Innovative Approaches in Agricultural Waste Management

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Farming Sustainability".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 9541

Special Issue Editors

Unit of Microbiology, Department of Biology and Geology, University of Almeria, 04120 Almeria, Spain
Interests: composting; bioremediation; biological control; lignin degradation; microbiome of composting; enzymes of composting; organic waste management
Unit of Microbiology, Department of Biology and Geology, University of Almeria, 04120 Almeria, Spain
Interests: composting; bioremediation; biological control; lignin degradation; microbiome of composting; enzymes of composting; organic waste management

Special Issue Information

Dear Colleagues,

Agricultural activity is certainly responsible for sustaining the population’s food supply. Parallel to the generation of the food and goods that society demands, agriculture produces a huge amount of biodegradable waste that poses an interesting present and future challenge. The use of effective methods for managing this organic waste is a powerful tool for promoting a truly sustainable future for agriculture.

The composition of the waste generated is as wide and diverse as that of agricultural crops. However, the recalcitrance of these residues is based on the lignocellulose polymer structure, which is more represented in nature. Whether using biodegradable processes or energy recovery methods, the conversion of these wastes into products of interest for the circular economy model is an increasingly present reality.

This Special Issue will focus on “Innovative Approaches in Agricultural Waste Management”. Research papers, reviews, and opinion articles covering all related topics, including circular economy, management alternatives such as composting, anaerobic treatment and energy recovery, improvement of current management processes, and potential use of agricultural waste in biorefineries and policy positions are welcome.

Dr. Juan Antonio López González
Dr. Macarena M. Jurado
Guest Editors

Manuscript Submission Information

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Keywords

  • agricultural waste management
  • composting
  • anaerobic treatment
  • circular economy
  • energy recovery
  • biological treatment
  • biorefinery

Published Papers (7 papers)

