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Salinity negatively impacts soil fertility by impairing the development and physiological functions of foxtail millet plants. Organic amendments have emerged as a viable solution in the reclamation and management of salinity inflicted soils and improve the performance of crop. In this regard, a pot experiment was carried out to examine the effect of organic amendments (OAs) on soil quality and its influence on the growth and physiology of foxtail millet under saline and non-saline condition. The findings indicated that under salt stress conditions, the levels of proline, hydrogen peroxide (H2O2), and electrolyte leakage (EL) risen, whilst other physiological parameters decrease in foxtail millet. However, the addition of OAs, particularly dhaincha and biochar (BC), has shown a promising salt tolerant amendment among others. Its addition improved the growth performance of salinity-stressed plants, including plant height, fresh and dry biomass, simultaneously decreased sodium ion (Na+) and improved calcium (Ca2+), potassium (K+), and nitrate ion (NO3−). They also increased proline build up by 6–17 %, reduced H2O2 (19–38 %) and malondialdehyde (16–18 %). Furthermore, they elevated the relative water content (RWC) (25 %), chlorophyll content, and reduced EL (29–50 %). Once more, dhaincha and BC enhanced the number of rhizobia, phosphorus-solubilizing bacteria (PSB) and overall bacterial population in the soil. In saline soil, daincha and BC could enhance soil organic matter (628 %), total nitrogen (1630 %), available phosphorus (32–38 %), and exchangeable potassium (54–73 %). A potential strategy for improving setaria italica performance under salt is suggested to be the following order, dhaincha > biochar > vermicompost > duckweed. The study would assist stakeholders in these salinity-prone areas in strategizing the use of OAs to their fallow land for cultivation and agricultural activities.

Vermicompost is an organic material that is abundant in humic acids and nutrients. It is obtained through the bio-oxidation and stabilization processes carried out by earthworms. It has been proven to bring several benefits to different soil properties, including bulk density, soil structure, and plant available water capacity (PAWC). This investigation was conducted to fill the knowledge gap in some critical factors related to vermicompost application, specifically the short-term influence of a single vermicompost application with increasing doses on soil wettability and physical quality of differently textured soils. Water repellency of vermicompost and soil/vermicompost mixtures was investigated at different moisture contents by the water drop penetration time test, whereas physical quality was assessed by 35 soil indicators related to bulk density, soil water retention curve, and pore size distribution function.Despite vermicompost showed from strong to severe hydrophobicity at moisture content lower than the field capacity, amended soils were at the most slightly water repellent thus indicating that, under field conditions, the hydrophobicity attributable to soil amendment with vermicompost could be considered negligible. Soil physical quality was effectively affected by vermicompost addiction with different outcomes depending on soil texture. Indicators linked to PAWC generally increased at increasing the vermicompost rate in the coarse soils whereas no significant effect was observed for intermediate and fine soils. For example, plant available water capacity of coarse-textured soils increased from an average initial value of 0.056 cm3 cm−3 to an optimal value of 0.15 cm3 cm−3 when a vermicompost addition dose of about one-third by volume (34 %) was applied. In the finest soil, drainable porosity significantly increased from an initial value of 0.09 cm3 cm−3 to 0.23 cm3 cm−3 when the maximum vermicompost dose (43 %) was applied thus indicating that amendment could be effective in enhancing water and air circulation.

Heavy-metal contamination in soil has long been a persistent challenge and the utilization of agricultural waste for in-situ stabilization remediation presents a promising approach to tackle this problem. Agricultural wastes exhibit promising potential in the remediation of contaminated land and modification could improve the adsorption performance markedly. Citric acid and Fe3O4 treated sugarcane bagasse adsorbed more heavy metals than raw materials in the aqueous system, employing these materials for heavy metal remediation in soil holds significant implications for broadening the raw material source of passivators and enhancing waste utilization efficiency. In this paper, a 120-day soil incubation study was conducted to compare the effects of pristine sugarcane bagasse (SB), citric-acid modified (SSB1, SSB2 and SSB3 with increasing proportion of citric acid) and citric-acid/Fe3O4 modified (MSB1, MSB4 and MSB7 with increasing proportion of Fe3O4) sugarcane bagasse at 1 % addition rate on cadmium (Cd) and copper (Cu) passivation. The SB, SSB1 and MSB1 did not always decrease the content of CaCl2-extractable Cd while all the seven amendments decreased the CaCl2-extractable Cu during the experiment period. Among all materials, SSB3 and MSB7 exhibited the highest efficiency in reducing the concentrations of CaCl2-extractable Cd and Cu. At Day 120, SB, SSB3 and MSB7 reduced the content of CaCl2-extractable Cd by 8 %, 18 % and 24 %, and of CaCl2-extractable Cu by 25 %, 50 % and 61 %, respectively. The efficiency of Cd and Cu immobilization was associated positively with the pH, functional groups and H-bonds of the amendments. The results suggest that the efficiency of sugarcane bagasse in heavy-metal passivation can be largely enhanced through chemical modifications using high proportions of citric acid and Fe3O4.

Increasing pressures on land resources requires increased land use efficiency. Over 900 million ha of sandy soils throughout the world are extensively used for agricultural crop production, most requiring nutrient inputs. Although use of humic substances together with inorganic fertilizer as soil amendments has been introduced, their synergistic effects on plant growth in sandy soils are not well addressed. We assessed the efficacy of a lignite waste derived humic substance on barley (Hordeum vulgare L.) growth, with and without inorganic fertilizer. Ten treatments were applied to sandy soils, comprising sole application of the humic product at four rates (NH1, NH2, NH3, NH4), sole application of fertilizer (F), and their combinations (F + NH1, F + NH2, F + NH3, F + NH4). Synergistic effects of nano humus and fertilizer were more notable than the corresponding sole application, particularly on plant biomass and seed production. Combined application with inorganic fertilizer increased root biomass by 92 % (0.1 g per plant), shoot biomass by 80 % (0.5 g per plant), root length by 24 % (3.6 cm), and seed production by 38 % (5 seeds per head) averagely relative to the untreated control, suggesting a strong synergistic effect. The increased seed production was particularly important from an agricultural perspective. Four application rates of nano humus all showed beneficial effects on barley growth with no significant differences. The most distinct positive effect of the humic product as a sole application was on root growth. Our study confirmed that a lignite waste derived humic product, nano humus, together with fertilizer may be an effective soil amendment to enhance agricultural plant growth in sandy soil regions.

The combination of soil amendments with plants can be a viable option for restoring the functionality of PTEs-contaminated soils. Soil recovery could be further optimized through the mixed cropping of plant species (e.g. legumes and grasses) with different physiological characteristics. The aim of this study was to assess the phytoremediation ability of Vicia villosa Roth. And Lolium rigidum Gaud. Grown alone or in mixture in a soil contaminated with PTEs (C), i.e. Cd (23 mg kg−1), Pb (4473 mg kg−1) and Zn (3147 mg kg−1), and amended with 3% biochar (C + B). Biochar improved soil fertility and changed PTEs distribution, reducing soluble fractions and increasing the more stable ones. The addition of biochar increased the plant biomass of hairy vetch and annual ryegrass, both in monoculture and when in mixture. For example, shoot and root biomass of the C + B intercropped hairy vetch and annual ryegrass increased 9- and 7-fold, and ∼3-fold respectively, compared to the respective C plants. The biochar addition decreased PTE-uptake by both plants, while mixed cropping increased the uptake of PTEs by shoots of hairy vetch grown in C and C + B. The bioaccumulation, translocation factors, and mineralomass showed that hairy vetch and annual ryegrass behaved as phytostabilising plants. PTE mineralomasses proved that mixed cropping in C + B increased the overall capacity of PTE accumulation by plant tissues, particularly the root system. Therefore, the combination of biochar and legumes/grasses mixed cropping could be an effective solution for the recovery of PTEs-contaminated soils and the mitigation of their environmental hazard.

