Soil Amendment Research Articles

Bottom-up effects of bamboo-charcoal soil amendment on the tomato insect pest Bemisia tabaci

Bottom-up effects of bamboo-charcoal soil amendment on the tomato insect pest Bemisia tabaci

The role of soil amendments in limiting the leaching of agrochemicals: Laboratory assessment for copper sulphate and dicamba

Agriculture is among the major contributors to soil and groundwater pollution, primarily through the widespread leaching of pesticides and fertilizers from crops, as well as accidental releases from point sources. Therefore, alongside restrictions on the use of highly soluble agrochemicals and enhanced application guidelines, there is a significant demand for low-impact and cost-effective solutions aimed at reducing the mobility of agrochemicals in the soils. This study evaluates the potential of soil amendments—commonly used to enhance soil structural properties, water holding capacity, and fertility—to also absorb highly soluble pesticides, thereby controlling their leaching into the subsoil. Specifically, zeolite, biochar, and milled corncob were examined in laboratory tests under static (batch tests) and dynamic (column leaching tests) conditions to assess their effectiveness in adsorbing two widely used pesticides, copper sulphate and dicamba. Batch adsorption tests were performed using the amendments as pure materials and in mixtures with sand at various application rates (1–20% by weight). The highest affinity to copper sulphate was recorded for biochar, while dicamba exhibited a higher affinity to corncob, thanks to its higher content of organic carbon. Column leaching tests, performed at an amendment application rate of 5%, confirmed the different affinity observed in batch tests among pesticides and amended soil. Less than 2% of copper sulphate leached out from biochar- and zeolite-sand columns, while a recovery of 10% and 56% was observed for the corncob-sand mixture and for pure sand, respectively. Dicamba leaching from biochar- and corncob-sand columns was halved compared to pure sand. In conclusion, the tested soil amendments resulted highly effective in reducing pesticide leaching, opening the way for their possible applications in agriculture to reduce or prevent both diffuse and punctual contamination.

Enhancing soybean cultivation sustainability: impact of limestone mining co-products on soil and plant chemical attributes

The increasing demand for sustainable agricultural practices necessitates innovative solutions for soil fertilization. This study aimed to assess the viability of using limestone mining co-products from the Irati and Corumbataí Formations as multi-nutrient sources for Glycine max cultivation. The experiment utilized a double factorial design (7 × 2) with five replications, randomly arranged and placed in pots within a greenhouse. The factors examined were the type of co-product (sedimentary rocks from the Irati Formation: rhythmite and bituminous shale; and the Corumbataí Formation: clayey siltstone) and the soil type (Haplic Arenosol and Rhodic Ferralsol). Soil ion content was assessed at 21 and 140 days after treatment application. Each pot housed four G. max plants, with leaf harvest occurring after 42 days of growth. Macronutrient content, leaf production, and soil ion availability were determined thereafter. Overall, co-product application led to increased soil pH and availability of essential ions, including K+, Mg2+, Ca2+, P, S-SO42−, and Si. At 140 days, rhythmite was notably effective in increasing pH, Ca2+, and Mg2+ in Haplic Arenosol, with respective increases of 22%, 224%, and 696%. Bituminous shale, on the other hand, significantly increased S-SO42− content by 67% and 426% in Rhodic Ferralsol and Haplic Arenosol, respectively. Moreover, the application of co-products resulted in enhanced accumulation of K, Ca, Mg, and S in G. max plants, alongside increased leaf production. In conclusion, the utilization of mining co-products positively influenced soil and plant chemical attributes, particularly enhancing leaf production in G. max. These findings highlight the potential of co-products as environmentally friendly solutions for soil fertilization, supporting sustainable agricultural practices. This research highlights a significant step towards sustainable agriculture by recycling mining waste into valuable soil amendments, which can improve crop yields and reduce the environmental impact of both mining and agricultural activities.Graphical

Optimizing native vegetation establishment in urban soils: Assessing the impacts of organic amendments on specific growth parameters

