Ratio Of Compost Research Articles

A kinetic study on how C/N ratio affects energy consumption of composting of rose oil‐processing wastes with caged layer manure and straw

Composting process parameters such as C/N ratio, moisture content, and temperature are well studied, but limited knowledge exists on energy consumption of the process itself. In this study, co‐composting of rose oil‐processing wastes (ROPW) with caged layer manure and straw was performed to optimize the system in terms of energy use. Intermittent aeration applied to the five compost mixtures with initial C/N ratios of 12.81, 21.37, 24.66, 29.22, and 37.41 was conducted using fifteen identical cylindrical reactors with volume of 60 L. O2 and CO2 concentrations, compost temperature, dry matter loss, organic matter loss, electrical conductivity, and pH were measured. A first‐order kinetic model based on material mass balance was applied to determine kinetic parameters such as decomposition rate and compost equilibrium mass. An equation describing specific energy per initial dry mass of composting as a function of initial C/N ratio was presented and used to optimize initial C/N ratio to maximize composting of ROPW to reach a given level of compost mass ratio. The maximum decomposition, based on dry matter loss, occurred at the initial C/N ratio of 30.18 was 0.032 kg kg−1 day−1. Initial C/N ratio to minimize specific energy use of ROPW composting with caged layer to reach a given level of compost ratio of 0.82 was 29.11. Composting operation can be performed at this initial C/N ratio (29.11) to minimize airflow to keep the power requirement low while still operating the system efficiently. This helps to reduce the energy required for ROPW composting with caged layer to reach a given compost mass ratio. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 129–137, 2017

Waste recycling by vermicomposting: Maturity and quality assessment via dehydrogenase enzyme activity, lignin, water soluble carbon, nitrogen, phosphorous and other indicators

Present study aims to examine the dynamics of maturation and qualification indicators in various vermicompost treatments and selection of the best treatment along with best maturation time in this regard. In this empirical study, dynamics of chemical (pH, electrical conductivity (EC), total nitrogen (TN), phosphorous, lignin, water soluble carbon (WSC), C/N, NH4/NO3) and biological (dehydrogenase enzyme (DEH) and DEH/WSC) properties were investigated in four various treatments, including various ratios of compost produced from municipal solid waste (MSW) and carbonaceous materials (50:50, 70:30, 85:15 and 100:0) over 100 days.Results showed a significant fluctuation in EC, DEH and DEH/WSC proportions over the process. In addition, a noticeable increase was observed for the dynamics of TN, phosphorous and lignin. In contrast, the C/N, NH4/NO3 and WSC values gradually decreased during the process. Moreover, it was observed that the length of 75 days for the process is an appropriate time for maturation of all treatments. However, the first and second treatments resulted in better outcomes compared with the other types of treatments. From the point of view of quality obtained vermicompost was nitrogen enriched product in all treatments. Whereas, for the phosphorous elements this method is appropriate for the first treatment only.

Crescimento e balanço nutricional de mudas de Enterolobium contortsiliquum com aplicação de substratos orgânicos e água residuária