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Research

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19 pages, 1106 KiB  
Article
Residues from Medicinal and Aromatic Plants after Distillation Can Be Used in Replace Some Peat in the Growing Media for Viola × wittrockiana Production
by Antonios Chrysargyris and Nikolaos Tzortzakis
Agronomy 2024, 14(1), 187; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy14010187 - 15 Jan 2024
Viewed by 867
Abstract
Plant residues derived from the agro-industrial sector and their disposal are still unsolved issues despite the various research and applications. The current study assessed the possible peat substitution in growing media with solid residues derived from the distillation of Origanum dubium Boiss (OD) [...] Read more.
Plant residues derived from the agro-industrial sector and their disposal are still unsolved issues despite the various research and applications. The current study assessed the possible peat substitution in growing media with solid residues derived from the distillation of Origanum dubium Boiss (OD) and Sideritis cypria Post (SC) after essential oils production. Residues of OD and SC (0–5–10–20% v/v) and their mixture (OD + SC) were examined to partially substitute peat for the production of pansy (Viola × wittrockiana) plants. The presence of OD, SC, and OD + SC residues increased the pH, the electrical conductivity, the organic matter content, and the levels of minerals in the growing media mixtures compared to sole peat while decreasing the total porosity (up to 36.8%) and the available free air (up to 58.3%). The OD residues’ presence in the peat-based media revealed more detrimental effects than the SC, while the OD + SC mixture received intermediate effects. Low residue ratios (≤5% OD, ≤10% SC, ≤10% OD + SC) sustain plant growth and photosynthetic activity of plants, while higher ratios decrease plant growth, chlorophyll content and mineral accumulation due to inappropriate growing media properties, causing plant oxidative stress. This was verified using the increase in malondialdehyde (up to 4.5 times) and hydrogen peroxide (up to 2.1 times) content in plants and the activation of several non-enzymatic antioxidant processes, including total phenols, flavonoids, and antioxidant capacity of the plants. Therefore, OD, SC, and OD + SC at 5%, 10%, and 10%, respectively, can partially substitute peat, as they result in appropriate plant growth and development. However, the growing media’s properties must be improved to ensure adequate yields as well. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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18 pages, 1660 KiB  
Article
Study of Raw Material Pretreatment and the Microbiota Selection Effect on the Composting Process Efficiency
by Abdo Tannouri, Ziad Rizk, Marina Daccache, Chantal Ghanem, Valérie Azzi, Richard G. Maroun, Zeina Hobaika and Dominique Salameh
Agronomy 2023, 13(8), 2048; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy13082048 - 02 Aug 2023
Cited by 2 | Viewed by 1000
Abstract
Lignocellulosic is a carbon source biomass composed of cellulose, hemicelluloses, and lignin, which are strongly associated with each other. This fact makes them hardly degradable by produced microbial enzymes when introduced to compost piles. To address this problem, a primary single or combined [...] Read more.
Lignocellulosic is a carbon source biomass composed of cellulose, hemicelluloses, and lignin, which are strongly associated with each other. This fact makes them hardly degradable by produced microbial enzymes when introduced to compost piles. To address this problem, a primary single or combined pretreatment method of this biomass allows for the separation of these complex, interlinked fractions, allowing a better accessibility for microbial enzymes. However, the rugged lignin component, in addition to several produced by products from these pretreatments, inhibit the microbial activity. For this, the optimization of these treatments with other interfering parameters is the base for a successful composting process. In this work, nine compost piles were initiated, in which their lignocellulosic fraction was subjected to chemical and microbiological treatments alone or combined while preserving a control. The obtained results showed that the combined pre-treatment of the primary organic raw materials with 10% NaOH and adapted microbial inoculum at 2.5% was the best suited for compost piles in Mediterranean regions. This treatment ensured the quickening of the composting process by 15 days, while yielding a final compost of a higher quality in regard to its physic-chemical characteristics, especially its C:N and CC values. Furthermore, it ensured a higher sanitation through the elimination of different microbial pathogens from the final compost, by means of the secondary metabolites produced by the microbial adapted consortia. This ‘tailor-made’ process could be replicated for the treatment of other generated sources of organic raw materials within the Mediterranean region. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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21 pages, 4044 KiB  
Article
Effect of Upstream Bioactivation of Plant Residues to Accelerate the Composting Process and Improve Product Quality
by María R. Martínez-Gallardo, María J. Estrella-González, Francisca Suárez-Estrella, Juan A. López-González, Macarena M. Jurado, Ana J. Toribio and María J. López
Agronomy 2023, 13(6), 1638; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy13061638 - 19 Jun 2023
Cited by 2 | Viewed by 1030
Abstract
Composting is considered an efficient and environmentally friendly alternative for plant waste management, resulting in compost, a high value-added product. During the process, microorganisms play a crucial role as organic matter-degrading agents. However, the highly recalcitrant nature of the lignocellulose present in plant [...] Read more.
Composting is considered an efficient and environmentally friendly alternative for plant waste management, resulting in compost, a high value-added product. During the process, microorganisms play a crucial role as organic matter-degrading agents. However, the highly recalcitrant nature of the lignocellulose present in plant residues sets a challenge to the microorganisms involved in the process. Therefore, the objective of this study was to evaluate the effect of a lignocellulolytic microbial consortium, previously selected in composting processes, to promote and improve the biodegradability of plant residues. For this purpose, a laboratory-scale inoculation strategy was optimized by applying different strains and doses of Bacillus spp., as well as different incubation times. Subsequently, the impact of the application of the consortium on the waste material as a pretreatment of a real composting process was evaluated. Samples from both experiments were subjected to the evaluation of parameters related to the biodegradation of the lignocellulosic fraction, in addition to those related to the stability and maturity of a compost. The inoculum proved to be effective in promoting the bioactivation of the material, favoring a higher respirometric rate and biodegradability during laboratory-scale pretreatment. In this case, inoculation with B. safensis at high doses resulted in AT4 values higher than those observed for the rest of the treatments after ten days of incubation, while B. licheniformis inoculated at lower doses was able to maintain higher AT4 values after ten days, compared to those observed in the rest of the samples analyzed. Additionally, inoculation with both strains resulted in a continuous decrease in the percentage of hemicellulose that could be detected until the end of the incubation period (thirty days), reaching biodegradation rates close to 40%. On the other hand, although the inoculation did not significantly affect the basic conditioning parameters at the beginning of the composting process (organic matter, C/N ratio, and moisture), a change in the dynamics of the lignocellulosic fractions was observed during the process, as well as in the evolution of other stability and maturity parameters, in particular the AT4 index and the lignin/holocellulose ratio, revealing an acceleration of the bio-oxidative phase during the full-scale composting process. Therefore, the treatment of plant waste with lignocellulolytic microorganisms is proposed as an effective alternative to activate the biodegradability of organic waste at the beginning of a composting process, resulting in better-quality products. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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18 pages, 2552 KiB  
