Wheat Straw Compost Research Articles

Eggplant growth in wheat straw-, wheat straw biochar- and compost-amended soils: a field study of CO2 emission dynamics, soil physicochemical, microbial, and nutrient effects

The growth of eggplant (Pusa Safed Baingan-1) was studied during the semi-arid (March to June) and humid sub-tropical (July to September) seasons of New Delhi, India. The individual effects of wheat straw biomass (WSBM), wheat straw biochar (WSBC) and compost versus the combined effect of WSBM plus compost and WSBC plus compost were determined under field conditions. The amendments were made at two different application rates: 1 wt% and 2 wt%. WSBC was successfully prepared in a proprietary kachcha reactor (Indian patent no. 380921), designed using locally sourced clay. Amendments were characterized using elemental analyzer, scanning electron microscopy (SEM), transmission electron (TEM) microscopy, Fourier transform infrared (FTIR) spectroscopy and X-Ray diffraction (XRD). The field study was conducted in 11 (1x1-meter) plots with two replicates. Basic soil health parameters including pH, electrical conductivity (EC), water holding capacity (WHC), bulk density (BD), cation exchange capacity (CEC), soil total nitrogen (STN), soil available nitrogen (SAN), soil organic carbon (SOC), soil available phosphorus (SAP), microbial biomass carbon (MBC) and mineral contents are analyzed. Observable plant growth characteristics (germination percentage, height, number of leaves, fruits, and plant biomass) were also recorded. Biochar amendment was most beneficial for enhancing the majority of these parameters. With respect to the control, a 20% decrease in bulk density, a 30% increase in water holding capacity, a 122% increase in organic carbon, a 175% increase in total nitrogen, a 23% increase in available nitrogen, and a 473% increase in available phosphorus were recorded. Furthermore, with respect to the control, a 115% increase in CEC was recorded using the compost amendment vs 84% with WSBC. Synergism between biochar and compost was reflected by high germination percentage (44%), number of fruits (600%), plant biomass weight (243%) and soil microbial biomass carbon (286%). Biomass amendment failed to show any positive influence. In summary, biochar emerges as a superior choice compared to both biomass and compost when it comes to soil amendments.

Application of Wheat Straw Compost Mixed with Chemical Fertilizer Regulates Soil Bacterial Community Diversity in Tea (Camellia sinensis) Plantation

Biofertilizers have been suggested as alternatives to synthetic fertilizers, which could reduce soil degradation brought on by excessive chemical fertilization and have an impact on the bacterial diversity and community in the soil. The diversity and community of soil bacteria in tea plantations treated with wheat straw compost have, however, received relatively little attention. In this research, a two-year field trial was run to examine the effects of applying wheat straw compost on the characteristics of the soil and the quality of the tea. We also used high-throughput sequencing to investigate the response of the soil bacterial community, and Spearman’s rank correlation was used to estimate the relationship between the soil bacterial community, soil characteristics, and tea quality. It was noticed that applying chemical fertilizer along with compost increased the fertility of the soil and the quality of the tea. Based on a two-year thorough data analysis, the T4 treatment (compost fertilizers 15,000 kg ha−1 + chemical fertilizers 1050 kg ha−1, chemical fertilizer reduction 30%) was determined to be the best group. The diversity and community makeup of soil bacteria were impacted by fertilization management. After the initial compost replacement, soils with compost had a greater bacterial richness than soils with inorganic fertilizers. After the second compost substitution, PCoA analysis revealed that compost fertilizer could be easily differentiated from chemical fertilizer. In 2019, Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, and Patescibacteria were the most prevalent bacterial phyla. In 2020, Firmicutes and Chloroflexi overtook Bacteroidetes and Patescibacteria as the two major bacterial phyla. In addition to increasing the diversity of soil bacteria and having an impact on the bacterial population, the application of wheat straw compost mixed with chemical fertilizers can also control the soil’s characteristics and the quality of the tea produced in tea plantations. So, as a fertilization way with less environmental impact, wheat straw compost fertilization can be used in tea plantations.

