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• 1. [Article] A study of simulated water table fluctuations in a tile drained Amity soil

  A lack of reliable criteria for designing tile drainage systems in the Willamette Valley has lead to tile drainage installations in a given soil series being based on general observations of previous drain ...

  Citation × Citation Citation Abstract Copy Title: A study of simulated water table fluctuations in a tile drained Amity soil Author: Taylor, Paul Arthur A lack of reliable criteria for designing tile drainage systems in the Willamette Valley has lead to tile drainage installations in a given soil series being based on general observations of previous drain performance in the series. Relatively few quantitative measurements, which would aid in designing economical installations, have been made on existing tile systems in the Valley. An experimental tile installation with tile spacings of 30, 60, and 90 feet was made in what was considered to be a modal soil of the Amity Soil Series. Records of rainfall, tile flow, water table position, and water table profiles were obtained during the winter and spring for three years. Mathematical models programmed for a digital computer were constructed from the field data to simulate water table movement for combinations of 90, 120, and 150 foot tile spacings; unrestricted, 1.0, and 0. 5 inch per day main line capacities; surface storage; and a grassed or bare soil surface. Rainfall in the Willamette Valley is quite variable in amount and distribution from year to year, hence 16 years of hourly rainfall and monthly evaporation were used with the simulator programs to generate 16 years of monthly summaries of water table depths for March, April, and May. The data from the simulator programs were then analyzed to obtain estimates of probable water table depths for the several drainage installations simulated. Estimates were also obtained for the effects of surface cover, surface storage, restricting main line capacity, and changing tile spacing. Title: A study of simulated water table fluctuations in a tile drained Amity soil Author: Taylor, Paul Arthur A lack of reliable criteria for designing tile drainage systems in the Willamette Valley has lead to tile drainage installations in a given soil series being based on general observations of previous drain performance in the series. Relatively few quantitative measurements, which would aid in designing economical installations, have been made on existing tile systems in the Valley. An experimental tile installation with tile spacings of 30, 60, and 90 feet was made in what was considered to be a modal soil of the Amity Soil Series. Records of rainfall, tile flow, water table position, and water table profiles were obtained during the winter and spring for three years. Mathematical models programmed for a digital computer were constructed from the field data to simulate water table movement for combinations of 90, 120, and 150 foot tile spacings; unrestricted, 1.0, and 0. 5 inch per day main line capacities; surface storage; and a grassed or bare soil surface. Rainfall in the Willamette Valley is quite variable in amount and distribution from year to year, hence 16 years of hourly rainfall and monthly evaporation were used with the simulator programs to generate 16 years of monthly summaries of water table depths for March, April, and May. The data from the simulator programs were then analyzed to obtain estimates of probable water table depths for the several drainage installations simulated. Estimates were also obtained for the effects of surface cover, surface storage, restricting main line capacity, and changing tile spacing. Close

• 2. [Article] Infiltration, soil erosion, nitrogen loss and soil profile characteristics of Oregon lands occupied by three subspecies of Artemisia tridentata

  Infiltration, soil erosion, nitrogen loss and soil profile characteristics were measured on 36 sites representing land occupied by Artemisia tridentata ssp. tridentate, wyomingensis, and vaseyana. Infiltration, ...

