nutrient solution to provide four levels of chemical oxygen demand (COD). The solutions were applied to soil columns croppe...

The nature of organic P in soil organic matter was studied by evaluating the incorporation of serine, phosphoserine, ethanolamine, phosphoethanolamine and glycerophosphate into model humic polymers prepared by chemical oxidation of polyphenols. Elemental and functional group analysis indicated that the composition of model humic polymers ranged as...

The stability of the phosphate ester linkage in phosphoserine (PS) and phosphoethanolamine (PE) was evaluated after incorporation of these compounds into model humic polymers. Humic polymers prepared by oxidation of a mixture of substituted phenols in the presence of either PS or PE resulted in model humic materials containing from 0.25 to 0.94% P,...

The binding of benzidine (4,4′-diaminobiphenyl), α-naphthylamine (1-aminonaphthalene) and p-toluidine (4-methylaniline) by three soils was studied by incubating soils amended with the aromatic amines and then sequentially extracting them with 60:40 (v/v) ethylacetate: methanol (EtAc: MeOH), ammonium acetate (NH4OAc) and sodium hydroxide (NaOH) as a...

The fate of pyridine and 25 substituted pyridines in soil (Aeric Ochraqualfs) was examined by measuring the quantity remaining and the inorganic N released as a result of degradation of the pyridine ring for a period of 64 d. Each compound was added to soil at 2 mmol kg⁻¹. Compounds studied included pyridine substituted with one or two hydroxyl, ca...

The fate of pyridine and 25 substituted pyridines in soil (Aeric Ochraqualfs) was examined by measuring the quantity remaining and the inorganic N released as a result of degradation of the pyridine ring for a period of 64 d. Each compound was added to soil at 2 mmol kg . Compounds studied included pyridine substituted with one or two hydroxyl, car...

The availability of sediment inorganic phosphorus (P(i)) to algae was determined in 28 suspended stream sediments collected from an agricultural watershed in northeastern Indiana by short- (2-d) and longer-term (14-d) incubations. Unincubated sediment was also analyzed for dissolved molybdate reactive P(i) (DMRP) and P(i) extracted by: (i) sequenti...

The principal inorganic pollutants of soils are particular chemical species of elements normally found at trace concentrations in soil solutions. Chemical models of the behavior of these elements have been developed to describe both the rates with which their reactions in soils occur and their resulting speciation among liquid and solid phases. The...

Land disposal of drilling fluids is a common practice following completion of an oil or gas well. A greenhouse study was conducted to determine the yield and trace element content of Swiss chard (Beta vulgaris L.) and ryegrass (Lolium perenne L.) grown in two soils containing 0, 200, or 500 g kg⁻¹ of three water-based drilling fluids. The drilli...

A standard P adsorption procedure was proposed and the ability of four laboratories to produce consistent results over a wide range of soils was determined. For this procedure, 0.5 to 1.0 g of soil were shaken in 0.01 mol L-1 CaCl2 at a soil/solution ratio of 1:25 in containers allowing a 50% head space for 24 h at 24 to 26°C on an end-over-end sha...

A study was conducted to determine the concentrations of algal-available P (Paa) in unfractionated samples and size-classified separates of soil eroded from wheat stubble plots during a simulated rainfall experiment conducted in Warren County, Indiana, U.S.A. Run-off samples were collected, concentrated, dispersed by sonification, separated accordi...

The availability of sediment P to algae was evaluated in several water stable aggregate-size fractions of suspended stream sediments collected from an agricultural watershed in northeastern Indiana. Sediments were collected during a storm event, separated into the <2, 2 to 20, 20 to 53, 53 to 212, and > 212 μm size fractions, sterilized by γ irradi...

Factors affecting the decomposition of carboxyl‐labelled (C) phthalic acid (PA), monobutyl phthalate (MBP), and dibutyl phthalate (DBP) were studied in soil incubation experiments conducted under labortory conditions. A lag phase of 10 to 20 days occurred before soil microbes initiated metabolism of MBP and DBP while PA was rapidly decomposed. Appr...

This study determined yield, metal content, and milling and baking properties of soft red winter wheat grown on soil treated with three municipal sewage sludges. Sewage sludge application ranged from 56 to 448 tonnes/ha, levels in excess of those allowed by current federal regulations; the data, therefore, represent a worst-case situation. Sludge a...

The objective of this research was to determine the effects of sewage sludge on speciation of metals in the soil solution. Sewage sludge was applied to an acid soil (pH approx. = 5) as a single treatment in 1971, or as annual treatments from 1971 through 1974 in amounts totalling from 50 to 800 t/ha. Surface soil samples were obtained from the plot...

