Application Of Organic Wastes Research Articles

Temporal trends of polycyclic aromatic hydrocarbons in soils amended with sludge, compost, and manure in a Scotland pasture: An 8-year field experiment

To optimize the effective utilization of organic waste in agricultural practices, a comprehensive assessment of associated risks and benefits is crucial. This study investigated the impact of three types of organic wastes (sludge, compost, and manure) on polycyclic aromatic hydrocarbons (PAHs) in contaminated soil in a Scottish pasture. The experimental setup comprised 16 plots with four treatments (compost, manure, sludge, and inorganic fertilizer) and four replicates. After eight years of this study, notable disparities in ΣPAH16 concentrations were observed among the different treatments, with compost-amended soil at 378 μg kg−1, sludge-amended soil at 331 μg kg−1, and manure-amended soil at 223 μg kg−1. The concentrations of ΣPAH16 in soil amended with compost and sludge exhibited a linear increase with extended sampling time. Significant changes in ΣPAH16 concentration were evident in the compost treatment plot, with an increase of 20% in the first year and 82% in the eighth year. Risk assessment suggested a low level of health risk from exposure to PAHs at the measured concentrations in the three organic wastes. In conclusion, this study highlights the importance of considering the effects of organic waste amendments on soil PAH levels to make informed decisions in sustainable agricultural practices. It also underscores the need for ongoing research to fully understand the implications of different organic waste applications on soil health and environmental quality.

Combined application of organic wastes and Trichoderma longibraciatum to promote vegetation restoration and soil quality on mining waste dump sites

Combined application of organic wastes and Trichoderma longibraciatum to promote vegetation restoration and soil quality on mining waste dump sites

Residual Effect of Organic Waste Mulching and Intercropping Aerobic Rice with Peanut on Yield Performance of Mungbean Direct-seeded Following Rice on Raised-beds in Lombok, Indonesia

In Indonesia, in the paddy fields, mungbean is generally planted in the dry season as a rotation crop for rice when irrigation water is insufficient for growing rice, so the productivity of mungbean is generally very low. This research aims to determine the impact of cultivation techniques of aerobic-irrigated red rice grown on permanent raised-beds applied with various organic wastes on growth and yield of mungbean direct-seeded following harvest of red rice. The experiment carried out in June-August 2020, was arranged according to Split Plot design, with two treatment factors: techniques of cultivating aerobic-irrigated red rice, as main plots (T1: monocrop; T2: intercropping with peanuts), and application of various organic wastes to the red rice, as subplots (L0: no waste, L1: rice husks, L2: rice husk ash , L3: rice husk ash + cattle manure). The results indicated that techniques of red rice cultivation and application of various wastes to the red rice showed significant interaction effect on pod number and dry filled-pod weight of mungbean direct-seeded following the red rice, in which dry filled-pod weight was highest (14.44 g/clump) in mungbean direct seeded following aerobic-irrigated red rice intercropped with peanuts receiving rice husk ash (T2L2), and lowest (6.74 g/clump) in mungbean direct-seeded following monocropped red rice without organic wastes (T1L0). Both intercropping with peanuts and application of organic wastes to the red rice preceding mungbean, in general, resulted in higher grain yields of mungbean direct-seeded without tillage following harvest of the aerobic-irrigated red rice grown on raised-beds.

Evaluating the efficacy of vermicomposted products in rain-fed wetland rice and predicting potential hazards from metal-contaminated tannery sludge using novel machine learning tactic

