The artist's Pixiv commentary references another version uploaded to TINAMI; which, instead has 「このロリコンどもめ」 on the paper. (Just in case {soiling + production + rice growing on the field} had your mind wandering somewhere else..)
Also, a lighter translation for this image could be "Growing Rice is Growing Soil/Earth" ('Earth' being more proverb like).
Chitanda Eru
千反田えるRice growing is soil production
「米作りは土作り」 Phrase used to stress that rice farming is about growing soil. [Chitanda wrote this at the Kanya festival's calligraphy booth (ep12)]