Effect of Different Tannery Sludge Composts on the Production of Ryegrass: A Pot Experiment

Background: Tannery industry produces high amounts of nutrient rich sludges that can be used as organic fertilizers. Objective: The aim of this study was to evaluate the fertilizing potential of composted tannery sludge. Methods: A pot experiment was carried out with ryegrass (Lolium perenne L.) to test two different composts: 2.0 kg dry matter (DM) tannery fatty sludge + 1.5 kg DM sheep manure + 1.5 kg DM wheat straw (Compost 1) and 2.0 kg DM tannery sludge + 1.5 kg DM sheep manure + 1.5 kg DM wheat straw (Compost 2). Five treatments, with three replicates each, were assigned: Control (C); Compost 1 at 6 t (C1-6) and 12 t (C1-12) DM ha-1; Compost 2 at 6 t (C2-6) and 12 t (C2-12) DM ha-1. Each treatment was applied in a pot and mixed with 5 kg of sieved soil (<2 mm). Results: Results showed that production of DM ranged between 1.2 t DM ha-1 for C1-6 and 2.4 t DM ha-1 for C2-12. The highest B, Na and N levels in ryegrass was observed in C2-12, with 175 mg kg-1 DM, 9 g kg-1 DM and 30 g kg-1 DM, respectively. At the end of the experiment no differences were observed between treatments for C, N, P2O5, and K2O levels. Differences were observed at Zn level ranged between 101 mg kg-1 DM for C1-6 and 71 mg kg-1 DM for C2-12. Conclusion: The C2-12 treatment was the best because induces higher DM production and nutrients in ryegrass and without dangerous concentration of heavy metals in soil. Composted waste from the tannery industry is a good source of nutrients for agriculture.

Impacts of size reduction and alkaline-soaking pretreatments on microbial community and organic matter decomposition during wheat straw composting

This study assessed the impacts of size reduction and alkaline-soaking pretreatments on microbial community shifts and organic matter decomposition in wheat straw composting. Bacterial communities were altered by alkaline soaking rather than size reduction, while fungal communities were altered by both pretreatments. Alkaline-soaking pretreatment promoted lignocellulosic saccharification and humification. A combination of both pretreatments increased the proportion of the fungal genus Coprinopsis (39%) at the early stage and promoted the proliferation of Ornithincoccus (15%) at the late stage. This facilitated the mineralization of ammonium N from amino acids; decreased the total lipids, free fatty acids, and nitrate N contents; and greatly improved the germination index of the final composting product to a high level of 149% as tested with radish seeds. The findings demonstrate that the combined application of size reduction and alkaline-soaking pretreatments is an effective strategy for improving the product quality of wheat straw compost.

Comparative study on oyster mushroom grown on composited substrate: The effect on yield, growing period and fruiting body size

Cultivation of the oyster mushroom on horse manure and wheat straw compost without nutrient supplementation was investigated. The growing, yield and fruiting body size effects on open trays and substrate bags were determined. Incubation and fruiting period on trays and inoculated bags were compared. The bagged compost yielded higher mushroom growth rate and yield than the tray compost. The fruiting bodies of the mushroom on trays were smaller, pile and thinner as compared to the mushrooms on the bags, which were bigger, fresh and strong. However, it was found that when oyster mushroom are grown on trays, the yield decrease, there is less moisture in the tray and substrate is exposed to heat, the pin head dries as they develop and those that succeed to grown further will grow as thin with a little head due to lack of oxygen. Comparing compost in bags with compost substrate in trays, bags yielded about 20% more mushrooms than trays under the same cultivation conditions. Conversely, the incubation period of compost in bags took longer, as compared to the incubation of compost in trays. Trays gave their first flash 10% earlier than the bags.

The functions of potential intermediates and fungal communities involved in the humus formation of different materials at the thermophilic phase

Humus is the final product of humus precursors (HPS) during the humification process, while the associated mechanisms of humus formation have not been clarified. Here, the HPS degradation intermediate and core fungal function for wheat straw and chicken manure compost (SCM), cow dung compost (CD), Chinese traditional medicine residue compost (CTM) and mushroom dreg and chicken manure compost (MCM) was investigated during the thermophilic phase. The results showed SCM and MCM were rich in proteins, lipids, cellulose, low-molecular-weight organic acids, while CD and CTM contained abundant carbohydrates, aliphatic compounds, easily biodegradable aromatic structures, and intermediates from the lignocellulose degradation. In particular, the HPS degrading intermediates including O-alkyl-C and aromatic C compounds were the critical factors, and Scedosporium, Hypsizygus and Remersonia were the core fungal genera for the humification. Furthermore, the potential fungal functional genes involved in carbohydrate and lignin degradation might be the key factors to drive the humification process.

