As we look to maximize crop yields in an increasingly hostile environment, newer technologies are providing ways to recover valuable crops.

Harvested crops are often washed away in river runoff or farm runoff. The purple sludge on the back axle of a tractor or the silage pile in a meat packer’s cattle feed tank are toxic wastes that come from the energy conversion needed to grow the product. But it’s like gold in reverse: these polluting toxins are becoming valuable environmental assets.

What to do: Consider crop rotation, which helps minimize erosion, saves farmers money and gives the world a break. Plant more organic materials, such as grasses, before tilling your land.

If you’re a farmer, you can also make your own biochar by gradually burning liquid manure and non-organic plant matter (such as compost and shredded paper) from your farm and adding water and nutrients to the material. This is not necessarily the best way to make this concrete soil conditioner, but if you can use a large, flat surface, then it may be a beneficial way to make good soil look like grass. Research shows that we need to replace fossil fuel emissions from agriculture with renewable energy. Biochar is also opposed to organic regulatory groups because it is widely distributed and compostable, but it is a bit too smelly to be considered a true green crop.