Soil Processes Research Articles

Emissions of N2O AND CH4 gases and soil bacterial community under integrated systems in the tropical region

The use of integrated production systems is widespread, mainly in tropical areas. This practice could contribute to soil conservation, increasing biodiversity and environmental services while reducing greenhouse gases emissions. The present work assessed bacterial biodiversity and correlations with nitrous oxide (N2O) and methane (CH4) emissions in soils under integrated production systems. Analyses of bacterial diversity and community structure were carried out using DGGE (denaturing gradient gel electrophoresis). Samples for the evaluation of greenhouse gases were collected in the field and measured using a gas chromatograph. The assessed treatments in a rainy and dry season were: crop (L), pasture (P), planted eucalypt forests (F), pasture followed by crop (IPL), crop followed by pasture (ILP), crop with forest (ILF); pasture with forests (IPF); crop with forest followed by pasture with forests, pasture with forests followed by crop with forest and crop, grassland and forest. In the rainy season, most N2O emissions occurred in the ILP with an average flow of 42.33 µg N m−2 h−1, and the lowest flow was observed in the ILF, with an average flow of 5.53 µg N m−2 h−1. In the dry season, higher emission occurred in the IPL, with an average flow of 4.17 ug N m−2 h−1. In this period, we observed gas consumption in F, the highest N2O consumer with a flow of −4.14 µg N m−2 h−1. In both seasons, CH4 was consumed, with IPF as the most significant consumer with an average flow of −14.19 µg C m−2 h 1(dry); F was the most significant consumer with an average flow −12.32 µg of C m−2 h−1. Bacterial community structure was affected by the agricultural production system and the seasons. Methane emissions and pH showed a correlation with bacterial diversity in different treatments. In contrast, nitrous oxide was negatively correlated with bacterial diversity. Based on our results, we suggest that integrated production systems and plant coverage modulate soil bacterial community structure and biodiversity which, in turn, affect soil processes related to higher or lower methane and nitrous oxide emissions.

Esterified Conditioner and Repairing Agent for Salinity Affected Agricultural Soil of India

Various bio-conversion reactions given by lipases such as hydrolysis, transesterification, esterification, alcohoysis, acidolysis and aminolysis. The potential esterification process in soil plays important role not only as a fertilizer or nutrient but also act as a modulator to alter the conditions of soil and help in uptake of nutrient and minerals. This potential formulation accumulates micro-nutrients and mineral that promotes growth of plants. The trials of vegetable plants and grains shown significant increase in crop yield per hector area. The bulk density and field capacity of the soil are also significantly change and act as soil conditioner also influence the growth of plants. The micronutrients uptake of plant helps optimize the soil pH and improve the soil conditions. The inventors of present invention tested formulation as plant growth promoters that enhance crop characteristics like panicle length, plant height, grain or fruit yield and add to nutrient value of the crop. Our product is fatty acid composite which play crucial role as plant growth promoter along with reducing seed germination time and increasing plant crop yield, it also beneficial to work under water stress conditions and variant geo-climatic conditions.

Tannins and Climate Change: Are Tannins Able To Stabilize Carbon in the Soil?

The interaction between tannins and proteins has been studied intensively for more than half a century as a result of its significance for various applications. In chemical ecology, tannins are involved in response to environmental stress, including biotic (pathogens and herbivores) and abiotic (e.g., drought) stress, and in carbon (C) and nutrient cycling. This perspective summarizes the newest insights into the role of tannins in soil processes, including the interaction with fungi leading to C stabilization. Recent knowledge presented here may help to optimize land management to increase or preserve soil C to mitigate climate change.

