MACRONUTRIENTES PRIMÁRIOS E PRODUTIVIDADE DA MANDIOCA CULTIVADA COM PÓ DE ROCHA NEFELINASIENITO E MICRORGANISMOS BIOSSOLUBILIZADORES

Abstract

The use of nepheline-syenite rock powder (PR), associated with the inoculation of biosolubilizing microorganisms, has aroused agronomic interest, as it is an alternative to reduce dependence on imported fertilizers, and can improve plant nutrition and productivity. The objective of this study was to evaluate the primary macronutrient content in the leaves and the productivity of cassava cultivated with three potassium sources (100% PR, 50% PR + 50% KCl and 100% KCl), associated with the inoculation of Bacillus amyloliquefaciens (Amy), Bacillus aryabhattai (Ary), Cladosporium cladosporioides (Cla), Amy + Bar; Amy + Cla; Ary + Cla and Amy + Ary + Cla. Higher foliar contents of K (14.2 g.kg-1) and P (1.47 g.kg-1) were obtained with the use of 100% KCl. As for N, the use of 100% PR (40.36 g.kg-1) and 50% PR to 50% KCl (41.15 g.kg-1) provided higher levels. As for the microorganisms, B. aryabhattai and B. amyloliquefaciens and their coinoculation were promising when in the presence of a poorly soluble K source (100% PR) and C. cladosporioides, and their combinations with B. aryabhattai and B. amyloliquefaciens were more promising when using KCl (100% KCl). The use of rock powder as a potassium source provided an increase in cassava productivity.