In recent years, many attentions have been focused on determination of soil biological properties. The standard procedures for determination of soil biological properties are well developed however; to be routinely used in the soil laboratories, there are some discrepancies. Therefore many efforts have been spent to develop alternative, simple and rapid procedures providing similar accuracy and precision. The newly developed procedures are usually less time consuming, labor intensive and provide less exposure to toxic chemicals. Microwave irradiation has been used as an alternate energy source for many experimental procedures. This source of energy can facilitate some soil biological assays. The objectives of this study were to identify whether the microwave irradiation can be used as an alternative to 1) the chloroform fumigation in soil microbial biomass determination 2) the autoclave-assisted digestion of soluble organic N in soil extracts and 3) the prolonged incubations usually perform in N mineralization potential. For these purposes, 29 soil samples were collected from different climatic regions of Iran . General soil properties including pH, ECe, organic C, calcium carbonate equivalent and soil textures were determined. Soil microbial biomass N was measured by either chloroform fumigation-extraction (CFE) or microwave irradiation-extraction (MWE) techniques. The soluble organic N in the soil extracts were measured by both alkaline-persulfate and microwave-assisted oxidation. Potentially mineralizable N was also measured either by anaerobic incubation or by a microwave-based technique. Results indicated that at 50% (w/w) water content, 1200 j g -1 soil can eradicate microbial activities without disturbing soil humic material. Following optimization of the microwave irradiation, a significant (r=0.72, P 0.01) correlation was observed between the values of soil microbial biomass N measured by CFE and MWE techniques, suggesting that both techniques have determined similar pools of soil N. In order to determine soluble organic N in the soil extracts, we observed that 2:1 reagent: sample ratio along with 800 j g -1 irradiation in two equal 400 j g -1 bursts can provide highly significant correlation (r = 0.9, P 0.001) and identical results, compared to the standard alkaline-persulfate oxidation procedure