Organic Soil Amendments Research Articles

The Effects of Different Combinations of Cattle Organic Soil Amendments and Copper on Lettuce (cv. Rufus) Plant Growth

In modern agricultural production, cattle manure waste recovery is considered as a sustainable approach to agricultural waste management, reducing environmental pollution and chemical fertilizer use. This study aimed to investigate the effects of manure and digestate derived from a pilot-scale livestock waste-recycling system, in combination with a low copper concentration as a fungicide, on the physiological response of lettuce cv Rufus (Lactuca sativa L.) plants and the associated soil microbiome. A five-week microcosm experiment was conducted in a greenhouse under environmental conditions. Lettuce plant performance was assessed in terms of biomass, leaf area index, photosynthetic activity, chlorophyll measurements, lipid peroxidation, total phenolic content, and nutrient uptake. The results suggested that incorporating digestate into the potting soil mix significantly enhanced crop yields compared to the control and manure treatments. The soil microbial activity increased in the presence of fertilizers, improving the soil chemical and biological properties. The addition of copper negatively affected the growth and physiological performance of the lettuce plants under both the control and manure-treated conditions, except for those grown in the presence of digestate, where copper accumulation was reduced. These findings highlight the potential of growing horticultural crops using organic fertilization through livestock waste anaerobic digestate, establishing a waste-to-food recycling system.

Integrating waste valorization and symbiotic microorganisms for sustainable bioremediation of metal(loid)-polluted soils

Remediation strategies for metal(loid)-polluted soils vary among the wide range of approaches, including physical, chemical, and biological remediation, or combinations of these. In this study, we assessed the effectiveness of a set of soil remediation treatments based on the combined application of inorganic (marble sludge) and organic amendments (vermicompost, and dry olive residue [DOR] biotransformed by the saprobic fungi Coriolopsis rigida and Coprinellus radians) and inoculation with arbuscular mycorrhizal fungi (AMFs) (Rhizophagus irregularis and Rhizoglomus custos). The treatments were applied under greenhouse conditions to soil residually polluted by potentially toxic elements (PTEs) (Pb, As, Zn, Cu, Cd, and Sb), and wheat was grown in the amended soils to test the effectiveness of the treatments in reducing soil toxicity and improving soil conditions and plant performance. Therefore, we evaluated the influence of the treatments on the main soil properties and microbial activities, as well as on PTE availability and bioaccumulation in wheat plants. Overall, the results showed a positive influence of all treatments on the main soil properties. Treatments consisting of a combination of marble and organic amendments, especially biotransformed DOR amendments, showed the greatest effectiveness in improving the soil biological status, promoting plant growth and survival, and reducing PTE availability and plant uptake. Furthermore, AMF inoculation further enhanced the efficacy of DOR amendments by promoting the immobilization of PTEs in soil and stimulating the phytostabilization mechanisms induced by AMFs, thus playing an important bioprotective role in plants. Therefore, our results highlight that biotransformed DOR may represent an efficient product for use as a soil organic amendment when remediating metal(loid)-polluted soils, and that its application in combination with AMFs may represent a promising sustainable bioremediation strategy for recovering soil functions and reducing toxicity in polluted areas.

Using organic amendments in disturbed soil to enhance soil organic matter, nutrient content and turfgrass establishment

Disturbed soils, including manufactured topsoils, often lack physical and chemical properties conducive to vegetation establishment. As a result, efforts to stabilize disturbed soils with vegetation are susceptible to failure. Urban organic waste products such as wood mulch, composted leaf and yard waste, and biosolids are widely distributed as organic amendments that enhance sustainability and plant establishment. Correct use can be determined by examining soil properties such as pH; the concentration of soluble salts (SS); and plant available nutrients — particularly N, C and P; as well as root and shoot growth. This research examined the effects of three typical organic amendments on fertility, establishment, and nutrient loss. A manufactured topsoil was used as the base soil for all treatments, including a control unamended soil (CUT), and soil amended with either mulch (MAT), composted leaf and yard waste (LAT), or biosolids (BAT). A 2 % organic matter concentration increase was sought but not achieved due to difficulty in reproducing lab results at a larger scale. Results showed that LAT improved soil fertility, particularly N-P-K concentrations while maintaining a good C:N ratio, pH, and SS concentration. BAT was the most effective at enhancing shoot growth but results suggest that improved growth rates could result in increased maintenance. Additionally, biosolids were an excellent source of nutrients, especially N-P-K and S, but diminished root growth and N leachate losses indicate that N was applied in excess of turfgrass requirements. Therefore, biosolids could be used as fertilizer, subject to recommended rates for turfgrass establishment to prevent poor root growth and waterborne N pollution. To ensure establishment efforts are successful, MAT is not recommended without a supplemental source of soluble N. Altogether, study results and conclusions could inform others seeking to improve specifications for disturbed soil where turfgrass establishment is needed to stabilize soil.

