Improvement of pig manure compost lignocellulose degradation, organic matter humification and compost quality with medical stone

Improvement of humification and mechanism of nitrogen transformation during pig manure composting with Black Tourmaline

This study aimed to reveal the role of Black Tourmaline (TM) in the humification enhancement and the mechanism of nitrogen transformation during pig manure composting. Results showed that adding TM promoted the maturity and improved the humification degree by 20.13-33.77%. And TM was beneficial for the transformation from NH₄⁺-N to amino organic nitrogen to fix more nitrogen in compost mass. Then NH₃ and N₂O volatilization were decreased by 22.88-34.76% and 69.79-87.47% by comparison with the control, and the minimum value in nitrogen loss (26.78%) was observed in the 10% TM blended treatment. Furthermore, through RDA analysis, the protease an upmost contributor to nitrogen transformation. Meanwhile, total organic carbon was dominant factor affected enzymatic activities. Therefore, 10% TM was suggested to reduce nitrogen loss and increase humification in this research. Deeply related research in gene and specific addition amounts of TM will be investigated later.

An analysis of the versatility and effectiveness of composts for sequestering heavy metal ions, dyes and xenobiotics from soils and aqueous milieus

The persistence and bioaccumulation of environmental pollutants in water bodies, soils and living tissues remain alarmingly related to environmental protection and ecosystem restoration. Adsorption-based techniques appear highly competent in sequestering several environmental pollutants. In this review, the recent research findings reported on the assessments of composts and compost-amended soils as adsorbents of heavy metal ions, dye molecules and xenobiotics have been appraised. This review demonstrates clearly the high adsorption capacities of composts for umpteen environmental pollutants at the lab-scale. The main inferences from this review are that utilization of composts for the removal of heavy metal ions, dye molecules and xenobiotics from aqueous environments and soils is particularly worthwhile and efficient at the laboratory scale, and the adsorption behaviors and effectiveness of compost-type adsorbents for agrochemicals (e.g. herbicides and insecticides) vary considerably because of variabilities in structure, topology, bond connectivity, distribution of functional groups and interactions of xenobiotics with the active humic substances in composts. Compost-based field-scale remediation of environmental pollutants is still sparse and arguably much challenging to implement if, furthermore, real-world soil and water contamination issues are to be addressed effectively. Hence, significant research and process development efforts should be promptly geared and intensified in this direction by extrapolating the lab-scale findings in a cost-effective manner.

Role of the proportion of cattle manure and biogas residue on the degradation of lignocellulose and humification during composting

The effects of different proportions of cattle manure (CM) and biogas residue (BR) on the degradation of lignocellulose and humification during composting were investigated. The results showed that increasing the CM content prolonged the thermophilic period duration, thus promoting organic matter degradation and enhancing the humification degree during composting. Compared with the initial compost, the cellulose content decreased 3.90%-22.81%. The addition of CM increased humic acid content by 17.21%-26.02% compared with the control. The excitation-emission matrix (EEM) fluorescence spectroscopy analysis indicated that a higher CM content was conducive to the formation of protein-like substances, but a disadvantage for humic substances. The cell viability decreased as CM content increased. The redundancy analysis (RDA) demonstrated that proportions of CM and BR were positively correlated with cellulose content and negatively correlated with cell viability and the content of lignin. The results suggest that adding 6.7% CM was optimal for BR composting.