Diante da geração acentuada de resíduos orgânicos sólidos e efluentes, a utilização desses materiais como fonte primária de nutrientes consiste em uma importante prática de gestão ambiental, sobretudo na produção de mudas com ênfase à recuperação de áreas degradadas. Objetivou-se com este trabalho avaliar o crescimento e o balanço nutricional de mudas de tamboril (Enterolobium contortsiliquum (Vell.) Morong) cultivadas em substratos com diferentes formulações e proporções de resíduos orgânicos irrigados com água residuária. Foram testados cinco proporções de composto orgânico e solo: 0:100; 20:80; 40:60; 60:40 e 80:20 v/v, e duas qualidades de água de irrigação: água de abastecimento e água residuária de suinocultura, dispostos em delineamento inteiramente casualizado em esquema fatorial, 5 x 2, com quatro repetições. Aos 90 dias, foram avaliadas as variáveis morfológicas, índices do sistema integrado de diagnose e recomendação e do balanço nutricional médio das mudas. Constatou-se que o resíduo orgânico contribui para o crescimento e o equilíbrio nutricional das mudas. A proporção 80:20 mostrou-se a mais indicada à produção de mudas de tamboril. O crescimento e balanço nutricional das mudas foram inferiores nos tratamentos que receberam irrigação com água residuária de suinocultura.Growth and nutrient balance of Enterolobium contortsiliquum seedlings with addition of organic substrates and wastewaterGiven the strong generation of solid organic waste and wastewater, the use of these materials as a primary source of nutrients is an important practice in environmental management, especially in the production of seedlings with emphasis on degraded areas. The objective of this study was to evaluate growth and nutrient balance of “tamboril” (Enterolobium contortsiliquum (Vell.) Morong) seedlings grown on substrates with different formulations proportions of organic matter irrigated with wastewater. It was tested five ratios of organic composts and soil: 0:100; 20:80; 40:60; 60:40 and 80:20 v/v. Two procedences of irrigation water was tested: water supply and wastewater from swine farming, arranged in a completely randomized design in a factorial scheme 5 x 2, with four replications. At 90 days, we evaluate seedlings morphological variables, the integrate diagnosis recommendation index and the nutrient balance index. The organic residue contributes to seedlings growth and nutritional balance. The proportion 80:20 proved to be the most suitable for “tamboril” seedlings production. Seedlings presented lower growth and nutritional balance when irrigate with swine farm wastewater.Index terms: “Bagana de carnaúba”; Bed aviary; Swine wastewater

Effect of Composition on Basic Properties of Engineered Media for Living Roofs and Bioretention

AbstractEngineered media used in living roofs and bioretention plays a crucial role in determining stormwater mitigation performance. Engineered media with compositions varying in four aggregates, volumetric ratio of compost (0, 10, and 20%) and three amendments (zeolite, paving sand, and topsoil) were prepared in the laboratory. Media basic properties including particle-size distribution (PSD), dry bulk density, particle density, porosity, and saturated hydraulic conductivity (Ks), were characterized and investigated as a function of the varying composition. All media are classified as poorly-graded sand (SP), exhibiting porosity greater than 0.51, with magnitudes of Ks ranging from 10−2 to 10−1 cm/s. Media with pumice-based aggregates have particle densities between 2.21 and 2.48 g/cm3. The Ks of a pure aggregate classified as SP is positively related to the particle size corresponding to 50% fines on the cumulative PSD curve. Ks values of four aggregates either remain unchanged or decrease by 73% at ...

Co-composting of organic solid waste and sewage sludge – a waste management option for University Campus

Co-composting organic solid waste with dewatered sewage sludge was carried out to determine its suitability for managing waste on a University campus. Windrow composting method was employed in which dewatered sewage sludge and organic solid waste were mixed at volume ratios: 1:1, 1:2, 1:3, 0:1 and 1:0 sludge/organic solid waste. Parameters such as pH, percentage N, C, P, K, Ca, Mg, organic matter, ash content and C/N ratio were determined weekly. Total and faecal coliform population were measured biweekly with Pb and Cd levels determined at the beginning and end of the composting. With the exception of ratio 1:0 sludge/organic solid waste, all other ratios attained a favourable Carbon to Nitrogen (C/N) ratio both at the start and end of the composting process. Levels of major nutrients measured were found to be favourable for use as organic fertilizer. There was a general decline in carbon and organic matter in all the compost piles except the sewage sludge pile (1:0). Apart from the compost ratio 1:0 sludge/organic solid waste, all other ratios attained a temperature of 55°C within 8 days of composting. Generally the compost ratios 1:2, 1:3 and 0:1 (sludge/organic solid waste) were found to be the most suitable for use as organic fertilizer. International Journal of Environment Vol. 5 (1) 2016, pp: 14-31