A High-Throughput Imagery Protocol to Predict Functionality upon Fractality of Carbon-Capturing Biointerfaces

Surface quality is key for any adsorbent to have an effective adsorption. Because analyzing an adsorbent can be costly, we established an imagery protocol to determine adsorption robustly yet simply. To validate our hypothesis of whether stereomicroscopy, superpixel segmentation and fractal theory consist of an exceptional merger for high-throughput predictive analytics, we developed carbon-capturing biointerfaces by pelletizing hydrochars of sugarcane bagasse, pinewood sawdust, peanut pod hull, wheat straw, and peaty compost. The apochromatic stereomicroscopy captured outstanding micrographs of biointerfaces. Hence, it enabled the segmenting algorithm to distinguish between rough and smooth microstructural stresses by chromatic similarity and topological proximity. The box-counting algorithm then adequately determined the fractal dimension of microcracks, merely as a result of processing segments of the image, without any computational unfeasibility. The larger the fractal pattern, the more loss of functional gas-binding sites, namely N and S, and thus the potential sorption significantly decreases from 10.85 to 7.20 mmol CO2 g−1 at sigmoid Gompertz function. Our insights into analyzing fractal carbon-capturing biointerfaces provide forward knowledge of particular relevance to progress in the field’s prominence in bringing high-throughput methods into implementation to study adsorption towards upgrading carbon capture and storage (CCS) and carbon capture and utilization (CCU).

The physical structure of compost and C and N utilization during composting and mushroom growth in Agaricus bisporus cultivation with rice, wheat, and reed straw-based composts.

The cultivation of Agaricus bisporus with compost made from wheat (Triticum aestivum L.), rice (Oryza sativa L.), and reed (Phragmites australis Trin.) straw was investigated. Straw degradation was analyzed at the microscopic level, and the corresponding changes in the breakdown of different lignocellulose components during different phases of composting and mushroom production helped in understanding the yield-limiting factors of using different straws to grow mushrooms. The wheat straw compost resulted in the highest mushroom production and had the highest bioconversion efficiency. The rice straw was limited by the softer texture, which resulted in low-porosity and overdecomposed compost in the composting process and decreased the amount of available lignocellulose during mycelial growth. Although reed straw had the largest carbon resources, its utilization rate was the lowest. The hard structure, low water holding capacity, and high porosity increased the recalcitrance of reed straw to degradation and prolonged the composting time, which resulted in large N and C losses and an increased C/N ratio. Moreover, reed straw failed to transform into "ready-to-consume C" in composting. Therefore, a high C/N ratio and deficiency of available nutrition decreased the utilization efficiency of the lignocellulosic components by A. bisporus during mycelial colonization and mushroom production. The investigation revealed that degradability by and availability to microbiota and A. bisporus seemed to be the overriding factors for optimizing the composting process with different straw types. KEY POINTS: • The physical structure of compost has a significant influence on the composting process. • Degradability and availability are key factors in compost quality evaluation. • Lignocellulose utilization efficiency positively correlated with mushroom yield.

Survival Rates of Microbial Communities from Livestock Waste to Soils: A Comparison between Compost and Digestate

Livestock waste-based products, such as composted manure, are often used in crop production systems. The products’ microbial characteristics differ depending on animal waste treatment methods used (e.g., biogas production/composting). The question remains whether different livestock waste-based products differently impact soil microbiota. A pot experiment with five treatments (control, chemical fertilizer, digestate + chemical fertilizer, wheat straw compost + chemical fertilizer, and woodchip compost + chemical fertilizer) was conducted to compare the survival rates of microbial communities from digestate and composted manure, after their application to agricultural soil. Potatoes were planted in each pot. The changes in soil pH, the concentration of ammonium and nitrate, and the microbial community properties were monitored after 1, 6, 10, and 14 weeks of the application of livestock waste-based products. The application of composted manure, especially woodchip compost, showed a relatively more extensive impact on the soil microbial community structure than the other treatments. Woodchip compost contained a relatively more abundant and diverse bacterial community than digestate, and its family-level bacterial community structure was similar to that of the soil. These characteristics might determine the extent of the impact of livestock waste-based products on soil microbial communities. Digestate markedly influenced the inorganic nitrogen concentrations in soils but did not affect the soil microbial community. In conclusion, the survival rate of microbes of livestock waste-based products varies depending on the product type. Further investigation is needed to fully understand their impact on soils’ microbial functions.

