Photo/Illutration Dirt from a former rice paddy is cleared for replacement soil that will raise its overall height in the larger process of rehabilitating this fallow plot in Hanyu, Saitama Prefecture. (Provided by Taisei Corp.)

Taisei Corp. has developed technology to process dirt from construction sites into soil fertile enough to transform abandoned farmland into highly productive fields. 

The major general contractor said it uses recycled fertilizer made from composted food waste as well as sewage sludge in the process.

This system is designed to simultaneously regenerate local farmland and recycle resources, with Taisei aiming to commercialize the system in the near future. 

The company successfully conducted a demonstration test in 2024 where idle rice paddies in Hanyu, Saitama Prefecture, were restored and turned into plots to cultivate "edamame" green soybeans and other vegetables.

Using soil from construction sites in the prefecture, the company raised the height of a low-lying paddy (about 300 square meters) by about a meter when converting it into a field. 

In doing so, the company utilized its soil-improvement technology with help from microorganisms and by applying its landscaping expertise.

Recycled fertilizer made from composted food waste was then added to the field after the land was redeveloped.

Normally, it takes several years before previously fallow plots can achieve a stable harvest.

The demonstration test, however, defied this when the farmland yielded a standard-size harvest from the first year of development.

The company said that this technology makes it possible to cultivate large amounts of land that meets quality requirements. 

It plans to pitch the technology to municipalities troubled by abandoned farming plots and agricultural corporations seeking to consolidate farmland on a large scale with the aim of accepting orders in the next few years.

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