A method to store vegetables for a long time is in use in Thimpu district of Bhutan. Farmers dig a pit in the ground, which they warm by burning twigs in it. The size of the pit depends on the quantity of the surplus green vegetables and raddish to be stored. The raddish is then smashed and alternate layers of the raddish and green vegetables are filled in the pit. All voids are filled up by pouring warm water, and the vegetables are compressed by stamping with the feet. When the pit is full, it is made air-tight by covering it with soil and hay. The vegetables are allowed to ferment for about three weeks and then taken out and dried. Vegetables treated in this way can be stored for over a year under ordinary conditions to supplement the requirements in lean seasons.

Formulation: Dig a pit in the ground, warm it by burning twigs in it.
Ingredients: Warm water, hay, soil, twigs for burning.

"Storage Methods for Fruits and Vegetables"
https://www.researchgate.net/publication/317014767_Storage_Methods_for_Fruits_and_Vegetables

https://www.missouribotanicalgarden.org/Portals/0/Gardening/Gardening%20Help/Factsheets/Storage%20of%20Fruits%20and%20Vegetables43.pdf

"Effect of date of sowing and crop geometry on growth and yield parameters of forage mustard (Var. Chinese Cabbage)"
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.982.2706&rep=rep1&type=pdf