Media Amendments Research Articles

Suitability of Phytoremediation Processes for Indoor Air and Practical Applications

Background: It is more challenging than designing buildings, people have difficulty improving indoor air quality (IAQ) affordably in existing buildings with limited area. This paper presents indoor phytoremediation solutions-based quotations, which are affordable to the public, besides being able to work to remediate air simultaneously. Methods: Literature sources are primarily Mendeley reference managers and expanded from open-access reputable journals worldwide. The indoor phytoremediation solution was obtained from an up-to-date literature review covering processes of all plants and related sections. Results: The study identified three categories of indoor phytoremediation: plant-related bioremediation, rhizosphere bioremediation, and plant processes. To improve indoor air quality, plant-related bioremediation is a suitable process to escalate while still paying attention to ameliorating the plant processes and inhibiting bioaerosols. For practical applications, narrow-leaved plant species can enhance phylloremediation, growth media amendments to enhance rhizosphere bioremediation, and support separating biodegradable waste. Placing one decorative plant anywhere indefinitely improves the IAQ for buildings with a limited area because plants are essential biota of a living ecosystem. Conclusion: Based on the suitability of the process for indoor air pollutants, the main contribution of plants to remediate indoor air is plant-related bioremediation, followed by plant processes, and rhizosphere bioremediation

Solid humic substance enhanced spinach abiotic stress tolerance under combined drought, salinity, and daily heat stress

Spinach is a crop of economic importance in the Wintergarden region of Texas, where increasing soil salinity, irrigation water restrictions, and heat stress challenge its production. Improving abiotic stress tolerance and resource use efficiency are important goals for sustainable agricultural production. Although the effect of humic substances (HS) on abiotic stress tolerance in spinach has been evaluated under single stress, such as heat, drought, or salinity, their impact under combined abiotic stresses is unknown. We hypothesized that solid humic substances would be effective in alleviating multifactorial abiotic stress in spinach, which we examined in our first experiment, and further hypothesized that salinity stress in spinach would occur after a threshold intensity but that humic substance applications would ameliorate stress intensity past this threshold, which we examined in our second experiment. Three-week-old spinach seedlings (Spinacia oleracea L. cv. ‘Seaside’) were grown using an automatic gravimetric watering system in a climate-controlled high tunnel where daily maximum temperatures exceeded 32 °C. In a factorial experiment, we applied HS (control and 1 % v/v HS media amendment), drought (100 % and 50 % field capacity), and salinity (25 mL of RO water or 100 mM NaCl every other day) treatments. HS and HS×Salinity treatments more than doubled shoot and root FW and DW, leaf area, root length, and root surface area compared to other stresses, indicating HS improved growth and stress tolerance. Improved growth was matched with improved resource use efficiency, as HS and HS×Salinity treated plants exhibited the greatest WUE. Drought stress also increased WUE relative to the control but lowered transpiration rate responses to VPD in contrasts to HS and HS×Salinity treated plants, which increased their transpiration rates in response to increasing VPD. Salinity treatments increased sodium content (Na+) in both shoots and roots. No HS effect was observed in shoot Na+ accumulation, but HS reduced Na+ in roots under the Drought×Salinity treatment. Strong interactions between drought and salinity were observed for shoot and root Na+, Na+/K+, and shoot K+, showing that spinach accumulates Na+ and reduces K+ when drought and salinity stress are combined. HS had no apparent effect on leaf metabolites. Drought and salinity differentially impacted MDA, proline, and antioxidant content and activities, while HS showed no effect. Drought stress significantly increased MDA and proline while reducing TPC, TFC, ABTS, and FRAP. Salinity stress significantly decreased MDA, TPC, ABTS, FICA, and FRAP. In conclusion, HS improved overall spinach growth and WUE while decreasing root Na accumulation, and subsequently enhancing spinach stress tolerance.

