Guizhou has transformed its notoriously juddering terrain from a bane into a boon. Turns out, tricky geology can advance technology, Erik Nilsson discovers.

Editor's Note: This is Part 3 of the six-part Yangtze diaries series based on journalist Erik Nilsson's recent 35-day, 2,000-kilometer journey to 11 cities to discover how the Yangtze River Economic Belt has transformed over the 40 years since the reform and opening-up. Scan the code to watch the video.

I recently used an app to water a mountainside kiwi field in Guizhou's Shuicheng. A few taps on a phone and the taps of the sprinkler systems started spurting.