  Citation × Citation Citation Abstract Copy Title: Infiltration, soil erosion, nitrogen loss and soil profile characteristics of Oregon lands occupied by three subspecies of Artemisia tridentata Author: Swanson, Sherman R. Infiltration, soil erosion, nitrogen loss and soil profile characteristics were measured on 36 sites representing land occupied by Artemisia tridentata ssp. tridentate, wyomingensis, and vaseyana. Infiltration, soil erosion, and nitrogen loss were strongly correlated but highly variable. Soil loss, but not infiltration or nitrogen loss was significantly different between subspecies. At Frenchglen infiltration rates were higher and soil erosion and nitrogen loss rates were lower for A.t. ssp. vaseyana sites than for A.t. ssp. wyomingensis sites. Infiltration rate decreased between plots as mean soil particle size decreased, organic ground cover decreased, bulk density increased, and extractable sodium increased. Infiltration rate was especially low on sites with vesicular porosity in the surface soil. Soil loss, and for the most part, percent nitrogen in the runoff water increased between plots as bare ground increased, and vesicular porosity in the surface soil increased, but soil and nitrogen loss was negatively correlated with medium and coarse sand and coarse fragments in the surface soil, and with organic ground cover. Aridisols lost more soil than Mollisols, but only if sites dominated by surficial tephra were omitted from the analysis, did Aridisols show significantly lower infiltration rates. The nitrogen lost in the simulation does not appear to be large in comparison with either capital or yearly flux. Nearly all characteristics of the soil profile show either no significant differences between subspecies or they show a significant interaction between location and subspecies. The Frenchglen location had the greatest elevational differences between subspecies and most of the significant physical and chemical differences between subspecies, including greater depth of maximum illuviation, greater rooting depth, and in the surface soil, lower ph, higher organic matter, higher cation exchange capacity, lower base saturation and lower percent exchangeable sodium on higher elevation A.t. ssp. vaseyana sites than on A.t. ssp. wuomingensis sites and/or A.t. ssp. tridentata sites. In the deeper soil horizons at Frenchglen, A.t. ssp. vaseyana sites had lower ph and lower base saturation than A.t. ssp. tridentata sites. Title: Infiltration, soil erosion, nitrogen loss and soil profile characteristics of Oregon lands occupied by three subspecies of Artemisia tridentata Author: Swanson, Sherman R. Infiltration, soil erosion, nitrogen loss and soil profile characteristics were measured on 36 sites representing land occupied by Artemisia tridentata ssp. tridentate, wyomingensis, and vaseyana. Infiltration, soil erosion, and nitrogen loss were strongly correlated but highly variable. Soil loss, but not infiltration or nitrogen loss was significantly different between subspecies. At Frenchglen infiltration rates were higher and soil erosion and nitrogen loss rates were lower for A.t. ssp. vaseyana sites than for A.t. ssp. wyomingensis sites. Infiltration rate decreased between plots as mean soil particle size decreased, organic ground cover decreased, bulk density increased, and extractable sodium increased. Infiltration rate was especially low on sites with vesicular porosity in the surface soil. Soil loss, and for the most part, percent nitrogen in the runoff water increased between plots as bare ground increased, and vesicular porosity in the surface soil increased, but soil and nitrogen loss was negatively correlated with medium and coarse sand and coarse fragments in the surface soil, and with organic ground cover. Aridisols lost more soil than Mollisols, but only if sites dominated by surficial tephra were omitted from the analysis, did Aridisols show significantly lower infiltration rates. The nitrogen lost in the simulation does not appear to be large in comparison with either capital or yearly flux. Nearly all characteristics of the soil profile show either no significant differences between subspecies or they show a significant interaction between location and subspecies. The Frenchglen location had the greatest elevational differences between subspecies and most of the significant physical and chemical differences between subspecies, including greater depth of maximum illuviation, greater rooting depth, and in the surface soil, lower ph, higher organic matter, higher cation exchange capacity, lower base saturation and lower percent exchangeable sodium on higher elevation A.t. ssp. vaseyana sites than on A.t. ssp. wuomingensis sites and/or A.t. ssp. tridentata sites. In the deeper soil horizons at Frenchglen, A.t. ssp. vaseyana sites had lower ph and lower base saturation than A.t. ssp. tridentata sites. Close

• 3. [Article] Soil moisture and temperature relationships under fallow in eastern Oregon

  Time of stand establishment is a critical factor affecting yields of winter wheat and barley in the fallow-crop rotation areas of the Pacific Northwest. Farmers in this winter-rainfall region are dependent ...