Nitrogen fertilizer replacement value of stockpiled and rotted dairy cattle manures for corn (Zea mays L.) from a long-term study

Context or problemAnimal manure is an excellent renewable source of plant nutrients, but the correct quantification of nutrient equivalents is affected by manure type and application rate as well as weather conditions that impact crop yields Objective or research questionThe objectives from a 32-year field experiment were to (1) compare the effects of mineral N fertilization and solid dairy cattle manure on corn grain yield; (2) determine the manure N fertilizer replacement value (NFRV), and (3) quantify environmental factors, mainly the impact of total precipitation during the critical period (silking) on corn yield and manure NFRV. MethodsA field experiment under continuous corn with annual manure application was conducted over 32 years in Ottawa, Ontario, Canada. Corn yield data were categorized into low, intermediate, and high N response groups. ResultsOn an equivalent amount of manure organic N basis, NFRVs were, on average, 0.38 (±0.02) for stockpiled manure (SM) and 0.27 (±0.02) for incompletely composted or rotted manure (RM), with a wide range of 0.12 (±0.02), 0.28 (±0.02), and 0.37 (±0.04) for RM, and 0.16 (±0.04), 0.39 (±0.03), and 0.48 (±0.04) for SM under the low, intermediate, and high N response conditions, respectively. Supplementing 100 kg synthetic fertilizer N ha−1 in low RM (50 Mg ha−1 fresh weight; f.w.), and 50 kg fertilizer N ha−1 in high RM (100 Mg ha−1 f.w.) application rates decreased NFRVs under low and intermediate N response conditions, whereas the addition of similar synthetic N in the corresponding SM rates reduced NFRVs only under low N response conditions. ConclusionsBased on the 32-year long-term study, we documented that the maximum economic synthetic N fertilizer rates for continuous corn cropping varied from 117 to 179 kg N ha−1 under the low N response, from 127 to 283 kg N ha−1 under the intermediate N response, and from 227 to 289 kg N ha−1 under the high N response conditions. The NFRVs of solid cattle manures varied according to corn yield-N response levels. Implications or significanceOur findings showed that the response of corn yields to manure NFRV depends on the level of yield-N response and climatic conditions. It also indicated the importance of soil organic amendments for improving the climate resilience of corn production, while simultaneously meeting the demand for more sustainable nutrient management of soil resources.

Optimizing the water-ecosystem-food nexus of avocado plantations

Climate change, food and water security and ecosystem sustainable management are tightly interlinked and require holistic approaches to achieve solutions that do not impact adversely one-another. The objective of this work was to conduct studies, collect data and assess the Water-Ecosystem-Food (WEF) nexus in avocado plantations in the Mediterranean region systematically to minimize the environmental footprint while maximizing the benefits for the farmer and the environment. The study includes two distinct experiments; the first addresses the impact of soil organic amendments addition to optimize the WEF nexus and the second monitors experimentally crop water needs and thus illustrates how irrigation practices aided by technology can reduce substantially water consumption. The results showed that organic amendments addition improves fertility, nutrient sequestration and structure but only had a weak effect on biodiversity by increasing the number of unique species. For the development of an efficient irrigation system it is necessary to determine the radius around the tree, the depth of the roots and the time required for the water to reach the active root zone to determine the amount and duration of irrigation. In this way sufficient water will be added to replenish the soil moisture deficit created due to the evapotranspiration. HYDRUS-1D model was used to simulate soil moisture and the hydrologic budget of an avocado tree located in Koiliaris river basin and confirm the percolation losses to groundwater. The results of this study showed that the actual irrigation needs of avocados in the Mediterranean is less than 2,000 m3/ha which is 75% less than what is recommended and could become the primary measure for the mitigation of climate change impacts especially in semi-arid regions such as the Mediterranean.

