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The agri-food industry, produces organic residues that could be reused as fertilizer, thereby allowing the recycling of nutrients for crops and the replacement of mineral fertilizers. In this context, here we examined the capacity of anaerobic digestates and mixed residues (digestates plus spent mushroom substrates) to supply nutrients to lettuce (Lactuca sativa L.) grown in a greenhouse experiment. Moreover, the potential leaching of nutrients into the soil was evaluated in a column assay. The results obtained from organic residues treatments were then compared to those achieved in soil treated with mineral fertilizer and in untreated soil. Digestates treatments minimized the potential risk of nitrate (NO3−) leaching by allowing the slow release of NO3− maintaining crop yield. Given our observations, this type of organic residues emerges as an alternative to mineral fertilizer. The loss of NO3−-N from the total amount of N applied reached ∼3% in the mixed residues treatments, 36–46% in the digestate treatments, and 68% in the mineral fertilizer treatment. The mixed treatments showed low available N content as a result of immobilization in the soil, which is a limiting factor for crop production. Moreover, the organic residues treatments had no negative effect on lettuce seed germination or plant growth with respect to parameters such as chlorophyll, total polyphenols, and heavy metals in aerial biomass. The findings reported herein contribute to a better understanding of nutrient availability provided by organic residues materials and the capacity of these amendments to replace mineral fertilizers and avoid nutrient loss by leaching. Digestate treatments showed a similar capacity to maintain lettuce production as mineral fertilizer. Mixed treatments did not provide mineral N for the crop by N immobilization in soil. Nitrate loss when organic residues were applied was lower than for the mineral fertilizer treatment. Soil amendment with organic residues has no negative effects on lettuce yield. Digestates emerge as an alternative to mineral fertilizers for lettuce production, reducing soil nutrient loss. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) of dairy manure digestate (DMD) was explored in this study. Response surface methodology was used to investigate the influence of temperature, time, and DMD pH on hydrochar properties. Hydrochar obtained in the study exhibited higher heating value (HHV) in the range of 17.5–20.6 MJ kg−1, with energy and hydrochar yields 45.8–72.4% and 57.6–80.1%, respectively. It was demonstrated that temperature was the most significant factor. At higher temperature, the HHV of hydrochar was higher while both energy and hydrochar yields were lower. In particular, hydrochar obtained at temperature ≥ 260 °C had HHV ≥ 20.0 MJ kg−1, which was close to that of lignite and implied its potential as fuel. To gain insights about the fate of various elements during HTC and facilitate overall evaluation of hydrochar, a wide range of elements (30 in total, including macro- and micro-nutrients, as well as heavy metals) was analyzed. Hydrochar had carbon to nitrogen (C/N) ratio between 10 and 12, which was in the suitable range for nutrient availability as soil amendment. Half of the elements remained in the hydrochar, while most of Na, K, and half of S leached into process water, especially at temperature ≥ 260 °C, thus combusting hydrochar can potentially alleviate the slagging and fouling problems associated with direct combustion of dried DMD. The study provided insights for further rational utilization of DMD hydrochar, and integration of HTC into existing on-farm anaerobic digestion was a promising option for reduction disposal of DMD. [ABSTRACT FROM AUTHOR]

Leonardite is an important source of organic fertilizers and soil amendment. The objective of this study was to determine the effects of increased doses of leonardite (control (L0), 20 (L20), 40 (L40), 60 (L60), and 80 (L80) t ha−1) on soil properties at different incubation times (control (T0), 15 (T15), 30 (T30), 45 (T45), 60 (T60), and 90 (T90) days). Analysis results of soil samples taken during six different incubation periods. Results showed that application of leonardite significantly improved soil organic matter (SOM), total nitrogen (N), exchangeable calcium (Ca) and, available iron (Fe), manganese (Mn) and zinc (Zn), especially with L40 and L60. Prolonged incubation time was significantly increased N, P, K, Ca, Fe, Zn concentrations especially T60 and T90. The nutrient concentration of the tomato plants was not affected by increased doses of leonardite, except for total N, Fe and Cu. By the way, prolongation of the incubation period resulted in fluctuating nutrient concentrations of the plant. As a result, it was determined that leonardite improved the chemical properties of the soils but it was not sufficient in the feeding of the tomato plant. Therefore, leonardite must be used with chemical fertilizers for plant growing. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of organic amendments on saline-alkali soil improvement were compared. • The optimal blending ratio of organic amendments was 20%. • High-temperature pretreatment compost favored soil improvement and plant growth. • High-temperature pretreatment composting improved plant antioxidant capacity. • Plant growth was improved by altering soil-dominant microflora and composition. Short-term high-temperature pretreatment can effectively shorten the maturity period of organic waste composting and improve the fertilizer efficiency and humification degree of products. To investigate the effect and mechanism of the end products on the saline–alkali soil improvement and plant growth, the short-term high-temperature pretreatment composting (SHC) and traditional composting (STC) were separately blended with saline–alkali soil in a ratio of 0–40 % to establish a soil–fertilizer blended matrix for cultivating Lolium perenne L. The pot experiments combined with principal component analysis showed Lolium perenne L. planted in 20 % SHC-blended saline–alkali soil had the best growth effect, and its biomass, chlorophyll content, and plant height were 109–113 % higher than STC. The soil physicochemical property analysis showed that SHC and STC increased the soil nutrient content, humification degree, and enzyme activity at any blending ratio. The microbial analysis showed that 20 % SHC in the saline–alkali soil stimulated the growth of functional microorganisms and the addition of SHC promoted the sulfur cycle, nitrogen fixation, and carbon metabolism in the soil–plant system. The correlation analysis showed that pH; nutrient contents; and urease, catalase, sucrase, and phosphatase activities in the saline–alkali soil were significantly correlated with plant growth indexes (p < 0.05). Georgenia and norank_f__Fodinicurvataceae had a stronger correlation with four types of enzyme activities (p < 0.01). SHC improved the saline–alkali soil and promoted plant growth by adjusting soil pH, increasing soil nutrients, and influencing soil enzyme activity and dominant flora. This study provides a theoretical basis for applying SHC products in soil improvement. [ABSTRACT FROM AUTHOR]

The use of saline water under drought conditions is critical for sustainable agricultural development in arid regions. Biochar is used as a soil amendment to enhance soil properties such as water-holding capacity and the source of nutrition elements of plants. Thus, the research was carried out to assess the impact of biochar treatment on the morphological and physiological characteristics and production of Solanum lycopersicum in greenhouses exposed to drought and saline stresses. The study was structured as a three-factorial in split-split-plot design. There were 16 treatments across three variables: (i) water quality, with freshwater and saline water, with electrical conductivities of 0.9 and 2.4 dS m− 1, respectively; (ii) irrigation level, with 40%, 60%, 80%, and 100% of total evapotranspiration (ETC); (iii) and biochar application, with the addition of biochar at a 3% dosage by (w/w) (BC3%), and a control (BC0%). The findings demonstrated that salt and water deficiency hurt physiological, morphological, and yield characteristics. Conversely, the biochar addition enhanced all characteristics. Growth-related parameters, such as plant height, stem diameter, leaf area, and dry and wet weight, and leaf gas exchange attributes, such rate of transpiration and photosynthesis, conductivity, as well as leaf relative water content were decreased by drought and salt stresses, especially when the irrigation was 60% ETc or 40% ETc. The biochar addition resulted in a substantial enhancement in vegetative growth-related parameters, physiological characteristics, efficiency of water use, yield, as well as reduced proline levels. Tomato yield enhanced by 4%, 16%, 8%, and 3% when irrigation with freshwater at different levels of water deficit (100% ETc, 80% ETc, 60% ETc, and 40% ETc) than control (BC0%). Overall, the use of biochar (3%) combined with freshwater shows the potential to enhance morpho-physiological characteristics, support the development of tomato plants, and improve yield with higher WUE in semi-arid and arid areas. [ABSTRACT FROM AUTHOR]

To meet global food demand, reduce waste, and minimise environmental impact, the agricultural sector must improve its current practices on soil amendment, fertiliser encapsulation, and seed and crop protection. Super absorbent polymers (SAPs) are a class of polymeric materials that can absorb and retain large quantities of liquids/aqueous solutions compared to their own mass. Typically, SAPs are cross-linked to form three-dimensional hydrophilic networks, commonly known as hydrogels. Although SAPs can be synthesised from both synthetic and naturally sourced materials, for agricultural applications they are generally composed of synthetic polymers, due to their advantageous properties. These include higher water absorption rate and capacity, low cost, availability, durability, and mechanical performance. However, many of these systems utilise polyacrylic acid (PAA) and polyacrylamide (PAM) monomers which may have toxic effects on the nervous and respiratory systems of humans and animals. To ensure sustainable agricultural practices and maintain healthy long-term crop output, synthetic SAP usage must be greatly reduced. This review article aims to investigate alternative natural SAPs for agriculture and critically rationalise their adoption into the industry. Specific applications investigated include (i) soil amendment, (ii) fertiliser encapsulation, (iii) seed coating, and (iv) crop protection. [ABSTRACT FROM AUTHOR]