The study assessed the ecotoxicity and bioavailability of potential metals (PMs) from tannery waste sludge, alongside addressing the environmental concerns of overuse of chemical fertilizers, by comparing the impacts of organic vermicomposted tannery waste, chemical fertilizers, and sole application of tannery waste on soil and rice (Oryza sativa L.) plants. The results revealed that T3, which received high-quality vermicomposted tannery waste as an amendment, exhibited superior enzymatic characteristics compared to tannery sludge amended (TWS) treatments (T8, T9). After harvesting, vermicomposted tannery waste treatment (T3) showed a more significant decrease in PMs bioavailability. Accumulation of PMs in rice was minimal across all treatments except T8 and T9, where toxic tannery waste was present, resulting in a high-risk classification (class 5 < 0.01) according to the SAMOE risk assessment. Results from Fuzzy-TOPSIS, ANN, and Sobol sensitivity analyses (SSA) further indicated that elevated concentrations of PMs (Ni, Pb, Cr, Cu) adversely impacted soil-plant health synergy, with T3 showing a minimal risk in comparison to T8 and T9. According to SSA, microbial biomass carbon and acid phosphatase activity were the most sensitive factors affected by PMs concentrations in TWS. The results from the ANN assay revealed that the primary contributing factor of toxicity on the TWS was the exchangeable fraction of Cr. Correlation statistics underscored the significant detrimental effect of PMs' bioavailability on microbial and enzymatic parameters. Overall, the findings suggest that vermicomposting of tannery sludge waste shows potential as a viable organic amendment option in the near future.

Enhanced phytoremediation of metal contaminated soils aimed at decreasing the risk of antibiotic resistance dissemination

The enhanced phytoremediation of metal contaminated soils holds great promise for the recovery of soil health and functionality, while providing a range of co-benefits, from an environmental and human health perspective, derived from the revegetation of the degraded sites and the concomitant delivery of ecosystem services. Due to diverse evolutionary co-selection mechanisms between metal resistance and antibiotic resistance in bacteria, metal contaminated soils are considered potential reservoirs of antibiotic resistant bacteria (ARB) which can contribute to the existing antibiotic resistance crisis. During the enhanced phytoremediation of metal contaminated soils, the application of organic wastes (e.g., manure, slurry, sewage sludge) as soil amendments can aggravate the risk of antibiotic resistance spread, because they often contain ARB which harbor antibiotic resistance genes (ARGs) that can then be propagated among soil bacterial populations through horizontal gene transfer (HGT). Due to the magnitude and criticality of the antibiotic resistance crisis, as well as the higher risk of spread and dispersal of ARB and ARGs (they make copies of themselves) compared to metals, it is proposed here to aim enhanced phytoremediation strategies towards decreasing the soil resistome (and, hence, the risk of its potential link with the human resistome), while reducing total and/or bioavailable metal concentrations and restoring soil health and the delivery of ecosystem services. To this purpose, a decalogue of practices is tentatively suggested. Finally, a proper management of plant and soil microbial compositions is a most crucial aspect, together with the selection of the right organic wastes and phytoremediation practices.

Residual phosphorus availability after soil application of different organic waste in varying soil P status soils

Transformations of applied phosphorus (P) fertilizer to inaccessible residual soil P is the main cause of inadequate P availability to plants in the majority of the cultivated soils. This study investigated the effect of organic wastes (rice-residue biochar, farmyard manure (FYM), poultry manure (PM), green manure (GM), and wheat straw (WS) on residual-P mobilization and its bioavailability in maize crops under different P status soils. Surface soil samples of ‘medium-P’ (12.5–22.5 kg P ha−1) and ‘high-P’ (22.5–50.0 kg P ha−1) status soils were collected from a long-term differential P fertilization experiment on maize-wheat rotation and were subjected to examine P adsorption/desorption, phosphatase activity and microbial biomass P (MBP) after incubation with organic amendments of varying elemental composition. The incorporation of organic manures decreases P sorption with maximum decrease in FYM-treated soils, indicating increased P concentration in soil solution. In contrast, WS due to its wider C/P ratio increased P sorption and did not produce any significant impact on the bioavailability of P. High-P status soils witnessed lower P sorption than medium-P soils. The MBP increased in the order of PM > FYM > GM > WS > biochar irrespective of soil P status. The availability and mobility of residual-P with FYM and PM was significantly higher than that of residual-P from biochar, GM and WS. Organics with wider C/P ratio immobilize bioavailable P in the short term regardless of soil P status.