Food waste composting - Is it really so simple as stated in scientific literature? - A case study

Food waste has recently gained much worldwide interest due to its influence on the environment, economy and society. Gathering and recycling of food waste is the essential issue in the waste management and the interest in processing food waste arises mainly out of influence of the processes of food putrefaction on the environment. Composting of food waste encounters a number of technical challenges, arising weak physical structure of food waste with weak porosity, high content of water, low carbon-to-nitrogen relation and fast hydrolysis and accumulation of organic acids during composting. Therefore, the aim of this study was to investigate the challenges facing installations intended for food waste composting, with the purpose to their optimization with use of appropriate additives. Physico-chemical, biochemical characteristics and phytotoxicity of the produced compost has been measured. Two additives (20% biochar and 20% sawdust) were chosen from experimental variants I-XII containing different additives (biochar, Devonian sand, sawdust) in diverse concentration. The use of selected additives seems to slightly increase potential of hydrogen value and carbon-to-nitrogen ratio, while decreasing electrical conductivity in comparison with control sample. The results obtained also show that the addition of biochar leads to an increase dehydrogenase, phosphatase and arylsulphatase activities and addition of sawdust has a positive effect on beta-D-glucosidase, protease, phosphatase and arylsulphatase activities. The phytotoxicity test shows that the compost made of food waste (control sample) and with addition of biochar is toxic to plants. By contrast, the addition of sawdust shows that the compost was not phytotoxic. In conclusion, the addition of additives does not provide unambiguous results in terms of the quality of the final product in all monitored parameters. Therefore, we can state that food waste was reduced and hygienized, and that the final product does not meet conditions for mature compost.

Effects of external additives: Biochar, bentonite, phosphate, on co-composting for swine manure and corn straw

Composting is an acceptable and economically feasible process for recycling agricultural biomass waste. The addition of external additives to adjust the process of composting has been attracted lots of research attention. To investigate the effects of external additives on nutrients transformation process of composting, a laboratory reactors scale co-composting based on swine manure and corn straw (CK) with the additives of phosphate (MP), calcium bentonite (CB) and biochar (BC) were performed for 30 days. The results showed the addition of phosphate and biochar could contribute to accelerating temperature rise and shorten the thermophilic phase. The germination index (GI) of MP and BC achieved 180% and 150%, respectively. The excitation-emission matrix (EEM) demonstrated the intensities of the peak C (humic acids) of the MP treatment was 829.5, and the P_V,n/P_III,n value (9.59) of MP treatment was particularly higher compared to other three treatments according to the fluorescence regional integration (FRI) analysis. The Fourier Transform Infrared spectroscopy (FTIR) indicated the rate of decomposition of aliphatic C substances was higher than that of aromatic C substances. According to the X-ray diffraction (XRD) spectra results, characteristic peaks at both 16° and 22° were decreased, indicating cellulose and amorphous components were degraded. It further proved the formation of struvite component in MP treatment. Therefore, based on the maturity indicators, EEM and XRD results, phosphate is an efficient additive and recommended for swine manure and corn straw co-composting.

Effects of Bacillus subtilis on carbon components and microbial functional metabolism during cow manure-straw composting

This study is the first to investigate the changes in the composting process and carbon conversion in a cow manure-straw compost matrix with Bacillus subtilis added at four different levels (0, 0.5%, 1%, and 2% w/w compost), and to explain the mechanism responsible for carbon conversion through microbial functional metabolism. Inoculation with Bacillus subtilis at 2% had the best effect on fermentation among all treatments, but it inhibited the synthesis of total organic carbon and humus. Bacillus subtilis at 0.5% reduced mineralization in the cooling and maturity stages of composting, and enhanced the humification of carbon. The total organic carbon and humic sequence contents were significantly higher with Bacillus subtilis at 0.5% (12.5% and 20.2%, respectively) than Bacillus subtilis at 2% (P < 0.05). Redundancy analysis demonstrated that the pH and microbial functional metabolism were closely related to carbon sequestration during composting.

