Mixed Compost Research Articles

Microbial electrochemical enhanced composting of sludge and kitchen waste: Electricity generation, composting efficiency and health risk assessment for land use

To realize the energy and resource utilization from organic solid waste, a two-phase microbial desalination cell (TPMDC) was constructed using dewatered sludge and kitchen waste as the anode substrate. The performance of electricity generation and composting efficacy was investigated, along with a comprehensive assessment of the potential health risks associated with the land use of the resulting mixed compost products. Experimental outcomes revealed a maximum open-circuit voltage of 0.893 ± 0.005 V and a maximum volumetric power density of 0.797 ± 0.009 W/m³. After 90 days of composting enhanced by microbial electrochemistry, a significant organic matter removal rate of 31.13 ± 0.44 % was obtained, and the anode substrate electric conductivity was reduced by 30.02 ± 0.04 % based on the anode desalination. Simultaneously, there was an increase in the content of available nitrogen, phosphorus, and potassium, as well as an improvement in the seed germination index. The forms of heavy metals shifted from bioavailable to stable residual states. The non-carcinogenic hazard index (HI) values for heavy metals and polycyclic aromatic hydrocarbons (PAHs) during the land use of compost products were less than 1, and the total carcinogenic risk (TCR) values for heavy metals and PAHs were below the acceptable threshold of 10−4. The occupational population risk of infection from five pathogens was higher than that of the general public, with all risk values ranging from 8.67 × 10−8 to 1, where the highest risk was attributed to occupational exposure to Legionella. These outcomes demonstrated that the mixture of dewatered sludge and kitchen waste was an appropriate anode substrate to enhance TPMDC stability for electricity generation, and its compost products have promising land use suitability and acceptable land use risk, which will provide important guidance for the safe treatment and disposal of organic solid waste.

Pengaruh Pemberian Kompos Campuran Ampas Tebu dan Kotoran Ayam terhadap Kesuburan Ultisol dan Hasil Produksi Kedelai (Glycine max (L.) merril)

Ultisol is a soil that contains low nutrients N, P and K and has the potential for Al-poisoning. Ultisol also has a low Cation Exchange Capacity, acidic soil pH and is sensitive to erosion. Improvements need to be made to increase Ultisol productivity, one of which is by adding organic ingredients. In addition to sugarcane bagasse compost, chicken manure contains many benefits because it contains a lot of organic materials that are good for the soil and plants. Increasing soybean yield is one of the priorities and can be done by utilizing Ultisol land. The purpose of this study is to determine the effect of composting a mixture of bagasse and chicken manure on ultisol fertility and soybean crop production. The research method carried out is experimental by conducting initial analysis of soil samples, compost application, maintenance, harvesting, soil analysis after compost application, calculation of height and crop yield. The results obtained were that the application of mixed compost of bagasse and chicken manure did not have a real effect on soil pH, P-available and Aldd, but could increase soil pH and P-available and lower Aldd in the soil. The application of mixed compost of bagasse and chicken manure was significantly different from plant height and was very different for soybean yield with the highest crop P3 (average plant height of 84.678 cm) and the highest yield of P3 3.938 tons/ha. The recommended treatment for soybean plants is P3 treatment with a dose of 15 tons/ha.

Research on the Composting Technology of Cattle and Sheep Manure Based on Intelligent and Efficient Composting Equipment and the Evaluation Standard of Decomposition Degree

