Zhang Aiguo (R) prepares to fly a drone in a field in Changsha, Central China's Hunan province, March 20, 2014. In 2009, Zhang, who used to be a farmer, leased about 2,000 mu (133 hectares) of cropland with his friend in Xiangtan county, Hunan province, and they bought a drone to spray pesticides on the field last year. Zhang found that this was a very efficient method, and he then designed and made several drones based on the one they had bought. He simplified the control system and installed engines brought online. [Photo/Xinhua]