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The aim of this research was to determine the impact of composted mushroom substrate and composted municipal waste on the quality and yield of Miscanthus sinensis Andersson biomass. The plant was grown on anthropogenic soil, cultured earth type and hortisol subtype, with a pH of 6.81. Before planting rhizomes, experimental plots were treated with composted mushroom substrate and composted municipal waste, applied separately or in combination, each dose introducing 170 N kg·ha−1 to the soil. During the experiment, observations of plant development and growth were carried out, and the yield was determined. Each growing season's measurements were taken of the grass height, the number and diameter of stems and the number of leaf blades and of nodes per stem. In order to determine the level of plant stress, relative chlorophyll content and chlorophyll fluorescence parameters were determined. The measurements were carried out in a non-invasive way, using the SPAD-502 chlorophyll meter and OS30p+ plant stress meter. For the research hypothesis, it was assumed that the one-time addition of composted mushroom substrate and composted municipal waste to the soil would increase yields. The experiment also aimed to assess the impact of both types of compost on the yield and morphological characteristics of Miscanthus sinensis. Its yields increased steadily, and, in the third year of cultivation, were higher by 52%. The highest average yields were noted on plots fertilized only with composted mushroom substrate (KPP100%), with 8.44 Mg·ha−1 DM, and with compost from municipal waste (KOM100%), with 7.91 Mg·ha−1 DM. The experience presents a solution to the problem of increasing amounts of organic waste and represents an improvement in cultivation techniques to increase crop yields, improve their quality and increase resistance to biotic and abiotic stress. This paper highlights the possibility of applying environmentally friendly organic waste materials to energy crops used as a sustainable energy source. [ABSTRACT FROM AUTHOR]

The objective of the present study was to investigate the impact of MgO 0.5 g/kg loaded in different organic waste materials on the properties of the modified biochars obtained. The waste materials included tea waste, wood waste, water chestnut peel, and pomegranate peel, which were used to create tea waste MgO-modified biochar (TWMgO-MBC), wood waste MgO-modified biochar (WSMgO-MBC), water chestnut peel MgO-modified biochar (WCMgO-MBC), and pomegranate peel MgO-modified biochar (PPMgO-MBC). All the MgO-modified biochars were prepared at 600 °C for 2 h and applied at 0.5 and 1% doses for the immobilization of Ni, Cu, Pb, and Cr in stone crushing and mining-polluted soil and the reduction in their uptake by pearl millet (Pennisetum glaucum) plant. The greatest fresh and dry biomasses were observed at 45.04% and 31.29%, respectively, with the application of TWMgO-MBC 1% in stone-crushing-polluted soil. The highest degree of immobilization of Ni (76.67%) was observed for the WSMgO-MBC 1% treatment, Cu (73.45%) for WCMgO-MBC 1%, Pb (76.78%) for WSMgO-MBC 1%, and Cr (70.55%) for WCMgO-MBC 1%, in comparison with the control. The maximum uptake of Ni, Cu, Pb, and Cr in the shoot of pearl millet was reduced by 78.43% with WSMgO-MBC 1%, 75.06% with WSMgO-MBC 1%, 90.81% with WCMgO-MBC 1%, and 85.71% with WSMgO-MBC 1% as compared with the control. The greatest reduction in Ni, Cu, Pb, and Cr in the root of pearl millet was observed at 77.81% with WSMgO-MBC 1%, 68.09% with WCMgO-MBC 1%, 84.03% with WCMgO-MBC 1%, and 88.73% with WCMgO-MBC 1%, in comparison with the control. The present study demonstrated that the TWMgO-MBC 1% treatment was highly effective for improving plant growth, while the WSMgO-MBC 1%, and WCMgO-MBC 1% treatments were found to be highly effective for immobilizing heavy metals in polluted soils, thus facilitating safe crop cultivation. Future studies should concentrate on the long-term application of MgO-modified biochars for the remediation of multimetal-polluted soils. [ABSTRACT FROM AUTHOR]

Frass generated during the production of black soldier fly larvae is attracting the interest of scientists and horticultural producers because it is a material made from the biotransformation of organic waste, it contains several nutrients that can be used by plants, and it has a biostimulant capacity that has become a recent focus. Thermal composting is a stabilization process that improves the physical and chemical properties of treated wastes, allowing better performance in plants compared to the waste in its fresh state. In this research, thermocomposted frass was evaluated as a germination substrate for kale seeds (Brassica oleracea). To achieve this, the phytotoxicity of increasing concentrations of frass was evaluated by examining the germination of kale seeds, and seedlings were grown for 30 days in germination substrates mixed with 20, 40, 60, 80, and 100% frass under greenhouse conditions. The treatment with 20% frass showed the highest values of seedling height, stem diameter, number of leaves, length and width of the first true leaf and length and width of cotyledons, and reduced the contents of phenols, tannins and antioxidants. However, the content of flavonoids increased compared to the control and the rest of the mixtures. [ABSTRACT FROM AUTHOR]

Nitrogen loss is an unavoidable problem during composting processes, and the ammonia oxidation process significantly affects nitrogen transformation. The objective of this study was to evaluate nitrogen transformation when garbage enzyme (GE), biochar (BC), pelelith (PL) and combinations thereof were added during sewage sludge composting. Meanwhile, the succession of ammonia-oxidizing bacteria (AOB) and archaea (AOA) were also explored via quantitative polymerase chain reaction and high-throughput sequencing. The results showed that GE + BC and GE + PL treatments decreased ammonia (NH3) formation by 23.8% and 8.3%, and that of nitrous oxide (N2O) by 25.7% and 26.3% relative to the control, respectively. Simultaneously, the GE, GE + BC, and GE + PL treatments boosted the succession of AOA and AOB, and increased the activities of ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO) activities and the gene copies of AOA and AOB. The AMO activities, NH4-N, NO3-N, and C/N, significantly affect AOA and AOB community structures. The network analysis predicted that the AMO and HAO were secreted mainly by the unclassified_Archaea and norank_Crenarchaeota, whereas it also showed that the GE + BC improved microbial associations with AOA, enzymatic activity, and environmental factors. Thus, the addition of garbage enzyme and biochar appears to be a promising mitigation strategy to reduce nitrogen losses during the composting process. [ABSTRACT FROM AUTHOR]

The production of mineral fertilisers relies heavily on mineral deposits that are becoming depleted or is based on processes that are highly energy demanding. In this context, and in line with the circular economy and the European Green Deal, the recovery of nitrogen (N), phosphorus (P), and potassium (K) from organic wastes using chemical technologies is an important strategy to produce secondary raw materials for incorporation into mineral fertilisers, partially replacing the traditional sources of N, P, and K. However, there are very few studies on the agronomic and environmental effects of such substitution. The aim of this work was to evaluate plant growth under microcosm conditions and the effect on the soil microbiome of mineral fertilisers in which part of the N, P, or K content comes from bio-based materials (BBMFs), namely ash, struvite, and a patented chemical process. The crop was maize, and a metataxonomic approach was used to assess the effect on the soil microbiome. The BBMF treatments were compared with a control treated with a conventional mineral fertiliser. The conventional fertiliser performed significantly better than the bio-based fertilisers in terms of maize biomass production at the first sampling point 60 days after sowing (DAS), but at the last sampling point, 90 DAS, the BBMFs showed comparable or even better biomass production than the conventional one. This suggests that BBMFs may have a slightly slower nutrient release rate. The use of fertiliser, whether conventional or BBMF, resulted in a significant increase in microbiome biodiversity (Shannon index), while it did not affect species richness. Interestingly, the use of fertilisers modulated the composition of the bacterial community, increasing the abundance of beneficial bacterial taxa considered to be plant-growth-promoting bacteria, without significant differences between the conventional mineral fertilisers and the BBMFs. The predominance of PGPRs in the rhizosphere of crops when BBMFs are used could be part of the reason why BBMFs perform similarly or even better than conventional fertilisers, even if the rate of nutrient release is slower. This hypothesis will be tested in future field trials. Thus, BBMFs are an interesting option to make the food chain more sustainable. [ABSTRACT FROM AUTHOR]