The Inner Mongolia Autonomous Region is a crucial area in China with a significant advantage in animal husbandry, particularly in cattle and sheep farming. However, the disposal of the large quantities of manure produced during farming has severely impacted the industry’s healthy development. Proper treatment of the manure can convert it into organic fertilizer beneficial to farmland; otherwise, it will cause substantial environmental pollution. This study focuses on existing composting equipment and addresses the issues of cattle and sheep manure mixture ratios and compost maturity evaluation. Through experiments on the mixture of cattle and sheep manure, the optimal ratio for converting cattle and sheep manure into organic fertilizer was determined. Additionally, a fuzzy mathematical evaluation model was employed, along with experimental data, to establish a comprehensive evaluation system for aerobic compost maturity based on multiple indicators, revealing the variation patterns of maturity levels under different mixture ratios. The test results revealed that the composting equipment effectively controls the composting process, shortens the composting cycle, ensures the complete decomposition of organic matter, and meets national standards for livestock and poultry manure treatment. Regarding temperature and humidity, oxygen concentration, seed germination rate, pH value, electrical conductivity (EC), nitrogen, phosphorus, potassium content, and carbon-to-nitrogen ratio, the mixed compost of cattle and sheep manure in various ratios met the relevant standards for agricultural application. Various ratios of organic fertilizers containing cattle and sheep manure significantly promoted the growth of maize, wheat, and mung bean crops. Specifically, the compost decomposition cycle was shortest when sheep and cattle dung were mixed at a ratio of 2:1, while it was longest for all cattle dung. Finally, a fuzzy mathematical comprehensive evaluation model was established by selecting four indicators: water content, carbon-to-nitrogen ratio, apparent score, and germination index. The study demonstrates that the equipment and method offer significant advantages in efficiently treating cattle and sheep manure and producing organic fertilizer, thereby providing strong support for the sustainable development of animal husbandry.

The Impacts of the C/N Ratio on Hydrogen Sulfide Emission and Microbial Community Characteristics during Chicken Manure Composting with Wheat Straw

Wheat straw (WS) has long been subjected to rough treatment by traditional incineration, which not only results in the waste of biomass resources but also poses a risk of atmospheric pollution and is not conducive to the sustainable utilization of natural resources. With great humification potential, WS can be utilized as a valuable composting material. The study optimized the C/N ratio by mixing WS and chicken manure (CM) as composting raw materials, and found that this method could significantly improve the compost quality. In comparison to the conventional poplar woodchip (PW) conditioning, the incorporation of WS resulted in an elevated composting temperature, an extended high-temperature period, a more expeditious lignocellulose degradation, a notable enhancement in the organic matter content, a suppression of hydrogen sulfide production under low C/N ratio, and a promotion of elemental sulfur conversion, collectively contributing to an enhanced overall quality and environmental friendliness of the compost. Correlation analysis of microbial communities and environmental factors demonstrated that the mixed compost facilitated the growth of actinomycetes and sulfur-transforming bacteria. Additionally, structural equation model indicated that parameters such as temperature and pH value played a key role in the composting process.

Optimizing wheat productivity through integrated management of irrigation, nutrition, and organic amendments

Enhancing wheat productivity by implementing a comprehensive approach that combines irrigation, nutrition, and organic amendments shows potential for collectively enhancing crop performance. This study examined the individual and combined effects of using irrigation systems (IS), foliar potassium bicarbonate (PBR) application, and compost application methods (CM) on nine traits related to the growth, physiology, and yield of the Giza-171 wheat cultivar. Analysis of variance revealed significant (P ≤ 0.05) main effects of IS, PBR, and CM on wheat growth, physiology, and yield traits over the two growing seasons of the study. Drip irrigation resulted in a 16% increase in plant height, leaf area index, crop growth rate, yield components, and grain yield compared to spray irrigation. Additionally, the application of foliar PBR at a concentration of 0.08 g/L boosted these parameters by up to 22% compared to the control. Furthermore, the application of compost using the role method resulted in enhanced wheat performance compared to the treatment including mix application. Importantly, the combined analysis revealed that the three-way interaction between the three factors had a significant effect (P ≤ 0.05) on all the studied traits, with drip irrigation at 0.08 g PBR rate and role compost application method (referred as Drip_0.08g_Role) resulting in the best performance across all traits, while sprinkle irrigation without PBR and conventional mixed compost method (referred as sprinkle_CK_Mix) produced the poorest results. This highlights the potential to synergistically improve wheat performance through optimized agronomic inputs.