Soil amendments have been proposed as an effective way to enhance soil carbon stocks on degraded soils, particularly in dryland farming areas. Soil organic carbon (SOC) plays an important role in improving soil quality, and soil aggregates are known to be crucial in sequestering and protecting SOC. However, how aggregation and protection of SOC by aggregates respond to a single application of bentonite combined with maize straw remains unknown, especially in the sandy soil of a semi-arid region. A three-year field experiment with four treatments [no amendment (CK), maize straw amendment addition only (T1, 6 Mg ha−1), bentonite amendment addition only (T2, 18 Mg ha−1), and maize straw combined with bentonite amendment (T3, 6 Mg ha−1 maize straw plus 18 Mg ha−1 bentonite)] was conducted in the Loess Plateau of China to assess the effects of bentonite and maize straw on aggregation and SOC. The results indicated that soil bulk density decreased by 2.72–5.42%, and soil porosity increased by 3.38–8.77% with three years of T3 application, especially in the 20–40 cm layer, compared with CK. T3 increased the amount of C input, SOC stock, and SOC stock sequestration rate by 1.04 Mg ha−1 y−1, 0.84–1.08 Mg ha−1, and 0.49 Mg ha−1 y−1, respectively, and it increased the mass proportions and aggregate-associated C stock of >0.25 mm aggregates by 1.15–2.51- and 1.59–2.96-fold compared with CK. Correlation analysis showed a positive correlation of total SOC stock with the C concentration of >2 mm, 0.25–2 mm, and 0.053–0.25 mm aggregates. Aggregates of various sizes in sandy soils have the potential for greater SOC stock. Our findings suggest that the application of maize straw (6 Mg ha−1) combined with bentonite (18 Mg ha−1) would be an effective management strategy to enhance the bulk soil C pools by improving the soil structure and thereby improving soil fertility. [ABSTRACT FROM AUTHOR]

Soil amendments such as humic acid (HA), a biochar-based microbial agent (M), and vermicompost (V) can improve soil quality and promote crop growth. However, it remains unclear whether the co-application of the three soil amendments (HMV) has a synergistic effect on alleviating soil quality deterioration obstacles caused by dry sowing and wet emergence technology in Xinjiang cotton fields. A three-year field experiment was conducted in saline–alkali soils using plastic-film-mulched drip irrigation in Xinjiang, China. Through the orthogonal experiment method, the application amounts of HA, M and V were 75 kg ha−1, 75 kg ha−1 and 225 kg ha−1 respectively in 2021. In 2022, three application amount gradients were used for HA, M and V: 60 kg ha−1, 90 kg ha−1 and 120 kg ha−1 respectively. In 2023, the application amounts of HA, M, and V were 60 kg ha−1, 120 kg ha−1, and 120 kg ha−1. It should be pointed out that V contains HA in the range of 20–35%. This study aimed to explore the improvement effect of a single or combined application of HA, M, and V on soil quality and cotton emergence rate using dry sowing and wet emergence technology in Xinjiang cotton fields. The results showed that the single and combined applications of HA, M, and V improved the soil quality and water–heat–salt environment of the cultivated layer. In the combined application, the cotton seedling emergence rate and yield increased by 1.9–22.8% and 7.0–54.1%. Therefore, it is recommended to jointly apply HA, M, and V to promote cotton seedling emergence and increase yield using dry sowing and wet emergence technology in Xinjiang cotton fields. [ABSTRACT FROM AUTHOR]

Agricultural practices alter the organic carbon dynamics in soil. An experiment was conducted to study the effect of carbon amendments, tillage, and cover cropping on permanganate oxidizable carbon (POXC), total organic carbon (TOC), and wet aggregate stability (WAS) in a 2‐year crop sequence (corn–cover crop–cotton–cover crop) at the Texas A&M Research Farm. Two carbon amendments (biochar and composted biosolid) were applied at the rate of 500 kg C ha−1, along with a control. Two tillage practices were evaluated: conventional tillage (CT) and no‐tillage (No‐Till). A cover crop (CC) mixture of oat, mustard, and pea and no cover crop (No‐CC) were also evaluated. Treatments were arranged in a split‐split plot design with four replications. Amending the soil with carbon as composted biosolid or biochar affected POXC at both the 0‐ to 5‐ and 5‐ to 15‐cm depths. The POXC was significantly higher for the biochar treated plots for corn and CC after corn but significantly lower POXC was observed after cotton with biochar‐treated plots. The POXC increased under No‐Till compared with CT and CC plots relative to No‐CC plots. The TOC was not sensitive to soil management practices. The POXC and TOC both decreased with depth. The WAS greater under No‐Till and CC plots. The POXC and WAS were influenced by soil management practices and can be useful indicators to assess short‐term soil health improvements. The POXC and WAS were positively related, suggesting that one may be used to predict the other. Core Ideas: Permanganate‐oxidizable carbon (POXC) was sensitive to management practices compared to total organic carbon.POXC was greater on no‐tillage compared to conventional tillage.POXC was higher on cover cropped than no cover cropped plots.Soil aggregate stability was positively correlated with POXC.Wet aggregate stability was greater under biochar amended, no‐tillage, and cover cropped plots. [ABSTRACT FROM AUTHOR]

• ZnO nanoparticles (NPs) were active in inhibiting growth of Fusarium oxysporum. • Plants grown in NPs-amended soil showed improved growth. • NPs caused increased activity of plant defense-related enzymes. • Plants showed enhanced expression of defense-related genes after NPs application. Management of Fusarium wilt, a destructive plant disease, mainly relies on chemicals, but research on novel and eco-friendly methods is needed due to the hazardous effects of chemical pesticides. This study explored the soil application of zinc oxide nanoparticles (ZnONPs) to manage Fusarium wilt disease in cucumber plants. The antifungal activity of ZnONPs against in-vitro growth of Fusarium oxysporum was tested through food poisoning test on the potato dextrose agar medium. The in-vivo potential of NPs for managing Fusarium wilt was checked in pot experiment. In-vitro results confirmed the concentration-dependent in-vitro antifungal activity. The NPs application at 500 µg/ml and 600 µg/ml concentrations showed phytotoxicity and significantly inhibited seed germination and growth of cucumber plants. However, NPs at 300 µg/ml significantly suppressed the pathogenic effects of F. oxysporum on cucumber plants without any phytotoxic effect. The pathogen-inoculated cucumber plants grown in soil amended with NPs showed significantly enhanced growth, lower disease severity, and improved root physiology compared to untreated plants. The plants under NPs treatment showed higher chlorophyll and nitrogen content while decreased membrane permeability and malondialdehyde content. Along with direct antifungal activity, the application of NPs caused an increased expression of defense-related genes and higher activities of defense-related enzymes. These findings verified the efficiency of ZnONPs for suppressing Fusarium wilt disease in cucumber crops, thereby promoting a non-chemical and environmentally friendly approach to controlling Fusarium wilt disease. [ABSTRACT FROM AUTHOR]

The principle of sustainable fertilisation in modern agriculture, which ensures that the soil is maintained in a fertile state requires the search for alternatives to manure fertilisation for products based on humic substances to increase the organic matter content of soils.The advantage of leonardite over conventional natural and organic fertilisers is mainly due to its high content of organic matter and humic substances (humic and fulvic acids). Leonardite, due to the presence of humic acids in it, can be suitable for soil amendment and yield of barley. In the conducted studies, the yield increase after adding Rosahumus fertilizer to the soil at a rate of 6 kg.ha−1 + NPK (Nitrogen, Phosphorus, Potasssium) was found to be 11% compared to the control (NPK).There were no changes in the Corg. content of the soil as a result of the application of Rosahumus fertilizer with NPK. The fertilizer only slightly modified the fractional composition of humus. In the future, we should expect an increase in the use of leonardite-derived humic substances in fertilizers and soil conditioners to stabilize soil organic matter. [ABSTRACT FROM AUTHOR]

