  We use PCAC in the small $Q^2$ region in order to calculate the Adler sum
rule and the production of hadrons in the low energy region where resonances
dominate. We find very good agreement with the sum rule and with the computed
cross sections. We find a value $C_5^A(0)$ close to the Goldberger-Treiman
prediction. The formalism is general and can be applied to other reactions
shedding light into the dynamical transition from resonances to deep inelastic
scattering.