The Impact of Food Waste Compost, Vermicompost, and Chemical Fertilizers on the Growth Measurement of Red Radish (Raphanus sativus): A Sustainability Perspective in the United Arab Emirates.

The pressing need for sustainable agricultural practices, especially with the increasing population, has directed attention towards alternative fertilizers that enhance crop yield while preserving soil integrity and reducing food loss. The current study investigated the comparative efficacy of food waste compost (FOWC), vermicompost, and chemical fertilizers on the growth of red radish. The present work used a systematic experimental design to evaluate plant growth parameters, including radish weight and height. The soil quality was determined by measuring the pH and electrical conductivity for all soil samples. The results indicated a significant variation in red radish fresh weight among different treatments. For example, the 25% vegetable and fruit waste compost (VFWC) treatment demonstrated a relatively high mean fresh weight, while the 50% mixed compost (MC) treatment yielded a much lower mean fresh weight. These numbers underscore the potential efficacy of specific food waste treatments in enhancing plant growth, with vermicompost at 50% and VFWC at 25% showing considerable promise in increasing crop yield. The current study concluded that FOWC and vermicompost significantly improved plant growth, advocating for their use as sustainable and environmentally friendly alternatives to chemical fertilizers. The current findings emphasized the importance of selecting appropriate fertilizer types and concentrations to optimize agricultural productivity and environmental sustainability, supporting the incorporation of food waste into agricultural systems as a beneficial resource.

Combined Aerobic Fermentation of Maricultural and Agricultural Solid Waste: Physicochemical Property and Bacterial Community Structure

The large-scale production of maricultural solid waste is not used effectively and has a significant impact on the environment. However, there is no report on the utilization of solid waste in mariculture of maricultural and agricultural solid waste. At present, aerobic composting is a simple and feasible means of waste resource utilization, but it also seriously pollutes the environment. This paper studied the change of physical and chemical properties (T1: solid waste + straw, T2: solid waste + cow dung + straw, T3: solid waste + cow dung + straw + 5% biochar, T4: solid waste + chicken dung + cow dung + straw + 5% biochar) and microbial succession in the composting process (T4: solid waste + chicken dung + cow dung + straw + 5% biochar) and the effect of decomposed products on seed growth. The results showed that the mixed compost of various materials had a good regulating effect on the physical and chemical indexes, and the highest temperature could reach 69.4 °C. Biochar could extend the high temperature period by 1–2 days. The germination indexes of seeds treated with T1–T4 were 75%, 80%, 81%, and 94%, respectively. Through the change of the seed germination index, it could be seen that the bacterial community structure changed significantly during composting. The Chao 1 index and Shannon index showed that the bacterial abundance and diversity index increased and then decreased. The analysis of the bacterial community structure showed that Proteobacteria and Acinetobacter were the main bacteria in composting, and the relative abundance of Proteobacteria was 81.9% at the phyla level. Acinetobacter and Pseudoxanthomonas were the main bacteria in the process of composting. Acinetobacter was the dominant bacteria in the heating stage, with an abundance of 67.2%.

Effects of adding exogenous microorganisms on nitrogen conversion and its mechanism of action in pig carcass composting