Experimental and molecular dynamics simulation study on solubility characteristics of chloride and sulfate salts in supercritical water

Supercritical water gasification (SCWG) shows great potential in converting organic waste into hydrogen-rich gas with low environmental impacts and significant economic benefits. However, a comprehensive analysis of the solubility of inorganic salts in supercritical water is still scarce, hindering the application of SCWG high-salt organic waste. In this work, solubility characteristics of chloride and sulfate salts in the range of 673 K to 773 K and 22 MPa to 30 MPa are explored using both experimental and molecular dynamics simulation methods. The results indicate that salt solubility in supercritical water increases with decreasing temperature and increasing pressure. The solubility of cations and anions follows the order of K+ > Na+ > Ca2+ and Cl- > SO42-, respectively. The addition of type I salt significantly enhances type II salt solubility in the ternary system. This work is expected to offer a reference for the optimization design of SCWG reactors.

Dampak Pupuk Organik Cair dan Kompos IPAL Karet Terhadap Pertumbuhan Bibit Kelapa Sawit (Elaeis Guineensis Jacq) di Main Nursery

Oil palm plants (Elaeis guineensis Jacq) are one of the important commodities in the plantation crop industry, capable of providing economic value as a source of foreign exchange income for the country. The increase in oil palm area is also accompanied by an increase in damaged plants (TR/TTM). So it is necessary to rejuvenate the plants to get quality seeds. The aim of this research was to determine the effect and best dose of Eco Farming liquid organic fertilizer treatment with rubber wastewater treatment plant sludge compost on the growth of oil palm (Elaeis guineensis Jacq.) seedlings in the main nursery. This research was carried out at the Teaching and Research Farm, Faculty of Agriculture, Jambi University and lasted for 3 months, starting in September-November 2022. This research used a Completely Randomized Design (CRD) with 5 treatments, namely: k0 = 40 mL.L-1 Eco fertilizer water Farming, k1 = 30 mL.L-1 Eco Farming fertilizer water + 100 g compost from waste sludge from WWTP, k2 = 20 mL.L-1 water from Eco Farming fertilizer + 200 g compost from waste sludge from WWTP, k3 = 10 mL.L-1 Eco Farming fertilizer water + 300 g of WWTP sludge waste compost, k4 = 400 g of WWTP sludge waste compost. The variables observed included seed height (cm), increase in tuber diameter (mm), increase in number of leaves (strands), shoot dry weight (g), root dry weight (g), ratio of root shoot and root volume (ml). The results of the research showed that the application of Eco Farming liquid organic fertilizer and waste compost from rubber wastewater treatment plant sludge was able to increase growth in the variables of seed height, root dry weight and root volume. However, it has not been able to increase the increase in tuber diameter, increase in number of leaves, shoot dry weight and root shoot ratio. Treatment of 10 mL.L-1 of Eco Farming fertilizer water + 300 g of IPAL waste sludge compost gave the best average growth of 6 month old oil palm seedlings in the main nursery.

Effect of Application of Liquid Organic Fertilizer of Pineapple Peel Waste on Growth and Production of Red Lettuce Plants (Lactuca sativa var. Crispa)

This study aims to determine the effect of giving the optimal concentration of pineapple peel liquid organic fertilizer on the growth and production of red lettuce plants (Lactuca sativa var. Crispa)". This research was conducted in Modong Village, Tulangan Subdistrict, Sidoarjo Regency and continued at the Agrotechnology Laboratory of Muhammadiyah Sidoarjo University. The research was conducted from December 2022 to January 2023. This study uses a Randomized Group Design (RGD) with a single factor, namely the concentration of liquid organic fertilizer application of pineapple peel waste. The concentrations of liquid organic fertilizer of pineapple peel waste were 100 cc/l; 150 cc/l; 200 cc/l; 250 cc/l; 300 cc/l; 350 cc/l; 400 cc/l. The data obtained were processed using ANOVA, if there is a difference between treatments then it will be followed by 5% tukey test. The variables observed were plant height, number of leaves, wet weight, dry weight, root length, and harvest index. Based on the results of the study, it can be concluded that the application of liquid organic fertilizer pineapple peel waste significantly affects the observation variables of plant height, number of leaves, wet weight, dry weight and root length. While it is not significantly different on the observation variable of harvest index. The optimal application of liquid organic fertilizer pineapple peel waste is with a concentration of 250 cc/l (N4).

