function Coal()
  if turtle.getFuelLevel() < 40 and turtle.getItemCount(1) <2 then
    print "Bitte Treibstoff in den 1. Slot geben"
  end
end

function Refuel()
  if turtle.getFuelLevel() < 100 then
    turtle.select(1)
    turtle.refuel(turtle.getItemCount()-1)
  end
end

x=0
y=0

function Mv()
	Coal()
	Refuel()
	while not turtle.forward() do
		turtle.attack()
	end
end

function Startup()
	while turtle.forward() do
		x=x+1
	end
	turtle.turnRight()
	while turtle.forward() do
		y=y+1
	end
	turtle.turnRight()
	for l=1, x, 1 do
		Mv()
	end
	turtle.turnRight()
	for m=1, y, 1 do
		Mv()
	end
	turtle.turnRight()
end

function CheckBelow()
	success, data = turtle.inspectDown()
	if data.metadata == 7 then
		turtle.digDown()
		if data.name == "minecraft:carrots" then
			turtle.select(3)
			turtle.placeDown()
		elseif data.name == "minecraft:potatoes" then
			turtle.select(2)
			turtle.placeDown()
		end
	end
end

function CheckField()
	for j=1, y, 1 do
		for k=1, x, 1 do
			CheckBelow()
			Mv()
		end
		CheckBelow()
		if j%2 == 1 and then
			turtle.turnRight()
			Mv()
			turtle.turnRight()
		elseif not(j==y) then
			turtle.turnLeft()
			Mv()
			turtle.turnLeft()
		end
	end
	if y%2 == 0 then
		TurnAround()
		for k=0, x, 1 do
			Mv()
		end
	end
	turtle.turnRight()
	for j=0, y+1, 1 do
		Mv()
	end
	turtle.turnRight()
end

function TurnAround()
	turtle.turnLeft()
	turtle.turnLeft()
end

function Chest()
	TurnAround()
	for n=5, 16, 1 do
		turtle.select(n)
		turtle.drop()
	end
	TurnAround()
end

Startup()
while true do
	CheckField()
	Chest()
	os.sleep(900)
end