Nitrogen loss is an unavoidable problem during organic waste composting, while exogenous microbial inoculation is a promising strategy for reducing nitrogen loss and improving compost quality. This study was designed to probe available nitrogen levels, bacterial community composition, and the levels of nitrogen functional genes present when composting cattle manure with or without the addition of Bacillus coagulans X3. Bacterial supplementation was associated with the prolongation of the thermophilic stage and improved maturity of the resultant compost. At the maturity stage, samples to which B. coagulans X3 had been added exhibited significant increases in ammonium nitrogen, nitrate nitrogen, and total nitrogen levels. The dominant bacterial phyla observed in these composting samples were Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteriota, and Chloroflexi. B. coagulans X3 addition resulted in significant increases in relative Firmicutes abundance during the thermophilic and cooling stages while also increasing amoA and nosZ gene abundance and reducing nirS gene levels over the course of composting. Together, these data suggest that B. coagulans X3 supplementation provides an effective means of enhancing nitrogen content in the context of cattle manure composting through the regulation of nitrification and denitrification activity. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) has the potential to be a sustainable and environmentally beneficial approach for organic waste treatment. It is likely that HTC product use will dictate the viability of large-scale HTC facilities; therefore, understanding the viability and environmental implications associated with HTC product valorization pathways is critical. The overall goal of this review is to gain an understanding of how HTC product valorization is currently being modeled in life cycle assessment studies, and to use such information to assess current research and/or data needs associated with product valorization. To accomplish this, a review of existing HTC literature was conducted and used to assess the current state of knowledge surrounding the environmental implications of HTC product use. From this review of the literature, it is clear that potential exists for HTC product valorization. To realize this potential in a full-scale application, research gaps and data needs were identified that included a system-level integration to evaluate location-specific information as well as more extensive characterization of the impact of HTC product properties on valorization impacts. [ABSTRACT FROM AUTHOR]

Composting is one of the best organic waste management techniques, with zero waste; however, it generates environmental impacts. The objective of this study was to evaluate the emission of NH3, N2O, CO2, and CH4 from the composting of olive, elderberry, and grape agro-food waste. The experiment was carried out using reactors receiving straw as control and three treatments receiving mixtures of straw and olive, elderberry, or grape wastes. The gas emissions were measured for 150 days, and the composition of the mixtures and composts was determined. The results showed NH3 and CH4 emissions were reduced by 48% and 29% by the Olive and Elderberry treatments, while only NH3 loss was reduced by 24% by the Grape treatment. Nitrous oxide, CO2, and GWP emissions were reduced by 46%, 32%, and 34% by the Olive treatment, while these losses were not reduced by the Elderberry or Grape treatments. It can be concluded olive waste can effectively reduce NH3 and GWP, while elderberry and grape wastes are also effective in reducing NH3, but not GWP. Thus, the addition of agro-food waste appears to be a promising mitigation strategy to reduce gaseous losses from the composting process. [ABSTRACT FROM AUTHOR]

Over the last several years, the models for organic waste management have changed to implement circular economy in the productive cycle. In this context, new scenarios have emerged, where the management of different organic waste streams by composting is conducted with decentralized models that manage organic wastes in a more local way. However, in these new models, the standardization of the process control and of the end-product characteristics is necessary to guarantee the quality and agronomic value of the compost obtained, avoiding potential risks for human health and the environment. Thus, the aim of this work was to study two different scenarios of community composting of the organic fraction of municipal solid waste separately collected in order to guarantee the effectiveness and reproducibility of the composting processes and the quality of the composts obtained. For this, the development of the process and the characteristics of the composts at agronomic, hygienic–sanitary and environmental levels were assessed in real conditions and during three cycles of the process. The results obtained show high similarity among the different composting cycles, indicating an important degree of reproducibility among the processes. In addition, the composts obtained showed a good sanitary quality, absence of phytotoxicity and low contents of potentially toxic elements, which guarantee their use in agriculture without posing any risk to human health and to the environment. [ABSTRACT FROM AUTHOR]

The liquid waste (LW) discharged during bioethanol production needs treatment. In this study, LW was applied to corn, and its effects on corn growth, yield, and nitrogen (N) content, as well as on soil chemical properties, were evaluated. Five treatments were applied during corn cultivation: no fertilizer (NF), chemical fertilizer (CF), LW at a standard application rate (LW1.0), LW at 1.7 times the rate of LW1.0 (LW1.7), and split application of LW1.7 (S-LW1.7) in six replications. The amount of N applied was 30 kg 10a−1 for CF and LW1.0, and 51 kg 10a−1 for LW1.7 and S-LW1.7. N was applied separately three times in CF, LW1.0, and LW1.7 and six times in S-LW1.7. A higher corn yield, corn ear weight, and number of leaves was observed in LW treatments than in CF. N content of the corn plant top was higher in S-LW1.7 than in LW1.7; N availability was 56.9% and 40.5% higher, respectively, indicating that split application improved N availability. Soil total N content increased significantly in LW treatments, and soil total carbon content tended to increase in S-LW1.7. Therefore, application of LW could increase corn yield and soil fertility, and its effect could be enhanced by split application. [ABSTRACT FROM AUTHOR]

Growing awareness of the environmental impact of intensive agriculture has prompted a quest for more sustainable approaches. The most promising alternatives include the application of organic waste products (OWPs), as well as biofertilizers containing local beneficial microorganisms (BMs) on cultivated soils. This study was designed to assess the effects of BMs on carbon and nitrogen mineralization of OWPs. A 28-day laboratory incubation experiment was conducted at 28 °C with a soil, three OWPs (poultry litter (PL), cow dung (CD), and sewage sludge (SS)), and three BMs (groundnut + millet from Saint-Louis (LGM), groundnut from the southern groundnut basin (BG), and rice from the southern groundnut basin (BR) in Senegal), alone and combined. The results showed that the C mineralization from OWP + BM + soil mixtures exceeded (range 13–41%) those measured for OWP + soil. The BM input induced an increase or reduction in OWP nitrogen mineralization, depending on the type of BM and OWP. However, the net mineral nitrogen (Nmin) obtained with the PL-LGM and SS-BG combinations was 13.6- and 1.7-fold higher than with PL and SS, respectively, at 28 days. The addition of BM seemed to lead to a decrease in the C: N ratio, an improvement in the availability of nitrogen, and an increase in microbial activity in the OWP + BM + soil mixture. Our results generated new information on the variation patterns of OWP carbon and nitrogen in OWP-BM-soil systems. This novel insight will be developed to guide the most appropriate choice of OWP-BM mixtures for improved fertilization in sustainable production systems. [ABSTRACT FROM AUTHOR]

Composting is an interesting option to recycle big quantities of organic waste because it helps to mitigate different environmental problems. Complementary characteristics of rice straw (RS) and sewage sludge (SS) create a suitable mixture to be used in a composting process. This work studies industrial-scale RS and SS composting to assess both its viability and optimization. Windrow composting was conducted during two seasons. The complete characterisation (moisture, pH, electrical conductivity, total, oxidisable and water-soluble organic carbon, humic substances, organic and mineral nitrogen, macronutrients, micronutrients, heavy metals) of starting materials, samples taken periodically and final composts were carried out. During the first season, an RS:SS ratio of 1:8 (w:w fresh weight) was used, which led to a process with adequate temperatures for biodegradation, but not for ensuring materials' sanitation. During the second season, the RS:SS ratio was increased (1:6) to enhance the energy process and, thus, temperatures. Although this increase took place, degradation slowed down as oxidisable organic carbon and water-soluble organic carbon indicated. During both seasons, final composts presented adequate pH, high N-richness, and interesting macro- and micronutrient values. Notwithstanding, they also presented certain salinity and high ammonium contents, which must be considered for their field application. The obtained composts have interesting agronomic characteristics, which suggest their potential as an alternative to conventional fertilisers. [ABSTRACT FROM AUTHOR]

