Microbial community composition of transiently wetted Antarctic Dry Valley soils

During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm3 for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas

Characteristics of soil cover in Poland with special attention paid to the Łódź region

Published in: Natural environment of Poland and its protection in Łódź University Geographical Research, edited by E. Kobojek and T.MarszałThe vast majority (as much as 92%) of soil resources in Poland occur in lowlands and uplands, and only 8% of the area of Poland has the characteristics of mountain soils. Nearly a half (46%) of soils in Poland is created of sandy formations of various origins – usually with a slightly acidic pH. Soils of the Łódź region were mainly formed from sands, and to a lesser degree from clays, silts and organogenic formations. Brown, lessive, podzolic and rusty soils dominate here. Chernozems, fensoils, organogenic soils (peat, muck and silt soils) and rendzinas are also present. Owing to their sandy grain-size composition, they are most often light and very light for cultivation. Most soils are acidified. Socioeconomic and natural conditions have determined the utilisation structure of soils in the Łódź region, where arable lands constitute 60% of the area and grasslands – less than 10%

A comparative study of the phosphorus characteristics of oil palm volcanic soils in Papua New Guinea and New Zealand volcanic soils : a thesis presented in partial fulfillment of the requirements for the Degree of Master of Applied Science in Soil Science at Massey University

Oil Palm (Elaeis guineensis Jacq.) grown on volcanic ash soils in Papua New Guinea (PNG) generally respond well to N fertilisers but shows a lack of consistent response to inorganic phosphorus (P) fertilisers. This is true even on soils with high phosphate retention (PR) and where Olsen P values highlighted in the preliminary survey of PNGOPRA field trial data are very low (90% to at least 60 cm depth). This study was done to characterise the PNG oil palm growing volcanic soils in relation to P responsiveness, to identify P fractions and their relative amounts, to determine the fate of applied P fertilisers and to compare chemical and mineralogical characteristics of PNG soils with some New Zealand (NZ) equivalent soils. Mineralogical analysis indicates that the PNG soils used in this study are relatively young as evidenced by the presence of very high amounts of readily-weatherable volcanic glass in the sand, silt and clay fractions. Soils at Hoskins, Kapiura and Bialla, all in West New Britain (WNB) Province, contain similar amounts and types of primary and secondary minerals. Soils at Bialla are probably older than those at Hoskins and Kapiura and contain large amounts of secondary amorphous minerals (allophane and ferrihydrite) in the clay fraction. Soils at Popondetta are different from those in WNB with high amounts of hornblende and no augite or hypersthene in the heavy mineral fraction. Allophane levels in the clay fraction are high to very high in soil surface layers at Hoskins and Kapiura and at all depths in Bialla soils. At Popondetta, allophane content is very low at all depths PR in all soils and at all depths was highly correlated with acid oxalate extractable Al (Alo) (r = 0.84*) and iron (Feo) (r = 0.89*). The sources of these 2 extracts (allophane and ferrihydrite) are largely responsible for the high PR in the soils studied. High allophane and ferrihydrite levels at all depths in Bialla soils correspond well with very high PR values ( >90%) to at least 2 m depth. Low levels of these 2 minerals in Popondetta soils correspond well with low PR values (30%). Intermediate PR values (60 - 70%) for Hoskins and Kapiura surface soils correlates well with the occurrence of intermediate levels of allophane and ferrihydrite. In all PNG soils, a P fractionation scheme showed that the major P fractions are organic. At Hoskins, NaOH-Po accounts for 38 to 48% of total P. For Kapiura NaOH-Po accounts for approximately 50% of total P, and Bicarb.-Po accounts for 59% of total bicarbonate-extractable P. For Bialla soils, NaOH-Po and Bicarb.-Po comprise between 74 and 76%, on average, of their respective total extracted P for all depths. At Popondetta, NaOH-Po comprises 62% and Bicarb.-Po 63% of their respective total extractable P contents. P fertiliser accumulation in Hoskins and Kapiura soils occurs mostly in organic forms and within the top 10 cm of soil. At Hoskins, 83% of total added P accumulated in the top 10 cm (53% being NaOH-Po) while 17% was found in the next 10 cm depth (31% being NaOH-Po). At Kapiura, 74% of total accumulated P was found in the top 10 cm of soil (61% being NaOH-Po) and 26% within the 20 - 30 cm layer (81% being NaOH-Po). The presence of amorphous minerals explains much of the behaviour of P in trial soils, with the major P source/sink in PNG soils being as organic forms. In relation to soil mineralogical and chemical characteristics, PNG soils were classified into one of the major 3 groups in terms of responsiveness to P fertilisers; (a) soils with very high PR (>90%) and Olsen P values of less than 4 mg/kg which are considered most likely to respond to inorganic P fertilisers e.g. Bialla soil, (b) soils with medium to high PR (60 - 70%) will likely show inconsistent responses to P fertilisers and P responses are most likely to be secondary to N e.g. Hoskins and Kapiura soils and (c) soils with low PR (30 - 40%) which are unlikely to respond to P fertilisers at least in the foreseeable future e.g. Popondetta soils. This study highlights a future need for further study of the dynamics of P nutrient cycling, specifically the mineralisation rates of organic matter and the release of Pi for plant uptake in PNG oil palm growing soils. Also there is a need to re-establish the leaf critical concentration because in PNG soils though leaf levels are generally less than 0.150% DM, palms do not always respond to P fertilisers. This suggests that the "critical" P concentrations under PNG conditions is probably less than the international standard at 0.150% DM. Mineralogical and P sorption characteristics of young volcanic ash soils in NZ are sufficiently similar to those in PNG to provide useful information about the general behaviour of P fertilisers and P reaction products in oil palm production systems