  Citation × Citation Citation Abstract Copy Title: Soil moisture and temperature relationships under fallow in eastern Oregon Author: Russelle, Michael P. Time of stand establishment is a critical factor affecting yields of winter wheat and barley in the fallow-crop rotation areas of the Pacific Northwest. Farmers in this winter-rainfall region are dependent on residual moisture in the seed zone for germination, because significant precipitation does not usually occur until after the optimum planting dates. Moisture is maintained near the soil surface through the summer of the fallow period by the use of a soil or stubble mulch. The rate of moisture loss is relatively low during the summer, but seems to accelerate in late August and September. This loss dries the seed zone and forces either deeper planting to reach adequate moisture or delayed seeding until precipitation re-wets the seed zone. Both practices can result in late, less vigorous stands which have lower yield potential and provide less protection from erosion. The objectives of this study were to: 1) quantify changes in seed zone water content prior to seeding; 2) determine the cause of the accelerated loss; 3) substantiate the effect of planting date on the yield of one variety of winter wheat and one variety of winter barley; 4) investigate the effect of soil temperature on the rate of first and 70% emergence of these species in the field; and 5) develop a means of predicting the average last date of planting after which stand establishment is excessively delayed at one location in eastern Oregon. Although both years were abnormally wet in late summer and fall, significant losses of seed zone water content occurred in 1976. At 6 cm, the loss period occurred in early September; at 9, 12, 15, and 18 cm, the losses occurred in late September. The measured losses were not as great as expected. No significant losses were observed in 1977 because of frequent precipitation. My hypothesis was that increasing nighttime vapor pressure gradients from the moist seed zone to the soil surface develop because of the combination of warm days and cool, clear nights characteristic of late August and September in this area. Larger vapor pressure gradients would cause increased water losses from the profile. However, no correlation was found with calculated vapor pressure gradients, the occurrence of low surface temperatures at night, or average temperature gradients in the upper soil profile. Computer simulation of isothermal liquid flow was used to discern the relative contributions of evaporative losses and of long-term redistribution of water In response to gravitational and potential gradients in the profile. Redistribution accounted for 60% of the water loss in the soil beneath the seed zone from mid-July to early August, and accounted for none of the loss from early August to early September. Planting date had a significant effect on yield of both wheat and barley; the optimum planting dates were late September to early October. On each planting date, the seeds were placed in moist soil and covered with approximately 5 cm of soil with a deep furrow drill, so temperature was the primary factor affecting rate of first and 70% emergence. Regression equations of rate of emergence on average 10-cm soil temperature from planting to emergence were highly significant. The degree days needed for first and 70% emergence for wheat were 149 and 210 using a base temperature of 0.7 and 0.4 C, respectively, and for barley were 92 and 159 using base temperatures of 6.1 and 3.5 C, respectively. Soil temperatures from 1963 to 1977 were used to develop a means of predicting average daily 10-cm soil temperature. Using this long-term average and the regression equations of rate of emergence and stand establishment versus temperature, the average last date to plant and still obtain 70% stand in 14 days was 25 September. If seeding is delayed until 15 October, lower soil temperatures will cause the average days to 70% stand of wheat to approach 22-24 days, while barley will require 24 - 2 9 days to reach 70% stand at these temperatures. Title: Soil moisture and temperature relationships under fallow in eastern Oregon Author: Russelle, Michael P. Time of stand establishment is a critical factor affecting yields of winter wheat and barley in the fallow-crop rotation areas of the Pacific Northwest. Farmers in this winter-rainfall region are dependent on residual moisture in the seed zone for germination, because significant precipitation does not usually occur until after the optimum planting dates. Moisture is maintained near the soil surface through the summer of the fallow period by the use of a soil or stubble mulch. The rate of moisture loss is relatively low during the summer, but seems to accelerate in late August and September. This loss dries the seed zone and forces either deeper planting to reach adequate moisture or delayed seeding until precipitation re-wets the seed zone. Both practices can result in late, less vigorous stands which have lower yield potential and provide less protection from erosion. The objectives of this study were to: 1) quantify changes in seed zone water content prior to seeding; 2) determine the cause of the accelerated loss; 3) substantiate the effect of planting date on the yield of one variety of winter wheat and one variety of winter barley; 4) investigate the effect of soil temperature on the rate of first and 70% emergence of these species in the field; and 5) develop a means of predicting the average last date of planting after which stand establishment is excessively delayed at one location in eastern Oregon. Although both years were abnormally wet in late summer and fall, significant losses of seed zone water content occurred in 1976. At 6 cm, the loss period occurred in early September; at 9, 12, 15, and 18 cm, the losses occurred in late September. The measured losses were not as great as expected. No significant losses were observed in 1977 because of frequent precipitation. My hypothesis was that increasing nighttime vapor pressure gradients from the moist seed zone to the soil surface develop because of the combination of warm days and cool, clear nights characteristic of late August and September in this area. Larger vapor pressure gradients would cause increased water losses from the profile. However, no correlation was found with calculated vapor pressure gradients, the occurrence of low surface temperatures at night, or average temperature gradients in the upper soil profile. Computer simulation of isothermal liquid flow was used to discern the relative contributions of evaporative losses and of long-term redistribution of water In response to gravitational and potential gradients in the profile. Redistribution accounted for 60% of the water loss in the soil beneath the seed zone from mid-July to early August, and accounted for none of the loss from early August to early September. Planting date had a significant effect on yield of both wheat and barley; the optimum planting dates were late September to early October. On each planting date, the seeds were placed in moist soil and covered with approximately 5 cm of soil with a deep furrow drill, so temperature was the primary factor affecting rate of first and 70% emergence. Regression equations of rate of emergence on average 10-cm soil temperature from planting to emergence were highly significant. The degree days needed for first and 70% emergence for wheat were 149 and 210 using a base temperature of 0.7 and 0.4 C, respectively, and for barley were 92 and 159 using base temperatures of 6.1 and 3.5 C, respectively. Soil temperatures from 1963 to 1977 were used to develop a means of predicting average daily 10-cm soil temperature. Using this long-term average and the regression equations of rate of emergence and stand establishment versus temperature, the average last date to plant and still obtain 70% stand in 14 days was 25 September. If seeding is delayed until 15 October, lower soil temperatures will cause the average days to 70% stand of wheat to approach 22-24 days, while barley will require 24 - 2 9 days to reach 70% stand at these temperatures. Close

• 4. [Article] The effects of gypsum on infiltration and surface properties of some western Oregon soils

  The effects of broadcast gypsum on infiltration rates, crusting, aggregate stability, and runoff and sediment yields were analyzed during the winter months on three West Oregon soils. The results were used ...