Composting is described as a sustainable alternative to organic waste reuse from the agricultural and household sectors. The organic matter degradation and stabilization product presents great variability due to the waste composition used. Thus, the use of techniques that allow the monitoring of the decomposition process is necessary to determine the quality of the final product. Therefore, this review critically analyzes and updates the chemical spectroscopy methods described for the evaluation of the organic matter transformation in the composting process to optimize and generate amendments for agricultural use. This review examines spectroscopic techniques such as ultraviolet-visible (UV-Vis), infrared (IR), fluorescence, and 13C NMR reported for the evolution and maturation of carbonate structures in composting. In addition, they are used in the study of indicators for monitoring the degradation of complex structures, such as sugars and proteins, for the formation of precursors that are responsible for the formation of highly stabilized substances such as humic and fulvic compounds. Finally, these parameters may be used to elucidate organic matter degradation and its stabilization process, establish patterns that characterize each stage of composting along with its physicochemical characteristics, and monitor potential phytotoxicity levels. [ABSTRACT FROM AUTHOR]

The raising of container seedlings with light substrates has become an important method of seedling raising, without delaying the seedling period. In order to reduce reliance on non-renewable peat and to promote the reuse of organic waste, this study compared the growth of sour jujube seedlings in different substrate formulations (i.e., different proportions of vermicompost instead of peat), using a semi-subterranean placement of root control bags, and explored the application of vermicompost in the raising of sour jujube seedlings. The results showed that there were significant differences in the growth and the physiological and photosynthetic characteristics of sour jujube seedlings treated with different substrates, among which substrates A2 (peat: vermicompost: vermiculite: garden soil = 0.5:0.5:1:1) and A3 (peat: vermiculite: garden soil = 1:2:1) were suitable for sour jujube seedling raising. The seedling height, the seedling ground diameter, the number of secondary branches, the length of the longest secondary branch, the total fresh weight, the aboveground fresh weight, the total root length, the root projection area, and the root surface area were all significantly greater than those of jujube seedlings grown on other substrates. Especially in A3, vermicompost can replace peat as the nursery substrate for sour jujube seedlings, removing dependence on non-renewable peat resources, reducing costs, and providing more prospects for application. The suitable substrate conditions for sour jujube seedlings were as follows: soil porosity 44.0–54.0%, electric conductivity (EC) value 0.2 mS/cm, organic matter 40.39~54.05 g·kg−1, total nitrogen and total phosphorus of 1.67~1.91 g·kg−1 and 0.95~1.20 g·kg−1, respectively, alkali-hydrolyzed nitrogen 139.75~154.69 mg·kg−1, and available phosphorus 137~224 mg·kg−1. [ABSTRACT FROM AUTHOR]

The agricultural valorization of organic waste, including digestate from anaerobic digestion, can be a good tool to remedy the problem of soil depletion by intensive crops. This study was conducted to evaluate the effect of digestate application on the chemical characteristics of the soil, including N, P, and K content, pH, and electrical conductivity, as well as the agronomic performance of forage corn (Zea mays L.). Digestate was applied and incorporated into the soil at different rates (0; 0+ recommended NPK rates; 15, 30, and 60 t dry weight (DW) ha−1). Digestate application at increasing doses improved soil chemical characteristics at harvest, and the application of 15, 30, and 60 t DW ha−1 significantly decreased soil pH by 0.15, 0.23, and 0.39 units, respectively. For electrical conductivity, the average values recorded are 196, 212, and 255 uS m−1, respectively, to 15, 30, and 60 t DW ha−1 doses. A significant organic matter enrichment of the topsoil layer was observed only for treatments receiving 30 and 60 t DW ha−1. Similarly, our results showed that the N, P, and K contents increased significantly with digestate application at both rates compared to the positive control. Morphological characteristics of the corn plants (height, leaf number, and collar diameter) and ecophysiology (stomatal conductance and chlorophyll) increased in a global manner compared to the negative control. Indeed, the obtained results showed that this improvement was not proportional to the applied doses for all analyzed parameters. However, there was no significant difference between the obtained values in amended plants with 15 t DW ha−1 and those in the positive control (recommended dose in NPK). In comparison to this previous one, height, leaf number, and collar diameter increased by 15%, 13%, and 20%, respectively, with a 30 t DW ha−1 dose and by 34%, 20%, and 24% with a 60 t DW ha−1 dose. Concerning the relative chlorophyll content and stomatal conductance, the values recorded in the plants amended with 60 t DW ha−1 are 1.7 and 2.2 times higher compared with the positive control. The fresh biomass, dry biomass, and root length parameters increased proportionally to the applied dose. [ABSTRACT FROM AUTHOR]

Although sugarcane yield is directly influenced by the availability of nitrogen (N), the efficiency of mineral N (MN) fertilization is considered to be low due to nitrate leaching and ammonia volatilization. Thus, the search for alternative sources of N that are cheaper and more consistent with sustainable farming practices has been stimulated. As chicken litter is an organic waste with the potential to supply N to major crops, we tested the hypothesis that the use of this litter as a source of organic N (ON) is as efficient as the application of MN (ammonium nitrate) in promoting the growth, nutrition, and yield of sugarcane plants grown during both plant cane and ratoon cane seasons. Experiments were conducted in a 5 × 5 × 2 subdivided plot scheme in the growing area of the Denusa Mill, Destilaria Nova União S/A, located in the midwest region of Brazil, with treatments consisting of five doses each of MN (0, 40, 80, 120, and 160 kg ha−1) and ON (0, 2, 4, 6, and 8 T ha−1), evaluated in two crop seasons (plant cane-2019/2020 and ratoon cane-2020/2021). The application of different doses of MN or ON influenced the height and number of tillers of sugar cane plants, and the application of ON, supplied by chicken litter, to this crop was as efficient as that of MN in promoting plant growth. MN and ON also increased the leaf content of N, P, and K; moreover, the absence of one source of nitrogen was compensated by the other. ON application (up to 4.8 T ha−1) also increased sugarcane yield in addition to promoting growth. Furthermore, this study highlighted the superior quality of the regrowth observed in the IACSP95-5094 cultivar, which manifested in increased tillering and stem diameter, resulting in consistently higher yields in the ratoon crop. [ABSTRACT FROM AUTHOR]

Biogas production from manure and other organic matter, or combinations thereof, is part of the circular economy, and the use of the digestate from biogas production for plant nutrition and thus for soil fertility restoration and organic carbon (C) sequestration completes the circular economy cycle. The use of digestate from biogas production in agriculture is one of the sustainable ways to manage manure or organic waste, an alternative to conventional chemical fertilizers, and a means to achieve the objectives of the European Green Deal. To this end, two two-factor pot experiments were carried out in 2019–2020. Factor A—1. Control (without fertilization), 2. Liquid cow manure 170 kg ha−1 N (N170), 3. Digested manure 170 kg ha−1 N (N170), 4. Digested manure 140 kg ha−1 N (N140), 5. Digested manure 110 kg ha−1 N (N110); Factor B—1. Plants not cultivated, 2. Plants cultivated. The experiments determined the effect of digestate on the changes in soil nitrate (NO3-N), ammonium (NH4-N) and mineral (NO3-N + NH4-N) nitrogen, and available phosphorus (P2O5) and potassium (K2O) in the soil without plants as well as with plants cultivated and evaluated the risk of migration of macronutrients into deeper soil layers. The results showed that the application of the highest allowed rates under the Nitrates Directive (N170) and N140 digestate is accompanied by the addition of high levels of ammonium (NH4-N) nitrogen, which alters the balance of ammonium (NH4-N) and nitrate (NO3-N) nitrogen in the soil, and the extent of their migration to the deeper layers. These results suggest that the application of digestate to agricultural land enhances the migration of nitrogen and, in phosphorus-rich soils, of phosphorus (PO4-P) compounds to deeper layers (>25 cm). In order to achieve environmental objectives, digestate rates should be based on the agrochemical properties of the soil and the needs of the plants and should not exceed 65% of the nitrogen needed by the plants from mineral fertilizers. [ABSTRACT FROM AUTHOR]