Cadmium (Cd) pollution of soil and food crops is a widespread environmental issue caused by excessive industrialization, unsustainable urbanization, and intensive farming practices. Cd, a hazardous element, poses significant risks to agro-environmental sustainability, food safety, and human health. Using organic materials such as biochar and compost to stabilize Cd in contaminated soil is an environmentally benign and cost-effective strategy for remediating moderately to highly polluted soil. However, in response to the scarcity of comparative studies on biochar and compost efficacy, this research explores the impact of wheat-straw biochar and chicken waste compost on Cd-contaminated soil remediation. A greenhouse experiment using two application rates (1.5 % and 2.5 %) of biochar and compost in 10 mg kg−1 Cd-contaminated soil revealed significant (p≤0.05) effects. The 2.5 % compost application increased soil organic carbon (SOC) from 0.45 % to 0.85 %, while 2.5 % biochar enhanced soil pH from 7.1 to 7.7 and electrical conductivity (EC) from 0.33 to 0.44 dSm−1. Notably, 2.5 % biochar significantly reduced Cd bioavailability from 9.49 to 4.90 mg kg−1, root accumulation from 29.8 to 16.4 mg kg−1 and shoot translocation from 16.8 to 8.4 mg kg−1. This reduction was confirmed through translocation factor (51.5 %) and immobilization efficiency (48.4 %). Furthermore, 2.5 % biochar improved chlorophyll content (a, b, and total) and wheat morphological attributes under Cd stress in soil. Overall, higher rates of biochar (2.5 %) and compost (2.5 %) effectively mitigate Cd uptake, improve soil properties, and enhance physiological and morphological responses, suggesting their promise for sustainable soil management practices.

Organic fertilization and deep ploughing are expected to contribute to carbon (C) sequestration in arable soils. This hypothesis was evaluated over 11 years of chemical and organic fertilization under conventional tillage (20 cm) and deep ploughing (40 cm) in a rainfed sorghum-maize rotation system on the Loess Plateau. Soil was collected and analysed to determine the soil organic C (SOC) and total nitrogen (TN) contents in the soil profiles (0–60 cm) or in the macroaggregates, microaggregates and silt and clay fractions (0–20 cm only). The SOC and TN stocks at the 0–60 cm depth displayed a net decrease in the unfertilized control, a marginal increase with chemical fertilizer, a significant increase of 23–45 % and 19–42 %, respectively, with organic amendments and a significant increase of 54 % and 48 %, respectively, when combined with deep ploughing. A critical input amount of 2064 kg C ha−1 yr−1 or 162 kg N ha−1 yr−1 was found to be required to maintain the initial SOC or TN stock. The annual N input was positively correlated with the C sequestration efficiency (P

Soil organic carbon (SOC) is in the focus of research due to its central role in regulating climate and maintaining fertility and resilience of soils. Methodologically, shifting from whole soil C measurements to specific SOC fractions increases possibility to detect small changes in the vast SOC storage, and enhances estimation of SOC stability. However, SOC fractionation schemes are numerous and variable. In this study, deionized water and sodium hexametaphosphate (SHMP) were compared in soil dispersion by separating soils into coarse (0.25–2 mm), medium (0.063–0.25 mm) and fine (

Fractions of phosphorus (P) and its sorption characteristics are affected by different soil fertility (FM) technologies which ultimately affect crop growth and productivity. However, the response of P fractions and sorption characteristics to soil fertility technologies that integrate diverse amendments is still poorly understood in acidic Nitisols. A randomized complete block design was layout in an acidic Nitisol to determine fractions of P, its sorption characteristics and use efficiencies in acidic Nitisols under various FM technologies in field conditions. The use of minimum tillage + maize residue + inorganic fertilizer + goat manure (MTCrGF) had the highest impact on and significantly increased resin-Pi, NaHCO3-Pi, and maximum P sorption (Smax) by 182, 76, and 52 mg P kg−1. Moreover, NaOH-Pi and Smax concentrations were higher under conventional tillage + maize residue + inorganic fertilizer + goat manure (CTCrGF) by 216 mg P kg−1 and 49 mg P kg−1 than the control. MTCrGF and CTCrGF also had the lowest P bonding energy (0.04 L mg−1). CTCrGF had the highest P partial productivity factor (0.093 and 0.140 kg biomass kg−1 P) and P agronomic efficiency (0.080 and 0.073 kg biomass kg−1 P) during the two cropping seasons. The results demonstrate the positive influence of combining multiple P sources on soil P fractions, sorption characteristics, and use efficiencies. Notably, combining either conventional or minimum tillage with maize straw and applying integrated manure and inorganic fertilizer (MTCrGF or CTCrGF) can increase the labile P concentrations and reduce the potential depletion of the non-renewable rock phosphate and the use of inorganic phosphatic fertilizers for agricultural production.

This study assessed the viability of the combined use of coal processing waste (CPW), rice processing waste (RPW), poultry agro-industry sludge (PAS), synthetic gypsum (SG), topsoil (TS), and B horizon soil (BH) to reclaim areas degraded by coal mining. A Classification, Potentiality, Quantity/viability, and Application (CPQvA) systematic was employed to assess the feasibility of using these waste and materials to construct technosols. An experiment consisting of five technosols (T-1–T-5) was replicated four times in a completely randomized block design. Technosols fertility was analyzed 12 months after the establishment of the experiment. The mean fertility parameters, presented as mean ± 1 SD, were subjected to one-way analysis of variance, and the differences were tested using Tukey's test (P

Soil organic carbon (SOC) and nitrogen (N) are two of the most important indicators for agricultural productivity. The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile (up to 100 cm) and their relationships with crop productivity under the influence of long-term (since 1990) fertilization in the wheat-maize cropping system. Treatments included CK (control), NP (inorganic N and phosphorus (P) fertilizers), NPK (inorganic N, P and potassium fertilizers), NPKM (NPK plus manure), and M (manure). Crop yield and the properties of topsoil were measured yearly from 2001 to 2009. C and N contents were measured at five different depths in 2001 and 2009. The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer (NP and NPK) treatments. The average yield between 2001 and 2009 under the NP, NPK, NPKM, and M treatments (compared with the CK treatment) increased by 38, 115, 383, and 381%, respectively, for wheat and 348, 891, 2 738, and 1 845%, respectively, for maize. Different long-term fertilization treatments significantly changed coarse free particulate (cfPOC), fine free particulate (ffPOC), intramicroaggregate particulate (iPOC), and mineral-associated (mSOC) organic carbon fractions. In the experimental years of 2001 and 2009, soil fractions occurred in the following order for all treatments: mSOC>cfPOC>iPOC>ffPOC. All fractions were higher under the manure application treatments than under the inorganic fertilization treatments. Compared to the inorganic fertilization treatments, manure input enhanced the stocks of SOC and total N in the surface layer (0–20 cm) but decreased SOC and N in the deep soil layer (80–100 cm). This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients, especially N, compared to inorganic fertilization treatments. The findings provide opportunities for understanding deep soil C and N dynamics, which could help mitigate climate change impact on agricultural production and maintain soil health.

