Volumetric soil measures for routine soil testing

Abstract

The design, dimensiors and materials for constructing volumetric soil measures for routine soil testing use are presented. Scoop calibration techniques are also described. Reproducibility of results obtained under routine laboratory, conditions are shown. The measures include volumes of 1.0‐, 2.5‐, 5.0‐ and 10‐ cm³ respectively.     

Effect of tillage treatments upon soil tests for soil acidity,soil phosphorus and soil potassium at three soil depths

Abstract

Soil samples were obtained at 0–3, 3–6, 6–9 and 0–9 inch depths from experimental plots receiving five tillage treatments. Each of two samplers composited approximately six one‐inch cores from each plot. Soil samples were analyzed for acidity, P and K using routine analysis procedures in the University of Illinois Soil Testing Laboratory.

Few significant differences were attributed to sampler and it was concluded that samplers using similar sampling techniques were obtaining soil samples from the same population.

No significant differences in soil acidity at different depths were observed. The different tillage methods did significantly affect soil P at the 0–3 inch depth, but had no significant effect on soil P at deeper depths. Different tillage methods also significantly affected soil K values at different depths.     

The effects of soil composition upon three acrylic soil impregnating resins

Abstract

The relative merits of three acrylic based resins, cured either chemically or by gamma radiation, are examined for use in the impregnation of soils for thin section analysis. The effect of several soil variables (moisture content, pH, texture, presence of expanding minerals or transition metals) upon these resins is discussed to aid in the selection of a suitable resin for the impregnation of various soils.     

Prediction of profile soil moisture for one land use using measurements at a soil depth of other land uses in a karst depression

Purpose

Information on root-zone soil water content (SWC) is essential for vegetation restoration, irrigation scheduling, and hydrological modeling. However, measurements of SWC within a variety of land uses may be time-consuming and labor-costing. This study tested whether SWC at a depth of a land use can be used to predict profile SWC of other land uses in terms of temporal stability analysis at a karst depression area in southwest China.

Materials and methods

A total of 30 datasets of root-zone SWC from 0.1- to 0.5-m depths were collected by time domain reflectometry probes for three typical land uses from March 12 to November 8, 2015.

Results and discussion

Results showed that the profile mean SWC and its associated standard deviation (SD_P) and coefficient of variation (CV_P) differed significantly (P?<?0.05) among the grassland, farmland, and forestland. The profile SWC was more temporally stable according to the apparently lower CV_T in comparison with CV_P. The similarities of the vertical patterns of SWC were strong for the same land uses, while were relatively weak between the different land uses. The SWC measurements of the most temporally stable depth can be used to accurately predict profile SWC for both the same land use and other land uses.

Conclusions

This study further expands the application of the temporal stability analysis and can aid water resource management in areas with diverse land uses.

     

Bioremediation of oil-contaminated soil by combination of soil conditioner and microorganism

Purpose

Oil hydrocarbons are widespread pollutants in soil which pose serious threats to ecological environment. Thus, this study carried out the bioremediation of oil-contaminated soil by using the efficient petroleum-degrading bacteria and soil conditioner, to investigate the changes of physicochemical properties of contaminated soil during bioremediation, reveal the relationship among the exogenous degradation strains and indigenous microbe, and finally illuminate the effects of soil conditioner and microbe on the bioremediation of oil-contaminated soil.

Materials and methods

A PAH-degrading strain named Stenotrophomonas maltophilia was used in this study, which was isolated from an e-waste dismantling area. The soil conditioner in this present study was developed previously by using agricultural wastes, which was in a powdered form and rich in N, P, and K. The simulated experiments were conducted under the control environmental conditions of greenhouse, to study the effects of inoculation and soil conditioner on bioremediation of oil-contaminated soil. Then, the physicochemical properties of soil and the degradation rates of oil were measured at different set times to evaluate the bioremediation effect.

Results and discussion

Adding 1% soil conditioner could significantly improve the soil conditions and offer microorganism enough N, P, and K, which would promote microbial growth and played a key role on bioremediation of oil-contaminated soil. Although in polluted soil, the microorganism could maintain metabolic activity and use the petroleum as carbon source. The soil indigenous microbe was more easily to adapt to the contaminated surrounding. However, when both of them co-existed in soil, they would restrain each other, and go against the oil decomposition. Thus, making two types of microorganisms work to achieve synergy was the key to gain much better remediation effect. Because the indigenous microbe was good at decomposing low molecular compounds and saturated hydrocarbons, while the oil-degrading strains can effectively decompose high molecular weight aromatics.