  Citation × Citation Citation Abstract Copy Title: The effects of gypsum on infiltration and surface properties of some western Oregon soils Author: Pronold, Michael Joseph The effects of broadcast gypsum on infiltration rates, crusting, aggregate stability, and runoff and sediment yields were analyzed during the winter months on three West Oregon soils. The results were used to evaluate its utility as a management tool to help control erosion. An application rate of two metric tons per hectare was used in the first season of testing. No differences were found between treated and untreated soil for infiltration rates, crust thickness and porosity, and aggregate stability. Runoff and sediment yields were too variable to discern differences between treated and untreated soil. The range of application rates were increased to 4, 8, and 16 metric tons of gypsum per hectare in the second season of testing. These evaluations were made at one site. The highest rate was used for comparative purposes with the untreated soil. Infiltration rates were consistently lower while sediment yields and concentrations were higher from the treated soil throughout the season. Water stable aggregate size distribution was lower in the treated soil. It was postulated that crust strength was reduced by the gypsum application. The soil surface aggregates from the treated soil were consistently higher in moisture content. This decreased the infiltration rates and provided a more erodible condition. Runoff and sediment yields from the erosion plots were more dependent on vegetative cover than on treatment. Title: The effects of gypsum on infiltration and surface properties of some western Oregon soils Author: Pronold, Michael Joseph The effects of broadcast gypsum on infiltration rates, crusting, aggregate stability, and runoff and sediment yields were analyzed during the winter months on three West Oregon soils. The results were used to evaluate its utility as a management tool to help control erosion. An application rate of two metric tons per hectare was used in the first season of testing. No differences were found between treated and untreated soil for infiltration rates, crust thickness and porosity, and aggregate stability. Runoff and sediment yields were too variable to discern differences between treated and untreated soil. The range of application rates were increased to 4, 8, and 16 metric tons of gypsum per hectare in the second season of testing. These evaluations were made at one site. The highest rate was used for comparative purposes with the untreated soil. Infiltration rates were consistently lower while sediment yields and concentrations were higher from the treated soil throughout the season. Water stable aggregate size distribution was lower in the treated soil. It was postulated that crust strength was reduced by the gypsum application. The soil surface aggregates from the treated soil were consistently higher in moisture content. This decreased the infiltration rates and provided a more erodible condition. Runoff and sediment yields from the erosion plots were more dependent on vegetative cover than on treatment. Close

• 5. [Article] Soils of the Oregon coastal fog belt in relation to the proposed "Andisol" order

  A study was conducted to evaluate the properties of soils in the fog belt area of the Oregon Coast Range. Soils in the study were chosen to include only those belonging to Andepts or to andic subgroups. ...

  Citation × Citation Citation Abstract Copy Title: Soils of the Oregon coastal fog belt in relation to the proposed "Andisol" order Author: Badayos, Rodrigo Briones A study was conducted to evaluate the properties of soils in the fog belt area of the Oregon Coast Range. Soils in the study were chosen to include only those belonging to Andepts or to andic subgroups. Samples were collected from eleven sites that were formed mostly from colluvial deposits of basaltic rocks, sedimentary rocks, and alluvium derived from volcanic and sedimentary rocks. The soils studied were characterized chemically and physically, and the mineralogy of the very fine sand and clay size fractions was determined. The eleven soils were classified on the assumption that Andisol is added in the Soil Taxonomy as the 11th order. Based on the low degree of profile differentiation shown by profile morphology, it was concluded that all of the soils studied are in an early stage of development. The soil structure is mostly granular in the surface and fine subangular blocky in the subsoil. Field texture and laboratory analyses indicate low percentage clay compared to silt throughout the profiles. Surface layers are mostly dark colored. All the soils have low bulk density, high water holding capacity at high suction (15 bar), high CEC, high organic carbon, high pH in NaF, high variable charge, and high phosphorus retention -all of which indicate a high proportion of amorphous materials in the clay fraction. Based on the mineralogy of the very fine sand fraction and field site observations, it was concluded that basaltic and volcaniclastic rocks were the major sources of the parent materials that have weathered to produce a dominance of amorphous materials in the soils studied. Chloritic intergrade dominates the crystalline clay size components of all the soils with minor amounts of smectite, mica, gibbsite, chlorite, halloysite, and kaolinite. It was concluded that three out of the eleven soils studied, have chemical characteristics of spodic horizons based on the amount of extractable Fe and Al measured, These soils were classified as Troporthods. Eight of the eleven soils were provisionally classified as Andisols. Seven of the eight Andisols were placed in the subgroup Typic Haplotropands and one under the subgroup Typic Haploborand. Title: Soils of the Oregon coastal fog belt in relation to the proposed "Andisol" order Author: Badayos, Rodrigo Briones A study was conducted to evaluate the properties of soils in the fog belt area of the Oregon Coast Range. Soils in the study were chosen to include only those belonging to Andepts or to andic subgroups. Samples were collected from eleven sites that were formed mostly from colluvial deposits of basaltic rocks, sedimentary rocks, and alluvium derived from volcanic and sedimentary rocks. The soils studied were characterized chemically and physically, and the mineralogy of the very fine sand and clay size fractions was determined. The eleven soils were classified on the assumption that Andisol is added in the Soil Taxonomy as the 11th order. Based on the low degree of profile differentiation shown by profile morphology, it was concluded that all of the soils studied are in an early stage of development. The soil structure is mostly granular in the surface and fine subangular blocky in the subsoil. Field texture and laboratory analyses indicate low percentage clay compared to silt throughout the profiles. Surface layers are mostly dark colored. All the soils have low bulk density, high water holding capacity at high suction (15 bar), high CEC, high organic carbon, high pH in NaF, high variable charge, and high phosphorus retention -all of which indicate a high proportion of amorphous materials in the clay fraction. Based on the mineralogy of the very fine sand fraction and field site observations, it was concluded that basaltic and volcaniclastic rocks were the major sources of the parent materials that have weathered to produce a dominance of amorphous materials in the soils studied. Chloritic intergrade dominates the crystalline clay size components of all the soils with minor amounts of smectite, mica, gibbsite, chlorite, halloysite, and kaolinite. It was concluded that three out of the eleven soils studied, have chemical characteristics of spodic horizons based on the amount of extractable Fe and Al measured, These soils were classified as Troporthods. Eight of the eleven soils were provisionally classified as Andisols. Seven of the eight Andisols were placed in the subgroup Typic Haplotropands and one under the subgroup Typic Haploborand. Close

• 6. [Article] Nature of interlayer material in silicate clays of selected Oregon soils

  A study was conducted to investigate the nature of hydroxy interlayers in the chlorite-like intergrade clays of three Oregon soils with respect to kind, amount, stability, and conditions of formation. The ...