English

According to limited water in arid regions and its sharp drop per capita, we have to maximize water use efficiency under the best system for saving water (drip irrigation). To achieve this goal, two field experiments were carried out during growing seasons 2013 and 2014, it was executed in research farm of national research center (NRC) in Nubaryia province, Egypt, to study the effect of new engineering method for irregular volumetric distribution ratios of compost under reduction of emission uniformity on yield and water use efficiency of peanut crop. Study factors were irregular volumetric distribution ratios of compost on four zones along lateral were [D1= (25%, 25%, 25%, 25% compost), D2= (20%, 20%, 25%, 35% compost), D3= (15%, 15%, 30%, 40 compost) and D4= (10%, 10%, 35%, 45% compost)] under reduction of emission uniformity (EU) and emitter discharge along lateral, [EU1= 90%, EU2 = 80%, and EU3 = 70%].to study the effect of new engineering method for irregular volumetric distribution ratios of compost under reduction of emission uniformity on yield and water use efficiency of peanut crop. The following parameters were studied to evaluate the effect of study factors on: (1) Application efficiency along lateral. (2) Water stress along lateral (3) Yield of peanut, (4) Irrigation water use efficiency of Peanut IWUE Peanut.

Suitable Maturity Stage, Type of Cuttings and Potting Media for Vegetative Propagation of Pogostemon heyneanus Benth

Pogostemon heyneanus Benth. (Lamiaceae) is an industrially important aromatic crop extensively cultivated in Asian countries as the main ingredient of perfume, high valued cosmetic and an array of ayurvedic products. Eventhogh it has high potential as an industrial crop, commercial cultivation in Sri Lanka is hampered due to lack of authentic, superior quality planting materials and optimized protocol for mass propagation of P. heyneanus. Therefore, in the present study an attempt has been made to investigate the optimum protocol for mass propagation of authentic, superior quality variety of P. heyneanus in order to ensure the commercial scale cultivation in Sri Lanka. Two types of cuttings (single and double nodal) at three maturity stages (i.e. softwood, semi-hardwood and hardwood) were obtained from healthy mother plants and planted in poly bags filled with top soil: sand: compost ratios of 1:1:1, 1:1:2 and 1:2:1. Number of leaves, number of branches, length of branches, height and the spreading of plants were recorded at 2 weeks intervals. Data were analysed and the highest plant height (52.9 ± 2.1 cm), length of branches (82.2 ± 5.6 cm), number of leaves (32.3 ± 2.6), number of branches (4.6 ± 1.5) and spreading of plant canopy (28.5 ± 1.7 cm) were observed in hardwood double nodal cuttings planted in potting medium 1:1:1 ratio. It is thus suggested to use hardwood double nodal cuttings as planting material and top soil 1: sand 1: compost 1 as potting medium for propagation of P. heyneanus in commercial scale cultivation.

PEMANFATAN DAUN TEBU KERING (DADHOK) DENGAN PENAMBAHANBLOTONG DAN AKTIVATOR EM4 UNTUK PEMBUATAN KOMPOSDI KECAMATAN KREMBUNG KABUPATEN SIDOARJO TAHUN 2015

Dry sugarcane leaves (dadhok) are garbages of sugar cane harvest that have not been managedproperly. One of the alternatives to reduce pollution generated is to use it as compost. This studyaims to determine content of dry sugarcane leaves as compost with the addition of blotong andEM4 activator.This research uses experimental design with Pre-Post Test Only Design. There were fourexperiments conducted within the study: 1st experiment was dry sugarcane leaves (control), 2experiment was dry sugarcane leaves + EM4 activator, 3blotong, 4thrd experiment was dry sugar cane leaves + experiment was dry sugar cane leaves + EM4 activator + blotong. Data was collectionby measurement and laboratory testing. Data was then analyzed descriptively by referring to theRegulation of the Minister of Agriculture numbers 70 / Permentan / SR.140 / 10/2011 and SNI 197030-2004.Resultshows that of the four experiments conducted, C / N ratio of compost that met the requirement was the 2nd, 3rd, and 4th experiment but only the 3ripe compost requirement (color, texture, smell). Compost of 2ndrd and the 4th experiments fulfilled experiment was not perfectly ripefor EM4 only reduce the value of C / N ratio but it cannot degrade the material. On experiment 1,C / N ratio and compost ripeness did not meet the requirement. Macronutrients of all experimentsdid not meet the requirement. This was because the raw material had low macronutrients.Findings conclude that only the 3rd and the 4th experiments meet the requirement of PermentanRegulation number 70 / Permentan / SR.140 / 10/2011 and SNI 19-7030-200. Experiment 1 and 2were not qualified. Findings suggest sugar mills to distribute the abundant waste of blotong tofarmers that it can be used with dry sugarcane leaves as compost. For community who possessugar cane plantations, sugarcane leaves can be used as compost that they can use it to increasetheir income.

