Inorganic Soil Research Articles

Tree Root-Associated Microbial Communities Depend on Various Floor Management Systems in an Intensive Apple (Malus × domestica Borkh.) Orchard.

Regenerative 3agriculture prioritizes soil health to build up organic soil carbon and nitrogen stocks while supporting the active and diverse soil biota that is a prerequisite for maintaining crop productivity and quality in sustainable food production. This study aimed at unravelling the impact of organic and inorganic soil maintenance systems in a 'Red Jonaprince' apple (Malus × domestica Borkh.) orchard on soil microbiota biodiversity and soil physico-chemical properties. During our study, we compared seven floor management systems in terms of microbial community diversity. Fungal and bacterial communities on all taxonomic levels differed largely between systems that augmented organic matter (organic) and other tested inorganic regimes. The dominant phylum of the soil in all management systems was Ascomycota. The operational taxonomic units (OTUs) within the Ascomycota were largely identified as members of Sordariomycetes, followed by Agaricomycetes, and both dominated in organic systems versus inorganic. The most prominent phyla, Proteobacteria, accounted for 43% of all assigned bacteria OTUs. Gammaproteobacteria, Bacteroidia, and Alphaproteobacteria were predominant in organic samples, while Acidobacteriae, Verrucomicrobiae, and Gemmatimonadetes were more abundant in inorganic mulches.

Kinetics and Adsorption Isotherm of Strontium on Sugarcane Biochar and Its Application in Polluted Soil

Removal of inorganic soil pollutants (e.g. Sr2+) is considered necessary requirement to protect the environment and public health. So sugarcane bagasse biochar (SCBB) was examined as a biosorbent material for Sr2+. This was done through adsorption Stirred-batch technique including a kinetic experiment, at two concentrations (50 and 150 mg/l) and an adsorption isotherm experiment at five concentrations (20, 50, 100, 150, and 200 mg/l), by using SrCl2·6H2O. Moreover, an examination of the role of SCBB at three dosages (0.5, 1, 2%w/w) in reducing the bioavailability of strontium in polluted soil through pots experiment by using Raphanus sativus. Kinetic data revealed that equilibration time was 3 h and pseudo-second-order model was more represented in data at low and high concentrations where (R2 = 0.999 and R2 = 1), respectively. Thus, chemisorption governed the adsorption process for Sr2+removal by SCBB. Furthermore, Langmuir isotherm model (R2 = 0.99) described the adsorption data better, which indicated that a monolayer type of adsorption plays a vital role in the removal of Sr2+ by SCBB. Pots experiment revealed that SCBB could significantly reduce Sr2+ uptake by Raphanus sativus. The percentages of decrease in the shoot were 5.82, 18.17, and 26.80% for SCBB dosage 0.5, 1 and 2% w/w, respectively. The percentages of decrease in root were 17.20, 36.89, and 53.34% for SCBB dosage 0.5, 1 and 2% w/w, respectively. Specific surface area and surface functional groups of sugarcane bagasse play a vital role in the retention of strontium. Hence, biochar played an important role in the removal of Sr2+ from aqueous solution and reduced its uptake by plants in soil.

Measuring integrated smallholder soil fertility management practices in Megech watershed, Tana sub-basin, Ethiopia

Nowadays, a combination of natural and man-made factors has led to a decline in the physical and chemical quality of the soil. In Ethiopia, declining soil fertility and quality that lead to low agricultural production are made worse by soil erosion and nutrient depletion. Adoption and implementation of integrated soil fertility management strategies have emerged as inevitabilities in terms of development in Ethiopia generally and in the Tana sub-basin of northwest Ethiopia specifically. This study was created to evaluate the Megech watershed's integrated smallholder soil fertility management methods' adoption factors, status, and scope. A total of 380 individual farmers were surveyed using a semi-structured questionnaire to gather primary data. Descriptive statistics and econometric estimating methods were combined in the study. The findings supported the use of inorganic fertilizer, tree planting, organic fertilizer, stone bunds, and soil bunds by households as the primary methods for managing soil fertility. The outcomes of the econometric model also show that households' adoption decisions for integrated soil fertility management practices are highly interdependent. Additionally, there were similar underlying factors that affected the status and intensity of implementing integrated soil fertility management practices. The research concluded that effective soil management policies and programs should be designed, and implemented by smallholder farmers, agricultural experts, research centers, and governmental and non-governmental organizations to improve the quality of soil for sustainable food production. Moreover, raising the affordability of financial services and strengthening smallholder farmers' access to education help to increase their income, which in turn encourages the use of integrated soil fertility management practices.