Organic amendment has proven to improve soil quality and crop production, in addition to reduce resource waste. However, the effect of organic amendment on soil water-stable aggregates and soil organic carbon is unclear. A two-year field experiment with four organic amendment treatments, biochar, organic fertilizer, microbial agents and polyacrylamide (PAM), was conducted to investigate the effect of different soil organic amendments on Loess Plateau. The results revealed that organic amendments significantly influenced the mean weight diameter (MWD) and geometric mean diameter (GMD) of water-stable aggregates, particularly in the case of PAM treatment. The MWD and GMD values increased significantly by 33.7% and 29.8% in the PAM treatment. The proportion of macroaggregates (2-0.25 mm) showed a remarkable 52.9% increase compared to the control (CK) treatment in the PAM-treated soil. Biochar-amended treatments increased soil organic carbon (SOC) in all aggregate fractions compared to CK treatment. Soil organic amendments also decreased soil bulk density and increased total nitrogen (TN) and available phosphorus (AP). Compared to CK treatment, the maize yields in the organic fertilizer and biochar treated soil increased by 19.8 and 30.3%, respectively. These findings suggest that biochar and PAM amendments are particularly suitable for loessal soil in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Soil salinity is a major challenge in agriculture, particularly in calcareous soils with high calcium carbonate levels. Biochar, produced from biomass pyrolysis, is being considered as a potential solution for mitigating salinity effects. A greenhouse pot experiment was conducted using calcareous soil from a saline field to investigate the effects of sugarcane biochar applied at different rates (0.0%, 2.0%, and 5.0%) on soil properties and wheat (Triticum aestivum L.) growth. Results showed that both Low Rate (2.0% biochar) and High Rate (5.0% biochar) treatments significantly improved soil pH, reduced electrical conductivity (EC), and increased soil organic matter (SOM) content. Plant growth indicators such as plant height, stem diameter, and leaf chlorophyll content also showed significant improvement with biochar application. High Rate had more pronounced effects compared to Low Rate. The analysis confirmed the significant effects of biochar on soil properties and plant growth, indicating its potential as a beneficial soil amendment. Sugarcane biochar has the potential to mitigate salinity stress and enhance crop productivity in calcareous soils. Further research is needed to explore the long-term effects of sugarcane biochar application and its interactions with other soil management practices in different crop systems. These findings highlight the promising role of biochar as a sustainable approach for mitigating salinity stress in agriculture and improving soil quality for crop production. The study's findings highlight the potential industrial applications of sugarcane biochar in addressing soil salinity issues prevalent in calcareous soils, particularly in agriculture. The research underscores the positive impact of biochar on soil attributes, plant growth, and nutrient availability. With its ability to improve soil pH, reduce salinity, increase soil organic matter, and enhance plant growth, sugarcane biochar emerges as a promising soil amendment for agricultural use. This presents an opportunity for industries involved in sustainable agriculture, soil management, and crop enhancement to explore the integration of biochar into their practices. Additionally, the study emphasizes the need for further research and field trials to optimize biochar application rates, assess economic feasibility, and ensure environmental sustainability. The insights gained from this study offer a pathway for industrial stakeholders to explore biochar's role in enhancing soil quality, promoting plant growth, and ensuring sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

The aim of this study was the characterization and evaluation of applicability as a soil amendment of biochar derived from rose pruning waste at different pyrolysis temperatures (200–500 °C) and process durations (20–60 min). The biochar properties were compared to the raw material. The biochars produced at 300 °C for 40 and 60 min demonstrated the best fuel properties. These variants showed high energy gain rates (77.6 ± 1.5% and 74.8 ± 1.5%, respectively), energy densification ratios (1.35 ± 0.00 and 1.37 ± 0.00, respectively), high heating values (24,720 ± 267 J × g−1 and 25,113 ± 731 J × g−1, respectively), and relative low ash contents (5.9 ± 0.5% and 7.1 ± 0.3%, respectively). Regarding fertilizer properties, such as pH value, ash content, heavy metal content, and pollutant elution, the biochars showed better qualities than the raw material. All tested biochar did not exceed the permissible values for heavy metals, including Cr, Cd, Ni, and Pb. The most optimal properties for soil amendments were noted for biochar variants of 400 °C for 40 min, 450 °C for 20 min, and 500 °C for 20 min. Generally, biochars produced at temperatures ≥400 °C did not inhibit root elongation, except for the material produced at 450 °C for 60 min (4.08 ± 23.34%). Biochars obtained at ≥300 °C showed a positive impact on seed germination (86.67 ± 18.48–100 ± 24.14%). [ABSTRACT FROM AUTHOR]

Sandy and acidic soil conditions are the major factors limiting the production of some vegetable crops in acidic soils. This study aims to examine the effect of various amendments on the growth, yield and mineral nutrients uptake of stem amaranth. Two pot experiments were conducted separately in two generic soils. Six treatments viz. T0 = control (without amendment), T1= lime, T2 = lime + wetland bottom sediment, T3 = lime + vermicompost, T4 = lime + rice straw biochar (RSB) and T5 = RSB were used for both experiments following CRD with four replications. Results revealed that plant heights (45.96 and 50.33 cm) of amaranth grown in alluvial and hill soils, respectively, were the highest in T4 treatment. Similarly, treatment T4 showed the highest fresh (118.53 and 116.11 g pot−1, respectively) and dry biomasses (16.98 and 19.54 g pot−1, respectively) for both soils. For both soils, treatment T4 resulted better nutrient uptake of N, P, K, S, Zn, Fe and Mn by edible stem, while non-amended soil gave the lowest result at all parameters. Analytical values of post-harvest soils indicated that T4 and/or T5 treatments resulted in an improvement in soil pH, organic carbon, total N, exchangeable K and extractable P, S and Zn. Treatment T3 showed elevated concentrations of extractable soils Fe and Mn. The amendment RSB combined with lime can be preferably used in strong acidic soils for cultivation of stem amaranth. [ABSTRACT FROM AUTHOR]

Phaseolus vulgaris is one of the most widely consumed legumes across the globe. It is rich in protein, carbohydrates, fiber, bioactive compounds, and mineral contents. Occurrences of drought under changing climate have posed a challenge to the quality and quantity of the crop yield. Our study, taking Phaseolus vulgaris as a test legume, reports that as a soil amendment, biochar and farmyard manure mitigated drought-induced damage in the plant. The experiment was set up in a greenhouse with 1 m2 blocks together arranged in factorial randomized block design. Water withdrawal was done for 15 days in either vegetative or reproductive stage of the crop to simulate drought conditions. Biochar or Farmyard manure was applied at the rate of 10t ha−1 as soil amendment and each treatment was replicated thrice. Higher photosynthesis (up to 23% and 16%, respectively), leaf protein (41% and 30%, respectively), grain protein (4% and 19%, correspondingly), and in-vitro protein digestibility (60% and 254%, respectively) were noted under application of both the amendments. Grain quality in terms of protein content, in-vitro protein digestibility, and protein fractions of Phaseolus vulgaris was improved under drought due to the addition of biochar and farmyard manure. However, the application of those amendments at the rate of 10t ha−1, especially farmyard manure, had a negative impact on the antinutritional factor (phytic acid) and mineral bioavailability. Between the two amendments studied, farmyard manure proved to be more efficient in promoting the overall grain quality of P. vulgaris, but its inimical effects must be concorded. [ABSTRACT FROM AUTHOR]

Salinity is a major environmental problem that adversely affects plant growth by increasing soil osmotic pressure and disrupting plant nutrition. Using organic amendments is a viable tool for reducing physiological and morphological effects of excessive soil salinity on plants. To show the impacts of tea waste, compost and biochar on nutrient status and growth parameters of spinach (Spinacia oleracea L.) raised in salinity conditions, this study has employed factorial CRD with two treatments involving soil salinity (2.5 and 8 dS m−1) and organic materials (spent tea waste (STW), spent tea waste compost (STWC) and spent tea waste biochar (STWB)) at 0 and 3% w/w in three replications. As soil salinity increased from 2.5 to 8 dS m−1, fresh weight and dry matter production decreased by 31.5% and 30.4%, respectively. Phosphorous and potassium concentrations in plant tissue also decreased significantly due to the increase in salinity. Organic amendments (except STW) due to their physicochemical properties increased the nutrients uptake and growth parameters of the plant. Compared to other amendments, biochar reduced salinity effects on plant growth more effectively, which is possibly due to its high nutrient adsorbing and water holding capacity. In saline conditions, the highest potassium to sodium ratio belonged to the biochar treatment, which was 3.22 and 2.78 times greater than spent tea waste and compost, respectively. Therefore, it was preferred to change the spent tea waste into biochar before being used as soil amendment. [ABSTRACT FROM AUTHOR]

Background: Cricket feces is a potential high-quality soil amendment, but there is currently no established optimum rate for its application in paddy soils with varying moisture contents. This study therefore aimed to evaluate the effects of varied rates of cricket feces on soil properties, rice growth and yield in paddy soils with differing moisture contents. Methods: Two study factors were evaluated: (i) the maximum water-holding capacity (WHCmax) and flooded soils and (ii) cricket feces applied at rates of 0 (unamended), 3.13 (low), 6.25 (medium) and 12.50 (high) t/ha. Result: The total grain weight of rice in soil with WHCmax was 2.60, 4.33, 6.91 and 7.49 g/hill under the cricket feces from unamended to high rates, respectively, with no significant difference between the medium and high rates. Meanwhile, the total grain weight in flooded soil was 1.85, 4.02, 4.70 and 5.72 g/hill, respectively. Cricket feces increased the content of essential elements and decreased the acidity and toxicity of Al, Ca and Na in the soil, thereby promoting rice growth and yield. The optimal application rates of cricket feces for rice in the WHCmax soil were determined to be the medium rate, while that in flooded soil was the high rate. [ABSTRACT FROM AUTHOR]

Promoting soil suppressiveness against soil borne pathogens could be a promising strategy to manage crop diseases. One way to increase the suppression potential in agricultural soils is via the addition of organic amendments. This microbe-mediated phenomenon, although not fully understood, prompted our study to explore the microbial taxa and functional properties associated with Rhizoctonia solani disease suppression in sugar beet seedlings after amending soil with a keratin-rich waste stream. Soil samples were analyzed using shotgun metagenomics sequencing. Results showed that both amended soils were enriched in bacterial families found in disease suppressive soils before, indicating that the amendment of keratin-rich material can support the transformation into a suppressive soil. On a functional level, genes encoding keratinolytic enzymes were found to be abundant in the keratin-amended samples. Proteins enriched in amended soils were those potentially involved in the production of secondary metabolites/antibiotics, motility, keratin-degradation, and contractile secretion system proteins. We hypothesize these taxa contribute to the amendment-induced suppression effect due to their genomic potential to produce antibiotics, secrete effectors via the contractile secretion system, and degrade oxalate—a potential virulence factor of R. solani —while simultaneously possessing the ability to metabolize keratin. [ABSTRACT FROM AUTHOR]