Effects of microbial inoculation on composting of household organic waste using passive aeration bin

BackgroundThe effects of microbial inoculation with two commercial inoculants and mature compost on the composting of household organic wastes were investigated using five 200-L passive aeration compost bins. Food scraps and dry leaves (1.6 kg total) with a ratio of 1:0.14 (wet weight) were added to each bin once a day, for 60 days, and then further composted for an additional 94 days. The temperature in each bin was recorded daily. Weekly to biweekly, a composite sample of the compost from each bin was analyzed.ResultsThe C/N ratios of composts in the un-seeded and seeded bins stabilized at 81 days and 67–74 days, respectively. The highest volatile solid mass reduction was achieved in the bin seeded with 5 % mature compost.ConclusionsThe study revealed that it might not be necessary to add commercial inoculants to facilitate composting of household organic waste. Mature compost can be used as a seed starter to improve composting.

Measurement of the maximum amount of water-extractable phosphorus in animal manure compost by continuous and sequential water extraction

Measuring the phosphorus (P) solubility in animal manure compost (AMC) is important to estimate both the risk of P loss from agricultural land and the P availability for crops in agriculture that use AMC as fertilizer. Water-extractable phosphorus (WEP) has most often been used to estimate P solubility in AMC. A single water extraction with a high ratio of compost to water is usually used to determine WEP, but in many cases, this may not evaluate the maximum WEP. In this study, we extracted the P included in AMC by using a continuous extraction method with a large amount of water, and tested this approach for 16 AMCs: four cattle manure composts, five swine manure composts, five layer (chicken) manure composts, and two broiler (chicken) litter composts. The P dissolution patterns were fitted to kinetic models, and the maximum WEP (WEPmax) was determined by the coefficient of the non-linear regression equation. The WEPmax values corresponded to the sum of H2O- and sodium bicarbonate (NaHCO3)-extractable P measured using the modified Hedley sequential extraction method. The result also suggests that the maximum amount of WEP from AMC can be estimated rapidly using a sequential extraction (the Hedley method) that has been widely used to characterize P in manure or AMC. The maximum water-extractable magnesium (Mg) (WEMgmax) was significantly positively correlated with WEPmax (r = 0.854, P < 0.01). This suggests that WEPmax in the AMCs is affected by water-soluble magnesium compounds.

English

Physical, chemical and biological parameters were optimized during composting to enhance degradation of oil sludge. Mixtures of oil sludge, garden soil, poultry manure and the bulking agents were co-composted in static piles of about 1 m3 on wooden pallets overlaid with nylon fibre sheets. Temperature, moisture, electrical conductivity (EC), pH, total carbon, total N, heterotrophs and respiration of compost microorganisms were monitored in each pile. Moisture was maintained at between 60 and 70% field capacity. Temperatures reached a mean of 63&deg;C in the compost containing manure and sawdust. The C:N ratio of composts changed significantly during the composting process, reaching 100:41 (sawdust+manure) 100:39 (hay+manure) and 100:31 (woodchips+manure). Respiration of compost organisms rose from 1490 to 3850 CO2 (&micro;g)/dwt/day in the sawdust+manure compost. Total petroleum hydrocarbons (TPH) decreased by between 52 and 66% in the composts and concentrations of selected polycyclic aromatic hydrocarbons (PAH) by between 78 and 100%. The Bacillus, Pseudomonas, Arthrobacter and Staphylococcus species were predominant in all the experiments and all temperature regimes. &nbsp; Key words: Bulking agents, compost bioremediation, crude oil sludge, microorganism, polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH).