A Microalgae Photobioreactor System for Indoor Air Remediation: Empirical Examination of the CO2 Absorption Performance of Spirulina maxima in a NaHCO3-Reduced Medium

Microalgae-based photobioreactors (PBRs) have gained attention as a sustainable solution for indoor air quality (IAQ) control. This study investigates indoor CO2 absorption performance of Spirulina maxima (S. maxima) in NaHCO3-limited cultivation (standard: NaHCO3-free medium = 1:1 v/v%) of a lab-scale PBR system. Cultivation performance of three medium amendments (standard, 50% NaHCO3, and NaHCO3-free) was compared by observing cell growth for 30 days in a controlled environment. Empirical examinations were conducted to evaluate the algal CO2 uptake, and overall system performance in the culture volumes of 2, 4, and 7 L and natural indoor CO2 concentration of ~1100 ppm. We found CO2 was reduced by ~55%, in an air chamber of 0.064 m3, showing the greatest mitigation rate (~20%) on Day 4. Under a high concentration of CO2 (10,000 ppm), the CO2 levels were decreased up to ~90% before saturation. This research provides valuable insights into the development of S. maxima-activated IAQ control systems for airtight buildings.

Life Cycle Assessment of Bioretention Cell Designs and Evaluation of Environmental Impact of Media Amendments for Catalysis in Urban Flood Mitigation

Life Cycle Assessment of Bioretention Cell Designs and Evaluation of Environmental Impact of Media Amendments for Catalysis in Urban Flood Mitigation

Biochar functionalized with layered double hydroxides improve physicochemical properties of growing media

Despite their extensive use in wastewater treatment, biochar/layered double hydroxides (BC/LDHs) may serve as novel growing media (GM) amendments for horticultural farming. In the present study, GM was supplemented with BC/LDHs at three application rates [0%, 2.5%, and 5.0% (wt/wt)] denoted as BC/LDHs0, BC/LDHs2.5, and BC/LDHs5.0, respectively, and successive changes in the physiochemical properties of GM were evaluated. The experimental results indicated that at the end of the incubation period, GM was vastly stimulated after BC/LDH amendments, particularly in the case of BC/LDHs5.0, where the pH (7.05) and electrical conductivity (0.43 dS/m) were in accordance with the optimal criteria for soilless cultivation. Moisture content, bulk density, total porosity, and water retention were also improved after BC/LDH remediation although there were insignificant differences among individual dosages for the last two indices. Although increased amendment levels did not benefit total carbon and nitrogen, the maximum efficiency that was reflected in an enhancement of at least 86% in phosphorus, magnesium, and aluminum contents was derived from BC/LDHs5.0. Nevertheless, due to an overriding concern over aluminum interference, BC/LDHs2.5 was recommended given its non-significant difference with non-amendment. Such positive effects of BC/LDHs, on a wide range of GM quality indicators, signify their potential in amendment applications. This study not only provides an alternative approach for the reuse of plant-essential nutrients, but also a means to facilitate sustainable adsorbent waste management, through the extended applicability and validity of BC/LDHs and their utilization in agricultural systems.

Assessment of Fresh Miscanthus Straw as Growing Media Amendment in Nursery Production of Sedum spectabile 'Stardust' and Hydrangea arborescens 'Annabelle'.

The aim of this research was to assess the influence of fresh miscanthus straw shreds as a component of growing media in nursery production of perennial Sedum spectabile 'Stardust' and woody shrub Hydrangea arborescens 'Annabelle'. A total of five substrate mixes composed of peatmoss and miscanthus straw were used: 100%P, 70%P:30%M, 50%P:50%M, 70%P:30%M, 100%M. Each substrate was subjected to three fertilizer treatments: Basacote, Basacote + YaraMila, and YaraMila. The growth response of both tested species was very similar. In general, plants performed best in 100%P, and the quality decreased with increasing miscanthus straw amendment; however, differences in height and dry weight at the level of ~9% suggest that Sedum plants obtained market value with up to 50% miscanthus amendment and Hydrangea plants with up to 30% miscanthus mixed in media. The most favorable effect on the tested parameters was a combination of Basacote + YaraMila, which delivered more soluble salts, and in higher rates than Basacote and YaraMila used separately. Decrease in EC and nutrients in the substrate with increase in miscanthus straw amendment suggest that uniform irrigation among all the treatments contributed to nutrients leaching from miscanthus media due to its lower water holding capacity.