Assessment of soil chemical properties and pod yield of okra (Abelmoschus esculentus) as influenced by farm yard manure and urea in Southern Guinea Savannah agro-ecology of Nigeria

Plant and animal debris are fast becoming an environmental hazard in many urban, semi-urban and rural settlements in most parts of the tropics. This is due to the poor management of this debris in the environment. Plant and animal remains if properly managed will be a rich farm resource. Therefore, a field trial was conducted in Makurdi in the 2021 cropping season to study the effects of farm yard manure (FYM) and urea fertilizer on selected chemical properties of soil and yield of okra. The experiment consisted of nine treatments; control, 2.0 t/ha FYM, 3.5 t/ha FYM, 5.0 t/ha FYM, 15 kgN/ha, 30 kgN/ha, 2.0 t/ha FYM + 15 kgN/ha, 3.5 t/ha FYM + 15 kgN/ha, and 5.0 t/ha FYM + 15 kgN/ha. The design of the experiment was a randomized complete block design in three replications. The results show that the sole application of inorganic fertilizer lowered soil pH and organic matter content. Manure application either as sole (i.e 2.0 t/ha or 3.5 t/ha or 5.0 t/ha) or mixed with inorganic fertilizer (i.e 2.0 t/ha FYM +15kgN/ha, or 3.5t/ha FYM+15kgN/ha, or 5.0 t/ha FYM+15kgN/ha), increased soil pH and concentrations of nutrient elements in the soil. Similarly, pod yield was significantly affected by manure and inorganic fertilizer; the highest number of pods yield and weight (12 and 613 kg/ha respectively) were obtained from 30 kg N/ha. This was followed by yield obtained from manure plus NPK (611kg/ha) at 5.0 t/ha FYM + 15 kgN/ha. Notwithstanding pod yield obtained at 30 kgN/ha, the study reveals that combined use of farm yard manure and urea fertilizer improves the concentration of nutrients in the soil and enhances yield of okra in the study area.

Data fusion of XRF and vis-NIR using p-ComDim to predict some fertility attributes in tropical soils derived from basalt

X-ray fluorescence (XRF) and visible and near-infrared (vis-NIR) spectroscopies have been capable of predicting soil properties. Both techniques enable environmentally friendly soil analysis with minimal or no sample preparation, providing information about inorganic and organic-mineral soil components. Recent studies have demonstrated that XRF and vis-NIR data fusion may improve the quality of predictive models for soil attributes. Although promising results have been related to the vis-NIR and XRF data fusion for soil analysis, no approach has been consistently optimal. In some cases, the data fusion worsened the models' performance compared with individual models. Moreover, most of these studies are focused on model performance. Few studies assess the synergism among different techniques and how their complementarities/differences may improve the knowledge about the sample spectral responses. For this purpose, this study aimed to assess p-ComDim analysis as a mid-level data fusion approach for soil fertility prediction using vis-NIR and XRF data. Complementarily, p-ComDim results were compared with vis-NIR and XRF individual models and low- and high-level data fusion approaches. Soil organic carbon (SOC), exchangeable calcium (Ca2+) and magnesium (Mg2+), pH, the sum of base (SB), and cation exchange capacity (CEC) were considered representative variables of the soil chemical fertility. A relative improvement ranging from 5% to 33% was observed comparing p-ComDim with vis-NIR and XRF individual models. Moreover, p-ComDim results were better when compared with the two data fusion approaches most used in literature for soil fertility prediction (low- and high-level data fusion). In addition, the p-ComDim analysis allowed extracting the weights (saliences) of each technique as well as the synergism among their variables to predict each attribute, demonstrating that the most important common dimensions (CDs) to the predictive models in all analyzed attributes were those with higher silences in the XRF block. It shows the synergism among different spectral ranges and the potential of p-ComDim for vis-NIR and XRF data fusion in soil fertility prediction. Therefore, the results from the present study may contribute to a better understanding between soil sample constituents and spectral responses, assisting in the explainability of the multivariate regression models.

Phosphate Solubilization and Plant Growth Promotion by Pantoea brenneri Soil Isolates.