The excessive application of phosphorus (P) fertiliser and its poor utilisation efficiency have led to significant amounts of P being retained in agricultural soils in unavailable forms. The application of alkaline lignin to soil and its inoculation with arbuscular mycorrhizal fungi (AMF) have both been shown to improve plant P nutrition. However, their combined effects on soil P transformation remain unclear, particularly in cadmium (Cd)-contaminated soils. A potting experiment was conducted to examine the combined effects of AMF and alkaline lignin on soil P and Cd bioavailability and on the uptake of P and Cd by lettuce (Lactuca sativa L.) that were grown for 56 d in a growth chamber. Combined AMF and alkaline lignin treatment increased soil P availability and alkaline phosphatase activity. It furthermore increased bioavailable Cd concentrations of rhizosphere and bulk soils by 48 % and 72 %, respectively, and the Cd concentration in roots by 85 %, but the Cd concentration was not affected in the edible parts (shoots) of the lettuce. Moreover, the combined treatment increased shoot biomass by 26-70 % and root biomass by 99-164 %. Our findings suggested that the combined use of AMF and alkaline lignin mobilised both P and Cd in soil but did not increase the accumulation of Cd in the shoots of plants growing in Cd-contaminated soils, these results would provide guideline for increasing Cd tolerance of plants and their yield., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biochar is a charcoal-like substance produced by pyrolisis of organic material from agricultural and forestry wastes, that can improve soil and substrates physical and chemical properties in the field and in plant nurseries. Despite some studies showing the advantages of its use in forestry nurseries, other studies show that biochar effects on seedling growth and quality are variable, and depends on the specific properties of the biochar and the particular species response to it. The objective of this study was to evaluate, through the analysis of the substrate and plant measurements, the effect of biochar produced from Acacia mangium Willd wood residues on the production of the same species seedlings. An experiment with complete factorial design, in a completely randomized arrangement, was established, with 9 treatments resulting from the combination of A. mangium biochar (BAM) and synthetic fertilizer (FS), with 3 dose levels for BAM: 0, 40, and 80 ton · ha−1 and 3 levels for the FS: 0% 50% and 100% of common fertilizer practice in the studied region of Colombia. The quality of the seedlings was estimated using the Dickson index (DQI), which considers the size and biomass allocation of the plant. The addition of BAM + FS increased the cationic exchange capacity, nitrogen, phosphorus, organic matter and carbon in the substrate without modifying the pH or the concentrations of calcium and potassium. Foliar analysis showed an increase in these cations in BAM treatments. An increase of over 130% was found in the DQI of seedlings with BAM + FS, but an intermediate dose of both elements was required to achieve this improvement in seedling quality. Neither of the two fertilizer alternatives alone resulted in good seedling quality.

Cadmium (Cd) is a heavy metal that neutrally occurs in soil. It is carcinogenic in humans and caused a significant decline in the plant’s growth when up has taken beyond the threshold limit. The fertilizers, manure, sewage sludge, and aerial deposition are the main source of cadmium contamination in soil. Furthermore, poor soil organic matter is also one of the allied factors which facilitate the development of Cd toxicity in soil. The decomposition resistance nature of biochar makes it an effective amendment for cadmium remediation. Through crop production, Cd enters the food system. Individual studies on biochar and compost are found in the literature but the combined effect of biochar and compost are rarely documented especially in maize crops. The current pot study was conducted in Pesticide Quality Control Laboratory, Multan, Pakistan. However, the current study was novel and conducted by using compost mixed biochar (CB) against Cd toxicity in maize. Four application rates of CB i.e., 0, 0.50, 0.75 and 1.00% (1.00CB) were applied under 3 levels of Cd i.e., 0 (0Cd), 2.5 (2.5Cd) and 5 mg Cd kg−1 soil (5.0Cd). Overall, results indicated that 1.00%CB remained significantly best at higher 5.0Cd for improvement in soil organic matter, plant height, root length, number of leaves, leaves fresh and dry weight, plant fresh and dry weight, chlorophyll a, b, total and carotenoids. A significant decrease in soil pHs, leaves anthocyanin and lycopene also validated the efficacious functioning of 1.00%CB over control in 2.5 and 5.0Cd. In conclusion, the use of 1.00%CB is a better approach to decrease Cd harmful effects to improve gas exchange attributes, growth and chlorophyll contents in maize. Long-term research is required on co-composted biochar toward mitigation of cadmium toxicity under different geographical locations.

Production of brinjal (Solanum melongena L.) is considerably reduced by infestations of root-knot nematodes (RKN). As chemical pesticides are increasingly being regulated globally, scientists are focusing on biorational management. An experiment was undertaken to screen resistant brinjal cultivars in Bangladesh against Meloidogyne javanica in a pot trial. Pot and field trials were also conducted to evaluate the efficacy and profitability of individual and combined applications of several biorational components to manage M. javanica on brinjal. Of twenty brinjal cultivars screened, cv. Noagram was found ‘moderately resistant’ and others were ‘susceptible’ to ‘highly susceptible’ against M. javanica. In both pot and field trials, most of the growth parameters of brinjal and reproductive parameters of M. javanica were significantly different than the control for both the individual and combined treatments of different biorational components which included cabbage, marigold, vermicompost, biogas digestate, Bacillus subtilis and Pseudomonas fluorescens. The yield was significantly higher for the combined treatments than the individual applications. The benefit-cost ratio (BCR) differed among the treatments. The highest yield (29.5 t/ha) and BCR (3.67) with the lowest reproductive factor (0.33) was obtained by the combined application of biogas digestate and B. subtilis. This is the first report on the efficiency and profitability assessment of biogas digestate in combination with a bio-agent in addressing the management of RKN, which might be very important considering the global concern of environmental pollution. The cultivar Noagram might be a potential source of resistant genes in brinjal against M. javanica.

Ghana is the second largest producer of cocoa in the world and cocoa farming supports the livelihoods of 25-30% of Ghana's population. However, average yield is only about 30% of the potential yield. Cocoa farms established on recently cleared rainforest are initially productive, but then productivity declines as soils become depleted of nutrients. Further expansion of cultivated land by deforesting tropical rainforests is environmentally costly, socially unacceptable, and inherently unsustainable. Therefore, strategies are urgently required to maintain and restore the productivity of existing smallholder farms to close this yield gap and sustainably increase cocoa production to meet growing demand. In this narrative review we provide context to the issues and highlight recent advances that offer promising opportunities to restore the soil health of Ghana's cocoa farms and sustainably reduce the yield gap. The shade trees in traditional agroforestry farms help prolong productivity for longer by supporting soil ecological functions and this has sparked renewed interest in the establishment of sustainable agroforestry cocoa farms. The single rate and formulation of mineral fertiliser recommended to farmers nationwide fails to account for variability in the response of different soil types to inputs. Therefore, site-specific fertiliser recommendations that also quantify the benefits of organic amendments are emerging. Composting and returning cocoa pod husks to the soil offers a considerable opportunity to close nutrient cycles (particularly for P and K) on cocoa farms and to help build and maintain soil organic matter. However, research is required to overcome the risk that recycling cocoa pod husks may contribute to the spread of black pod disease. Soil health indicators that quantify the soil ecological functions provided by these sustainable land management practices require benchmarking to monitor the impact of these interventions.

