Contrasting Soil Research Articles

Wheat and Maize Grown on Two Contrasting Zinc-deficient Calcareous Soils Respond Differently to Soil and Foliar Application of Zinc

Wheat and Maize Grown on Two Contrasting Zinc-deficient Calcareous Soils Respond Differently to Soil and Foliar Application of Zinc

Application of Sorbent Amendments in Pfas Immobilization in Two Contrasting Soils

Application of Sorbent Amendments in Pfas Immobilization in Two Contrasting Soils

A comparison of the threshold concentrations of DCD, DMPP and nitrapyrin to reduce urinary nitrogen nitrification rates on pasture soils – a laboratory study

Context Using nitrification inhibitors (NIs) for the targeted management of urine patches, to reduce nitrous oxide (N2O) emissions, requires determining the threshold concentrations of the NIs in urine for effective nitrification inhibition. Aims This study comparatively assessed the threshold concentrations of three NIs: dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP) and 2-chloro-6-(trichloromethyl) pyridine (nitrapyrin) to reduce urinary nitrogen (N) nitrification rates on two contrasting pasture soils. Methods Four rates of each NI (3–27 mg DCD kg−1 soil, 1–13 mg DMPP kg−1 soil and 1–14 mg nitrapyrin kg−1 soil) were added to urine-amended soils and incubated at laboratory room temperature. The amended soils were sampled periodically to monitor changes in mineral-N concentrations. Key results The threshold concentration of DCD (3 mg kg−1 soil, lowest rate tested) was lower than that of nitrapyrin (5–7 mg kg−1 soil) and DMPP (13 mg kg−1 soil, highest rate tested) on both soils. Greater NI effectiveness corresponded to greater NI persistence, with higher (P < 0.05) half-life values observed for DCD (16 ± 2 days, mean ± s.e.) compared with nitrapyrin (10 ± 2 days) and DMPP (9.2 ± 0.3 days). All three NIs persisted longer (P < 0.05) with higher application rates. Conclusions Compared with DCD and nitrapyrin, a higher DMPP concentration was required to effectively inhibit urinary N nitrification rates in the pasture soils. Implications Choosing the ideal application rate of NIs to inhibit nitrification under field condition, and hence mitigate N2O emissions from urine patches, requires consideration of the factors that affect NI loss.

Contrasting Management Techniques and Soil Types Affect Network Connections between Soil Properties and the Tulip Microbiome

Contrasting Management Techniques and Soil Types Affect Network Connections between Soil Properties and the Tulip Microbiome

Contrasting Management Techniques and Soil Types Affect Network Connections between Soil Properties and the Tulip Microbiome

Contrasting Management Techniques and Soil Types Affect Network Connections between Soil Properties and the Tulip Microbiome

Effect of Trichoderma Inoculated Organic Manure on Structural Stability and Hydraulic Properties of Two Texturally Contrasting Soils

Effect of Trichoderma Inoculated Organic Manure on Structural Stability and Hydraulic Properties of Two Texturally Contrasting Soils

Vegetative and productive responses of tabasco pepper to fertigation and plastic mulching

The use of plastic mulching and high frequency hydroponic drip irrigation (intensive production methods) watering cycle may increase tabasco pepper crop production per unit area. To test this hypothesis, two randomized block experiments were conducted in a greenhouse, using a 2 × 4 factorial scheme with two contrasting soil types (sandy loam and loamy soil), two mulching conditions of soil cover (SC), and no soil cover (NC) at four frequencies: 1, 3, 12, and 24 irrigations every three days. The growth and yield pepper components were evaluated and the water use efficiency (WUE) was calculated. Mulching did increase fruit dry mass percentage (FDMP), WUE, and potassium use efficiency (KUE) in sandy loam soil. The greater frequency fertigation did not increase fruit fresh mass (FFM), number of fruits (NF), fruit average mass (FAM), fruit dry mass (FDM), FDMP, or WUE in sandy loam and loamy soils. Tabasco pepper has a permanent shrub growth habit that is somewhat different from horticultural crops, besides it is usually responsive to high frequency irrigation under vegetative intensive growth.

