A potato belt bed planter was modified by adding a precision mechanical device for nano fertilizers. It was consisted of a steel land wheel transmitted the motion to a metering unit via a transmission system designed to operate without effect on its performance. The planter was tested at five metering gate width of 5,10,15,20, and 25 mm, five metering rotary distributer reduction ratio at four planting forward speeds 0.97, 1.11, 1.25 and 1.39m/s. The results indicated that the required application rate (0.028 Mg/feddan) was achieved at reduction ratio between the land wheel and fertilizer rotary distributer (1:1.56), it was 0.0299,0.0297,0.0288, and 0.0291 Mg/feddan at forward speeds 0.97,1.11,1.25, and 1.39 m/s respectively. The field capacity before and after the modification was 1.5, 1.67, 1.82, and 2.01 feddan/h at forward speeds 0.97, 1.11, 1.25, 1.39 m/s respectively. The specific energy was 7.20, 8.29, 7.15, and 7.30 kW.h /feddan at forward speeds 0.97, 1.11, 1.25, 1.39 m/s respectively. The planter total operating costs without modification was 568.5 EGP/h and 605.5 EGP/h with modification. The cost of planting one feddan without modification was 312.3 EGP and 332. 7 EGP with modification. The planter indicated (NPV) of 41666.4EGP at 14 % interest rate. Also, the planter (PBP) was 3.1 year. The potato average yield in the experimental area with Spunta  variety was 15.1 Mg/feddan with common fertilization and 16.2 Mg/feddan with nano fertilization. This means the modification success to add the required amount of fertilizer and added 2199.6 EGP to each feddan profit.