LONG AN, Vietnam: Sixty-year-old Vo Van Van has been working with one of Vietnam's largest rice exporters, the Loc Troi Group, for the past two years and is using a different method of irrigation known as alternate wetting and drying. This requires less water than traditional farming since his paddy fields aren't continuously submerged. Less methane is also produced.

Using the drone to fertilize the crops saves on labor costs. It also ensures precise amounts of fertilizers are applied. Too much fertilizer causes the soil to release Earth-warming nitrogen gases.