Spatial Simulation of Rice Grain Yields by Empirical Models

Rice grain yields can be affected by several parameters including mostly the climate, cultivars, soil types, and the fertilizer managements. In this study, the performance of two empirical models i.e. AquaCrop and artificial neural network models for simulating the grain yields of two most cultivated varieties including the Shirudi (high-yielding) and Tarom (low-yielding) in three contrasting soil series with different fertilizer managements, were calibrated and validated during 2016 and 2017 rice growing seasons for 459 paddy fields in Mazandaran province, northern Iran. Both models were tested by correlation (R2 ), normalized root mean square error (nRMSE) and coefficient of residual mass (CRM). Results indicate that the performance of both models were affected by the rice cultivar, soil type and soil fertilizer management for both calibration and validation datasets. The ability of both models proved to be satisfactorily applicable for spatial simulation of rice yields in northern Iran, but AquaCrop model was superior. The higher accuracy was observed in AquaCrop for the Shirudi cultivar (R2 =0.89; nRMSE=5.87%; CRM=0.03) compared to the Tarom (R2 =0.67; nRMSE=10.41% and CRM=0.04) for 2017 dataset demonstrating that the AquaCrop has more performance for high-yielding cultivar. Two models had lower accuracy in Esmaeilkola soil series with deep clay soil texture. The best accuracy was observed in paddy fields with optimum fertilizer managements for both models. Overall, it is possible to suggest that AquaCrop model could be used to simulate the spatial distribution of rice grain yield with an acceptable accuracy at province-scale and is applicable for local climate change related scenarios.

Using Nix Color Sensor and Munsell Soil Color Variables to Classify Contrasting Soil Types and Predict Soil Organic Carbon in Eastern India

Using Nix Color Sensor and Munsell Soil Color Variables to Classify Contrasting Soil Types and Predict Soil Organic Carbon in Eastern India

D2O labelling reveals synthesis of small, water-soluble metabolites in soil

Small, water-soluble metabolites (e.g. amino acids, sugars) occupy central positions in biogeochemical cycling, yet for most metabolites we do not know rates of de novo synthesis. The aim of this study was to estimate synthesis of water-soluble metabolites by developing a workflow based on D2O labelling and mass spectrometry quantification of 2H-enrichment. Initial tests established that labelling up to 87 atom% soil water with D2O did not affect soil respiration, suggesting that the smaller (typically ≤60 atom% D2O) labelling of most experiments was unlikely to affect microbial activity. To examine 2H incorporation from D2O, four contrasting soils were spiked with 99.9% D2O leading to 46–61 atom% water present as D2O. Soils were incubated from ten to 240 days before extraction, then isotopologues of a broad range of water-soluble metabolites were quantified by gas chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry. There were dramatic differences among metabolites in the rate of 2H-enrichment. Mannitol, Asp, Asn, Glu, Gln, approached the theoretical maximum 2H enrichment after ten days, indicating that turnover of the metabolite pool due to synthesis occurred at a time scale of around ten days; whereas muramic acid was less than 20% of maximum 2H enrichment after 240 days suggesting turnover due to de novo synthesis was likely on the time scale of several years. Previous studies of the same and similar water-soluble metabolites reported rapid metabolite fluxes into and out of the soil solution led to residence time in solution of 1 h or less. The slow turnover of metabolite pools due to synthesis indicates the fluxes of metabolites in and out of cells is dominated by community-level recycling.

Resistance and Resilience of Soil Nitrogen Cycling to Drought and Heat Stress in Rehabilitated Urban Soils.

In the context of climate change and biodiversity loss, rehabilitation of degraded urban soils is a means of limiting artificialization of terrestrial ecosystems and preventing further degradation of soils. Ecological rehabilitation approaches are available to reinitiate soil functions and enhance plant development. However, little is known about the long-term stability of rehabilitated soils in terms of soil functions when further natural or anthropogenic perturbations occur. Based on rehabilitated urban soils, the present study sought to evaluate the resistance and resilience of soil functions linked to carbon cycling and phosphate dynamics in addition to nitrogen cycling and related microbial communities after a heat and drought stress. A laboratory experiment was conducted in microcosms under controlled temperature conditions, with four contrasted soils collected from a rehabilitated urban brownfield; an initial, non-rehabilitated soil (IS), a technosol with a high organic matter level (HO), and two technosols with less organic matter (LO1 and LO2), together with their respective controls (no stress). Changes in potential denitrification (PDR), nitrification (PNR) rates, and their interactive relationships with soil microbial activities and soil physicochemical properties were determined following a combined heat (40°C) and drought stress period of 21 days. Measurements were carried out immediately after the stress (resistance), and then also 5, 30, and 92 days after soil rewetting at 60% water holding capacity (resilience). Microbial activities involved in soil functions such as carbon cycling and phosphate dynamics proved to be of low resistance in all soils except for IS; however, they were resilient and recovered rapidly after rewetting. On the other hand, the microbial activities and gene abundances that were measured in relation to nitrogen cycling processes showed that for denitrification, activities were more rapidly resilient than gene abundances whereas for nitrification the activities and gene abundances were resilient in the same way. Results suggest that, unless the soils contain high amounts of organic matter, microbial communities in imported soils can be more vulnerable to environmental pressures such as drought and heat than communities already present. This should be considered when rehabilitating degraded soils.

