Surface Soil Chemical Properties Research Articles

Biological soil crusts enhance the role of non-rainfall water in the water input in alpine sandy land ecosystems

• High amounts of non-rainfall water (10%–15% of water input) occur in the alpine sandy land. • Biological soil crusts increase the daily mean non-rainfall water amount by 23%–30%. • Biological soil crusts enhance non-rainfall water accumulation and dissipation rates by >20%. • The effects of soil crusts can be attributed to changes in soil physicochemical properties. • The principal source of non-rainfall water is atmospheric vapor (∼60%). Non-rainfall water originating from atmospheric and soil vapors is a major water source that supports dryland ecosystem functioning. The alpine sandy land ecosystem is fragile, where biological soil crusts develop widely on the soil surface and play a critical role in regulating surface hydrological processes. Yet, the effects of biological soil crusts on non-rainfall water in the alpine sandy land remain unclear. Therefore, we investigated the patterns and main sources of non-rainfall water under different biological soil crusts in the Qinghai–Tibet Plateau region during the growing season (May–September 2017). Micro-lysimeters were used to measure the amount of non-rainfall water in surface soil (0–10 cm) covered with moss and algae crusts in an interdune area. The results revealed that non-rainfall water occurred for at least 12 h·d −1 (7 p.m.–7 a.m.) and disappeared for 5 h (7 a.m.–12 a.m.). The daily mean non-rainfall water amount ranged between 0.324 and 0.426 mm. Differences in the physical and chemical properties of surface soil caused by biological soil crusts affected the accumulation and dissipation of non-rainfall water. The accumulation and dissipation rates of non-rainfall water under biological soil crusts were respectively 1.22–1.32-fold ( F = 8.01, P < 0.05) and 1.21–1.27-fold ( F = 8.86, P < 0.05) higher than those of bare sand. Biological soil crusts also increased the amount of total non-rainfall water by 23.41%–30.39% ( F = 5.367, P < 0.05), accounting for 2.4%–3.0% of the total water input. Atmospheric vapor condensation was the principal source of non-rainfall water (>60%). Nevertheless, biological soil crusts increased both atmospheric and soil vapor condensation by 29.44%–39.98% ( F = 12.45, P < 0.05) and 13.09–13.94% ( F = 5.91, P < 0.05), respectively. Although non-rainfall water contributed only 10%–15% of the total water input, it constituted a main water input to the ecosystem during the dry period of less rainfall (up to 20%, 19.72 vs. 95.72 mm). In conclusion, non-rainfall water, especially atmospheric vapor condensation, makes a non-negligible contribution to water input in the alpine sandy land ecosystem, for which biological soil crusts enhance the role of non-rainfall water in the water input in surface soil water balance dynamics.

Effects of wind farm on surface soil in desert steppe, China

In recent years, the wind farm has developed rapidly in northern China. However, the construction and operation of wind farm directly or indirectly result in the change of soil structure, thus affecting the regional ecological environment. According to the characteristics of wind turbine engineering, the disturbance area of wind farm can be divided into the core disturbed zone, the secondary disturbed zone and the indirect disturbed zone. A field study was conducted to investigate the physical and chemical properties of surface soil in different disturbed zones. The results show that: (1) soil compaction, soil bulk density and soil salinity of the surface soil are sensitive to wind farm disturbance; compared with the undisturbed zone, there are still significant differences between the core disturbed zone and the secondary disturbed zone; (2) after nearly 10 years of natural recovery, apart from the phosphorus element, there are little differences of surface soil nutrients in different disturbed zones; (3) the impact of wind farm on surface soil will be gradually eliminated over time, but continuous and frequent disturbances caused by engineering maintenance during its operation should be avoided if possible.

スギ・落葉広葉樹混交林の表層土壌の化学性に及ぼす樹幹流、林内雨およびリターの影響

スギ・落葉広葉樹混交林の表層土壌の化学性に及ぼす樹幹流、林内雨およびリターの影響

Effects of soil erosion and seabird activities on chemical properties of surface soils on an oceanic island in Ogasawara Islands, Japan