EVALUATION OF PHYSICAL, CHEMICAL, BIOCHEMICAL AND PHYTOTOXICITY OF TUNISIAN MATURE AGRICULTURAL WASTES AS COMPOSTS

In this study six final products of co-composting were evaluated by comparing the changes in physical, chemical and biochemical properties and phytotoxicity of different mature composts. These were obtained by composting agricultural wastes (almond and sesame shells, olive husk, olive mill waste water sludge, poultry manure, green and wood wastes) for eighteen months. The studied composts were character-ized by basic pH, mostly over pH 9, and an EC value ranging from 1.6 to 3.6 mS/cm. Organic matter (OM) and C/N ratio of composts ranged from 20% to 46% and 10% to 21% respectively. The biological stability of composts was evaluated by measuring cellulose, hemicelluloses, and lignin and Weende cellulose contents as well as by calculating Biological Stability Index (BSI). The BSI ranged from 0.13 to 1.31. Phytotoxicity of composts was studied by determining cress seed germination in mixtures of relative compost and peat. The variation in properties is related to the nature of used agricultural wastes. Some of these properties are compatible with using composts as components in substrates for horticultural and soilless culture: other are compatible with composts as soil fertilisers.

Domestic Organic Waste Composting in Madhyapur Thimi, Bhaktapur

Organic waste composting is an important waste management practice that can reduce the volume of municipal solid waste and increase crop productivity. A study was carried out in Madhyapur Thimi, Bhaktapur in order to develop understanding of different methods of composting for sustainable solid waste management practices. Solid waste was collected randomly from 50 households in the area and segregated manually. The biodegradable waste was composted through pile (aerobic), aerobic bin, anaerobic (pit) and vermicomposting process. The physico-chemical and microbial analysis of composts were carried out in laboratory whereas significance of composts on crop productivity was tested in the study area. The study showed that 81.4% of the waste generated was biodegradable. The physico-chemical and microbial analyses of the compost samples showed pH range of 7.6 to 8.2 and moisture content of 54.5% to 69.5% for different composts. The maximum temperature (62°C) was observed in aerobic (pile) composting. The nutrient analysis (oganic matter, nitrogen, phosphorus, potassium and C: N ratio) of different composts showed that vermicompost was the most among all the composts. The total bacterial and fungal count varied from 3.91 x 104 to 8.05 x 106 cfu/g and 1.30 x 103 to 3.25 x 104 cfu/g respectively. The vermicompost was found rich in microbial population too. The application of vermicompost at 6.25 mt/ha in the study area resulted in increasing in height, diameter and yield of cauliflower by 15.62%, 37.58% and 38.95% respectively over farm yard manure. The height, diameter and yield of cauliflower grown in different composts was found to be significantly different (P&lt;0.05). Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 129-136 DOI: http://dx.doi.org/10.3126/njst.v14i1.8933

Field scale ex-situ bioremediation of petroleum contaminated soil under cold climate conditions

Assessment and development of strategies for ex-situ bioremediation in cold climates, such as in Canada, is of great importance for decontamination of contaminated soils. The purpose of this paper was to evaluate and compare the use of microbial consortia inoculant and mature organic compost as bioaugmentation and biostimulation strategies to enhance ex-situ bioremediation of a soil contaminated with heating oil under cold weather conditions. The soil was impacted as a result of leakage from an above-ground storage tank and had an initial TPH concentration was 940+ 127 μg g−1 (dry weight). Aerobic biopiles of 16 m3 each were constructed and subjected at a field scale to microbial consortia inoculant and 10:1 ratio of mature organic compost. Two biopiles (S) contained only soil as control, two biopiles (S + C) contained soil and compost to assess the individual effect of compost addition, two biopiles (S + M) contained soil and microbial consortium to assess the individual effect of microbial consortium addition, and three biopiles (S + C + M) contained soil plus compost and microbial consortium to assess the combined effect of compost and microbial consortium addition. Over a 94 days period, composite soil samples for each biopile were collected and analysed for total petroleum hydrocarbons (TPHs), volatiles (F1), semi volatiles (F2) and non-volatiles (F3) fractions, microbial counting, and pH. Additionally, field measurements including soil temperature, moisture content, carbon dioxide (CO2) and oxygen (O2) were carried out. Although the ambient temperature varied from −3.5 °C to −24.1 °C, the internal soil temperatures for the different experimental setups maintained above freezing conditions. Results showed that biocell inoculated with microbial consortia and amended with 10:1 soil to compost ratio under aerobic conditions performed the best, degrading 82% of total petroleum hydrocarbons (TPHs) with a first-order kinetic degradation rate of 0.016 d−1, in cold weather conditions. The average removal efficiencies for TPHs after 94 days for S, S + M, S + C treatments were 48%, 55%, and 52%, respectively. Statistical analysis indicated significant difference (p < 0.05) within and between the final measurements for TPHs and significant difference between the treatment with combined effect (S + C + M) and the control (S) as well as individual treatments of S + C and S + M. The study concluded that the combination of microbial consortia inoculation and mature compost as a biostimulant in a 10:1 soil to compost ratio would be an appropriate bioremediation approach for this type of soil matrix, reaching values below provincial standard regulations in just 40 days after construction. This research aimed to provide valuable knowledge to practitioners about cost-effective and existing strategies for ex-situ bioremediation during cold weather conditions.