Nitrite accumulation and impairment of N2O reduction explains contrasting soil denitrification phenotypes

Soil denitrification produces the potent greenhouse gas and ozone depleter nitrous oxide (N2O). We previously linked soil N2O emission potential (N2O/N2O + N2) to a continuum of denitrification phenotypes in 20 pasture soils but were unable to determine their proximal cause. At one end of the continuum, soils carried out completely concurrent production and reduction of N2O (concurrent phenotype) while at the other end soils delayed N2O reduction until almost all added nitrate (NO3−) was accumulated as N2O (sequential phenotype). In an unsealed environment, the later phenotype is predicted to emit most added N as N2O. Here we tested the role of delayed N2O reductase synthesis and nitrite (NO2−) based impairment of N2O reduction as determinants of delayed N2O reduction in soils with sequential phenotypes. Nitric oxide (NO), N2O and N2 accumulation were measured in response to added NO3−, NO2− and N2O in anoxic batch incubations of fresh or pre-incubated soil using automated gas chromatography. Successive NO3− additions drove 6 of 7 soils towards increasingly concurrent N2O production/reduction, suggesting delayed production of N2O reductase may be the cause of delayed N2O reduction in initially sequentially denitrifying soils. NO2− addition (2 mM NO3− + 1 mM NO2− vs. 3 mM NO3− control) to sequentially and concurrently denitrifying soil demonstrated that NO2− impairs N2O reduction, even when N2O reductase was fully induced (pre-incubated soils, 1 mM NO2− + 42 μmol N2O vs. 42 μmol N2O control). Further, 2 pieces of evidence suggest that differences in NO2− accumulation are a probable cause of the previously observed denitrification phenotypes. 1) 48 fold higher NO2− accumulation in the sequential vs. concurrent soil in response to 3 mM NO3− addition. 2) the concurrent timing of NO2− depletion/N2O reduction in the sequential soil. However, these observations should be confirmed in a greater number of soils. Inhibition of N2O reductase by NO is proposed as a potential proximal cause of impaired early N2O reduction which could link separate effectors (NO2−, carbon, successive NO3− additions) to a common inhibitory mechanism.

Logging residues promote rapid restoration of soil health after clear-cutting of rubber plantations at two sites with contrasting soils in Africa

Soil health is defined as the soil's capacity to deliver ecosystem functions within environmental constraints. On tree plantations, clear-cutting and land preparation between two crop cycles cause severe physical disturbances to the soil and seriously deplete soil organic carbon and biodiversity. Rubber, one of the main tropical perennial crops worldwide, has a plantation life cycle of 25 to 40 years, with successive replanting cycles on the same plot. The aim of this study was to assess the effects of clear-cutting disturbance on three soil functions (carbon transformation, nutrient cycling and structure maintenance) and their restoration after the planting of the new rubber crop, in two contrasting soil situations (Arenosol and Ferralsol) in Côte d'Ivoire. In this 18-month diachronic study, we intensively measured soil functions under different scenarios as regards the management of logging residues and the use or not of a legume cover crop. We investigated the relationship between soil macrofauna diversity and soil heath. At both sites, clear-cutting and land preparation disturbed carbon transformation and nutrient cycling significantly and, to a lesser extent, structure maintenance function. When logging residues were applied, carbon transformation and structure maintenance functions were fully restored within 12 to 18 months after disturbance. By contrast, no restoration of nutrient cycling was observed over the study period. A legume cover crop mainly improved the restoration of carbon transformation. We found a strong relationship (P ≤ 0.001; R2 = 0.62–0.66) between soil macrofauna diversity and soil health. Our overall results were very similar at the two sites, despite their contrasting soil conditions. Keeping logging residues in the plots and sowing a legume in the inter-row at replanting accelerated the restoration of soil functions after major disturbance caused by clear-cutting and land preparation. Our results confirm the necessity of taking soil macrofauna diversity into account in the management of tropical perennial crops.

Impact of Varied Levels of N, P, and S Stoichiometry on C Mineralization from three Contrasting Soils with or Without Wheat Straw Amendment: a Laboratory Study

Impact of Varied Levels of N, P, and S Stoichiometry on C Mineralization from three Contrasting Soils with or Without Wheat Straw Amendment: a Laboratory Study

Arbuscular Mycorrhizal Fungi Alleviate the Negative Effect of Temperature Stress in Millet Lines with Contrasting Soil Aggregation Potential

Arbuscular Mycorrhizal Fungi Alleviate the Negative Effect of Temperature Stress in Millet Lines with Contrasting Soil Aggregation Potential

Thermal Desorption Temperature Affects Water Retention and Hydraulic Conductivity of Three Contrasting Soils

