  A microscopic approach has been employed to study the kaon and $\Lambda$
productions in heavy ion collisions. The productions of $K^+$ and $\Lambda$
have been studied within the framework of Boltzmann transport equation for
various beam energies. We find a non-monotonic horn like structure for
$K^+/\pi^+$ and $\Lambda/\pi$ when plotted against centre of mass energies
($\sqrt s_{\mathrm NN}$) with the assumption of initial partonic phase for
$\sqrt s_{\mathrm NN}$ beyond a certain threshold. However, the ratio
$K^+/\pi^+$ shows a monotonic nature when a hadronic initial state is
considered for all $\sqrt s_{\mathrm NN}$. Experimental values of $K^-/\pi^-$
for different $\sqrt{s_{\mathrm NN}}$ are also reproduced within the ambit of
the same formalism.
