英語時差：黑金農(nóng)業(yè)

Hey, Don, did you know that soil deterioration is one of the main contributors to global warming?

Uh, no. Yael. What do you mean?

Well, soil holds a big portion of the earth carbon in the form of organic matter. But when we work soil intensively and use chemical fertilizers, all that organic stuff breaks down quickly and gives off carbon dioxide that collects in the atmosphere.

Plus, the soil is depleted, right? Meaning that it’s less useful for growing food.

Right. But scientists at Delaware State University have found that an ancient method of fertilizing soil may help. Fifteen hundred years ago, people from the central Amzon area in south America made sort of charcoal by heating tree bark and animal bones without air. They used it to fertilize soil and the researchers’ve found that this soil is still some of the richest and most fertile in the world. Scientists call the charcoal biochar.

Does this stuff actually make plants grow better?

Yes. At least in small-scale experiments. The researchers grew wheat in greenhouse pots, some with biochar and some without. The wheat fertilized with biochar grew more quickly than the wheat without.

Wow, so this stuff could help feed people and improve soil.

That’s the idea. There is something about heating organic material that makes it more stable than raw plant residue. Instead of breaking down quickly and releasing carbon dioxide, it keeps carbon and nutrient soil for a really long time, even thousands of years. So it could also have a positive effect on global warming.

Cool.

More research is needed, of course. But biochar could end up chaning the way we think about farming.