YOU SAID:
the dragon needed to make manure
INTO JAPANESE
ドラゴンは肥料を作る必要があった
BACK INTO ENGLISH
The dragon needed to make fertilizer.
INTO JAPANESE
ドラゴンは肥料を作る必要がありました。
BACK INTO ENGLISH
The dragon needed to make fertilizer.
That didn't even make that much sense in English.