Response of ectomycorrhizal fungi to full and selective removal of an invasive tree in riparian woodland

The Brazilian pepper tree (Schinus terebinthifolius) is an invasive species that requires significant disturbance to eradicate. Previous studies have identified associations between the Brazilian pepper tree and ectomycorrhizal fungi (EMF). However, limited research has explored the connection between disturbance from removal and the effect on EMF. This study investigated the sensitivity of EMF and the broader fungal community to the full and selective removal of the Brazilian pepper tree. During the selective removal of Brazilian pepper tree, we examined the mycorrhizal community of the Arroyo willow (Salix lasiolepis) to assess the influence of the restoration disturbance on native species. We used ITS2 sequencing to identify the EMF present during the restoration. Our expectation was that both removal efforts would reduce the presence of EMF. Contrary to our predictions, full removal increased EMF richness and relative abundance in the soil. As anticipated, selective removal reduced the richness and relative abundance of EMF associated with soil. Selective removal led to a decrease in the richness of EMF in arroyo willow roots with no effect on relative abundance. Moreover, fungal community composition in soil and roots shifted significantly during selective and full removal. However, the community composition of EMF, specifically, remained constant across treatment types. During full removal efforts, the application of organic soil amendments may have contributed to the increase in the diversity and relative abundance of EMF. Selective removal will require additional measures, such as soil amendments, to curtail the loss of EMF.

Maize straw increases while its biochar decreases native organic carbon mineralization in a subtropical forest soil

Organic soil amendments have been widely adopted to enhance soil organic carbon (SOC) stocks in agroforestry ecosystems. However, the contrasting impacts of pyrogenic and fresh organic matter on native SOC mineralization and the underlying mechanisms mediating those processes remain poorly understood. Here, an 80-day experiment was conducted to compare the effects of maize straw and its derived biochar on native SOC mineralization within a Moso bamboo (Phyllostachys edulis) forest soil. The quantity and quality of SOC, the expression of microbial functional genes concerning soil C cycling, and the activity of associated enzymes were determined. Maize straw enhanced while its biochar decreased the emissions of native SOC-derived CO2. The addition of maize straw (cf. control) enhanced the O-alkyl C proportion, activities of β-glucosidase (BG), cellobiohydrolase (CBH) and dehydrogenase (DH), and abundances of GH48 and cbhI genes, while lowered aromatic C proportion, RubisCO enzyme activity, and cbbL abundance; the application of biochar induced the opposite effects. In all treatments, the cumulative native SOC-derived CO2 efflux increased with enhanced O-alkyl C proportion, activities of BG, CBH, and DH, and abundances of GH48 and cbhI genes, and with decreases in aromatic C, RubisCO enzyme activity and cbbL gene abundance. The enhanced emissions of native SOC-derived CO2 by the maize straw were associated with a higher O-alkyl C proportion, activities of BG and CBH, and abundance of GH48 and cbhI genes, as well as a lower aromatic C proportion and cbbL gene abundance, while biochar induced the opposite effects. We concluded that maize straw induced positive priming, while its biochar induced negative priming within a subtropical forest soil, due to the contrasting microbial responses resulted from changes in SOC speciation and compositions. Our findings highlight that biochar application is an effective approach for enhancing soil C stocks in subtropical forests.

A sustainable approach to improving agrifood production: getting the balance right between organic soil amendments and chemical fertilizers

