“…In this perspective, plant ash can be applied as alternative fertilizer because it contains considerable amounts of the major nutrients required for plant growth, such as calcium, magnesium and potassium (Etiégni and Campbell, 1991;Saarsalmi et al, 2001;Bonfim-Silva et al, 2015;Iqbal and Lewandowski, 2016), low nitrogen (Saarsalmi et al, 2001) and phosphorus (Hakkila and Halaja, 1983;Santos et al, 2014). As soil corrective and alternative or even complementary fertilizer, plant ash is widely studied (Adriano et al, 1980;Vance, 1996;Demeyer et al, 2001;Füzesi et al, 2015;Bezerra et al, 2016;Pereira et al, 2016) and are still scarce in relation to tropical grasses. The use of this biomass for the production of thermal energy, producing wood ash, commonly used in industries, is growing worldwide due to the need to use renewable energy sources in response to concerns about climate change (McKendrey, 2002), higher oil prices and the need for energy security of the countries (EU, 2009, Titus et al, 2010.…”