Growth kinetics and purifying performance of A. Platensis in stirring-free culture based on brewery effluent's supernatant.

Due to costs of setting up and operating electrical stirring systems to keep algae in suspension andexposed to light,cultivation of monospecific algae is poorly expanded in developing countries. However, some algal species, such as Arthrospira platensis, are equipped with gaseous vesicles that allow them to stay afloat and increase their exposure to light. In this study, we investigated in an unstirred outdoor environment, its growth kinetic and purifying performance in abrewery effluent-based media. Batch cultures were carried out in three experimental treatments and evolution of physicochemical and growth parameters were monitored. Then its contribution to depollution was determined. Results show that optimal conditions for producing A. platensis include the culture tank transparency, the effluent dilution (i.e. 10%), and the culture media amendment with sodium bicarbonate and sodium nitrate. The average productivity recorded reached 0.55 g DW·L-1·d-1 during the exponential growth phase, while preserving culture from contamination. COD and total nitrogen concentrations were reduced to 32.5 and 64.91%. Such results open up prospects for low-cost production of certain algae, in transparent and relatively high barrels, thus breaking the classic barriers related to shallow basin depth and mechanical agitation traditionally considered as critical to the success of algal production.

Biochars as culture medium additives influence organogenic potential of plant explants through changes in endogenous phytohormone and carbohydrate contents in Daphne species

Biochar applicability as culture medium amendment is rarely investigated due to its uncovered impact on in vitro cultured plants. This study assessed the feasibility of several biochars as alternatives to activated charcoal, for micropropagation of two ornamental Daphne species (Thymelaeaceae). We distinguished metabolic responses that were specific for: a) medium supplementation with any type of charcoal; b) biochar addition; c) biochar activation; d) the process of charcoal activation itself. We compared impacts of industrially produced biochar and three different biochars made in small-scale stoves (from residues of Gliricidia sepium) on organogenic capacity and physiological status in Daphne sp. shoots. Metabolite profiling revealed that biochars differently modulated accumulation of endogenous phytohormones and osmolytes in the shoots. Biochars reduced accumulation of proline, betaines and stress-related phytohormones (ABA, jasmonates), and impacted carbohydrate profile. For D. jasminea the most impactful was biochar activation, which increased micropropagation efficiency by elevating cytokinin and soluble sugars content. For D. tangutica charcoal/biochar activation, and application of biochar reduced accumulation of ABA and jasmonic acid, increased level of gibberellins, salicylic and benzoic acid, and altered carbohydrate composition. The study revealed that tested biochars can be used as a sustainable medium supplements without negative impact on production of new microshoots. Based on studied species we showed that biochar supplements could stimulate plantlet formation (D. jasminea,) ameliorate stress response (D. tangutica), and constitute a way of undesired biomass utilization (invasive species G. sepium).

Life Cycle Assessment (LCA) of Substrate Mixes Containing Port Sediments for Sustainable 'Verna' Lemon Production.

The increase in maritime trade and its global economic importance have forced port management actors to carry out the periodic dredging of their sediments to maintain an adequate depth for the passage of large ships to maintain their operation and competitiveness. During the dredging process, large volumes of port sediment are generated. Dredged port sediment is currently considered a waste material and its disposal is regulated. Finding ways to safely reuse port sediments is necessary for sustainable development. In this study, a life cycle assessment (LCA) methodology was applied to identify the environmental impact of port sediments when used as a culture medium for lemon trees. A total of 90 lemon trees (Citrus limon L. Burm var ‘Verna’) were used in the trial. The trees were grown under controlled conditions using three substrates, with different portions of peat and port sediment (25%, 50%, and 75%) to identify the real impacts of the culture media on the growth process. The LCA was calculated and analyzed according to the ISO 14040:2006 standard, using the SimaPro v. 9.3 software (PRé Sustainability B.V, Amersfoort, The Netherlands). The functional unit defined for the three-culture media was 1 kg of lemons. The LCA results showed a significant increase in the environmental impact of lemon cultivation proportional to port sediment content (75%), due to the decrease in fruit production caused by the sediment. However, the least impact was identified for the culture medium at 50% peat and 50% port sediment. The greatest impacts were more related to crop management rather than the port sediment content. The results showed that the use of the port sediment, mixed with other substrates as an agricultural medium amendment, is a viable option for lemon growers.