Prodigiosin is a red pigment produced by various microbial strains, of these, Serratia marcescens has been recorded as the major PG-producing strain. This microbial pigment has attracted much attention because it possesses potential applications in various fields. Thus, this active metabolite has been increasingly studied for bioproduction and investigated for its novel applications. Recently, several prodigiosin-related reviews were reported. These studies covered some aspects of the general physicochemical properties, pathway synthesis, production, and applications of prodigiosin in medicine. However, only a few works discussed the eco-friendly production of prodigiosin from organic wastes. Remarkably, the scaling-up of prodigiosin production and its potential applications in agriculture have rarely been reviewed or discussed. This review extensively presents and discusses the green biosynthesis, enhancement, and scaling-up of prodigiosin production from a wide range of organic byproducts/wastes using different methods of fermentation. Notably, this paper highlights the novel and promising applications of prodigiosin in agriculture via in vitro tests, greenhouse tests, and field studies. The action mechanisms related to some potential bioactivities and the toxicology studies of prodigiosin are also discussed. This review thus supplies scientific data for further research and the application of prodigiosin in the future. [ABSTRACT FROM AUTHOR]

Coffee waste is an organic material that can potentially be used in agricultural systems as an organic amendment. This study investigated the effects of the application of three concentrations of coffee waste (1%, 2%, and 4% w/v), used as an organic amendment, on soil free-living nematode communities, and in two different soil types (clay and sandy loam). Coffee waste incorporation did not appear to be toxic to the soil's free-living nematodes; on the contrary, it favored the nematode populations; this increase was greater in the sandy loam soil type. Our results show that the abundance of the cp-1 bacteria-feeding nematodes can be used as an indicator of the soil's enrichment or depletion phase. Panagrolaimus was the most promising genus to describe quality differentiations that occur in the soil system. Three months after coffee waste application, Panagrolaimus was found to be dominant in all coffee waste applications, indicating that the soil was in a phase of enrichment. Six months after the application, nematode community structure indices (enrichment and structure) showed that coffee waste was decomposed in the 1 and 2% treatments and that these systems were in a stage of nutrient depletion. In terms of agricultural practices, when a coffee waste dose is lesser than 4%, a second application is recommended before 6 months to avoid soil degradation. [ABSTRACT FROM AUTHOR]

Among various organic wastes, shrimp shell powder (SSP) was the most suitable carbon/nitrogen source for producing antinematode compounds (ANCs) via Bacillus veleznesis RB.EK7 fermentation. The fermentation process for the enhancement of antinematode activity was investigated. B. veleznesis RB.EK7 produced the highest antinematode activity in the medium containing 0.8% SSP with an initial pH of 6.5–7.0, and fermentation was performed at 35–37 °C with a saking speed of 150 rpm for 72 h. Targeting ANCs were purified from the fermented culture broth and identified as thymine (1) and hexahydropyrrolo [1,2-a]pyrazine-1,4-dione (2) based on nuclear magnetic resonance (NMR) and mass spectra analysis and were compared to those of the reported compounds. Notably, for the first time, these compounds were found as novel ANCs. Thymine (1) demonstrated a potential nematicidal effect with near 100% mortality of second-stage juvenile (J2) nematodes and anti-egg hatching effects of 70.1%, while hexahydropyrrolo [1,2-a]pyrazine-1,4-dione showed moderate antinematode activities with 64.2% mortality of J2 nematodes and anti-egg hatching effects of 57.9%. The docking study coupled with experimental enzyme inhibition results indicated that the potent nematicidal effect of these compounds may be possibly due to the inhibition of the targeting enzyme acetylcholinesterase. The data of this study suggest that SSP can be potentially reused for the eco-friendly production of ANCs for the management of black pepper nematodes. [ABSTRACT FROM AUTHOR]

The increasing mass of organic waste as well as the assumptions of a circular economy enforce the rational management of this type of waste. One method of recycling is composting, which makes it possible to use waste efficiently as an organic fertilizer. This paper presents the results of a comparative study of six different composts in terms of their agricultural quality. The aim of this study was to evaluate the bioavailable amounts of metals using single extractions with DTPA solution and to characterize various humic compounds. Particular attention was paid to the amounts of labile carbon (LC), hot water-extractable carbon (HWC), and the quantity and quality of humus substances (HS). Regardless of compost types, they were characterized by a small share of easily decomposable compounds such as fulvic acids (FAs), LC, and HWC, which may indicate the low susceptibility of compost humic substances to microbiological degradation in soil. In general, the bioavailable metal amounts found in the analyzed composts were low; therefore, the tested composts applied to the soil can be considered safe for the environment. [ABSTRACT FROM AUTHOR]

The continued and extensive use of synthetic herbicides to control weeds to maximize crop yield is no longer sustainable, as it results in negative impacts on the environment and human health. Innovative sustainable and resilient food production systems should preserve resources and environmental health by incorporating alternative natural herbicides, recycling waste, and favoring a circular economy. The present work assesses the value of different organic waste (Urtica dioica residues, Vicia faba pods, spent coffee grounds, and corn cobs) as bioherbicides and fertilizers in different seasons through pot and field two-year sequential experiments. Pot assays revealed that V. faba pods, spent coffee grounds, and corn cob waste showed the best inhibitory effect, which were subsequently evaluated in the Spring–Summer and Autumn crops. In the field, spent coffee grounds reduced the biomass of total naturally-emerged weeds and stimulated crop growth under scarce rainfall and warm days. However, its effect varied under different environmental conditions. Spent coffee grounds can partially control weeds in the field, which valorizes them as a bioherbicide and boosts sustainable agriculture. [ABSTRACT FROM AUTHOR]

Olive manufacturing generates the most polluting wastewater. Olive mill wastewater (OMW) contains a large amount of organic and inorganic fractions. Olive-oil-producing countries have investigated several treatments and valorization processes for better management of this waste. The Tunisian government adopted OMW spreading on soil to manage the waste and improve the organic matter in the soil of olive groves. The examination of soil after OMW spreading was set up to assess the physicochemical changes and better comprehend the soil's responses. An incubation of two types of artificial soil treated with 40 and 80 m3·ha−1 of OMW led to increased organic matter, phosphorus, nitrogen and potassium contents. The adsorption of the phenolic compounds in soil was dependent on the clay type and was shown by the behavior of the soil composed of bentonite clay. The germination index of tomato and alfalfa seeds recorded a positive test with OMW applied on soil, and it was in relation to the species utilized. This practice seems to be a solution for the management of OMW because it limits the use of chemical fertilizers and might be a convenient source of carbon in organic farming. [ABSTRACT FROM AUTHOR]

Agricultural waste is a type of solid waste that needs to be managed properly. Organic waste can be recycled to produce bokashi fertilizer, which can be used to improve soil health, increase crop production, and sanitize the environment. However, it may contain heavy metals that could be toxic to plants and can pollute the environment if not properly decomposed. This study was designed to evaluate the fertilizer quality of six different bokashi fertilizer ratios (bfrs) over seven- and thirty-day maturation periods. The raw materials used include horse bedding waste (HBW), cow dung (CD), and paddy husk charcoal (PHC) in different ratios, treated with an effective microorganisms (EM4) solution. All the nutrients studied (N, P, K, Mg, and Ca) were significantly affected by the bokashi fertilizer ratios (bfrs). The best bokashi fertilizer ratio was bokashi fertilizer ratio-6 (bfr6), but it was statistically similar to bokashi fertilizer ratio-5 (bfr5). Its N, P, K, Mg, and Ca contents were higher than the control (bfr1) by 133.9%, 225.5%, 196.4%, 105.0%, and 84.7%, respectively. Similarly, all these nutrients were significantly affected by time. N, P, K, and Mg increased by 21.2, 33.0%, 16.4%, and 28.8%, respectively, after 30 days of maturation, with a decrease in Ca only 2.4%, which was not significant A germination index (GI) of 90.1% was obtained using cabbage seeds. The heavy metals result and germination bioassay confirmed the safety and maturity of the bokashi fertilizer. In conclusion, the results revealed that good-quality bokashi fertilizer can be produced within 30 days. Bfrr5 and bfr6 are equally good candidates for producing good-quality bokashi fertilizer for effective crop growth. [ABSTRACT FROM AUTHOR]

