Growing a green manure in winter prevents soil from having nutrients washed away by rain or snow, and some varieties have a fibrous root system that helps to give the soil structure. Clover is a ...

crimson clover and hairy vetch. Both crops can pull nitrogen from the air to help them grow. This is called nitrogen fixation. "Green manures are crops used to improve soil fertility," says Muller.

Bob Blackshaw and his colleagues show that mowing can be an effective alternative to tillage for sweet clover termination. Sweet clover is an excellent green manure option that many organic producers ...