PurposeWe analyzed the effects of different combinations of organic soil amendments (OSAs) and chemical fertilizers on agrifood production, focusing on banana yields in China, the second-largest producer of bananas globally.Design/methodology/approachWe computed these combinations by dividing the expenditures on OSAs by those on chemical fertilizers and called them OSA-CF ratios. First, we classified farmers based on quintiles of expenditures on chemical fertilizers. Then, we studied the association between OSA-CF ratios and banana yields for each quintile. We also considered an alternate specification in which farmers were grouped along the OSA-CF ratio continuum. The first group comprised farmers not using OSAs. Their OSA-CF ratio was zero. Farmers applying low, medium, and high OSA-CF ratios constituted groups two, three, and four; the groups were delineated based on the OSA-CF ratio tertiles, and the associations between tertiles of OSA-CF ratios and banana yields for each quintile were analyzed. The data used in this study were collected by surveying 616 households in three major banana-producing provinces (Guangdong, Hainan, and Yunnan) of China. Standard linear regressions and the two-stage predictor substitution method were employed to complete the analysis.FindingsThere were variations in the effects of OSA-CF ratios on banana yields obtained by farmers iifferent quintiles. For the first and second quintiles, low, medium, and high OSA-CF ratios improved banana yields relative to not using OSAs. For farmers in the first quintile using only chemical fertilizers, applying a low OSA-CF ratio was associated with an improvement of 792 kg/mu in banana yields. For their counterparts in the second quintile, the same transition was associated with a gain of 534 kg/mu. For the fifth quintile, comprising farmers spending 320 yuan/mu or more on chemical fertilizers, applying a high OSA-CF ratio instead of using only chemical fertilizers was associated with a 401 kg/mu decline in banana yields. Even so, for this group, no differences were observed between the yields of farmers not applying OSAs and those using low and medium OSA-CF ratios.Practical implicationsBanana farmers in southern China, using only chemical fertilizers, can improve yields by combining them with OSAs if their chemical fertilizer expenditures are less than 66.67 yuan/mu. Those using only chemical fertilizers and spending between 68 yuan/mu and 300 yuan/mu on them can maintain yields by applying OSAs in conjunction with chemical fertilizers. However, yields may decline for farmers using only chemical fertilizers and spending 320 yuan/mu or more on them if they incorporate OSAs such that the OSA-CF ratio reaches 0.78 or higher. Overall, combining OSAs with chemical fertilizers can improve yields while attenuating the adverse effects of chemical fertilizers on the environment. Policymakers should inform farmers of these benefits and accelerate the transition to sustainable agriculture through educational and awareness programs.Originality/valueFarmers apply OSAs such as organic fertilizers and farmyard manure to adjust and remedy soil nutrition to improve farm productivity. However, little is known about how combining OSAs with chemical fertilizers affects banana yields. This study provided the first attempt to explore the associations between OSA-CF ratios and banana yields using cross-sectional data on farming households.

A Comprehensive Perception of Biological Control Potential of Endophytes and Quality Refinement of Lagenaria siceraria.

Agriculture and livestock management practices known as organic farming rely more on internal processes than external inputs. Natural environments depend heavily on diversity, and organic farming incorporates both the stated purpose of fostering diversity as well as the use of diversity as a management tool. A more complete understanding of agriculture in terms of agro-ecology has begun to be questioned by the traditional reductionist approach to the study of agriculture. Therefore it is necessary to be aware more about the significance of microbes in processes including soil growth, plant nourishment, and the eradication of plant disease, pest, and weeds. In this study, fluorescent Pseudomonas strain (EFP56) and Trichoderma harzianum were studied for antifungal and antibacterial activity against four common root rot fungi and four common laboratory bacteria in vitro experiments. Furthermore, soil-borne disease surveillance and nutritional quality of Lagenaria siceraria, fluorescent Pseudomonas strain (EFP56) and Trichoderma harzianum were combined with neem cake and cotton cake to check their efficacy. Through the application of organic soil amendments in combination with biocontrol agents improved the quality of vegetables and their nutritional value by raising their polyphenol, carbohydrate, and protein content as well as enhancing antioxidant scavenging status. The experiments were conducted in pots and in fields to confirm their efficacy rate. The final outcomes also revealed greater induction of defense system, disease lessening and enriched fruit quality. Consortium of neem cake and cotton cake with bio-stimulants can regulate biotic as well as abiotic stress.

Improving stormwater infiltration and retention in compacted urban soils at impervious/pervious surface disconnections with biochar