Sludge generation from wastewater treatment plants in Uruguay has increased in recent years. Agricultural soils may be a final destination. A greenhouse experiment was conducted to quantify the effect of this sludge on 1) plant biomass production and nutrient concentration of sorghum (Sorghum bicolor var. vulgare); 2) the chemical properties of amended soils; and 3) assess whether heavy metal concentrations in sludge are appropriate according to environmental regulations. Two soils (S1 and S2) were amended with pure sludge (PS) and limed sludge (LS), with low dose (LD) of 16.0 and 17.3 Mg ha−1 and high dose (HD) of 32.0 and 34.6 Mg ha−1, respectively. Sludge treatments increased plants' nutrient absorption and dry matter production. The LS treatments incremented plant biomass production, depending on soil pH and nutrient availability. The effect of sludge treatments on elemental concentration in aboveground biomass depended on the element, treatments, and soil type. Mineralized nitrogen (N) and plant available phosphorus (P-Bray 1) values increased with sludge addition without exceeding Uruguay's critical soil level of P-Bray 1 for the sorghum crop. The PS did not increase metal concentration in soils. The LS slightly decreased soil Pb and slightly increased Cr and Zn soil concentration; levels were according to Uruguayan environmental guidelines. Therefore, agriculture soils are a viable final destination for PS and LS. Land applied sludge has acceptable levels of metals and promotes crop development.

Heavy-metal contamination in soil has long been a persistent challenge and the utilization of agricultural waste for in-situ stabilization remediation presents a promising approach to tackle this problem. Agricultural wastes exhibit promising potential in the remediation of contaminated land and modification could improve the adsorption performance markedly. Citric acid and Fe 3 O 4 treated sugarcane bagasse adsorbed more heavy metals than raw materials in the aqueous system, employing these materials for heavy metal remediation in soil holds significant implications for broadening the raw material source of passivators and enhancing waste utilization efficiency. In this paper, a 120-day soil incubation study was conducted to compare the effects of pristine sugarcane bagasse (SB), citric-acid modified (SSB1, SSB2 and SSB3 with increasing proportion of citric acid) and citric-acid/Fe 3 O 4 modified (MSB1, MSB4 and MSB7 with increasing proportion of Fe 3 O 4 ) sugarcane bagasse at 1 % addition rate on cadmium (Cd) and copper (Cu) passivation. The SB, SSB1 and MSB1 did not always decrease the content of CaCl 2 -extractable Cd while all the seven amendments decreased the CaCl 2 -extractable Cu during the experiment period. Among all materials, SSB3 and MSB7 exhibited the highest efficiency in reducing the concentrations of CaCl 2 -extractable Cd and Cu. At Day 120, SB, SSB3 and MSB7 reduced the content of CaCl 2 -extractable Cd by 8 %, 18 % and 24 %, and of CaCl 2 -extractable Cu by 25 %, 50 % and 61 %, respectively. The efficiency of Cd and Cu immobilization was associated positively with the pH, functional groups and H-bonds of the amendments. The results suggest that the efficiency of sugarcane bagasse in heavy-metal passivation can be largely enhanced through chemical modifications using high proportions of citric acid and Fe 3 O 4 ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Wastewater irrigation in croplands is recognized as one of the major threat, seriously affecting soil health and sustainable agriculture around the globe. Heavy metals presence especially cadmium (Cd) in wastewater irrigated soils is posing serious physiological and morphological disorder in plants due to its highest mobility. Therefore, metals mobility in wastewater irrigated soils can be curtailed through eco-friendly and cost effective organic soil amendments compost (CP), press mud (PM) and moringa leaf extract (ME) at 3% rate that eventually reduces its translocation from polluted soil to plant. This study explored the possible effects of various types of organic soil amendments on Cd phytoavailability in wastewater degraded soil and its subsequent accumulation in maize tissues. Maize plant was grown in Ghazi University as a test plant and Cd accumulation was recorded in its tissues, translocation from root to shoot, chlorophyll contents, plant biomass, yield and soil properties (pH, NPK, OM and Soluble Cd) were also examined. Results revealed that the addition of amendments significantly minimized Cd mobility in soil by 45.8%, 23% and 19.4% when CP, PM and ME were added at 3% over control. Comparing the control soil, Cd uptake effectively reduced via plants shoots by 33.3%, 27.7% and 19.4% when CP, PM and ME. In addition, NPK were significantly increased among all the added treatments in the soil-plant system as well as improved chlorophyll contents relative to non-treated soil. The Current study suggested that among all the amendments, compost at 3% rate performed well and can be considered a suitable approach for maize growth in polluted soil.

Locally available organic inputs to soil, solely or in combination with inorganic fertilizers, are used to reverse declining soil fertility and improve soil organic matter content (SOM) in smallholder farms of most Sub-Saharan Africa (SSA) countries. Soil organic matter characterization can indicate soil organic input, carbon (C) sequestration potential, or even an authentication tool for soil C dynamics in C stocks accounting. This study determined the effects of the long-term application of selected integrated soil fertility management (ISFM) technologies on SOM functional group composition and maize yields. The study was carried out on an ongoing long-term soil fertility field experiment established in 2004 in Mbeere South sub-county, the drier part of upper Eastern Kenya. The experimental design was a randomized complete block design. The ISFM treatments were 60 kg ha−1 nitrogen (N) from goat manure (GM60); 30 kg ha−1 inorganic N fertilizer (IF30); 60 kg ha−1 inorganic N fertilizer (IF60); GM30+IF30; 90 kg ha−1 inorganic N fertilizer (IF90); 60 kg ha−1 N from lantana (Lantana camara) (LC60); LC30+IF30; 60 kg ha−1 N from mucuna beans (Mucuna pruriens) (MP60); MP30+IF30; 60 kg ha−1 N from Mexican sunflower (Tithonia diversifolia) (TD60); TD30+IF30, and a control with no inputs. The C compositions of ground soil samples and organic amendments were analyzed using 13C solid-state NMR. The GM60, GM30+IF30, LC60, and TD60 treatments had much higher Alkyl and O-Alkyl C SOM functional groups than the control and other treatments. The average soil C for the control was 7.47 mg kg−1 and ranged from 5.03 to 7.37, 9.57 to 18.77, and 7.03–14.50 mg kg−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The mean grain yield for the control was 0.56 Mg ha−1 and ranged from 1.51 to 1.99, 1.94 to 4.16, and 2.98–4.60 Mg ha−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The results showed that a long-term application of sole organic fertilizers or combined with inorganic fertilizers increases maize yield and soil C sequestration potential. The increase was attributed to high Alkyl and O-Alkyl C SOM functional groups. Hence, knowing the C fraction content of organic inputs is vital in determining the best-fit management technologies for ameliorating soil fertility and sustaining and/or improving crop yields.