  Citation × Citation Citation Abstract Copy Title: Nature of interlayer material in silicate clays of selected Oregon soils Author: Singleton, P. C. A study was conducted to investigate the nature of hydroxy interlayers in the chlorite-like intergrade clays of three Oregon soils with respect to kind, amount, stability, and conditions of formation. The clays of the Hembre, Wren, and Lookout soils, selected to represent weathering products originating from basaltic materials under humid, subhumid, and semi-arid climatic conditions respectively, were subjected to a series of progressive treatments designed to effect a differential dissolution of the materials intimately associated with them. The treatments, chosen to represent a range of increasing severity of dissolution, were (1) distilled water plus mechanical stirring, (2) boiling 2% sodium carbonate, (3) buffered sodium citrate-dithionite, (4) boiling sodium hydroxide, and (5) preheating to 400 °C for 4 hours plus boiling sodium hydroxide. Extracts from the various steps of the dissolution procedure were chemically analyzed in order to identify the materials removed from the clays. X-ray diffraction analysis and cation exchange capacity determinations were made on the clays after each step, and any differences noted in the measured values were attributed to the removal of hydroxy interlayers from the clays. Hydroxy interlayers were found to occur more in the Hembre and Wren soils than in the Lookout soil, with the most stable interlayers occurring in the Wren. Soil reaction was one of the major differences between these soils. The pH values of the Hembre and Wren ranged between 4.5 and 5.0, while that of the Lookout soil was near neutral at the surface and 8.3 in the zone of calcium carbonate accumulation. It appeared from the data, that the parent material of the Wren soil had reached a more advanced stage of weathering than that of the other soils. The data from the Hembre clays showed that hydroxy interlayers formed to the greatest extent in the surface horizon and decreased with depth. Such interlayers occurred in the A and B horizons of the Wren clays in about equal amounts, but less in the C horizon. The zone of clay enrichment in the B horizon of the Wren soil suggests a downward movement of clay in the profile. Consequently, it is conceivable that some of the interlayer hydroxides formed in the A horizon would ultimately have reached the B horizon. There appeared to be as much interlayering in the C horizon clays of the Lookout soil as in the upper horizons. This seems to contradict the idea that interlayering develops most in the upper horizons where weathering is greatest. The apparent anomaly is resolved, however, if the lithologic discontinuity in the profile is taken into consideration. Evidence indicates that the present C horizon of the Lookout soil may have been a surface soil at one time. Chemical analysis of the treatment extracts suggests that iron and magnesium as well as aluminum probably occupy the interlayer positions of the clays studied. A part of the magnesium was presumed to have been residuum from brucite interlayers of degraded chlorite. The results indicated that intergrade clays may have formed both from chloritization, and from chlorite degradation. The high amount of chlorite in the Hembre parent materials together with the acid environmental conditions probably led to some chlorite breakdown. Somewhat similar conditions existed in the Wren soil. There is, however, a high amount of biotite in the parent materials of the Wren soil that could readily weather to an intergrade by being altered to smectite or vermiculite and undergoing subsequent chloritization. The intergrades in the Lookout soil clays apparently formed from chloritization of smectites in as much as no chlorite was observed in the parent materials. Title: Nature of interlayer material in silicate clays of selected Oregon soils Author: Singleton, P. C. A study was conducted to investigate the nature of hydroxy interlayers in the chlorite-like intergrade clays of three Oregon soils with respect to kind, amount, stability, and conditions of formation. The clays of the Hembre, Wren, and Lookout soils, selected to represent weathering products originating from basaltic materials under humid, subhumid, and semi-arid climatic conditions respectively, were subjected to a series of progressive treatments designed to effect a differential dissolution of the materials intimately associated with them. The treatments, chosen to represent a range of increasing severity of dissolution, were (1) distilled water plus mechanical stirring, (2) boiling 2% sodium carbonate, (3) buffered sodium citrate-dithionite, (4) boiling sodium hydroxide, and (5) preheating to 400 °C for 4 hours plus boiling sodium hydroxide. Extracts from the various steps of the dissolution procedure were chemically analyzed in order to identify the materials removed from the clays. X-ray diffraction analysis and cation exchange capacity determinations were made on the clays after each step, and any differences noted in the measured values were attributed to the removal of hydroxy interlayers from the clays. Hydroxy interlayers were found to occur more in the Hembre and Wren soils than in the Lookout soil, with the most stable interlayers occurring in the Wren. Soil reaction was one of the major differences between these soils. The pH values of the Hembre and Wren ranged between 4.5 and 5.0, while that of the Lookout soil was near neutral at the surface and 8.3 in the zone of calcium carbonate accumulation. It appeared from the data, that the parent material of the Wren soil had reached a more advanced stage of weathering than that of the other soils. The data from the Hembre clays showed that hydroxy interlayers formed to the greatest extent in the surface horizon and decreased with depth. Such interlayers occurred in the A and B horizons of the Wren clays in about equal amounts, but less in the C horizon. The zone of clay enrichment in the B horizon of the Wren soil suggests a downward movement of clay in the profile. Consequently, it is conceivable that some of the interlayer hydroxides formed in the A horizon would ultimately have reached the B horizon. There appeared to be as much interlayering in the C horizon clays of the Lookout soil as in the upper horizons. This seems to contradict the idea that interlayering develops most in the upper horizons where weathering is greatest. The apparent anomaly is resolved, however, if the lithologic discontinuity in the profile is taken into consideration. Evidence indicates that the present C horizon of the Lookout soil may have been a surface soil at one time. Chemical analysis of the treatment extracts suggests that iron and magnesium as well as aluminum probably occupy the interlayer positions of the clays studied. A part of the magnesium was presumed to have been residuum from brucite interlayers of degraded chlorite. The results indicated that intergrade clays may have formed both from chloritization, and from chlorite degradation. The high amount of chlorite in the Hembre parent materials together with the acid environmental conditions probably led to some chlorite breakdown. Somewhat similar conditions existed in the Wren soil. There is, however, a high amount of biotite in the parent materials of the Wren soil that could readily weather to an intergrade by being altered to smectite or vermiculite and undergoing subsequent chloritization. The intergrades in the Lookout soil clays apparently formed from chloritization of smectites in as much as no chlorite was observed in the parent materials. Close