Phosphate solubilizing microorganisms (PSMs) in soil have been shown to reduce mineral phosphate fertilizer supplementation and promote plant growth. Nevertheless, only several P-solubilizing microorganisms capable of solubilizing both organic and mineral sources of soil phosphorus have been identified up to now. The aim of this study was to evaluate the inorganic soil phosphate solubilizing activity of phytate-hydrolyzing Pantoea brenneri soil isolates. We showed that the strains efficiently solubilize a variety of inorganic phosphates. We optimized the media composition and culturing conditions to improve the solubilization efficiency of the strains and investigated the mechanisms of their phosphate solubilization. Through HPLC analysis, it was determined that P. brenneri produce oxalic, malic, formic, malonic, lactic, maleic, acetic, and citric acids as well as acid and alkaline phosphatases while growing on insoluble phosphate sources. Finally, we analyzed the influence of P. brenneri strains with multiple PGP-treats on plant growth in greenhouse experiments and showed their ability to promote growth of potato.

Response of soil microbial Communities, inorganic and organic soil carbon pools in arid saline soils to alternative land use practices

Soil organic and inorganic carbon (SOC & SIC) and microbial community structure are key indicators of soil quality and productivity in arid-saline soils. Salinity stress and diminishing availability of freshwater (FW) for irrigation are major constraints for productivity and improving soil quality indicators. Using treated wastewater (TW) and implementing climate-smart cropping systems are promising alternatives to replace freshwater usage in intensive cropping systems, however, impacts on the microbial community and net-carbon sequestration potential are not clearly understood. This field study was conducted in an arid saline-soil to investigate soil microbial community structure and soil carbon contents under a combination of treatments comparing bioenergy sorghum (So) and switchgrass (Sg), two irrigation water sources (FW & TW), and gypsum amendment (GA), to a native-soil control. After three years of implementing these treatments, soil samples were collected and analyzed for total carbon (TC), SOC, SIC, microbial biomass-carbon (MBC) and microbial community structure. Results showed that TW increased microbial diversity and shifted the community structure towards copiotroph-dominated prokaryotes. Several predominant and responsive taxa were associated with divergent trends of SOC, SIC and salinity parameters. Both SOC and SIC pools were sensitive to treatments and demonstrated divergent trends, as contents of TC and SOC were higher in TW-treatments, but of SIC were significantly lower in several So_TW treatments. Treatment TW_So_GA assembled a distinctive microbial community structure, accumulated the highest content of SOC (7.66 g kg−1) but recorded the lowest content of SIC (6.63 g kg−1). The lowest content of SOC was observed in native soil (4.58 g kg−1) but contained the highest SIC (8.15 g kg−1). The study results revealed the agronomic systems with higher potential for increasing TC and SOC content in arid-saline soils. Surface soil SIC was responsive to agronomic management, and several treatments produced disparate impacts on SOC and SIC stocks, which warrant for considering TC as the key indicator for assessing carbon sequestration in arid lands.

Consistent microbial and nutrient resource island patterns during monsoon rain in a Chihuahuan Desert bajada shrubland

AbstractIn dryland soils, spatiotemporal variation in surface soils (0–10 cm) plays an important role in the function of the “critical zone” that extends from canopy to groundwater. Understanding connections between soil microbes and biogeochemical cycling in surface soils requires repeated multivariate measurements of nutrients, microbial abundance, and microbial function. We examined these processes in resource islands and interspaces over a two‐month period at a Chihuahuan Desert bajada shrubland site. We collected soil in Prosopis glandulosa (honey mesquite), Larrea tridentata (creosote bush), and unvegetated (interspace) areas to measure soil nutrient concentrations, microbial biomass, and potential soil enzyme activity. We monitored the dynamics of these belowground processes as soil conditions dried and then rewetted due to rainfall. Most measured variables, including inorganic nutrients, microbial biomass, and soil enzyme activities, were greater under shrubs during both wet and dry periods, with the highest magnitudes under mesquite followed by creosote bush and then interspace. One exception was nitrate, which was highly variable and did not show resource island patterns. Temporally, rainfall pulses were associated with substantial changes in soil nutrient concentrations, though resource island patterns remained consistent during all phases of the soil moisture pulse. Microbial biomass was more consistent than nutrients, decreasing only when soils were driest. Potential enzyme activities were even more consistent and did not decline in dry periods, potentially helping to stimulate observed pulses in CO2 efflux following rain events observed at a co‐located eddy flux tower. These results indicate a critical zone with organic matter cycling patterns consistently elevated in shrub resource islands (which varied by shrub species), high decomposition potential that limits soil organic matter accumulation across the landscape, and nitrate fluxes that are decoupled from the organic matter pathways.

