Compost Nitrogen Research Articles

Exploring compost production potential and its economic benefits and greenhouse gas mitigation in Addis Ababa, Ethiopia

The increasing amount of municipal organic waste (MOW) and human excreta (HE) has led to socio-economic and environmental challenges in the cities of developing countries. This study estimated MOW and HE, compost production potential from MOW and HE, and compost application potential for urban agriculture fertilization, economic benefits, soil carbon sequestration, and greenhouse gas (GHG) mitigation in Addis Ababa, Ethiopia, for the period 2025–2050. MOW was forecasted using the Holt-Winters forecasting model. HE was estimated using the daily average rate of HE generation. The compost production potential was estimated using the forecasted MOW and HE. Compost fertilization was determined by considering compost nitrogen (N), phosphorus (P), and potassium (K) and the fertilizer requirements of cereals and vegetables. The economic benefits of compost were determined by considering the price of compost-equivalent urea, NPS, and potassium chloride fertilizers. The mitigation of GHG emissions from compost application was estimated using the IPCC Tier 1 method. The forecasted quantities of MOW, HE, and compost for 2050 are 301, 462, and 343 Gg, respectively. The compost could supply 5 Gg of N and 2.2 Gg of P in 2050, sufficient to fertilize 14,129 ha of vegetable fields. The economic benefits of using compost as a substitute for synthetic fertilizers could reach 10 million USD in 2050. Compost production and application could offset the total GHG emissions of Addis Ababa by 13.1 % (10,241Gg CO2-eq year−1) in 2050. The application of compost generated from MOW and HE in Addis Ababa can substitute synthetic fertilizers, provide economic benefits, and mitigate GHG emissions.

Impacts of Compost Amendment Type and Application Frequency on a Fire-Impacted Grassland Ecosystem

Composting organic matter can lower the global warming potential of food and agricultural waste and provide a nutrient-rich soil amendment. Compost applications generally increase net primary production (NPP) and soil water-holding capacity and may stimulate soil carbon (C) sequestration. Questions remain regarding the effects of compost nitrogen (N) concentrations and application rates on soil C and greenhouse gas dynamics. In this study, we explored the effects of compost with different initial N quality (food waste versus green waste compost) on soil greenhouse gas fluxes, aboveground biomass, and soil C and N pools in a fire-impacted annual grassland ecosystem. Composts were applied annually once, twice, or three times prior to the onset of the winter rainy season. A low-intensity fire event after the first growing season also allowed us to explore how compost-amended grasslands respond to burning events, which are expected to increase with climate change. After four growing seasons, all compost treatments significantly increased soil C pools from 9.5 ± 0.9 to 30.2 ± 0.7 Mg C ha−1 (0–40 cm) and 19.5 ± 0.9 to 40.1 ± 0.7 Mg C ha−1 (0–40 cm) relative to burned and unburned controls, respectively. Gains exceeded the compost-C applied, representing newly fixed C. The higher N food waste compost treatments yielded more cumulative soil C (5.2–10.9 Mg C ha−1) and aboveground biomass (0.19–0.66 Mg C ha−1) than the lower N green waste compost treatments, suggesting greater N inputs further increased soil stocks. The three-time green waste application increased soil C and N stocks relative to a single application of either compost. There was minimal impact on net ecosystem greenhouse gas emissions. Aboveground biomass accumulation was higher in all compost treatments relative to controls, likely due to increased water-holding capacity and N availability. Results show that higher N compost resulted in larger C gains with little offset from greenhouse gas emissions and that compost amendments may help mediate effects of low-intensity fire by increasing fertility and water-holding capacity.