This study aimed to reveal mechanisms of nitrogen changes in a mixed compost of diseased pig carcasses and sawdust after adding exogenous microbial agents. It was found that adding exogenous microbial agents significantly increased the content of various types of nitrogen and the germination index of plants. Microbial dominance of phyla was significantly correlated with indicators of physicochemical properties and copy number of nitrogen-functional genes, with simultaneous nitrogen fixation, nitrification, denitrification, ammonification, and glutamate synthesis during composting. At the end of composting, TKN, NH4+-N, and NO3−-N contents were increased by 1.914–3.082 mg/g, 0.047–0.42 mg/g, and 0.247–0.303 mg/g, respectively, in the experimental groups compared to the control group. Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, and Planctomycetes were the five predominant phyla, while Sphingobacterium, and Paenalcaligenes were the two special genera in this experiment. After inoculation with exogenous microbial agents, the levels of nitrate nitrogen were significantly and positively correlated (p < 0.05) with the number of Bacteroidetes, the glnA gene was positively related (p < 0.01) with Planctomycetes, and the amoA, GDH2, and GLUD1-2 genes were positively related (p < 0.05) with Paenalcaligenes. The combined analysis has shown that amoA gene was positively related (p < 0.001) with genes such as nxrA, GDH2 and GLUD1-2, as well as indicators of physicochemical properties such as temperature, organic nitrogen and nitrate nitrogen, while the correlation was negative with genes such as nirB and nirS. Inoculation with exogenous microbial agents can significantly prolong the high-temperature period, which was extended by 5, 6, and 5 days in each experimental group, and the roles of nitrogen-functional genes can also be changed. Meanwhile, we found that the addition of exogenous microbial agents could promote the growth and alteration of microorganisms, which regulated the stability and symbiosis of the nitrogen transformation process.

Maximising carbon sequestration through mixing compost in moist soil

Organic amendments to soil often enhance soil organic matter (SOM) decomposition, also referred to as a priming effect (PE). However, decomposition of the organic amendment itself could also be altered when mixed in soil, with important consequences for the net soil carbon (C) balance and nutrient cycling, but this has rarely been explored. We examined decomposition and gross nitrogen (N) mineralisation of compost (C:N = 29) and SOM (C:N = 12) separately and when mixed, at two different moisture levels (45 and 85% water holding capacity) in a 42-day laboratory incubation study. As observed by many others, compost addition enhanced decomposition of SOM (i.e., causing a PE) at both moisture levels. In contrast, decomposition of compost was strongly reduced when mixed with soil, particularly at the highest moisture level, which more than compensated for the PE. These results indicate that the microbial decomposer community had a greater preference for decomposing SOM than decomposing compost when mixed, possibly because decomposition of SOM released more N than decomposition of compost in meeting the microbial demand for N. This was supported by higher gross N mineralisation rates at the end of the incubation period in compost-soil mixtures compared to what would be expected from gross N mineralisation rates in their separate components. It is also possible that mineral adsorption of organic compounds derived from compost caused greater protection against microbial decomposition of compost, and thus reduced compost decomposition when mixed into soil. We conclude that mixing compost in soil could result in greater net soil C gains compared to having compost and soil separate, particularly under moist conditions.

THE YIELD OF ANJASMORO CULTIVARS SOYBEAN [Glycine max (L.) Merrill] WITH COMPOST TREATMENT FROM TOBACCO OR SOURSOP LEAVES AND ITS WEED CONDITIONS

One of the important problems in soybean production is the weed growth. This study was conducted to observe the growth of weeds in the growth of soybean plants that are given compost. Anjasmoro soybean varieties were planted in Surakarta, on April 14, 2020. There are four types of treatment, namely given compost fertilizer made from tobacco leaves, soursop leaves, a mixture of tobacco leaves and soursop, and without fertilizer. Weeds were allowed to grow together with soybeans in 15 polybags, per treatment. Observation and identification of weeds were carried out twice, 4 weeks after planting and at harvest time. The results found 9 kinds of weeds consisting of 5 species of Monocots and 4 types of Dicotiles. The total wet weight of weeds was every treatment: 1,539 grams, while the wet weight of the soybean crop at harvest was 858.4 grams. Wet weed weight in the control treatment was 284,8 grams. The wet weight of weeds in soybean plants was the largest mixture fertilizer treatment that is 514,8 grams. The number of pods ranges from 17 to 26. The sum of seeds per soybean plant in giving mixed compost is at most 98 grains. Mixed fertilizer treatment can increase the yield of Anjasmoro soybean, although weed growth up.

Do drinking water treatment residuals underperform in the presence of compost in stormwater media filters?