Soil ameliorants play a crucial role in enhancing soil fertility and rice (Oryza sativa L.) production in acidsulfate soils. This research aims to study the impact of Si-humic ameliorants on soil chemical properties, plant growth, Fe levels, and rice production in acid-sulfate soil. The experiments were conducted at the Laboratory and Greenhouse of the Indonesia Swampland Agricultural Research Institute. The greenhouse experiment adopted a factorial RCBD with Factor 1 representing the ameliorant formula type: 100% lime (F0), 30% commercial humate+30% rice husk ash+40% lime (F1), 30% water hyacinth humate+0% rice husk ash+40% lime (F2), 30% water hyacinth humate+30% rice husk biochar+40% lime (F3), 30% commercial humate+30% rice husk biochar+40% lime (F4), and control without ameliorant. Factor 2 represents dosage of soil ameliorant: 0, 1, 2, and 4 t ha-1. Observations included soil properties such as pH, exchangeable Fe, available P, plant growth, Fe toxicity, yield, and yield components. Silicon-humic soil ameliorant demonstrated the ability to enhance soil pH from 3.16 to 3.63, available P from 6.12 to 30.16 mg kg-1, and decrease Fe 690 to 371 mg kg-1. Specifically, the F3 Si-humate formulation alleviated Fe toxicity, enhanced P availability, promoted rice growth, and improved yield. The application of 4 t ha-1 Sihumate F3 had the best effect in increasing grain yield by 4.22 g pot-1 compared to the control. The application of Si-humate F3 not only improved soil quality and increased rice yields but also reduced the need for lime, contributing to the potential maintenance of soil health. [ABSTRACT FROM AUTHOR]

The residual effect of compost and biochar amendment on soil properties and durum wheat response was evaluated under field conditions in a Mediterranean environment. The treatments compared in a randomized complete block experimental design with three replications were: mineral fertilizer (100 kg N ha−1), compost applied at the rate of 25 Mg ha−1, biochar applied at the rates of 10 and 30 Mg ha−1, unfertilized control. Wheat was the second crop included in a sorghum–wheat cropping system and did not receive fertilizer supply. A hierarchical statistical analysis was carried out to investigate how different treatments could impact the cropping system performance. The findings highlight the significant influence of soil properties, particularly total N, WEOC, and TOC, on wheat and protein yield. One year after the amendment and fertilizer application, compost and biochar significantly increased soil total organic carbon content. The highest soil water extractable organic carbon was found with the compost application (76.9 mg kg−1), whereas the lowest value (50 mg kg−1) was with the highest rate of biochar. Soil respiration rates and hydraulic properties were not affected by the investigated treatments. This behavior is probably related to the short experimental duration and to the silty clayey soil texture. Significant correlations were observed between bulk density and water content at pressure heads in the −20 and −100 cm range; this range accounts for the effect of soil macro and mesopores. Multiple linear regression analysis revealed strong predictive power for grain (R2_adj = 0.78; p < 0.001) and protein yield (R2_adj = 0.77; p < 0.001). The highest grain yield (3.36 Mg ha−1) was observed with compost, and the lowest (2.18 Mg ha−1) with biochar at a rate of 30 Mg ha−1. These findings lay the basis for understanding how different soil amendment management may impact soil quality and wheat performance, even in consideration of climate change. [ABSTRACT FROM AUTHOR]

Soil amendment with biochar from oil palm biomass has been found to improve the quality of the infertile weathered soils and enhance crop productivity in the humid tropics. Meanwhile, the field information on microbial responses to oil palm-derived biochar application and its residual effect in acidic tropical soils is still limited. A field study was carried out over three cropping cycles of sweet corn on a Haplic Acrisol of Peninsular Malaysia. The soil was amended once with oil palm kernel shell (OPKS) biochar before the first cropping cycle, with or without inorganic fertiliser. Soil samples were taken at each harvesting stage and analysed for soil pH, cation exchange capacity (CEC), organic C, total N, available P, microbial biomass (C (MBC), N (MBN), and P (MBP)). Microbial biomass ratios (MBC : MBN, MBC : MBP) were calculated. The total bacterial and fungal populations were quantified from soil genomic DNA, employing qPCR amplification of the 16S rDNA and ITS gene. The sole application of biochar and its combined application with fertiliser, increased soil pH, CEC, organic C and N. Coapplication of OPKS biochar and NPK fertiliser hindered N loss in the second cycle. The bacterial and fungal abundance was stimulated following biochar treatment majorly due to the elevation of soil pH and CEC. The ratio of MBC : MBN had a significant negative correlation with N, signifying that this ratio could reflect soil N content and be used as a soil fertility indicator. [ABSTRACT FROM AUTHOR]

Biochar is widely used as a soil amendment in green roofs because it can increase the soil's water-holding capacity, inhibit cracking, and provide nutrients for vegetation. The interaction mechanism between biochar and expansive soil is a significant factor in the performance of green roofs. However, research mainly focused on the hydrological scale (i.e. runoff regulation and rainwater storage), and there is a lack of research on the hydrological properties (i.e. hysteresis of soil–water characteristic curves, changes in soil pore size and pore distribution, formation and development of cracks and swelling–shrinking characteristics) of biochar-amended expansive soils under dynamic water environment. This test was conducted out on soil columns with expansive soil and 5% (by mass) biochar-amended under 5 drying–wetting cycles. The results showed that within the range of water content suitable for plant growth (i.e. between the anaerobic point and wilting point), the hysteresis area of soil–water characteristic curves of the amended soil is smaller than the bare soil at each drying–wetting cycle. The addition of biochar changes the pore size distribution of the soil, reduces the pore size and swelling–shrinking characteristics of the expansive soil, and inhibits the development of cracks. Therefore, the addition of biochar significantly attenuates the hysteresis characteristics of the soil–water characteristic curves of expansive soils, which may improve the stability of the hydraulic performance of green roofs. The results contribute to the understanding of the physicochemical and water properties of biochar-amended expansive soil and provide theoretical support for the application of biochar to green roofs. [ABSTRACT FROM AUTHOR]

Background: The application of synthetic chemical inputs in current agricultural practices has significantly increased crop production, but their use has caused severe negative consequences on the environment. Humalite is an organic soil amendment that is rich in humic acid and found in large deposits in southern Alberta, Canada. Humic products can enhance nutrient uptake and assimilation in plants by reducing nutrient losses and enhancing bioavailability in the soil. Aim: Here, we evaluated the effects of different humalite rates in the presence of nitrogen, phosphorus, potassium (NPK) at recommended rates on soil nitrogen availability, wheat growth, grain yield, seed nutritional quality, and nitrogen use efficiency (NUE) under controlled environmental conditions. Methods: A series of studies were conducted by applying five different rates of humalite (0, 200, 400, 800, and 1600 kg ha−1) with NPK at recommended rates. Soil nitrogen availability and shoot and root growth parameters were recorded at flowering stage. NUE was calculated based on the grain yield at maturity stage. Results: Plants grown in the presence of humalite augmented root morphological parameters (root length, volume, and surface area), plant biomass (shoot and root), and nutrient uptake (N, P, K, and S) compared to the plants supplied with recommended fertilizer alone. Furthermore, humalite application significantly increased grain yield (14%–19%), seed protein content (23%–30%), and NUE (14%–60%) compared to the fertilizer application alone. Conclusion: These findings suggest that humalite can be used as an organic soil amendment to reduce synthetic fertilizer application and improve plant growth and yield while enhancing fertilizer use efficiency. [ABSTRACT FROM AUTHOR]

Background and Aims: The use of organic amendments improves soil functioning and thus crop productivity. Our previous studies have shown that the banding of organic amendments increases the transpiration efficiency (TE) of wheat plants, but the underlying mechanism remained unclear. This study aims to determine whether and how the organic amendments can increase the TE of corn plants (Zea mays L.). Methods: The effects of nutrient-enriched poultry litter, compost and brown coal on TE were compared with inorganic fertilizer. Corn plants were grown in Chromosol topsoil in pots for 50 days. Results: The poultry litter and compost but not brown coal, increased the TE of corn plants by 25% and 14%, respectively (P < 0.05), compared to inorganic fertilizer. At the leaf level, poultry litter and compost also increased the instantaneous TE due to either decreased transpiration or increased instantaneous CO2 assimilation rates. The increased TE at the plant level was closely associated with increased abundances of soil fungi, bacteria and bacteria in genus Bacillus. Meanwhile, there were increases in the concentrations of leaf hormones abscisic acid (ABA) (> 50%), methyl jasmonate (JA) (> 80%) and indole acetic acid (IAA). Conclusion: Organic amendments enhanced the population of plant beneficial soil microorganisms such as those in the Bacillus genus, which likely led to the increased biosynthesis of leaf hormones ABA and JA, resulting in stomatal close, reduced total transpiration and increased transpiration efficiency of the corn canopy. [ABSTRACT FROM AUTHOR]