Effects of adding corn steep liquor on bacterial community composition and carbon and nitrogen transformation during spent mushroom substrate composting

BackgroundCarbon and nitrogen are essential energy and nutrient substances in the composting process. Corn steep liquor (CSL) is rich in soluble carbon and nitrogen nutrients and active substances and is widely used in the biological industry. Nonetheless, limited research has been done on the effect of CSL on composting. This work firstly reveals the effect of adding CSL to bacterial community composition and carbon and nitrogen conversion during composting. This study provides the choice of auxiliary materials for the spent mushroom substrate compost (SMS) and some novel knowledge about the effect of bacterial community on C and N cycling during composting of SMS and CSL. Two treatments were set up in the experiment: 100% spent mushroom substrate (SMS) as CK and SMS + 0.5% CSL (v/v) as CP.ResultsThe results showed that the addition of CSL enhanced the initial carbon and nitrogen content of the compost, altered the bacterial community structure, and increased the bacterial diversity and relative abundance, which might be beneficial to the conversion and retention of carbon and nitrogen in the composting process. In this paper, network analysis was used to screen the core bacteria involved in carbon and nitrogen conversion. In the CP network, the core bacteria were divided into two categories, synthesizing and degrading bacteria, and there were more synthesizing bacteria than degrading bacteria, so the degradation and synthesis of organic matter were carried out simultaneously, while only degrading bacteria were found in the CK network. Functional prediction by Faprotax identified 53 groups of functional bacteria, among which 20 (76.68% abundance) and 14 (13.15% abundance) groups of functional bacteria were related to carbon and nitrogen conversion, respectively. Adding CSL stimulated the compensatory effect of core and functional bacteria, enhanced the carbon and nitrogen transformation ability, stimulated the activity of low-abundance bacteria, and reduced the competitive relationship between the bacterial groups. This may be why the addition of CSL accelerated the organic matter degradation and increased carbon and nitrogen preservation.ConclusionsThese findings indicate that the addition of CSL promoted the cycling and preservation of carbon and nitrogen in the SMS composts, and the addition of CSL to the compost may be an effective way to dispose of agricultural waste.

ЭФФЕКТИВНОСТЬ РАЗЛИЧНЫХ РЕЖИМОВ ИНТЕНСИВНОЙ АЭРОБНОЙ ПЕРЕРАБОТКИ КОМПОСТНЫХ СМЕСЕЙ НА ОСНОВЕ ОСАДКА СТОЧНЫХ ВОД

The article defines the efficiency of using various modes of intensive aerobic processing of compost mixtures based on sewage sludge (WWS) into biocomposts. The use of intensive aerobic processing in comparison with traditional composting technologies made it possible to reduce the loss of organic matter and nitrogen in compost based on WWS by half. Complete disinfection of the compost mixture based on WWS from pathogenic vegetative microflora is achieved by its aerobic processing in thermophilic mode (at a temperature of 55°C and above) for 48 hours.

Optimization strategies for mitigating nitrogen loss in the aerobic composting of pig manure and microbial changes revealed by metagenomic analysis

In this research, comprehensive optimization strategies for mitigating nitrogen loss in pig manure compost was screened out and nitrogen cycle microbial changes revealed by metagenomic technology. Results showed the optimum combination of process conditions as C/N ratio of 25, turning frequency of twice/day, addition of biochar and inoculation with nitrogen retaining microbial agent. The nitrogen loss rate of the optimized group was 14.67%, which was 45.33% significantly lower than that of the traditional group. NH3, N2O, and NO emission significantly decreased by 42.74%, 48.93%, and 69.95%. Metagenomic analysis revealed that process optimization could change the microbial community, functional genes and metabolism pathways of the nitrogen cycling in the composting process. Nitrogen loss was mainly mitigated by increasing the enzyme activities in nitrogen assimilation (increased by 11.80%), nitrification (increased by 39.35%), and nitrogen fixation pathways (increased by 74.72%) and reducing the enzyme activities in denitrification pathways (decreased by 35.20%). The findings provided reference markers for further exploration of compost nitrogen loss. This comprehensive optimization strategies method for mitigating nitrogen loss was recommended in aerobic composting of pig manure.

