diff --git a/data/mods/desert_region/mapgen/earth.json b/data/mods/desert_region/mapgen/earth.json
index ca61527acf60f..273b0c5814b93 100644
--- a/data/mods/desert_region/mapgen/earth.json
+++ b/data/mods/desert_region/mapgen/earth.json
@@ -308,13 +308,15 @@
   {
     "type": "mapgen",
     "method": "json",
-    "om_terrain": "canyon_edge_ground",
+    "//": "z0 omts, actual mapgen is done by nests in the z-2 versions",
+    "om_terrain": [ "canyon_edge_ground", "canyon_corner_ground", "canyon_2way_ground", "canyon_3way_ground" ],
     "object": { "fallback_predecessor_mapgen": "field" }
   },
   {
     "type": "mapgen",
     "method": "json",
-    "om_terrain": "canyon_edge",
+    "//": "z-1 omts, actual mapgen is done by nests in the z-2 versions",
+    "om_terrain": [ "canyon_edge", "canyon_corner", "canyon_2way", "canyon_3way" ],
     "object": { "predecessor_mapgen": "open_air" }
   },
   {
@@ -489,18 +491,6 @@
       "terrain": { "#": "t_null", " ": "t_open_air" }
     }
   },
-  {
-    "type": "mapgen",
-    "method": "json",
-    "om_terrain": "canyon_corner_ground",
-    "object": { "fallback_predecessor_mapgen": "field" }
-  },
-  {
-    "type": "mapgen",
-    "method": "json",
-    "om_terrain": "canyon_corner",
-    "object": { "predecessor_mapgen": "open_air" }
-  },
   {
     "type": "mapgen",
     "method": "json",
@@ -673,18 +663,6 @@
       "terrain": { "#": "t_null", " ": "t_open_air" }
     }
   },
-  {
-    "type": "mapgen",
-    "method": "json",
-    "om_terrain": "canyon_2way_ground",
-    "object": { "fallback_predecessor_mapgen": "field" }
-  },
-  {
-    "type": "mapgen",
-    "method": "json",
-    "om_terrain": "canyon_2way",
-    "object": { "predecessor_mapgen": "open_air" }
-  },
   {
     "type": "mapgen",
     "method": "json",
@@ -857,18 +835,6 @@
       "terrain": { "#": "t_null", " ": "t_open_air" }
     }
   },
-  {
-    "type": "mapgen",
-    "method": "json",
-    "om_terrain": "canyon_3way_ground",
-    "object": { "fallback_predecessor_mapgen": "field" }
-  },
-  {
-    "type": "mapgen",
-    "method": "json",
-    "om_terrain": "canyon_3way",
-    "object": { "predecessor_mapgen": "open_air" }
-  },
   {
     "type": "mapgen",
     "method": "json",