Influence of INM on Performance of Soybean-Wheat based Cropping System under Central Narmada Agro-Climatic Zone of Madhya Pradesh

A field experiment was conducted to evaluate organic vis-à-vis inorganic fertilizers and soil sustainability in soybean-wheat cropping sequence for two consecutive years. Grain yield of both the crops, i.e., soybean (16.29 q/ha) and wheat (46.05 q/ha) was observed to be significantly superior by fertilizer application as per general recommended dose of respective crops. Integrated application of fertilizers i.e., inorganic fertilizers 50% and organic fertilizers 50% was found to be the next superior treatment to that of general recommended dose. Soil properties were improved by use of organic and inorganic fertilizers in combination. However, no significant change was observed in case of soil pH and electrical conductivity.

Isolation of Phosphate-Solubilizing Microorganisms and the Formulation of Biofertilizer for Sustainable Processing of Phosphate Rock.

As phosphorus (P) bioavailability is limited in arable lands, chemical fertilizers are being used by farmers to increase crop production. Phosphate-solubilizing microorganisms (PSMs) increase the bioavailability of sparingly soluble inorganic and organic soil phosphorus. Therefore, the current study was an effort to evaluate the phosphate-solubilizing efficiency of PSMs using tricalcium phosphate (TCP) and Eppawala rock phosphate (ERP). The efficiency of phosphate solubilization by a series of identified isolates was compared using TCP (5 g L-1) and ERP (5 g L-1) as a P source in Pikovskava's broth. Twelve microbial isolates that showed a higher efficiency in phosphate solubilization were selected for the production of the biofertilizer. The isolate F10 in ERP broth was characterized by the highest significant level of available phosphorus (896.98 ± 10.41) mg L-1, followed by F5 (Aspergillus sp.) in TCP broth 991.43 ± 1.37 mg L-1. A pot trial was carried out by using Capsicum annuum L. as the test plant in two soil conditions: sterilized soil and non-sterilized soil with six treatments and four replicates. The significantly highest plant height, leaf length, and width were shown by chili plants treated with the formulated biofertilizer. Therefore, the application of native PSMs appeared to be an efficient method of solubilizing sparingly soluble P compounds into plant-available forms.

Role of different organic and inorganic amendments in the biofortification of iodine in Coriandrum sativum crop

Iodine deficiency disorder (IDDs) is one of the most prevailing and common health issues in mountainous communities. An effective way to control the prevalence and emergence of IDDs in remote areas is to use iodized salt. However, recent studies indicated that iodized salt is mostly lost during the cooking process. The current study of iodine biofortification differed from the previous studies in two main aspects: it involved exogenous organic iodine (OI), and inorganic iodine such as potassium iodide (KI), added in the amended soils, which previous studies did not consider. Moreover, the translocation, transformation, and distribution of iodine from soil to plants are poorly understood in amended soil. Thus, identifying an effective management option to enhance iodine (I) bioavailability in nutrient-deficient soils is currently a significant challenge. Therefore, a greenhouse study was conducted to investigate the effects of organic and inorganic soil amendments on the uptake of different iodine sources in coriander crops. Results showed that applying an inorganic iodine source significantly enhanced the iodine edible part of the crop compared to the control (p < 0.05). The application of soil amendments relatively improved iodine uptake by the coriander crop compared to the control. The highest iodine was found in crop tissues grown in wood ash-amended soil supplemented with KI (291.97 μg kg−1). The KI uptake was significantly higher than the OI (p < 0.05). Compared to OI, a higher translocation factor (0.96) and distribution coefficient (3.51) were found for plants treated with KI. Thus, this study indicates that a suitable soil amendment can be a better option for iodine biofortification and that it can serve as an alternative to iodized salt in preventing IDDs.