Common soil history is more important than plant history for arbuscular mycorrhizal community assembly in an experimental grassland diversity gradient

The relationship between biodiversity and ecosystem functioning strengthens with ecosystem age. However, the interplay between the plant diversity - ecosystem functioning relationship and Glomeromycotinian arbuscular mycorrhizal fungi (AMF) community assembly has not yet been scrutinized in this context, despite AMF’s role in plant survival and niche exploration. We study the development of AMF communities by disentangling soil- and plant-driven effects from calendar year effects. Within a long-term grassland biodiversity experiment, the pre-existing plant communities of varying plant diversity were re-established as split plots with combinations of common plant and soil histories: split plots with neither common plant nor soil history, with only soil but no plant history, and with both common plant and soil history. We found that bulk soil AMF communities were primarily shaped by common soil history, and additional common plant history had little effect. Further, the steepness of AMF diversity and plant diversity relationship did not strengthen over time, but AMF community evenness increased with common history. Specialisation of AMF towards plant species was low throughout, giving no indication of AMF communities specialising or diversifying over time. The potential of bulk soil AMF as mediators of variation in plant and microbial biomass over time and hence as drivers of biodiversity and ecosystem relationships was low. Our results suggest that soil processes may be key for the build-up of plant community-specific mycorrhizal communities with likely feedback effects on ecosystem productivity, but the plant-available mycorrhizal pool in bulk soil itself does not explain the strengthening of biodiversity and ecosystem relationships over time.

Determining N2O and N2 fluxes in relation to winter wheat and sugar beet growth and development using the improved 15N gas flux method on the field scale

AbstractThe objectives of this field trial were to collect reliable measurement data on N2 emissions and N2O/(N2O + N2) ratios in typical German crops in relation to crop development and to provide a dataset to test and improve biogeochemical models. N2O and N2 emissions in winter wheat (WW, Triticum aestivum L.) and sugar beet (SB, Beta vulgaris subsp. vulgaris) were measured using the improved 15N gas flux method with helium–oxygen flushing (80:20) to reduce the atmospheric N2 background to < 2%. To estimate total N2O and N2 production in soil, production-diffusion modelling was applied. Soil samples were taken in regular intervals and analyzed for mineral N (NO3− and NH4+) and water-extractable Corg content. In addition, we monitored soil moisture, crop development, plant N uptake, N transformation processes in soil, and N translocation to deeper soil layers. Our best estimates for cumulative N2O + N2 losses were 860.4 ± 220.9 mg N m−2 and 553.1 ± 96.3 mg N m−2 over the experimental period of 189 and 161 days with total N2O/(N2O + N2) ratios of 0.12 and 0.15 for WW and SB, respectively. Growing plants affected all controlling factors of denitrification, and dynamics clearly differed between crop species. Overall, N2O and N2 emissions were highest when plant N and water uptake were low, i.e., during early growth stages, ripening, and after harvest. We present the first dataset of a plot-scale field study employing the improved 15N gas flux method over a growing season showing that drivers for N2O and N2O + N2 fluxes differ between crop species and change throughout the growing season.

Nontarget effects of pre‐emergent herbicides and a bioherbicide on soil resources, processes, and communities

Community‐type conversions, such as replacement of perennials by exotic annual grasses in semiarid desert communities, are occurring due to plant invasions that often create positive plant–soil feedbacks, which favor invaders and make restoration of native perennials difficult. Exotic annual grass control measures, such as pre‐emergent herbicides, can also alter soil ecosystems directly or indirectly (i.e. via the plant community), yet there are few studies on the topic in natural, non‐cropped landscapes. We asked how spray treatments applied to soil post‐fire with the intention of inhibiting invasive annual grasses (such as Bromus tectorum L.) and releasing existing native perennial grasses affected soil resources, a microbial process, and invertebrates in three climatically varied sagebrush steppe sites. Spray treatments included chemical herbicides (imazapic and rimsulfuron) that strongly affected plant communities and a bioherbicide (Pseudomonas fluorescens strain D7) that did not. Chemical herbicides increased soil mineral nitrogen in proportion to their negative effects on plant cover for 2 years after treatments in all sites and increased soil water and net N mineralization (measured at one site) but did not affect total carbon, nitrogen, or organic matter. Invertebrate responses to herbicides varied by site, and invertebrates increased with chemical herbicides at the highest, wettest site. We show that herbicide treatments can exacerbate pulses of mineral nutrients, which previous studies have shown can weaken ecosystem resistance to invasion. Thus, restoration strategies that increase the likelihood that desired plants can capture mineralized nutrients after herbicide application will likely be more successful.

A theory for context-dependent effects of mammalian trampling on ecosystem nitrogen cycling.

