Soil Science Society of America Journal
1435-0661
0361-5995
Mỹ
Cơ quản chủ quản: WILEY , John Wiley & Sons Inc.
Lĩnh vực:
Soil Science
Phân tích ảnh hưởng
Thông tin về tạp chí
SSSA Journal publishes content on soil physics; hydrology; soil chemistry; soil biology; soil biochemistry; soil fertility; plant nutrition; pedology; soil and water conservation and management; forest, range, and wildland soils; soil and plant analysis; soil mineralogy, wetland soils. The audience is researchers, students, soil scientists, hydrologists, pedologist, geologists, agronomists, arborists, ecologists, engineers, certified practitioners, soil microbiologists, and environmentalists. The journal publishes original research, issue papers, reviews, notes, comments and letters to the editor, and book reviews. Invitational papers may be published in the journal if accepted by the editorial board.
Các bài báo tiêu biểu
Changes in Soil Microbial Community Structure in a Tallgrass Prairie Chronosequence Increasing the abundance of fungi relative to bacteria should favor C accrual, because fungi use C more efficiently, and are composed of more recalcitrant C compounds. We examined changes in soil microbial community structure following cessation of tillage‐based agriculture and through subsequent succession in a C‐accruing tallgrass prairie restoration chronosequence. We predicted that the relative abundance of fungi would increase following conversion from tillage‐based agriculture. Soil microbial community structure was assessed as relative abundances of phospholipid fatty acids (PLFAs). Cessation of tillage‐based agriculture did initially lead to an increase in the abundance of fungi, particularly arbuscular mycorrhizal fungi (AMF), relative to bacteria. We suggest this is primarily due to reduced disturbance when tilling ceases. Vegetation characteristics also appear to be important, with high cyclopropyl/precursor PLFA ratios indicating bacterial communities under stress in agricultural soils, probably due to low C, and possibly to low C relative to N inputs. A secondary gradient in soil microbial community structure was related to successional time, and tied to soil characteristics, particularly bulk density (Db ), pH, and soil organic C and N. However, while the fungi/bacteria (F/B) ratio was high in early succession plots, it declined later in succession. In addition, although the F/B ratio increased with SOC in the agricultural soils, it decreased with SOC in prairie soils. We conclude that increased community metabolic efficiency due to higher relative abundances of fungi is not the primary mechanism leading to enhanced C storage in these soils.
Tập 69 Số 5 - Trang 1412-1421 - 2005
Soils of Steeply Sloping Landscapes in the Southern Appalachian Mountains Abstract At two locations in the southern Appalachian Mountains, soils at two slope positions on north‐ and south‐facing landscapes were described, sampled, and analyzed to determine the relative effect of slope aspect and position upon the differentiation of the parent rock into soil profiles. At the southwestern Virginia study area, the parent rocks are highly siliceous sandstone and siltstone, whereas, the parent rock in southwestern North Carolina is a granitic biotite gneiss. Soils developed from the siliceous parent material were very similar in morphological, physical, chemical, and mineralogical properties irrespective of aspect and slope position. In contrast, there was a high degree of soil profile differentiation at the two slope positions and on the two aspects in North Carolina. In addition to differences in morphological and physical properties, there are distinct differences in the clay mineral suites on opposing aspects. Kaolin and the pedogenic 2:1–2:2 intergrade minerals are predominant in the soils of the north‐facing landscapes, whereas, gibbsite is the major clay mineral in the soils of the south‐facing landscape.