Metagenomics analysis unraveled the influence of sulfate radical-mediated compost nitrogen transformation process.

The mechanism of nitrogen transformation of sulfate radical (SO- 4⋅) in the process of composting is unclear. The objectives of this study were to investigate the influence of SO- 4⋅ on nitrogen biotransformation during composting and to compare the differences in physicochemical parameters and metagenomics analysis between CK (fresh dairy manure and bagasse pith) and PS (the composting raw materials added with potassium persulfate). The results indicated that SO-4⋅ guides electron transfer in the conversion of NH+4-N to NO- 3-N and breaches the extracellular polysaccharide (EPS) structure to promote nitrogen removal. Aminomonooxygenase (AMO) and nitrate reductase (NR) levels displayed an interactive relationship between microorganisms and substrates. Metagenomics analysis revealed distinct microbial community compositions and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between nitrification and denitrification. Correlation analysis indicated that Methanobrevibacter, Bacillus and Pseudomonas were closely related to these processes. This work demonstrates the effect of SO- 4⋅ on nitrogen cycling and retention, and possible mechanisms of nitrification and denitrification during composting.

Red mud conserved compost nitrogen by enhancing nitrogen fixation and inhibiting denitrification revealed via metagenomic analysis

The objective of this study was to investigate the effects of adding red mud (RM) on denitrification and nitrogen fixation in composting. The results revealed that the retentions of NH4+-N and NO3–-N in experimental group (T) with RM were 16.20% and 7.27% higher than that in control group (CK) at the mature stage, respectively. The composition and structure of RM can effectively inhibit denitrification and enhance nitrogen fixation. Moreover, metagenomic analysis revealed that Actinobacteria and Proteobacteria were the main microorganisms in denitrification process, while Firmicutes were the main microorganisms in nitrogen fixation process. In T, denitrifying genes nirK and nosZ were 11% and 18% lower than those in CK, respectively, while nitrogen-fixing genes nifK and nifD were 18% and 34% higher than those in control group, respectively. Therefore, adding RM could reduce nitrogen loss and improve the quality of compost via enhancing nitrogen fixation and inhibiting denitrification process.

ACTIVITY OF ENZYMATIC CELLULOLYTIC COMPLEX AND ANTAGONISTIC PROPERTIES OF TRICHODERMA HARZIANUM 128

Objective. To study the activity of enzymes of the cellulolytic complex of the association of micromycetes Trichoderma harzianum 128 and their antagonistic activity; to study the possibility of the influence of fungal introduction to the composted substrate on the composting rate and quality of composts. Methods. Microbiological (for growing micromycetes in digest media, accounting the number of T. harzianum 128 and determining the antagonistic activity of the association), agrochemical (to determine the characteristics of composting chicken manure-based substrates and content of carbon and nitrogen in these substrates), biochemical (study of activity of cellulolytic enzymes), production inspection (on the basis of Agrofirma KOLOS LLC, Region of Kyiv). Results. The association of T. harzianum 128 micromycetes is characterized by high activity of exoglucanase, endoglucanase and β-glucosidase, which contributes to reduction in the composting time of organic matter upon the introduction of fungi to the chicken manure-based substrate. T. harzianum 128 has pronounced antifungal properties against pathogens of certain diseases of crops (Fusarium oxysporum, F. sulfurum, Nigrospora oryzae). Enrichment of composted substrates with the studied micromycetes provides their active development (up to 8,150 thous CFU/g of dry compost), accumulation of carbon and nitrogen in compost, which improves the quality of the final product. Conclusion. The association of T. harzianum 128 micromycetes is characterized by high activity of enzymes of the cellulolytic complex, has a pronounced antagonistic activity against pathogens of certain diseases of crops. The introduction of T. harzianum 128 to composted chicken manure-based substrates reduces the composting time and improves the quality of the final product, which can increase the productivity of agrocenoses by including biofertilizers in crop fertilization systems.