Purpose: Revegetation of bauxite residue disposal areas is an effective disposal strategy for large-scale in-situ disposal and reduction of environmental risk. The application of organic amendments is an effective method of increasing the organic carbon content of residue. Humification of bauxite residue by different types of organic amendments in the synergistic effect of Ca-containing solid waste was investigated. Methods: 100-day incubation experiments using Fourier Transform Infrared Spectroscopy (FTIR), Excitation-Emission Matrix (EEM) fluorescence, Ultraviolet–Visible (UV–Vis) spectroscopy, Illumina high-throughput sequencing technology for the analysis of bauxite residue treated with different organic amendments. The organic amendments treatments applied included corn straw (BGS), nitrohumic acid (BGH), and poultry manure (BGM), and the pretreated residue (desulphurization gypsum mixed with bauxite residue) was the BG. Results: The composition and parameters of humic substances of bauxite residues with different treatments was ranked as BG < BGM < BGS < BGH. BGS treatment has the highest humification rate. For carbon cycle-related enzymes, enzyme activities of corn straw treatment were higher, indicating that straw addition was more intense on carbon turnover. Combined with microbial activity, the manure had sufficient nutrients, which was conducive to microbial growth and reproduction. Redundancy analysis (RDA) and two-factor correlation network showed that microorganisms influence humification characteristics by secreting carbon cycle-related enzymes. Conclusions: The nitrohumic acid treatment had a higher humification degree but limited microbial activity, whilst corn straw treatment had a wide potential for humification and enzyme activity. Desulfurization gypsum and corn straw have novel application prospects on ecological rehabilitation at disposal areas. Highlights: The effects of different organic amendments in bauxite residue from two dimensions of humification and microbial activity were evaluated. Organic amendments significantly changed the humification characteristics of the residues in both solid and liquid phases. Corn straw addition was more intense on enzymes related to carbon cycle and has a wide humification potential in bauxite residue. Desulfurization gypsum and corn straw have novel application prospects on ecological rehabilitation at disposal areas. [ABSTRACT FROM AUTHOR]

Optimizing beneficial plant–microbe interactions can significantly enhance plant growth and resilience, which may be achievable through a targeted step-by-step process using customized microbiome engineering. 'Plant/microbe-friendly' soils can be prepared through traditional and targeted soil amendments to increase microbial diversity and soil fertility to suit specific plant cultivation needs. 'Microbe-friendly' plants and genotypes should be chosen because different crops and varieties vastly differ in their ability to benefit from microbes. 'Plant-friendly' microbiomes can be generated by applying suitable functional microbial inoculants with optimal formulations and supportive substrates. Microbiome breeding, microbiome transplanting, and the use of artificial microbial consortia to fill microbiome functional deficiencies are promising emerging areas that warrant further validation. Plant microbiomes play a vital role in promoting plant growth and resilience to cope with environmental stresses. Plant microbiome engineering holds significant promise to increase crop yields, but there is uncertainty about how this can best be achieved. We propose a step-by-step approach involving customized direct and indirect methods to condition soils and to match plants and microbiomes. Although three approaches, namely the development of (i) 'plant- and microbe-friendly' soils, (ii) 'microbe-friendly' plants, and (iii) 'plant-friendly' microbiomes, have been successfully tested in isolation, we propose that the combination of all three may lead to a step-change towards higher and more stable crop yields. This review aims to provide knowledge, future directions, and practical guidance to achieve this goal via customized plant microbiome engineering. Plant microbiomes play a vital role in promoting plant growth and resilience to cope with environmental stresses. Plant microbiome engineering holds significant promise to increase crop yields, but there is uncertainty about how this can best be achieved. We propose a step-by-step approach involving customized direct and indirect methods to condition soils and to match plants and microbiomes. Although three approaches, namely the development of (i) 'plant- and/or microbe-friendly' soils, (ii) 'microbe-friendly' plants, and (iii) 'plant-friendly' microbiomes, have been successfully tested in isolation, we propose that the combination of all three may lead to a step-change towards higher and more stable crop yields. This review aims to provide knowledge, future directions, and practical guidance to achieve this goal via customized plant microbiome engineering. [ABSTRACT FROM AUTHOR]

Recycling of phosphorus (P) from feedstocks to soils can provide sustainability in agriculture. In our incubation study, we investigated the effects of adding cow manure-derived vermicompost (CMV), cow manure (CM), sugarcane trash biochar (STB), and triple super phosphate (TSP) to extractable P in a sandy loam soil. P was added to the soil at rates of 0, 50, 100, 200, and 300 mg kg−1 based on their total P contents. The amended soils were incubated for 1, 4, 8, and 16 weeks (wk) at room temperature and extractable P samples were measured (by water, Olsen, Mehlich-3 and Bray and Kurtz) and soil pH was monitored. After 1 wk of incubation, the extractable P values were 1.4 mg kg−1 with STB at the smallest while the highest was 79 mg kg−1 with TSP. The corresponding P values in the CMV and CM amended soils were 33 mg kg−1 and 31 mg kg−1. The reductions of extractable P from 1 to 16 wks of incubation were 40%, 35%, and 80% in the CMV, CM and TSP amended soils, respectively, while they increased from 1.43 mg kg−1 to 6.05 mg kg−1 ((320%) in the STB amended soil. Among the amendments, a significant positive relationship was observed between extractable P and the pH in soils amended with STB. The findings revealed that varying P extractability in soils depends on amendment types and duration of incubation. Sugarcane trash biochar did not exhibit an ability to substitute inorganic P fertilizer for assessing bioavailable P. [ABSTRACT FROM AUTHOR]

Agroecology is gaining increased attention by experts and global organizations; however, it's practical application in the field remains understudied, particularly in developing countries. Here, we aimed to evaluate common agroecological practices at three sites in Tanzania, including organic soil amendments, intercropping, and biological pest control – individually, in pairs, or in three-way combinations at each site. Information Communication Technology tools – the AgroEco Research and AgroEco Analysis application – were used for data gathering & storage and data visualization & statistical analysis, respectively. We found that high maize kernel weights (as proxy for yield) can be obtained from nutrient-poor soils specifically when grown with a combination of organic soil amendments and intercropped with legumes – ranging from 3 to 4.5 t/ha (with a maximum of 7 t/ha on one occasion) and exceeding national maize yields of 1–2 t/ha in Tanzania. However, intercropping and biological pest control individually and in combination did not affect maize yield. Under flood or drought conditions, only plots with soil fertility amendments produced some harvestable maize kernels. Our results provide a substantial reference for recommending and advocating agroecological methods to smallholder farmers, farmer training organizations, and policy makers. [ABSTRACT FROM AUTHOR]

Bioretention systems use plants and soil media to treat pollutants in stormwater. Biochar can be an effective amendment to bioretention soil media for removing pollutants due to its adsorption properties. This study evaluates biochar as an amendment to bioretention soil media for the removal of contaminants in stormwater. Columns with varying ratios of biochar to bioretention soil media (0%, 25%, and 50% biochar) were tested to evaluate the removal efficiencies of copper, zinc, phosphorus, nitrogen, and microplastics from stormwater. Five trials were conducted with stormwater collected from parking lot runoff. Results show that the addition of biochar in bioretention systems improves the removal efficiency of zinc (average of 79% in columns with 50% biochar compared to 54% in columns without biochar) and copper (average of 73% in columns with 50% biochar compared to 25% in columns without biochar). Stormwater effluent from the biochar-amended columns also had significantly lower turbidity (21 NTU) than that of the control columns (58 NTU). Consistent leaching of nitrogen and phosphorus species was evident in the control as well as the biochar-amended columns, with average removal efficiencies of −1,114% for total nitrogen and −703% for total phosphorus. Microplastics were effectively removed by all columns, regardless of biochar amendment, with an average removal of 86%. This study indicates that biochar has the potential to reduce metal concentrations in stormwater when used as an amendment to bioretention systems but has a limited impact on nutrients and microplastics. [ABSTRACT FROM AUTHOR]

Biochar is widely used as a good soil amendment, while knowledge of modified biochar application in tea garden soils contaminated by fluoride (F) and cadmium (Cd) is insufficient. The tea seedling (Camellia sinensis L.) growth assay was performed to evaluate interaction of soil Cd and F and the improving effect of aluminum trichloride-modified corn stalk biochar (Al-BC) on their speciation, phytoaccumulation and phytotoxicity. Results showed that soil F speciation ratio sequence was as follows: residual > exchangeable > organic-bound > water-soluble > Fe/Mn oxide-bound. Soil exchangeable Cd was the largest Cd speciation (>35.6%), probably due to the low pH values in the acid tea gardens. Root F contents showed a strong significant relationship with soluble F contents (r = 0.92, P <.01) and similarly root Cd highly connected with exchangeable Cd (r = 0.86, P <.01). Seedling height, fresh and dry weight, root surface area, length, and photosynthetic pigment showed different sensitivities to F or Cd oxidative stress and toxicity effects, and only root F contents significantly inversely correlated with them (r = 0.74–0.80, P <.01). The interaction of Cd and F, could influence their speciation distribution and antagonized each other in root accumulation. Meanwhile, joint simulation models showed that antagonistic effects were observed in the F and Cd mixture soils for most cases at Enshi. Biochar application reduced bioavailable F and Cd contents, and thus decreased F and Cd accumulation in tea roots and obviously alleviated toxicity effects. For instance, biochar application significantly reduced root F contents, which had 33.2% to 62.2% declines at Enshi and 39.7% to 77.2% declines at Huanggang. Meanwhile, the soil properties were improved as biochar added, with an increase in soil pH, EC, CEC and organic matter. Overall, Al-modified biochar was beneficial environmental materials for reducing both F and Cd bioavailability. [ABSTRACT FROM AUTHOR]