Drinking water treatment residuals (WTR), a waste-derived product, are often recommended to use as an amendment in stormwater biofilters to enhance their capacity to remove phosphate and microbial pollutants. However, their efficacy has been assumed to remain high in the presence of compost, one of the most common amendments used in biofilters. This study tests the validity of that assumption by comparing the removal capacities of WTR-amended biofilters with and without the presence of compost. Our results show that amending sand with WTR increased E. coli removal by at least 1-log, but the addition of compost in the sand-WTR media lowered the removal capacity by 13 %. Similarly, the addition of WTR to sand improved phosphate removal to nearly 1177 %, but the removal decreased slightly by 8 % when adding compost to the media. The results confirmed that dissolved organic carbon (DOC) leached from the compost could compete for adsorption sites for bacteria and phosphate, thereby lowering WTR's adsorption capacity based on the amount of DOC adsorbed on WTR. Collectively, these results indicate that the stormwater treatment industry should avoid mixing compost with WTR to get the maximum benefits of WTR for bacterial removal and improve the performance lifetime of WTR-amended biofilters.

Analysis of The Physical Quality of Coffee Husk Compost with The Addition of EM4 Bioactivator

Coffee production potential is matched by waste from grinding coffee cherries. However, the coffee cherry peel (husk) is rich in essential nutrients for plant growth, including potassium, phosphorus, and nitrogen. Therefore, the purpose of this research was conducted to determine the physical quality of coffee husk compost given the addition of EM4 bioactivator. This study consisted of 2 treatments and 4 replications, namely control (coffee husk + sawdust + goat manure) and EM4 (coffee husk + sawdust + goat manure + EM4). Observations were made every 3 days until the compost was ripe with the parameters of temperature, humidity, color, smell, and texture. The results showed that the entire coffee husk compost had matured within 36 days and exhibited physical characteristics according to SNI 19-7030-2004. According to the matured compost speed, treatment with mixing compost materials using EM4 shows a faster time than without EM4. In addition, the addition of EM4 gives better results in terms of texture, color, and smell compared to compost without EM4

Evolution of fungal and non-fungal eukaryotic communities in response to thermophilic co-composting of various nitrogen-rich green feedstocks.

Thermophilic composting is a promising soil and waste management approach involving diverse micro and macro-organisms, including eukaryotes. Due to sub-optimal amounts of nutrients in manure, supplemental feedstock materials such as Lantana camara, and Tithonia diversifolia twigs are used in composting. These materials have, however, been reported to have antimicrobial activity in in-vitro experiments. Furthermore, the phytochemical analysis has shown differences in their complexities, thus possibly requiring various periods to break down. Therefore, it is necessary to understand these materials' influence on the biological and physical-chemical stability of compost. Most compost microbiome studies have been bacterial-centric, leaving out eukaryotes despite their critical role in the environment. Here, the influence of different green feedstock on the fungal and non-fungal eukaryotic community structure in a thermophilic compost environment was examined. Total community fungal and non-fungal eukaryotic DNA was recovered from triplicate compost samples of four experimental regimes. Sequencing for fungal ITS and non-fungal eukaryotes; 18S rDNA was done under the Illumina Miseq platform, and bioinformatics analysis was done using Divisive Amplicon Denoising Algorithm version 2 workflow in R version 4.1. Samples of mixed compost and composting day 84 recorded significantly (P<0.05) higher overall fungal populations, while Lantana-based compost and composting day 84 revealed the highest fungal community diversity. Non-fungal eukaryotic richness was significantly (P< 0.05) more abundant in Tithonia-based compost and composting day 21. The most diverse non-fungal eukaryotic biome was in the Tithonia-based compost and composting day 84. Sordariomycetes and Holozoa were the most contributors to the fungal and non-fungal community interactions in the compost environment, respectively. The findings of this study unravel the inherent influence of diverse composting materials and days on the eukaryotic community structure and compost's biological and chemical stability.

