Utilization Of Manure Research Articles

Methodological study on carbon sequestration accounting for emission reductions from the whole-chain utilization of livestock and poultry manure

Effective livestock manure management is crucial for carbon neutrality. Scientific accounting methods and integrated management strategies can help guide reductions in carbon emissions and promote green development. To reduce greenhouse gas emissions by livestock manure, this study analyzed current accounting systems and focused on the complete chain of “collection-treatment-storage-use-returning” of manure based on the theoretical framework of greenhouse gas emissions accounting in the IPCC 2019 Guidelines. Combined with a life cycle assessment, the accounting list and boundaries were clarified, and the whole chain of livestock and poultry manure greenhouse gas accounting methodology system was proposed. Using swine breeding as a case study, this study evaluated the carbon emission reduction and sequestration effect of the whole manure chain using a typical technology model and a typical technological framework. It predicted the carbon reduction potential and sequestration benefits of utilizing swine manure in 2025 and 2030 in four scenarios. The findings indicated that the greenhouse gas emission factor of the whole chain of the six typical swine manure utilization modes in China was −48.82–40.54 kgCO2et−1. In 2022, the net greenhouse gas emissions from swine manure in China totaled approximately 2.0 × 107 tCO2e, with manure resource utilization reducing emissions by 3.2 × 107 tCO2e. Our projections suggest that emissions from swine manure in China may range from −1.8 × 107 to 1.3 × 107 tCO2e by 2025 and from −3.1 × 107 to 4.5 × 106 tCO2e by 2030. This can help guide optimal greenhouse gas emission reduction pathways for livestock and poultry farming and aid in the formulation of policies.

Optimizing Lemon Balm (Melissa Officinalis L.) Cultivation: Effects of Different Manures on Plant Growth and Essential Oil Production During Consecutive Harvests

This study examined the impact of organic manures from different sources (poultry, sheep, and cattle) on lemon balm (Melissa officinalis L., Lamiaceae) during different harvests. Manure application increased the photosynthetic pigments levels (chlorophyll-a, 9–41%; chlorophyll-b, 24–60%), biomass (41–60%), and essential oil yield (60–71%). Sheep manure treatment exhibited the highest antioxidant capacity among all the manures tested. Through GC-MS and GC-FID analysis, 10 chemical constituents were identified in the essential oil, accounting together for 91–95% of the total composition. The primary chemical component was geranial (39–46%), followed by neral (28–35%), (E)-caryophyllene (4.7–11%), geranyl acetate (2.7–5.9%), and caryophyllene oxide (1.7–4.8%). The utilization of livestock manures significantly improved the quality of the essential oil in terms of neral and geranial percentages compared to the control. Notably, during mid-August and early October, there was a substantial rise in these valuable compounds. However, a decrease in geranyl acetate and oxygenated monoterpenes resulted in a decline of the antioxidant capacity to 3%. Consequently, it is recommended to utilize essential oils from the second and third harvests for industrial purposes. Overall, the use of livestock manures, especially sheep manure, as a nutrient source for lemon balm cultivation, proves to be a viable approach for producing high-quality essential oils.

The Effect of Farmer’s Cognition on the Inconsistency Between Behavior and Intention in Manure Application

Manure utilization in China is below optimum due to the inconsistency between farmers’ behavior and their intention to apply manure to their crops. With increasing constraints on the availability of chemical fertilizer and their impact on the environment, understanding how farmers’ perceptions affect their intention and behavior toward manure application is an issue for the implementation of sustainable agricultural development. This study uses primary survey data from 653 farmers. A probit model was used to assess the influence of cognition on farmers’ intentions, behavior, and the inconsistency between them in the use of manure application. Heterogeneity analysis was conducted to identify differences between farmers with different education levels and operation scales. The results showed that enhancing subjective norms, perceived behavioral control, and behavioral attitudes could increase their intention and behavior. Furthermore, improving the perceived behavioral control and behavioral attitudes of farmers would reduce the inconsistency between behavior and intention. In addition, some differences were identified in the role of farmers’ cognition with different education levels and operation scales. In general, it is necessary to enhance farmers’ comprehensive cognition of the value of manure through publicity and popularization of technology, reduce farmers’ perceptions about difficulties in applying manure through new policies and subsidies, and stimulate farmers’ enthusiasm to participate in the practice.

