Organomineral phosphate fertilizers: Agronomic efficiency and residual effect on initial corn development

Th is research investigated the efficiency and residual effects of two solid organomineral fertilizers on corn (Zea mays L.) shoot dry matter (SDM), P uptake, P recovery index, P use efficiency index, accumulated SDM (ASDM), and total P uptake. Th is was a greenhouse pot study where organomineral-granulated (OG) fertilizer, organomineral-pelletized (OM) fertilizer, and inorganic fertilizer mix (MM) were tested on a Eutropherric Red Latossol clay soil (Oxisol). Phosphorus (P) rates were 0, 25, 50, 100, and 200 mg kg⁻¹. Two plants were grown in each pot for 35 d before harvest; this cropping cycle was repeated consecutively four times on the same pots. Corn SDM for OM in the first cropping cycle was three times lower than for OG and MM at the highest P rate, was similar among all sources in the second and third cycles, and in the last cropping cycle was on average two times higher for the OM and MM compared with OG. Tissue P uptake was on average 50% greater for OM and MM than for OG. Corn ASDM and total P uptake were significantly greater (on average 35% for ASDM and 40% for total P uptake) with MM and OM than with OG for the majority of the rates. Th e P recovery index was the same in the first cropping cycle among all sources; however, it was significantly higher (60% on average) for MM and OM in the last two cycles than for OG. No difference in P use efficiency of corn plants was observed between fertilizer sources.