HANGZHOU, May 8 (Xinhua) -- Outside the Renhe grain depot in Hangzhou, capital of east China's Zhejiang Province, the early-summer heat was sticky and oppressive. Inside, however, grain kernels were nestled in a crisp, 19-degree-Celsius "climate-controlled suite."

This is the front line of China's green grain storage revolution. At a national conference on integrated green storage technology held in the city in late April, the National Food and Strategic Reserves Administration (NFSRA) announced that 40 new demonstration sites will be built across the country this year, with 100 model granaries set to cover all seven major grain ecological zones by 2027.

China, the world's largest grain producer, harvested a record 714.88 million tonnes in 2025. This marks the second consecutive year that the country's annual output has topped the 700-million-tonne mark, according to the National Bureau of Statistics.

Despite the bumper harvests, the country maintains a tight long-term supply-demand balance. Boosting storage technology has thus become a strategic lever for ensuring food security.

To this end, the green grain storage integration and demonstration program was first launched in 2025, with an initial batch of 30 pilot sites rolling out nationwide.

This strategy is already paying off. According to the NFSRA, China now has over 730 million tonnes of standard warehouse capacity, of which 220 million tonnes are equipped for low-temperature and quasi-low-temperature storage, and more than 55 million tonnes use controlled-atmosphere technology. The comprehensive loss rate during a full storage cycle has been kept under 1 percent.

At the Renhe depot, a suite of technologies was on vivid display.

"The reading right now shows 19 degrees Celsius and 65 percent humidity inside, well within the technical standards for quasi-low-temperature grain storage," said Wan Xiaojin, director of the depot, pointing to a thermohygrometer on the warehouse wall.

A key enabler of that stable climate is the air-supported membrane silo, now being rolled out across multiple regions. Depot staff affectionately describe it as a giant "breathing white chubby" -- a playful nickname for the plump, dome-shaped structure.

Grain stored inside is like living in an air-conditioned room with constant temperature and humidity levels.

The secret lies in three layers of technology embedded in the roof, the grain pile and the walls: solar shielding, active cooling and energy efficiency, working together so the grain "sleeps in a good house," said Wang Hongli, chief technician to manage the membrane silos.

But a good house also needs regular health check-ups. Before entering the warehouse, every batch of grain passes through an intelligent inspection gate equipped with high-precision detectors -- essentially a CT scanner for kernels.

Five images are taken of each individual maize kernel from five different angles, ensuring that there are no blind spots in the quality inspection. For a standard 100-gram maize sample, the entire scan takes less than 100 seconds, said Wang Liangliang, a technician of the grain smart check team.

Then there is the dock, which held one of the biggest surprises.

A grain ship on the Grand Canal, the world's longest artificial waterway stretching from Beijing to Hangzhou, just berthed. A thick suction pipe reached into the hold, and wheat was drawn up like water through fully enclosed pipelines, traveling straight into the warehouse. From ship to silo, not a single grain was spilled, and the site remained virtually dust-free.

"The entire assembly line operates through sealed pipelines," said Ma Guojun, head of the storage and transport section at the depot. "Our operation won't be affected no matter how the weather changes."

Once the grain is inside, another former headache has been solved. Flattening the grain pile used to mean sending workers several meters down into the mass to shovel it level by hand. Now the job falls to a second-generation "leveling robot," which can operate autonomously for around eight hours on a single charge.

The technologies on show in Hangzhou represent more than local upgrades.

Instead, they are part of a nationally orchestrated push. The goal is to build a cohesive green storage system resting on five pillars: upgrading warehouse performance, enabling clean and efficient grain handling, deploying intelligent monitoring and early warning, applying green pest and mold control, and rigorously evaluating all measures against scientific benchmarks -- a system officials describe as tailored to local conditions, not one-size-fits-all.

Zhang Zhongjie, chief researcher at the NFSRA academy, noted that by pursuing green, intelligent and integrated development, China is building safe, green and smart granaries to ensure that "every single grain stays fresh."