In addition, an extra experiment was done to visualization of the P diffusion zone and comparison with KH2PO4 and Struvite. Then, Fig. and S4, show the P radial diffusion for the sample 2h/600 rpm in soil compared to the precursor (KH2PO4) and struvite (a low P diffusion material with ideal formula NH4MgPO4•6H2O) after 2 and 30 days of fertilizers application. At day 2 it is possible to see that struvite was not able to release any phosphorus, while sample 2h/600rpm the P diffusion reach a value of 1.99 cm a significant value compared to 2.62 cm for KH2PO4, a source of P considered extremely soluble. After 30 days, struvite starts P delivery, but sample 2h/600 rpm has a control release keeping lower values compared to KH2PO4. In summary, results showed that the P radial diffusion profile from sample milled for 2h/600 rpm is intermediate, 34% faster than struvite and 22% slower than precursor at the end of 30 days. The kinetic study of K release in soil shows a slight decrease at 3 days when 2h/600rpm sample is compared to KH2PO4, after that, both materials reach around 100% release (Fig. ).