• 7. [Article] Genesis of some soils in the central western Cascades of Oregon

  Soils representative of several landscape units in the H. J. Andrews Experimental Forest, Western Cascade Range, were sampled, analyzed, and tentatively classified. Genetic inferences were drawn relating ...

  Citation × Citation Citation Abstract Copy Title: Genesis of some soils in the central western Cascades of Oregon Author: Brown, R. B. Soils representative of several landscape units in the H. J. Andrews Experimental Forest, Western Cascade Range, were sampled, analyzed, and tentatively classified. Genetic inferences were drawn relating soils to landscape position and other factors of soil formation. Descriptive information and nutrient capital data were provided to support ecosystem modelling efforts by the Coniferous Forest Biome study group of the U. S./International Biological Program (IBP). To meet the "nutrient capital" requirements of IBP, and to gain insight particularly into the effects of coarse fragments on soil genesis, a volumetric approach was used. Soil organic matter, total N, extractable P, exchangeable cations, free Fe oxides, and cation exchange capacity were expressed in terms of weight or equivalents per unit volume of "whole soil," defined as organic and mineral fine earth components plus pore space plus coarse fragments. The various entities, in grams or equivalents per liter of whole soil, were observed as to their variation with depth. Additional calculations showed levels of the various entities per surface meter ³ of whole soil. Soil temperature data from several sites within the Andrews Forest showed the mesic-frigid soil temperature regime boundary to fall at about the 600 m (2, 000 ft) elevation on south slopes and at about the 450 m (1, 500 ft) elevation on north slopes. The frigidcryic boundary apparently was above the 1, 500 m (4,900 ft) elevation in the Andrews Forest. A sequence of three fluvial and two colluvial soils ranging in elevation from 440 to 460 m was studied in conjunction with concurrent IBP investigations into the geomorphic history of the area The soil on a floodplain adjacent to Lookout Creek, in the sandy-skeletal, mixed, mesic family of Fluventic Hapludolls, was between 500 and 7, 000 yrs in age. The adjacent stream terrace soil, in the loamyskeletal, mixed, mesic family of Fluventic Dystrochrepts, was > 7, 000 yrs old as evidenced Mazama pumice erposi tE-; on or near the surface of the terrace. Volumetric analysis suggested that the floodplain soil had a mollic epipedon largely by virtue of its high content of coarse fragments. The coarse fragments caused a concentration of soil organic matter and recycled cations into a smaller volume of fine earth as compared with the terrace soil, which was lower in coarse fragments. An alluvial-colluvial fan emanated from an adjacent slope and lapped onto the terrace. The soil in this fan was a member of the Fluventic Eutrochrepts, loamy-skeletal, mixed, mesic. It was high in base status and moderately high in clay content, apparently because the southeast-facing source area for parent material here had experienced only shallow weathering and minimal leaching. Across Lookout Creek from these landscape units was a remnant of a high colluvial terrace emanating from a northwest-facing watershed. At the crest of this fan remnant the soil was a member of the loamy-skeletal, mixed, mesic family of Fluventic Dystrochrepts with a distinct layer of Mazama pumice at the 75 to 85 cm depth. This terrace is cut by the watershed stream, which has deposited a comparatively well sorted fan. Soils are in the coarseloamy, mixed, mesic family of Fluventic Dystrochrepts, Eight landscape units in longitudinal and transverse crosssections of upper McRae Creek valley, ranging in elevation from 800 to 1, 200 m, were chosen to study upland soil genesis. Proceeding up the valley, stage of profile development appeared to decrease, indicating a series of depositional events. Soils varied from Eutric Glossoboralfs, fine, mixed on the lowermost surface to Fluventic Dystrochrepts, fine-loamy, mixed, frigid on the next higher surface, to Fluventic Dystrochrepts, loamy-skeletal, mixed, frigid on the next higher surface, to Typic Haplumbrepts, loamy-skeletal, mixed, frigid on the backslope at the valley headwall. The two lowermost soils contrasted markedly with the two uppermost soils, being lower in content of organic matter and N, and higher in base status and clay content. The upper two soils, typical of upper valley bottom and sideslope soils in the region, were extremely low in exchangeable bases and base saturation as measured at pH 7. Compared with the two lower soils, however, these upper soils had relatively high soil: water pH values and relatively small drops in pH from soil:water to soil :KCI measurement. This may be an indication that the upper soils were higher in amorphous content. Greater pH-dependent-CEC would have caused the upper soils to exhibit unrealistically high CEO s--and thus low base saturations--when measured at pH 7. A topoclimosequence of soils on north, east (saddle), and south-facing landscape units with a single parent rock lithology was studied in the transverse valley transect. All three soils were placed tentatively in the Andic Dystrochrepts. The north-facing soil was in a medial - skeletal, frigid family, was the deepest to bedrock ( > 1 1/2 m), aria had the freshest coarse fragments of the three soils. The saddle and south-facing soils were in medial-skeletal, frigid and medial, frigid families, respectively. They were shallow ( <1 m) to saprolite bedrock, with well weathered coarse fragments in the regolith, demonstrating shallower, but apparently more intense weathering on the more exposed sites. These more exposed soils were darker in color than the north-facing soil. Soil organic matter levels were not strikingly different among the three soils. Soil N levels were significantly higher in the south-facing soil than in the east and north-facing soils. Levels of exchangeable bases, while