A microbial agent effectively reduces ammonia volatilization and ensures good maggot yield from pig manure composted via housefly larvae cultivation

Ammonia volatilization is a serious concern in the two-stage composting of pig manure. To reduce ammonia volatilization, an optimal microbial agent concentration for maintaining nitrogen in compost was determined. The microbial agent had a negative effect on housefly larval growth, but all treatments achieved good yields of late-instar maggots above 12% fresh material weight. The volatilization of ammonia was efficiently reduced by directly mixing 1% microbial agent into the initial material, and the ammonia volatilization within the monitoring time was decreased by 60.7% and 68.2% in T3 (undiluted microbial fermentation liquid) and T2 (10-fold diluted microbial fermentation liquid) on day 4, respectively, compared with that of T0 (the same volume of water without microbial agent). The total nitrogen loss from fermentation in T3 was reduced by 44.76% by day 6 compared with that in T0 but decreased only by 17.12% upon the completion of composting. Maggot breeding had a substantial effect on the microbial population structure in the materials. According to the changes in the total organic carbon content, soluble carbon content, and seed germination index, the composting process should be completed within 3–4 w to retain optimal organic carbon and nitrogen contents. Our results highlight that the microbial agent beneficially not only reduces ammonia volatilization and the total nitrogen loss but also ensures good maggot yield from pig manure composted via housefly larvae cultivation.

The effect of chitosan, arbuscular mycorrhizal fungi, and compost applied individually or in combination on growth, nutrient uptake, and stem anatomy of tomato

This study investigated the effect of chitosan and a complex of arbuscular mycorrhizal fungi (AMF) on tomato plant (Solanum lycopersicum) grown in soil with four doses of compost (C0%, C5%, C10%, and C20%).Scanning electron microscopy with energy dispersive x-ray analysis revealed the interaction of NH2 groups of chitosan with compost nitrogen that was increased by 80% after 24 h of cross-linking. Growth and physiological parameters (root length, fresh and dry biomass of shoot and root, leaf area and Fv/Fm) and biochemical parameters (sugar and protein content) were improved in mycorrhizal plants grown in soil amended with chitosan and 10% of compost (Ch+C10%M+) compared to control plants (ControlC0%M−). This improvement was correlated with the increase of the diameter and the number of xylem vessels of tomato stems. In addition, the application of chitosan and AMF together on plants grown in a poor soil of mineral elements (Ch+C0%M+), increases the stem cortex that is involved in the distribution of minerals.Chitosan application with AMF and 10% of compost was found to be the best treatment for tomato growth. Therefore, adjusting soil with these three bio-fertilizers could be an interesting agricultural tool to help plants adapt in poor soil.

Validation of sample preparation for spectrometric determination of urea-form nitrogen in compost

Validation of sample preparation for spectrometric determination of urea-form nitrogen in compost

Humification of poultry waste and rice husk using additives and its application

PurposeThe purpose of this study was to assess the efficacy of inorganic additives during the humification of poultry waste and rice husk.MethodsPoultry waste mixture was treated with aluminum sulfate 3% and rock phosphate 2% during co-composting of mixture in mechanical composter and evaluated the potential of humification and compost nitrogen mineralization in incubation and pot study.ResultsThe mesophilic to thermophilic phase of composting mixture is prolonged due to the rise in temperature, pH and ammonia that steadily decrease near the maturation phase. The humification rate (HR), humification index (HI), degree of polymerization (DP) and cation exchange capacity (CEC) increased in enriched compost as compared to unenriched with the composting process. The germination index (GI) of enriched compost (C/N:10.8) was significantly greater than unenriched compost (C/N:23.43). These all maturity indices, i.e., C/N, CE, HI, DP, HR revealed the significant correlation with each other. In the incubation study, nitrogen mineralization was also evaluated and nitrogen was applied at the rate of 50 kg-N/ha using the enriched and unenriched compost and found high mineralization in enriched compost due to low C/N. A laboratory-scale pot experiment was also conducted, applied the compost at a rate of 100 kg-N/ha and recorded the encouraging results in growth and nutrition value of Abelmoschus esculentus plant.ConclusionIt was concluded that use of additives have a significant impact on humification of poultry waste.