Positive effects of composted biochar on plant growth and soil fertility

Mankind is actually facing serious issues due to the overexploitation of fossil fuels, biomass, soils, nitrogen, and phosphorus. It is claimed that biochar addition to soil improves C sequestration to prevent CO2 from atmospheric cycling. Biochar addition should also increase soil fertility in a similar way as anthropogenic dark earths of Central Amazonia. Previous studies have shown that biochar stimulates plant growth and increase fertilizer efficiency, especially when biochar is combined with organic fertilizers such as compost. However, little is known about optimum addition amounts and mixture ratios of biochar and compost. Indeed most experiments to mimic Terra preta de Indio focused on biochar alone or biochar in combination with mineral fertilizers. Therefore, we studied optimum biochar and compost amounts and mixture ratios with respect to plant response and soil fertility. We tested the effect of total amount from 0 to 200 Mg/ha, and biochar proportion from 0 % to 50 % biochar, of 18 different compost mixtures on growth of oat (Avena sativa L.) and soil properties in a fully randomized greenhouse study with sandy and loamy soil substrates. We sampled soil substrates before and after plant growth and analyzed plant growth and yield, total organic carbon (TOC), total nitrogen (TN), mineralized nitrogen (Nmin), soil reaction (pH), and electrical conductivity (EC) applying standard procedures. Results show that biomass production was increased with rising biochar and compost amounts. Oat plant height and seed weight was improved only with rising biochar amounts, but not with compost amounts. This could be explained by increase of total organic C and total N but not by plant-available ammonium and nitrate. The positive influence of composted biochar on plant growth and soil properties suggests that composting is a good way to overcome biochar’s inherent nutrient deficiency, making it a suitable technique helping to refine farm-scale nutrient cycles.

Windrow Composting of Waste Sugar Cane and Press Mud Mixtures

Compost made from mixtures of sugarcane byproducts bagasse and press mud are produced in several countries. In this work experimental results are presented for composting trials in which bagasse was substituted with waste sugarcane in the mixture with press mud. A trial was carried out in large scale windrows mechanically turned. Three mixture piles and one pile for each raw material were processed in 140 days. Substituting cane bagasse as bulking agent for waste whole sugarcane did not introduce significant changes in the composting process which proceeded smoothly. The losses in organic matter ranged from 64 to 72 %. The C/N ratio of mature composts was between 10 and 20. No signs of phytotoxicity were observed with black bean seeds which germinated between 95 and 100 %. A greenhouse experiment employing tomato seeds showed that compost made from waste sugarcane could be mixed with soil up to 50–60 % where tomato plant height and weight were at their maximum value.

Organic fertilization: An alternative to produce jalapeñ o pepper under greenhouse conditions

The experiment was conducted during fall-winter seasons of years 2011-2012 to determine the effects of vermicompost tea (VCT) on growth and productivity of ?Hechicero? jalapen o pepper plants grown under organic and synthetic fertilization in greenhouse. Five different fertilization forms were applied to plants [F1 = sand + inorganic nutrient solution (control group); F2 = sand + VCT on concentration of 10%; F3 = mixture of sand + compost (ratio 1:1; v:v) + VCT on concentration of 2.5%; F4 = mixture of sand + vermicompost (ratio 1:1; v:v) + VCT on concentration of 2.5% y F5 = mixture of sand + compost + vermicompost (ratio 2:1:1; v:v:v) + VCT on concentration of 2.5%]. Treatments F4 and F5 showed an increased yield of 70 and 45% with regard to the yield obtained with F1; the F1 and F2 yields were not statistically different at the 0.05 significance level. The fruit length and the pericarp thickness were increased until 7.55 and 7.01% in F5, respectively. These results suggest that, since there were differences in yield when using the organic and inorganic nutrient source VCT combined with mixtures of sand + compost + vermicompost may be considered a successful alternative fertilizer for organic jalapen o pepper production in greenhouse.