Digestate is a residue of the anaerobic decomposition of organic waste for biogas extraction, but it can be reused as a source of nutrients. To examine the effect of digestate in kohlrabi production, field experiments were conducted during three seasons in two calendar years. The fertilization treatments included the application of solid digestate (two rates—DS1 and DS2), liquid digestate (two rates—DL1 and DL2), solid manure (two rates—MS1 and MS2), and mineral fertilizer (NPK) and were compared with a plot without fertilization (Ø). The results showed a significant increase in the yield with the use of solid and liquid digestate, as well as with NPK, in all growing seasons, while the microelement contents (Zn, Mn, and Cu) in the leaves were at optimum level. The applied treatments did not increase the plant-available nutrients (AL-P2O5, AL-K2O, Fe, Cu, and Zn) in the soil (except Mn). The application of DL2, MS1, and MS2 led to a higher Pb content in kohlrabi stems compared to the control, but the Pb content remained below the maximum permitted limit. Our research showed that digestate can be used as a valuable source of nutrients for kohlrabi production, with a low risk of soil and plant contamination by heavy metals. However, the control of soil, digestates, and manure quality is recommended. [ABSTRACT FROM AUTHOR]

Among various organic wastes, shrimp shell powder (SSP) was the most suitable carbon/nitrogen source for producing antinematode compounds (ANCs) via Bacillus veleznesis RB.EK7 fermentation. The fermentation process for the enhancement of antinematode activity was investigated. B. veleznesis RB.EK7 produced the highest antinematode activity in the medium containing 0.8% SSP with an initial pH of 6.5–7.0, and fermentation was performed at 35–37 °C with a saking speed of 150 rpm for 72 h. Targeting ANCs were purified from the fermented culture broth and identified as thymine (1) and hexahydropyrrolo [1,2-a]pyrazine-1,4-dione (2) based on nuclear magnetic resonance (NMR) and mass spectra analysis and were compared to those of the reported compounds. Notably, for the first time, these compounds were found as novel ANCs. Thymine (1) demonstrated a potential nematicidal effect with near 100% mortality of second-stage juvenile (J2) nematodes and anti-egg hatching effects of 70.1%, while hexahydropyrrolo [1,2-a]pyrazine-1,4-dione showed moderate antinematode activities with 64.2% mortality of J2 nematodes and anti-egg hatching effects of 57.9%. The docking study coupled with experimental enzyme inhibition results indicated that the potent nematicidal effect of these compounds may be possibly due to the inhibition of the targeting enzyme acetylcholinesterase. The data of this study suggest that SSP can be potentially reused for the eco-friendly production of ANCs for the management of black pepper nematodes.

Agriculture depends on fertilizers to provide nutrients for plants. Phosphorus (P) is one of these nutrients and is the second-most necessary for plant growth. Global production of P fertilizer is concentrated in Morocco, China and the United States. A large amounts of P resources are found in organic wastes that can be transformed through phosphate-solubilizing microorganisms during the composting process. In this study, we first determined the enzymatic activity of phosphatases and phytase from Pseudomonas aeruginosa ATC 15442. Second, we evaluated the mineralization of P in mature compost when inoculated with P. aeruginosa ATC 15442, phytases, a cocktail of phosphate-solubilizing enzymes and their combinations. Finally, we evaluated different concentrations of the cocktail trying to release more P in the compost. The results indicated that P. aeruginosa exuded alkaline phosphatases, acid phosphatase, neutral phosphatase and phytase. The enzymatic cocktail increased inorganic P (Pi) when added to the mature compost: this was able to release up to 95% more Pi in the compost compared to the amount of Pi released in the control compost. The current study demonstrated the importance of adding the cocktail to enhance Pi in mature compost; however, further studies are required to confirm the results and practical applications.

This study aimed to reuse groundnut oil processing by-product, groundnut cake (GNC) for the low-cost production of prodigiosin (PG) via microbial technology and to assess its novel potential application for the management of black pepper nematodes. Serratia marcescens TUN02 was found as the most active PG-producing strain. Various small-scale experiments conducted in flasks indicated that GNC at 1% may be used as the sole carbon/nitrogen source for cost-effective PG production by fermentation. Notably, no further commercial ingredients and salts are required to supplement into the culture medium of this fermentation. PG was further investigated for scale-up production in a 14-L bioreactor system and PG was produced at high yield (6886 mg/L) with large-scale volume (4 L) in a short cultivation time (10 h). PG was then purified and its nematicidal activity was evaluated and showed effective inhibition of juveniles and egg hatching of Meloidogyne incognita species, harmful on black pepper, with low IC50 values of 0.2 and 0.32 mg/mL, respectively. The simple medium containing 1% GNC is the first report of cost-effective biosynthesis of PG, as well as potential in vitro anti-egg hatching activity of PG. These results indicated the potential application of GNC for low-cost bioproduction of PG for promising and novel use in the management of black pepper nematodes.

Composting has become a preferable option to treat organic wastes to obtain a final stable sanitized product that can be used as an organic amendment. From home composting to big municipal waste treatment plants, composting is one of the few technologies that can be practically implemented at any scale. This review explores some of the essential issues in the field of composting/compost research: on one hand, the main parameters related to composting performance are compiled, with especial emphasis on the maturity and stability of compost; on the other hand, the main rules of applying compost on crops and other applications are explored in detail, including all the effects that compost can have on agricultural land. Especial attention is paid to aspects such as the improvement of the fertility of soils once compost is applied, the suppressor effect of compost and some negative experiences of massive compost application.

Composting is an important technology used to treat and convert organic waste into value-added products. Recently, several studies have been done to investigate the effects of microbial supplementation on the composting of agro-industrial waste. According to these studies, microbial inoculation is considered to be one of the suitable methods for enhancing the biotransformation of organic materials during the composting process. This review provides up-to-date research findings on microbial inoculation strategies and their role and functions in enhancing the composting process and the improvement of compost quality. Based on this review, the addition of microorganisms could enhance the composting process such as accelerating the organic matter degradation, mineralization and microbial enzymes activities, and the quality of the end-products such as high germination index. It is important to notice in this strategy that sludge's microbial consortium is feasible to enhance the composting process in pilot-scale and industrial-scale productions. Besides, it also reduces the cost of compost production. The findings of this review show the various positive impact of microbial inoculation on agro-industrial waste composting which in turn might be useful as a reference for selecting a suitable inoculum based on the type of waste materials. [ABSTRACT FROM AUTHOR]

This study aimed to reuse groundnut oil processing by-product, groundnut cake (GNC) for the low-cost production of prodigiosin (PG) via microbial technology and to assess its novel potential application for the management of black pepper nematodes. Serratia marcescens TUN02 was found as the most active PG-producing strain. Various small-scale experiments conducted in flasks indicated that GNC at 1% may be used as the sole carbon/nitrogen source for cost-effective PG production by fermentation. Notably, no further commercial ingredients and salts are required to supplement into the culture medium of this fermentation. PG was further investigated for scale-up production in a 14-L bioreactor system and PG was produced at high yield (6886 mg/L) with large-scale volume (4 L) in a short cultivation time (10 h). PG was then purified and its nematicidal activity was evaluated and showed effective inhibition of juveniles and egg hatching of Meloidogyne incognita species, harmful on black pepper, with low IC50 values of 0.2 and 0.32 mg/mL, respectively. The simple medium containing 1% GNC is the first report of cost-effective biosynthesis of PG, as well as potential in vitro anti-egg hatching activity of PG. These results indicated the potential application of GNC for low-cost bioproduction of PG for promising and novel use in the management of black pepper nematodes. [ABSTRACT FROM AUTHOR]