Metabolic function, trophic mode, organics degradation ability and influence factor of bacterial and fungal communities in chicken manure composting

The metabolic function and organic degradation behavior of bacterial and fungal communities were detected in 60 days composting of chicken manure and pumice by using Biolog tools, PICRUSt and FUNGuild. Fungal diversity increased from 57 OTUs in fresh chicken manure to 109 OTUs in high temperature stage, while bacterial diversity decreased from 86 OTUs to 44 OTUs after composting treatment. The carbohydrates degradation ability of bacterial community was enhanced in the high temperature stage. Fungal community had relatively higher degradation rates of carboxylic acids and amino acids in the maturation stage. Saprotroph was the main trophic mode of fungal community during the incubation process. The fungal animal pathogen decreased from 12.5% to 1.2% after composting treatment. Bacterial community composition and substrates degradation rate were mainly influenced by redox potential, pH and moisture, while temperature was the main environmental factor influencing on organic degradation of fungal community.

Effect of bean dregs amendment on the organic matter degradation, humification, maturity and stability of pig manure composting

The purpose of this study was to effectively dispose of bean dregs (BD) using composting technology, which could provide a theoretical basis for the disposal of BD. Therefore, the influence of different quantities of bean dregs (BD) (0%, 5%, 10% and 15%, w/w with a dry base of pig manure (PM)) on the decomposition and humification of organic matter during PM-composting was investigated, and a 0% BD amendment was used as the control (CK). Wheat straw was used as a bulking agent. Compared to the CK, the BD amendment promoted the degradation of organic matter. The degree of organic matter degradation increased by 16.46-25.04% upon BD amendment. Furthermore, the BD amendment improved humification and increased indices of the humification ratio (HR), percentage of humic acids (PHA), degree of polymerization (DP) and the humification index (HI). Furthermore, Fourier transform infrared (FTIR) spectroscopy indicated that the aromatic structure was enhanced with the BD amendment, and excitation-emission matrix (EEM) fluorescence spectra showed increased humic-like substance production. Additionally, the dissolved organic carbon (DOC), germination index (GI), electrical conductivity (Ec) and carbon/nitrogen (C/N) influenced the maturity and stability of composting. Comparatively, a 10% BD addition showed the optimal performance among all PM-composting treatments.

Insight into the cadmium and zinc binding potential of humic acids derived from composts by EEM spectra combined with PARAFAC analysis

To investigate the characteristics of humic acids (HAs) and the combined effects of HAs on heavy metals, three HAs derived from kitchen waste compost (KW), pig manure compost (PM), and green waste compost (GW) were exposed to Cd(II) and Zn(II). The elemental contents and functional groups of HAs were different due to different raw materials. Fulvic-, humic-like content C1, humic-like content C4, and two protein-like contents C2 and C3 were identified in three HAs by EEM-PARAFAC analysis. The effects of HAs on heavy metals were associated with the metal species and HA source. Our results reveal that titrating Cd(II) caused stronger fluorescence quenching compared to titrating Zn(II) for all HAs. C1 and C4 of KW-HAs and PM-HAs showed fluorescence quenching after Cd(II) was added, whereas negligible fluorescence quenching was found when Zn(II) was added. In addition, C1 and C4 in the GW-HAs did not show obvious fluorescence quenching regardless of whether Cd(II) or Zn(II) was added. C3 in all HAs caused significant fluorescence quenching, suggesting that C3 plays an important role affecting the mobility of heavy metals. Consequently, these results suggest that HAs from KW and PM have greater potential for Cd-contaminated soil remediation than those from GW.

Effect of manganese dioxide on the formation of humin during different agricultural organic wastes compostable environments: It is meaningful carbon sequestration

The study aims to accelerate the formation of humin (HM) with the addition MnO₂ to achieve carbon sequestration during different material composting. The results indicated that the addition of MnO₂ could improve the concentration of HM by increasing of the content in functional groups during corn straw (CS) and chicken manure (CM) composting. With the addition of MnO₂, non-aromatic functional groups were responsible for the increase of the HM concentration in CM, while aromatic functional groups were dominating for CS. Although the formation mechanism of HM varied significantly across different materials, the MnO₂ promoted more abundant functional groups to participate the formation of recalcitrant fluorescence components in CS and CM. In addition, the aromatization of HM structure was improved by adding the MnO₂. Therefore, the addition of MnO₂ not only increase carbon sequestration but also increase the compost product resilience during the decompose of agricultural organic wastes.

