Hong Kong (CNN) China is sending five million officials to its villages, rice paddies and farms this month.

Their mission? To count the country's pigs, chickens, goat, yaks, cattle and crops as part of China's third agricultural census.

It's a massive undertaking that only happens once every 10 years and it's expected to show huge shifts in how China produces its food.

China has around 20% percent of the world's population but only about 7% of the planet's arable land, so what it does with it is extremely important.

In recent years, China has become the world's leading importer of farm products and has been buying tracts of land overseas in places like Australia, Argentina and Africa, sparking fears of land grabs.

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