The cubic sieve is an algorithm for computing discrete logarithm.
The initial step is to find a solution to
$x^3\equiv y^2z\pmod p$ such that $x^3\ne y^2z$ with $x,y,z$ of order $p^\alpha$.
But what does it mean to have $\frac{1}{3}\le\alpha\le\frac{1}{2}$? $\frac{1}{3}$ of what? Also, does it change anything for the variant of the algorithm working with finite fields having dimension >2 ?