Crop – Livestock integration via maize straw recycling increased carbon sequestration and crop production in China

CONTEXTAgriculture production is crucial in mitigating climate change while securing food productivity. However, the impact of the practices such as organic waste (crop residue and animal manure) recycling or integrating crop-livestock system on productivity and carbon sequestration was unclear. OBJETIVEThis study presents a potential crop-livestock model to enhance carbon sequestration from a whole system perspective. This study aimed to (i) examine the effect of different organic waste recycling on contents of SOC, MBC, and EOC at a depth of 0–60 cm of soil; (ii) analyze the sequestration potential of SOC for different organic wastes recycling models using the substance flow balance method; and (iii) propose suitable organic wastes recycling models for crop and livestock production system in China from the whole-system perspective. METHODSThis study conducted a comparative assessment of carbon sequestration of diverse organic wastes in China using a four-year field experiment and substance flow balance method. The field experiment involved three types of organic waste (raw maize straw (MS), biogas slurry (BS), dairy manure (DM)) and two fertilizer application treatments (unfertilized control (CK), and only chemical fertilizer (CF)). Based on the field results, the carbon flow for different organic waste recycle models was compared using the substance flow approach. RESULTS AND CONCLUSIONSThe content and sequestration of SOC and its fractions increased with the application of organic wastes. The effect of organic wastes on SOC sequestration followed the order DM > MS > BS. Additionally, organic waste, especially DM, significantly increased the sequestration of MBC and EOC by 198% and 359%, respectively, compared to CF. The SOC, MBC, and EOC sequestration rates for DM treatment were 2.9–3.2, 0.3–0.6, and 2.7–3.0 Mg ha−1 yr−1, respectively. On a per-crop yield basis, the “crop straw-livestock-manure-field” model contributed about six times more for SOC sequestration than CF. Future estimation showed that the DM model could reduce chemical fertilizer use by 36% compared to CF, resulting in lower costs. Therefore, the “crop straw-livestock-manure-field” system benefits carbon sequestration and emphasizes the importance of expanding the organic waste management chain. SIGNIFICANCEThe findings have significant implications for the agricultural system, highlighting the importance of integrating the “crop straw-livestock-manure-field” model for carbon sequestration and sustained productivity. The results demonstrate that this model has successfully increased carbon sequestration in the agricultural system. These findings provide an essential option for achieving carbon neutrality in China and promoting sustainable development in agricultural system in other regions.

Risk of Heavy Metal Contamination in Vegetables Fertilized with Mushroom Residues and Swine Manure

Mushroom residues and swine manure are two common types of agricultural waste that are often returned to fields as organic fertilizers. However, the environmental risks of their reclamation, such as heavy metal pollution, have been less studied. To investigate the potential risks of heavy metal contamination in soils and vegetables after continuously applying mushroom residues and swine manure, field experiments of four consecutive vegetable rotations were conducted in the Qingpu District of Shanghai, Southeast China, from 2019 to 2021. The concentrations of heavy metals in soils continuously fertilized with mushroom residues and swine manure gradually increased. The organic matter content in the soils exhibited a significant correlation with the concentrations of Cu, Zn, Pb, and Cd (p &lt; 0.01), suggesting that the increase in heavy metals is attributed to the use of organic waste. In particular, the application of swine manure increased Cu, Zn, Pb, and Cd concentrations in the soils by 118.3%, 54.9%, 57.6%, and 122.2%, respectively. Moreover, the application of organic waste raised the risk of the bioaccumulation of toxic metals, such as Cd, in vegetables. The Cd concentration was significantly and positively correlated with Zn in the edible parts of vegetables (p &lt; 0.05). The recycling of swine manure more significantly enhanced Cd concentrations in the edible parts of green pepper (Capsicum annuum), eggplant (Solanum melongena), Brassica chinensis, and lettuce (Lactuca sativa), which were 2.53, 1.55, 1.66, and 1.62 times that of the non-fertilizer control (CK), respectively. Although the increase in heavy metals in the soils and vegetables was still mild when compared with the set thresholds of soil and food safety after the four vegetable rotations, the trend of increase in toxic heavy metals in the food chain with a continuous application of organic waste should be carefully considered.