Hydrochars as peat substitute in growing media for organically grown potted herbs

Due to extensive media coverage of the “Terra Preta” soils found in the Amazon basin and the role of charcoal for their high fertility, carbonization of biomass is of increasing interest. In this context “biochar” made by pyrolysis and made by hydrothermal carbonization (HTC) have to be distinguished. The main advantage of the HTC process is the broader range of suitable raw materials because in addition to dry, also wet or water rich organic material can be used. Up to now research has focused on hydrochars as soil improvers at relative low application rates. In contrast, the aim of the current research was the use of hydrochars from woody landscaping material as well as from a mixture of woody landscaping material and grass as peat substitutes in growing media at 20-100% by volume. At 30% by volume, hydrochar significantly reduced growth of potted basil. At a higher percentage, growth after germination almost ceased. Subsequent experiments with chinese cabbage, lettuce and barley as well as an incubation test revealed that a strong immobilization of nitrogen is the main reason for reduced growth, but additionally both hydrochars seem to contain some phytotoxic substances. During co-composting of hydrochars with mature green waste compost nitrogen immobilization is reduced and phytotoxic substances are degraded within a few weeks. The results are in accordance with findings for the use of hydrochars as soil improvers, where often a loss of growth was caused directly after application of hydrochars, but some time later yield was increased. Risks and opportunities of hydrochars as peat substitutes in growing media are discussed.

Apple pomace improves the quality of pig manure aerobic compost by reducing emissions of NH3 and N2O

In this study, the effects of apple pomace (AP) addition (0%, 5%, 10%, and 20% on a dry weight basis, named as control, AP1, AP2, and AP3) and citric acid (CA) addition on nitrogen conservation were investigated during aerobic composting of pig manure. Gaseous emissions of NH3 and N2O were inhibited by AP and CA addition, with AP’s effect greater. The inhibition improved with increasing AP addition. The AP3 treatment was the most effective on NH3 adsorption and transformation to {{bf{NH}}}_{{bf{4}}}^{{boldsymbol{+}}}-N, improved with subsequent transformation to {{bf{NO}}}_{{bf{3}}}^{{boldsymbol{-}}}-N, and inhibition of N2O and {{bf{NO}}}_{{bf{2}}}^{{boldsymbol{-}}} production. Compared with control, AP3 showed the highest inhibition of accumulated NH3 and N2O emission, by 57% and 24%, respectively, and with a 19% increase of total Kjeldahl nitrogen in the compost. The further pot experiment proved the application of the AP amendment compost could improve the yield and trace element nutrient accumulation in Chinese cabbage when planted in a typical Zn-deficient soil. This study illustrates that AP application benefits both compost nitrogen conservation and fertilizer quality.

Response of Hybrid Peach × Almond Trees to Increasing Rate of Soil-Applied Urea and Compost Nitrogen

ABSTRACTThe aims of the present study were to verify that high mineral N, specifically nitrate, may reduce plant growth by inducing a toxic effect on plants. GF667 plants were fertilized with urea or compost at rising rates of N (mg kg−1): 0, 200, 500, and 1000. At 8, 37, and 94 days after fertilization, plant growth, tissue N, root starch concentrations, electrolyte leakage (E. L.), superoxide dismutase (SOD), and catalase (CAT) enzymes were measured. Unlike compost, urea application promoted a linear increase of soil nitrate and ammonium during the experiment. Plant growth responded to urea-N application rates according to a second degree function with the highest plant biomass found at a urea-N rate between 200 and 500 mg N kg−1; and higher rates decreased plant growth. SOD and CAT showed no response to source and rate of N, while E. L. was higher in roots fertilized with urea-N.

