Abstract

Climate change, a complex biophysical process is already happening. It is not possible to predict precise future climate conditions, but the scientific consensus is that global land and sea temperatures are warming under the influence of greenhouse gases, and will continue to warm regardless of human intervention for at least the next two decades (IPCC, 2007).This study comprised analyzing different treatments namely: (a) Soil only(S), (b) Compost and soil (SC), (c) Soil and Manure (SM), Soil and Manure(SM) and (e) Compost, Soil and Chemical fertilizers (SFC) for comparing greenhouse gas (GHG) emissions. The GHG emissions were monitored and compared by quantifying CO2 and CH4 fluxes using a static flux chamber. The following chemical and physical analyses of soil properties were monitored: pH, electrical conductivity, moisture content, bulk density, porosity, water holding capacity, volatile solids, Nitrogen, Phosphorus, Potassium and Total Organic Carbon (TOC). Further investigations involved analysis of crop yield and root system formation of Lactuca Sativa seedlings (lettuce) which were grown on the each treatment. The results showed that organic treatments such as MSW compost and chicken manure addition helped to maintain the pH of soil between 7.3-7.5 which is deemed conducive for vegetation. It was also deduced that both compost and chicken manure were successful in reducing the bulk density of the soil by at least 8 %. After 7 weeks, incorporation of compost triggered an increase of 135% in the TOC of the soil while the TOC of SM and SF increased by 108% and 86.9% only. A maximum flux of 46.41 g/m2/day of CO2 was measured from treatment SM on the 49th day. Thus, treatment SM acted as a source of CO2. Treatment SC was a sink for CO2, since the net fluxes of both CO2 and CH4 was zero. Application of fertilizer resulted in higher N2O emissions (31.98 kg N2O/yr) compared to compost application (25.86 kg N2O/yr) and chicken manure application (25.80 kg N2O/yr). The total greenhouse gas emissions from treatment SF, SC, SM, SFC were 10533, 8318, 25160 and 9805 kg CO2 equivalent/yr respectively. Compared to treatment SF, compost application reduced total GHG emissions by 21% while chicken litter increased GHG emissions by 139%. The number of leaves formed and height of shoots per plant were the highest in treatment SC and SM. The dry mass of Lactuca Sativa (Lettuce) from treatment SC was 10.9% compared to 10.3%, 10.5%, 10.1%, and 10.8% from treatments S, SM, SF and SFC respectively. The % crop yields of SC and SM was 100%. Treatments SF and SFC produced lower crop yields (75% and 65%) compared to the control, where the crop yield was 95%.