Critical stages in pea photosynthesis impaired by tetracycline as an environmental contaminant.

The widespread use of antibiotics in intensive animal husbandry, and the agricultural utilization of manure from such farms, imposes a significant burden on the environment. Consequently, the effects of antibiotics should be studied not only in animals and humans but also in all components of biocenoses and agrocenoses. In our study, we analyze the impact of four different concentrations of tetracycline present in soil (0, 5, 50, and 500mg/kg of soil) on the growth and key photosynthesis parameters of pea seedlings: chlorophyll concentration, aminolevulinic acid concentration, aminolevulinic acid dehydrogenase activity, and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) activity. At the lowest tetracycline concentration, chlorophyll content decreased by 13% compared to the control (0 tetracycline), while at the highest antibiotic concentration, it decreased by as much as 27%. Similarly, the decrease in aminolevulinic acid (a chlorophyll precursor) concentration was significant, amounting to 34%. However, the activity of the dehydrogenase enzyme, which consumes this precursor, decreased even more drastically by 51%, indicating significant disturbances in the light phase of photosynthesis. However, the activity of RuBisCO in pea plants subjected to tetracycline was even more severely affected, dropping by 58%, 69%, and 70% in soils with increasing concentrations of tetracycline. The reduction in enzyme activity could only partially be explained by a less pronounced decrease in the quantity of RuBisCO (large subunit) protein, which amounted to 6.5%, 11%, and 35% for tetracycline concentrations of 5, 50, and 500mg/kg of soil, respectively.

Assessment of Veterinary Antibiotic Use and Occurrence of Veterinary Antibiotics in Livestock Manure from Farms in Rongai Sub-County, Kenya

Veterinary antibiotics are commonly used in livestock rearing to prevent diseases and stimulate growth. The release of antibiotics into the environment has become a significant environmental and public health concern. This research evaluated antibiotic use, livestock treatment, manure utilization, livestock waste treatment methods and antibiotic residues in livestock manure. Questionnaires were administered to 170 farmers rearing both cattle and poultry. Subsequently, 28 livestock manure samples from 15 cattle and 13 poultry rearing farms were collected from various farms to assess concentrations of tetracyclines (Tetracycline, Oxytetracycline) and sulfonamides (Sulfadiazine, Sulfamethoxazole) residues. Residues analysis was done using High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD). Veterinarians were the most preferred in treating both cattle and poultry in farms. Tetracyclines and sulfonamides were the most consumed class of antibiotics among both poultry and cattle rearing farmers. Compost manure and Biogas were the most preferred use of animal waste within farms. Antibiotic presence in samples was detected in 80% and 93% of cattle and poultry manure respectively. Maximum antibiotic concentrations of 16.24 and 15.18 (mg/kg) were recorded in poultry and cattle manure, respectively. There was a statistically significant difference in antibiotic concentrations in poultry and cattle manure (P<0.05). The results of this research are important in monitoring rising concerns about veterinary antibiotics on environmental and public health.

Reducing moisture content can promote the removal of pathogenic bacteria and viruses from sheep manure compost on the Qinghai-Tibet Plateau

Livestock manure contains a high concentration of pathogenic bacteria, viruses, and other harmful microorganisms. The effective elimination of these pathogens is of great significance to the harmless and resource utilization of livestock and poultry manure. Building upon prior research, this study further explored the removal efficiency of pathogenic bacteria and viruses in sheep manure compost on Qinghai-Tibet Plateau under 45 % (M45) and 60 % (M60) moisture content. The results showed that M45 led to a significant increase in the average composting temperature (P＜0.05), a notable reduction in the levels of Salmonella and Coliforms in the compost products, and facilitated the decline in abundance of various pathogens. As composting progressed, the abundance of viruses declined rapidly. Uroviricota was the most dominant viral phylum, and Siphoviridae, Myoviridae, Herpesviridae, and Podoviridae as the predominant viral families. M45 can significantly reduce the diversity and abundance of compost virus community (P＜0.05). The correlation analysis indicated a negative relationship between pathogens and the average temperature and humus content of the compost. In summary, the reduction of moisture content can enhance the biosafety of sheep manure compost products on the Qinghai-Tibet Plateau. These findings provide theoretical basis and technical support for the harmless and resource utilization of sheep manure waste on the Qinghai-Tibet Plateau.