Organic components in sewage sludges were extracted with nonaqueous solvents (hexane and methanol) and characterized by chromatography, infrared spectroscopy, and mass spectrometry. On the average, nonaqueous solvent soluble compounds represented 10.6% of sludge dry weight (24.8% of ash-free dry weight) and contained 36% of the total organic C in s...

Mineralization of organic N is one of the principle factors governing the annual amount of sewage sludge applied to agricultural cropland. The mineralization of sludge organic N was studied in a Fincastle silt loam soil treated with 24 sewage sludges obtained from sewage treatment plants in several regions of the United States. The mineralization o...

Electron spin resonance (ESR) spectroscopy was used to study the binding of Cu ²⁺ by humic acid (HA) extracted from sewage sludge. Electron spin resonance spectral data of the Cu‐HA complex and some adducts with nitrogen donors (pyridine, 1,10‐phenanthroline, ethylenediamine) showed that Cu ²⁺ formed two equatorial bonds with HA oxygen donor ligand...

Corn grain grown on soil treated with sewage sludge at different application rates was dry-milled and the resulting fractions were analyzed for protein, ash, fat, Cd, Zn, Ni, Cu, Fe and Mn. The metal concentrations in whole kernel were not significantly increased by applying from 56 to 448 metric tons of sewage sludge per hectare. Except for one Cd...

Infrared (IR) spectroscopy, between 2,000 and 1,000 cm ⁻¹ , was used to identify the mode by which carboxylates of a soil humic acid (HA) complexed Cu ²⁺ and Fe ³⁺ . Carboxylic acid groups of HA (R‐COOH) were converted to carboxylates (R‐COO ‐ ) by forming coordinate bonds with Cu ²⁺ and Fe ³⁺ . The separation Δ of the antisymmetrical and symmetric...

Electron spin resonance (ESR) spectroscopy was used to study the mechanism of Cu ²⁺ binding by humic acid (HA) extracted from a Chalmers silt loam soil. The Cu‐HA complex and some adducts with nitrogen donors were examined. The ESR data presented showed that the addition of pyridine (py) and 1,10‐phenanthroline (phen) to the Cu‐HA complex resulted...

The objectives of this study were to determine the effects of soil pH, soil moisture tension, sludge application rate, incubation temperature, and nitrification inhibitor on N transformations in soils amended with an ¹⁵ N‐labeled sewage sludge. Less than 0.1% of added sludge‐N was lost from any of the samples due to NH 3 volatilization. Nitrificati...

Oats (Avena sativa L. cv. Noble) were grown on soils treated with air-dried sewage sludge from three Indiana cities. Sludges were applied to a Chalmers silty clay loam soil at rates ranging from 56 to 448 t/ha. Oat samples were separated into groats and hulls, and concentrations of Cd, Zn, Cu, Ni, Fe, and Mn were determined in each fraction by atom...

Humic acids (HA) extracted from sludge, soil, and sludge-amended soil were characterized by elemental and functional group analyses and visible and infrared spectroscopy. Humic acid extracted from a Chalmers soil appeared to be similar to an average HA (Schnitzer, 1978). Humic acid extracted from Chicago sludge, as compared to the average HA and Ch...

The water quality problems resulting from sediment P additions to rivers and lakes can only be assessed if the biological availability of sediment‐borne P is known. A study was conducted to evaluate the availability to algae of sediment P in drainage water samples collected from an agricultural watershed in northeastern Indiana. Sediments suspended...

Progress of the Dumas and Kjeldahl procedures over the past century is reviewed. Many recent papers claim that various modifications of the standard Kjeldahl method enhance accuracy, precision, or speed, and reduce cost of analysis. Furthermore, several authors advocate use of Pyrex tubes heated in an aluminum block for digestion instead of traditi...

Infrared studies were conducted to qualitatively characterize sewage sludge light (organic) and heavy (inorganic) fractions obtained using a heavy liquid separation technique. Infrared spectra of sludge organic fractions revealed the presence of proteinaceous and polysaccharide‐like materials. Infrared absorptions characteristic of carboxyl groups...

Microbial oxidation of organic components in anaerobically digested sludge is an important aspect of the fate of sludges in soils. The objectives of this study were to determine the effects of soil characteristics, sludge management procedures, and environmental conditions on the decomposition rate of sewage sludge in soils. Synthetic sewage sludge...

Intact soil cores were used to evaluate decomposition, NH3 volatilization, N transformations, and metal movement in soils treated with sewage sludges and antibiotic processing wastes. Soil cores were leached monthly with water and incubated for 1 year. An insignificant amount (<1%) of the NH4+-N applied was lost through NH3 volatilization. The addi...