Article
Priming Effects of Maillard Reaction Precursors on Rice Straw Decomposition at Different Incubation Temperatures
by Nan Wang, Yuping Zeng, Miao Wang, Linjun Shen, Zhijiang Liu, Long He, Xin Zhao, Hongpeng Guo, Yue Liu and Shuai Wang
Agronomy 2023, 13(1), 230; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy13010230 - 12 Jan 2023
Viewed by 1158
Abstract
To verify the priming effects of Maillard reaction precursors on the microbial decomposition of rice straw at different incubation temperatures, the method of indoor incubation at a constant temperature was adopted. In the process, the addition of glucose, catechol or glycine solution alone [...] Read more.
To verify the priming effects of Maillard reaction precursors on the microbial decomposition of rice straw at different incubation temperatures, the method of indoor incubation at a constant temperature was adopted. In the process, the addition of glucose, catechol or glycine solution alone or in mixed solution was conducted at incubation temperatures of 10 °C, 15 °C and 28 °C, respectively. The C content of humic-extracted acid (CHLE), humification index (the ratio of C content of humic-like acid to fulvic-like acid, CHLA/CFLA), ∆logK value of humic-like acid (HLA), and C content of humin-like acid (CHLu) were dynamically analyzed at 0, 30, 60, and 90 d, respectively. At the same time, the differences in the atomic ratio and FTIR spectra before and after incubation were systematically analyzed. The results showed that (1) the additions of glucose alone and mixed precursors were both beneficial to increasing the CHLE content at three tested temperatures, especially at two low temperatures (10 °C and 15 °C), and glucose alone manifested the most significant improvement in CHLE. In contrast, following the addition of glycine alone, the CHLE content decreased by 2.4% at 15 °C and 4.6% at 28 °C after incubation. (2) Glucose as the sole precursor was more beneficial to improving the quality of the humic substance (HS) at 28 °C, but only enhanced the condensation degree of HLA molecules at 15 °C. Compared with the results at 15 °C and 28 °C, the HLA molecules had the lowest condensation degree at 10 °C, regardless of whether a single precursor or mixed Maillard precursors were used. (3) After incubation, the amounts of N compounds in the HLA molecules decreased to varying degrees, especially at 28 °C. The O-containing functional groups, such as carboxyl groups, from HLA molecules decreased following the addition of a single precursor, while the mixed precursors resulted in an increase in O-containing functional groups. Increasing the catechol content directly enriched the unsaturated bonds of HLA. With the decomposition of rice straw, regardless of how the precursors were added, the polysaccharide content decreased to different degrees. The decomposition of polysaccharides in HLA was more temperature-sensitive, and an increase in temperature might encourage more polysaccharide consumption. Under each temperature, the molecular structure of HLA was simplified initially and then gradually became complex. Finally, the addition of glucose alone at 15 °C was more favorable for the complexity of HLA molecules, while at 28 °C, it could only alleviate the degree of simplification of the HLA molecular structure to a certain extent. (4) At the three tested temperatures, compared with the CK control, either one precursor or a mixture of three precursors could more effectively promote the decomposition of CHLu. Under the conditions of 10 °C and 15 °C, the addition of mixed precursors was more beneficial to the decomposition of CHLu, causing the CHLu content to decrease by 37.9% and 44.7%, respectively, followed by the addition of glucose alone. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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11 pages, 744 KiB  
Article
Evaluation of Physicochemical On-Farm Quick Tests for Estimating Nutrient Concentrations in Pig Slurry and Development of an Application for Mobile Devices
by Max-Frederik Piepel, Klaus Dittert and Hans-Werner Olfs
Agronomy 2022, 12(11), 2809; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy12112809 - 10 Nov 2022
Cited by 4 | Viewed by 1063
Abstract
Farmers need to know the actual nutrient concentrations in organic manures in order to enable optimal crop nutrition and to avoid nutrient losses into the environment. Physicochemical quick tests offer a way to estimate nutrient concentrations on a farm but require statistical calculation [...] Read more.
Farmers need to know the actual nutrient concentrations in organic manures in order to enable optimal crop nutrition and to avoid nutrient losses into the environment. Physicochemical quick tests offer a way to estimate nutrient concentrations on a farm but require statistical calculation models to be applied by the farmer. A total of 391 pig slurries, were sampled from practical farms in northwest Germany and ammonium nitrogen (AN), total nitrogen (TN), total phosphorus (TP), total potassium (TK) concentrations, and dry matter were analysed in a laboratory. Furthermore, on-farm quick tests were used to determine electrical conductivity and specific density (SG) and the ammonium concentration with a Quantofix-N-Volumeter. Simple and multiple linear regression models for all lab analysed nutrients and on-farm determined parameters were calculated. The best regression models for all slurries were found for AN based on Quantofix-N-Volumeter (R2 = 0.92), TN based on Quantofix-N-Volumeter, and dry matter (R2 = 0.95), TP based on dry matter (R2 = 0.88), and TK based on Quantofix-N-Volumeter (R2 = 0.70). An application for mobile devices is being developed that will allow farmers to use these statistical models in a user-friendly way. Future regression models from other studies might be integrated into the app database so that farmers can calculate nutrient concentrations in pig slurries based on regionalised data. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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14 pages, 19067 KiB  
Article
Utilisation of Oil Palm’s Empty Fruit Bunch Spikelets for Oil-Spill Removal
by Nurul Aini Puasa, Siti Aqlima Ahmad, Nur Nadhirah Zakaria, Noor Azmi Shaharuddin, Khalilah Abdul Khalil, Alyza Azzura Azmi, Claudio Gomez-Fuentes, Faradina Merican, Azham Zulkharnain, Yih-Yih Kok and Chiew-Yen Wong
Agronomy 2022, 12(2), 535; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy12020535 - 21 Feb 2022
Cited by 3 | Viewed by 2451
Abstract
Agricultural sorbents have received attention for their effectiveness in oil removal. In Malaysia, oil palm’s empty fruit bunch (EFB) spikelets are an abundant agricultural waste that provides a non-toxic, renewable resource of cellulosic materials. In this study, the effectiveness of EFB spikelets to [...] Read more.
Agricultural sorbents have received attention for their effectiveness in oil removal. In Malaysia, oil palm’s empty fruit bunch (EFB) spikelets are an abundant agricultural waste that provides a non-toxic, renewable resource of cellulosic materials. In this study, the effectiveness of EFB spikelets to remove oil spills from seawater pollution in a filter system was investigated and the best optimisation approach for filtering conditions was determined. Experiments for oil spill clean-up were performed using a filter-based oil sorption system with a series of conditions such as temperature, time, packing density, and oil concentration to evaluate sorption capacity, oil and water absorbed efficiency. Fourier transform infrared spectroscopy (FTIR) was used to characterise the physicochemical properties of untreated and treated EFB fibres. Based on one-factor-at -a-time (OFAT) analysis conducted at 160 °C for 30 min on 0.1 g/cm3 of packing density containing 25% diesel, 8.667 mL of oil and 5 mL of water was absorbed. In response surface methodology (RSM), the three parameters of temperature, packing density and diesel concentration were observed as significant. From RSM fitting model analysis, the predicted value obtained for both oil and water absorbed were 8.805 and 5.213 mL, respectively. The experimental RSM values of 9 and 5 mL of oil and water absorbed were obtained. The result demonstrated the validity of the model as the experimental RSM values were close to the RSM model’s prediction. As compared to OFAT, the RSM method is more efficient in oil removal. This research contributes to a better knowledge of the usage of a natural sorbent as a method of diesel pollution remediation. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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Review