Phosphorus Fraction in Hydrochar from Co-Hydrothermal Carbonization of Swine Manure and Rice Straw: An Optimization Analysis Based on Response Surface Methodology

Livestock manure and crop residues are significant sources of phosphorus. However, the ineffectiveness of current processing technologies often leads to the suboptimal recovery of this phosphorus, causing considerable resource wastage and environmental pollution. Recently, global research has increasingly been focused on the resource recovery of organic waste materials using hydrothermal carbonization technology. This study investigated variations in phosphorus forms in the hydrochar produced from swine manure and rice straw, employing diverse hydrothermal carbonization conditions and applying the Box–Behnken response surface methodology and Hedley’s phosphorus fractionation method. The results indicated that inorganic phosphorus predominates in the hydrochar, with organic phosphorus comprising 5–30% of the total phosphorus. Furthermore, the study found that the available phosphorus content, as measured by NaHCO3 extraction, decreased as the reaction time and temperature of the hydrothermal carbonization process increased. The concentrations of H2O-P and NaHCO3-P fractions decreased with increasing reaction times and temperatures but increased with a higher swine manure-to-straw ratio. Conversely, the concentrations of NaOH-P and HCl-P fractions showed an increasing trend with rising reaction temperature, prolonging reaction time, andusing a high swine manure-to-straw ratio. Consequently, this study offers vital theoretical and practical insights into the resource utilization of livestock manure and crop straw, significantly contributing to the challenges of waste management and environmental sustainability in agriculture.

Virome and metagenomic sequencing reveal the impact of microbial inoculants on suppressions of antibiotic resistome and viruses during co-composting

Co-composting with exogenous microbial inoculant, presents an effective approach for the harmless utilization of livestock manure and agroforestry wastes. However, the impact of inoculant application on the variations of viral and antibiotic resistance genes (ARGs) remains poorly understood, particularly under varying manure quantity (low 10 % vs. high 20 % w/w). Thus, employing virome and metagenomic sequencing, we examined the influence of Streptomyces-Bacillus Inoculants (SBI) on viral communities, phytopathogen, ARGs, mobile genetic elements, and their interrelations. Our results indicate that SBI shifted dominant bacterial species from Phenylobacterium to thermotropic Bordetella, and the quantity of manure mediates the effect of SBI on whole bacterial community. Major ARGs and genetic elements experienced substantial changes with SBI addition. There was a higher ARGs elimination rate in the composts with low (∼76 %) than those with high manure (∼70 %) application. Virus emerged as a critical factor influencing ARG dynamics. We observed a significant variation in virus community, transitioning from Gemycircularvirus- (∼95 %) to Chlamydiamicrovirus-dominance. RDA analysis revealed that Gemycircularvirus was the most influential taxon in shaping ARGs, with its abundance decreased approximately 80 % after composting. Collectively, these findings underscore the role of microbial inoculants in modulating virus communities and ARGs during biowaste co-composting.

PRELIMINARY RESULTS REGARDING THE EFFECTS OF GREEN MANURES ON WHEAT CULTIVATION ON THE ACIDIC SOILS OF THE NORTH-WEST REGION OF ROMANIA

