Yale Environment 360: Rice is a thirsty crop. Yet for the past three years, Alberto Mejia has been trying to reduce the amount of water he uses for irrigation on his 1,100-acre farm near Ibague in the tropical, central range of the Colombian Andes.
He now plants new kinds of rice that require less water. He floods his paddies with greater precision and has installed gauges that measure the moisture content of the soil. On a daily basis he can determine how much nitrogen the plants need, and he relies on more advanced...