Urban development often results in compacted soils, impairing soil structure and reducing the infiltration and retention of stormwater runoff from impervious features. Biochar is a promising organic soil amendment to improve infiltration and retention of stormwater runoff. Soil at the disconnection between impervious and pervious surfaces represents a critical biochar application point for stormwater management from urban impervious features. This study tested the hypothesis that biochar would significantly improve water retention and transmission at four sites, where varying percentages (0%, 2%, and 4% w/w) of biochar were amended to soils between impervious pavement, and pervious grassed slopes. Field-saturated hydraulic conductivity (Ksat) and easily drainable water storage capacity were monitored at these sites for five months (two sites) and 15 months (two sites). At the end of the monitoring periods, the physical, chemical, and biological properties of each site's soil were assessed to understand the impact of biochar on soil aggregation, which is critical for improved soil structure and water infiltration. Results indicated that the field Ksat, drainable water storage capacity, and plant available water content (AWC) were 7.1 ± 3.6 SE, 2.0 ± 0.3 SE, and 2.1 ± 0.3 SE times higher in soils amended with 4% biochar, respectively, compared to the undisturbed soil. Factor analysis elucidated that biochar amendment increased the organic matter content, aggregate mean weight diameter, organo-mineral content, and fungal hyphal length while decreasing the bulk density. Across the 12 biochar/soil combinations, the multiple linear regression models derived from factor analysis described the changes in Ksat and AWC reasonably well with R2 values of 0.51 and 0.71, respectively. Using soil and biochar properties measured before biochar addition, two recent models, developed from laboratory investigations, were found helpful as screening tools to predict biochar's effect on Ksat and AWC at the four field sites. Overall, the findings illustrate that biochar amendment to compacted urban soils can significantly improve soil structure and hydraulic function at impervious/pervious surface disconnections, and screening models help to predict biochar's effectiveness in this context.

Eco-Sustainability of Soils in Baby-Leaf Crop Systems under Tunnel through the Application of C-Rich Inputs: Towards Combating Soil Degradation

Fresh-cut leafy vegetables are produced in Southern Italy in very intensive crop systems under tunnel greenhouses in which continuous cropping has triggered soil organic carbon (SOC) depletion and the risk of degradation of soil fertility. A two-year trial of soil organic amendment was carried out on a private farm producing baby-leaf crops on a very poor OC soil (<1%). Biowaste compost, two types of olive pomace composts and buffalo manure were compared to evaluate their ability to recover a positive SOC balance and sustain crop growth and yield. The effects on soil health and crop system were studied by measuring different aspects such as SOC stock change and SOC sequestration rate, soil microbial biomass and nine enzyme activities, yields of rocket and concentration of nitrates in leaves. Soil amendments were distributed once a year at doses of 15 and 30 Mg ha−1 as fresh matter without integration of mineral fertilizers. In our study, the SOC stock improved in the amended soils in a range of 4–6 Mg ha−1, except for dose 30 of buffalo manure, with the highest values where biowaste compost was applied. Our data showed an increase in biological parameters in all the amended soils with respect to Control. In soil amended with olive pomace, however, compost mineralization rates likely did not match crops’ nutrient needs so the yields of rocket were lower than with the biowaste compost and buffalo manure. Biowaste compost showed the best results as it balanced the best C conversion efficiency, the higher increment of SOC and yields of rocket.

Improving marketable yield and phytochemical characteristics of N-fertilized tomato fruits with soil organic amendments through Azolla

ABSTRACT There is a growing demand for organic vegetable products. Increasing the marketable yield and quality of tomatoes through the use of optimal organic and inorganic fertilizers is a critical agronomic measure for crop productivity and soil health. However, little is known about the effects of Azolla on tomato productivity, fruit quality and soil organic changes. The aim of this study was to compare the effects of organic and inorganic fertilization on marketable yield and quality characteristics of tomato fruits. A pot experiment was conducted with four concentrations of Azolla and nitrogen in a completely randomized design. The results showed that Azolla has the potential to replace nitrogen and has a significant impact on fruit quality. The interactions of Azolla and nitrogen on the number of clusters per plant, the number of flowers per cluster, the proportion of fruit set, the number of fruits per cluster and the marketable fruit yield were significant. It can be concluded that the combination of Azolla and inorganic nitrogen fertilizer linearly increased the marketable yield and quality of tomato fruits.

Effects of Biochar and Compost on Turfgrass Establishment Rates

Organic soil amendments are a sustainable option for modifying soil structure and improving plant performance in the face of abiotic stressors such as drought and soil salinity. Of these amendments, biochar and compost have the added benefits of carbon sequestration and waste recycling. Establishment studies were conducted on tall fescue (Festuca arundinacea Schreb.) (syn., Schedonorus arundinaceus (Schreb.) Dumort and Lolium arundinaceum (Scop.) Holub) to assess the potential inhibition of establishment by compost and biochar products. Both green waste and biosolid compost impaired establishment rates, while biochar did not. In the field study, the green waste treatments were slower to reach 50% coverage than the untreated control or when biochar was added to the soil, but all treatments reached 75% and final coverage at a similar rate. Field application of compost had a positive effect on final root length and volume but a negative effect on tall fescue roots in the greenhouse. The negative effect of higher salts and volatiles in the biosolids compost was reduced when biosolids and biochar were incorporated into the soil simultaneously. This work represents one of the only large-scale field studies on turfgrass establishment comparing the impact of biochar and compost products on turfgrass establishment.