Bioenergy feedstock production on degraded land can serve as a means for modulating land competition for food versus energy. Due to little or no agricultural value of degraded soil, fortification of the soil with an organic amendment or inoculum will improve biomass productivity. However, as farmers struggle to rejuvenate their degraded land, there is a need for a quick screening strategy to select the best method of enhancing cellulosic (switchgrass, SG) biomass production in degraded soil. The goal of this study is to evaluate the effects of soil amendment and inoculation strategies on biomass productivities of SG in a reclaimed surface-mined soil (RMS). Experiments were conducted in the greenhouse using moisture replacement microcosms (MRM) to screen strategies for enhancing biomass productivities of SG in a RMS. Strategies included soil amendment with organic by-products (poultry litter, paper mill sludge, and vermicompost), inorganic nutrients (nitrogen and phosphorus fertilizers), or a commercial preparation of endomycorrhizae fungi (AMF, BioVam). Experiments were implemented with ten (10) treatments with six replicates for each treatment. After eight weeks of incubation in MRM systems, inoculation of RMS with AMF produced the highest aboveground and total biomass (0.9 g and 1.77 g per microcosm container) at p AMF + VC > PMS + N > VC = PMS = PL > PMS + AMF > N + P > ASL > Control. This microcosm screening experiment served as a quick screening to establish that soil enhancement and inoculation strategies can enhance biomass productivities of SG in degraded soil.

Different techniques have been developed for the remediation of Cu contaminated soils, being the phytoremediation a sustainable and environmentally friendly strategy, but its use in mine tailings is scarce. Arbuscular mycorrhizal fungi (AMF) can decrease the Cu concentration in plants by favouring the stabilization of this metal through different mechanisms such as the production of glomalin, immobilization in the fungal wall of hyphae and spores, and the storage of Cu in vacuoles. Additionally, the use of organic amendments promotes the beneficial effects produced by AMF and improves plant growth. Based on the above, the aim of this study was to determine the effect of AMF inoculation and compost application at different doses on the growth of Oenothera picensis in a Cu mine tailing. One group of plants were inoculated with Claroideoglomus claroideum (CC) and other was non-inoculated (NM). Both CC and NM were grown for two month under greenhouse conditions in pots with the Cu mine tailing, which also had increasing compost doses (0%, 2.5%, 5%, and 10%). Results showed greater biomass production of O. picensis by CC up to 2-fold compared with NM. This effect was improved by the compost addition, especially at doses of 5% and 10%. Therefore, the increase of mycorrhizal and nutritional parameters in O. picensis, and the decreasing of Cu availability in the mine tailing, promoted the production of photosynthetic pigments together with the plant growth, which is of importance to accomplish phytoremediation programs in Cu mine tailings.

Quantification of nitrogen (N) cycling genes contributes to our best understanding of N transformation processes. The application of organic amendment (OA) is widely recognized as an effective measure to improve N management and soil fertility in various ecosystems. However, our understanding of N-cycling gene abundances in response to OA application remains deficient. We performed a meta-analysis embracing 124 sets of observation data to study the impact of OA application on the main N-cycling gene abundances, including nifH, amoA, nirS, nirK and nosZ. We found that the significantly positive response of N-cycling gene abundances to OA application was attributed to the rotation cropping system (by 6.45 %-104.20 %) in the field experiment (by 19.43 %-52.56 %), OA application alone (by 8.29 %-111.70 %) especially manure addition (by 33.43 %-98.70 %), application dose of OAs within 10-20 t ha -1 (by 45.33 %-381.90 %), fertilization duration <5 years (by 43.69 %-112.63 %), C/N of OA <25 (by 37.87 %-160.90 %), SOC lower than 1.2 % (by 41.44 %-157.89 %) and application to alkaline soil (by 32.24 %-134.40 %). Moreover, soil organic carbon (SOC) and pH were the most essential regulators associated with N-cycling gene abundances with OA application. Identification of key driving factors of the abundance of N-cycling functional genes will help remedy strategies for managing OAs in ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Anthropogenic disturbance of soils can disrupt soil structure, diminish fertility, alter soil chemical properties, and cause erosion. Current remediation practices involve amending degraded urban topsoils lacking in organic matter and nutrition with organic amendments (OA) to enhance vegetative growth. However, the impact of OAs on water quality and structural properties at rates that meet common topsoil organic matter specifications need to be studied and understood. This study tested three commonly available OAs: shredded wood mulch, leaf-based compost, and class A Exceptional Quality stabilized sewage sludge (or biosolids) for nutrient (nitrogen and phosphorus) water quality, soil shear strength, and hydraulic properties, through two greenhouse tub studies. Findings showed that nitrogen losses to leachate were greater in the biosolids amended topsoils compared to leaf-compost, mulch amended topsoils, and control treatments. Steady-state mean total nitrogen (N) concentrations from biosolids treatment exceeded typical highway stormwater concentrations by at least 25 times. Soil total N content combined with the carbon:nitrogen ratio were identified to be the governing properties of N leaching in soils. Study soils, irrespective of the type of amendment, reduced the applied (tap) water phosphorus (P) concentration of ∼0.3 mg-P/L throughout the experiment. Contrary to the effects on N leaching, P was successfully retained by the biosolids amendment, due to the presence of greater active iron contents. A breakthrough mechanism for P was observed in leaf compost amended soil, where the effluent concentrations of P continued to increase with each rainfall application, possibly due to an saturation of soil adsorption sites. The addition of OAs also improved the strength and hydraulic properties of soils. The effective interlocking mechanisms between the soil and OA surfaces could provide soil its required strength and stability, particularly on slopes. OAs also improved soil fertility to promote turf growth. Presence of vegetative root zones can further reinforce the soil and control erosion., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Sai Thejaswini Pamuru, Jennifer Morash, John D. Lea-Cox, Andrew G. Ristvey, Allen P. Davis, and Ahmet H. Aydilek report financial support was provided by Maryland Department of Transportation – State Highway Administration. Sai Thejaswini Pamuru & Jennifer Morash report financial support was provided by NSF Research Traineeship (UMD Global STEWARDS) Grant 1828910., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Abstract: Excessive use of agro-chemicals (such as mineral fertilizers) poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmentally sound approaches to develop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009–2012. The experiment included four treatments: 100% chemical fertilizer (CF100), 80% chemical fertilizer (CF80), 60% chemical fertilizer and 20% organic fertilizer (CF60+OM20), and 40% chemical fertilizer and 40% organic fertilizer (CF40+OM40). Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction (CF80) had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer (CF60+OM20, CF40+OM40) significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continuous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.