Conclusions

The soil nutrient and microorganism, including the exogenous oil-degrading strains and the soil indigenous microbe, had an important effect on degradation of petroleum. The addition of soil conditioner, presence of indigenous microbe, and inoculation of oil-degrading strains all were conducive to bioremediation of oil-contaminated site, but the key was to control the proportion and relationship of the three.

Graphical abstract

     

Conductimetric determination of soil urease activity

Abstract

A fast and sensitive method to determine urease activity in soils is described. It involves extraction of NH₄‐N with 1 N. KC1 : 0.01 N HC1 and measurement of NH₄ concentration by electroconductivity using a steady state flow system across a membrane. Sampling was done directly from the extracts with an automatic sampler at 40 samples per hour. The detection limit for NH₄‐N was below 0.05 ppm in the extract. Extracts could be stored at room temperature for 17 hours before measuring NH₄. No post‐treatment hydrolysis of urea occured.     

Portable soil test laboratory results compared to standard soil test values

Abstract

Results from a commercially available portable soil test laboratory were compared to standard soil test procedures used by a public soil testing laboratory. Standard soil tests examined were water extracted NO₃‐N, pH, Acid‐P, NaHCO₃‐P, and ammonium acetate extracted K. Approximately 35 to 55 different soils were used to compare methods for each soil test. Linear regression equations between the portable laboratory soil test values and those from the standard procedures were developed. The r² values for NO₃‐N, pH, Acid‐P, NaHCO₃‐P, and K were 0.970, 0.891, 0.734, 0.742, and 0.887, respectively. The coefficient of variability values for NO₃‐N, pH, Acid‐P, NaHCO₃‐P, and K were 10, 1, 13, 15, and 6%, respectively for the portable laboratory, and 9, 2, 8, 9, and 5%, respectively for the public soil testing laboratory. Multiple regression was used to relate soil properties to soil test results. The R2 values for NO3‐N, pH, Acid‐P, NaHCO₃‐P, and K were 0.970, 0.911, 0.860, 0.940, and 0.936, respectively.     

On-farm comparisons of soil organic carbon under no-tillage and chisel-plow systems

Purpose: Role of no-tillage (NT) in soil conservation has been already established but its influence on soil organic carbon (SOC) is still under debate.

Materials and methods: Three paired sites, with NT and chisel-plow (CT) fields adjacent to each other were selected for this study. Fields were under the same tillage practices for more than 20 years. Fields were sampled up to 90?cm depth to determine SOC and different C pools based on soil CO₂ flux during 86?d of incubation.

Results and conclusion: Significant differences in SOC and its pools were limited within the surface 0–15?cm depth only. Profile SOC did not vary between NT and CT. Tillage had a significant influence on soil C pools but the effect was not consistent across sites.     

Influence of PAH contamination on soil ecological status

Purpose

The purpose of this paper is to study the responses of soil biological parameters as indicator of ecological status on PAH-contaminated soil.

Materials and methods

Studies are conducted on the soils and natural grassy vegetation of monitoring plots subjected to Novocherkassk power station (NPS) emissions. Monitoring plots were established at different distances from the NPS (1.0–20.0 km).

Results and discussion

The level of polycyclic aromatic hydrocarbons (PAHs) around NPS is the highest at the monitoring plot located at distance 1.6 km to the northwest through the prevailing wind direction. Gradually, decrease of PAHs was observed while increasing the distance from the NPS through the prevailing wind direction. Calculation of correlations between PAH level and biological activity parameters of soils showed lack of dependence with total and every PAH content in all 12 studied monitoring plots. The most significant correlations were found between PAH content and enzyme activity in the monitoring plots situated through the prevailing wind direction from NPS.

Conclusions

The main pollution source in the studied area is NPS. It was found that contamination of soil by PAHs has a direct dependence on the activity of all biological communities in chernozems, as well as the activities of dehydrogenase and the phytotoxicity of soils. Inverse correlations have been revealed between the PAH contamination and abundance of soil bacteria.

     

Application of the Berthelot reaction to the determination of ammonium‐N in soil extracts and soil digests

Abstract

The phenol‐hypochlorite‐ammonium reaction of Berthelot can be utilized in manual procedures for the analysis of NH₄‐N in a variety of soils applications, including total N measurement in soils, particle size separates and soluble organic matter fractions, and in measuring NH₄‐N in soil extracts. A simple, convenient, and versatile procedure is described.     

Distribution and availability of fungicide-derived copper in soil aggregates

Purpose

Soil consists of various sizes of aggregates, and different soil aggregates vary in their abilities to adsorb or transport metals. This study aimed to investigate the distribution behaviors of Cu from different fungicides in soil aggregates after a 15-month incubation.