Pecan Biomass and Dairy Manure Utilization: Compost Treatment and Soil In-Situ Comparisons of Selected Pecan Crop and Soil Variables

A compost program was developed on-farm, utilizing tree trimming biomass from a commercial pecan farm comprised of 14-year-old improved cultivar Western Schley pecan (Carya illinoinensis) tree stands. The direct soil application of shredded pecan tree biomass (P) and dairy manure (M) served as a standard on-farm practice. Three composts were produced using P and M with varying levels of other inputs and processing. The PM compost contained only P and M and its production included only weekly turning and watering. The other two composts included P, M, unfinished compost, and clay inputs, and either additional landscaping residues (A) (designated PM/A compost) or “green chop” (on-farm grown legumes, G) (designated PMG/A compost); production of PM/A and PMG/A composts included additional processing steps intended to improve compost quality per the recommendations of a compost consulting company. Soil samples were taken at three depths (0–15 cm, 15–30 cm, 30–61 cm) in November 2017 from the 1.3 ha study plot of trees. The standard practice and compost treatments were applied at approximately 18 t/ha in January 2018 and 2019 at a 15 cm depth. Soils were re-sampled at the end of the two-year study. Composts and soils were analyzed for: pH, sodium adsorption ratio (SAR), electrical conductivity, and total carbon, organic matter, magnesium, calcium, sodium, nitrate-N, total Kjeldahl nitrogen (TKN), available phosphorus, potassium, zinc, manganese, iron, and copper contents. Pecan tree leaf nutrient content, stem water potential, and leaf greenness were also measured one and two years after soil amendment application. While increases in several soil properties were observed with the treatments, only available phosphorus content was significantly different between pre and post at all depths. Electrical conductivity, TKN, Fe, Cu, SAR, and Na content showed significant differences in the upper soil layers. No differences in leaf properties were observed. This suggests that there are minimal differences in the outcomes for compost application compared to in-situ biomass application; additional compost inputs and processing did not provide additional short-term soil or plant benefits for pecan tree production. More work is needed to determine if there are long-term benefits to soil quality, plant health and performance, or carbon sequestration that impact the economic and environmental decision-making processes for composting and application of local organic wastes.

ORGANIC MULCHING TO CONSERVE SOIL NUTRITIONAL QUALITY AND ENHANCE WHEAT YIELD

Nutritional degradation of soil is an alarming issue of present agriculture due to extensive farming to overcome food security. A field experiment was conducted during rabi season 2021- 22 at the research area of Arid Zone Research Centre (AZRC), Dera Ismail Khan to assess the efficiency of two types of mulches (farm manure (FM) and wheat straw (WS) to conserve soil nutrient capacity with improving wheat yield. Wheat variety “AARI-2011” was sown @ 150 kg/ ha and fertilizers were applied @ 120-90-60 kg/ha of NPK using Randomized Complete Block Design. The soil was sampled from 0-60 cm depth after the wheat crop harvesting and was examined for soil NO3 -1 nitrogen, available P and extractable K. Wheat straw and grain yields were taken at maturity showing significant improvement with increasing mulch application. Plant grain samples were also analyzed for nutrient (N, P and K) concentrations. The data were statistically analyzed using the ANOVA technique and the means of the treatments were compared using HSD (Tuckey’s) test with 5% significance. An eloquent increase in nutritional components NO3 -1, P and K of the top 30 cm soil layer and crop grain was observed. It was concluded that the application of organic wastes as soil cover not only conserves soil but also enhances its productivity. Therefore, it is recommended to use mulching materials to conserve soil and enhance productivity.

