diff --git a/src/terraform_cmd.cpp b/src/terraform_cmd.cpp
--- a/src/terraform_cmd.cpp
+++ b/src/terraform_cmd.cpp
@@ -184,7 +184,7 @@ static CommandCost TerraformTileHeight(T
  * @param text unused
  * @return the cost of this operation or an error
  */
-CommandCost CmdTerraformLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdTerraformLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const std::string &text)
 {
 	_terraform_err_tile = INVALID_TILE;
 
@@ -341,7 +341,7 @@ CommandCost CmdTerraformLand(TileIndex t
  * @param text unused
  * @return the cost of this operation or an error
  */
-CommandCost CmdLevelLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdLevelLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const std::string &text)
 {
 	if (p1 >= MapSize()) return CMD_ERROR;