Efficiency of Wheat Straw Biochar in Combination with Compost and Biogas Slurry for Enhancing Nutritional Status and Productivity of Soil and Plant.

In the present study, we investigated the impact of different combinations of wheat straw biochar, compost and biogas slurry on maize growth, physiology, and nutritional status in less productive soils. The experiment was performed as a completely randomized block design in a greenhouse pot experiment. The compost and biogas slurry were applied with and without biochar. The results revealed that a combination of biochar, compost, and biogas slurry enhanced the cation exchange capacity (31%), carbon (83%), phosphorus (67%) and potassium (81%) contents in the soil. Likewise, a significant increase in soil microbial biomass carbon (15%) and nitrogen (37%) was noticed with the combined use of all organic amendments. Moreover, the combined application of biochar, compost and biogas slurry enhanced soil urease and β-glucosidase activity up to 96% and 67% over control respectively. In addition, plant height, chlorophyll content, water use efficiency and 1000-grain weight were also enhanced up to 54%, 90%, 53% and 21% respectively, with the combined use of all amendments. Here, biochar addition helped to reduce the nutrient losses of compost and biogas slurry as well. It is concluded that biochar application in combination with compost and biogas slurry could be a more sustainable, environment-friendly and cost-effective approach, particularly for less fertile soils.

Bacterial ecosystem functioning in organic matter biodegradation of different composting at the thermophilic phase

This study aimed to provide insights into prediction of composting ecological functioning through analyzing the critical bacterial populations and functions. The bacterial ecosystem functioning was essential, and cow dung, chicken manure, mushroom dreg and Chinese medicine residues were used as raw materials to quantify and predict the functioning of bacterial communities through synthetic spike-in standards accompanied Illumina sequencing and PICRUSt. Bacterial community of wheat straw and chicken manure compost (SCM) was similar to mushroom dreg and chicken manure compost (MCM), and Sinibacillus dominated in both treatments with the abundance of 20.73% and 41.36%, respectively. The correlation analysis between bacterial community and fluorescence EEM regional integration parameters showed that Lactobacillus (0.889), Enterococcus (0.888) and Erysipelothri (0.903) were positively correlated with PV, n / PIII, n. The ontology analysis results showed that metabolism, genetic information processing, environmental information processing and cellular processes were the primary functions for bacterial community in all treatments.

Influence of inorganic additives on wheat straw composting: Characterization and structural composition of organic matter derived from the process

Metallic oxides and clay minerals have gained increasing interest as additives of composting due to their influence in greenhouse gas emissions reduction and their effectivity in the stabilization of carbon both in compost and soils, leading to a cleaner compost production and potentially C sequestrant amendments. In this study, wheat straw (WS) was co-composted with iron oxide and allophanic soil and their influence on WS composting and composition of the end-products was evaluated. WS compost and their humic like-substances (HS) fraction were characterized by chemical and spectroscopic analyzes. After 126 days of process, the elemental composition showed slight differences of the N content for compost and HS, where the C/N atomic ratio tended to decrease relative to the initial material (WS; ~130). This trend was more pronounced in the HS from co-composted treatments (<30). The addition of inorganic materials increased the total acidity and phenolic-OH group contents (~15 and 14 mEq g−1 respectively, iron oxide treatment) relative to the treatment without inorganic additives. Nevertheless, the FTIR and solid-state 13CNMR spectroscopy barely support the wet chemical analysis and revealed a similar final composition between all the studied compost treatments. These results suggest that the incorporation of these materials as compost additives had no major effect on the spectroscopic features of the end-products, however, critical changes of the properties such as the extractability, functionality and composition of HS were revealed by traditional methods. In conclusion, the supply of metal oxides and clays could impact the aerobic composting of WS favorizing the stabilization of certain C pools and adsorptive properties of the end-products, that is of importance in production of amendments suitable for being used in degraded and contaminated soils. Nevertheless, under the experimental conditions of our research C stabilization apparently depends of other mechanisms that still need to be elucidate.

