An investigation of composting in optimal, nitrogen-poor and carbon-poor conditions

Abstract

Composting is based on a natural process that results from the decomposition of organic matter by microorganisms. Decomposition occurs wherever organic matter is provided with enough oxygen and moisture. The control of other parameters such as temperature, C/N ratio and pH, help to optimize the decomposition process. Compost-making has a twofold objective: producing a final product that is useful in our soils as well as reusing some of the waste produced by human activities. This project briefly investigates the biology involved in the composting process. Three wooden homemade compost bins were prepared, in which were put a range of different materials, including kitchen waste, dry and fresh leaves from trees, and woody garden waste for a period of three summer months. In this investigation, the conditions of the three compost bins were manipulated in order to produce an optimal, a carbon poor and a nitrogen poor type of compost. The suitability of the three kinds of compost produced was also assessed using germination of radish seeds as an indicator. Furthermore a survey of opinions regarding compost-making was carried out through a questionnaire. Following a review of the main factors that are necessary for good composting, the methods used are described, including the construction of the bins, the actions taken, the observations made during the composting process and the survey methods involving the questionnaire. The experiment involving radish seed germination has proved the usefulness and potential benefits of compost into the soil. The nitrogen poor type of compost trays had the highest recorded number of radish plants, followed by the optimal type of compost trays. In the carbon poor type of compost trays, the rate of plant growth was almost zero while the 50:50 mix of carbon poor type of compost with soil gave better results. But still, the amounts of nutrients available in the three different composts produced in my experiment, had supplied more nutrients to the radish plants than in those that were grown in soil only. Only one plant has survived from the four that have grown in my two soil trays.