Effects of compost application on soil fertility of a Luvisol from Gödöllő (Hungary)

The effect of compost application on the chemical soil properties, which are important for soil fertility, was analysed. Pot experiments were set up before and after incubation of soil mixed with compost. Four treatments include 0, 2.5, 5 and 10 m/m % compost mixed to soil were used; each treatment was repeated four times. Compost was from plant residues, and soil (Luvisol) from agricultural land of Gödöllő. Ryegrass (Lolium perenne) was seeded in the pots. The pots were set up at standard 20°C in a climate room, irrigated daily to 60% of field capacity, and cut after three and four weeks. During the incubation monthly, the hot water percolation-soluble C and N content was analysed. After cutting the ryegrass, plant weight was measured and N, P and K content of plants was analysed. Soils with higher compost ratio show a higher C, N P and K content. The plant analysis for both the not incubated and soils incubated with different compost portions show the following differences: fresh and dry plant weight and N, P and K content of the treatment with 10 m/m % compost increased significantly. Hot-water-soluble N content increased continuously during the six months of incubation, while C content decreased.

Evaluation of Growth Media Incorporating Cotton Ginning By-products for Vegetable Production

The suitability of by-products from the cotton ginning industry for incorporation into growth media for three vegetable crops was examined. Composts were prepared by mixing the by-product with soil in 5 ratios (20:80, 40:60, 60:40, 80:20, 100:0, v/v compost and soil). Seeds of lettuce (Lactuca sativa L.), radish (Raphanus sativus L.) and spinach (Spinacia oleraceae L.) were sown directly within the composts and in 100% peat (control) in October (autumn crop) and December (winter crop). Plant growth (height, leaf number, dry and fresh weight, chlorophyll content) was recorded 19 and 17 days after transplantation (first and second sowing respectively) and at harvest. Fresh and dry weight was recorded at harvest. Overall, plant height and leaf number were higher when the growth media consisted principally of compost (higher ratios of cotton by-product: soil) than in the control (peat), whereas among the various ratios of compost: soil significant differences were recorded, media with a high compost content showing better growth in most cases. Similar results were reported for fresh and dry weight and chlorophyll content, except for dry weight in the second sowing, where growth media with a lower compost content had a higher dry weight. In conclusion, the incorporation of the cotton ginning by-product into compost resulted in better growth of lettuce, spinach and radish, suggesting that the use of this material may be of economical value as a spin-off product for the cotton ginning plant and also as a means of reducing present pollution of the environment due to the accumulation of waste material.

Evaluation of Compost Maturity, Hydrophysical and Physicochemical Properties: Indicators for Use as a Component of Growing Media

The cocomposting of agricultural waste is a new management priority in Tunisia. In this study, four composts were evaluated by comparing the changes in measured hydrophysical and physicochemical properties and phytotoxicity. The organic wastes used were almond shell (AS), sesame bark (SB), olive husk (OH), and green and wood wastes (GW and WW, respectively). Composts CI and CII were composed of AS/SB and OH/SB, respectively, at a ratio of 75/25 (wet weight basis). CIII consisted of OH, SB and CAS (coarsely-ground almond shell used as a bulking agent) at a ratio of 55/25/20. Finally, CIV was composed of 25%SB+9%CAS+18%GW+48%WW. The composts studied were characterized by basic pH and an electric conductivity (EC) value ranging from 1.6 to 2.4 mS/cm. The organic matter contents (OM) and C/N ratios of composts ranged from 20 to 46% and from 10 to 21%, respectively. Based on hydrophysical analyses, composts CI, CIII and CIV, containing AS, were shown to have a porosity and a water content of 10-26% and 10-20%, respectively. The phytotoxicity of composts was studied on the basis of cress seed germination. Results revealed that differences in properties are mainly related to the nature of composted waste and that some of these composts are compatible for use as constituents in growing media for horticultural soilless cultures.