A simple rolling system was investigated and setting in the bottom of fertilizing unit to utilize the recommended amount of fertilizer adding to the seeds during/after planting. So that it can be used individually, to perform the fertilizing operation after planting, or combined with the drilling machine. The judging on the performances of fertilizer feeding unit with rolling system is identified under four different forward speeds (FS) of 2.5; 3.7; 5.0 and 8.5 km/h and different operating ratio between fertilizer unit landing wheel and rotating shaft of fertilizer rolling system (OR) under gate area (GA) of 15cm2. The granulated fertilizer (Potassium nitrate and Urea) were used in the experiment to assess the performance of the investigated rolling system on fertilizer application rate (kg/fedd.).The results of the study were compared statistically to obtain the most suitable treatments to the addition of activating doses of fertilizers during planting and growing crop service. The experimental results indicated thatthe recommended amount 12.0 kg/feddpotassium nitrate for the investigated rolling unit may be defined under forward speed of 5.0 k m/h and a Operating ratio of “1.0 to 2.0". On the other hand, at recommended amount 30.0 kg/fedd or 33.0 kg/fedd potassium nitrate for the investigated fertilizer system may be conformed under forward speed of 3.7 km/h and with a operating ratio of “1.0 to 4.1" or “1.0 to 4.8" respectively.