Following soil disturbances, establishing healthy roadside vegetation can reduce surface water runoff, improve soil quality, decrease erosion, and enhance landscape aesthetics. This study explores the use of organic soil amendments (OAs) as alternatives to conventional vegetation growth approaches, aiming to provide optimal compost mixing ratios for poor soils, and clarify guidelines for OAs’ use in roadside projects. Three sandy loam soils and one loam soil were chosen for the study. Organic amendments included yard waste (Y), food waste (F), turkey litter and green waste-based (T) composts, and wood-derived biochar (B). Treatment applications targeted specific increases in the organic matter (OM) percentage of the soils. A selection of seven native species (grasses and forbs) in a total of 156 pots (4 control soils + 4 soils x 4 OAs x 3 application rates, all prepared in triplicates) was used for the pot study experiment. A significant correlation between electrical conductivity (soluble salts) in soil-OA blends and corresponding percent green coverage (%GC) was found. High salts from the T compost either delayed or curtailed growth. Notably, 3 out of the 4 soils amended with biochar exhibited rapid vegetation coverage during initial growth stages compared to other soil-OA blends but reduced the nitrogen (N) uptake and leaf area in black-eyed Susan (BES) plants. In contrast, N uptake was higher in the BES plants emerging from composts T, F, and Y compared to biochar. It is recommended to minimize concentrated manure-based (e.g., turkey litter) composts for roadside projects as an OM source, and alternatively, enriching wood-based biochar with nutrients when used as a soil amendment. Within the current study, composts such as F and Y were well-suited to establish healthy and long-lasting vegetation.

Effect of Cumulative Amendment of Soil with Fly Ash in Combination with Other Nutrients on Change in Grain Yield, Crude Protein, NPN and True Protein Contents of Rice

An experiment was planned and conducted at Instructional Farm (IF), Odisha University of Agriculture & Technology (OUAT), Bhubaneswar in the years 2022 and 2023 during the Kharif seasons to study the effect of the cumulative addition of nine varieties of nutrients on the yield and protein contents of two varieties of rice namely Gayatri and Vandana. The applied fly ash (FA) was alkaline in nature whereas the soil was acidic. The grain yield of the Kharif crop in 2022 (Gayatri) varied from the lowest of 31.56 qha-1 to the highest of 37.21 qha-1. It varied from the lowest of 38.66 qha-1 to the highest of 43.82 qha-1 in 2023. The crude protein content varied from the lowest of 7.97% to the highest of 9.16% in 2022 but it varied from the lowest of 7.31% to the highest of 8.39% in 2023. The non-protein nitrogen (NPN) content varied from the lowest of 7.97% to the highest of 9.16% in 2022 but it varied from the lowest of 7.31% to the highest of 8.39% in 2023. The true protein content varied from the lowest of 6.90% to the highest of 7.97% in 2022 but it varied from the lowest of 6.12% to the highest of 7.50% in 2023. It was observed that the grain yield, crude protein, non-protein nitrogen (NPN) and true protein content decreased by the application of FA over control (only NPK fertilizer). The crude protein content decreased in all the treatments in 2023 over its 2022 counterpart whereas NPN increased by the cumulative addition of nutrients. This resulted in higher values of true protein content in the grains in the year 2023. Grain yield increased in all the treatments in 2023 over the previous year resulting in higher yield of true protein content. Hence more amount of protein rich grains per hectare can be obtained by the cumulative addition of nutrients in spite of varietal difference of the grains.

Optimization of soil hydrological properties in degraded grasslands by soil amendments