Metagenomic insights into effects of wheat straw compost fertiliser application on microbial community composition and function in tobacco rhizosphere soil

The application of fertilisers incorporated with plant residues improves nutrient availability in soils, which shifts the microbial community structure and favours plant growth. To understand the impact of wheat straw compost fertiliser on soil properties and microbial community structure, tobacco planting soils were treated with four different fertilisers using varied amounts of straw compost fertiliser and a no fertiliser control (CK). Results showed that different fertilisers affected available soil nutrient contents differently. Treatment of tobacco soil with application of combined chemical fertiliser/wheat straw compost led to improved soil chemical properties, and increased soil organic matter and available phosphorus and potassium content. Treatment with FT1 200 kg/mu straw was found to be superior in improving soil fertility. Metagenomic DNA sequencing revealed that different fertiliser treatments resulted in changes in the microbial community composition. In soil treated with FT2 300 kg/mu straw for 60 days, the predominant bacterial phyla were Proteobacteria, Actinobacteria, and Verrucomicrobia, whereas Cyanobacteria, Basidiomycota, and Chlorophyta were found in high abundance in soil samples treated with FT1 200 kg/mu straw for 30 days. Functional annotation of metagenomic sequences revealed that genes involved in metabolic pathways were among the most abundant type. PCoA analysis clearly separated the samples containing straw compost fertiliser and chemical fertiliser. A significant correlation between soil properties and the dominant phyla was identified.

Diversity of Bacterial and Fungal Communities in Wheat Straw Compost for Agaricus bisporus Cultivation

The Agaricus genus represents the most popular edible mushroom in the world. Wheat straw often is used as the substrate for mushroom cultivation following pretreatment to degrade the lignocellulosic biomass in agricultural waste. In this study, we investigated the changes in bacterial and fungal microflora of wheat straw substrate during different phases of composting. We collected samples of the raw material (M1), phase I aerobic fermentation (F1, F2, F3), and phase II after-fermentation (AF1) for high-throughput 16S rRNA and internal transcribed spacer (ITS) sequencing to analyze the microbial diversity in the substrate during composting. Our data revealed that among the five stages, 365 operational taxonomic units (OTUs) were shared, with Firmicutes, Proteobacteria, and Actinobacteria being the predominant bacterial phyla. In addition, Thermobispora, Thermopolyspora, Ruminiclostridium, Thermobacillus, and Bacillus were the predominant genera in F3 and AF1, with the species Thermobispora bispora and Pseudoxanthomonas taiwanensis being predominant in F2. Both principal component analysis (PCA) and nonmetric multidimensional scaling (NMDS) plots showed that the bacterial communities of five stages could be distinguished from each other based on their composting time. The Shannon and Simpson indexes of F2 were lower than M1 (P &lt; 0.05), and the clustering dendrogram showed that the bacterial communities in AF1 were similar to F3, with Micromonosporaceae, Streptosporaceae, Thermomonosporaceae, and Vulgatibacteraceae representing the differential bacterial families by linear discriminant analysis with effect size (LEfSe) analysis. The analysis of fungal communities showed that 384 OTUs were common among the five stages, with 1054 and 454 OTUs unique to M1 and AF1, respectively. Ascomycota and Basidiomycota were the two predominant phyla in all stages, and Chytridiomycota was predominant in F2, F3, and AF1 stages. PCA and NMDS plots showed that the clusters of F2 and AF1 were more dispersed than the other stages. No differences were observed in alpha diversity between the stages, and samples of F1, F2, and F3 were closer to AF1 in the clustering dendrogram. By LEfSe analysis, Mycothermus thermophilus, Gonapodya polymorpha, and Phaeophleospora_eugeniae were identified as the predominant fungal species in AF1.

Defining functional diversity for lignocellulose degradation in a microbial community using multi-omics studies

