Investigations were carried out on the temporal variations in organic carbon and nutrient availability in arid zone agroforestry systems. Organic carbon, extractable P, NO3-N and NH4-N were determined in top 20 cm soil layer under three year old agroforestry systems comprising Emblica officinalis Gaertn., Hardwickia binata Roxb. and Colophosper-mum mopane (Kirk ex Benth.) Kirk ex J. Leonard tree species with Vigna radiata (L.) as inter-crop and a control. The temporal variations in soil organic carbon (SOC) (P<0.01), extractable P (P<0.01) and soil available N (P<0.01) were significant. Increased SOC coincide with the pe-riods of litter production and the harvest of agricultural crop. The levels of PO4-P, NO3-N and NH4-N increased during summer. However, the increase in the concentration of some nu-trients was also observed in winter months which may be attributed to either plant senescence or change in the soil biological processes. Higher availability of NH4-N in soil under E. offici-nalis indicated relatively lower rate of nitrogen mineralization than under the legume species H. binata and C. mopane soil. Approximately two to three fold higher concentration of NH4-N was observed during monsoon (cropping period) and which probably was due to utilisation of nitrate by the agricultural crops and/or due to nitrogen fixation by V. radiata and moisture controlled net-nitrifications.