A study was conducted to determine the effects of short- and long-term application of organic manure on soil chemical properties including soil pH, EC, CaCO₃, SOC, and soil available N and P under arid conditions. The solid and liquid organic manure were applied to the soils cropped with the vegetable for either up to 2-years under vegetable plants or 15-years to soils cropped with fruit trees. Soil samples were collected at sampling depths of 0-15, 15-30, 30-45, 45-60 cm. Results showed that the soil organic carbon (SOC) content ranged between 0.6-12 g kg^-1 and 1.7-31.5 g kg^-1 after organic manure application for one year and 15-years in soil samples cropped with fruit trees, respectively. Moreover, SOC content ranged between 0.6 and 6.4 g kg-1 and 0.9 and 8.6 g kg^-1 after organic manure application for the one year and 2-years in soil samples cropped with vegetable, respectively. The highest soil available N (211 mg kg^-1) was found after long term application of organic manure (15-years) followed by that (162 mg kg^-1) found after the 2-years organic manure application. The higher soil available P (52-60.2 mg kg^-1) was also found with 15-years and 2-years application of organic manure. It could be concluded that the addition of organic manure to the soil of arid condition may be suitable for maintaining soil organic carbon and improving soil fertility by increasing N and P availability.