To conserve indigenous natural ecosystem and help in the recovery of natural vegetation on Nakoudojima Island, which is a subtropical oceanic island in Ogasawara Islands in Japan, we clarified the mechanisms of the changes in soil chemical properties as affected by soil erosion and seabird activities on the island. Under grassland vegetation where influence of feral goat (exotic species) had been severe, the chemical properties of surface soils with a thickness of 5cm were variable even in a small area of 0.375km2; pH(H2O) value range between 4.6 and 6.9, total C content range between 0.36 and 5.62%, total N content range between 0.03 and 0.45%, exchangeable acidity range between 0.5 and 50mmolckg−1, and plant-available phosphate (Bray II P) range between 0.4 and 170mgP2O5100g−1. By clarifying soil profile characteristics under natural and disturbed vegetation and distribution patterns of these soils on the island, the changes in the soil chemical properties were reasonably assigned to the effect of soil erosion caused by feral goats for increased soil exchangeable acidity and decreased soil pH (mainly found in inland area) and to the effect of seabird activities for increased Bray II P and soil exchangeable acidity and decreased soil pH (mainly found in outer rim area with high altitude). It was also clarified that the high soil exchangeable acidity was significantly related to the low productivity of plant biomass for these plots (P<0.01). Soil erosion would have removed surface soils having weak acidity and exposed subsoils having strong acidity to the ground surface, resulting in inhibition of plant growth and delay of vegetation recovery. Based on the findings obtained in the present study, several options were proposed to stop soil erosion and to recover the vegetation, although careful preliminary examination would be necessary for applying them.

Effects of climate and vegetation on soil nutrients and chemistry in the Great Basin studied along a latitudinal-elevational climate gradient

Climate (precipitation and temperature) and vegetation cover strongly influence surface soil chemical and nutrient properties. The objectives of our study were to quantify the responsiveness of soil chemical properties to climate gradients and how the presence of plant canopies modulates this responsiveness in the arid ecosystems of the Great Basin of Nevada, U.S.A. We measured chemical properties of surface soils sampled from between- and under-canopy microsites along a latitudinal-elevational climate gradient with similar underlying geology to quantify responses to climate alone (between-canopy) and to climate and vegetation combined (under-canopy). Only half of the ten soil chemical properties measured (pH, NH4-N, P, Mg2+, and K+) responded significantly to the large climate gradients without the influence of canopy cover. The presence of plant canopies significantly amplified both the climate responses and caused significant responses in additional soil chemical properties to climate gradients, especially for nitrate-N, calcium, total organic C, and total N. Our results suggest that vegetation canopy is a driving factor in defining how soil chemical properties of Great Basin ecosystems respond to climate and anthropogenic climate change.

Spatial Heterogeneity of Soil Chemical Properties in a Subtropical Karst Forest, Southwest China

This study evaluates the spatial heterogeneity of the soil chemical properties of surface soils across a 1 ha old-growth subtropical karst forest in southwest China.

Soil erodibility mapping and its correlation with soil properties in Central Chile

In the Revised Universal Soil Loss Equation (RUSLE), erodibility accounts for the influence of soil properties on soil loss during storm events in upland areas, which is represented by the soil erodibility factor (K). K-factor values are best obtained from long-term direct measurements on natural runoff plots; however, in the absence of field tests, these values can be estimated using relationships based on physical and chemical soil properties. Soil erosion by water is a major concern in Central Chile, and the application of many prediction technologies, such as the RUSLE, is limited due to the lack of information about erodibility factors. Because the direct measurement of K-factor values requires long-term erosion plot studies, the objective of this research was to use existing soil survey data to provide a first approximation of soil erodibility in the region and examine its relationship to soil properties in Central Chile. Erodibility values for a large variety of soil types and surface conditions (535 soil series) were calculated in this study, providing the first soil erodibility map for most of the country's cultivated land areas. Erodibility factors were calculated using two alternative relationships based on physical and chemical properties of surface soils. Results showed that the average K-factor value in the study area was 0.039±0.011tha hha−1MJ−1mm−1, and 67% of soils had values between 0.03 and 0.05tha hha−1MJ−1mm−1. The erodibility factors did not show a pattern with latitude or longitude mainly due to the lack of trends in the soil properties within the study area. Soil erodibility increased with silt content (r=0.607), and soil textures that contained predominantly silt as the primary particles were estimated to be the most vulnerable to water erosion. Organic matter content was not correlated to soil erodibility (r=0.086), and Mollisols and Entisols were the two only taxonomic orders that showed different erodibilities. The results of this study demonstrated the convenience of using silt content instead of clay, organic matter, or taxonomic order in preliminary classifications of water erosion vulnerability in Central Chile or areas with similar soil characteristics.