Dynamic population changes during a bioaugmented sewage sludge composting process: Improvement of pharmaceutical active compounds degradation and conversion into an organic soil amendment

Bioaugmentation has resulted in an interesting tool to improve the remotion of emerging contaminants through composting technologies in sewage sludge, whose microbial population dynamics might play a critical role during degradation. It was hypothesized that the two-step bioaugmentation-composting technology can guarantee both, an effective addition of specific inoculants and the enhancement of the degradation activity in relation to their application and their interactions with indigenous communities. Following this hypothesis, this study aimed to define the changes of fungal and bacterial populations during microbial bioaugmentation of sewage sludge with two different inoculants (Penicillium oxalicum XD 3.1 and an enriched consortium) and throughout the composting process of the bioaugmented sludge. To do so, microbial DNA was obtained from the natural consortium and from the composite samples (at key stages of the process). The amplicon sequencing of 16S rRNA genes and internal transcribed spacer (ITS) region for bacteria and fungi was then performed using an Illumina Platform. The results highlighted the importance of the inoculation per se plays an important role in determining the success of microbial inoculation during the two-step composting. Thus, correctly addressing the degradation potential as well as the competitive ability of the inoculants to persist alongside native populations by enhancing the abundance, diversity and richness of fungi and bacterial taxa related with degradation processes. Moreover, various physicochemical parameters altered by the bioaugmentation equally explained the microbial diversity changes. Redundancy analyses of β-diversity revealed the asynchronous interaction with all physicochemical parameters that varied according to the composting stage.

Enhancing Soil Aggregate Stability and Organic Carbon in Northwestern China through Straw, Biochar, and Nitrogen Supplementation

Enhancing soil stability through the incorporation of straw and biochar is well documented. Nevertheless, the combined impact of straw, biochar, and nitrogen supplementation on soil aggregates and organic carbon still needs to be explored, with limited attention given to various sieving methods in the existing literature. Therefore, the current experiment used four sieving methods—routine wet sieving (RoutW), fast-wetting sieving (FastW), slow-wetting sieving (SlowW), and wetting–stirring sieving (WetS)—to investigate the effects of adding straw (0 or 4.5 t ha−1), biochar (from maize straw, 0 or 15 t ha−1), and N (0 or 100 kg ha−1) on soil aggregate stability and soil organic C in silt–loam soil of rainfed farmland in northwest China. The field experiment was started in 2014; soil samples were collected in 2021. The results revealed that straw returned, biochar, and N addition significantly increased soil mean weight diameter (MWD) and soil organic C (SOC). Compared to CN0 (zero-amendment) plots, straw returned with nitrogen addition (SN100) significantly increased the MWD of aggregates by 130.3% (RoutW), 121.66% (FastW), 73.94% (SlowW), and 91.78% (WetS) in the 0–30 cm soil layer. The addition of biochar and nitrogen (BN100) treatment showed the most significant effects on the relative slaking index (RSI), relative mechanical breakdown index (RMI), and SOC; compared with CN0 treatment, BN100 plots can reduce RSI and RMI by 42.90% and 54.66% and increase SOC by 53.27% for all soil layers. Therefore, adding organic materials with N can enhance the stability of soil aggregates and SOC of silt–loam soils in northwest China. Integrating biochar as an organic soil amendment in the agricultural practices of northwest China presents a multifaceted solution that addresses soil health, crop productivity, and environmental sustainability. The current study provides valuable insights that support adopting this innovative approach, paving the way for future sustainable agricultural practices that can benefit both the region and the global community.

