Farmers in Pakistan are replacing diesel-fueled pumps with solar energy to power the typical irrigation technique in a large part of the world’s fifth most populous country. Many farmers rely on the so-called tube wells—a water well and a motorized pump to take water from groundwater. Amid soaring diesel prices and unreliable electricity supply in recent years, more farmers are installing solar panels to help them with crop irrigation. The solar-powered tube wells provide smoother irrigation. Solar panels have steep upfront costs for…