A long term study elucidates the relationship between media amendment and pollutant treatment in the stormwater bioretention system: Stability or efficiency?

Media amendment has been more and more frequently tested in stormwater bioretention systems for enhanced runoff pollutant treatment. However, few studies systematically evaluated the amended system over a long time span, which hindered the further optimization of the proposed amended media. In this study, biochar-pyrite system (PB), conventional sand system (SB), and biochar-woodchip system (WB) were established and operated for 26 months. Media amendment greatly enhanced the dissolved nutrient removal, the highest total dissolved nitrogen removal in PB and WB were 65.6±3.6% and 68.2±2.5%, respectively. Compared with PB, WB could maintain excellent nitrogen removal under long-term operation. In contrast, PB demonstrated stable and more effective total dissolved phosphorus removal during all stages (73.1±3.1%-80.3±4.1%). A high content of phosphorus and organic matter was leached in WB especially at initial operation, while the initial pollutant leaching in PB and SB is much lower, about one-third of WB. Microbial and metabolic function analysis indicated that the microbial community in the bioretention system is complicated and stable. Media amendment enhanced microbial diversity and the relative abundance of functional genera related to nitrogen (Nitrospira, Thauera, Denitratisoma, etc.), sulfur (Thiobacillus, Geobacter, Desulfovibrio, etc.), and carbon cycles (cellulomonas, saccharimonadales, and SBR1031, etc.), which well explained the enhanced pollutant removal and by-product leaching in different systems. Overall, the current study indicates that although media amendment is conducive to enhanced dissolved nutrient removal in bioretention systems, it can hardly maintain both stability and efficiency from initial set-up to long-term operation. In practical application, catchment characteristics, prioritized pollutants, meteorological factors, etc. should all be considered before choosing suitable amended media and its design factors, thereby maximising the stability and efficiency of the bioretention system.

The suitability of de-inked paper sludge as growing media amendment for ornamental potting plants

The suitability of de-inked paper sludge as growing media amendment for ornamental potting plants

Phosphorus removal, metals dynamics, and hydraulics in stormwater bioretention systems amended with drinking water treatment residuals.

Drinking water treatment residuals (DWTRs) are a promising media amendment for enhancing phosphorus (P) removal in bioretention systems, but substantial removal of dissolved P by DWTRs has not been demonstrated in field bioretention experiments. We investigated the capacity of a non-amended control media (Control) and a DWTR-amended treatment media (DWTR) to remove soluble reactive P (SRP), dissolved organic P (DOP), particulate P (PP), and total P (TP) from stormwater in a two-year roadside bioretention experiment. Significant reductions m SRP, PP and TP concentrations and loads were observed in both the Control and DWTR media. However, the P removal efficiency of the DWTR cells were greater than those of the Control cells for all P species, particularly during the second monitoring season as P sorption complexes likely began to saturate in the Control cells. The difference in P removal efficiency between the Control and DWTR cells was greatest during large storm events, which transported the majority of dissolved P loads in this study. We also investigated the potential for DWTRs to restrict water flow through bioretention media or leach heavy metals. The DWTRs used in this study did not affect the hydraulic performance of the bioretention cells and no significant evidence of heavy metal leaching was observed during the study period. Contrasting these results with past studies highlights the importance of media design in bioretention system performance and suggests that DWTRs can effectively capture and retain P without affecting system hydraulics if properly incorporated into bioretention media.

