In vanilla technology Landfill available for Science Pack 1 & Science Pack 2 x50.
Some mods changes the recipe and technology of obtaining landfill. I do not remember which mod make discover of technology Landfill Science Pack 1 & Science Pack 2 > x375. I offer compost to make fuel for basic-farmland. To get a straw you can use it for growth.
Code pieces:
changes.lua
change line 72:
data.raw.item["landfill"].fuel_category = "humus"
prototypes/category.lua
change line 83:
name = "humus",
prototypes/entity.lua
change line 57:
fuel_categories = {"humus"},
prototypes/item.lua
add 2 lines after 47:
fuel_category = "humus",
fuel_value = "2500J", -- because 1 "landfill" 500kJ = 200 "compost".
full changes link: https://github.com/Oceanel51/Food-Industry/commit/c9ece9dca7a10031d752d5f419ca44de0efbc660?diff=split