A cooperative study was conducted with Pennsylvania State University to assess the effects of wastewater irrigation on the status of soil phosphorus. The major objectives of the research were to evaluate the influence of wastewater irrigation on changes in soil organic carbon, nitrogen, and phosphorus and the sorption of orthophosphate (P). Soil sa...

The objectives of this study were to determine the extent and kinetics of sludge decomposition in soil, to evaluate the effects of sludge addition on microbial degradation of soil organic matter, and to determine the distribution of residual sludge organic C in soil organic matter fractions. Synthetic sewage sludge was prepared by anaerobically dig...

Metal‐chelate stability diagrams were developed as a function of pH and redox to predict the behavior of DTPA, EDTA, CDTA, EGTA, and HEDTA in soils. The metals evaluated include H ⁺ , Fe ³⁺ , Fe ²⁺ , Al ³⁺ , Mn ²⁺ , Ca ²⁺ , Mg ²⁺ , Zn ³⁺ , Cu ²⁺ , Cd ²⁺ , Pb ²⁺ , and Ni ²⁺ . In acid systems, Ni ²⁺ at 10 ⁻⁵ to 10 ⁻⁷ M was the predominant ligand spec...

Laboratory studies were conducted on NH3 volatilization from soils receiving synthetic wastewater sludges. Up to 25% of added inorganic N was lost as volatile NH3 from surface-applied sludge during 49 days of incubation. Volatilization of NH3 was 61% greater from soils of pH 7.5 than from soils of pH 6.0 or 5.3. Ammonia volatilization was enhanced...

Field trials on two nitrification inhibitors (nitrapyrin and terrazole) were conducted in Indiana on corn and wheat. Corn yields increased from 12 to 25% as a result of treating fall-applied anhydrous ammonia with nitrapyrin. Application of nitrification inhibitors with spring-applied N gave modest increases in corn yield. Average wheat yield incre...

Wastewater sludge samples were obtained from waste treatment streams in two wastewater treatments before and after wet-air oxidation. Wet-air oxidation resulted in a 10 to 20 percent reduction in volatile solids. Concurrently, total N levels in the sludges decreased by greater than 50 percent while P, Cu, Zn, Ni Cd, and Pb concentrations either inc...

Field trials were conducted to evaluate the effectiveness of two nitrification inhibitors (nitrapyren and terrazole) in improving the efficiency of N fertilizer utilization by corn and wheat. There were significantly increased grain protein content and protein yield of corn and wheat. Increased efficiency in crop growth resulting from inhibiting ni...

Electron Spectroscopy for Chemical Analysis (ESCA) was used to provide information concerning the chemical bonding of zinc and copper present in the sludge obtained from the Dayton, Ohio sewage treatment plant. The binding energy of the Zn 2Pââ electron in sludge when placed under a vacuum of 10⁻⁷ Torr was 1023.8 +- 0.2 eV and the binding energ...

Crystalline minerals in anaerobically digested sewage sludges were determined by x‐ray diffraction analysis. Sludge samples were prepared for x‐ray analysis by either washing with H2O to remove soluble salts or oxidizing organic matter with H2O. A limited number of minerals are present as crystalline materials in sludge. Even though the sludges con...

Soils amended with sewage sludge were incubated in the laboratory and analyzed periodically by a sequential fractionation procedure for the amounts of Cu, Zn, Cd, and Pb that were HâO-soluble, KNOâ-exchangeable, and DTPA- and HNOâ-extractable. The HâO-soluble and exchangeable metals comprised a small percentage of the total metal concentration in t...

Most studies concerning the composition of sewage sludge have placed emphasis on total elemental analysis, including sulfur. This study was conducted to determine the forms of S and their relationships to other components in sludge. Analyses of the forms and amounts of S in sewage sludge produced by 11 Indiana cities showed that total S concentrati...

A simple and rapid procedure for the determination of inorganic phosphorus in acid ammonium oxalate extracts of soils was developed by modifying the ascorbic acid‐molybdenum blue colorimetric method. The oxalate interference in the determination of P was overcome by addition of excess ammonium molybdate. A molar ratio of molybdate to oxalate, in th...

A study was conducted to develop a procedure for determining the forms and amounts of Pb, Zn, Cu, and Ni in anaerobically digested wastewater sludges obtained from 12 municipal treatment plants. Preliminary investigations were conducted to evaluate a variety of metal extractants for their complete but selective removal of specific metal forms from...