Euler cycles and Mennicke symbols

Let $R$ be a smooth affine domain of dimension $d\ge 2$ over an infinite perfect field $k$. We establish a morphism from the Euler class group $E^d(R)$ to $U{m}_{d+1}(R)\mathrm{/}{E}_{d+1}(R)$, the group of elementary orbits of unimodular rows.