Large mammalian herbivores substantially impact ecosystem functioning. As their populations are dramatically altered globally, disentangling their consumptive and non-consumptive effects is critical to advance mechanistic understanding and improve prediction of effects over ecosystem and Earth-system spatial extents. Mathematical models have played an important role in clarifying potential mechanisms of herbivore zoogeochemistry, based mostly on their consumptive effects as primary consumers and recyclers of organic and inorganic matter via defecation and urination. Trampling is a ubiquitous effect among walking vertebrates, but the consequences and potential mechanisms of trampling in diverse environments remain poorly understood. We derive a novel mathematical model of large mammalian herbivore effects on ecosystem nitrogen cycling, focusing on how trampling and environmental context impact soil processes. We model herbivore trampling with a linear positive or negative additive effect on soil-mediated nitrogen cycling processes. Combining analytical and numerical analyses, we find trampling by large mammalian herbivores is likely to decrease nitrogen mineralisation rate across diverse environments, such as temperate grassland and boreal forest. These effects are mediated by multiple potential mechanisms, including trampling-induced changes to detritivore biomass and functioning (e.g. rate of organic matter consumption). We also uncover scenarios where trampling can increase nitrogen mineralisation rate, contingent on the environment-specific relative sensitivity of detritivore mineral-nitrogen release and detritivore mortality, to trampling. In contrast to some consumptive mechanisms, our results suggest the pace of soil nitrogen cycling prior to trampling has little influence over the direction of the trampling net effect on nitrogen mineralisation, but that net effects may be greater in slow-cycling systems (e.g. boreal forests) than in fast-cycling systems (e.g. grasslands). Our model clarifies the potential consequences of previously overlooked mechanisms of zoogeochemistry that are common to all terrestrial biomes. Our results provide empirically testable predictions to guide future progress in empirical and theoretical studies of herbivore effects in diverse environmental contexts. Resolving ecological contingencies around animal consumptive and non-consumptive effects will improve whole-ecosystem management efforts such as restoration and rewilding.

An agrogeophysical modelling framework for the detection of soil compaction spatial variability due to grazing using field‐scale electromagnetic induction data

AbstractSoil compaction is a regarded as a major environmental and economical hazard, degrading soils across the world. Changes in soil properties due to compaction are known to lead to decrease in biomass and increase in greenhouse gas emissions, nutrient leaching and soil erosion. Quantifying adverse impacts of soil compaction and developing strategies for amelioration relies on an understanding of soil compaction extent and temporal variability. The main indicators of soil compaction (i.e., reduction of pore space, increase in bulk density and decrease in soil transport properties) are relatively easy to quantify in laboratory conditions but such traditional point‐based methods offer little information on soil compaction extent at the field scale. Recently, geophysical methods have been proposed to provide non‐invasive information about soil compaction. In this work, we developed an agrogeophysical modelling framework to help address the challenges of characterizing soil compaction across grazing paddocks using electromagnetic induction (EMI) data. By integrative modelling of grazing, soil compaction, soil processes and EMI resistivity anomalies, we demonstrate how spatial patterns of EMI observations can be linked to management leading to soil compaction and concurrent modifications of soil functions. The model was tested in a dairy farm in the midlands of Ireland that has been grazed for decades and shows clear signatures of grazing‐induced compaction. EMI data were collected in the summer of 2021 and autumn of 2022 under dry and wet soil moisture conditions, respectively. For both years, we observed decreases of apparent electrical resistivity at locations that with visible signatures of compaction such as decreased vegetation and water ponding (e.g., near the water troughs and gates). A machine learning algorithm was used to cluster EMI data with three unique cluster signatures assumed to be representative of heavy, moderately, and non‐compacted field zones. We conducted 1D process‐based simulations corresponding to non‐compacted and compacted soils. The modelled EMI signatures agree qualitatively and quantitatively with the measured EMI data, linking decreased electrical resistivities to zones that were visibly compacted. By providing a theoretical framework based on mechanistic modelling of soil management and compaction, our work may provide a strategy for utilizing EMI data for detection of soil degradation due to compaction.