The fate and behavior of herbicides can be altered in an unpredictable way when organic amendments are added to soil as a beneficial management tool. The objective of this work was to investigate the effect exerted by the addition of two different organic amendments (alperujo compost and biochar) to soil in the degradation of one of the most relevant new generation rice herbicides, profoxydim. In unamended soils, the degradation of profoxydim was quite fast and was governed by both chemical (DT50 steril soil  = from 1.52 to 9.21 days) and microbial (DT50 nonsterile soil  = from 0.47 to 0.53 days) processes. Alperujo- and biochar-amended soils significantly increased the persistence of the herbicide in both soils, especially in the presence of biochar, due to the high capacity absorption of this amendment, increasing DT90 from 1.92 to 3.54 days for DT90 unamended to 41.02-48.41 days for DT90 biochar amended . Different kinetics models applied to fit the observed dissipation datasets showed that a HS biphasic model fits well with the dissipation of profoxydim in amended and unamended soils. For the first time, five degradation products (DPs) were identified by HPLC-QTOF-MS/MS in soil and a degradation pathway was described. Main DP was generated via oxidation of the sulfur atom to give rise to the corresponding sulfoxide derivative, with this DP being more persistent than the active substance. These outcomes can be very useful for the assessment of the environmental risk associated with the use of profoxydim in rice crops and the application of organic amendments as potential measures for minimizing the risk of contamination of natural water resources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Global changes, particularly rising temperatures, threaten food security in smallholder mountain communities by impacting the suitability of cultivation areas for many crops. Land-use intensification, associated with agrochemical use and tillage, threatens soil health and overall agroecosystem resilience. In the Andean region, farmers often cultivate crops at multiple elevations. Warming climates have led to a shift in cultivation upslope, but this is not feasible in many areas. Traditional soil fertility management practices together with a focus on traditional (orphan) crops offers promise to cope with rapid climate warming in the region. To understand the impacts of warming and changing nutrient management, we established two side-by-side experiments using the traditional Andean crops Oxalis tuberosa (Oca) and Lupinus mutabilis (Tarwi) at three elevations, each with two fertility treatments (organic and synthetic). Soil and climate data (i.e., temperature and precipitation) were collected throughout the growing season, and crop performance was evaluated through impacts on yield and other growth metrics (e.g., biomass, pest incidence). We used two-way ANOVA to assess the influence of site (elevation) and management type (organic vs. synthetic) on crop performance. Results indicated that warmer climates (i.e., lowest elevation) negatively impact the production and performance of O. tuberosa, but that organic fertilization (sheep manure) can help maintain crop yield and biomass production in warmer conditions relatively to synthetic nutrient inputs. In contrast, L. mutabilis showed accelerated growth in warmer conditions, but grain yield and biomass production were not significantly affected by site and showed no interaction with nutrient management. Our findings highlight that climate warming represents a serious threat to small-scale crop production in the Peruvian Andes and could cause severe declines in the production of locally important crops. Additionally, the continued reliance on traditional crops with organic inputs, instead of synthetic fertilizers, may help support agricultural productivity and resilience under climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Biochar has been shown to reduce soil greenhouse gas (GHG) and increase nutrient retention in soil; however, the interaction between biochar and organic amendments on GHG emissions remain largely unclear. In this study, we collected 162 two-factor observations to explore how biochar and organic amendments jointly affect soil GHG emissions. Our results showed that biochar addition significantly increased soil CO 2 emission by 8.62 %, but reduced CH 4 and N 2 O emissions by 27.0 % and 23.9 %, respectively. Meanwhile, organic amendments and the co-application with biochar resulted in an increase of global warming potential based on the 100-year time horizon (GWP 100 ) by an average of 18.3 % and 26.1 %. More importantly, the interactive effect of biochar and organic amendments on CO 2 emission was antagonistic (the combined effect was weaker than the sum of their individual effects), while additive on CH 4 and N 2 O emissions. Additionally, our results suggested that when biochar is co-applied with organic amendments, soil GHG emissions were largely influenced by soil initial total carbon, soil texture, and biochar feedstocks. Our work highlights the important interactive effects of biochar and organic amendments on soil GHG emissions, and provides new insights for promoting ecosystem sustainability as well as mitigating future climate change., Competing Interests: Declaration of competing interest The authors declared no conflict of interests., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Soil organic carbon (SOC) is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expansion in south China. A study was carried out to evaluate the relationship between the SOC content and organic carbon input under various organic amendments at a long-term fertilization experiment that was established on a red soil under a double rice cropping system in 1981. The treatments included non-fertilization (CK), nitrogen-phosphorus-potassium fertilization in early rice only (NPK), green manure (Astragalus sinicus L.) in early rice only (OM1), high rate of green manure in early rice only (OM2), combined green manure in early rice and farmyard manure in late rice (OM3), combined green manure in early rice, farmyard manure in late rice and rice straw mulching in winter (OM4), combined green manure in early rice and rice straw mulching in winter (OM5). Our data showed that the SOC content was the highest under OM3 and OM4, followed by OM1, OM2 and OM5, then NPK fertilization, and the lowest under non-fertilization. However, our analyses in SOC stock indicated a significant difference between OM3 (33.9 t ha−1) and OM4 (31.8 t ha−1), but no difference between NPK fertilization (27 t ha−1) and non-fertilization (28.1 t ha−1). There was a significant linear increase in SOC over time for all treatments, and the slop of linear equation was greater in organic manure treatments (0.276–0.344 g kg−1 yr−1) than in chemical fertilizer (0.216 g kg−1 yr−1) and no fertilizer (0.127 g kg−1 yr−1).

Organic amendments are important sources of nitrous oxide (N 2 O) emissions from agricultural soils. In 2020, the total amount of N in organic amendments applied to Japanese agricultural soils (440 ktN) was larger than that of synthetic fertilizer (374 ktN). However, N 2 O emissions from organic amendments were estimated by using the country-specific N 2 O emission factor (EF) for synthetic fertilizer (0.31 % for rice paddy, 2.9 % for tea, and 0.62 % for other crops) in the National Greenhouse Gas Inventory Report of Japan. Thus, we conducted a N 2 O flux measurement campaign at 12 different experimental sites across Japan to estimate fertilizer-induced N 2 O EFs for major organic amendments in Japan, that is, poultry manure compost, swine manure compost, cattle manure compost, and organic fertilizer pellets. In addition, we conducted systematic review of N 2 O emissions and EFs for organic amendments, including data from our measurement campaign and published data from peer-reviewed papers in Japan. The final dataset, including the field measurement campaign and published data, resulted in 404 observations (including synthetic fertilizer and zero-N control) in 29 sites. Results showed that soil type affected EFs, that is, the mean EF of Andosols was lower than that of non-Andosols, which is similar to the case of EFs for synthetic fertilizer. Mean EFs for poultry manure compost, swine manure compost, cattle manure (compost and slurry), and non-animal manure organic fertilizers were 0.83 % (uncertainty range of 2.5th and 97.5th percentile: 0.09 % to 3.46 %), 0.70 % (0.02 % to 2.45 %), 0.39 % (0.00 % to 1.62 %), and 1.16 % (0.41 % to 3.03 %), respectively, when weighted by area of soil types. The mean EF of all organic amendments was 0.84 % (0.00 % to 2.91 %), when the area of soil type and amount of organic amendment used in Japan were considered. Our study provides country-specific EFs to estimate N 2 O emission from organic amendments in Japan., Competing Interests: Declaration of competing interest Hiroko Akiyama reports financial support was provided by Ministry of Agriculture Forestry and Fisheries., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Vast amounts of plastic waste are causing serious environmental issues and urge to develop of new remediation methods. The aim of the study is to determine the role of inorganic (nitric acid), organic (starch addition), and biological (Pseudomonas aeruginosa) soil amendments on the degradation of Polyethylene (PE) and phytotoxic assessment for the growth of lettuce plant. The PE-degrading bacteria were isolated from the plastic-contaminated soil. The strain was identified as Pseudomonas aeruginosa (OP007126) and showed the highest degradation percentage for PE. PE was pre-treated with nitric acid as well as starch and incubated in the soil, whereas P. aeruginosa was also inoculated in PE-contaminated soils. Different combinations were also tested. FTIR analysis and weight reduction showed that though nitric acid was efficient in degradation, the combined application of starch and bacteria also showed effective degradation of PE. Phytotoxicity was assessed using morphological, physiological, and biochemical parameters of plant. Untreated PE significantly affected plants' physiology, resulting in a 45% reduction in leaf chlorophyll and a 40% reduction in relative water content. It also had adverse effects on the biochemical parameters of lettuce. Bacterial inoculation and starch treatment mitigated the harmful impact of stress and improved plants' growth as well as physiological and biochemical parameters; however, the nitric treatment proved phytotoxic. The observed results revealed that bacteria and starch could be effectively used for the degradation of pre-treated PE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Inc.)