The dissemination of antibiotic resistance genes (ARGs) in soil has become a global environmental issue. Vermicomposting is gaining prominence in agricultural practices as a soil amendment to improve soil quality. However, its impact on soil ARGs remains unclear when it occurs in farmland. We comprehensively explored the evolution and fate of ARGs and their hosts in the field soil profiles under vermicompost application for more than 3 years. Vermicompost application increased several ARG loads in soil environment but decreased the high-risk bla -ARGs (bla ampC , bla NDM , and bla GES-1) by log(0.04 – 0.43). ARGs in soil amended with vermicompost primarily occurred in topsoil (approximately 1.04-fold of unfertilized soil), but it is worth noting that their levels in the 40–60 cm soil layer were the same or even less than in the unfertilized soil. The microbial community structure changed in soil profiles after vermicompost application. Vermicompost application altered the microbial community structure in soil profiles, showing that the dominant bacteria (i.e., Proteobacteria, Actinobacteriota, Firmicutes) were decreased 2.62%–5.48% with the increase of soil depth. A network analysis further revealed that most of ARG dominant host bacteria did not migrate from surface soil to deep soil. In particular, those host bacteria harboring high-risk bla -ARGs were primarily concentrated in the surface soil. This study highlights a lower risk of the propagation of ARGs caused by vermicompost application and provides a novel approach to reduce and relieve the dissemination of ARGs derived from animals in agricultural production. [Display omitted] [ABSTRACT FROM AUTHOR]

An initial investigation into the utilization of recycled plant and animal residues as soil amendments (SAs), including compost, biochar, and soil conditioner, was conducted using alfalfa crops. This study evaluated the impact of SAs on alfalfa seed germination, resulting in an 87% germination rate for biochar, 82% for soil conditioner, and 82% for compost. In comparison, untreated seeds displayed a 78% germination rate. After successful germination, the SAs were employed to enhance soil health, with a focus on water conservation and increased forage yield. The study used sandy-textured soil with moderate alkalinity, very slight salinity, slight calcareousness, and high permeability. The germination trial confirmed that SAs usage did not hinder seed germination, even for salt-sensitive crops like alfalfa. Two field experiments were carried out in Al-Wafra, using different application rates of compost, biochar, and soil conditioner at 5, 7.5, and 10 tons per hectare. The results highlighted the positive impact of SAs application on increasing forage production, with varying degrees of enhancement, and confirmed a 40% reduction in water usage compared to treatment without SAs but under 100% irrigation (100% ETc). In conclusion, SAs show promising potential for local forages intensification and water conservation. [ABSTRACT FROM AUTHOR]

BACKGROUND: The accumulation of microplastics in agricultural soil poses a threat to the sustainability of agriculture, impacting crop growth and soil health. Due to the geocarpy feature of peanut, geocarposphere soil environment is critical to pod development and its nutritional quality. While the effects of microplastics in the rhizosphere have been studied, their impact on peanut pod in the geocarposphere remains unknown. Biochar has emerged as a potential soil agent with the ability to remediate soil contamination. However, the mechanisms of biochar in mitigating the toxic effects of microplastics-contaminated geocarposphere soil on peanut pod development remain largely unexplored. RESULTS: We evaluated the peanut pod performance and microbiome when facing microplastics contamination and biochar amendment in geocarposphere soil. The results showed that microplastics present in geocarposphere soil could directly enter the peanut pod, cause pod developmental disorder and exert adverse effects on nutritional quality. Aberrant expression of key genes associated with amino acid metabolism, lipid synthesis, and auxin and ethylene signaling pathways were the underlying molecular mechanisms of microplastics-induced peanut pod developmental inhibition. However, these expression abnormalities could be reversed by biochar application. In addition, peanut geocarposphere microbiome results showed that biochar application could restore the diversity of microbial communities inhibited by microplastics contamination and promote the relative abundance of bacteria correlated with pathogen resistance and nitrogen cycle of geocarposphere soil, further promoting peanut pod development. CONCLUSION: This study demonstrated that biochar application is an effective strategy to mitigate the toxic effects of microplastics-contaminated geocarposphere soil on pod development and nutritional quality. [ABSTRACT FROM AUTHOR]

Thin layer sediment placement (TLP) is used to build elevation in marshes, counteracting effects of subsidence and sea level rise. However, TLP success may vary due to plant stress associated with reductions in nutrient availability and hydrologic flushing or through the creation of acid sulfate soils. This study examined the influence of sediment grain size and soil amendments on plant growth, soil and porewater characteristics, and greenhouse gas exchange for three key U.S. salt marsh plants: Spartina alterniflora (synonym Sporobolus alterniflorus), Spartina patens (synonym Sporobolus pumilus), and Salicornia pacifica. We found that bioavailable nitrogen concentrations (measured as extractable NH4+‐N) and porewater pH and salinity were inversely related to grain size, while soil redox was more reducing in finer sediments. This suggests that utilizing finer sediments in TLP projects will result in a more reduced environment with higher nutrient availability, while larger grain sized sediments will be better flushed and oxygenated. We further found that grain size had a significant effect on vegetation biomass allocation and rates of gas exchange, although these effects were species‐specific. We found that soil amendments (biochar and compost) did not subsidize plant growth but were associated with increases in soil respiration and methane emissions. Biochar amendments were additionally ineffective in ameliorating acid sulfate conditions. This study uncovers complex interactions between sediment type and vegetation, emphasizing the limitations of soil amendments. The findings aid restoration project managers in making informed decisions regarding sediment type, target vegetation, and soil amendments for successful TLP projects. [ABSTRACT FROM AUTHOR]

Important properties of biochar as an effective soil amendment are its high water-holding capacity (WHC) and inhibition of water evaporation. However, the mechanism and the importance of biochar properties in controlling its own WHC and bound water evaporation remain little known. In this study, wheat straw and pine sawdust biochars were pyrolyzed in N2-flow, CO2-flow, and air-limitation environments at 300–750 ℃, and a series of the produced biochars' properties were characterized to explore the dominant controlling factors of their WHC and bound water evaporation. The results have shown that with the increasing contents of hydrogen, nitrogen, and oxygen as well as such ratios as H/C, and (O + N)/C, WHC of the biochars was also increasing while the evaporation of biochar-bound water was decreasing. With an increase in the other studied factors, such as carbon content, pH, and specific surface area (SSA), WHC of the biochars was decreasing, and the evaporation of biochar-bound water was increasing. That was connected with the fact that biochar-nitrogen was mainly in pyridinic and pyrrolic forms, while oxygen was in the form of C = O and C–O bonds. These forms of nitrogen and oxygen could be the receptors of hydrogen bonds to link to H2O molecules. Aliphatic hydrogen with a weak positive charge could be a donor of hydrogen bonds to link to H2O molecules. However, high carbon content, as well as high SSA, indicated more exposed aromatic carbon (hydrophobic sites) that could suppress the binding of H2O molecules. Additionally, high pH indicated that H2O molecules were dominated by OH–, which generated strong electrostatic repulsion with the negatively charged nitrogen- and oxygen-containing groups of biochar. It was also shown that the nitrogen-containing groups played a more important role (importance – 0.31) in WHC of the biochar than other parameters, including carbon, oxygen, hydrogen, ash contents, pH, SSA (importance from 0.02 to 0.09). Nitrogen, oxygen, and carbon contents had the most important influence on the evaporation of biochar-bound water in all studied factors. Furthermore, wheat straw biochar produced at low pyrolysis temperatures in N2 atmosphere (with high nitrogen and oxygen contents) had the highest WHC and the lowest evaporation of biochar-bound water. Consequently, it can be suggested that biochar rich in nitrogen can be an effective water retention agent and can improve agricultural soil moisture. Highlights: Nitrogen-containing groups (pyridinic and pyrrolic nitrogen) played a crucial role in the improvement of biochar water-holding capacity. Nitrogen- and oxygen-containing groups inhibited the evaporation of biochar-bound water. Biochar rich in nitrogen and oxygen may be an effective water retention agent to maintain soil moisture. [ABSTRACT FROM AUTHOR]

In response to the environmental concerns posed by cadmium (Cd) contamination, the application of nano‐submicron mineral‐based soil conditioner (MSC) as a potential soil amendment has garnered interest due to its promising Cd mitigation properties. In this study, we aimed to investigate the solidification capacity and mechanism of Cd in MSC and examine the phase and morphology changes following solidification. Systematic experiments were conducted to assess the solidification capacity of MSC for Cd, revealing an impressive efficiency of nearly 100 % even at Cd concentrations of approximately 800 mg/L. The solidification efficiency was found to be positively correlated with the pH value, significantly declining as the environment shifted from pH>7 to pH<7. Notably, under alkaline conditions (pH>7), Cd solidification in MSC was primarily attributed to the Cd‐OH complex formed on the surface of MSC and aided by cation‐exchange reaction. In contrast, under acidic conditions (pH<7) and exposure to extreme Cd concentrations, Cd(OH)Cl precipitation became the dominant mechanism for solidification. Interestingly, the presence of KCdCl3, a water‐soluble phase, did not significantly contribute to the overall solidification efficiency. These findings provide valuable insights into the solidification mechanism of Cd in MSC and offer potential implications for soil remediation efforts targeting Cd contamination. [ABSTRACT FROM AUTHOR]