Optimizing chickpea growth: Unveiling the interplay of arbuscular mycorrhizal fungi and rhizobium for sustainable agriculture

AbstractArbuscular mycorrhizal fungi (AMF) are beneficial root symbionts that form mutual partnerships with approximately 90% of plants. They provide water, nutrients, and protection from stresses while receiving photosynthetic products from the host plants. These fungi are essential components of the soil ecosystem, and their absence or decline can negatively impact ecosystem efficiency. In chickpea cultivation, the interaction between AMF and rhizobium is vital for soil processes and plant productivity. Alongside other beneficial microorganisms in the rhizosphere, they enhance the acquisition of essential nutrients like nitrogen (N) and phosphorus (P), promoting chickpea growth and development. These interactions are particularly crucial in low‐input, eco‐friendly agricultural systems that rely on biological processes to sustain soil quality and productivity without heavy use of agrochemicals. The combination of root nodules' N‐fixation and AMF synergism also improves plant P nutrition and stimulates the proliferation of phosphate‐solubilizing fungi. However, genetic diversity among native strains and their genes/enzymes can influence the interactions between AMF and rhizobium. To achieve sustainable chickpea production, it is crucial to gain a deeper understanding of these interactions, allowing optimized combinations of microorganisms to be used as effective soil inoculants for promoting plant growth and fitness. This review aims to provide insights into the mechanistic interactions of AMF and rhizobium, their impact on rhizosphere soil health, and the role of environmental factors in regulating chickpea productivity and sustainability.

Estimating soil hydraulic properties from oven-dry to full saturation using shortwave infrared imaging and inverse modeling

To minimize uncertainty related to soil processes in extreme events, we need accurate soil hydraulic properties across the entire range of soil water content. However, conventional methods are time-consuming and limited to specific ranges. To estimate soil hydraulic properties throughout the entire range, we conducted inverse modeling using upward infiltration experiments, where a shortwave infrared imaging camera was used to obtain high-resolution soil moisture data in space and time. Because the commonly used van Genuchten–Mualemmodel is unsuitable for describing soil hydraulic properties for dry conditions, we tested an alternative model, the Peters-Durner-Iden model, which considers both capillary and film water. The inverse modeling successfully estimated soil hydraulic properties for sandy loam and loam soils, and we demonstrated that the Peters-Durner-Iden model captured soil moisture dynamics better than the van Genuchten–Mualemmodel for dry conditions. However, both models could not adequately describe the soil moisture data for the other soils. The direct observation of the water flow via shortwave infrared images clarified that the reduced success was because of violating the one-dimensional flow assumption for coarse-textured soils and the micro-heterogeneity in soil hydraulic properties for soils with fine silt and clay materials.

Research on hydro-thermal coupling model of canal foundation soil based on particle grading curve predicting soil-water characteristic curve

Hydro-thermal coupling is the essence of the freeze-thaw process, and theoretical studies of this coupled process have been hot topics in the field of frozen soil. Darcy's law of unsaturated soil water flow, heat conduction theory, and relative saturation and solid-liquid ratio are based on this paper. According to the principle that the cumulative curve of particle gradation of canal foundation soil is similar to soil-water properties. A soil-water characteristic curve is derived using the cumulative particle gradation curve. VG model is then used to fit soil-water characteristic curves to obtain the canal foundation soil's hydraulic characteristic parameters, and the established hydro-thermal coupling model is modified to reflect canal foundation soil hydro-thermal evolution more objectively. A closed system one-way freezing test method is used to verify the feasibility of the proposed method in this part. The results show that the optimal parameters of the VG model of the subsoil are a = 0.06, n = 1.2, and m = 0.17, and the temperature and water fields obtained from the simulation are in good agreement with the measured data, showing the utility of the hydro-thermal coupling model in predicting hydraulic parameters. Analysis of the multi-field interaction mechanism and dynamic coupling process of the canal foundation soil during freezing and thawing. This has great importance for preventing freezing damage in canals and protecting agricultural safety.