This study addressed the burgeoning interest in ecological agriculture, emphasizing sustainable and regenerative practices. Among these, the utilization of green manures emerged as pivotal for enhancing soil health and augmenting the yield of nutritionally dense crops. Five plant species (triticale, peas, soybeans, sunflower, and rapeseed) were selected for incorporation, sown during the summer, and subsequently integrated into the soil while still in their vegetative phase, preceding the optimal sowing window for wheat. The experiment encompassed three repetitions for the principal crop, of wheat implemented through split-plot design. Each repetition comprised both a fertilized and an unfertilized plot, further sub-divided, with certain segments receiving fungicidal treatment and others left untreated. The experimental setup was situated on an albic luvisol, exhibiting humus content ranging from 1% to 1.8% in the plow layer, coupled with an acidic pH range of 4.2 to 5.3. The trial site was located within the experimental fields of the Plant Protection Laboratory at the Livada Agricultural Research and Development Station, Satu Mare County. The primary aim of this experiment was to evaluate the influence of green manures, including their synergistic interplay with chemical fertilizers (calcium ammonium nitrate 27% N), on wheat. Evaluative parameters encompassed yield metrics, weed infestation levels, disease and pest resistance, along with the quality attributes of the principal crops. Ultimately, the study sought to furnish a encompassing comprehension of the advantages conferred by this regenerative agricultural practice, within the contemporary framework of ecological and agronomic imperatives. In conclusion, the inaugural year of experimenting with green manures did not yield an immediate augmentation in crop yield. However, it became evident that additional fertilization was required to fully harness the benefits of green manures. Encouragingly, the data spotlighted a propitious finding—green manures bolstered the disease resistance of wheat, implying enduring advantages for crop health. Furthermore, the adoption of rapeseed and peas as green manure crops, demonstrated a noteworthy reduction in weeding, affording an economical and pragmatic edge for sustainable agricultural practices. Additionally, when amalgamated with chemical fertilizers, the interaction with green manures evinced an augmented production capacity, underscoring the potential for a synergistic strategy in maximizing crop output. These revelations highlight the significance of a holistic and integrated approach to agricultural methodologies, underscoring the value of amalgamating green manures with judicious fertilization strategies. As we persist in our exploration and refinement of these techniques, the potential for enhancing both productivity and sustainability in our agricultural systems remains considerable, ultimately contributing to a more resilient and efficient food production process.

Impacts of poultry manure and biochar amendments on the nutrients in sweet potato leaves and the minerals in the storage roots

Poultry manure (PM) has demonstrated its potential to enhance crop nutritional quality. Nevertheless, there remains a dearth of knowledge regarding its synergistic effects when combined with wood biochar (B) on the nutrient concentrations in sweet potato leaves (Ipomoea batatas L.) and the mineral content stored in sweet potato storage roots. Hence, a two-year field trial was undertaken during the 2019 and 2020 cropping seasons in southwestern Nigeria, spanning two locations (Owo—site A and Obasooto—site B), to jointly apply poultry manure and wood biochar as soil amendments aimed at enhancing the nutritional quality of sweet potato crop. Each year, the experiment involved different combinations of poultry manure at rates of 0, 5.0, and 10.0 t ha−1 and biochar at rates of 0, 10.0, 20.0, and 30.0 t ha−1, organized in a 3 × 4 factorial layout. The results of the present study demonstrated that the individual application of poultry manure (PM), biochar (B), or their combination had a significant positive impact on the nutrient composition of sweet potato leaves and minerals stored in the sweet potato storage roots, with notable synergistic effects between poultry manure and biochar (PM × B) in enhancing these parameters. This highlights the potential of biochar to enhance the efficiency of poultry manure utilization and improve nutrient utilization from poultry manure. The highest application rate of poultry manure at 10.0 t ha−1 and biochar at 30.0 t ha−1 (PM10 + B30), resulted in the highest leaf nutrient concentrations and mineral composition compared to other treatments at both sites. Averaged over two years, the highest application rate of poultry manure at 10.0 t ha−1 and biochar at 30.0 t ha−1 (PM10 + B30) significantly increased sweet potato leaf nutrient concentrations: nitrogen by 88.2%, phosphorus by 416.7%, potassium by 123.8%, calcium by 927.3%, and magnesium by 333.3%, compared to those in the control (PM0 + B0). The same treatment increased the concentration of sweet potato root storage minerals: phosphorus by 152.5%, potassium by 77.4%, calcium by 205.5%, magnesium by 294.6%, iron by 268.4%, zinc by 228.6%, and sodium by 433.3%, compared to the control. The highest application rate of poultry manure at 10.0 t ha−1 and biochar at 30.0 t ha−1 yielded the highest economic profitability in terms of gross margin (44,034 US$ ha−1), net return (30,038 US$ ha−1) and return rate or value-to-cost ratio (VCR) (263). The results suggested that the application of poultry manure at 10 t ha−1 and biochar at 30 t ha−1 is economically profitable in the study areas and under similar agroecological zones and soil conditions.