Tập 34 Số 3 - Trang 473-478 - 1970
Humic and Fulvic Acid Adsorption by Silicon and Aluminum Oxide Surfaces on Clay Minerals Abstract Natural (untreated) clays are most probably amorphous on their outermost surface layers due to the continuous and natural process of partial dissolution and reprecipitation of the clay components at the solid‐aqueous interface. The pH‐dependent adsorption on Al and Si oxides, mordenite, kaolinite, and montmorillonite of a humic acid (HA) and a fulvic acid (FA) was described as occurring on Al and Si sites. The surfaces of the clay minerals were modeled as mixtures of amorphous Al and Si oxides. The results showed a strong adsorption of the organics by the Al sites on the Al oxide and kaolinite, and a weak adsorption of organics by the Si sites on the Si oxide, mordenite, and montmorillonite. At low pH values, the Si sites on the Si oxide, mordenite, and montmorillonite adsorbed FA; these latter observations strongly suggest that the adsorption of FA by the interplanar spaces of expanding clays is driven by forces that can be studied using amorphous Si oxide as the adsorbent. Multivalent cations will form organo‐metallic complexes that significantly increase adsorption, particularly on Si sites; exceptions were found with some FA‐metal complexes, which were attributed to the degree of complexation. The implication of these observations is that, in natural systems, the adsorption of aqueous compounds is highly dependent on the type of (amorphous) surface present at the outermost layer of the solid phase in contact with the liquid phase.
Tập 55 Số 1 - Trang 34-42 - 1991
The Influence of Organic Carbon on Nitrogen Transformations in Five Wetland Soils Today we see an increased use of wetlands for N removal in agricultural catchments. Since the most important process for nitrate (NO− 3 ) removal, denitrification, requires organic C, different soils could be expected to be differently suited for wetland construction. In this study, we evaluate the importance of soil organic C and the effects of added dissolved organic C on N transformations in existing and proposed wetlands. We used 15 N‐labeled NO− 3 to study N transformations in soil columns from five locations (a forest peaty soil, a field peaty soil, a silt loam, a loam, and a sandy loam). All five soils removed NO− 3 at substantial rates (13–73% of the load). The field peaty soil had highest denitrification rate (11 mmol m−2 d−1 ), while sandy loam soil had the lowest rate (2 mmol m−2 d−1 ). Dissolved organic C did not seem to limit N removal in the soils, as glucose additions affected N turnover only slightly. The forest peat soil differed from the others by exhibiting low nitrification, and relatively high production of nitrite (NO− 2 ), probably a result of low pH. Nitrate removal in the field peat soil and the sandy loam soil was counteracted by production of ammonium (NH+ 4 ) and dissolved organic N, causing net N release. Although there was a positive relationship between soil organic matter and NO− 3 consumption, we conclude that all soils were suited for N removal. The lack of response to glucose additions indicate that there was no short‐term lack of electron donor in any of the soils, including the sandy loam soil.
Tập 64 Số 3 - Trang 1129-1136 - 2000
Nature and Rates of Selenium Transformations: A Laboratory Study of Kesterson Reservoir Soils
Tập 60 Số 3 - Trang 791-800 - 1996
Selenate and Selenite Sorption on Iron Oxides An Infrared and Electrophoretic Study We studied selenate and selenite sorption by amorphous Fe oxide [am‐Fe(OH)3 ] and goethite (α‐FeOOH) as a function of time (25 min–96 h), pH (3–12), ionic strength (0.01–1.0 M NaCl), and total Se concentration (0.0001–1.0 M ). We examined sorbed selenate and selenite by in situ attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopy, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and electrophoresis to deduce sorption mechanisms. Sorption of both selenate and selenite reached equilibrium in <25 min and the sorption isotherm was not reversible. Increasing ionic strength decreased selenate sorption but did not affect selenite sorption. The presence of either selenate or selenite lowered the electrophoretic mobility (EM) and decreased the point of zero charge (PZC) of both sorbents, suggesting inner‐sphere complexation for both selenate and selenite species. Both in situ ATR–FTIR and DRIFT difference spectra showed bidentate complexes of selenate with am‐Fe(OH)3 The structure of selenite complexes in am‐Fe(OH)3 –solution interface was uncertain due to insensitivity of the in situ ATR–FTIR technique. The DRIFT spectra of selenite on am‐Fe(OH)3 showed ν3 splitting as evidence of complexation. The DRIFT spectra of selenite on goethite showed bridging bidentate complex of selenite. We conclude that the influence of ionic strength on Se sorption cannot be used as a criterion for distinguishing outer‐ vs. inner‐sphere complex formation.
