noun
seed ball; clay dumpling
A mixture of clay, compost, and seeds used in natural farming (自然農法). Rolled into balls and scattered to sow seeds without tilling.
自然農法では、粘土団子を畑にまいて種をまきます。
In natural farming, you scatter seed balls over the field to sow seeds.
土団子 can refer to a simple mud ball (often made by children), while 粘土団子 specifically refers to the seed ball used in natural farming.
Compound of 粘土 (clay) and 団子 (dumpling, ball). The term was popularized by Masanobu Fukuoka's natural farming method.