Cow manure biochar for activation of peroxymonosulfate to degrade 17β-estradiol: Performance and mechanism

Estrogens are widely detected in the environment and can strongly disrupt the endocrine systems of humans in extremely minute concentrations. Therefore, it is imperative to address possible 17β-estradiol (17β-E2) pollution and explore resourceful utilization methods from cow manure, which contains estrogen. In this study, cow manure biochar (CBC) was successfully prepared and used for the activation of peroxymonosulfate (PMS), attaining a 17β-E2 degradation rate exceeding 90 % within a mere 10 min. Optimal degradation performance was achieved at 2 mg/L 17β-E2 concentration, 2 mM PMS concentration, and 0.2 g/L CBC concentration. Furthermore, the influence of biochar-activated PMS on estrogen degradation was thoroughly explored under various environmental factors. The key reactive oxygen species were identified as O2– and 1O2 by conducting quenching experiments and delayed experiments. This study elucidated the occurrence of direct electron conduction and the generation of reactive oxygen species to degrade 17β-E2. Furthermore, the phenol group on the benzene ring and the hydroxyl group on the cyclopentane in 17β-E2 as the susceptible reaction sites during the degradation process were predicted using density functional theory (DFT). This study presents promising opportunities for the resourceful utilization of cattle manure and the mitigation of environmental pollution by endocrine disruptors.

Sustainable soil management under drought stress through biochar application: Immobilizing arsenic, ameliorating soil quality, and augmenting plant growth

Rise in climate change-induced drought occurrences have amplified pollution of metal(loid)s, deteriorated soil quality, and deterred growth of crops. Rice straw-derived biochars (RSB) and cow manure-enriched biochars (CEB) were used in the investigation (at doses of 0%, 2.5%, 5%, and 7.5%) to ameliorate the negative impacts of drought, improve soil fertility, minimize arsenic pollution, replace agro-chemical application, and maximize crop yields. Even in soils exposed to severe droughts, 3 months of RSB and CEB amendment (at 7.5% dose) revealed decreased bulk density (13.7% and 8.9%), and increased cation exchange capacity (6.0% and 6.3%), anion exchange capacity (56.3% and 28.0%), porosity (12.3% and 7.9%), water holding capacity (37.5% and 12.5%), soil respiration (17.8% and 21.8%), and nutrient contents (especially N and P). Additionally, RSB and CEB decreased mobile (30.3% and 35.7%), bio-available (54.7% and 45.3%), and leachable (55.0% and 56.5%) fractions of arsenic. Further, pot experiments with Bengal gram and coriander plants showed enhanced growth (62–188% biomass and 90–277% length) and reduced arsenic accumulation (49–54%) in above ground parts of the plants. Therefore, biochar application was found to improve physico-chemical properties of soil, minimize arsenic contamination, and augment crop growth even in drought-stressed soils. The investigation suggests utilisation of cow manure for eco-friendly fabrication of nutrient-rich CEB, which could eventually promote sustainable agriculture and circular economy. With the increasing need for sustainable agricultural practices, the use of biochar could provide a long-term solution to enhance soil quality, mitigate the effects of climate change, and ensure food security for future generations. Future research should focus on optimizing biochar application across various soil types and climatic conditions, as well as assessing its long-term effectiveness.

No-tillage with total green manure incorporation: A better strategy to higher maize yield and nitrogen uptake in arid irrigation areas

The efficacy of integrating green manure in arid irrigation regions to enhance maize yield and nitrogen (N) uptake efficiency has been extensively explored. However, limited research has delineated the contribution of green manure N versus soil N on crop N utilization efficiency. This study integrated field experiments with micro-plot experiments to examine green manure (common vetch) management practices for achieving high maize yield and N uptake. In a micro-plot experiment, 15N technology was utilized to label green manure crops. Five treatments were applied in the research methodology: conventional tillage without green manure as the control (CT); tillage with total green manure incorporation (TG); no-tillage with total green manure mulching (NTG); tillage with only root incorporation (T); and no-tillage with removal of above-ground green manure (NT). The results in the micro-plot experiment were the same in the field, and both demonstrated that the utilization of green manure led to a substantial increase in maize yield and nitrogen uptake efficiency (NUPE) compared to conventional tillage (CT). In particular, under NTG, N uptake by maize from green manure was higher than NT and T, accounting for 59.1% of maize N uptake. Furthermore, the application of NTG boosted the NUPE of soil N in maize to 50.7%, which is higher than TG by 5.5%. Meanwhile, it decreased the proportion of soil N in the maize. The difference between NTG and TG was primarily shown in the maize grains. For N transport in the soil, NTG decreased N loss while increasing soil N retention. Also, it facilitated the mineralization of soil organic N before the flowering stage. In conclusion, the adoption of no-tillage with total green manure mulching not only increased N uptake both from green manure and the soil but also decreased the proportion of soil-derived N in maize.