Materials and methods

Bordeaux mixture (CuSO₄/Ca(OH)₂?=?1/1 by weight, BR), copper nitrate (Cu(NO₃)₂·4H₂O, CN), and copper oxychloride (3Cu(OH)₂·CuCl₂, CO) were applied to a representative Chinese Mollisol to reach the Cu content 200 mg kg^?1. Five soil aggregate fractions, i.e., >?2000 μm, 2000–1000 μm, 1000–500 μm, 500–250 μm, and <?250 μm, were obtained by the wet sieving method. The modified Bureau Communautaire de Références (BCR) sequential extraction was applied to assess the Cu distribution among the main soil fractions.

Results and discussion

The highest Cu mass loading was found for the >?2000-μm soil aggregate. The input Cu was mainly in stable fractions, and the highest proportion was found for the residual fraction. The bioavailability and mobility of Cu from different fungicides in soils varied from each other, and they presented an order of CO > CN > BR. High bioavailability and transferring coefficients were found in the <?250-μm and >?2000-μm soil aggregates.

Conclusions

This study indicated that the input Cu from fungicides mainly distributed in the >?2000-μm soil aggregates. Moreover, the CO-derived Cu presented a higher availability than the BR- and CN-derived Cu in the soil.

     

Improved growing conditions through soil aeration

Abstract

A variety of vegetables were grown in a greenhouse in loamy soil or sand with a control watered to 33 bar and treatments aerated for various time intervals to determine effects on yield or other plant characteristics. Statistically significant yield increases were noted for most aerated plant types grown in loam or sand.

For the loam nitrogen leaf tissue of beans was significantly greater than controls for all aerated treatments. This was probably a result of mineralization since it was not found in aerated treatments of soybeans grown in sand.     

Effects of soil texture and gravel content on the infiltration and soil loss of spoil heaps under simulated rainfall

Purpose

Large spoil heaps formed during construction projects have caused serious soil erosion and threatened ecological security. The recent researches on soil erosion of spoil heaps are based on one or several soil types, which can only represent the soil texture category within the limited area, but cannot be used in other larger scale areas. Soil texture and gravel are the main factors affecting infiltration and erosion processes of spoil heaps.

Materials and methods

The runoff plot dimensions were 5.0 m?×?1.0 m?×?0.5 m (length × width × depth). A series of rainfall experiments with a constant rainfall intensity of 1.0 mm min^?1 and a slope gradient of 25° were conducted to investigate the effects of soil texture (sandy, loam, and clay) and gravel mass content (GC, 0%, 10%, 20%, and 30%) on the infiltration and erosion processes. The gravels are divided into 3 classes according to particle size 2–14 mm (small), 14–25 mm (medium), 25–50 mm (large), and the mass ratios were 30%, 50%, and 20%. The duration of each rainfall event was 45 min after runoff out of the plot.

Results and discussion

Results showed that there was a critical GC (10%) improving or controlling infiltration and soil loss. Infiltration rate of sandy spoil heap (SSH) decreased within 45 min, but it decreased first and then stabilized for loam spoil heap (LSH) and clay spoil heap (CSH). Soil loss rate (SLR) of SSH stabilized first and then increased, while it decreased and then stabilized for LSH and CSH. SLR at early stage (0–18 min) was 0.08–0.23 times than it was at later stage (18–45 min) for SSH, but it was 2.06–5.06 times and 1.46–1.95 times for LSH and CSH, respectively. The soil texture had a more significant effect on SLR (P?< 0.05) than GC did. The effects of gravel on SLRs were dependent on soil texture.

Conclusions

The greater the GC was, the lower the SLR was for the spoil heaps. Special attention should be paid to the later stage during rainfall events for SSHs and the early stage for LSHs and CSHs when considering erosion protection measures.

     

Foliage application of nitrogen has less influence on soil microbial biomass and community composition than soil application of nitrogen

Purpose

Many studies have shown the simulated effects of nitrogen (N) deposition on soil microbial community composition by adding N directly to the forest floor but have ignored the N retention process by the canopy. This study was conducted to compare the responses of soil microbial biomass and community composition between soil application of N (SAN) and foliage application of N (FAN).

Materials and methods

A pot experiment was designed with (1) two N application methods (SAN and FAN), (2) three N application levels (5.6, 15.6 and 20.6 g N m^?2 year^?1), and (3) two tree species (Schima superba Gardn. et Champ. and Pinus massoniana Lamb.) following a nested factorial design. Soil microbial biomass and community composition were determined using phospholipid fatty acids (PLFAs) techniques after 1 and 1.5 years of treatments.