Insight into the electrochemical process of EDTA-assisted soil washing effluent under alternating current

EDTA has been widely utilized as a chelating agent in soil heavy metal remediation, due to its strong coordination capability. Electrochemical deposition is a promising avenue to treat soil washing effluent. However, the impact of advanced electrochemical techniques on EDTA remains incompletely understood. Herein, we present a pioneering approach, utilizing a dual-chamber electrolytic cell and alternating current (AC) power supply. This approach achieves concurrent removal of M-EDTA while efficiently recovering heavy metal and recycling EDTA. Results demonstrate AC displays superior heavy metal removal capability for Cu, Pb, and Cd compare to direct current (DC), with EDTA decomposition mainly occurring in the anolyte. Substituting DC with AC and employing the dual-chamber electrolytic cell significantly enhances EDTA recovery efficiency from 47% to an impressive 96.8%. XPS and Raman spectra reveal an enhanced oxidative surface of the graphite anode under AC, which diminishes the decomposition of EDTA. Long-term experiments validate that this strategy boosts EDTA cyclability to 20 cycles with an outstanding 84% recovery efficiency and negligible electrode corrosion, surpassing the 8 cycles under the traditional strategy. This study innovatively combines cell design and electrochemical techniques, remarkably improving the reusability of EDTA and anode, offering valuable insights for chelate-related applications.

Spatializing soil elemental concentration as measured by X-ray fluorescence analysis using remote sensing data

Spatial soil information has significantly contributed to public policy and planning. The use of X-ray fluorescence spectrometry (XRF) in soil science, primarily in laboratory settings or for isolated point analyses, has been well documented. This study broadens the application of XRF data by integrating it with remote sensing data for a comprehensive understanding of soil patterns and processes. Focusing on a 2574 km2 area in Brazil, we utilized a lab-based XRF instrument to measure the total concentrations of key chemical elements in the soil, such as Al, Si, Ti, and Fe. These geochemical data were then spatialized using the digital soil mapping (DSM) framework. We employed a synthetic bare soil image and elevation data as covariates in the analysis. The spatial accuracy assessment yielded R2 values ranging from 0.65 to 0.81 for Fe, 0.62 to 0.78 for Ti, 0.52 to 0.63 for Si, and 0.48 to 0.63 for Al. The digital soil maps of geochemical elements aligned well with existing pedological, and geological maps as evaluated using multiple correspondence analysis. The integration of spatialized XRF data with DSM and remote sensing techniques shows significant promise in assessing soil variations across landscapes based on their chemical composition.

Ungulate herbivores promote contrasting modifications of soil properties and organic carbon stabilization in a grazed grassland versus rewilded woodland environment

Large vertebrate herbivores are ecosystem engineers, provoking cascading effects on soil properties through modifications of plant communities as well as direct modulation of organic matter incorporated into soils. However, most studies have been carried out with domestic ungulates in grasslands, and the effects which predominate in grasslands may not be generalizable to other ecosystems. It is not well understood how trophic rewilding with wild ungulates may affect soil processes, especially in non-grassland systems albeit rewilding of natural areas is a process associated with larger trends of land abandonment, shrub encroachment or land use change. In this study we investigated ungulate herbivore exclusion in two geographically and pedo-climatically equivalent but ecologically distinct contexts: a Mediterranean grassland with domesticated herbivores, and a reforested area populated by a community of wild ungulates. In each context, long-term herbivore exclusion zones were used to understand the effect of herbivores on soil properties and particularly on soil organic carbon (SOC). Samples from the topsoil (0–5 cm) were taken inside and outside the exclosures distributed between the two contexts, and ecosystem-level effects and responses to grazing were investigated. We found that soil properties’ response to grazing depended on the ecological context in which the grazing occurred. SOC contents in the grassland increased by up to 37% with grazing, while grazing reduced SOC concentrations by 23% in the rewilded area. In both cases, grazing was also associated with significant alterations of soil microbial biomass, the microbial metabolic quotient (qCO2), and aggregate stability, but the effects were opposite: On one hand, domesticated herbivores in the grassland positively influenced carbon stabilization which was strongly associated with soil microbial processes and characteristics, and additionally the proportion of stable macroaggregates was increased. In contrast, wild ungulate herbivory in the forest ecosystem reduced SOC concentrations, accompanied by decreased microbial biomass and increased microbial maintenance costs, and stable macroaggregates were reduced. The results indicate the importance of ecological context in determining the effect of herbivores on soil properties and processes and suggest that the directionality of effects on SOC may change owing to the predominance of different mechanisms of SOC stabilization. Consequently, this study provides evidence that the management of ungulates in rangelands or forests can be associated with different outcomes as related to crucial soil properties such as SOC contents and aggregation.