Experimental community coalescence sheds light on microbial interactions in soil and restores impaired functions

BackgroundMicrobes typically live in communities where individuals can interact with each other in numerous ways. However, knowledge on the importance of these interactions is limited and derives mainly from studies using a limited number of species grown in coculture. Here, we manipulated soil microbial communities to assess the contribution of interactions between microorganisms for assembly of the soil microbiome.ResultsBy combining experimental removal (taxa depletion in the community) and coalescence (mixing of manipulated and control communities) approaches, we demonstrated that interactions between microorganisms can play a key role in determining their fitness during soil recolonization. The coalescence approach not only revealed the importance of density-dependent interactions in microbial community assembly but also allowed to restore partly or fully community diversity and soil functions. Microbial community manipulation resulted in shifts in both inorganic nitrogen pools and soil pH, which were related to the proportion of ammonia-oxidizing bacteria.ConclusionsOur work provides new insights into the understanding of the importance of microbial interactions in soil. Our top-down approach combining removal and coalescence manipulation also allowed linking community structure and ecosystem functions. Furthermore, these results highlight the potential of manipulating microbial communities for the restoration of soil ecosystems.1hnKtMhPkxX_a_nwXw9y6KVideo

Potential of Eight Species of Legumes for Heavy Fuel Oil-Contaminated Soil Phytoremediation

The soil contamination of petroleum hydrocarbons is a widespread problem requiring an environmentally friendly and cost-effective solution. This study aimed to test the leguminous plant resistance to heavy fuel oil (HF) soil contamination and to evaluate their phytoremediation efficiency and potential to maintain the soil nutrient content. Eight legume species were selected for the study. The selected legumes were grown in a growth chamber in HF-contaminated soil (2.5 and 4 g kg−1) for 90 days. After the soil treatment, the changes in the soil HF contamination, nutrient concentrations, and plants morphology were monitored. The HF pollution significantly affected the dry weight of the shoots and roots of seven of the eight tested plant species. M. sativa, M. albus, and L. corniculatus had the highest phytoremediation potential with the efficiency of the HF removal up to 95 %. The leguminous plant-assisted HF remediation resulted in an increase in the ammonium and inorganic phosphorous soil content, with the highest increase in the case of L. corniculatus and O. viciifolia. The cultivation of Phaseolus vulgaris, L. corniculatus, and M. albus helped to maintain the soil nitrates close to the constant level. The study demonstrated that M. sativa, L. corniculatus, and M. albus were the most efficient in HF removal.

A face oculta das cenas de crime: uma revisão sobre microvestígios

Introduction: Microtrace consists of materials of different nature that can be found in crime scenes, being difficult to see with the naked eye, due to their submillimetre, submicroscopic or microscopic dimensions. Objectives: This work aimed to address the characteristics of the main types of microtrace found in crime scenes. Material and Methods: As a research methodology, publications exclusively in the format of scientific articles were sought, indexed in the Web of Science and ScienceDirect databases, using the terms microtrace and trace evidence. Results: Microtrace are classified according to their organic origin (fingerprints, diesel and biodiesel, hair, wood, microscopic plant origin and natural fibres), natural inorganic (microfossils, minerals and soils) and anthropic inorganic (bricks, paints, glass, plastics, synthetic fibres, gunshot residue and paper), and can reveal crucial information at crime scenes, depending on the technique used to process it (e.g., inductively coupled plasma, infrared spectroscopy, gas and liquid chromatography, micro Raman spectroscopy). In this way, laboratories must meet specific requirements, regardless of the analytical technique to be used, to extract reliable information from microtrace. These requirements consist of: 1) Accuracy, 2) Sensitivity, 3) Uniqueness, 4) Association, 5) Speed and simplicity, 6) Versatility, 7) Reliability and reproducibility, 8) Traceability, 9) Accessibility, and 10) Availability of data. Conclusions: This work highlighted the diversity and importance of microtrace, since extracting information from them can give them great potential as material evidence in criminal investigations, depending on the applied collection methods and the techniques used in their laboratory examination.

Aluminum speciation in forest soils and forest floor density fractions using synchrotron-based XANES spectroscopy