Responses of microbial communities to a gradient of pig manure amendment in red paddy soils

Microbial communities play a key role in maintaining agroecosystem functioning and sustainability, but their response to excessive animal manure application and relevant mechanisms have not been thoroughly elucidated to date. This study investigated the responses of soil bacterial and fungal communities to pig manure (PM) amendment in red paddy soils. High-throughput sequencing revealed that PM amendment significantly reduced the relative abundance of Acidobacteria yet increased that of Bacteroidetes, Ignavibacteriae, Firmicutes, and Rozellomycota. The Cu and available phosphorus were the primary impact factors influencing bacterial and fungal diversity, respectively. Bacterial alpha-diversity tended to sharply decrease when the content of soil Cu was >30.70 mg kg^-1, while fungal alpha-diversity did not continuously increase when the content of soil available phosphorus was >82.84 mg kg^-1. Bacterial communities with a wider niche breadth showed significantly lower structural variation, whereas fungal communities with a narrower niche breadth showed greater variation in community structure. Soil heavy metals, primarily Cu and Zn, were the primary factors that affected bacterial communities, whereas soil fungal communities were mainly influenced by soil phosphorus. Bacterial and fungal communities showed distinct co-occurrence patterns, with bacterial communities showing a higher degree, a clustering coefficient, and betweenness centrality, but a lower closeness centrality. The findings highlighted that bacteria and fungi responded differently to PM amendment because of their discrepant niche breadth, interspecific relationships, and different tolerance to heavy metal and soil nutrient.

Impact of pine leaf biochar amendment on bacterial dynamics and correlation of environmental factors during pig manure composting

The influence of pine leaf biochar (PLB) amendment on bacterial community succession and its correlation with physic-chemical parameters during pig manure (PM) composting was evaluated. The five different dosages of PLB [at 0% (T1), 2.5% (T2), 5% (T3), 10% (T4) and 15% (T5)] mixed with initial composting mass were conducted to composting for 50 days. The present study indicated that bacterial diversity was significantly (p < 0.05) higher in PLB amended treatments than the control, but T4 treatment showed the highest among the all PLB applied treatment. Firmicutes, Actinobacteria, Proteobacteria and Bacteroidete were four most abundant phyla of all the treatments. Furthermore, redundancy analysis showed that the bacterial community were significantly (p < 0.05) positively correlated with temperature, pH, TOC, CO₂ and NH₃ emissions, while they were negatively correlated with the N₂O and CH₄ emission. Overall, the results suggested that the addition of 10% PLB (T4 treatment) was a potential option to enhance the composting efficiency with significantly greater abundance of bacterial community and finally improved the compost quality.

Spectroscopic evidence for hyperthermophilic pretreatment intensifying humification during pig manure and rice straw composting

Hyperthermophilic pretreatment composting (HPC) is superior to traditional composting (CK) with shortened maturity period and enhanced humification degree. However, the chemical and structural evolution of humic substances (HS) at the molecular level is not known. In this study, the impact of hyperthermophilic pretreatment (90 °C, 4 h) on the content and chemical composition of HS during composting were investigated. The HS content of the final compost was 87.8 g/kg and 76.7 g/kg in HPC and CK, respectively. Significantly higher humic acid/fulvic acid ratio (1.27 in HPC v.s. 0.77 in CK) was observed in HPC. ¹³C NMR spectroscopic data showed a higher aromatics percentage and earlier enrichment of aromatic structures in HS extracted from HPC than CK. Intensified humification of HPC was related to the increased levels of HS precursors and degradation of lignocellulose. Redundancy analysis demonstrated that aromatic C, phenolic C and O-alkyl C can be used for evaluation of the humification degree.