In orchard systems, organic amendments and cover crops may enhance soil organic carbon (SOC) and total nitrogen (STN) stocks, but on a global scale a comprehensive understanding of these practices is needed. This study reports a worldwide meta-analysis of 131 peer-reviewed publications, to quantify potential SOC and STN accumulation in orchard soils induced by organic fertilization and cover cropping. Annual gains of 3.73 Mg C/ha and 0.38 Mg N/ha were realized with the introduction of organic fertilizer, while cover crop management led to annual increases of 2.00 Mg C/ha and 0.20 Mg N/ha. The SOC and STN accumulation rates depended mostly on climatic conditions and initial SOC and STN content. The SOC and STN accumulated fastest during the first three years of cover crop implementation, at 2.98 Mg C/ha/yr and 0.25 Mg N/ha/yr and declined thereafter. Organic fertilization caused significantly more annual SOC and STN accumulation at higher (400-800 mm) than lower (<400 mm) rainfall levels. When cover cropping for more than five years, SOC accumulated the fastest with <800 mm of mean annual rainfall. Organic fertilization led to faster SOC accumulation with mean annual temperature between 15 and 20 °C than >20 °C. Organic amendments led to the slowest SOC accumulation rate when the initial SOC concentration was <10 g C/kg. This study provides policy makers and orchard managers science-based evidence to help guide adaptive management practices that build SOC stocks, improve soil conditions and enhance resilience of orchard systems to climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The global consumption of plastic is growing year by year, producing small plastic pieces known as microplastics (MPs) that adversely affect ecosystems. The use of organic amendments (compost and manure) polluted with MPs affects the quality of agricultural soils, and these MPs can be incorporated into the food chain and negatively impact human health. Current European legislation only considers large plastic particles in organic amendments. There is no information regarding MP pollution. Thus, the development of a methodology to support future legislation ensuring the quality of agricultural soils and food safety is necessary. This proposed methodology is based on thermogravimetry coupled with mass spectrometry to quantify polyethylene and polystyrene (PE and PS) MPs through their mass spectrometry signal intensity of characteristic PE (m/z 41, 43 and 56) and PS (m/z 78 and 104) ions. This method has been validated with several organic amendments where the MP content ranged from 52.6 to 4365.7 mg kg -1 for PE-MPs and from 1.1 to 64.3 mg kg -1 for PS-MPs. The proposed methodology is a quick and robust analytical method to quantify MPs in organic amendments that could support new legislation., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Tea plantation can cause strong soil degradation, e.g. acidification, basic nutrient decrease and microbial diversity loss, naturally by its root activity and secondary by practically tremendous synthetic N input. Organic amendments application is considered a practical way to mitigate the above adverse consequence. However, the trade-off between agronomic and environmental effects on the application of the organic amendments is still under debate. Herein, we conducted a long-term field experiment with four treatments, including control (without and fertiliser) (CK), chemical fertiliser treatment (CF), chicken manure treatment (CM) and chicken manure combined with biochar treatment (CMB) to investigate the effects of organic amendments application on soil quality, heavy metal contamination and tea production in a tea plantation. Totally 16 plots were arranged randomly with a completely randomised design. The results showed that CM and CMB treatments improved soil nutrient, mitigated soil acidification and ameliorated soil porosity compared to CF treatment. CMB treatment displayed a relatively high tea yield and quality in three consecutive years of monitoring. However, CM and CMB treatments elevated the heavy metal (HM) potential ecological risk (RI) and Nemerow's composite index (Ps). CM treatment significantly increased available As, Pb, Cu and Zn concentrations compared to CF treatment, while CMB treatment significantly decreased available Cr and Cu concentrations and slightly decreased available Cd, Pb and Ni concentrations compared to CM treatment. But the increase of available As and Zn in CMB treatment compared to CM treatment also indicated adverse effects of biochar addition. The PLS-PM model showed HM risk had direct negative effects on tea quality. Moreover, soil fungal community revealed positive effects on tea yield and negative effects on tea quality. Overall, our study proved that CMB treatment could improve soil quality, reduce available Cr and Ni concentrations, maintain tea yield and increase tea quality., Competing Interests: Declaration of Competing Interest The authors have declared no conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The extreme characteristics of mine tailings generally prohibit microbial processes and natural plant growth. Consequently, vast and numerous tailings sites remain barren for decades and highly susceptible to windblown dust and water erosion. Amendment-assisted phytostabilization is a cost-effective and ecologically productive approach to mitigate the potential transport of residual metals. Due to the contrasting and complementary characteristics of biosolids (BS) and biochar (BC), co-application might be more efficient than individually applied. Studies considering BS and BC co-application for multi-metal tailings revegetation are scarce. As tailings revegetation is a multidimensional issue, clearly notable demand exists for a study that provides a comprehensive understanding on the co-application impact on interrelated properties of physicochemical, biological, mineral nitrogen availability, metal immobilization, water-soil interactions, and impacts on plant cultivation and biomass production. This 8-month greenhouse study aimed at investigating the efficacy of co-application strategies targeting BS and carbon-rich amendments (BC or humic substances (HS)) to phytomanage a slightly alkaline Pb/Zn/Cu tailings with bioenergy crops (poplar, willow, and miscanthus). A complementary assessment linking revegetation effectiveness to ecosystem services (ES) provision was also included. Owing to their rich nutrient and organic matter contents, BS had the most pronounced influence on most of the measured properties including physicochemical, enzyme activities, NH 4 + -N and NO 3 - -N availability, immobilization of Zn, Cu, and Cd, and biomass production. Co-applying with BC exhibited efficient nutrient release and was more effective than BS alone in reducing metal bioavailability and uptake particularly Pb. Poplar and willow exhibited more superior phytostabilization efficiency compared to miscanthus which caused acidification-induced metal mobilization, yet BC and BS co-application was effective in ameliorating this effect. Enhancement of ES and substrate quality index mirrored the positive effect of amendment co-application and plant cultivation. Co-applying HS with BS resulted in improved nutrient cycling while BC enhanced water purification and contamination control services., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Water scarcity and low soil fertility severely constrain crop growth and sustainable agricultural productivity on the Tibetan Plateau. Organic amendments and ridge-furrow mulching system (RFMS) are widely used to improve soil moisture, soil structure, and crop production in arid and semi-arid areas. However, their combined effects on soil physicochemical properties and economic benefits of wolfberry (Lycium barbarum L.) on the Tibetan Plateau remain unclear. A two-year field experiment was undertaken to evaluate the combined effects of organic amendments and RFMS on soil water, soil structure, soil saturated hydraulic conductivity, soil organic carbon (SOC), total nitrogen (TN), and economic benefits on wolfberry. Four cultivation practices were established: traditional flat plot with mulching (FP), traditional flat plot with mulching and organic amendment (FPOA), ridge-furrow planting with mulching (RF), and ridge-furrow planting with mulching and organic amendment (RFOA). The organic amendment and RFMS treatments had higher soil water storage (SWS) and soil desiccation index (SDI) than the FP treatment in both growing seasons, especially at 20-60 cm soil depth. In addition, organic amendment significantly decreased soil bulk density by 6.4% and increased soil saturated hydraulic conductivity by 16.8% in the 0-60 cm soil layer, respectively, and improved the proportion of larger soil aggregates (0.02-2 mm) by 10.8% in the 0-40 cm soil layer. Furthermore, the RFOA treatment significantly improved SOC and TN contents at 0-60 cm soil depth by 47.7% and 19.4%, respectively, relative to FP. The measured soil properties were highly correlated with wolfberry yield and water use efficiency over 2 years. In particular, the RFOA treatment had higher crop yield and economic benefit than the other treatments due to the more favorable soil environment. Therefore, the RFOA treatment could be a sustainable and efficient cultivation practice for alleviating drought stress, improving soil properties, and increasing economic benefit on the Tibetan Plateau., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Pig manure (PM), wheat straw (WS), compost product (CP) and improved compost product (IC) are very important agricultural organic resources. In this study, their applicability as soil organic fertilizations (OFs) in terms of their properties and influence on soil properties through an incubation experiment and a field verification were evaluated. The property differences indicated that wheat straw has the highest C/N ratio, and compost products contain more aromatic compounds compared with pig manure and wheat straw. The results of incubation experiment showed that OFs promoted the carbon and nitrogen transformation driven by related microorganisms and their functional metabolisms. The PM treatment had the highest proportion of Labile organic carbon to soil organic carbon (LOC/SOC) and ratio of dissolved organic carbon to soil organic carbon (DOC/SOC), while WS treatment had the lowest values. The highest net N mineralization rate and nitrification rate was observed in the WS treatment, but the lowest amounts were under the PM treatment. Additionally, the similar findings were also obtained from the field examination. Therefore, compost products were more applicable in agricultural soil as OF insight from changes in carbon, nitrogen and microbial community. Furthermore, the result of UV-vision showed that the largest amount of aromatic structure was observed in IC relative to CP. It can be concluded that CP was more conducive to fix carbon and provide available nitrogen for crops among four OFs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