Soil amendments facilitate the restoration of degraded soil fertility and vegetation productivity. Soil hydrological functions are crucial for assessing soil degradation and restoration in grassland ecosystems. However, the manner in which soil amendments drive changes in the hydrological properties of grassland ecosystems at different soil depths remains unclear. In this study, we conducted a five-year soil amendment experiment in a semi-arid grassland of the Loess Plateau to evaluate the impact of aluminum sulfate (AS) and biochar (BC), both individually and in combination, on the hydrological properties of soil profiles. The results showed that AS significantly increased saturated water-holding capacity (SWHC) by 19.04 %, field capacity (FC) by 27.39 %, soil water storage (SWS) by 1.57 %, and saturated hydraulic conductivity (Ks) by 19.03 % in the upper soil layer (0–40 cm). BC application increased SWHC by 20.09 %, FC by 17.56 %, SWS by 12.94 %, and Ks by 16.66 % in the 0–40 cm soil layers. The combined effects of AS and BC optimized the soil hydrological properties by increasing SWHC, FC, SWS, and Ks by 25.74 %, 35.45 %, 18.47 %, and 25.80 %, respectively. These improvements were driven by significant changes in the soil organic matter, fine root biomass, total porosity, clay content, and soil bulk density. Notably, the soil amendments did not significantly affect the hydrological properties of the deep soil layer (40–80 cm). Our study demonstrated that the strategic use of AS and BC, particularly in combination, effectively enhanced soil fertility and hydrological functions, thereby increasing grassland ecosystem productivity. These findings offer critical insights for sustainable grassland management and highlight the potential of tailored soil amendments to restore and improve soil fertility and plant productivity in degraded grassland ecosystems.

The biostimulatory effect of humic‐based soil amendment on plant growth, root nodulation, symbiotic nitrogen fixation and yield of field pea (Pisum sativum L.)

AbstractIntroductionPea is one of the most important pulse legumes globally due to its high protein, which is due to its ability to fix atmospheric nitrogen through a symbiotic relationship with nitrogen‐fixing rhizobia. Symbiotic nitrogen fixation (SNF) should be optimized to maximize nitrogen fixation and achieve higher yields with more grain protein. The use of humic‐based soil amendments in crop production has garnered considerable attention in recent years due to their biostimulatory effect in improving plant growth, yield, nutritional quality and soil health. This study examines the impact of a humic‐based soil amendment (Humalite) on root nodulation, SNF, plant growth, yield and grain protein of pea.Materials and MethodsChemical characterization was performed using Fourier transform infrared spectroscopy (FTIR). Pea plants inoculated with Rhizobia were grown in pots under greenhouse conditions with five different Humalite rates (0, 200, 400, 800 and 1600 kg ha−1). SNF capacity was assessed using the 15N‐isotope dilution method.ResultsFTIR analysis revealed the abundant presence of hydroxyl (‐OH) and carboxyl (‐CO) functional groups in Humalite. Plants treated with Humalite displayed augmented root traits [root length (21%–50%), root surface area (24%–51%), volume (26%–53%), average nodule weight (11%–91%)], plant biomass [shoots (13%–29%) and roots (29%–54%)], shoot nitrogen concentration (12%–33%), shoot total nitrogen content (38%–53%), percentage nitrogen derived from the atmosphere (8%–14%) and total shoot nitrogen fixed (48%–80%) compared to the control plants at the flowering stage. Furthermore, at seed maturity stage, plants treated with Humalite at 400 and 1600 kg ha−1 exhibited a significant increase in plant biomass (4%–14%), number of seeds (8%–16%), seed weight (3%–11%), seed nitrogen content (8%–20%) and total seed nitrogen fixed (7%–22%) compared to the control plants.ConclusionsThese findings demonstrate that humic‐based soil amendment can effectively enhance plant growth, root nodulation, SNF and seed yield, thereby supporting sustainable agricultural practices.

Application of Phosphogypsum as Soil Amendment in Karst Farmlands and Its Environmental Impact Assessment

Application of Phosphogypsum as Soil Amendment in Karst Farmlands and Its Environmental Impact Assessment

Crop Residue Biochar Rather Than Manure and Straw Return Provided Short Term Synergism Among Grain Production, Carbon Sequestration, and Greenhouse Gas Emission Reduction in a Paddy Under Rice‐Wheat Rotation