Carbon sequestration in an intensively cultivated sandy loam soil in the North China Plain as affected by compost and inorganic fertilizer application

Understanding the balance between soil organic carbon (SOC) accumulation and depletion under different fertilization regimes is important for improving soil quality and crop productivity and for mitigating climate change. A long-term field experiment established in 1989 was used to monitor the influence of organic and inorganic fertilizers on the SOC stock in a soil depth of 0–60cm under an intensive wheat–maize cropping system in the North China Plain. The study involved seven treatments with four replicates: CM, compost; HCM, half compost nitrogen (N) plus half fertilizer N; NPK, fertilizer N, phosphorus (P), and potassium (K); NP, fertilizer N and P; NK, fertilizer N and K; PK, fertilizer P and K; and CK, control without fertilization. Soil samples were collected and analyzed for SOC content in the 0–20cm layer each year and in the 20–40cm and 40–60cm layers every five years. The SOC stock in the 0–60cm depth displayed a net decrease over 20years under treatments without fertilizer P or N, and in contrast, increased by proportions ranging from 3.7% to 31.1% under the addition of compost and fertilizer N and P. The stabilization rate of exogenous organic carbon (C) into SOC was only 1.5% in NPK-treated soil but amounted to 8.7% to 14.1% in compost-amended soils (CM and HCM). The total quantities of sequestered SOC were linearly related (P<0.01) to cumulative C inputs to the soil, and a critical input amount of 2.04MgCha−1yr−1 was found to be required to maintain the SOC stock level (zero change due to cropping). However, the organic C sequestration rate in the 0–60cm depth decreased from 0.41 to 0.29MgCha−1yr−1 for HCM and from 0.90 to 0.29MgCha−1yr−1 for CM from the period of 1989–1994 to the period of 2004–2009, indicating that the SOC stock was getting to saturation after the long-term application of compost. The estimated SOC saturation level in the 0–60cm depth for CM was 61.31MgCha−1, which was 1.52 and 1.14 times the levels for NPK and HCM, respectively. These results show that SOC sequestration in the North China Plain may mainly depend on the application of organic fertilizer. Furthermore, the SOC sequestration potential in the 0–20cm layer accounted for 40.3% to 44.6% of the total amount in the 0–60cm depth for NPK, HCM, and CM, indicating that the SOC sequestration potential would be underestimated using topsoil only and that improving the depth distribution may be a practical way to achieve C sequestration.

Influence of agricultural utilization of sludge and compost from rural wastewater treatment plant on nitrogen passes in light soil

Abstract This paper presents the results of studies which aim was to determine the pollution of the water environment for both methods of preparation for the utilization of sewage sludge in agriculture. The study was conducted in 2008-2012 in lysimeters filled with light sandy soil (clayey sand). During the study variants with equal doses of nitrogen in an amount of 20 g . m-2 (15.7 g per one lysimeter) were supplied to the soil in sewage sludge and in the compost made from the same sludge. These variants were used three times for two species of perennial plants: Miscanthus gigantenus i Sida hermaphrodita Rusby. In a variant of sludge soil fertilizing, it was leached into water environment more than 12% of the applied nitrogen over 5 years of research. In case of compost nitrogen leaching was reduced to 8.1-10.0% of the quantity supplied to the soil.