Application of organic wastes to subsoil materials can provide sustained soil quality in engineered soil covers for mine tailings rehabilitation: A 7 years study

Improper disposal or poor management practices at mine Tailings Storage Facilities (TSF) can give rise to fugitive emissions with risk to both the surrounding environment. Establishing sustainable vegetation covers (rehabilitation) on TSFs is a critical objective and effective management strategy to mitigate pollution risk. Although direct revegetation is a potential strategy, tailings can exhibit properties such as extreme pH, salinity, elevated metal content, deficiency of nutrients and organic matter that inhibit vegetation establishment and necessitate the provision of a cover soil medium (≥ 30 cm). This requires a high amount of topsoil sourcing, which is often in limited supply at mine sites because of degradation, contamination, or previous removal. Moreover, materials often used as a soil cover for tailings may not favour plant establishment and development due to the poor soil structure and the low level of organic matter and nutrient content.Thus, improvement of substrate physiochemical characteristics by using organic and/or inorganic amendments is needed to promote plant establishment and drive soil processes. While several studies have assessed the feasibility of different plant growth media (soils) they are often based on short-term evaluation in greenhouse and lack the longer term implications of field based studies.Soil cover materials were evaluated using 1 m3 plots at a Pb/Zn TSF. Treatments included tailings, subsoil and subsoil amended with Compost like Output (CLO) and Spent Mushroom Compost (SMC). Following 7 years' revegetation, soil samples were taken at two depths (0–10 cm and 10–20 cm) and pH, salinity (EC), structure, nutrient and metal content were determined. Vegetation nutrient content was determined after 1 yrs. growth (2015) and again at 7 yrs. (2021).Bare tailings and subsoil displayed poor physico-chemical properties, whereas SMC or CLO amendment, improved physical characteristics and nutrient content both in soil and in vegetation, showing that the benefits of organic amendment to subsoil materials for rehabilitation are effective in the long-term. Moreover, results showed a higher content of C, N and P in all treatments at the depth 0–10 cm than at 10–20 cm, highlighting the role played by the rhizosphere. While lower vegetation nutrient content was recorded in the in the 2021, in some cases below deficiency criteria, results highlight the need for rehabilitation criteria specific rather than applying standard agronomy guidelines.

The Effect of Organic Waste Applications on Soil Aggregation and Soil Organic Carbon Fractions

ABSTRACT In this study, organic wastes obtained from different sources (Olive Oil Solid Waste-OSW, vermicompost-VC, farmyard manure- FYM) were applied in different doses (0, 1, 2, 3%) and the aggregation status of the soils and soil organic carbon (SOC) fractions (organic carbon-OC, activated carbon-AC, microbial biomass carbon-MBC) were investigated. In this study, unlike other studies, the contribution of organic materials to SOC fractions and which of these fractions have a significant relationship on aggregation have been revealed. In the study, the aggregate stability (AS) and mean weight diameter (MWD) properties of the soils increased by 12% and 8% compared to the control with 3% organic waste application. It was determined that OSW and FYM were more effective than VC on aggregate development of soils. In addition, statistically significant differences were found with organic material application on SOC fractions. The highest increase was detected in the microbial biomass carbon content (69%) compared to the control. While a high positive correlation was determined between aggregate stability and carbon fractions, the relationship between C fractions and AS was listed as organic carbon > microbial biomass carbon > activated carbon (r: 0.96, 0.94, 0.68; p < .05). The effects of organic wastes applied at 2 and 3% dose levels, the obtained AS, MWD, and OC contents showed significant variability depending on the differences in the wastes. As a result of the study, it was evaluated that organic waste application was effective in the aggregate development of soils. In addition, it was determined that the most effective SOC fraction in increasing the aggregate stability of soils was OC. On the other hand, it was determined that the more unstable activated carbon contributed to the increase of AS at lower levels.