Globally, salinity is an important abiotic stress in agriculture. It induced oxidative stress and nutritional imbalance in plants, resulting in poor crop productivity. Applying silicon (Si) can improve the uptake of macronutrients. On the other hand, using biochar as a soil amendment can also decrease salinity stress due to its high porosity, cation exchange capacity, and water-holding capacity. That's why the current experiment was conducted with novelty to explore the impact of silicon nanoparticle-based biochar (Si-BC) on wheat cultivated on salt-affected soil. There were 3 levels of Si-BC, i.e., control (0), 1% Si-BC1, and 2.5% Si-BC2 applied in 3 replicates under 0 and 200 mM NaCl following a completely randomized design. Results showed that treatment 2.5% Si-BC2 performed significantly better for the enhancement in shoot and root length, shoot and root fresh weight, shoot and root dry weight, number of leaves, number of tillers, number of spikelets, spike length, spike fresh and dry weight compared to control under no stress and salinity stress (200 mM NaCl). A significant enhancement in chlorophyll a (~ 18%), chlorophyll b (~ 22%), total chlorophyll (~ 20%), carotenoid (~ 60%), relative water contents (~ 58%) also signified the effectiveness of treatment 2.5% Si-BC2 than control under 200 mM NaCl. In conclusion, treatment 2.5% Si-BC2 can potentially mitigate the salinity stress in wheat by regulating antioxidants and improving N, K concentration, and gas exchange attributes while decreasing Na and Cl concentration and electrolyte leakage. More investigations at the field level are recommended for the declaration of treatment 2.5% Si-BC2 as the best amendment for alleviating salinity stress in different crops under variable climatic conditions. [ABSTRACT FROM AUTHOR]

The land application of sewage sludge can cause different environmental problems due to the high content of potentially toxic elements (PTEs). The objective of this study was to compare the effect of urban biological sewage sludge (i.e. the waste of activated sludge process) and its derived biochar as the soil amendments on the bioavailability of PTEs and their bioaccumulation by corn (Zea mays L.) under two months of greenhouse conditions. The soil was treated by adding biochar samples at 0 (control), 1, 3, 5% w/w. The diethylenetriamine pentaacetic acid (DTPA)-extractable concentrations of PTEs including Zn, Pb, Cd, Cr, Ni, Fe, and Cu in soil and their accumulation by plant shoot and root were measured. Conversion of the biological sewage sludge into the biochar led to decrease the PTEs bioavailability and consequently decreased their contents in plant tissues. The DTPA extractable metal concentrations of produced biochar in comparison to the biological sewage sludge reduced 75% (Cd), 65% (Cr), 79% (Ni and Pb), 76% (Zn), 91% (Cu) and 88% (Fe). Therefore, the content of Ni, Fe, Zn and Cd in corn shoot was decreased 61, 32, 18 and 17% respectively in application of 5% biochar than of raw sewage sludge. Furthermore, the application of 5% biochar enhanced the physiological parameters of the plants including shoot dry weight (twice) and wet weight (2.25 times), stem diameter (1.70 times), chlorophyll content (1.03 times) in comparison to using 5% raw sewage sludge. The results of the study highlight that application of the biochar derived from urban biological sewage sludge in soil could decrease the risk of PTEs to the plant. [ABSTRACT FROM AUTHOR]

It has been proposed that the quality of acidic soils can be improved in the presence of alkaline byproduct amendments containing silicon (Si), calcium (Ca), magnesium (Mg), and potassium (K). In the present study, we aimed to explore the effect of byproduct amendments on ameliorating acidic soil in Jiaodong Peninsula of China in the existence of different types of low-molecular-weight organic acids (LOAs, such as malic acid, citric acid, oxalic acid, and succinic acid) that are usually excreted by plant roots. Therefore, a 60-day incubation test was carried out to assess the effect of byproduct amendments and LOAs on soil physicochemical properties, soil available Mg and Ca, cation exchange capacity (CEC), soil respiration, and enzyme activities. The results showed that in the presence of LOAs, the byproduct amendments could still increased the soil pH and decreased the soil exchangeable acid and exchangeable Al3+. Compared with the control group (CK), all byproduct amendment-containing treatments could increase soil available Mg and Ca, soil CEC, soil respiration, and soil sucrase (S-SC) activity. The addition of byproduct amendments could significantly improve the chemical and biological properties of the acidic brown soils in Jiaodong Peninsula of China. However, LOAs, especially the LOAs that could precipitate with Ca in byproduct amendments, negatively impair the ameliorating effect on acidic soil compared with byproduct amendments alone treatment. When using byproduct amendments to ameliorate acidic soil, the type of LOAs secreted by plant roots was an influencing factor that must be considered. [ABSTRACT FROM AUTHOR]

Soil application of treated sewage sludge is considered a beneficial management option for agriculture and environment. Sludge treated with clay minerals or biochar was evaluated as soil amendment, in comparison with limed or untreated sludge. Bentonite, vermiculite, biochar or lime was added to dewatered sewage sludge at 0 and 15% rates, in three replications and air-dried. Then, the treated and untreated sludge were added to two soils, one acid and one alkaline, at 0 (control), 1 and 3% rates, in three replications. The results showed that the pH of acid soil significantly increased compared to control upon addition of treated and untreated sludge at both rates, but remained acidic (<6.0) in all cases except for limed sludge. Upon addition of 3% treated or untreated sludge to both soils, organic carbon (OC) significantly increased compared to control. The same stands for soil available ammonium nitrogen (NH4-N), phosphorus (P), potassium (K), copper (Cu), zinc (Zn) and boron (B) for both soils and rates. Soil total heavy metals, which regulate sludge's agronomic use, were below the legislative limits. However, the 3% addition rate of all kinds of sludge, especially of untreated, to both soils increased the electrical conductivity of saturation extract (ECse >2 dS m−1) at unacceptable levels for sensitive crops and available P, B and Zn 2–3, 2–4 and 6–12 times above the initial, respectively. Consequently, sewage sludge treated with bentonite, vermiculite or biochar could be used as a soil amendment but at rates lower than 3% (≈120 Mg ha−1). [ABSTRACT FROM AUTHOR]

Applications of fresh and composted Cotton Gin Byproducts (CGB) and cattle manure as soil amendments are very common practices in the industry. However, composting and direct application of the materials are often limited by factors such as bulkiness, varying nutrient composition and application rates, and handling/transportation costs. This study was conducted to characterize fresh and composted CGB and beef manure (BM) for subsequent co-pelletization and utilization as soil amendments, and to investigate the effects of composting on the nutrient composition and agronomic values. Raw and composted samples of CGB and BM at different storage periods and composting ages were sourced from two commercial gins and a beef farm. Nutrient content, acidity, and compost maturity indices such as carbon/nitrogen (C/N) and ammonium/nitrate (NH4-N/NO3-N) ratios were determined and compared. All samples were obtained at four sampling points on the respective storage or composting piles. The results showed that composted CGB generally contained at least 55% more total-N and phosphorus oxide (P2O5), but approximately 35% less potassium oxide (K2O) than fresh CGB. Composted BM had approximately 3% less total-N, but at least 25% more P2O5 than raw BM. The nutrient compositions affirm the potential for co-pelletizing both forms of CGB and BM to improve the agronomic values and enhance the utilization as soil amendments. In addition, establishing the various properties of CGB and BM is crucial for determining product formulations and selecting process parameters for co-pelletization. [ABSTRACT FROM AUTHOR]

Biochar has been recently proposed as a management strategy to improve crop productivity and global warming mitigation. Biochar may be added to soils with the goal to improve the soil properties and relocate an amount of conventional fossil fuel based fertilizers and sequester carbon. Biochar production and incorporation in soil must play a role in climate change mitigation. The need for further clarity on optimizing biochar application to various crop yields is necessary if it is to gain widespread acceptance as a soil amendment. There is urgent need to intensify agricultural production to secure food supply for the ever increasing population especially in developing country like India of the tropics. Biochar proponents have placed on biochar stability in soil and it also includes increased soil fertility and water holding capacity, increased crop production and remediation of contaminated soils. The biochar have potential to feasibly and sustainably sequester/offset over 1 Pg of CO2-carbon equivalents annually. Current carbon market incentives are not sufficient to rapidly increase or maximize the initiation and development of biochar implementation. [ABSTRACT FROM AUTHOR]