The role of organic amendments for natural degradation of aged persistent organic pollutants (POPs) in agricultural soils remains controversial. We hypothesised that organic amendments enhance bacterial activity and function at the community level, facilitating the degradation of aged POPs. An incubation study was conducted in a closed chamber over 12 months to assess the effects of selected organic amendments on extractable residues of aged dieldrin. The role of bacterial diversity and changes in community function was explored through sequenced marker genes. Linear mixed effect models indicated that, independent of amendment type, cumulative CO 2 release was negatively associated with decreases in dieldrin concentration, by up to 7% per µmol CO 2 -C respired by microorganisms. The addition of poultry litter led to the highest daily carbon mineralisation, which was associated with low dieldrin dissipation after 9 months. In comparison, biochar resulted in significant decreases in extractable dieldrin residues over time, which coincided with shifts towards aerobic, oligotrophic, gram-negative bacteria, some with dehalogenation metabolism, and with increased potentials for biosynthesis of membrane components such as fatty acids and high redox quinones. The results supported an alternative theory that labile carbon promoted blooms of copiotrophic growth, which suppressed the required community-level traits and oligotrophic diversity to degrade chlorinated pollutants., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Applying organic amendments to recover physical, chemical, and biological qualities of soil may enable recovery of soils degraded by mining in semiarid climates. This study's aim was to investigate the development and changes in the composition of fungal communities in restored soils with five different types of organic amendments (two types of vegetable compost and sewage sludge compost, and a mixture of both) compared with unamended soils and surrounding natural soils and to examine the relationships between the fungal taxa, the new physico-chemical and biological soil properties of technosoils after 18 months of restoration, and natural soils. Restoration improved soil quality and fungal diversity, placing these soils in an intermediate position between unrestored soils (with no fungi present) and undisturbed reference soils, which were the most fungal diverse. Sewage-treated soils and their mixtures showed high nitrogen and carbohydrate content as well as high basal respiration and fatty acid content, suggesting that they provided readily biodegradable organic matter. In contrast, greenhouse compost-treated soils showed high total organic carbon and polyphenol content, whereas garden compost-treated soils showed intermediate values. The biological soil properties of both composts showed were similar to those of the reference soils, suggesting that composts contained more resilient organic matter. Organic amendments of dissimilar origin caused significantly different fungal soil communities at the genus level among the restored soils. Results indicated that soil pH, electrical conductivity, total nitrogen content, soil basal respiration, fungi/bacteria-PLFA ratio, and dehydrogenase and β-glucosidase activities, together with Pearson's correlations, revealed that these properties and nutrient content (total organic carbon, C/N ratio, carbohydrates, and polyphenols) influenced 40 soil fungal taxa. Therefore, the organic amendments led to changes in soil properties that favoured plant cover by promoting the soil fungal community growth beneficial to the carbon cycle and symbiotic with plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The term "Total petroleum hydrocarbons" (TPH) is used to describe a complex mixture of petroleum-based hydrocarbons primarily derived from crude oil. Those compounds are considered as persistent organic pollutants in the terrestrial environment. A wide array of organic amendments is increasingly used for the remediation of TPH-contaminated soils. Organic amendments not only supply a source of carbon and nutrients but also add exogenous beneficial microorganisms to enhance the TPH degradation rate, thereby improving the soil health. Two fundamental approaches can be contemplated within the context of remediation of TPH-contaminated soils using organic amendments: (i) enhanced TPH sorption to the exogenous organic matter (immobilization) as it reduces the bioavailability of the contaminants, and (ii) increasing the solubility of the contaminants by supplying desorbing agents (mobilization) for enhancing the subsequent biodegradation. Net immobilization and mobilization of TPH have both been observed following the application of organic amendments to contaminated soils. This review examines the mechanisms for the enhanced remediation of TPH-contaminated soils by organic amendments and discusses the influencing factors in relation to sequestration, bioavailability, and subsequent biodegradation of TPH in soils. The uncertainty of mechanisms for various organic amendments in TPH remediation processes remains a critical area of future research., (Copyright © 2021 Elsevier B.V. All rights reserved.)