Where have all the lupins gone?

Last autumn I bought €50 of lupin seeds and sowed them by hand and rotavated them in. They germinated well and grew. But in this huge expanse not one remains after snow, frosts and biting winds.

They were to be a green manure crop fixing nitrogen into the soil. But they are gone but for one sheltered terrace.

But the soil has broken down to a light pillowy loam.

It is very dry and I planted broadbeans and garlic elsewhere.