Controlling organic and mineral fertilisation is a major concern in tropical environments. An experiment was conducted on an arenosol in the Dakar region, the main market gardening area of Senegal, to evaluate treatments commonly used by farmers. Seven treatments were repeated three times: A mineral fertilisation (MF) treatment based on N-P2O5-K2O (10-10-20), and three organic treatments at two doses (dried sewage sludge (SS), poultry litter (PL) and a digestate from an anaerobic digestion (AD) of cow manures). Each of the organic treatments were supplemented with a normal dose (1) and a double dose (2) of mineral N and K fertiliser. A lettuce, carrot and tomato rotation was grown in four campaigns (2016–2020) on all of the plots. Yields of all three crops in all of the organic treatments were statistically similar (p > 0.05) to the MF in all four campaigns, except for the yield of the lettuce crop under treatment PL-2 in campaigns 2 and 3. The tomato yields were statistically similar under all of the organic treatments in all four campaigns. In contrast, the yields of the lettuce and carrot crops differed statistically from each other and under the different organic treatments in all four campaigns. The yields of all three crops differed in the campaigns with the fertilisation treatment. In each campaign, the yields of each crop were not correlated with the total amounts of N, P and K applied. These differences or similarities in yields are explained by the nature of the organic waste products, the accumulation of nutrients after several applications, the type of crop and interannual differences in temperature. [ABSTRACT FROM AUTHOR]

Agriculture depends on fertilizers to provide nutrients for plants. Phosphorus (P) is one of these nutrients and is the second-most necessary for plant growth. Global production of P fertilizer is concentrated in Morocco, China and the United States. A large amounts of P resources are found in organic wastes that can be transformed through phosphate-solubilizing microorganisms during the composting process. In this study, we first determined the enzymatic activity of phosphatases and phytase from Pseudomonas aeruginosa ATC 15442. Second, we evaluated the mineralization of P in mature compost when inoculated with P. aeruginosa ATC 15442, phytases, a cocktail of phosphate-solubilizing enzymes and their combinations. Finally, we evaluated different concentrations of the cocktail trying to release more P in the compost. The results indicated that P. aeruginosa exuded alkaline phosphatases, acid phosphatase, neutral phosphatase and phytase. The enzymatic cocktail increased inorganic P (Pi) when added to the mature compost: this was able to release up to 95% more Pi in the compost compared to the amount of Pi released in the control compost. The current study demonstrated the importance of adding the cocktail to enhance Pi in mature compost; however, further studies are required to confirm the results and practical applications. [ABSTRACT FROM AUTHOR]

Organic waste and the compost and vermicompost derived from it may have different agronomic values, but little work is available on this aspect of sewage sludge. A 75-day pot experiment with perennial ryegrass (Lolium perenne) as the test plant aimed to investigate the fertiliser value and organic matter replenishment capacity of digested sewage sludge (DS) and the compost (COM) and vermicompost (VC) made from it, applied in 1% and 3% doses on acidic sand and calcareous loam. The NPK content and availability, changes in organic carbon content and plant biomass, and the efficiency of the amendments as nitrogen fertilisers were investigated. The final average residual carbon content for DS, COM, and VC was 35 ± 34, 85 ± 46, and 55 ± 46%, respectively. The organic carbon mineralisation rate depended on the soil type. The additives induced significant N mineralisation in both soils: the average increment in mineral N content was 1.7 times the total added N on acidic sand and 4.2 times it on calcareous loam for the 1% dose. The agronomic efficiency of COM and VC as fertilisers was lower than that of DS. In the short term, DS proved to be the best fertiliser, while COM was the best for organic matter replenishment. [ABSTRACT FROM AUTHOR]

The correct development of the composting process is essential to obtain a product of high value from organic wastes. Nowadays, some composting mixture parameters (i.e., air-filled porosity, moisture and the C/N ratio) are used to optimize the composting process, but their suitability is still debated because the literature reports contrasting results. This paper aimed to find other parameters that control the correct development of composting. The relationship between these and the compost quality was then verified. Twelve different composting mixtures were prepared using different organic wastes and bulking agents and were aerobically treated in a 300 L composter. The physico-chemical and chemical parameters of initial mixtures were analyzed, with particular regard to the total and water-extractable forms of organic C and N and their ratios and correlated with the temperature measured during composting. A positive correlation between temperature parameters during the active phase and soluble forms of N in the initial mixtures was found. A high total organic C to soluble N ratio in the composting mixtures was correlated with the low quality of the compost produced. Based on the results, a minimum content of WEN (water-extractable N) (0.4% w/w) or a TOC/WEN (total organic C/WEN) ratio in the range of 40–80 was recommended to ensure the correct development of the process and to produce compost of high quality. [ABSTRACT FROM AUTHOR]

Horticultural crops produce huge amounts of wastes due to the large difference between total and marketable yields, and plant residues. The biological stabilization and sanitization of these organic materials directly on-farm through a simple technique such as composting may be a feasible and sustainable management strategy. The objectives of this research were to (i) estimate the sustainability and the energy impact of the on-farm composting process; (ii) to evaluate the agronomic performance and sustainability of the compost application, compared to a commercial organic fertilizer; and (iii) to identify the management and environmental hotspots. To accomplish these aims, a composting process was set up and monitored using the organic wastes and residues produced in the experimental farm. The compost produced was compared to a commercial organic fertilizer in combination with the use of cover crops in the rotation, in a two-year pepper cultivation. All processes were assessed using an energy analysis and a carbon stocks and emissions evaluation. Our findings point out that the composting process on-farm was environmentally sustainable in terms of energy consumption and carbon emissions and produced a good quality fertilizer. The use of this compost determined the best agronomic performance, especially when it was combined with other agro-ecological techniques. The yield values were slightly higher and statistically comparable with the commercial fertilizer ones. Moreover, the treatments that included the compost were most energy efficient and showed the best compromise between C emissions and C stocks. [ABSTRACT FROM AUTHOR]

Industrialization and urbanization have led to an increased accumulation of waste materials that are transformed into a nutrient-rich and high-quality product called vermicompost by the vermicomposting process. Vermicomposting is an ecofriendly and economically favorable biotechnological process that involves the interaction of earthworms and microorganisms. Due to the importance of this process and its great potential in dealing with the consequences of waste accumulation, this review aims to provide key insights as well as highlight knowledge gaps. It is emphasized that there is a great challenge in understanding and clarifying the mechanisms involved in the vermicomposting process. The optimization of the factors affecting the possible application of vermicompost is crucial for obtaining the final product. Information on the composition of bacterial communities, amount of vermicompost, effect on heavy metal content, plant pathogens, diseases and organic waste selection is here recognized as currently the most important issues to be addressed. By answering these knowledge gaps, it is possible to enable wider utilization of vermicompost products. [ABSTRACT FROM AUTHOR]

Livestock odors are unavoidable problems in modern industrial society. We foresaw a role for fermented organic wastes in controlling odorous gases. In this study, we applied fermented coffee grounds to the floor area of a dairy cow barn and assessed alterations in odor compounds and a microbial shift over a period of three weeks. The treatment dramatically reduced ten odor compounds (more than 50%), highlighting the utility of fermented coffee grounds as an excellent product to reduce odors derived from cow manure. By the end of the treatment, the microbial consortium showed increases in rare families whose prevalence and abundance before the treatment had been low. Network analysis manifested 23 bacterial families dominant in fermented coffee grounds, negatively connected with odorous compounds, indicating potential odor-reducing bacterial families. This study provides an insight into using bacteria at the community level as a treatment to solve an environmental issue; simultaneously, it suggests proper usage of organic wastes by recycling them as fermenters for beneficial bacteria. [ABSTRACT FROM AUTHOR]