ABSTRACTReturn of crop residues directly as straw, animal manure, or biochar are recommended management options for biowaste recycling and soil organic carbon (SOC) maintenance in agriculture. However, to address the soil health challenges associated with soil degradation and climate change, it is critical to determine if or which of these different forms of crop residues could deliver a synergic improvement in SOC storage, emission reduction, and crop productivity following field application. In this study, maize straw in the form of air‐dried biomass (CS), manure via cattle digestion (CM), and biochar via pyrolysis (CB) was respectively amended once at a dose of 10 t C ha−1, in comparison to no maize straw addition (CK), in a paddy field under rice‐wheat rotation. Changes in soil properties, SOC storage, greenhouse gas (GHG) emissions, and rice/wheat yield were examined over two consecutive rice/wheat rotation cycles following soil amendment. The total rice grain yield considerably increased by 6% under CM and CB, while it reduced by 6% under CS compared to CK. Soil nutrient content persistently increased under CM and CB by 4.2% ~ 17% and 11% ~ 26% for total nitrogen, 26% ~ 61% and 20% ~ 53% for available P, and 2% ~ 82% and 30% ~ 115% for available K, respectively. Topsoil SOC storage increased considerably by 8% under CM and 20% under CB, while remained unchanged under CS, compared to CK. The total methane (CH4) and nitrous oxide (N2O) emissions were considerably increased by 7 folds and 15% under CS and 3.5 folds and 61% under CM, respectively, compared to CK. In contrast, these emissions considerably decreased under CB by 33% for CH4 and 29% for N2O. Consequently, the C emission efficiency considerably reduced under CS and CM but increased under CB over the two rotation cycles monitored. Moreover, the soil quality index (SQI) considerably improved under CM and CB but remained unchanged under CS compared to CK. Among the different forms of straw return, manure, and biochar, straw amendments differed considerably in their effects on C sequestration, GHG emissions, and crop productivity. Only biochar from crop residues synergistically improved these functions in the short‐term following application to paddy soil.

Prospects and limitations of soil amendment and irrigation techniques for the water-saving public urban greenery and ephemeral weed management in the sandy soils of the United Arab Emirates

Prospects and limitations of soil amendment and irrigation techniques for the water-saving public urban greenery and ephemeral weed management in the sandy soils of the United Arab Emirates

Characteristics of rain tree seed (Samanea saman) biochar at different pyrolysis temperatures

Abstract A Rain trees (Samanea saman) yield abundant seeds, averaging 200-250 kg of pods per season from mature trees. This high seed production often results in waste or undesired seedlings. To mitigate this issue, researchers are studying methods to utilize these seeds effectively. One promising approach involves converting rain tree seeds into biochar through pyrolysis, a process that transforms organic resources into valuable products. However, the characteristics of the biochar depend on the pyrolysis temperature. This study aims to examine how different temperatures affect the properties of rain tree seed biochar. The seeds were subjected to pyrolysis at temperatures of 300°C, 400°C, 500°C, and 600°C for four hours. The results show that increasing the pyrolysis temperature will decrease the biochar yield, with the highest yield at 300°C being 50.52%. Conversely, the ash content and fixed carbon increase with rising temperatures. SEM analysis indicates that pores begin to form at 400°C; however, at 600°C, extensive pore cracking is observed. Based on FTIR analysis, functional groups including -OH, C=C, C=O, C-O, and C-H were identified. XRF analysis reveals that the four dominant elements in biochar are K2O (55-59%), CaO (24-28%), P2O5 (11-12%), and MgO (1.5-1.9%). Based on these dominant elements, rain tree seed biochar has potential for soil amendment, containing macronutrients necessary for plant growth.

Combined Application of Biochar and Silicon Fertilizer for Improved Soil Properties and Maize Growth

Biochar can be a good soil amendment to reduce the soil pH, increase crop growth rate, and improve the efficient use of fertilizer. Other than that, silicon fertilizer also would promote photosynthetic ability on plant development that would help to produce high yield. In this work, a series of experiments was conducted to observe the effect of rice husk biochar and silicon fertilizer on the maize growth rate and soil pH. A 45-day pot experiment in the greenhouse with three replicates of 9 experimental treatment combinations of RHB at two rates (5 and 2.5 t.ha-1) with silicon fertilizer at three rates (125%, 100%, 75%), sole biochar (10 t.ha-1), sole silicon fertilizer (100%) and control (NPK) to observe the best rate and combination to improve growth rate and change in soil chemical in acid soil. The result showed that the co-application of sole biochar and biochar with Silicon significantly improved growth development, increased photosynthesis rate, altered soil pH, and reduced Fe concentration compared to control. The plant height increased 88.35% from T4 (5 t.ha-1 RHB + 100% Si) compared to the control and the conductance was higher in T4 (0.53) followed by T8 (0.438) while T1 (0.071) recorded the lowest conductance. The shoot fresh weight was higher in T4 (127.83 g) followed by T8 (57.14 g). However, the weight increased by 343.7% at T4 followed by T8 (2.5 t.ha-1 RHB + 75% Si) at 98.33%. The highest pH increment of 1.24 units (T1 = 5.53, T4 = 6.77) of soil pH was noted from T4 (5 t.ha-1 RHB + 100% Si) compared to control (NPK), and the highest total Fe in soil was observed from T1 (442.30 mg.kg-1). The current study results showed that T4 (50% RHB + 100% Silicon) was the best treatment over the other rates of RHB and silicon increased plant height, photosynthetic rate, and biomass.