Transmission and retention of antibiotic resistance genes (ARGs) in chicken and sheep manure composting

Transmission of ARGs during composting with different feedstocks (i.e., sheep manure (SM), chicken manure (CM) and mixed manure (MM, SM:CM = 3:1 ratio) was studied by metagenomic sequencing. 53 subtypes of ARGs for 22 types of antibiotics were identified as commonly present in these compost mixes; among them, CM had higher abundance of ARGs, 1.69 times than that in SM, while the whole elimination rate of CM, MM and SM were 55.2%, 54.7% and 42.9%, respectively. More than 50 subtypes of ARGs (with 8.6%, 11.4% and 20.9% abundance in the initial stage in CM, MM and SM composting) were “diehard” ARGs, and their abundance grew significantly to 56.5%, 63.2% and 69.9% at the mature stage. These “diehard” ARGs were transferred from initial hosts of pathogenic and/or probiotic bacteria to final hosts of thermophilic bacteria, by horizontal gene transfer (HGT) via mobile gene elements (MGEs), and became rooted in composting products.

Novel soil-less potting mixes for the mycorrhization of Quercus pubescens Willd. seedlings with Tuber melanosporum Vittad.

Truffle cultivation has quickly grown in Europe and elsewhere as a consequence of the increase in the demand of the market. Thus the optimization of the protocols for the production of elite mycorrhized plants are also needed, keeping in consideration the economic and environmental sustainability. The suitability of two compost-based potting mixes to produce Quercus pubescens Willd. plants mycorrhized with the black Périgord truffle T. melanosporum Vittad. was tested as an alternative to the traditional potting mix used. The effects on mycorrhizal development and the morphometric assessment of the root and shoot system of the Q. pubescens seedlings were investigated eight months after the spore slurry inoculation in a glasshouse experiment. From the results obtained, the compost mix containing green organic residues from pruning and mowing (Mix 2) achieved better performance than the control and the potting mix based on composted municipal organic wastes, showing significantly higher mycorrhization percentage, root length, number of root tips, and root forks. In conclusion, a potting mix containing recycled green organic matter, which is readily available, cheap, and environmentally sustainable, can offer excellent mycorrhization performances and may be included in the mycorrhization process of downy oak seedlings with T. melanosporum under controlled conditions.

Microbiome - based agents can optimize composting of agricultural wastes by modifying microbial communities

Microorganisms that facilitate the decomposition of agricultural wastes are of importance during composting processes. Here, we assessed if microbial agents, comprising Clonostachys rosea, Bacillus amylolyticus and Rhodospirillum photometricum can facilitate the decomposition of a compost mix of vegetable waste, chicken manure, sawdust, and biochar. The results showed that inoculating the compost mix with the microbial agents elevated the compost temperature, increased the thermophilic period, and enhanced cellulose degradation. Microbial agent inoculation also changed the diversity and richness of decomposing microbial communities. Among the microbial agents, the mixture of C. rosea and B. amylolyticus performed better than other mixtures. Taken together, the results confirmed that the microbial agents comprising C. rosea can enhance the composting process by ameliorating the physiochemical conditions of agricultural wastes and promoting the diversity and proliferation of beneficial bacteria involved in the decomposition of cellulose.

Evaluating the potential of hydrochar as a soil amendment

In this study, hydrochar (HC), a carbon-rich product originated from hydrothermal conversion treatment (HTC), was obtained from wastes of the wine and dairy industries. The effect of mixing secondary char and compost was tested, before and after the aerobic mixing of compost (COM) and HC at increasing doses (from 15 to 75 Mg ha−1 DM), in an effort to lower the HC phytotoxicity due to potential phytotoxic compounds of secondary char. The results indicated that, after the aerobic stabilization, the mix HC/COM was able to double the plant growth in comparison to COM alone. The presence of easily degradable organic compounds probably led to poor stability of HC, increased microbial activity and, consequently, root anoxia when used at high doses. Chemical, spectroscopic and thermal investigation confirmed this hypothesis. In particular, HC shows a high content of dissolved organic matter, characterized by the presence of small molecules, which is negatively correlated with the growth index of lettuce. Furthermore, thermal characterization suggests a higher proportion of less complex and thermally stable molecular compounds in HC in comparison to COM. Therefore, co-composting of HC allows obtaining a useful amendment to support soil organic matter and fertility.