Results and discussion

Nitrogen addition increased (P?<?0.05) soil NH₄⁺-N content and soil NO₃^?-N content and decreased (P?<?0.05) soil pH and soil microbial (bacterial, fungal, and actinomycete) biomass for both N application methods. Compared with the SAN treatment, the FAN treatment had higher (P?<?0.05) pH and lower (P?<?0.05) contents of soil NH₄⁺-N and soil NO₃^?-N. Soil microbial biomass and community composition were significantly different between the different N addition levels under the SAN treatment, but they showed no significant difference (P?<?0.05) between the different N addition levels under the FAN treatment. The soil microbial biomass in the S. superba soil was higher (P?<?0.05) than that in the P. massoniana soil for the FAN treatment, with the opposite trend observed under the SAN treatment. Moreover, redundancy analysis showed that soil microorganisms were significantly correlated with soil pH, soil water content, NH₄⁺-N, and NO₃^?-N.

Conclusions

The results showed that N addition affected soil properties, microbial biomass, and the composition of microbial communities; however, the FAN treatment had less influence on soil properties and soil microorganisms than did the SAN treatment over short time scales, and the extent of this effect was different between coniferous and broadleaf trees.

     

Biostimulation as a process aiding tebuconazole degradation in soil

Purpose

The purpose of this study was to compare effects of two biostimulating substances (compost and bird droppings) on the proliferation of microorganisms, enzymatic activity, and resistance of spring barley in soil exposed to tebuconazole fungicide. Both biostimulating substances were also assessed for their efficacy in tebuconazole degradation in soil.

Materials and methods

A pot vegetation experiment was performed with soil belonging to the Eutric Cambisols to test the effect of tebuconazole on the biological activity of soil. Its adverse effect on the biological properties of soil was minimized through the use of biostimulating substances (compost and bird droppings), the effect of which was expressed with the IF_C/BD index. The RCh index was used to determine the effect of tebuconazole on the proliferation of soil microorganisms and enzymes, the BA₂₁ index was used to express soil fertility based on the activity of soil enzymes, whereas the RS index—to express the resistance of spring barley to the administered doses of tebuconazole. Finally, analyses were conducted to determine the efficacy of soil amendment with biostimulating substances in tebuconazole degradation.

Results and discussion

Study results demonstrate that tebuconazole caused significant changes in the proliferation of the tested groups of microorganisms, in the activity of soil enzymes, and in spring barley yield. It was especially noticeable in pots in which the soil was exposed to its highest dose, i.e., 2.499 mg kg^?1. Soil supplementation with bird droppings had a positive effect on the development of soil microorganisms and on the enzymatic activity in the soil. In turn, compost addition to soil exerted various effects on the biological properties of soil. Both biostimulating substances failed to improve spring barley yield. Tebuconazole degradation was more intense in the soil fertilized with bird droppings than with compost.

Conclusions

Results of this study suggest that tebuconazole can affect the stability and health status of soil ecosystems by modifying their biological properties. The high sensitivity of soil microorganisms and enzymes to stress conditions makes them reliable environmental bioindicators. The strive for eliminating the adverse impact of fungicides on soil microbiome through the use of appropriate remediation methods, like, e.g., biostimulation, is of greater concern from the ecological perspective.

     

Nitrogen and water addition regulate soil fungal diversity and co-occurrence networks

Purpose

A field experiment was conducted to assess the role of nitrogen (N) and water addition in shaping soil fungal communities and co-occurrence networks in temperate grassland, northern China.

Materials and methods

We measured soil fungal and plant community compositions, and also soil properties including available N, phosphorus, potassium concentrations, soil pH, and soil moisture. Soil fungal co-occurrence networks were constructed using a random matrix theory–based network inference approach.

Results and discussion

Plant species richness was decreased by N addition but increased by water addition, whereas fungal richness was decreased by N addition. The fungal community composition was significantly changed by both N addition and water addition. Soil fungal α diversity and β diversity were explained by a combination of variations in plant species richness and plant functional composition, and also by changes in soil pH via the soil acidification pathway induced by N and water addition. The fungal co-occurrence networks were more complex and clustered under water addition than that in ambient precipitation.

Conclusions

Our results suggested that plant functional composition, plant species richness, and soil acidification should be incorporated into ecosystem models for predicting soil fungal communities under future climate changes in terrestrial ecosystems.