Evolution of Cu and Zn speciation in agricultural soil amended by digested sludge over time and repeated crop growth

Metals such as Zn and Cu present in sewage sludge applied to agricultural land can accumulate in soils and potentially mobilise into crops. Sequential extractions and X-ray absorption spectroscopy results are presented that show the speciation changes of Cu and Zn sorbed to anaerobic digestion sludge after mixing with soils over three consecutive 6-week cropping cycles, with and without spring barley (Hordeum vulgare). Cu and Zn in digested sewage sludge are primarily in metal sulphide phases formed during anaerobic digestion. When Cu and Zn spiked sludge was mixed with the soil, about 40% of Cu(I)-S phases and all Zn(II)-S phases in the amended sludge were converted to other phases (mainly Cu(I)-O and outer sphere Zn(II)-O phases). Further transformations occurred over time, and with crop growth. After 18 weeks of crop growth, about 60% of Cu added as Cu(I)-S phases was converted to other phases, with an increase in organo-Cu(II) phases. As a result, Cu and Zn extractability in the sludge-amended soil decreased with time and crop growth. Over 18 weeks, the proportions of Cu and Zn in the exchangeable fraction decreased from 36% and 70%, respectively, in freshly amended soil, to 28% and 59% without crop growth, and to 24% and 53% with crop growth. Overall, while sewage sludge application to land will probably increase the overall metal concentrations, metal bioavailability tends to reduce over time. Therefore, safety assessments for sludge application in agriculture should be based on both metal concentrations present and their specific binding strength within the amended soil.

Effect of Chicken Feather Hydrolysate on Growth of Spinach through Soil Amendment Method: Unraveling A Potential Liquid Biofertilizer

The study aims to investigate the effectiveness of chicken feather hydrolysate for promoting the growth of Spinacia oleracea L., a commonly consumed leafy green vegetable. An earlier isolated and identified keratinolytic bacterial species Bacillus tropicus was utilized for the preparation of chicken feather hydrolysate through submerged fermentation. Minimal media which was supplemented with chicken feather was used for the preparation of hydrolysate. The bacterial strain degraded chicken feather within 4 days of incubation after which the feather hydrolysate was collected and tested to check plant growth promoting activity through the seed germination trials and greenhouse study. Upon characterization of feather hydrolysate, it was found that the hydrolysate was a cocktail of Nitrogen, Phosphorus and Potassium (NPK) as well as other micro elements needed for plant growth. Four different concentrations of feather hydrolysate were employed for both the seed germination and greenhouse study which ranged from 25% (v/v), 30% (v/v), 35% (v/v) and 40% (v/v) including a control group (CN) which was not supplemented with feather hydrolysate. The hydrolysate supplementation brought about plant growth in all the four test concentrations with 35% (v/v) giving the highest result of 14 cm and 27.6 mg/g for tested parameters like plumule length and total chlorophyll content, respectively. The same concentration supported maximum seed germination and highest radicle extension for the germination studies as well. This study investigates the efficacy of chicken feather hydrolysate in promoting spinach growth, elucidating its potential as a fertilizer.