Insight into the structural feature, ash transformation behavior, and alkali metal heat release characteristic of industrial lignin via experimental and equilibrium evaluation

The release characteristics of inorganic minerals during the thermochemical transformation of organic solid wastes are one of the key issues for their resource utilization. This study concentrated on the chemical structure of three kinds of industrial lignin and the release pattern and mechanism of alkali metal elements during heat treatment by means of 13C NMR, FTIR, XRD, SEM, and chemical thermodynamic equilibrium simulation. The microstructures of the three lignin samples were studied using 13C NMR and FTIR. The three lignin samples contained much more aliphatic and aromatic carbon than carbonyl carbon, and the aliphatic carbon moieties contained the most oxygenated carbon. The lignin samples mainly had aromatic molecular structures with aromaticity (fa) of 55.76% (sodium lignin sulfonate, SL), 52.62% (calcium lignin sulfonate, CL), and 63.93% (de-alkalized lignin, DL), respectively. Carbonyl content in DL was lower than lignin sulfonate SL and CL. The benzene ring content of SL was lower than the other two lignin samples. Na+ metal salts promoted the pyrolysis of lignin samples, while Ca2+ metal salts inhibited the pyrolysis of lignin samples. Microstructural studies showed that the structure of SL evolved from columnar and granular coexistence breaking into filamentous protrusions and lamellar structures with the increase of pyrolysis temperature. The CL and DL samples became ash presented in granular state and the particle size continued to become smaller with increasing temperature as the distribution gap became larger. The chemical thermodynamic equilibrium calculations showed that the variation in the initial concentrations of Na+ and Ca2+ in the three lignin samples led to different release characteristics of the three lignin samples. Na+ release rate was higher than that of Ca2+, and the valence state of the metal ions was an important reason for this phenomenon. This study provides data support and theoretical basis for the migration and release pattern of alkali metal during the thermal conversion reaction of organic solid waste applications.

Sustainable agricultural use of sewage sludge: impacts of high Zn concentration on on Folsomia candida, Enchytraeus crypticus, Lactuca sativa, and Phaseolus vulgaris.

Zinc (Zn) is an essential micronutrient for plants and an important component for maintaining soil quality. Commonly found in the soil due to anthropogenic activities, such as industrialization and application of organic waste as fertilizers, in high concentrations, Zn may induce soil toxicity, affecting important communities, such as edaphic fauna. Despite its high concentrations found in the environment, Zn bioavailability can be affected by the type of soil, organic matter content and pH. In this work, Zn had its toxicity evaluated in a natural tropical soil, sampled in São Paulo-Brazil, for two soil invertebrates (Folsomia candida, Enchytraeus crypticus) and two seeds (Lactuca sativa and Phaseolus vulgaris), through ecotoxicological tests. The invertebrate E. crypticus was exposed to Zn concentrations of 10.0 (T1); 100.0 (T2); 150.0 (T3); 200.0 (T4); 400.0 (T5) mg Zn kg-1 of dry soil, while F. candida, L. sativa and P. vulgaris were exposed to Zn concentrations of 100.0; 200.0; 400.0; 800.0 (t6); 1600.0 (t7); and 2000.0 (t8) mg Zn kg-1 of dry soil. The outcome evaluated were seed germination, for L. sativa and P. vulgaris, and reproduction, for F. candida and E. crypticus. The EC50 obtained for E. crypticus, F. candida, L. sativa, and P. vulgaris were 261.5, 1089.7, 898.5, and 954.5mg Zn kg-1 of dry soil, respectively, being E. crypticus the most sensitive organism, and only at the highest Zn's concentrations the organisms' reproduction and seeds' germination showed a statistically significant inhibitory effect (p < 0.05). Therefore, this work's results showed that Zn does not present significant toxicity for the tested soil organisms and seeds and that at 100mg Zn kg-1 of dry soil it can be beneficial to F. candida and E. crypticus' reproduction and L. sativa's germination. These results imply that the presence of Zn in low concentrations, both in soil and biofertilizers, such as sewage sludge, not only is not a concern, but it can even benefit certain crops and functions of edaphic organisms, which may contribute to the engagement of sustainable agricultural practices and the quest for food security.