Performance of black soldier fly larvae (Diptera: Stratiomyidae) for manure composting and production of cleaner compost

The increasing number of livestock farms has led to a great deal of manure generation, and its improper treatment results in threats to the environment. Black soldier fly larvae (BSFL) have the potential to effectively convert manure into high-quality fertilizer. The aims of this investigation were to observe the organic matter transformation of different livestock manures and volatile fatty acids (VFAs), and to evaluate the end product quality. Three types of manure [chicken (T1), pig (T2), and cow (T3)] were inoculated with BSFL (1.2:7 ratio on fresh weight basis), three types without BSFL were used as control (T4, T5, and T6), and both were composted for 9 days. The results showed that the BSFL composting reduced the organic matter by 20.31-22.18% and the accumulation of VFAs by 25.58-80.08% as compared to the control. BSFL composting greatly decreased the nitrogen, by 6.08-14.37%. The employment of BSFL significantly increased the total phosphorous (TP), total Kjeldahl nitrogen (TKN), and total nutrients by 42.30-64.16%, 45.41-88.17%, and 26.51-33.34%, respectively. This study showed that employing BSFL could improve the quality of the product and the maturity degree of the composting. Therefore, the BSFL could be added as a high-efficiency transformation agent for converting organic manure into stable compost, especially in developing countries, where adopting technical devices for composting is expensive and difficult to manipulate.

Enhanced humification of maize straw and canola residue during composting by inoculating Phanerochaete chrysosporium in the cooling period

To enhance the humification process, Phanerochaete chrysosporium (P. chrysosporium) was inoculated during different fermentation phases of the co-composting of maize straw and canola residue. The humification process was determined by evaluating cellulose and lignin contents and key enzyme activities during composting. Results showed that the cellulose and lignin degradation efficiency and humification degree of compost were significantly enhanced in the treatment that inoculated P. chrysosporium in the cooling period (T2). At the end of composting, compared with that in T1 (no inoculation), the content of cellulose and lignin in T2 decreased significantly by 40.00% and 64.30%, respectively, and compared with that in T1 and T3 (inoculation in the initial stage of composting) the content of humus in T2 increased significantly by 55.40% and 75.20%, respectively. This study confirms that inoculating P. chrysosporium during the cooling period promoted the degradation of cellulose and lignin, and therefore enhanced the compost humification.

Recognition of the neutral sugars conversion induced by bacterial community during lignocellulose wastes composting

The aim of this study was to explore the conversion characteristics of neutral sugars during different lignocellulose wastes composting from rice straw (RS), leaf (L) and mushroom dreg (MD). The results showed that the changes of neutral sugars were different during different wastes composting, but the changes of various hexose or pentose were similar during composting of the same material. The diversity of bacterial community led to different conversion characteristics of neutral sugars. During RS composting, each neutral sugar was transformed by a specific group of bacteria. However, a group of bacteria could transform multiple neutral sugars during MD and L composting. Furthermore, GM/AX value was first applied to composting, which could be used to characterize the conversion of neutral sugars during composting. This will help to provide more efficient recommendations for lignocellulose wastes treatment and accelerating humic substances synthesis during composting.

Improved lignocellulose degradation efficiency based on Fenton pretreatment during rice straw composting

This study aims to explore the effect of Fenton pretreatment on organic fractions, enzymes activities and microbial communities during composting. In this study, rice straw was chosen to be composted after pretreatment. The results indicated that Fenton pretreatment significantly increased the degradation of organic matter and coarse fiber contents, which might be the reason that Fenton pretreatment enhanced lignocellulose-degrading enzymes activities during composting, including CMCase, FPase, xylanase, manganese peroxidase, lignin peroxidase and laccase. Additionally, Fenton pretreatment reshaped bacteria community. The key enzymes and environmental factors, which affected organic fractions degradation were identified by redundancy analysis. Furthermore, structural equation modeling and variation partitioning analysis further revealed possible mechanisms of organic fractions degradation in different treatments during composting. In summary, the combined application Fenton pretreatment and composting improved lignocellulose degradation efficiency, which provided for an effective and environment-friendly way to manage lignocellulose wastes.