Utilization of Livestock Manure as Biogas and Liquid Organic Fertilizer (LOF) in Sumbermulyo Village, Pesanggaran, Banyuwangi

Biogas is a natural gas produced through anaerobic bacteria breakdown of organic materials. Organic materials can include livestock manure, domestic waste, and other organic waste that bacteria can decomposeunder anaerobic conditions. Sumbermulyo is one of the villages in the Pesanggaran sub-district of Banyuwangi Regency, where the majority of the population works as dragon fruit farmers and goat herders. The current phenomena in the area include the scarcity of subsidized urea fertilizer and Liquified Petroleum Gas (LPG). An alternative approach is to utilize goat manure as a source of methane gas, which can be used as a substitute for LPG. The objective of this community service project is to establish a biogas processing pilot project in the Sumbermulyo Village, Pesanggaran sub-district, which the community can implement. Additionally, it aims to analyze the total N, P, K content in the wet sludge from the digester as liquid organic fertilizer. The method used involves constructing a biogas digester on the land owned by one of the farmer groups and evaluating the gas production. The digester is built using a concrete model (fixed dome) in the shape of an airtight dome. The construction of the digester takes 14 days until it is ready for use. Up to the 10th day of use, thehighest pressure is obtained on day -10, with a pressure of 107,486.76 N/m2 or 1.06 atm. Chemical analysis of the liquid organic fertilizer shows that the total N, P, K content is as follows: 0.032%, 0.009%, 0.144% for the sample from the test digester, and 0.044%, 0.005%, and 0.195% for the sample from the reference digester

Multi-objective optimization for microbial electrolysis cell-assisted anaerobic digestion of swine manure

As a new technology, microbial electrolysis cell-assisted anaerobic digestion (MEC-AD) has been applied to the utilization of swine manure. Methane production and total energy efficiency are both important indicators in MEC-AD; thus, it is necessary to simultaneously optimize methane production and total energy efficiency. In this study, the Box–Behnken design (BBD) was used as the experimental design, the response surface methodology (RSM) and back propagation neural network (BP-NN) methods were used to construct multi-objective models, and the non-dominated sorting genetic algorithm II (NSGA II) was used for multi-objective optimization. The BP-NN model was superior to the RSM model in terms of goodness of fit. Additionally, the relative error between the predicted and experimental values of the Pareto front was determined to be <3%. The maximum methane production and total energy efficiency were 333.97 mL/g total solid and 61.38%, respectively. Therefore, multi-objective optimization of MEC-AD systems may be accomplished using BBD-(BP-NN)-NSGA II.

Material flow analysis of heavy metals in large-scale cattle farms and ecological risk assessment of cattle manure application to fields

This study bridges the knowledge gap pertaining to the pathways of heavy metal accumulation and migration within the industrial chain of large-scale cattle farms. Two such farms in Shaanxi serve as a basis for our exploration into Zn, Cu, Cr, Pb, As, and Cd dynamics. Employing material flow analysis complemented by predictive models, we evaluate the potential ecological risks of arable soil from heavy metal influx via manure application. Our findings indicate that Zn and Cu predominate the heavy metal export from these operations, composing up to 60.00%–95.67% of their total content. Predictive models based on 2021 data reveal a potential increase in Cd soil concentration by 0.08 mg/kg by 2035, insinuating a reduced safe usage period for cattle manure at less than 50 years. Conversely, projections from 2022 data point towards a gradual Cu rise in soil, reaching risk threshold levels after 126 years. These outcomes inform limitations in cattle manure utilisation strategies, underscoring Cu and Cd content as key barriers. The study underscores the criticality of continuous heavy metal surveillance within farm by products to ensure environmental protection and sustainable agricultural practices.