Accumulation of high-molecular-weight polycyclic aromatic hydrocarbon impacted the performance and microbial ecology of bioretention systems

Bioretention has been considered as an effective management practice for urban stormwater in the removal of pollutants including polycyclic aromatic hydrocarbons (PAHs). However, the accumulation of high-molecular-weight (HMW) PAHs in bioretention systems and their potential impact on the pollutants removal performance and microbial ecology are still not fully understood. In this study, comparisons of treatment effectiveness, enzyme activity and microbial community in bioretention systems with different types of media amendments were carried out at different spiking levels of pyrene (PYR). The results showed that the removal efficiencies of chemical oxygen demand (COD) and total nitrogen in the bioretention systems were negatively impacted by the PYR levels. The relative activities of soil dehydrogenase and urease were increasingly inhibited by the elevated PYR level, indicating the declining microbial activity regarding organic matter decomposition. The spiking of PYR negatively affected microbial diversity, and distinct time- and influent-dependent changes in microbial communities were observed. The relative abundance of PAH-degrading microorganisms increased in PYR-spiked systems, while the abundance of nitrifiers decreased. The addition of media amendments was beneficial for the enrichment of microorganisms that are more resistant to PYR-related stress, therefore elevating the COD concentration removal rate by ∼50%. This study gives new insight into the multifaceted impacts of HMW PAH accumulation on microbial fingerprinting and enzyme activities, which may provide guidance on better stormwater management practices via bioretention in terms of improved system longevity and performance.

Optimizing agricultural biomass application to enhance nitrogen removal in vertical flow constructed wetlands for treating low-carbon wastewater

Agricultural biomass waste in rural areas has been identified as an economical solid carbon sources in constructed wetlands (CWs) for treating low C/N ratio domestic sewage. However, little information is available regarding its optimal utilization as a media amendment for enhancing nitrogen removal in CWs. In this study, vertical flow CWs with different walnut peel amendment proportions (0%, 25%, 50%, 75%) were developed to explore the effects of biomass dosage on the treatment performance, nitrous oxide (N2O) emission and microbial metabolites. Results showed that the addition of biomass significantly enhanced the denitrification performance in all CWs, and the higher total nitrogen (TN) removal efficiency (91.14–97.16%) was achieved in CWs with the optimal dosage of 25%. While the addition of biomass resulted in a slight increase in N2O emission (20.56–270.13 μg m−2 h−1) compared with control systems. Additionally, the biomass addition increased the accumulation of extracellular polymeric substances (EPS) by facilitating microbial processes. Higher total EPS production was observed in CW with 25% biomass, and the proportion of tightly bound EPS (48%) dominated in the total EPS in different CWs.

Influence of Flue Gas Desulfurization Gypsum on Phosphorus Loss from a Horticultural Growth Medium

In response to agriculture’s contribution to surface water quality, considerable effort is being made to develop best management practices to reduce nutrient loss. To evaluate the efficacy of gypsum as a horticultural media amendment for controlling phosphorus (P) leaching, flue gas desulfurization (FGD) gypsum was added to a standard horticultural growth medium at 0, 2.5, 5, 10 or 15% (v/v). FGD gypsum was either mixed with the growing medium or placed at the bottom of the containers. A fast-release or a control-release fertilizer was top-dressed to containers. The greatest P leaching occurred with the fertilizer-only treatments (no gypsum). Dissolved reactive P (DRP) losses were highest on the initial day of measurement for the fast-release fertilizer and then decreased rapidly. There was a delayed release of DRP from the controlled-release fertilizer. Increasing rates of FGD gypsum addition resulted in decreasing DRP leaching concentration loss and load. The FGD gypsum decreased leachate DRP concentration loss by a maximum of 75%, with an average decrease of 46%. Mixing the FGD gypsum with the medium (an easier/less expensive means of incorporation) was most effective with the fast-release fertilizer. These preliminary results indicate that less gypsum may be needed to reduce P loss from fast-released fertilizer as opposed to control-release fertilizer. FGD gypsum remained effective in reducing DRP loss throughout the experiment.