Rehydration under extreme drought conditions affected rhizosphere microorganisms more than bulk soil in broomcorn millet farmland

Rehydration is a primary adaptation strategy for alleviating the detrimental effects of drought on crop growth. However, the effects of rehydration on microbial communities in various compartments under drought conditions remain poorly understood. Herein, we explored the response patterns of bacterial and fungal community composition, diversity, ecological network, and assembly process in the bulk soil and rhizosphere of broomcorn millet farmland at 5, 10, 20, and 30 days after rehydration during drought conditions. Compared to drought, rehydration significantly decreased the organic matter (OM), total nitrogen (TN), available potassium (AK), available phosphorus (AP), nitrate nitrogen (NO3--N), and ammonium nitrogen (NH4+-N) contents in rhizosphere, but had no obvious influences on the OM and TN contents in bulk soil on the four sampling days. In the rhizosphere of broomcorn millet field, Firmicutes and Actinobacteria were enriched in drought condition, but Proteobacteria and Bacteroidetes were enriched in rehydration regime. Compared to drought, the relative abundances of Eurotiomycetes, Dothideomycetes, Mortierellomycetes, and Leotiomycetes were enhanced, but Sordariomycetes was reduced on the 5th and 10th days after rehydration. Rehydration increased the bacterial and fungal observed ASVs and Shannon index in the rhizosphere to varying degrees, but had little effect on the bulk soil. Null-model analysis indicated that rehydration deceased the stochastic process of fungal communities in the bulk soil, whereas had no influence on deterministic process of bacterial community in the bulk soil and rhizosphere. More importantly, rhizosphere properties had a greater impact on the bacterial and fungal community composition, diversity, and assembly process than bulk soil. Network analysis revealed that rehydration improved the interconnected taxa in the rhizosphere bacterial network, but reduced microbial interactions in the rhizosphere fungal network compared to drought. This work provides a theoretical foundation for elucidating the role of rehydration regime in governing the ecological services of microbiome of broomcorn millet farmland under drought conditions.

Below-ground arthropod diversity in conventional and organic vineyards: A review

Viticulture is one of the most important agricultural sectors in the Mediterranean area but also one with substantial impact on the soil ecosystem. Some of the most common practices in viticulture, such as tillage, inter-row management, fertilization and use of pesticides, can have important effects on soil communities. The latter significantly contribute to several fundamental soil processes such as decomposition, nutrient and carbon cycling, and microbiota regulation. In perspective, it is therefore necessary to assess the effects of agronomical practices on soil biological communities. The increasing shift towards organic viticulture is seen as a promising management model to maintain soil functionality and preserve soil biodiversity. Below, we present an appraisal of the main practices in conventional and organic viticulture and their possible effects on soil mesofauna. Understanding the extent to which organic practices contribute to maintaining/altering soil functionality and biodiversity is a fundamental step towards the development of an environmentally sustainable viticulture.

Impact of iron-modified biochars on soil nitrous oxide emissions: Variations with iron salts and soil fertility

Nitrous oxide (N2O) emissions from soils are a significant environmental concern due to their contribution to greenhouse gas emissions. Biochar has been considered as a promising soil amendment for its potential to influence soil processes. Iron modification of biochar has been extensively discussed for its ability to enhance adsorption of pollutants, yet its impact on mitigating soil N2O emissions remains poorly understood. In the present study, corn straw (CB) and wood (WB) biochars were treated with FeSO4/FeCl3 (SCB and SWB) and Fe(NO3)3 (NCB and NWB). The effects of these biochars on soil N2O emissions were investigated using soils with varying fertility levels over a 35-day incubation period at 20 °C. Results revealed significant variations in biochar surface chemistry depending on biochar feedstock and iron salts. Compared to pristine biochars, NWB and NCB exhibited higher pH, total N content, and dissolved NO3–N concentrations (246 ± 17 and 298 ± 35 mg kg−1, respectively), but lower bulk and surface C content. In contrast, SWB and SCB demonstrated acidic pH and elevated dissolved NH4–N concentrations (5.38 ± 0.43 and 4.19 ± 0.22 mg kg−1, respectively). In forest soils, NWB and NCB increased cumulative N2O emission by 28.5% and 67.0%, respectively, likely due to the introduction of mineral nitrogen evidenced by significant positive correlation with NO3–N or NH4–N. Conversely, SWB and SCB reduced emissions in the same soil by 28.5% and 6.9%, respectively. In agricultural soil, most biochars, except SWB, enhanced N2O emissions, possibly through the release of labile organic carbon facilitating denitrification. These findings underscore the significance of changes in biochar surface chemistry and the associated potential risk in triggering soil N2O emissions. This study highlights the need for a balanced design of biochar that considers both engineering benefits and climate change mitigation.