Assessment of the benefits and risks of sewage sludge application as soil amendment for agriculture in Eswatini

Sewage sludge is an important soil conditioner, and source of nutrients with a potential for use in agriculture. However, such benefit needs to be weighed against the risks due to the presence of heavy metals, and other substances that may endanger human health, plants, soil and the ecosystem. This research had the objective of evaluating the agricultural potential of sewage sludge together with the risks that may be present in use. Samples of sewage sludge from seven wastewater treatment plants in Eswatini were analyzed for selected physical and chemical parameters, and heavy metal concentrations using commonly established laboratory procedures. The analysis results indicated that, sludge samples exhibited high organic matter content, cation exchange capacity, macro nutrients such as nitrogen and phosphorus and micro nutrients (trace metal elements) needed for plant growth. Anaerobically digested sludge samples showed higher carbon to nitrogen ratio because of biomass loss in the form of methane and carbon dioxide. The heavy metal concentrations are all within safe limits except the sludge from Matsapha area that had levels of chromium, and nickel above regulatory limits. With respect to their heavy metal contents, most of the sludge samples would qualify as Class A sludge ready to be used as organic fertilizer for agriculture without regular monitoring of heavy metals in the soil to which they are applied. The study results indicated the importance of sewage sludge for their agricultural potential through supplementation of both micro and macro nutrients needed for plant growth, for improving the soil properties such as water holding capacity and permeability, through the increase of organic matter content, and retention of nutrients due to the high cation exchange capacity. All these benefits are realized with sewage sludge being a lower cost alternative to commercial fertilizers. Moreover, the low concentration of heavy metals present in the sludge presents lower risk that may arise in the course of utilizing the sludge as agricultural supplement. Key words: Agriculture, fertilizer, heavy metals, nutrient, sewage, sludge, nitrogen, phosphorous

Unde venis? Bacterial resistance from environmental reservoirs to lettuce: tracking microbiome and resistome over a growth period.

Fresh produce is suggested to contribute highly to shaping the gut resistome. We investigated the impact of pig manure and irrigation water quality on microbiome and resistome of field-grown lettuce over an entire growth period. Lettuce was grown under four regimes, combining soil amendment with manure (with/without) with sprinkler irrigation using river water with an upstream wastewater input, disinfected by UV (with/without). Lettuce leaves, soil, and water samples were collected weekly and analysed by bacterial cultivation, 16S rRNA gene amplicon sequencing, and shotgun metagenomics from total community DNA. Cultivation yielded only few clinically relevant antibiotic-resistant bacteria (ARB), but numbers of ARB on lettuce increased over time, while no treatment-dependent changes were observed. Microbiome analysis confirmed a temporal trend. Antibiotic resistance genes (ARGs) unique to lettuce and water included multidrug and β-lactam ARGs, whereas lettuce and soil uniquely shared mainly glycopeptide and tetracycline ARGs. Surface water carried clinically relevant ARB (e.g. ESBL-producing Escherichia coli or Serratia fonticola) without affecting the overall lettuce resistome significantly. Resistance markers including biocide and metal resistance were increased in lettuce grown with manure, especially young lettuce (increased soil contact). Overall, while all investigated environments had their share as sources of the lettuce resistome, manure was the main source especially on young plants. We therefore suggest minimizing soil-vegetable contact to minimize resistance markers on fresh produce.

Low-energy thermo-chemical conversion processes of municipal wet waste

Hydrothermal carbonization (HTC) is a low-energy thermochemical process that converts wet biomass into a carbon-rich solid, commonly called hydrochar, for use in a variety of areas, such as soil amendment, biofuels or to produce carbon-based materials. The purpose of this paper is to increase knowledge for the economic valorization of municipal wet waste, considered as a raw material to obtain high value-added products through an HTC process and an additional chemical activation procedure. In the first part of the work, a 4.5-liter batch reactor was designed, built, and used in the HTC experimental campaign by varying the main process parameters, namely reaction time, amount and type of organic waste (e.g. vegetables, fruits, bread, pasta), water concentration, temperature and pressure. In addition, some experiments were conducted by applying the steam explosion technique at the end of the HTC process. The HTC results showed that in biomass with high water content, increasing residence time decreases the hydrochar yield. Considering a dry heterogeneous waste with high carbon content, the yields at the end of the process are much higher. In the second part of this work, the hydrochar samples were treated with a high-temperature activation process based on the use of KOH, obtaining activated carbon. Particularly, the best results were achieved by using high KOH: hydrochar ratios, resulting in high-quality activated carbons with good porosity and a high surface area of 2890 m2/g. Finally, an energy analysis was carried out to evaluate how to make the whole process cost-effective.