Challenges in Sustainable Agriculture—The Role of Organic Amendments

Soil degradation threatens global food security and environmental sustainability, necessitating effective soil management strategies. This review comprehensively examines the impact of organic soil amendments on soil quality and productivity across various soil types and climatic conditions. A review of significant research related to organic amendments was performed using encompassed data from online search engines for studies published up until 31 December 2023. Despite their heterogeneity and use of varying methodologies, the data were narratively synthesized, providing a comprehensive understanding of amendment-induced changes in the chemical and physical properties of soil and the effectiveness of restoration on soil degradation. Organic amendments, including compost, vermicompost, biochar, and pomace, are pivotal in enhancing soil quality by increasing soil organic matter content, fostering aggregate formation, and improving soil structure in the short term. They positively influence water retention capacity, pH levels, nutrient availability, and carbon sequestration. In several studies, amendment-induced changes were absent, indicating that the effects of amendments vary depending on soil texture, application rates, and cropping systems, which emphasizes the need for tailored, sustainable soil management practices. This study concludes that organic amendments are a promising option for structure improvement and organic matter accumulation. It further suggests that an approach that integrates various methods is essential in order to meet desirable soil quality and retain agricultural productivity and offers valuable insights and recommendations for policymakers, practitioners, and researchers. Organic amendments can improve soil ecosystem services and contribute to climate change adaptation. In the future, more attention should be directed to tillage management and soil amendment interaction, as well as their effectiveness over specific periods of time.

SPENT BLEACHING EARTH-BIOPROCESS (SBE) CHARACTERISTICS AGAINST INDONESIAN NATIONAL REGULATION FOR TOXIC-HAZARD WASTE AND SOIL AMENDMENT

<p>Currently, the palm oil industry disposes the Spent Bleaching Earth (SBE) to the land-field without a proper treatment process. Some peoples argue that the SBE still in high oil content and will pose an environmental problem due to hazardous content and it will easily catch fires. One possible solutions is optimizing SBE for land restoration, which could also be enhancing livelihood and reducing pollution. This paper identifies the SBE-bioprocess according to the Indonesian National Regulation for toxic-hazard waste and soil rehabilitation. SBE-bioprocess testing was conducted as toxic-hazard waste both on TCLP organic and anorganic form also as a soil amendment criteria both certain function and organic. Research shows that the SBE-bioprocess could not be categorized as toxic-hazard waste due to very low value of toxic and hazard compounds. Additional C-organic is important before using it as an organic soil amendments. Lab test shows that SBE-bioprocess is high value of CEC, then could be developed for specific function of soil amendments.</p>

Effects of Land Preparation Method and Organic Soil Amendment on Soil Properties, Growth and Yield of Maize (Zea mays)

Effects of Land Preparation Method and Organic Soil Amendment on Soil Properties, Growth and Yield of Maize (Zea mays)

Biochelates from Spent Coffee Grounds Increases Iron Levels in Dutch Cucumbers but Affects Their Antioxidant Capacity.

Spent coffee grounds (SCG) are a type of food waste and are produced in abundance around the world. However, their utilization as a soil organic amendment is challenging due to their phytotoxic effect. In the present work, the impact of agronomic biofortification on Dutch cucumbers was investigated using different chemically modified SCG and analyzing their effects on iron contents, their capacity for releasing antioxidants, and the production of short-chain fatty acids after in vitro digestion-fermentation. The results indicated variations in the iron contents and chemical compositions of cucumbers according to the treatment groups. Functionalized and activated hydrochar from SCG increased Fe levels in cucumbers. Although activated hydrochar obtained at 160 °C and functionalized with Fe showed the highest iron supply per serving, differences in antioxidant capacity and short-chain fatty acid production were observed between the groups. It is concluded that growing conditions and the presence of iron may significantly influence the contribution of these cucumbers to the dietary intake of nutrients and antioxidants, which could have important implications for human health and nutrition.

Zn Biofortification of Dutch Cucumbers with Chemically Modified Spent Coffee Grounds: Zn Enrichment and Nutritional Implications.

Spent coffee grounds (SCGs) are a food waste with a large generation around the world. However, their utilization as a soil organic amendment is difficult due to their phytotoxic effect. In the present work, the impact of agronomic biofortification on Dutch cucumbers was studied by using different chemically modified SCGs, analyzing their effects on Zn content, the release of antioxidant capacity and the production of short-chain fatty acids after in vitro digestion-fermentation. The results indicated variations in the Zn content and chemical composition of cucumbers according to the treatment groups. The functionalized with Zn and activated SCGs were able to increase Zn levels in cucumbers. Meanwhile, the activated hydrochar obtained at 160 °C and the activated and functionalized with Zn SCGs showed the highest Zn supply per serving. Differences in the antioxidant capacity and short-chain fatty acid production were observed between the groups. It is concluded that the growing conditions and the presence of Zn may significantly influence the contribution of these cucumbers to the dietary intake of nutrients and antioxidants, which could have important implications for human health and nutrition.