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24 pages, 1902 KiB  
Review
Phytotoxicity Removal Technologies for Agricultural Waste as a Growing Media Component: A Review
by Wenzhong Cui, Qi Bai, Juncheng Liu, Jing Chen, Zhiyong Qi and Wanlai Zhou
Agronomy 2024, 14(1), 40; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy14010040 - 22 Dec 2023
Viewed by 807
Abstract
In response to the challenge of resource recycling, this review investigates the removal of phytotoxicity from agricultural waste for its application as a growing media component. Agricultural waste typically exhibits high phytotoxicity due to the presence of substances such as phenols, organic acids, [...] Read more.
In response to the challenge of resource recycling, this review investigates the removal of phytotoxicity from agricultural waste for its application as a growing media component. Agricultural waste typically exhibits high phytotoxicity due to the presence of substances such as phenols, organic acids, ammonia, nitrogen, and heavy metals. These substances hinder seed germination and plant growth, posing a significant barrier to the use of agricultural waste as a growing media component. Thus, it is imperative to mitigate or eliminate phytotoxicity before effectively utilizing agricultural waste. This review rigorously analyzes an extensive array of recent studies, scrutinizing diverse technologies for the mitigation of phytotoxicity in agricultural wastes. The methods investigated include the four most common methods—composting, heat treatment, washing, and aging, and a recently introduced method, ammonium incubation. Each method was assessed considering its underlying principles, effects in application, and respective advantages and disadvantages. This review suggests that successful phytotoxicity mitigation in agricultural waste hinges on reducing the content or activity of phytotoxic substances. Moreover, this study emphasizes that future phytotoxicity mitigation efforts should aim for economic efficiency while maximizing the preservation of the original material volume and weight. This study offers insightful guidance for technical professionals aiming to mitigate the phytotoxicity of agricultural waste, thereby fostering sustainable agricultural practices. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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