The influence of individual native trees and grazing regime on soil properties and groundcover patterns in a temperate landscape of New South Wales, Australia

Scattered native trees are a significant ecological resource across the agricultural landscape, yet their numbers are declining due to factors such as dieback, senescence and agricultural activity. This study examined the interactions among Eucalyptus melliodora (Cunn. ex Schauer) trees, vegetation composition and selected surface soil chemical properties in grazed and ungrazed paddocks on the Northern Tablelands of New South Wales, Australia. Four farms on granite soils were examined in grazed and ungrazed treatments. Vegetation composition was assessed, and soil samples were collected in plots beneath the canopy and in adjacent open areas in both north and south directions of the tree canopy. Native grasses dominated the vegetation in both beneath the canopy and open areas, at both grazed and ungrazed sites. However, their composition varied between farms. Several C3 and C4 grasses contributed to the groundcover of the canopy and open sites, but C3 grasses were generally more common under the canopy. Significant differences occurred in soil C, N, P and pH, and vegetation composition between canopy and open areas, and between grazed and ungrazed treatments. Soil P, C and N contents in grazed sites were typically similar to or higher than those in ungrazed sites, and soils were less acid in the ungrazed compared with grazed sites. All soil parameters measured were significantly higher under tree canopies, except P. The tree, soil and vegetation factors were strongly related. This study confirms that individual scattered trees create a distinct mosaic of localised soil improvement, and influence vegetation composition so that paddocks with trees are floristically more diverse than paddocks without trees. The results illustrate the potential benefits of retaining trees for both biodiversity values and livestock production in Australia.

Soil Chemical and Physical Properties That Differentiate Urban Land-Use and Cover Types

We investigated the effects of land use and cover and surface geology on soil properties in Baltimore, MD, with the objectives to: (i) measure the physical and chemical properties of surface soils (0?10 cm) by land use and cover; and (ii) ascertain whether land use and cover explain differences in these properties relative to surface geology. Mean and median values of each variable measured across all plots showed that soil properties varied considerably. Chemical properties generally varied more than physical properties.

Nutritional characteristics in leaves of plants native to tropical peat swamps and heath forests of Central Kalimantan, Indonesia

Thirteen mineral element concentrations in leaf samples of 478 native plants growing in peat swamps and heath forests of Central Kalimantan were detemined. Chemical properties of surface soils in the study sites were also determined. In all sampling sites the mean concentrations of essential macro-elements were variable than that of micro-elements. The chemical properties of surface soils necessitate that the peat podzolic soils are nutrient-limited. However, some native plants growing on these soils show a preference to accumulate excessive concentrations of particular micro-elements, such as Na, Mn, Al, and Si, in their leaves. The results of this study confirm that the concentrations of elements in plant leaves appear to be indicative of site variation and are the result of environmental adaptation. AI, Si, and Na were the principal elements determining the nutritional characteristics of the native plant leaves. However, only AI has clear inter-element relationships for each plant group. Therefore, the relationships between AI-Na and Al-Si in leaves reveal important strategies of plant adaptation to the nutrient-poor ecosystems of peat swamps and heath forests. Native plants belonging to the Eurosid I evolutionary group had very high AI concentrations in their leaves, both in Lahei and Kalampangan peat swamp forests. Combre/ocarpus rotunda/us (Anisophylleaceae family) was predominant in the study sites and, could be regarded as an AI accumulating species (leaf AI concentration within the range of 2,000 - 10,000 mg kg-I). AI-accumulating species likely restrict the accumulation of other mineral elements in their leaves, whereas non AI-accumulating species tend to accumulate other mineral elements in their leaves. Although the mechanism for this eco-physiological adaptation remains unclear, it is suspected that AI-accumulating species (c.f. C. rotunda/us) have developed efficient strategies enabling them to utilize low amounts of essential elements in order to be able to grow in a nutrient-limited environment. Information gathered about AI-accumulation by certain wild plants will useful in selecting appropriate species to rehabilitate damaged peat swamp and heath forests.

Reclaiming sodic soils for wheat production by Prosopis juliflora (Swartz) DC afforestation in India

A green house pot trial was conducted to assess the impact of Prosopis afforestation on the productivity and fertility of degraded sodic soils in Haryana, India. Wheat (Triticum aestivum, L; cultivar HD 2329) plants were grown from seed on top soils collected from a chronosequence of 0, 5, 7, and 30-year-old Prosopis juliflora plantations established on highly sodic soils and a non-sodic reference soil collected from a local farm. The afforestation improved physical and chemical properties of surface soils by decreasing pH, electrical conductivity and exchangeable Na levels, and increasing infiltration capacity, organic C, total N, available P, and exchangeable Ca, Mg, and, K levels. The amelioration effect of the trees on top soil increased with duration of tree occupancy. Soil nutrient status under the 30-year-old plantation was higher than that of the non-sodic farm soil. The reduced soil sodicity and improved fertility contributed to higher germination, survival, growth, and grain yield of wheat plants grown on the Prosopis chronosequence soils, even surpassing the yield attained on the farm soil in the case of 30-year-old plantation soil. Sodium accumulation in the crop declined while N, P, K, Ca, and Mg uptake increased with soil plantation age reflecting the changing nutrient status of the rooting zone due to afforestation. Results confirmed that successful tree plantation may restore the productivity and fertility of highly degraded sodic soils.

