Usage: TSP has several agronomic advantages that made it such a popular P source in many countries. It has the highest P content of dry fertilizer s that do not contain N. Over 80% of the total P in TSP is water soluble, so it becomes rapidly available for plant uptake. TSP has several agronomic advantages that made it such a popular P source in many countries. It has the highest P content of dry fertilizer s that do not contain N. Over 80% of the total P in TSP is water soluble, so it becomes rapidly available for plant uptake. TSP also contains 15% calcium (Ca), providing an additional plant nutrient. TSP provides the readily phosphorous which promotes flower and fruit production and enhance the vegetable yields for best results, sufficiently water in after application.