Behaviour of soluble reactive phosphorus within field-scale bioretention systems

Soluble reactive phosphorus (SRP) in urban runoff can contribute to eutrophication of downstream water bodies. Bioretention systems, a popular low impact development (LID) practice, have the potential to reduce SRP loads in urban runoff. In this study, six field-scale bioretention systems located in southern Ontario, Canada, with different soil media compositions were monitored to evaluate their performance with respect to SRP retention and to identify the geochemical processes influencing SRP behaviour within the systems. The physical and chemical characteristics of the soil media were analysed to compare the systems as well as to assess whether the installed soil media compositions met the LID bioretention design guidelines. To examine how SRP evolves as stormwater infiltrates through the different media, porewater was collected from multiple depths within the bioretention systems. The geochemical processes controlling SRP retention-release were identified by chemical analysis of the porewater and selective solid phase extractions. The geochemical processes governing SRP behaviour differed between the bioretention systems with processes validated via one-dimensional reactive transport simulations conducted in PHREEQC. Results indicate: 1) Soil media characteristics are highly variable between systems despite the systems having the same overall engineering design specifications; 2) Porewater SRP does not evolve uniformly with depth indicating the importance of overall system design including redox conditions, infiltration rate, and vertical layering of different materials (e.g., surface cover layer and bioretention media); 3) SRP retention-release processes often occur at shallow depth (<0.1 m) and more attention is needed to assess the impact of different surface cover layers used in field installations; 4) Hydraulic conductivity controls the residence time of water in the systems which in turn influences SRP retention-release; 5) SRP adsorption onto Al- and/or Fe-oxides is the main retention mechanism in systems with high hydraulic conductivity while Ca phosphate mineral precipitation may be important in systems with low hydraulic conductivity. The study findings provide insights needed to improve the field performance of bioretention systems in retaining SRP including the testing and application of soil media amendments for enhancing SRP retention.

Simultaneous biotreatment of hexavalent chromium Cr(VI) and polychlorinated biphenyls (PCBs) by indigenous bacteria of Co-polluted wastewater

The study was designed to isolate, identify, and characterize bacterial strains potentially capable for simultaneous biotransformation of hexavalent chromium (Cr(VI)) and polychlorinated biphenyl (PCBs) from co-contaminated site. Around 150 isolates from industrial wastewater were isolated through enrichment of minimal salt medium (MSM) with 2 mg L−1 Cr(VI). Strains capable of reducing Cr(VI) were acclimatized for biphenyl and 2-chorobiphneyl degradation by media amendment with yeast extract and biphenyl (10:90). Maximum Cr(VI) reduction was achieved in MSM at varying concertation with an average of 78% at 2 mg L−1 concentration whereas 74% Cr(VI) reduction was observed in yeast biphenyl MSM. Bacterial strains were characterized for average growth rate, doubling time, colony forming units and time to steady state. Three most efficient strains i.e., SB, K7 and K8, were identified as Pseudomonas aeruginosa (SB), Pseudomonas pseudoalcaligenes (K7), Stenotrophomonas maltophilia (K8). GC-MS analysis showed that strain K8 has significantly higher degradation potential for 2-CB and biphenyl (81% & 91% respectively), when treated individually. In simultaneous experiment, strains K7 and SB degraded 57% and 49% 2-CB respectively, whereas 56% and 55% Cr(VI) was transformed by both strains in 120 h of incubation. Results of this study showed the potential of selected bacterial strains for simultaneous treatment of Cr(VI) and PCBs in water bodies.

Effect of Wood-derived Biochar as Growth and Development Medium for Kiwifruit Seedlings

Application of biochar as a soil amendment has gained attention as a sustainable technology for environmental remediation. However, information on its use as a growing medium amendment in Bhutanese context is presently unavailable. Hence, this study assessed biochar’s physical and chemical properties as well as the response of kiwifruit seedlings to biochar-amended media. Kiwifruit seedlings were grown in different locally available organic growing media containing different quantities of wood biochar. Seven different media namely: treatment 1 (compost, 100%), treatment 2 (wood biochar + compost, 25%: 75%), treatment 3 (wood biochar + compost, 50%: 50%), treatment 4 (wood biochar + compost, 75%: 25%), treatment 5 (wood biochar, 100%), treatment 6 (wood biochar + rice husk, 50%: 50%); and treatment 7 (wood biochar + vermicompost, 50%: 50%) were used. Treatments containing biochar recorded higher pH, implying biochar addition in acidic soil reduces liming need. Kiwifruit seedlings responded significantly to the biochar-amended medium as compared with the unamended controls. This was reflected in the plant growth parameters: plant girth, plant height, taproot length and the number of lateral roots. A significant effect (P≤0.05) in seedling girth (6.60 mm), height (68.60 cm), taproot length (44.40 cm), and lateral roots (25 numbers) was observed in treatment 2 (amended with 25% wood biochar). Likewise, medium prepared with 100% wood biochar (treatment 5) resulted in a minimum effect on all parameters. Our study reveals that biochar amendment can be a method for generating carbon offsets, but at quantities exceeding 25% of the total medium, no significant effect on the overall growth of plants is achieved.