BackgroundLignocellulose is one of the most abundant forms of fixed carbon in the biosphere. Current industrial approaches to the degradation of lignocellulose employ enzyme mixtures, usually from a single fungal species, which are only effective in hydrolyzing polysaccharides following biomass pre-treatments. While the enzymatic mechanisms of lignocellulose degradation have been characterized in detail in individual microbial species, the microbial communities that efficiently breakdown plant materials in nature are species rich and secrete a myriad of enzymes to perform “community-level” metabolism of lignocellulose. Single-species approaches are, therefore, likely to miss important aspects of lignocellulose degradation that will be central to optimizing commercial processes.ResultsHere, we investigated the microbial degradation of wheat straw in liquid cultures that had been inoculated with wheat straw compost. Samples taken at selected time points were subjected to multi-omics analysis with the aim of identifying new microbial mechanisms for lignocellulose degradation that could be applied in industrial pre-treatment of feedstocks. Phylogenetic composition of the community, based on sequenced bacterial and eukaryotic ribosomal genes, showed a gradual decrease in complexity and diversity over time due to microbial enrichment. Taxonomic affiliation of bacterial species showed dominance of Bacteroidetes and Proteobacteria and high relative abundance of genera Asticcacaulis, Leadbetterella and Truepera. The eukaryotic members of the community were enriched in peritrich ciliates from genus Telotrochidium that thrived in the liquid cultures compared to fungal species that were present in low abundance. A targeted metasecretome approach combined with metatranscriptomics analysis, identified 1127 proteins and showed the presence of numerous carbohydrate-active enzymes extracted from the biomass-bound fractions and from the culture supernatant. This revealed a wide array of hydrolytic cellulases, hemicellulases and carbohydrate-binding modules involved in lignocellulose degradation. The expression of these activities correlated to the changes in the biomass composition observed by FTIR and ssNMR measurements.ConclusionsA combination of mass spectrometry-based proteomics coupled with metatranscriptomics has enabled the identification of a large number of lignocellulose degrading enzymes that can now be further explored for the development of improved enzyme cocktails for the treatment of plant-based feedstocks. In addition to the expected carbohydrate-active enzymes, our studies reveal a large number of unknown proteins, some of which may play a crucial role in community-based lignocellulose degradation.

Guar, jantar, wheat straw, and rice hull composts as replacements for peat in muskmelon transplant production

The demand for soilless media for vegetable transplant production is increasing. Economic constraints paired with concerns over the sustainability of peat mining have necessitated the replacement of peat with renewable and regionally abundant alternatives. The aim of this study was to develop from composts complete or partial substitutes for peat. Composted guar (Cyamopsis tetragonoloba), jantar (Sesbania aculeata), wheat (Triticum aestivum) straw, and rice (Oryza sativa) hulls adjusted to 10% air-filled porosity (AFP) were blended on a volumetric basis with peat moss at discrete levels (0–50%). Total water-holding capacity, shrinkage, dry and wet bulk density, pH, electrical conductivity, N, P, K, FE, B, and Zn concentrations of each compost, their blends, and a peat control were measured. The experimental media were used to grow muskmelon (Cucumis melo) plants in a greenhouse. Seed germination, shoot fresh weight, shoot height, leaf area, stem diameter, root length, and mineral nutrient concentrations of transplants were quantified. After transplanting in the field, the growth rates and yields were measured. Nonparametric regression was used to analyze the data. The physiochemical parameters measured for most of the experimental media fell within the recommended range for growing media; however, pH for all media exceeded the recommended range. Media-containing guar and jantar composts generally contained more nutrients than media-containing rice hull or wheat straw composts. Fresh weight, height, and root length were generally greater for seedlings grown in media-containing rice hull compost than for those grown in media-containing other composts. Seedlings grown in media-containing guar or jantar composts generally had greater tissue nutrient concentrations. All blends produced acceptable seedlings; however, the largest seedlings, and greatest post-transplant growth rate and yield were produced in media containing 30–50% rice hull compost.

N2O and CO2 emissions from South German arable soil after amendment of manures and composts

Organic residues can be a major source of nutrients and are valuable fertilizers. But their benefits with regard to soil quality are undisputed. However, only few studies have focused on emissions of greenhouse gases from soil enriched with organic residues. A microcosom approach was employed to investigate the influence of the origin and composition of various organic residues on mineralization and N2O and CO2 emissions in an arable soil. In total, we set up six treatments: control, poultry manure, bio-waste compost, sheep and wheat straw compost, cow manure (CM) and for further comparison, the mineral fertilizer calcium ammonium nitrate. 500 g of sieved and homogenized soil was mixed with the amendments and packed into microcosms. After a pre-incubation period of 10 days, gas concentrations were measured periodically from the headspace of the microcosm by means of an airtight surgical syringe. The measurement period continued for 32 days. Soil amended with CM showed a significantly (α = 0.05) higher cumulative CO2 emission (914 mg kg−1) followed by bio-waste compost than poultry manure, sheep waste compost, control and calcium ammonium nitrate. Amending soil with cow manure and poultry manure led to the highest N2O-N emissions (110 µg kg−1). However, poultry manure and calcium ammonium nitrate significantly enhanced mineralization and net nitrification. Amendment of sheep and wheat straw compost and cow manure led to C sequestration and reduced N2O emission. Soil pH greatly decreased with poultry manure, sheep and wheat straw compost and bio-waste compost. Summing up, the application of organic residues to soil has some disadvantageous environmental effects calling for further research.

