Agronomic potential of four rock powders, pure or mixed, as soil remineralizers

Detailed knowledge of chemical, petrographic and mineralogical compositions as well the effects applying rock powder on soil chemical properties plant production are required for classifying these materials remineralizers (SR), according to Brazilian legislation in force. This study aimed evaluate potential powders siltstone, tephrite olivine melilitite, pure or mixed, improving fertility a Cambisol Nitisol yield soybean barley crops grown succession inside greenhouse. For that purpose, products were characterized their granulometry, compositions. Based results, it was verified which met requirements registration SR established by Normative Instruction Number 5 (NI5) from MAPA. Elemental grain size analyses indicated all tested NI5 SR. The mineral composition identified through confirmed performed via X-ray diffractometry techniques. Olivine melilitite rock, mixed with had highest agronomic when compared other powders, thus acknowledged Although little response evaluated soils crops, also meets requirements. Siltstone fulfilled most criteria, except exceeding maximum content free silica (quartz); therefore, likely does not meet its admittance