Usual practice was to stand the pikes in the ground, vertically, point-up. This keeps the pike off damp ground, so it stays drier. One important function of buttspikes on pikes was to make it easier to store the pikes in this way when camping. It's an old practice, going back to ancient times - Greek hoplites would stand their spears upright in the same way.

Some contemporary art showing this:

• Late 16th century; note the pikes standing upright behind the cannons at the left-hand side of the camp: https://commons.wikimedia.org/wiki/File:Kulturbilder_481-482.JPG

• From 1675: https://www.rijksmuseum.nl/nl/collectie/RP-T-00-143

Also, a different way to stand pikes upright, from 1542. Here, pikes are stuck upright in straw-covered structures:

http://www.zeno.org/Kunstwerke/B/Cranach+d.+J.,+Lucas%3A+Die+Belagerung+von+Wolfenbüttel,+Gesamtansicht

Note that these structures are hollow - they aren't just piles of hay, but must be a framework covered in straw.