Nitrogen Dynamic and Microbiological Evolution During Aerobic Treatment of Digested Sludge

Anaerobic digestion produce considerable amount of digestates which may not meet the requirements for direct land spreading. Aerobic treatment provides an appropriate post-treatment method to deal with the increasing amount of digestates. In this work, we studied the nitrogen dynamic and the evolution of groups of microorganisms during aerobic treatment of digested sludge. The oxygen consumption concentrated in first 10 days which corresponded to the intense biodegradation of easily biodegradable materials. The mineralization of organic nitrogen in the digestates followed the intense biodegradation and contributed to considerable ammonia emissions. The ammonia oxidation flow decreased to around zero during the intense biodegradation phase and reestablished during the maturation phase. It contributed to the disappearance of ammonia emissions and a sharp decrease of stored ammoniacal nitrogen in compost. The low content of available carbon in the digestates probably limited the immobilization of ammoniacal nitrogen and the development of the total biomass of microorganisms. The number of ammonia-oxidizing bacteria decreased in first 5 days treatment but exhibited a significant development during the maturation phase. The development of ammonia-oxidizing archaea was not significant. Statistic correlation analysis indicates that the ammonia-oxidizing bacteria instead of the ammonia-oxidizing archaea were responsible for nitrification during the treatment of digested sludge (Sig. 0.01). Our results suggest that the length of composting process should be controlled to meet the needs of agriculture. It should ensure the consumption of excessive ammoniacal nitrogen but not reduce the fertilizer value of compost.

Process Conditions Influence on Pig Slaughter House Compost Quality Under Forced Aeration

The objective of this paper was to study the influence of process conditions (aeration rate, bulking agent (BA) particle size distribution, BA incorporation ratio and process duration) on the quality (moisture, stability, disinfection as per the temperature regime and nitrogen conservation) of mechanically aerated pig slaughterhouse sludge (PSS) compost. The waste and wood chips as BA were composted in 300 L mechanically aerated reactors. The range of process conditions tested were: aeration rate from 1.68 to 13.04 L/h/kg of wet sludge; BA particle size distribution of <10 mm, 10–20 mm and 20–30 mm, and; BA:PSS incorporation ratio of 0.55–1.11 (kg of wet wood chips/kg of wet sludge). The results showed that a high aeration rate and a high BA:PSS ratio produced a faster stabilization whereas BA of small particles size distribution increased the amount of biodegradable matter and slowed down stabilization. The composting temperature regime was positively correlated to O2 consumption with a high BA:PSS ratio and a small BA particles size. A low aeration rate, without being O2 limiting, optimized the composting process since too high or too low an aeration rate favored heat losses through respectively convection and water evaporation. Water loss was positively correlated with temperature regime and a higher BA:PSS ratio as opposed to a small BA particle size distribution. Similarly, medium to high aeration rates favored water removal. The composting process duration was reduced with a high aeration rates of 6.22 or 9.8 L/h/kg of wet sludge and a high BA:PSS ratio of 1.11. Finally, process condition had no influence on compost nitrogen conservation.

Yield of different white button strains in sugar cane by product-based composts

The production of quality compost for Agaricus bisporus using alternative and local agricultural wastes beyond the search for productive strains are among the main factors related to improve yield. Thus, we evaluated the effect of compost nitrogen supplementation type using two compost formulation based on sugar cane by-products such as straw and bagasse as raw materials: (1) classic compost using chicken manure and (2) synthetic compost using soybean bran, urea and ammonium sulfate, for the cultivation of the five strains of A. bisporus: ABI-05/03, ABI-04/02, ABI-06/05, and ABI-09/10 ABI-09/11. We found that the classic compost obtained average temperature and mass loss of 10.56 and 13.29% higher than the synthetic compost, respectively, during the composting, pasteurization and conditioning process. The classic compost achieved greater yield in the end of 25 days of harvest by the strains ABI-05/03, ABI-06/05 and ABI-04/02 corresponding to 26.78, 25.34 and 24.71%, respectively. We concluded that the classic and synthetic, based on sugar cane straw and bagasse are suitable agricultural waste for A. bisporus cultivation and the classic compost obtained higher composting temperatures in relation to synthetic compost, corroborating higher yields and more defined-pattern cultivation cycle for all strains when grown in classic compost. Key words: Agaricus bisporus, by-products, supplementation, classic, synthetic.