ABSTRACT Thermal desorption is an effective approach to removing petroleum hydrocarbons from soil. However, the resultant environmental function and revegetation potential of the soil can be reduced by high temperatures. This study evaluated the effect of nine temperatures of heating (60–800°C) on water retention and hydraulic conductivity in three soils of contrasting mineral and physical properties. Fredlund-Xing water release curves were developed using the HYPROP system. Features of the release curves were compared for differences: the water content (%Vol) at which air first enters the macropore volume (AEV), the slope of the rapid desorption portion of the curve, field capacity, and the residual water content. A Hearne sandy loam showed an increase in the %Vol at saturation (0.354 to 0.557 cm3 H2O cm−3 soil), but a decrease in plant available water with increasing temperature. A Rader sand showed a decrease in field capacity and plant available water. A Weswood clay showed no change in field capacity, but an increase in plant available water 10.87 to 18.39 cm3 H2O cm−3 soil through 700°C. Saturated hydraulic conductivity (Ksat) increased for both the Hearne and the Weswood soils with increasing temperature. However, the Rader soil Ksat saw an increase from 0.002 to 0.007 cm s−1 to 450°C but declined to <0.0005 cm s−1 between 500°C and 800°C. This study shows the release curve comparison approach can be effective to quantify changes or differences in soil water relationships by treatment or soil property. Additional insight is provided by electron microscope imaging.

The Rich and the Hard-Working: Roman Villae Near Lake Attersee, Austria

– Large-area high-resolution magnetic and GPR surveys of whole Roman villa sites in Noricum, where no such settlements have been excavated in total so far. – Using image fusion to combine magnetometry and GPR data from low contrast soils to optimise data quality.

Short-Term İmpacts of Biochar Applications on Physico-Mechanic and Chemical Properties of Two Contrasting Textured Soils

The effect of biochar applications on soil properties varies significantly depending on soil textures. Therefore, a pot experiment was carried out to investigate the effects of biochar (BC) amendment on some soil physico-mechanic and chemical properties, such as bulk density (BD), particle density (PD), mean weight diameter (MWD), aggregate stability (AS), Attarberg limits, soil pH, electric conductivity (EC), organic carbon (OC), total nitrogen (TN), and C:N ratio of two different textured calcareous soils (Clay and Sandy Loam). Biochar produced from sunflower residues were mixed with soils at the rate of 0, 1, 2 and 4%. All pots were watered to field capacity and incubated for 30 days. The results showed that biochar improved soil structural properties for both studied soils. Although mean weight diameter (MWD) was increased in clay soil, it was decreased in sandy loam soil. The liquid limit was increased by an increment of BC application rates in both soils, and the plastic limit was increased in single clay soil. BC affected selected soil chemical properties by decreasing soil pH, and increasing the soil EC, OC, TN, and C: N ratio, but no effect was detected on CaCO 3 content in both soils. Organic carbon mineralization ratio increased in the clay soil amended with BC, however, decreased in the sandy loam soil compared with the control sample. As a conclusion, the biochar amendment improved soil physico-mechanic properties of the studied soils. However, the effect on chemical properties was inconsistent

Correction to: Contrasting rhizosphere soil nutrient economy of plants associated with arbuscular mycorrhizal and ectomycorrhizal fungi in karst forests

Correction to: Contrasting rhizosphere soil nutrient economy of plants associated with arbuscular mycorrhizal and ectomycorrhizal fungi in karst forests

Conversion of marginal land into switchgrass conditionally accrues soil carbon but reduces methane consumption

Switchgrass is a deep-rooted perennial native to the US prairies and an attractive feedstock for bioenergy production; when cultivated on marginal soils it can provide a potential mechanism to sequester and accumulate soil carbon (C). However, the impacts of switchgrass establishment on soil biotic/abiotic properties are poorly understood. Additionally, few studies have reported the effects of switchgrass cultivation on marginal lands that have low soil nutrient quality (N/P) or in areas that have experienced high rates of soil erosion. Here, we report a comparative analyses of soil greenhouse gases (GHG), soil chemistry, and microbial communities in two contrasting soil types (with or without switchgrass) over 17 months (1428 soil samples). These soils are highly eroded, ‘Dust Bowl’ remnant field sites in southern Oklahoma, USA. Our results revealed that soil C significantly increased at the sandy-loam (SL) site, but not at the clay-loam (CL) site. Significantly higher CO2 flux was observed from the CL switchgrass site, along with reduced microbial diversity (both alpha and beta). Strikingly, methane (CH4) consumption was significantly reduced by an estimated 39 and 47% at the SL and CL switchgrass sites, respectively. Together, our results suggest that soil C stocks and GHG fluxes are distinctly different at highly degraded sites when switchgrass has been cultivated, implying that carbon balance considerations should be accounted for to fully evaluate the sustainability of deep-rooted perennial grass cultivation in marginal lands.