© Provided by Xinhua URUMQI, April 12 (Xinhua) Towed by a driverless tractor, a hill-drop planter moves forward and spreads out corn seeds at a fixe
URUMQI, April 11 (Xinhua) Towed by a driverless tractor, a hill-drop planter moves forward and spreads out corn seeds at a fixed spacing. Meanwhile, a seed r