The speciation of aluminum (Al) in soils is important for Al cycling and Al toxicity in terrestrial ecosystems. Current soil Al speciation methods are mostly wet-chemical, discriminating among operationally defined fractions rather than distinct Al species. We performed synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy at the Al K-edge (1560 eV) for Al speciation in different horizons of three forest soil profiles and O layer density fractions. We deconvoluted the spectra by linear combination fitting (LCF; 1550–1690 eV), using reference spectra of 22 diluted inorganic and organic Al-bearing soil constituents. Our first time application of Al XANES spectroscopy + LCF for soil Al speciation revealed methodological challenges and difficulties. Thus, a minimum sample Al content of 5 mg g−1 was necessary to yield spectra with satisfactory signal-to-noise ratio in reasonable acquisition time, and Al contents > 15 mg g−1 resulted in spectrum distortion by self absorption, requiring adequate sample dilution prior to XANES analysis. Nevertheless, Al K-edge XANES spectroscopy allowed for estimating the relative contribution of different Al species to total Al in our soil and density fraction samples. The Al XANES spectra of different Al carboxylates were very similar. The same was true for different Al phenol species, different 2:1 clay minerals (illite, montmorillonite, chlorite), different 1:1 clay minerals (kaolinite, halloysite), and different feldspars (orthoclase, anorthite), jeopardizing a reliable differentiation and quantification of these specific compounds. We therefore combined these compounds into the groups SOM carboxyl(ate)-bound Al, SOM phenol-bound Al, 1:1 clay mineral-bound Al, 2:1 clay mineral-bound Al, and feldspar-bound Al. XANES results showed a decreasing contribution of organically bound Al to total soil Al with soil depth (O layers 20–43 %; Ah horizons 10–22 %; B horizons 0–12 %). Major inorganic Al-bearing constituents in the fine earth of all soils were 2:1 clay minerals and feldspars, followed by 1:1 clay minerals (kaolinite), and Fe oxyhydroxides with partial Al substitution. Gibbsite or allophane did contribute only marginally to fine-earth Al in our soils. Different Oa layer density fractions with different SOM content and SOM decomposition status also differed in Al content and Al speciation, indicating the existence of spatially separated forest floor constituents with different Al speciation. Aluminum in the mineral-dominated density fraction > 1.6 g cm−3 with advanced SOM decomposition, comprising about 50 % of total Oa mass, was entirely bound in clay minerals (65–70 % of total Al) and feldspars (30–35 % of total Al). In contrast, Al in the mineral-poor density fraction < 1.0 g cm−3 was entirely bound to SOM as Al-organo complex, with Al bound to SOM phenol groups (>75 % of total Al) being more relevant than Al bound to SOM carboxyl(ate) groups. However, the latter density fraction comprised only 4 % of total Oa mass in both soils. Aluminum K-edge XANES spectroscopy, particularly when combined with total element analysis and XRD, is a promising novel tool for speciation of Al in soils and in SOM-mineral associations, with a great potential to promote our understanding of Al biogeochemistry in terrestrial ecosystems.

Controls on organic and inorganic soil carbon in poorly drained agricultural soils with subsurface drainage

Controls on organic and inorganic soil carbon in poorly drained agricultural soils with subsurface drainage

Responses of Fine Root Traits and Soil Nitrogen to Fertilization Methods and Nitrogen Application Amounts in a Poplar Plantation

Inappropriate fertilization management practices have led to low timber production in intensive plantation systems in China. Thus, optimized conventional or advanced fertilization management practices are needed. We aimed to quantify whether optimized furrow fertilization (FF) is comparable to advanced drip fertigation (DF) and to make recommendations regarding fertilization management strategies for poplar plantations. A completely randomized block design experiment with two fertilization methods (DF and FF) and four N application amounts (F0: 0, F1: 68, F2: 113, and F3: 158 kg N·ha−1·yr−1) was carried out on a Populus × euramericana cv. ‘Guariento’ plantation. Fine root biomass density (FRBD), fine root length density (FRLD), specific root length (SRL), soil total nitrogen (STN), soil inorganic nitrogen (SIN), soil ammonium (NH4+-N) and nitrate nitrogen (NO3−-N) were measured. The productivity increment was calculated based on tree surveys. The results showed that FRBD and FRLD decreased with the soil depth, and more than 86% was distributed within the 40 cm soil depth. FRBD, FRLD, productivity increment and soil N increased with an increasing amount of N application. DF treatments achieved 117%, 94% and 10% higher FRBD, FRLD and productivity increments, respectively, than did FF treatments. The averages of STN, SIN, NH4+-N and NO3−-N under FF were higher than those under DF, leading to higher concentrations of residual NO3−-N in deep soil. Beneficial management practices for fine root growth were evaluated in the following order: water coupled with N &gt; only N ≥ only water &gt; control. FRBD was positively correlated with the productivity increment. Therefore, fine root extension to increase soil resource absorption yields greater productivity under DF treatments. Drip fertilization is recommended as a better fertilization method to greatly promote the growth of fine roots, as well as productivity and residual lower soil N for poplar plantations.

