Use an overlay over default_dirt.png for soil

mods/farming/nodes.lua

@@ -18,7 +18,7 @@ minetest.override_item("default:dirt_with_grass", {
 
 minetest.register_node("farming:soil", {
 	description = "Soil",
-	tiles = {"farming_soil.png", "default_dirt.png"},
+	tiles = {"default_dirt.png^farming_soil.png", "default_dirt.png"},
 	drop = "default:dirt",
 	is_ground_content = true,
 	groups = {crumbly=3, not_in_creative_inventory=1, soil=2, grassland = 1, field = 1},
@@ -32,7 +32,7 @@ minetest.register_node("farming:soil", {
 
 minetest.register_node("farming:soil_wet", {
 	description = "Wet Soil",
-	tiles = {"farming_soil_wet.png", "farming_soil_wet_side.png"},
+	tiles = {"default_dirt.png^farming_soil_wet.png", "default_dirt.png^farming_soil_wet_side.png"},
 	drop = "default:dirt",
 	is_ground_content = true,
 	groups = {crumbly=3, not_in_creative_inventory=1, soil=3, wet = 1, grassland = 1, field = 1},