low, were not as low in these three soils as in the upper valley bottom and backslope soils. Saprolite horizons had higher base saturations than overlying horizons. Title: Genesis of some soils in the central western Cascades of Oregon Author: Brown, R. B. Soils representative of several landscape units in the H. J. Andrews Experimental Forest, Western Cascade Range, were sampled, analyzed, and tentatively classified. Genetic inferences were drawn relating soils to landscape position and other factors of soil formation. Descriptive information and nutrient capital data were provided to support ecosystem modelling efforts by the Coniferous Forest Biome study group of the U. S./International Biological Program (IBP). To meet the "nutrient capital" requirements of IBP, and to gain insight particularly into the effects of coarse fragments on soil genesis, a volumetric approach was used. Soil organic matter, total N, extractable P, exchangeable cations, free Fe oxides, and cation exchange capacity were expressed in terms of weight or equivalents per unit volume of "whole soil," defined as organic and mineral fine earth components plus pore space plus coarse fragments. The various entities, in grams or equivalents per liter of whole soil, were observed as to their variation with depth. Additional calculations showed levels of the various entities per surface meter ³ of whole soil. Soil temperature data from several sites within the Andrews Forest showed the mesic-frigid soil temperature regime boundary to fall at about the 600 m (2, 000 ft) elevation on south slopes and at about the 450 m (1, 500 ft) elevation on north slopes. The frigidcryic boundary apparently was above the 1, 500 m (4,900 ft) elevation in the Andrews Forest. A sequence of three fluvial and two colluvial soils ranging in elevation from 440 to 460 m was studied in conjunction with concurrent IBP investigations into the geomorphic history of the area The soil on a floodplain adjacent to Lookout Creek, in the sandy-skeletal, mixed, mesic family of Fluventic Hapludolls, was between 500 and 7, 000 yrs in age. The adjacent stream terrace soil, in the loamyskeletal, mixed, mesic family of Fluventic Dystrochrepts, was > 7, 000 yrs old as evidenced Mazama pumice erposi tE-; on or near the surface of the terrace. Volumetric analysis suggested that the floodplain soil had a mollic epipedon largely by virtue of its high content of coarse fragments. The coarse fragments caused a concentration of soil organic matter and recycled cations into a smaller volume of fine earth as compared with the terrace soil, which was lower in coarse fragments. An alluvial-colluvial fan emanated from an adjacent slope and lapped onto the terrace. The soil in this fan was a member of the Fluventic Eutrochrepts, loamy-skeletal, mixed, mesic. It was high in base status and moderately high in clay content, apparently because the southeast-facing source area for parent material here had experienced only shallow weathering and minimal leaching. Across Lookout Creek from these landscape units was a remnant of a high colluvial terrace emanating from a northwest-facing watershed. At the crest of this fan remnant the soil was a member of the loamy-skeletal, mixed, mesic family of Fluventic Dystrochrepts with a distinct layer of Mazama pumice at the 75 to 85 cm depth. This terrace is cut by the watershed stream, which has deposited a comparatively well sorted fan. Soils are in the coarseloamy, mixed, mesic family of Fluventic Dystrochrepts, Eight landscape units in longitudinal and transverse crosssections of upper McRae Creek valley, ranging in elevation from 800 to 1, 200 m, were chosen to study upland soil genesis. Proceeding up the valley, stage of profile development appeared to decrease, indicating a series of depositional events. Soils varied from Eutric Glossoboralfs, fine, mixed on the lowermost surface to Fluventic Dystrochrepts, fine-loamy, mixed, frigid on the next higher surface, to Fluventic Dystrochrepts, loamy-skeletal, mixed, frigid on the next higher surface, to Typic Haplumbrepts, loamy-skeletal, mixed, frigid on the backslope at the valley headwall. The two lowermost soils contrasted markedly with the two uppermost soils, being lower in content of organic matter and N, and higher in base status and clay content. The upper two soils, typical of upper valley bottom and sideslope soils in the region, were extremely low in exchangeable bases and base saturation as measured at pH 7. Compared with the two lower soils, however, these upper soils had relatively high soil: water pH values and relatively small drops in pH from soil:water to soil :KCI measurement. This may be an indication that the upper soils were higher in amorphous content. Greater pH-dependent-CEC would have caused the upper soils to exhibit unrealistically high CEO s--and thus low base saturations--when measured at pH 7. A topoclimosequence of soils on north, east (saddle), and south-facing landscape units with a single parent rock lithology was studied in the transverse valley transect. All three soils were placed tentatively in the Andic Dystrochrepts. The north-facing soil was in a medial - skeletal, frigid family, was the deepest to bedrock ( > 1 1/2 m), aria had the freshest coarse fragments of the three soils. The saddle and south-facing soils were in medial-skeletal, frigid and medial, frigid families, respectively. They were shallow ( <1 m) to saprolite bedrock, with well weathered coarse fragments in the regolith, demonstrating shallower, but apparently more intense weathering on the more exposed sites. These more exposed soils were darker in color than the north-facing soil. Soil organic matter levels were not strikingly different among the three soils. Soil N levels were significantly higher in the south-facing soil than in the east and north-facing soils. Levels of exchangeable bases, while low, were not as low in these three soils as in the upper valley bottom and backslope soils. Saprolite horizons had higher base saturations than overlying horizons. Close