Effects of four additives in pig manure composting on greenhouse gas emission reduction and bacterial community change

Four different additives of Medical stone (MS), Zeolite (ZL), Bamboo biochar (BC), and Wood vinegar (WV) were investigated in pig manure composting. The four additives reduced the peak CH₄ emission from 54% to 74%, while reduced N₂O loss from 36% to 69%, compared with control (CK). WV and ZL showed better ability in N₂O loss reduction, yet MS with the efficient inhibition both on CH₄ and NH₃ emissions. The bacterial community analysis indicated that bacterial diversity in the maturity phase was higher than that in the thermophilic phase, especially with treatments of ZL, BC and WV. The selected factors of pH, temperature, TOC and DOC could influence the thermophilic phase, while EC and TKN related closely with maturity phase in pig manure composting.

Organic matter, a critical factor to immobilize phosphorus, copper, and zinc during composting under various initial C/N ratios

The status of heavy metals and the P fractions in compost affects their environmental risk. The present study investigated the effects of different initial carbon to nitrogen (C/N) ratios (15, 22, 27) on redistribution of Cu, Zn, and P fractions during composting. The results showed that the composting process transformed Cu, Zn and P from mobile fractions to more stable fractions. Compost with an initial C/N of 22 showed the most effective immobilization of Cu, Zn and P because of yielding greatest degree of polymerization. Multivariate statistical analysis identified organic matter as the most critical factor for explaining the redistribution of Cu, Zn, and P fractions in composting. However, the degree of organic matter degradation (organic matter content and Humic acid/Fulvic acid) better explained the change of bioavailability factor for Cu and the mobility of P during composting. This research provided guidance for providing technology to reduce environmental risk in compost.

Effects of bulking material types on water consumption and pollutant degradation in composting process with controlled addition of different liquid manures

This study was conducted to examine the effects of different bulking materials (corncob and ricehusk) on liquid manure consumption, organic matter degradation and pollutants retention in composting process under controlled addition of different types of liquid manures (LM). The results indicated that under the controlled addition of LM, bulking materials with higher content of biodegradable carbon (corncob) and LM with a higher concentration of organic pollutants (swine effluent) were more beneficial for biological heat generation and thus were more efficient for water evaporation, organic matter degradation, LM consumption and pollutants retention during the cocomposting process. Consequently, the optimization of these major influencing factors could compensate for efforts geared towards better utilization of the cocomposting process.

Effects of compost characteristics on nutrient retention and simultaneous pollutant immobilization and degradation during co-composting process

This study was conducted to examine the effects of controlled addition of liquid (LM) to solid (SM) manure compost using a volume-model technique on the co-composting of SM and LM, and further to investigate the major effects of bulking material sizes and LM types on the co-composting process and final compost characteristics. Results indicated that this volume-model technique played a critical role in reducing leachate generation and improving the overall efficiency of the co-composting process. Specifically, the developed model enhanced the evaporation rates of windrows during the co-composting process. For improved final compost properties, small bulking materials and swine-effluent-based LM were found to be more efficient for organic matter degradation, LM consumption, hazardous metals immobilization, and essential nutrients retention than large bulking materials and biogas-based LM. Thus, process parameter optimizations represent major research options for successful co-composting applications for the future.

Succession of organics metabolic function of bacterial community in swine manure composting

Organics metabolic function of bacterial communities was evaluated in 60 days composting of swine manure and pumice by using MiSeq sequencing, PICRUSt and Biolog tools. The diversity of bacterial communities significantly decreased during the first 10 days, and gradually increased in the cooling and curing phase. The PICRUSt and Biolog analysis indicated that carbohydrate, lipid and amino acids metabolisms were relatively higher in the thermophilic phases. Xenobiotics biodegradation and metabolism, lipid metabolism, terpenoids and polyketides and biosynthesis of other secondary metabolites were mainly detected in the curing phases. Canonical correspondence analysis (CCA) indicated that the succession of bacterial community and organics utilization characteristics were highly affected by the temperature, moisture and oxidation reduction potential (ORP) in the swine composting system.