Nitrous oxide consumption potentials of well-drained forest soils in Southern Québec, Canada.

To establish the major controls on N2O consumption by forest soils, we conducted laboratory incubations of 16 samples from four soil types, two organic and two mineral, varying in overlying forest vegetation (sugar maple, American beech and eastern hemlock). The fastest potential consumption of N2O occurred under anoxic conditionswith little soil nitrate and under elevated headspaceN2O concentration. Potential N2O consumption rates were fastest in organic soils under hemlock and beech trees (111 and 75 ng N2O-Ng−1 d−1, respectively) compared to mineral soils under beech and maple trees (45 and 41 ng N2O-N g−1 d−1). Organic soils showed faster N2O consumption rates than mineral soils, possibly due to larger organic C levels and higher C:N ratios. Acetylene treatment confirmed that denitrification was the process underlyingN2Oconsumption. These results suggest that soils regularly consume N2O with varying magnitude, most likely in anoxic microsites throughout the soil profile and that the potential for N2O consumption is larger in organic than in mineral forest soils

Effect of biochars pyrolyzed in N2 and CO2, and feedstock on microbial community in metal(loid)s contaminated soils

Little is known about the effects of applying amendments on soil for immobilizing metal(loid)s on the soil microbial community. Alterations in the microbial community were examined after incubation of treated contaminated soils. One soil was contaminated with Pb and As, a second soil with Cd and Zn. Red pepper stalk (RPS) and biochars produced from RPS in either N2 atmosphere (RPSN) or CO2 atmosphere (RPSC) were applied at a rate of 2.5% to the two soils and incubated for 30 days. Bacterial communities of control and treated soils were characterized by sequencing 16S rRNA genes using the Illumina MiSeq sequencing. In both soils, bacterial richness increased in the amended soils, though somewhat differently between the treatments. Evenness values decreased significantly, and the final overall diversities were reduced. The neutralization of pH, reduced available concentrations of Pb or Cd, and supplementation of available carbon and surface area could be possible factors affecting the community changes. Biochar amendments caused the soil bacterial communities to become more similar than those in the not amended soils. The bacterial community structures at the phylum and genus levels showed that amendment addition might restore the normal bacterial community of soils, and cause soil bacterial communities in contaminated soils to normalize and stabilize

Soils and paleosoils of the Galapagos Islands : what we know and what we don't know, a meta-analysis

Accessible information on Galapagos soils is very limited. Much of the existing, although still scarce, information is several decades old and not easily retrieved. The aim of this paper is to present a critical synthesis. Three local soil-forming factors (parent material, climate, and vegetation) are briefly highlighted, followed by a more detailed discussion of the hypsometric soil sequence on Santa Cruz, the only island where systematic information was recorded by a Belgian geopedological mission in 1962. Five zones are distinguished from the coast toward the top of the island: a dry coastal area, containing superficial and interstitial reddish, smectite-bearing soils between basalt blocks; a transition zone of brown, also smectite-bearing soils; and three subsequent higher zones covered by deeper, brown soils with probably andosolic characteristics. Trace element analyses point to a uniform composition of the parent material and a more progressed weathering on the higher slopes. Micromorphological characteristics of the soils are discussed. Soils of Santa Fe are comparable with those of the coastal zone of Santa Cruz but show higher amounts of P and S, probably of avian origin. Deeper, reddish clayey soils cover San Cristobal and are at least partly pre-Holocene. On the younger islands, no soils seem to be present

Just Passing Through (Beginner version)

The purpose of this resource is to develop an understanding of how water flows through different soils and how it is transformed when it flows through these soils. Students time the flow of water through different soils and observe the amount of water held and also the filtering ability of the soils. They will also observe the filtering ability of soils by noting the clarity of the water before and after it passes through the soil. Educational levels: Primary elementary, Intermediate elementary

Soil and My Backyard

The purpose of this resource is to explore soil and soil properties. Students discover the variability of soils, derive relationships among soils and the soil forming factors, and link the GLOBE Soil Investigation to the students. local environment. Students use soil samples from their homes to identify properties that characterize their soils. They compare and contrast their soils to those of their classmates. As a class, students describe relationships between the properties of their soils and how and where they were sampled. Older students construct a soil classification schema. Educational levels: Primary elementary, Intermediate elementary, Middle school, High school