Aeolian Sandy Research Articles

Nitrogen addition has divergent effects on phosphorus fractions in four types of soils

BackgroundGlobally increasing atmospheric nitrogen (N) deposition has altered soil phosphorus (P) transformations and availability, and thereby influenced structure and function of terrestrial ecosystems. Edaphic characteristics and chemical form of deposited N could be important factors determining impacts of N deposition on soil P transformations, yet the underlying mechanisms remain largely unknown. Objectives of this study were to examine how mineral-N and amino N differently affect P fractions, and identify key soil properties determining N addition impacts on soil P transformations. Considering that amino N is an important component of deposited N and forest soils vary greatly in different regions, the results of present study can guide the management of forests across different soils under ongoing N deposition scenarios.MethodsWe conducted a 60-day laboratory experiment to investigate the effects of N addition (NH4NO3 and glycine) on soil P fractions and related biochemical properties in four representative forest soils (brown, yellow brown, aeolian sandy, and red soils) in China. Glycine and NH4NO3 were separately added at three rates (5, 10 and 20 g N m–2 yr–1).ResultsFirstly, the percent changes in organic P fractions with N addition were significantly greater than changes in inorganic P fractions across all soils. Secondly, the percent changes in P fractions with glycine and NH4NO3 additions were significantly correlated across all soils and treatments. However, glycine addition had significantly greater impacts on organic P fractions than NH4NO3 addition in the aeolian sandy and red soils with low organic carbon content. Thirdly, P fractions responded differently to N addition among the four soils. N-induced changes in microbial biomass and phosphatase activities, pH, exchangeable Ca2+ and Mg2+ contributed differently to the changes in P fractions with N addition in the four soils.ConclusionsThe different responses of P fractions to N addition in the four soils were mainly generated by the differences in extent of microbial N limitation, acid buffering capacity, and cation exchange capacity among the soils. The different impacts of mineral and amino N on soil P fractions can be ascribed to their divergent effects on soil pH, microbial biomass and activities.

Establishment of Salsola tragus on aeolian sands: A Southern Colorado Plateau case study

AbstractRussian-thistle (Salsola tragus L.), is a nonnative, C4 photosynthesizing, annual plant that infests disturbed and natural areas in the arid U.S. Southwest. Land managers of natural areas may need to decide whether a S. tragus infestation is potentially harmful and whether it should be actively managed. One factor informing that decision is an understanding of the conditions under which this weed emerges and establishes and how those processes affect where and when infestations occur. We studied S. tragus establishment on aeolian (windblown) sandy soils at Petrified Forest National Park, AZ. Our sites were a previously disturbed sand sheet and a semistabilized sand dune. Measurements in plots on these sites over two growing seasons revealed a similar number of S. tragus seedlings emerging on both sites early in the 2015 growing season. As the season progressed, S. tragus cover (seedling survival and growth) was lower on the sand dune, except for a plot placed entirely on a coppice mound. In 2016, S. tragus seedling emergence and development of cover, measured on plots at both sites, was exceptionally low, as was summer rainfall. A growth chamber assay of seedling emergence from soil and litter samples collected at each site showed emergence was greatest from samples collected where S. tragus litter remained on the soil surface, and otherwise was infrequent. Our study suggests that S. tragus emergence and early establishment are sensitive to low precipitation and that soil-surface microtopography and grass and shrub cover may be determinants of the spatial pattern of infestation on sandy soils. As aeolian sands occur throughout drylands of the U.S. Southwest, deeper understanding of the conditions under which S. tragus seedlings emerge and establish can inform management of this invasive annual in those habitats.