Biomass ash-based soil improvers: Impact of formulation and stabilization conditions on materials’ properties

Biomass ash and sludge from pulp and paper industry have enormous potential to be recycled and used as components in soil improvers. Those materials can supply large amounts of nutrients and organic matter and its recycling avoids the need of landfilling. However, these wastes cannot be directly applied to soils. Some form of processing is required to ensure efficient soil pH correction, fertilization, guarantee soil protection, and reduce potential sanitary and environmental risks.In this study, different ash formulations (with or without addition of organic wastes) and stabilization conditions (indoors vs. outdoors) were tested to optimize physico-chemical properties of ash-based granules to be used as soil improvers. Biomass fly ash (BFA) was granulated in combination with different binding agents: distilled water, biological sludge (BS), biological sludge effluent (BSE), or composted biological sludge (CBS). All granulated materials were alkaline, ranging from pH 7.9 to 12.1. Their acid-neutralizing capacity ranged from 45 to 51 equiv. CaCO3, rendering them suitable as liming materials. Incorporation of organic materials (BS and CBS) enhanced water holding capacity (up to 38 %) and bulk porosity (up to 20 %). Stabilization outdoors resulted in a faster carbonation and consequent reduction of the granules pH. It also yielded a lower electrical conductivity and lower soluble salts content (Ca, Cl, K, and Na) than materials stabilized indoors. After processing and stabilization, some of these ash formulations fulfilled the criteria to be used as component for inorganic macronutrient fertilizers, liming materials or inorganic soil improvers under the EU Fertilizing Products Regulation.

LDPE and biodegradable PLA-PBAT plastics differentially affect plant-soil nitrogen partitioning and dynamics in a Hordeum vulgare mesocosm

Micro and macroplastics are emerging contaminants in agricultural settings, yet their impact on nitrogen (N) cycling and partitioning in plant-soil-microbial systems is poorly understood. In this mesocosm-scale study, spring barley (Hordeum vulgare L.) was exposed to macro or microplastic produced from low density polyethylene (LDPE) or biodegradable plastic at concentrations equivalent to 1, 10 and 20 years of plastic mulch film use. Partitioning of 15N-labelled fertiliser into plant biomass, soil and leachate yielded a partial mass balance. Soil N partitioning was probed via compound-specific 15N-stable isotope analyses of soil microbial protein. Concentration-dependent decreases in plant 15N uptake occurred with increased leached nitrogen for LDPE microplastic. Assimilation into soil microbial protein was higher for biodegradable plastics, which we associate with early-stage biodegradable plastic degradation. Partitioning of 15N into inorganic soil N pools was affected by LDPE size, with lower assimilation into the microbial protein pool. While microplastics and macroplastics altered soil N cycling, the limited impacts on plant health indicated the threshold for negative effects was not reached at agriculturally relevant concentrations. This study highlights the difference between conventional and biodegradable plastics, and emphasises that the interplay of micro and macroplastics on soil N cycling must be considered in future studies.

Economics and fertility status of organic and inorganic fertilizer-applied soil in sweet corn (Zea mays) cultivation

A rainfed field experiment was laid out during the rainy season of 2019 at the Research farm of Raj Mohini Devi College of Agriculture and Research Station, Ambikapur, Chhattisgarh, to study the effect of integrated nutrient management on economic viability and residual nutrient status of soil in sweet corn (Zea mays L. saccharata). The experiment comprised 2 sources of organic manures, viz. vermicompost and FYM together with no organic manure and 3 levels of fertilizers, viz. 50%, 75% and 100% recommended dose of fertilizer (RDF) (120, 60 &amp; 40 kg N, P and K/ha respectively) and replicated trice. The result showed that, the application of 3 t vermicompost/ha resulted in the highest growth and yield attributes as well as cob and fodder yields, followed by 5 t FYM/ha and both these treatments proved significantly superior to no organic manure. However, 100% RDF recorded higher value of these parameters and was found significantly superior to 75% and 50% RDF. The highest dehusked cob yield (14.9 t/ha) and net returns (` 147,265.2/ha) were obtained with 3.0 t vermicompost/ha + 100% RDF. Different organic sources did not cause any significant effect on available N, P and K but significantly enhanced organic carbon content of the soil. Nutrient levels had significant effect on available N, P and K of the soil at harvesting.