Optimization of peapod peel biochar amendment for sustainable agriculture by surface response methodology towards water-food-environment nexus

Valorization of food waste to biochar offers economic and environmental opportunities for sustainable agriculture production. Peapod (Pisum sativum) peel is a high-content lignocellulose vegetable waste and was used in this study to produce biochar through pyrolysis temperatures of 350, 450, and 550 °C, with a heating rate of 5 °C/min for 30 min and thereafter characterized for its various properties. The biochar produced at 350 °C, exhibiting the best soil amendment properties was used for pot testing with mung bean (Vigna radiata). The optimization of plant growth, soil water retention capacity, and microbial activity were determined using response surface methodology (RSM) with three design factors: (a) biochar loading rates (0 %, 0.5 %, and 1 %), (b) temperature (30–40 °C), and (c) quantity of water supplied (50–60 mL/day). The results showed that applying 0.5 % biochar with a water supply of 55 mL/day at 35 °C resulted in optimal responses for seed germination, plant height, and leaf development. Applying 1 % biochar with a water supply of 55 mL/day at 35 °C showed optimal responses for leaf area and leaf chlorophyll content. Stomatal conductance and catalase activity showed optimal responses for 1 % biochar applied with a water supply of 60 mL/day at 40 °C. Urease activity and water retention capacity showed optimal responses when 1 % biochar was applied with a water supply of 60 mL/day at 30 °C, respectively. This study demonstrates the potential use of peapod peel biochar in water-food-environment nexus, with a lower dose and lesser volume of water demand.

Effect of Almond Residue Soil Amendments and Irrigation Regiment on Organic Acid Development and Transport in Soil

Effect of Almond Residue Soil Amendments and Irrigation Regiment on Organic Acid Development and Transport in Soil

Impact assessment of Zeolite, Ca-bentonite and Biochar amendments on Cd bioavailability and fractions in polluted calcareous soils

The refining of polluted soils by heavy elements is one of the most important environmental policies in industrialized and developing countries. Using adsorbents is a suitable procedure for the immobilization of heavy metals in polluted soils. This study aimed to assess the immobilization of Cadmium (Cd) in polluted calcareous soil affected by the application of organic and inorganic amendments including Biochar (from grape pruning residues) and natural Zeolite and their interaction under wheat cultivation. The treatments used in this study were two amendments of Zeolite and Biochar (from grape pruning wastes) at three levels (0, 1, and 4%) and three levels of Cd contamination (0, 75, and 150 mg/kg soil). A 16-week incubation period was considered for the homogenization of the amendments in soil and wheat was grown according to the standards procedure. At the end of incubation, different fractions of Cd including residual, exchangeable, bonded to organic matter, bonded to carbonate and bonded to iron and manganese. Also available Cd by DTPA and EDTA methods and 1000-grain weight of wheat were measured. The results showed that the highest amount of Cd bound to organic matter was obtained in 4% Biochar treatment to 15 mg/kg. The highest and lowest amounts of Cd extracted with DTPA were obtained in the control one (92 mg/kg) and the level of 4% Biochar (67 mg/kg), respectively. The results showed that increasing the amount of Biochar and Zeolite amendments increased the weight of 1000 grains of wheat in all treatments. According to the results of the study, the use of Biochar and Zeolite reduced the amount of Cd extracted by DTPA ( 82.436 mg/kg) and EDTA (115.605 mg/kg). Finally, the results showed that the use of Biochar and Zeolite has reduced active Cd and its mobility in the soil due to increasing organic and carbonate fractions. Combining biochar and zeolite in soil remediation efforts can enhance their effectiveness in reducing the concentration and mobility of active Cd. The biochar provides a stable carbon matrix for long-term immobilization of Cd, while the zeolite offers additional adsorption capacity and ion-exchange capabilities. This synergistic effect can lead to improved soil quality and reduced environmental risks associated with Cd contamination.