Volume 12 Article informations Monitoring and distribution of nitrogen and phosphorus in agricultural soil in semi-arid climate (Siliana. Northern Tunisia) Manel Allani a,*, Hatem Ibrahim a,b, Wissem Dhahbi c, Abdessatar Hatira a Abstract Nitrogen (N) and phosphorus (P) are the two most important nutrients in the soil, they have a very necessary role in agricultural soils. These two nutrients are essential for increasing agricultural yield. However, their application needs to be carefully evaluated to avoid the risk of contamination and degradation of soil quality. This study was carried out to understand the dynamics and the distribution of N and P in agricultural soil in northern Tunisia. The systematic application of N and P fertilizers to agricultural soils has become an integral part of agriculture. The choice of these two elements was guided by a double concern: one economic, because the study of the distribution of nitrogen and phosphorus, in this study site, makes it possible to reason the chemical fertilization by consequently, saving expensive fertilizer units, and the other environmental, such as taking into account the fertilizers provided by the different soil compartments makes it possible to avoid losses by lixiviation which can impact the quality of water and soil..... Key words: Distribution, Monitoring, Nitrogen, Phosphorus, Soil, Siliana-Tunisia.