The central part of the country in the world classified Maize as their staple and essential crop, but this crop cannot cultivate appropriately in acidic soil. Thus, biochar, silicon and phosphorus observation can act as an agent to improve the growth of Maize in acidic soil. Additionally, biochar, well known for its alkaline properties, can reduce soil acidification and, at the same time, improve crop production. This low pH condition was caused by aluminium, manganese and low of phosphorus. Thus, silicon and phosphorus can improve crop productivity. Using biochar as a soil amendment raises the pH value, alone or in combination. Maize (Zea mays L.) and the acidity of the soil are much related to the application of biochar combined with silicon and phosphorus. Biochar simply can reduce exchangeable soil acidity, but when combined with silicon and phosphorus, it can have a greater influence on reducing soil Al toxicity. The importance of biochar with different rates combined with silicon and phosphorus to increase the pH of soil is still an inconsistent result by various studies. This review summarizes the properties of biochar, silicon and phosphorus and provides the scientific reference for its application to archive high yield of maize and reduce the acidification effect on soil. [ABSTRACT FROM AUTHOR]

Reducing fertilizer doses under sustainable agricultural management is possible by increasing nutrient utilization efficiency, which will decrease crop production costs and boost economic return. Soil amendments known as water retention agents (WRAs) are added to the soil to enhance crop growth conditions. We hypothesize that the addition of WRAs may support the soil-retaining nutrients given through fertilization and prevent them from leaching into tropical soils characterized by severe rainfall due to WRAs' exceptional capacities to absorb and store water. Mango trees (Mangifera indica L. cv Tainong No. 1) aged 18 years were fertilized with 100% or 80% of the recommended doses of nitrogen (N), phosphorus (P), and potassium (K). The experimental design included three treatments, i.e., complete recommended doses of N, P, and K (CRF), 80% of the complete recommended doses (RRF), and water-retaining agent (40 kg ha−1) + 80% of the complete recommended doses (WRARRF). Reducing the fertilization doses by 20% for mango trees in the studied tropical soil significantly (p < 0.05) minimized the nutrient availability in the soil compared to the complete fertilization doses. WRARRF compensated for the nutrient reduction by increasing the availability of N, P, and K. The addition of WRARR increased N, P, and K in mango leaf by 11%, 4%, and 7% in the first year and by 11%, 6%, and 7% in the second year, respectively, compared to CRF. The addition of WRARR increased the partial fertilizer productivity (PFP) value by 36% and 41% in the first and second years, respectively. The highest mango fruit output was achieved by the addition of WRARRF, which resulted in increases in mango fruit yield of 11.9% and 16.5% in the first and second years, respectively, compared to RRF. Fruit quality traits showed the descending order: WRARRF > RRF > CRF. WRARRF produced the maximum economic benefit (USD 7372 per hectare) compared to CRF and RRF. The polyacrylamide/attapulgite water-retaining agent exhibited remarkable improvement in mango fruit yield and economic profit by regulating the release of nutrients in tropical soils. Water-retaining agents are an effective strategy for overcoming the extensive fertilization used in mango orchards, which has resulted in numerous environmental contaminations and the inefficient use of fertilizers. [ABSTRACT FROM AUTHOR]

Biochar and plant growth-promoting rhizobacteria (PGPR) are widely used as an amendment for soil physicochemical properties and soil bacterial community diversity. In Guangxi, China, we carried out a study to determine how PGPR and biochar influence the soil's environmental stability in an Eucalypt plantation. We applied biochar and PGPR in a contrasting application manner to an acidic red loam soil. Thus, three treatments were set up as 5 × 1010 CFU·mL−1 PGPR-only (MB0), 20 t·hm−2 biochar-only (B20), and co-application of 20 t·hm−2 biochar and 5 × 1010 CFU·mL−1 PGPR (MB20), as well as no biochar and no PGPR (M0B0). Our results indicated that MB20 significantly decreased the soil total nitrogen (TN) and increased the soil total phosphorus (Soil TP), soil ammonium nitrogen (NH4+), and soil water content (SWC) when compared with the control. The MB20 also significantly increased the Simpson, ACE, and Chao indices of the soil bacterial community's diversity relative to the control. We also observed a significant effect of the Soil TN on both the bacterial community and the functional diversity in soil. These findings may indicate that assessing the soil N status is expected to be an essential indicator of the soil microenvironment's response to biochar and PGPR applications. [ABSTRACT FROM AUTHOR]

Common scab is a disease caused by Streptomyces spp. that can significantly reduce potato crop yield and quality, affecting marketability. Traditionally, pesticides have been used to prevent this disease, but this approach has several drawbacks, including the development of pesticide resistance and negative effects on the environment and human health. Therefore, it was essential to develop eco-friendly Integrated Disease Management (IDM) strategies for common scab management. In this study, we evaluated 13 different treatments in various combinations with three replications each. We found that treatment T2 (soil amendments with gypsum at 2.0 t/ha + tuber treatments with Trichoderma harzianum at 5 g/kg + foliar spray of copper oxychloride with streptocycline in a 3:1 ratio) showed the highest reduction in disease severity (3.63%) and incidence (1.79%) compared to the control (46.60% and 34.57%, respectively). Moreover, IDM practices also altered the physiochemical properties of the soil. T2 treatment resulted in the highest pH value of 5.86 after planting and 5.30 after harvesting, with the minimum Electrical Conductivity (EC) value estimated to be 0.089 S/m after planting and 0.087 S/m after harvesting. After planting, T2 treatment showed a soil content of 2.12 mg/kg zinc, 3.41 mg/kg copper, and 38.83 mg/kg iron, which increased to 2.42 mg/kg zinc, 3.27 mg/kg copper, and 38.39 mg/kg iron after harvesting. T4 treatment (soil amendments with elemental sulphur at 0.5 t/ha + tuber treatments with T. harzianum at 5 g/kg + foliar spray of copper oxychloride with streptocycline in a 3:1 ratio) showed the highest sulphur content, estimated at 47.69 mg/kg after planting and 48.43 mg/kg after harvesting, and reduced the disease severity and incidence by 10.89% and 7.19%, respectively. T3 treatment (MnSO4 at 15 kg/ha + T. harzianum at 5 g/kg + copper oxychloride with streptocycline in a 3:1 ratio) resulted in the highest soil content of manganese, with 96.47 mg/kg after planting and 98.84 mg/kg after harvesting. Overall, T2 treatment showed the most effective control against common scab disease and is recommended as the best IDM strategy for potato common scab management. [ABSTRACT FROM AUTHOR]

Precision agriculture (PA) intends to validate technological tools that capture soil and crop spatial variability, which constitute the basis for the establishment of differentiated management zones (MZs). Soil apparent electrical conductivity (ECa) sensors are commonly used to survey soil spatial variability. It is essential for surveys to have temporal stability to ensure correct medium- and long-term decisions. The aim of this study was to assess the temporal stability of MZ patterns using different types of ECa sensors, namely an ECa contact-type sensor (Veris 2000 XA, Veris Technologies, Salina, KS, USA) and an electromagnetic induction sensor (EM-38, Geonics Ltd., Mississauga, ON, Canada). These sensors were used in four fields of dryland pastures in the Alentejo region of Portugal. The first survey was carried out in October 2018, and the second was carried out in September 2020. Data processing involved synchronizing the geographic coordinates obtained using the two types of sensors in each location and establishing MZs based on a geostatistical analysis of elevation and ECa data. Although the basic technologies have different principles (contact versus non-contact sensors), the surveys were carried out at different soil moisture conditions and were temporarily separated (about 2 years); the ECa measurements showed statistically significant correlations in all experimental fields (correlation coefficients between 0.449 and 0.618), which were reflected in the spatially stable patterns of the MZ maps (averaging 52% of the total area across the four experimental fields). These results provide perspectives for future developments, which will need to occur in the creation of algorithms that allow the spatial variability and temporal stability of ECa to be validated through smart soil sampling and analysis to generate recommendations for sustained soil amendment or fertilization. [ABSTRACT FROM AUTHOR]

Drip irrigation with brackish water increases the risk of soil salinization while alleviating water shortage in arid areas. In order to alleviate soil salinity stress on crops, polymer soil amendments are increasingly used. But the regulation mechanism of a polymer soil amendment composed of polyacrylamide polyvinyl alcohol, and manganese sulfate (PPM) on rapeseed photosynthesis under drip irrigation with different types of brackish water is still unclear. In this field study, PPM was applied to study the responses of the rapeseed (Brassica napus L.) phenotype, photosynthetic physiology, transcriptomics, and metabolomics at the peak flowering stage under drip irrigation with water containing 6 g·L−1 NaCl (S) and Na2CO3 (A). The results showed that the inhibitory effect of the A treatment on rapeseed photosynthesis was greater than that of the S treatment, which was reflected in the higher Na+ content (73.30%) and lower photosynthetic-fluorescence parameters (6.30–61.54%) and antioxidant enzyme activity (53.13–77.10%) of the A-treated plants. The application of PPM increased the biomass (63.03–75.91%), photosynthetic parameters (10.55–34.06%), chlorophyll fluorescence parameters (33.83–62.52%), leaf pigment content (10.30–187.73%), and antioxidant enzyme activity (28.37–198.57%) under S and A treatments. However, the difference is that under the S treatment, PPM regulated the sulfur metabolism, carbon fixation and carbon metabolism pathways in rapeseed leaves. And it also regulated the photosynthesis-, oxidative phosphorylation-, and TCA cycle-related metabolic pathways in rapeseed leaves under A treatment. This study will provide new insights for the application of polymer materials to tackle the salinity stress on crops caused by drip irrigation with brackish water, and solve the difficulty in brackish water utilization. [ABSTRACT FROM AUTHOR]