Heterogeneous co-supplies of phosphorus, sulfur and carbon enhance phosphorus availability by improving rhizosphere processes in a calcareous soil

Heterogeneous co-supplies of phosphorus, sulfur and carbon enhance phosphorus availability by improving rhizosphere processes in a calcareous soil

Effects of zinc oxide nanoparticles on carbon mineralization kinetics and microbial attributes in plant residue-amended soils

This study was designed to determine the impacts of different ZnO-NPs concentrations (100–1000 mg kg−1 soil) on soil carbon (C) mineralization of a calcareous soil amended with alfalfa hay (AH) and wheat straw (WS). In addition, C mineralization kinetics in the residue-amended soils were described using different kinetic models and the impacts of ZnO-NPs on the kinetic parameters were investigated. The microbial biomass C (MBC) and basal respiration (BR) were also compared in the treated and control soil samples. The findings revealed a significant reduction in total cumulative mineralized C (Cmin) in soil amended with AH at ZnO-NPs concentrations of 100 and 200 mg−1 kg soil. Similarly, in soil samples amended with WS, the Cmin value demonstrated a significant decrease across all ZnO-NPs concentrations, except for the lowest concentration of 100 mg−1 kg soil. The results of kinetic analysis using the double first-order model showed that the introduction of ZnO-NPs led to an increase of up to 147 % in the amount of C mineralization during the initial fast phase, while it also resulted in a reduction of up to 27.3 % in C mineralization during the subsequent slow phase. Moreover, the presence of ZnO-NPs in the soil resulted in a noteworthy decrease of 4.44 % to 54.5 % in MBC and 5.12 % to 35.7 % in BR values when compared to the uncontaminated soil, suggesting that the size and activity of the soil microbial community were suppressed, with the extent of suppression varying depending on the type of plant residues and concentrations of ZnO-NPs applied. These findings strongly suggest that the soil microbial community was subjected to heightened toxicity stress caused by ZnO-NPs, particularly at higher concentrations. In conclusion, ZnO-NPs can drastically influence the microbial abundance, maintenance energy demand, and C mineralization process in plant residue-amended calcareous soils.

Effects of Soil Tillage on the Agronomic Performance of Maize-Soybean Intercropping in Dry Land North Lombok, Indonesia By IJISRT

If land processing techniques on dry land are not carried out correctly, it can cause soil erosion and poorer soil fertility. Therefore, one way that can be done to prevent the soil from becoming sour is through proper soil processing accompanied by the addition of bio- ameliorants to the soil. This research aims to determine the effect of soil tillage on the agronomic performance of corn and soybean intercropping on dry land in North Lombok, Indonesia. The research was conducted from May to July 2023 in Pemenang Barat Village, Pemenang District, and North Lombok Regency. The study used an experimental method in the field using a randomized block design by testing five tillage techniques, i.e., Oo: without tillage; O1: without tillage, only sprayed with pre-growth herbicides before planting; O2: minimum tillage is only hoeing; O3: simple tillage and leveling; and O4: intensive tillage by hoeing, loosening, and leveling. The results showed that treatment-intensive and complete processing can increase the growth performance and biomass yield of maize and soybean intercropping. Treatment-intensive and complete processing can improve the performance of intercropping maize and soybeans in the dry land of North Lombok. To improve the agronomic performance of maize-soybean intercropping in the dry land of North Lombok, the best results are obtained using intensive and complete processing accompanied by the addition of bio-ameliorant at a dose of 15 tons per ha.