English

Dry bubble disease induced by Verticillium fungicola has been observed as an important disease of white button mushroom (Agaricus bisporus) in India. The symptoms produced on differentiated fruit body are localized light brown depressed spots. The adjacent spots coalesce together and form irregular blotches. If the pathogen infection is established before differentiation, sclerodermoid fruiting bodies appear on casing surface. Five plant extracts tested by poisoned food technique inhibited the growth of both host and pathogen. But their cumulative effect was found to improve the mushroom yield. Azadirachta indica (Neem) effectively controlled the pathogen and increased the yield of white button mushroom by 16.52% compared to control. Key words: Agaricus bisporus, Verticillium fungicola, dry bubble, wheat straw compost, compost, long method of composting, short method of composting,&nbsp; Azadirachta indica, Parthenium parthefolium.

Description of Comamonas serinivorans sp. nov., isolated from wheat straw compost.

A Gram-stain-negative bacterium, designated SP-35(T), was isolated from compost and was subjected to a taxonomic study. This isolate was short-rod-shaped and non-spore-forming. Phylogenetic analysis based on 16S rRNA sequence comparison indicated the isolate was related to the genus Comamonas. 16S rRNA gene sequence analysis showed that its closest neighbours were the type strains Comamonas odontotermitis Dant 3-8(T) (96.8 % similarity), Comamonas testosteroni DSM 50244(T) (96.5 %), Comamonas guangdongensis CY01(T) (95.9 %) and Comamonas composti YY287(T) (95.6 %). Using phylogenetic analysis, DNA-DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristics we could clearly distinguish strain SP-35(T) from type strains of the genus Comamonas. The genomic DNA G+C content of strain SP-35(T) was 63.1 mol%. The predominant cellular fatty acids were C16 : 0, C17 : 0 cyclo, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidlyglycerol. Differences in phenotypic and phylogenetic characteristics support the classification of strain SP-35(T) as a representative of a novel species in the genus Comamonas, for which the name Comamonas serinivorans sp. nov. is proposed. The type strain is SP-35(T) ( = DSM 26136(T) = JCM 18194(T)).

Organic carbon and nitrogen stocks in a clay loam soil 10 years after a single compost application

Yang, X., Reynolds, W. D., Drury, C. F., Fleming, R., Tan, C. S., Denholm, K. and Yang, J. 2014. Organic carbon and nitrogen stocks in a clay loam soil 10 years after a single compost application. Can. J. Soil Sci. 94: 357–363. Household food waste compost (FWC), yard waste compost (YWC) and pig manure plus wheat straw compost (PMC) were applied once in the fall of 1998 to a Brookston clay loam soil in southwestern Ontario to determine immediate and long-term effects of organic amendments on soil quality and productivity. In this report, we describe the residual effects of these single compost applications on soil organic carbon (SOC) and total soil nitrogen (TN) stocks 10 yr after compost addition (2009). FWC was applied at 75 Mg ha−1, 150 Mg ha−1 and 300 Mg ha−1, while YWC and PMC were applied at the single rate of 75 Mg ha−1. The 75 Mg ha−1 additions of YWC, PMC and FWC increased SOC in the top 30 cm relative to a control (no compost additions) by 12.3% (9.0 Mg ha−1), 16.6% (12.2 Mg ha−1) and 0%, respectively; and they increased TN relative to the control by 8.0% (0.53 Mg ha−1), 11.7% (0.77 Mg ha−1), and 0%, respectively. The 150 and 300 Mg ha−1 additions of FWC increased SOC in the top 30 cm by 13.0 and 24.7 Mg ha−1, respectively, and they increased TN by 0.93 and 1.70 Mg ha−1, respectively. These results indicate that increases in SOC and TN stocks accruing from a single compost addition can persist for at least a decade, but the degree of increase depends strongly on compost type and addition rate. It was concluded that high compost addition rates of FWC and/or addition of composts derived from recalcitrant organic materials may be a good strategy for achieving long-term carbon and nitrogen sequestration in the cool, humid fine-textured soils of southwestern Ontario.