Evaluation of Soil Microbial Activity and Maize (Zea mays L.) Growth in Soil Amended with Composted Agroindustrial Wastes

The present study was performed to emphasize that tobacco waste compost can be used as an organic material resource in soils under semi-arid climate conditions. We determined soil microbial activity as well as the contents of the nutrition and the biomass of maize plant to indicate which compost is the most suitable one for decomposing by microorganisms in the soil. In the greenhouse experiment, the treatments consisted of tobacco waste compost (TWC), tobacco waste+olive pomace compost (TWOPC), tobacco waste+grape pomace compost (TWGPC), tobacco waste+ farmyard manure compost (TWFYC), inorganic fertilization (NPK) and control soil. Soil respiration was higher in TWC amended soils, followed by TWOPC, TWGPC and TWFYC amended soils compared to non-amended soils. The effect of compost applications on enzyme activity of soil was significant. The activities of protease, urease and dehydrogenase were significantly higher in the soil amended with TWC as compared to those of the other composts. Β-Glucosidase activity was highest (21 %) in TWOPC with respect to control soil. Aryl sulphatase activity in the soils amended with the composts increased between 20 to 26 % with respect to the control. Activity of alkaline phosphatase in soils amended with the composts was not different from the amount obtained for control soil. The maximum values of leaf N, K and biomass weight of maize plant were found in inorganic fertilizer treatment (NPK). The biomass weight increased 115 % and 83 %, respectively, in NPK and TWC treatments compared to the control soil. The results suggested that application of the composts including tobacco waste to soil at a rate of 30 t ha-1 increased the amounts of microbial activity, organic C, available P and K in soil. On the other hand, the amount of total N in the composts is not enough for the growth of maize plant.