Biomass and concentration of nutrients and silicon in sugarcane grown on soil fertilized with diatomite

Silicon (Si) plays an important role in sugarcane, but there is a gap of information regarding the potential of diatomite as a Si fertilizer to this crop. Here, we assessed the effects of five rates (equivalents to 75; 150; 225; 300 and 375 kg ha-1 Si) of a diatomite-based fertilizer on the biomass yield and concentration of nutrients and Si in sugarcane plants grown on a sandy soil. The efficiency of the extractants acetic acid and calcium chloride in predicting Si uptake was also assessed. Results showed that diatomite was efficient in supplying available Si in the soil and increased Si concentration in the plant. The addition of diatomite significantly increased the available contents of P, K, Mn, Cu, and the cationic exchangeable capacity of the soil. The concentrations of N, P, Mn, Cu, and Zn in shoots were elevated, suggesting that the fertilizer can play a role in the efficient use of nutrients by sugarcane. The extractant 0.01 mol L-1 CaCl2 was better correlated with Si concentration in plants than 0.5 mol L-1 acetic acid. Therefore, CaCl2 is the recommended extractant to estimate Si availability because of its higher efficiency and lower cost.