Overview of Resource Utilization of Livestock and Poultry Manure

In recent years, with the development of animal husbandry, more and more livestock and poultry manure has been generated. Currently, the most common methods for treating livestock and poultry manure are anaerobic fermentation and aerobic composting. Aerobic composting is a technology that uses animal manure for high-temperature composting and fermentation to degrade organic matter and convert it into humic substances. Anaerobic fermentation is an energy utilization technology that converts organic matter into combustible gases such as CH4 through the action of anaerobic microorganisms and produces biogas slurry and sludge. This article reviews two treatment methods for livestock and poultry manure, aerobic composting and anaerobic digestion, in order to provide reference for the research of humic acid organic fertilizers.

Effect of aqueous phase from hydrothermal carbonization of sewage sludge on heavy metals and heavy metal resistance genes during chicken manure composting

Livestock manure is often contaminated with heavy metals (HMs) and HM resistance genes (HMRGs), which pollute the environment. In this study, we aimed to investigate the effects of the aqueous phase (AP) produced by hydrothermal carbonization (HTC) of sewage sludge (SS) alone and the AP produced by co-HTC of rice husk (RH) and SS (RH-SS) on humification, HM bioavailability, and HMRGs during chicken manure composting. RH-SS and SS increased the humic acid content of the compost products by 18.3 % and 9.7 %, respectively, and significantly increased the humification index (P < 0.05) compared to the CK (addition of tap water). The passivation of HMs (Zn, Cu, As, Pb, and Cr) increased by 12.17–23.36 % and 9.74–15.95 % for RH-SS and SS, respectively, compared with that for CK. RH-SS and SS reduced the HMRG abundance in composted products by 22.29 % and 15.07 %, respectively. The partial least squares path modeling results showed that SS and RH-SS promoted compost humification while simultaneously altering the bacterial community and reducing the bioavailability of metals and host abundance of HMRGs, which has a direct inhibitory effect on the production and distribution of HMRGs. These findings support a new strategy to reduce the environmental risk of HMs and HMRGs in livestock manure utilization.

Temporal and Spatial Trends in Livestock Manure Discharge and Water Pollution Risk in Chaohu Lake Basin

Assessments of the spatiotemporal distribution of livestock manure and its risk to the watershed are important to prevent water pollution. In this work, the spatiotemporal livestock manure distribution and its risk for the Chaohu lake basin were evaluated based on the excretion coefficient method and ArcGIS technology. In detail, the amounts of livestock manure and its associated pollutants, including chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5), ammonia (NH4+-N), total nitrogen (TN), and total phosphorus (TP), were calculated from 2009 to 2019. Then, the diffusion concentrations of COD, BOD5, NH4+-N, TN, and TP and the water pollution risk index from livestock manure were estimated and predicted for the Chaohu lake basin. The results indicated that the mean amount of livestock manure had reached 1.04 × 107 t in the Chaohu lake basin in the studied decade. The COD, BOD5, NH4+-N, TN, and TP from livestock manure in Feixi and Feidong contributed 54.26% and 54.40% of the total in the whole basin. These results demonstrate the potential pollution risk of livestock manure for the Chaohu lake basin. Moreover, the diffusion concentrations of COD, BOD5, NH4+-N, TN, and TP for the lake basin were from highest to lowest as follows: Feixi &gt; Feidong &gt; Chaohu &gt; Lujiang &gt; Wuwei &gt; Shucheng &gt; Hefei. The water pollution risk index was more than 20 in Feixi and Feidong, indicating that these areas were heavily affected by local livestock manure. The water pollution risk index will be approximately 18 for the Chaohu lake basin in 2030, implying that the Chaohu lake watershed will suffer moderate pollution from animal manure. These results provide scientific support for policymakers to enhance manure utilization efficiency and control livestock manure loss, causing water eutrophication in Chaohu lake basin or other similar watersheds.

A Review on Organic Manure and Plant Growth Promoting Rhizobacteria’s Use in Horticultural Crops

The sustainable and eco-friendly management of horticulture crops has become increasingly imperative in contemporary agricultural practices. This review summarizes the current knowledge on the synergistic utilization of organic manure and plant growth-promoting rhizobacteria (PGPR) to enhance the growth, yield, and overall health of horticulture crops. Organic manures, derived from natural sources such as compost, animal manure, and green manure, offer a sustainable alternative to synthetic fertilizers, providing essential nutrients while promoting soil fertility and structure. PGPR can affect on plant growth by production and releases secondary metabolites, helps in preventing deleterious effects of phyto-pathogenic organisms in the rhizosphere. This will ultimately support for better yield and quality of horticultural crops.