: The research goal was to develop a simplified method for estimating the available phosphorus for routine analysis. This study compared the measured Soil-P using the ICP-NaHCO 3 with the simplified extraction method (SM-P). The correlation (r=0.99) and the regression(using XLSTAT-Pro) were employed for comparing the data of available phosphorus content in soil samples for a variety of Moroccan soil types, with contrasted physicochemical characteristics: Ali Moumen, Oued Qibane, Ouled Said, Dower Hbata, Dower Lhfaya, and Had Ghoualem (are located using ArcGIS 10.1 and fertiMap). SM-P is most suited for soils with pH >= 7 and CaCO3 content above 5%. In this experiment, several parameters are modified, particle size, the type and degree of mechanical agitation ,the color development, and the adaptation of the reading at 860 nm, are improving the accuracy of P analysis, the high correlation of this method with ICP-NaHCO3 content can be an indication for it. The results of this experiment showed that SM-P can be the best method for predicting the available phosphorus, simple, quick, and easy to execute.

Results obtained showed that some essential manufacturing factors needs to be respected throughout the production loop. These factors will help obtaining a slurry exits with the desired chemical characteristics of P 2 O 5SE (33%), Al (10%), P 2 O 5SE + Citrate (34.5%), H 2 O (22%), P 2 O 5total (39%)). It is necessary to keep a temperature within 100 ± 5 ° C., with a vapor pressure of 6 to 7 bars, an average density of H 3 PO 4 (1470 g/l) and the solid rate in the feed acid less than 2%. After the reaction phase, the slurry is conveyed to the granulator where it is mixed with the recycled product at a recycling rate (RT) close to 3 and a K ratio between 0.1 and 0.2. This parameter is very important to be monitored to ensure a Good penetration of heat into the next phase in a relatively short time. During the drying process, the product humidity at the outlet must be in the range of 3.5% to 5% to allow the reaction to continue during the developing period. At the exit of the drying tube, the product is in very variable grains diameter (D), the objective of the following step is to extract the grain size range between 2 and 4 mm. To do so we changed the mesh size of the lower webs to 3/50 and 3.2 / 30 mm, which reduces the quantity of particle size less than 2%. Thus, the particles of diameter more than 3.15 mm must be continuously controlled to reach 64%. This portion will ensure conformity of the product for D 50 and for the two intervals [2-3.15 mm] and [3.15-4 mm]. In the Storage Hall the reaction continues, the unconverted phosphate will be attacked by the unreacted H 3 PO 4 , and according to a monitoring of the evolution of the chemical composition of the final product (TSP). The required ripening time is limited to 21 days. During this study, we were able to identify and modify a number of parameters in different production phases to improve the quality of TSP according to AFCOME, knowing that each phase of the process is a client of the previous phase and supplier of the next one.