Interaction Effect of Soilless Media and Organic Amendments for Eco-Friendly Root-Knot Nematode Management in Brinjal and Tomato Nursery

Brinjal and tomato are the most important transplanted vegetable crops of the Solanaceae family. The successful cultivation of these crops is vital for meeting the nutritional dietary requirement of India’s population and earning foreign exchange for the country by exporting vegetables to foreign countries. However, there are several abiotic and biotic impediments in the cultivation of these crops. Among biotic impediments , plant-parasitic nematodes have become one of the critical factor adversely affecting the cultivation of these vegetables. In general, Meloidogyne spp. (root-knot nematode) is the most common, widespread and economically damaging plant parasitic nematode species in tomato and brinjal crop. In addition to the damage caused by root – knot nematode, it stimulates the entry of soil-borne pathogens leading to development of the disease complex. The present study was undertaken to study the interaction effect of soil &amp; soilless growing media viz. cocopeat and vermicompost along with organic amendments i.e., Trichoderma, AM fungus, and Cabbage residue incorporated individually as well as in different combinations for eco-friendly root-knot nematode management in brinjal and tomato nursery. The results indicated that treatment C-8 (Cocopeat + Trichoderma + AM fungus + Cabbage residues) recorded the superior germination count, germination percentage, days to 50% germination, root length, shoot length, fresh weight, root weight, shoot weight and root: shoot ratio. It is pertinent to mention that the soilless media, along with various organic amendments, were found to be superior for all the root and shoot attributes as compared to the conventional soil media for growing healthy nursery of tomato and brinjal in root knot nematode infested geographies. Our findings provide an effective and sustainable method of growing healthy plant nursery in nematode infested regions.

Potassium-enriched clinoptilolite zeolite mitigates the adverse impacts of salinity stress in perennial ryegrass (Lolium perenne L.) by increasing silicon absorption and improving the K/Na ratio

Salinity is a major abiotic stress that adversely affects turfgrass growth. Clinoptilolite zeolite, a silicon (Si)-rich mineral, may allow these plants to cope with salinity. Therefore, in the present study, the effects of ordinary clinoptilolite zeolite (OZ) and potassium-enriched clinoptilolite zeolite (K-EZ) on the growth of perennial ryegrass (Lolium perenne L.) were assessed under salinity stress. Perennial ryegrass seeds were cultured in soil mixtures amended, or not, with OZ or K-EZ, then exposed to three salinity levels (0, 50 or 100 mM NaCl) for three months. Control plants were grown in the same soil mixture without zeolites, but not exposed to salinity. In salinity, the application of both types of zeolite significantly decreased Na content by 44.36% and 21.31%, but increased K content by 272.34% and 81.59%, as well as the K/Na ratio by 590.47% and 129.43%, in shoots and roots, respectively, compared to the no-zeolite treatment. Similarly, Si content in shoots increased by 28.33%. Amending the soil mixture with zeolite, especially K-EZ, enhanced relative water content, membrane stability index, total chlorophyll content, total soluble proteins, peroxidase and superoxide dismutase activities but reduced the contents of total soluble carbohydrates, hydrogen peroxide, and malondialdehyde in saline conditions. Shoot and root dry weight, root volume and root/shoot ratio also improved. Soil amendment with both forms of zeolite, as a Si-rich mineral, partially offset the negative impacts of salinity on perennial ryegrass, although K-EZ had more noticeable positive and beneficial effects. The amendment of growth media with zeolite may be an effective sustainable management practice for turfgrass used in landscaping and sports fields exposed to saline water.