Nepheline Syenite and Phonolite as Alternative Potassium Sources for Maize

Some silicate rocks are a rich source of potassium (K), with the possibility for use in agriculture. The present study aimed to evaluate agronomic efficiency index (AEI) nepheline syenite (NS) and phonolite (PN) comparison chloride (KCl) as K maize production. An experiment was conducted greenhouse Ilha Solteira, São Paulo, Brazil. A hybrid grown 8 L pots filled 6 kg soil low concentration contrasting physical attributes (medium sandy texture). completely randomized design 3 × factorial scheme used, consisting three sources (NS, PN, KCl) six rates (0, 50, 100, 150, 200, 400 mg kg?1) four replications. All plants were harvested 45 days after emergence biomass production, macronutrient (N, P, K, Ca, Mg, S) uptake, stem diameter, leaf chlorophyll index. After crop harvest, collected further chemical evaluation, which included organic matter (OM), pH, cation exchange capacity (CEC), H+Al, Al, sum bases (SB), base saturation (BS), S. In addition, AEI NS PN also verified relation KCl. application had similar effect on (MO, SB, CEC, BS) well concentrations S, both soils. increase provided linear growth shoot dry matter. Leaf compared increased accumulation plants. Maize treated KCl largest AEI, followed by NS. However, results indicated maize, especially highest rates. This research demonstrated alternative maize.