Modeling of Organic Waste Classification as Raw Materials for Briquettes using Machine Learning Approach

The existence of organic waste must be utilized by the community so that it does not only end up in landfills but can also be processed into something constructive so that it is useful and has high economic value. Organic waste can be converted into raw materials to manufacture of biomass briquettes. Machine learning techniques were developed for technological applications, object detection, and categorization. Methods with artificial reasoning networks that use a number of algorithms, such as the Naive Bayes Classifier, will work together in determining and identifying certain characteristics in a digital data set. The manufacturing method goes through several processes with a waste classification model as a source of learning data. The image data is based on five types: coconut shells, sawdust, corn cobs, rice husks, and plant leaves. The research aims to identify and classify types of waste both organically and non-organically so that it will make it easier to sort waste. The results of testing the organic waste application from digital images have an accuracy rate of 97%. The model design carried out in training data is useful for producing a data model.

Intercropping with peanuts and long-term application of organic wastes improve mycorrhizal development and growth of red rice under aerobic irrigation systems

Effect of additive intercropping with peanuts and long-term application of organic wastes on the development of arbuscular mycorrhizal and red rice growth under aerobic irrigation systems on raised beds has been studied through a field experiment conducted at Beleke Village, West Lombok, Indonesia, from October 2020 to February 2021. The experiment was designed using Split Plot, with three blocks and two treatment factors: intercropping with peanut (T1= monocropped rice, T2= rice-peanut intercropping) as main plots, and application of organic wastes (L0= no waste, L1= rice husk, L2= rice husk ash, L3= rice husk ash + cattle manure) as subplots. Data were analyzed with Analysis of Variance (ANOVA) and Tukey’s HSD at 5% levels of significance using CoStat for Windows ver. 6.303. The results indicated that intercropping with peanuts significantly increased plant height, tiller number, and growth rate of plant height by 25, 26, and 50%, respectively. Both intercropping with peanuts and application of organic wastes such as rice husk ash significantly increased mycorrhizal spore number (by 190 and 21%, respectively). Intercropping red rice with peanuts together with the application of rice husk ash resulted in the highest growth rates of tiller number (0.69 tillers/day) and leaf number (3.16 leaves/day) of red rice.

Predicting the short‐ and long‐term effects of recycling organic wastes in cropping systems with the PROLEG tool

AbstractRecycling organic wastes (OWs) in agriculture may increase soil organic carbon (SOC), improve soil chemical, physical and biological properties and make mineral fertilizer savings possible. Some drawbacks are related, for example, to N losses, soil contamination or greenhouse gas (GHG) emissions, and may counterbalance the interest in OW recycling. Some of these effects are only noticeable after repeated applications over several years and depend on OW type, on their insertion in cropping systems (e.g. rate, period) and on pedoclimatic conditions. The optimization of OW recycling should promote its positive effects and limit its negative effects. Various simulation tools can predict some OW effects and help with this optimization. However, despite many existing tools, dedicated tools with a multicriteria approach to OW effects and the ability to consider various OWs, soils, climates and cropping systems are still missing. We developed the PROLEG tool to predict the short‐ and long‐term multiple effects of OW application in agriculture at the field scale. The tool combined the soil‐carbon model AMG to predict SOC changes, the soil‐crop model STICS to predict N supply and N losses, some pedotransfer functions to predict the evolution of some soil properties related to SOC and simple balance equations to predict mineral fertilizer needs, GHG balance, soil contamination with trace metals and economic results. The tool also embedded many parameter tables, especially related to the characteristics of diverse OWs. The tool required easily accessible soil properties and a description of the cropping systems in a simple spreadsheet. It automatically computed mean and detailed output variables in tables and figures. We illustrated the use of the tool with a simple case study. The tool has already been used with farmers to design new cropping systems and to support public policy related to anaerobic digestion.