The organic wastes of plant origin and, in particular, those coming from sources related to tourism activities, such as those generated from golf courses and touristic coasts, constitute an increasing concern due to the rise in their production and their unsuitable management. Thus, this work aimed to assess the use of different composting strategies to manage these specific green wastes, such as grass clippings and pruning waste from a golf course and marine plant debris, mainly from posidonia (Posidonia oceanica L.). To this end, two composting scenarios were established: the first only considered green wastes in the composition of the composting mixtures, and the second used sewage sludge as a co-composting agent. The temperature of the piles was monitored, and physicochemical and chemical parameters were also studied throughout the process. The results obtained showed that composting is a feasible method to manage and recycle this type of green waste, obtaining end products with suitable physicochemical and chemical characteristics. However, proportions of sea plant wastes in the composting mixture higher than 30% can compromise the fertilizing value of the final compost. Moreover, the use of an additional co-composting agent (sewage sludge) improved the characteristics of the end products obtained, provided that this co-composting agent had suitable initial characteristics. [ABSTRACT FROM AUTHOR]

In semi-arid vineyard agroecosystems, highly vulnerable in the context of climate change, the soil organic matter (OM) content is crucial to the improvement of soil fertility and grape productivity. The impact of OM, from compost and animal manure, on soil properties (e.g., pH, oxidisable organic C, organic N, NH4+-N and NO3−-N), grape yield and direct greenhouse gas (GHG) emission in vineyards was assessed. For this purpose, two wine grape varieties were chosen and managed differently: with a rain-fed non-trellising vineyard of Monastrell, a drip-irrigated trellising vineyard of Monastrell and a drip-irrigated trellising vineyard of Cabernet Sauvignon. The studied fertiliser treatments were without organic amendments (C), sheep/goat manure (SGM) and distillery organic waste compost (DC). The SGM and DC treatments were applied at a rate of 4600 kg ha−1 (fresh weight, FW) and 5000 kg ha−1 FW, respectively. The use of organic amendments improved soil fertility and grape yield, especially in the drip-irrigated trellising vineyards. Increased CO2 emissions were coincident with higher grape yields and manure application (maximum CO2 emissions = 1518 mg C-CO2 m−2 d−1). In contrast, N2O emissions, mainly produced through nitrification, were decreased in the plots showing higher grape production (minimum N2O emissions = −0.090 mg N2O-N m−2 d−1). In all plots, the CH4 fluxes were negative during most of the experiment (−1.073−0.403 mg CH4-C m−2 d−1), indicating that these ecosystems can represent a significant sink for atmospheric CH4. According to our results, the optimal vineyard management, considering soil properties, yield and GHG mitigation together, was the use of compost in a drip-irrigated trellising vineyard with the grape variety Monastrell. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effect of sewage sludge and composts produced from sewage sludge and municipal waste on the content of various forms of nitrogen in soil. The field experiment was carried out in 2004–2015. It included three crop rotations of the following plants: potato, spring barley, winter oilseed rape and winter wheat. The experiment consisted of the following treatments: control (without fertilization), NPK, manure (FYM), compost from municipal sewage sludge and straw (CSSS), composted sewage sludge (CSS), dried and granulated sewage sludge (DGSS), "Dano" compost produced from unsorted municipal waste (CUMW) and compost from municipal green waste (CMGW). Manure, composts and sewage sludge were applied once (10 t ha−1 of d.m.) or twice (5 t ha−1 of d.m.) in a crop rotation. It was significantly shown that the highest N-total content was in the soil fertilized with CUMW (compost produced from unsorted municipal waste). The soil fertilized with manure (FYM) contained the highest quantity of N-min. The prevalent pool of nitrogen (82.65–86.52%) consisted of N compounds not undergoing acid hydrolysis, and their smallest share was determined in the soil fertilized with NPK alone. [ABSTRACT FROM AUTHOR]

A three-year field study was conducted to evaluate the impact of two different agro-industrial byproducts on soil properties, provisioning services, olive quality and production in a traditional rainfed olive grove to assess suitable management options for recycling organic wastes and reduce the use of inorganic fertilizers. The organic amendments consisted of compost (AC), made from residues from the olive oil industry ("alperujo"), and biosolid compost (BC), constituted of wastewater sludge and green waste from parks and gardens. The compost addition enhanced carbon storage, available phosphorous and potassium content overtime, whereas no effect was detected on soil hydraulics, yield and olive trees growth, partly due to the high variability encountered among plots. Beneficial effects, especially carbon storage, were more evident during the fourth sampling, where carbon content increased by almost 40% for BC, suggesting that compost effects need to be evaluated in the long term. Strong seasonal changes of most of the physico-chemical parameters were detected, and therefore the effect of the compost could have been partly masked. Establishing a non-climatic variation scenario would be advisable to fully detect compost effects. Our results suggest that different agro-industrial byproducts could be potentially viable and valuable source of fertilization, favoring in this way a circular economy of zero waste. [ABSTRACT FROM AUTHOR]

A transformation towards sustainable food production requires improved circular nutrient management. Urban organic waste contains relevant nutrients and organic matter, yet only 4% of global urban nitrogen (N) and phosphorus (P) sources are presently recycled. One recycling approach is the composting of urban wastes for urban horticulture. We characterized compost from various urban waste fractions and assessed their fertilizer value in a pot trial with lettuce plants. Seven treatments were investigated: food waste vermicompost with coir and paperboard bedding material, thermophilic compost from green waste and human feces, two references with mineral fertilization and a sand control. The lettuce yield and total uptake of P, potassium (K), calcium (Ca), and magnesium (Mg) were highest in plants grown in coir-based vermicompost. The fecal compost led to the highest shoot P and K content, but the shoot uptake of Ca and Mg were lower than in the other treatments. All composts required additional N for lettuce growth. In conclusion, urban waste-derived vermicompost and fecal compost demonstrate a high delivery rate of plant-available Ca, Mg, P, and K. Research is needed on macronutrient availability and alternative N sources for the substitution of synthetic fertilization. These findings support the production of urban waste composts, furthering efforts in nutrient recycling. [ABSTRACT FROM AUTHOR]

Organic wastes applied as composted amendments may improve the quality of degraded soils and modify the fate of pesticides. This work has set out to study the dissipation kinetics of the herbicides chlorotoluron and flufenacet during their second-year application in field experimental plots with a sandy-loam agricultural soil without amendment (S) and amended with spent mushroom substrate (S + SMS) or green compost (S + GC). The SMS and GC were applied to the soil during the previous winter's wheat crop campaign (1 year before the second herbicide application) at rates of 140 and 85 t ha−1 (dry weight basis), respectively. The experiment involved randomized complete blocks with plots of 81 m2, including three replicates per soil treatment. Surface soils were sampled after herbicide application for 225 days, and herbicide residues in the soil samples were determined by HPLC-MS. The dissipation curves of both herbicides for the three soil treatments were better fitted to the first order multi-compartment (FOMC) kinetic model. The dissipation rates of the most hydrophobic herbicide, flufenacet, were slower than those for chlorotoluron in both unamended and amended soils. The half-life (DT50) values ranged between 20.7 to 41.1 days for chlorotoluron, and 42.9 to 75.6 days for flufenacet, and they followed the order S > S + SMS > S + GC. The DT50 values of chlorotoluron were close for S + SMS and S + GC, and the DT50 of flufenacet for S was similar to that for S + SMS. These DT50 values decreased up to four times with respect to those calculated after the first application indicating an accelerated dissipation of the herbicides after the second application especially in amended soil in comparison with unamended soil. The persistence of chlorotoluron and flufenacet in an agricultural soil was modified by the effect of the organic amendments, weather conditions, and possibly the repeated application of the compounds under real field conditions. [ABSTRACT FROM AUTHOR]

