Soil water sampler can extract water directly from soil through porous cup in the ground.
Water extracted can be used for chemical tests (pH, EC etc.) to check the state of soil nutrients.
There are two types; DIK-8392 is for field and DIK-8393 is for pot.

 

DIK-8392 Soil Water Sampler for field: https://www.daiki.co.jp/en/products/dik-8392e/

DIK-8393 Soil Water Sampler for pot: https://www.daiki.co.jp/en/products/dik-8393e/

YouTube: https://youtu.be/tFUhpNTEiAg