Feasibility of medical stone amendment for sewage sludge co-composting and production of nutrient-rich compost

The feasibility of medical stone (MS) amendment as an innovative additive for dewatered fresh sewage sludge (DFSS) co-composting was assessed using a 130-L vessel-scale composter. To verify successful composting, five treatments were designed with four different dosages (2, 4, 6, and 10) % of MS with a 1:1 mixture (dry weight) of DFSS + wheat straw (WS). The WS was used as a bulking agent. A control without any amendment treatment was carried out for the purpose of comparison. For DFSS co-composting, the amendment with MS improved the mineralization efficiency and compost quality in terms of CO₂ emissions, dehydrogenase enzyme (DE), electrical conductivity (EC), water-solubility, and total nutrients transformation. The DTPA-extractable Cu and Zn were also estimated to confirm the immobilization ability of the applied MS. Seed germination and plant growth tests were conducted to ensure the compost stability and phytotoxicity for Chinese cabbage (Brassica rapa chinensis L.) growth and biomass, as well as chlorophyll content. The results showed that during the bio-oxidative phase, DOC, DON, AP, NH₄⁺-N, and NO₃^--N increased drastically in all the MS-blended treatments, except the application of 2% MS and the control treatment; significantly lower water-soluble nutrients were observed in the 2% MS and control treatments. A novel additive with 6-10% MS dosages considerably enhanced the organic matter conversion in the stable end-product (compost) and reduced the maturity period by two weeks compared to the 2% MS and control treatments. Consequently, the maturity parameters (e.g., EC, SGI, NH₄⁺-N, DOC, and DON) confirmed that compost with 6-10% MS became more stable and mature within four weeks of DFSS co-composting. At the end of composting, significantly higher DTPA-extractable Cu and Zn contents were observed in the control treatment, and subsequently, in the very low application (10%) of MS. Higher MS dosage lowered the pH and EC to within the permissible limit compared to the control, while increased concentrations of water-soluble nutrients diminished the DTPA-extractable Cu and Zn contents. In addition, plant growth experiments demonstrated that the addition of compost with 150 kg ha^-1 TKN improved the Chinese cabbage biomass and chlorophyll level. The highest dry weight biomass (2.78 ± 0.02 g/pot) was obtained with 6% MS-blended compost while the maximum chlorophyll content was found with application of 4% MS compost (41.84 SPAD-unit) for Chinese cabbage. Therefore, 6-10% MS can be recommended to improve DFSS composting and to reduce the period to maturity by two weeks when considering its composting effect on Chinese cabbage growth, biomass yield, and chlorophyll level. However, amendment with 6% MS is a more economically feasible approach for DFSS co-composting.

Comparison of biochar, zeolite and their mixture amendment for aiding organic matter transformation and nitrogen conservation during pig manure composting

The aim of this work was to compare the impact of biochar, zeolite and their mixture on nitrogen conservation and organic matter transformation during pig manure (PM) composting. Four treatments were set-up from PM mixed with wheat straw and then applied 10% biochar (B), 10% zeolite (Z) and 10% biochar+10% zeolite (B+Z) into composting mixtures (dry weight basis), while treatment without additives applied used as control. Results indicated that adding B, Z and B+Z could obviously (p<0.05) improve the organic matter degradation and decrease the nitrogen loss. And combined addition of B and Z further promoted the organic matter humification and reduced the heavy metals mobility. Meanwhile the highest mitigation of ammonia (63.40%) and nitrogen dioxide (78.13%) emissions was observed in B+Z added treatment. Comparison of organic matter transformation, nitrogen conservation and compost quality indicated that the combined use of biochar and zeolite could be more useful for PM composting.