A pot experiment was carried out using pots receiving 6kg cal-careous soil; half, same or double recommended dose of either aerobic or anaerobic compost of sugarbeet residues was used. The used corn-post was one of three composting periods: 3, 6 and 9 months. Wheat was the first crop to be planted up to maturity to study the direct ef-fect of the compost. Sudangrass followed wheat to study the residual effect of the compost. Three successive cuts were taken from the su-dangrass. Results abstained could be summarized in the following: - Organic matter content in soil decreased with time of application. - The soil which received aerobic compost contained organic matter higher than that received anaerobic one. - Period of composting 6 months was the best under aerobic conditions but in case of anaerobic composting 9 months period was the superi-or. - Increasing dose of application increased proportionally soil organic matter content. - Total nitrogen also increased by time of composting: the most superi-or treatment was addition of 4% compost having 6 months compost-ing period under aerobic condition, while the best treatment of anaero-bic compost being of 4% of the 9 months composted one. These results were the same for soil samples taken either after wheat or following sudangrass. C/N ratio was wider after harvesting su-dangrass than that after wheat. This was due to the consumption of ni-trogen by sudangrass plants, the ratio narrowed by increasing the dose of compost particularly under aerobic conditions. Available phosphorus and potassium increased by increasing the dose of application. The best period of composting was 6 months for aerobic and 9 months for anaer-obic conditions.