Sorption of Pb (II) onto

Fine clay particles in the soil, especially for “<1μm effective diameter clay minerals” (<1 μm EDCM) are the most important sink of heavy metals immobilization. However, heavy metal-loaded <1 μm EDCM still pose a threat to the environment based on their high accessibility in various ecosystems. <1 μm EDCM of different loessial soils (i.e. aeolian sandy (AS), manual loessial (ML), cultivated loessial (CL), and dark loessial (DL)) were extracted to identify their binding capacity of Pb(II) ions. Physiochemical characterization of <1 μm EDCM was performed using atomic force microscopy (AFM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). The micro-aggregates features of <1 μm EDCM were further investigated using AFM. Nano morphological features of CL and ML exhibited a roughness shape with higher aggregates formation. However, DL and AS showed a less-aggregated shape with higher potential for accessibility to various ecosystems. Sorption equilibrium time varied greatly among different <1 μm EDCM (4 h with AS, 9 h with ML and DL, and 16 h with CL). Sorption process was mainly controlled by intraparticle diffusion and dominated by chemisorption. The maximum sorption capacity of Pb (II) onto <1 μm EDCM showed the rank as: CL (588.24 mg g−1) > DL (476.19 mg g−1) > ML (416.67 mg g−1) > AS (263.16 mg g−1) based on their grain size, surface area, organo-mineral composition and active functional groups. Data of sorption isotherm showed a high fitting with Temkin model assuming that electrostatic interaction is an important mechanism controlling Pb (II) sorption onto <1 μm EDCM. Finding of this study will provide insights about the vital roles <1 μm EDCM and their aggregates in controlling the bioavailability of heavy metals in aquatic and terrestrial ecosystems.

Transfer of Soil Organic Carbon to Inorganic Carbon in Arid Oasis Based on Stable Carbon Isotope Technique

The northern margin oasis of the Tarim Basin in the central arid region of Asia was selected as the study area. The study analyzed the δ13C values of the SIC(soil inorganic carbon) and distinguished the pedogenic carbonate in soil from the total SIC using the stable carbon isotope techniques and models. Based on the relationship between soil organic carbon and inorganic carbon contents in soil, the transfer of SOC to SIC was discussed. The results showed that the δ13C values of the SIC of 4 types of arid oasis soil were significantly different (P<0.01), the δ13C values of the SIC of aeolian sandy soil was (0.32±0.04)‰, which increased with increase in depth. This indicates that the lithogenic carbonates of the sandy soil are advantageous. The δ13C values of the SIC of irrigated desert soil, brown desert soil, and saline soil were (-0.30±0.24)‰, (-1.96±0.66)‰ and (-1.24±0.49)‰, respectively, and decreased with increase in depth. This indicates that the lithogenic carbonates dominated the irrigated desert soil, and the pedogenic carbonates dominated brown desert and saline soils. In the aeolian sandy, irrigated desert, brown desert, and saline soils, pedogenic carbonate accounted for 1.33%, 4.72%, 15.01%, and 35.71% of SIC, respectively, which were less than 50%. This shows that the level of soil pedogenic carbonates was low in arid oasis. During pedogenic carbonate formation or recrystallization, the aeolian sandy, irrigated desert, brown desert, and saline soils fixed 0.30, 2.44, 4.96, and 12.40 g·kg-1 of soil CO2, respectively, the average amount of CO2 fixed from the atmosphere was 0.18, 0.79, 1.45, and 8.67 g·kg-1, respectively. Furthermore, the transfer of SOC to SIC was 0.06, 0.83, 1.62, and 1.86 g·kg-1, respectively. The total transfer of SOC to SIC was between 0.03 and 2.38 g·kg-1, with an average of 1.09 g·kg-1 of CO2. This shows that the proportion of soil pedogenic carbonates and the contribution of SOC were not high in the arid oasis area.

Geoarchaeology of the Cooper site, northwest Oklahoma: Evidence for multiple Folsom bison kills

AbstractStratified bison kills are rare in Paleoindian contexts on the North American Plains. The Cooper site is a Southern Plains example of an arroyo utilized on three separate occasions by Folsom hunters to trap and kill bison. Geoarchaeological investigations of the Cooper site, including reconstructing the site setting, analyses of the soils and sediments, and detailed stratigraphic descriptions, were employed to characterize the arroyo fill sequence. Three bone beds were found in stratified, sandy loam alluvium beneath eolian fine sandy loam within a paleoarroyo. A buried soil with Btk and Bk horizons formed in the alluvium above the bone beds. The bones are associated with Cg horizons; hence, the bison remains decomposed in anaerobic conditions. Alluvial deposits separating the three bone beds ranged in thickness from 1 to 30 cm and were thickest down the axis of the paleoarroyo. Additional information on the sequence of events was gleaned from the position of a painted bison skull and the condition of the bones. Combined, these lines of evidence point to three kill events and suggest that between one and ten years elapsed between the kills. © 2003 Wiley Periodicals, Inc.

Method and Effect of Studying the Historic Change of the Salinized, Aeolian Sandy and Waterlogged Soils by Using the Aerophotos Tanken at Different Times

Method and Effect of Studying the Historic Change of the Salinized, Aeolian Sandy and Waterlogged Soils by Using the Aerophotos Tanken at Different Times