Dairy products are vital components of human food, however, they are rapidly spoiled due to their high content of organic matter which encourages the growth of decomposing microbes. The recycling of dairy wastes is an ideal solution to preserve the environment, as it is in line with the principles of sustainable agriculture. In this experiment, an organic fertilizer was extracted from dairy wastes and was used for the nutrition of wheat grown on sandy soils under two-year field studies. The application rate of the extracted organic fertilizer was 8 ton ha−1. Moreover, the same rates of N, P, and K were added from inorganic fertilizers. The extracted organic fertilizer significantly (p < 0.05) enhanced the wheat growth and increased chlorophyll by 11% and 16% in the first and second season, respectively, in comparison to the inorganic fertilization. The extracted organic fertilizer significantly minimized the soil pH from an initial value of 8.00 to 7.05. The tested organic fertilizer increased the uptake of N, P, and K by 55%, 49%, and 51% above the inorganic nutrition, respectively. The wheat straw and grain yield increased by 16% and 29% as a result of the addition of the organic fertilizer extracted from dairy wastes. The dairy wastes organic fertilizer caused a notable improvement in the soil quality. The extracted organic fertilizer was able to supply wheat with its nutrient requirements as it showed a remarkable superiority over the mineral fertilization. The disposal of expired dairy waste can be managed in a way that preserves the environment by converting it to organic fertilizers. Laboratory and field experiments have proven the efficiency of the extracted organic fertilizer in nutrition of wheat plants in sandy soils with low fertility. [ABSTRACT FROM AUTHOR]

Dairy cattle farming produces large amounts of wastewater and it causes environmental pollution and eutrophication of rivers, but the nutrients in the waste could be recycled. Here, an improved vermicomposting system was applied to dairy farm wastewater, and wastewater with a nitrogen content of 100 mg/L and 200mg/L tested with different combinations of organic substrates such as cow manure and rice straw in rural solid waste. Results showed that earthworms could continuously grow, wastewater (N 100mg/L) mixed with rice straw corresponding to the most significant gained weight for Eisenia fetida earthworms (2.38 to 9.12-fold), and the earthworms' weight was positively correlated with the C/N ratio, organic matter content, and pH. Compared to the initial state, the system significantly changed physicochemical parameters in nutrients, such as the percentages of total nitrogen, phosphorous, and potassium, which were found to increase in vermicomposting while organic matter content, C/N ratio, and cellulose declined as a function of the vermicomposting period, and the final vermicompost was better for the absorption of plants. These results suggest that continuous wastewater addition improved the effective transformation of organic waste to allow valorizing a broad range of organic residues, and avoid the risk of environmental pollution in dairy cattle farming. [ABSTRACT FROM AUTHOR]

Healthy soils are essential for progressive agronomic activities. Organic fertilization positively affects agro-ecosystems by stimulating plant growth, enhancing crop productivity and fruit quality and improving soil fertility. Soil health and food security are the key elements of Organic Agriculture 3.0. Landfilling and/or open-dumping of animal wastes produced from slaughtering cause environmental pollution by releasing toxic substances, leachate and greenhouse gases. Direct application of animal carcasses to agricultural fields can adversely affect soil microbiota. Effective waste management technologies such as thermal drying, composting, vermicomposting and anaerobic digestion transform animal wastes, making them suitable for soil application by supplying soil high in organic carbon and total nitrogen. Recent agronomic practices applied recycled animal wastes as organic fertilizer in crop production. However, plants may not survive at a high fertilization rate due to the presence of labile carbon fraction in animal wastes. Therefore, dose calculation and determination of fertilizer application frequency are crucial for agronomists. Long-term animal waste-derived organic supplementation promotes copiotrophic microbial abundance due to enhanced substrate affinity, provides micronutrients to soils and protects crops from soil-borne pathogens owing to formation of plant-beneficial microbial consortia. Animal waste-derived organically fertilized soils possess higher urease and acid phosphatase activities. Furthermore, waste to fertilizer conversion is a low-energy requiring process that promotes circular bio-economy. Thus, considering the promotion of soil fertility, microbial abundance, disease protection and economic considerations application of animal-waste-derived organic fertilizer should be the mainstay for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Repeated applications of organic waste products (OWP) are a source of trace elements (TE) inputs to agricultural topsoils. The present study aimed at (i) assessing the effects of repeated OWP inputs on the chemical properties of topsoils in two long-term field experiments (13 and 15 years; calcareous and non-calcareous soils), (ii) evaluating TE phytoavailability and their transfer to grain (winter wheat and maize) and (iii) identifying the underlying factors causing alterations of TE phytoavailability. In both field experiments, receiving compliant or slightly high doses of OWP in compliance with regulations, OWP and soil physicochemical properties and TE concentrations in soils and grains were determined. In situ phytoavailability of TE was assessed at two juvenile crop growth stages by analyzing TE concentrations in shoot plantlets. Depending on the OWP input amount, results showed that compared to the soil receiving no organic amendment, repeated OWP inputs significantly increased soil organic carbon content, pH, cation exchange capacity, total soil Cu, Mo and Zn concentration and the phytoavailability of Mo, while the phytoavailability of Cd, Mn, Ni and Tl was significantly reduced. No notable effect was observed for Cr, Cu, Hg, Pb and Zn phytoavailability. Statistical approaches suggested that due to the repeated OWP applications, increased soil organic carbon content and pH, were likely responsible for decreased TE phytoavailability (e.g., Cd). [ABSTRACT FROM AUTHOR]

Anaerobic digestion of organic wastes produces solid residues known as digestates, which have potential as a fertilizer and soil amendment. The majority of research on digestate focuses on their fertilizer value. However, there is a lack of information about additional effects they may have on plant growth, both positive and negative. Understanding the effects of digestate on plant growth is essential to optimizing their use in agriculture and helping close the loop of material and energy balances. This greenhouse study evaluated the effects of two different digestates, a food waste digestate (FWD) and a lignocellulosic biomass digestate (LBD); a liquid fertilizer; and various combinations of fertilizer and digestates on plant growth, nutrient uptake and nutrient use efficiency (NUE) of Brassica juncea (kai choy) plants. It also evaluated potential negative attributes of the digestates, including salinity and possible biohazards. Combinations of LBD and fertilizer performed as well or slightly better than the fertilizer control for most parameters, including aboveground biomass and root length. These same combinations had significantly higher nitrogen use efficiency than the fertilizer control. Inhibitory effects were observed in 100% LBD treatments, likely due to the high electrical conductivity of the media from digestate application. Based on this research, LBD could partially replace mineral fertilizers for kai choy at up to 50% of the target nitrogen rate and may lead to increased plant growth beyond mineral fertilizers. FWD could replace up to 100% of the target nitrogen application, without causing significant negative effects on plant growth. Increasing the use of digestates in agriculture will provide additional incentives for the anaerobic digestion process, as it produces two valuable products: biogas for energy and digestate for fertilizer. [ABSTRACT FROM AUTHOR]

Waste exogenous organic matter, including spent mushroom substrate (SMS) and chicken manure (CM), can be used as the basis of a soil-improving cropping system in sustainable agriculture. However, there is—as yet—a lack of information about important quality indicators such as the fungal community relative abundance, structure and biodiversity in soils treated with these additives. In this study, the responses of the soil fungal community composition and mycobiome diversity to SMS and CM application compared to the control soil were evaluated using a combination of the following molecular approaches: quantitative polymerase chain reactions, denaturing gradient gel electrophoresis, terminal restriction fragment length polymorphism, and next-generation sequencing. The most abundant phylum for both treatments was Ascomycota, followed by Basidiomycota. The application of SMS and CM increased the abundance of fungi, including Tremellomycetes and Pezizomycetes for the SMS additive, while the Mortierellomycetes, Pezizomycetes, and Leotiomycetes levels increased after CM addition. SMS and CM beneficially reduced the relative abundance of several operational taxonomic units (OTUs) which are potential crop pathogens. The results provide a novel insight into the fungal community associated with organic additives, which should be beneficial in the task of managing the soil mycobiome as well as crop protection and productivity. [ABSTRACT FROM AUTHOR]