For farmers, knowing exactly when to water a crop, how much it needs, and whether changing conditions put a harvest at risk can make all the difference. But as climate change brings more unpredictable rainfall, extreme heat, and other shocks to the world’s food systems, making those decisions can increasingly become a guessing game. Luckily, some are hard at work removing that guesswork altogether. Based in Nigeria, Stephanie Meltus is the fou…