     

Nitrogen transformation from three soil organic amendments in a sandy soil

Abstract

A sandy soil was amended with various rates (20 – 320 g air-dry weight basis of the amendments per kg of air-dry soil) of chicken manure (CM), sewage sludge (SS), and incinerated sewage sludge (ISS) and incubated for 100 days in a greenhouse at 15% (wt/wt) soil water content. At the beginning of incubation, NH₄-N concentrations varied from 50 – 280 mg kg^?1 in the CM amended soil with negligible amounts of NO₃-N. Subsequently, the concentration of NH₄-N decreased while that of NO₃-N increased rapidly. In soil amended with SS at 20 – 80 g kg^?1 rates, the NO₃-N concentration increased sharply during the first 20 days, followed by a slow rate of increase over the rest of the incubation period. However, at a 160 g kg^?1 SS rate, there were three distinct phases of NO₃-N release which lasted for160 days. In the ISS amended soil, the nitrification process was completed during the initial 30 days, and the concentrations of NH₄-N and NO₃-N were lower than those for the other treatments. The mineralized N across different rates accounted for 20 – 36%, 16 – 40%, and 26 – 50% of the total N applied as CM, SS, and ISS, respectively.     

Forest soil chemical changes following fire

Abstract

Prescribed fire to remove residue in a pine plantation on a sandy soil resulted in increases in pH, P, K and Ca in the top 20 cm of soil during the first 15 months following treatment.     

Swiss concept of soil protection

The maintenance of soils as a basis for sustaining life is an important subject of Swiss environmental policies. A prominent instrument to achieve this goal is the Ordinance of 1998Relating to Impacts on the Soil (OIS). In 13 articles a guiding framework for the protection of the soil is given. For a better understanding of the legal background, SAEFL has published specific commentaries. They explain the intention of the legislator and thus contribute to a consistent and mutual implementation of the soil regulations in practice. Comments are made on respective articles, on the Swiss concept of soil protection and also on the guide, trigger and cleanup values for hazardous substances in the soil. The commentaries are available in German, French and English languages. The extent of the Commentaries (including OIS and excerpts of the Swiss Federal Law of 1983 Relating to the Protection of the Environment) is 44 pages. Mail-address: sol@huwal.admin.ch     

Surface liming effects on soil radiation attenuation properties

Purpose

This study investigates the effects of surface liming on soil attenuation radiation properties. For this, measurements of soil chemical attributes (pH, organic carbon, H+Al, Al³⁺, Ca²⁺, and Mg²⁺) and attenuation radiation parameters (mass attenuation coefficient, μ_m, atomic and electronic cross sections, σ_a and σ_e, effective atomic number and electron density, Z_eff and N_el) were carried out. This aim was motivated by the fact that possible μ_m variation might cause as well variation in the determination of soil physical properties.

Materials and methods

The studied soil, classified as a Dystrudept sity-clay, is located in South Brazil. The trial consisted of five stripes, one of them under pasture and the remaining under no-till system (NTS). Lime rates of 0, 10, 15, and 20 t ha^?1 were broadcast on the NTS soil surface. Disturbed soil samples were collected 30 months after liming at the top (0–10 cm) and subsoil (10–20 cm) layers. Soil chemical attributes were characterized following standard experimental procedures. The soil oxide composition, obtained by EDXRF analysis, was used to calculate μ_m for ²⁴¹Am and ¹³⁷Cs photon energies with XCOM computer code. μ_m values were employed to calculate σ_a, σ_e, Z_eff, and N_el and to predict variations in soil bulk density (ρ) and total porosity (φ).

Results and discussion

Surface liming notably increased contents of soil pH, Ca²⁺, and Mg²⁺ while reduced H+Al and Al³⁺ at the top soil layer, where μ_m, σ_a, σ_e, and Z_eff were also increased with the lime rates. However, at the subsoil layer, liming neither lessened soil acidity nor induced remarkable changes in the attenuation parameters. When using ¹³⁷Cs photon energy, incoherent scattering totally dominated over the radiation interaction processes whereas photoelectric absorption and coherent scattering substantially contributed when ²⁴¹Am photon energy was used. Therefore, the increasing in soil attenuation parameters at the top soil layer was more accentuated considering ²⁴¹Am than ¹³⁷Cs photon energy. Variation in μ_m caused considerable variation in ρ and φ only for ²⁴¹Am photon energy.

Conclusions

The findings regarding the effect of μ_m variation induced by liming on the determination of soil physical properties are extremely relevant because traditionally, in the soil science area, μ_m values are calculated without considering any chemical modification to which the soil can be submitted. Bearing in mind that ρ and φ are important parameters from the agricultural and environmental points of view, not representative measurements of μ_m can lead to biased values of ρ and φ.