Author's Name:	M. A. Youssef & I. I. Sadek
Subject Area:	Life Sciences
Subject	Agricultural
Section	Research Paper

Soil CO2 emissions

As the atmospheric CO2 concentration continues to increase, more attention is being focused on the soil as a possible sink for atmospheric CO2. Fertilizer application to soil can play a vital role in influencing the losses of soil carbon by CO2 emission from the soil. This study was conducted to examine effect of different fertilization types on soil CO2 emissions. Emission of CO2 from wheat cultivated soil and fertilized with five different types of both organic and bio fertilizers were measured during seasons of 2011/2012 and 2012/2013, comparing with the emission in case of using chemical fertilizers at experimental farm and laboratory of Soils and Water Sci. Dept., Fac. of Agric., AL-Azhar Univ., Assiut, Egypt. Tested fertilizers were 150 L/fed., compost tea, 20 L/fed., K-Humate, 10 L/fed., EM, 150 L/fed., compost tea + 10 L/fed., EM, 20 L/fed., K-Humate + 10 L/fed., EM and common chemical fertilizers (NPK). Amount of CO2 emission were measured frequently every 30 days after sowing date (30, 60, 90, 120 and 150 days) and total accumulated CO2. Moreover, Soil properties as available nitrogen (AN), soil organic matter (SOM), soil pH content and yield and its components were determined. Results indicate that, the highest values of "AN" and "SOM" were recorded with compost tea + EM, while, the lowest values were obtained with chemical treatment. Chemical treatment increased soil pH more than other treatments except K-Humate and K-Humate + EM treatments. The compost tea + EM treatment gave the high reduction value of pH, while, control, K-Humate and K-Humate + EM treatments gave highest values without any significant between them. The greatest values of yield and its components were from applied compost tea + EM treatment. Meanwhile, the lowest values of tested parameters were recorded with added EM treatment. The lowest emission was taken by using compost tea + EM. While, the soil CO2 emission was increased with added K-Humate + EM. In addition, amount of emission from soil was increased by the time to reach the peak after 120 days from sowing date. Furthermore, indicated that, the average air temperature, minimum air temperature, maximum air temperature and average soil temperature, respectively, had significant exponential relationship regression during the entire measuring period of CO2 emission.