Tập 64 Số 1 - Trang 101-111 - 2000
Selenium Adsorption by Goethite Abstract The adsorption of Se by goethite was studied as a function of time (10 min–24 h), temperature (295.5 and 303.5 K), pH (4–11), particle concentration (3–300 mg/L), total Se concentration (0.02–5 × 10−5 M ), oxidation state [Se(IV) and Se(VI)], and competing anion concentration [(anion)/(Se(IV) = 0.25 to 50 000] in order to assess the influence of these factors on Se mobility. The data indicate that (i) the surface sites of goethite are heterogeneous, (ii) the adsorption of selenite [Se(IV)] reaches equilibrium in 2 h and is completely reversible with respect to pH, (iii) the removal of selenite from solution increases with decreasing pH and increasing particle concentration, (iv) the adsorption edge for selenite shifts to lower pH values with increasing total selenite concentrations, (v) selenite adsorbs much more strongly than selenate [Se(VI)], and (vi) the influence of additional anions on selenite adsorption depends on the relative affinity of the anions for the surface and the relative concentrations of the anions. For a given anion concentration ratio, the competition sequence with selenite is phosphate > silicate ≥ citrate > molybdate > bicarbonate/carbonate > oxalate > fluoride > sulfate. Therefore, the conditions that favor the mobility of Se in the environment with respect to adsorption are alkaline pH, high Se concentrations, oxidizing conditions, and high concentrations of additional anions that strongly adsorb.
Tập 51 Số 5 - Trang 1145-1151 - 1987
Temporal Stability of Spatially Measured Soil Water Probability Density Function Abstract Soil water data collected from three different fields are analyzed by two techniques (temporal analysis of the differences between individual and spatial average values; and Spearman's rank correlation) to search if time‐invariant characteristic statistical properties of the probability density functions can be assigned to individual locations. A grass field was equipped with 17 neutron access tubes and surveyed 24 times during a 2 1/2 yr‐period. In another field planted with olive trees, nine neutron access tubes were installed and quarterly measurements were performed during two consecutive years. The latter field cropped in wheat was gravimetrically sampled on a regular spatial pattern five different times and was routinely surveyed during a 1‐yr period at four selected locations by using a neutron moisture meter. All data show the existence of a very significant time‐stability of particular individual locations characterized by the same parameter in the statistical distribution of the observations taken over the field. It is shown that some locations conserve the property to represent the mean and extreme values of the field water content at any time along the year. This stability seems to be explained to a large extent by relationships between soil texture and water content.
Tập 49 Số 4 - Trang 822-828 - 1985
Using a New Criterion to Identify Sites for Mean Soil Water Storage Evaluation Establishing a few sites in which measurements of soil water storage (SWS) are time stable significantly reduces the efforts involved in determining average values of SWS. This study aimed to apply a new criterion—the mean absolute bias error (MABE)—to identify temporally stable sites for mean SWS evaluation. The performance of MABE was compared with that of the commonly used criterion, the standard deviation of relative difference (SDRD). From October 2004 to October 2008, SWS of four soil layers (0–1.0, 1.0–2.0, 2.0–3.0, and 3.0–4.0 m) was measured, using a neutron probe, at 28 sites on a hillslope of the Loess Plateau, China. A total of 37 SWS data sets taken over time were divided into two subsets, the first consisting of 22 dates collected during the calibration period from October 2004 to September 2006, and the second with 15 dates collected during the validation period from October 2006 to October 2008. The results showed that if a critical value of 5% for MABE was defined, more than half the sites were temporally stable for both periods, and the number of temporally stable sites generally increased with soil depth. Compared with SDRD, MABE was more suitable for the identification of time‐stable sites for mean SWS prediction. Since the absolute prediction error of drier sites is more sensitive to changes in relative difference in terms of mean SWS prediction, the sites of wet sectors should be preferable for mean SWS prediction for the same changes in relative difference.
Tập 74 Số 3 - Trang 762-773 - 2010