This year a handful of farmers in the San Joaquin Valley have new crop. But it’s not something you’ll find at your weekend farmer’s market. Instead it’s carbon. A new program funded by the state’s cap-and-trade initative aims to help farmers add cover crops to their fields, with the idea that more carbon will be stored in the soil in the form of organic matter. It’s part of the state’s effort to fight climate change. We spoke with journalist Nathanael Johnson of Grist, who recently reported about the California Healthy Soils Program at a farm near Gustine.