• 8. [Article] Influence of anhydrous ammonia on the solubility of soil organic matter

  Four surface and three subsurface horizons of agriculturally important Oregon soils were exposed to excessive volumes of anhydrous ammonia and reequilibrated with the atmosphere for several time periods ...

  Citation × Citation Citation Abstract Copy Title: Influence of anhydrous ammonia on the solubility of soil organic matter Author: Mangum, Doris Louell Four surface and three subsurface horizons of agriculturally important Oregon soils were exposed to excessive volumes of anhydrous ammonia and reequilibrated with the atmosphere for several time periods prior to extraction with water. The carbon solubilized was determined by a modified wet combustion technique. Nitrogen in the soils, extracts, and residues was determined by a micro-Kjeldahl procedure. About three to ten % of the indigenous carbon was extracted. The actual amount of carbon solubilized was proportional to the original soil carbon contents, This amount of carbon approximated that solubilized during extraction of soils with 0.15 N NH₄OH. The soil moisture content at ammoniation time appeared to have little influence on the quantity of carbon solubilized. With an increase in reequilibration time with the atmosphere there was only a slight decrease in the amount of carbon extracted. Anhydrous ammonia application and subsequent aeration increased nitrogen contents over the indigenous values about twice as much in the C horizons as in the A horizons. Within three days 20 to 50% of the initially retained nitrogen was lost to the atmosphere. The pH values of the soils and extracts corresponded to the nitrogen values and decreased with the length of time elapsing prior to extraction, Assuming that the laboratory treatments and extracting methods were much more severe and effective in solubilizing organic matter than would be expected under field conditions, it is suggested that soil structural changes due to organic matter solubilization after anhydrous ammonia application would be minor. Changes in structural stability may be more related to phenomena accompanying large pH changes than to dissolution and redistribution of the organic fraction. Title: Influence of anhydrous ammonia on the solubility of soil organic matter Author: Mangum, Doris Louell Four surface and three subsurface horizons of agriculturally important Oregon soils were exposed to excessive volumes of anhydrous ammonia and reequilibrated with the atmosphere for several time periods prior to extraction with water. The carbon solubilized was determined by a modified wet combustion technique. Nitrogen in the soils, extracts, and residues was determined by a micro-Kjeldahl procedure. About three to ten % of the indigenous carbon was extracted. The actual amount of carbon solubilized was proportional to the original soil carbon contents, This amount of carbon approximated that solubilized during extraction of soils with 0.15 N NH₄OH. The soil moisture content at ammoniation time appeared to have little influence on the quantity of carbon solubilized. With an increase in reequilibration time with the atmosphere there was only a slight decrease in the amount of carbon extracted. Anhydrous ammonia application and subsequent aeration increased nitrogen contents over the indigenous values about twice as much in the C horizons as in the A horizons. Within three days 20 to 50% of the initially retained nitrogen was lost to the atmosphere. The pH values of the soils and extracts corresponded to the nitrogen values and decreased with the length of time elapsing prior to extraction, Assuming that the laboratory treatments and extracting methods were much more severe and effective in solubilizing organic matter than would be expected under field conditions, it is suggested that soil structural changes due to organic matter solubilization after anhydrous ammonia application would be minor. Changes in structural stability may be more related to phenomena accompanying large pH changes than to dissolution and redistribution of the organic fraction. Close