PM 3/66 (3) Guidelines for the management of plant health risks of biowaste of plant origin

<scp>PM</scp> 3/66 (3) Guidelines for the management of plant health risks of biowaste of plant origin

Correlation of microbial dynamics to odor production and emission in full-scale sewage sludge composting

Odor is inevitably produced during sewage sludge composting, and the subsequent pollution hinders the further development of composting technologies. Third-generation high-throughput sequencing was used to analyze microbial community succession, and the correlations between odor and microbial communities were evaluated. Hydrogen sulfide (47.5–87.9 %) and ammonia (9.4–49.9 %) contributed majorly to odor emissions, accounting for 93.7–98.5 % of the emissions. Volatile sulfur compounds were mainly produced in the mesophilic and pre-thermophilic phases (43.0–83.4 %), whereas ammonia was mainly produced in the thermophilic phase (52.1–59.4 %). Microorganisms dominant in the mesophilic and thermophilic phases correlated positively with odor production in the following order: Rhodocyclaceae > Clostridiaceae_1 > Hyphomicrobiaceae > Acidimicrobiales > Family_XI, whereas those dominant in the cooling phase showed negative correlations with odor production in the following order: Bacillus > Sphingobacteriaceae > Pseudomonadaceae > DSSF69 > Chitinophagaceae. The back mixing of mature compost is expected to serve as an economical measure for controlling odor during sewage sludge composting.

Nitrous oxide and carbon dioxide emissions from two soils amended with different manure composts in aerobic incubation tests

ABSTRACT Identification of nitrous oxide (N2O) and carbon dioxide (CO2) emissions from soils amended with different types of compost is needed for appropriate use of manure in agriculture. This study aimed at investigating the interaction effects of compost type and soil properties and effects of moisture contents on N2O and CO2 emissions, with identification of relative abundances of functional ammonia-oxidizing genes. Laboratory tests were conducted using cattle manure compost (CC) or mixed compost (MC) (cattle, poultry, and swine manure) amended Kochi (from a greenhouse) or Ushimado (from a paddy field) soils (3% by weight) with controls (no compost). Initial moisture contents were adjusted to 60% water-holding capacity (WHC) for Kochi soil and 70% WHC for both soils. The samples were aerobically incubated at 25°C. Emissions of N2O and CO2 and contents of ammonium N (NH4 +-N) and nitrate N in soils were measured continuously until day 42. The abundances of ammonia-oxidizing bacteria (AOB) and archaea genes were estimated to evaluate nitrifying activities. Cumulative N2O and CO2 emissions were significantly higher (p < 0.05) in MC than those in CC treatments probably due to higher NH4 +-N content and lower C/N ratio, which facilitated faster N mineralization and C decomposition. Emissions of N2O and CO2 were higher in compost-amended Kochi soil (70% WHC) with high total C and N, mineral N, and clay contents than those in less fertile Ushimado soil. Interestingly, interactions of compost type and soil properties on N2O emissions were significant (p < 0.05) only in Kochi soil because the addition of decomposition resistant CC increased N2O emissions only from this soil with high C and N contents. Higher soil moisture contents increased N2O and CO2 emissions significantly (p < 0.05) in Kochi soil. Emissions of N2O until day 15 were mainly due to activities of AOB amoA genes (R2 = 0.91). This study suggests that N2O emissions are increased by high NH4 +-N contents and a low C/N ratio in compost and high total C and N, mineral N, and clay contents in soil. The application of compost with less decomposable C increases N2O emissions only from nutrient-rich soil.