Soil formation on the Wallagaraugh Adamellite, southeastern N.S.W., Australia

Soil development on Wallagaraugh Adamellite has been studied within Yambulla State Forest, southeastern Australia. Twenty-five soil profiles have been described and soil chemical and physical properties determined for selected horizons. A geomorphological model is described for elucidating processes affecting soil development on this adamellite parent material. Three main geomorphic environments have been incorporated into this model: residual surfaces found on interfluves and broad hillcrests, transportational surfaces associated with ridges and hill slopes, and depositional surfaces associated with foot-slopes and valley floors. Residual surfaces have developed duplex primary profile forms (yellow podzolics) with structured B horizons of high clay content where exchangeable Al dominates the exchange complex. Transportational surfaces have soils with shallow, uniform to gradational profiles with minimal profile development, and highest, but most variable, concentrations of the exchangeable Ca, K, Na, and total P. Depositional surfaces are characterized by a thick accumulation of uniform, coarse-sandy colluvium-alluvium. Where this surface is stable and well drained, podzols have formed. In contrast, areas of impeded drainage on this depositional surface have humic gley profiles. Concentrations of total P, exchangeable Ca and Mg are low throughout these aggraded soils. The soil-landscape units derived from the geomorphological model are discriminated by multivariate analysis using soil chemical and physical properties. Surface soil chemical properties are shown to be superior in discriminating soil-landscape units to subsoil properties. The mineralogy, geochemistry and texture of the adamellite soil parent material are critical in determining the distinctive geomorphology which, in turn, affects the development of soils in this forest environment.

Fate of Heavy Metals in an Abandoned Lead‐Zinc Tailings Pond: I. Vegetation

AbstractA 50‐yr‐old abandoned tailings pond from a Pb‐Zn processing mill was studied to determine relationships among depositional processes, physical and chemical properties of surface soils, vegetation development, and plant foliar concentrations of Zn, Cd, Cu, and Pb. Five soil/vegetation types were identified ranging from loamy sand with arid land species and 14% aerial vegetation cover at the upper (north) end of the pond to clay loam with wet meadow species and 61% cover at the lower (south) end of the pond. Foliar concentrations of Cd, Zn, Cu and Pb in blue grama [Bouteloua gracilis (H.B.K) Lag.] and creeping bentgrass (Agrostis stolonifera L.) showed no significant differences among the soil/vegetation types in which they dominated. Concentrations of Cd and Pb in foliage of alkali muhly [Muhlenbergia asperifolia (Nees &amp; Meyen) Parodi], a ubiquitous grass species, were higher at the south than the north end of the pond. Metal concentrations in alkali muhly showed significant linear relationships to soil concentrations of metals in the five soil/vegetation types for total Cd (r2 = 0.97; P ≤ 0.001) and Zn (r2 = 0.70; P ≤ 0.05), but exhibited negative exponential relationships for total Cu (r2 = 0.99; P ≤ 0.001) and Pb (r2 = 0.99; P ≤ 0.001). Lead concentrations in grasses within the lower meadows (37.6–69.0 mg kg−1 dry mass) exceeded levels known to be toxic to plants. The results were evaluated in terms of tailings pond reclamation.

Effect of ortho- and pyrophosphates on dissolution of Fe, Al, Si, Ca, and organic C in three soils

Phosphate application changes chemical properties of surface soils, consequently influencing crop nutrient availability and pedological process. Sodium ortho- (OP) or pyrophosphate (PP) was equilibrated with three Quebec soils: an Uplands sand (Orthic-Podzol), a St. Bernard loam (Eutric-Cambisol), and a Dalhousie clay (Humic Gleysol) in 0.03 M KClO4 solution at an initial pH 6.0. Both autoclaved and nonautoclaved soils were used, and dissolution of Fe, Al, Si, Ca and organic C was studied. Concentrations of Fe and Al in OP equilibrated solutions were not detectable. Ca solubility was reduced while dissolution of Si and organic C was increased in the presence of OP. These changes were possibly due to P—Ca precipitates or increased Ca sorption by P, and competition between OP and Si or organic materials for sorption sites. PP enhanced dissolution of Fe, Al, Si and organic C but reduced solubility of Ca. Comparisons showed that PP added to autoclaved soils had greater effects on increasing dissolutions of Fe, Al, Si and organic C and on reducing Ca solubility than OP in both autoclaved and nonautoclaved soils. Autoclaving resulted in greater dissolution of organic C. Dissolved Si with added OP was greater with nonautoclaved soils probably due to more P sorption in the nonautoclaved system, compared with autoclaved soil. Added PP dissolved Fe and Al ions which may ultimately enhance P precipitation by forming less soluble compounds upon hydrolysis of PP to OP.