Old Things Are New Again

Modern Farmer highlights seven recommendations from a late-19th century farm guide that are still useful. One that's back to being cutting edge:

4. Field peas make a great green manure

I have tried peas as a fallow crop for the past three years, and find them the best and cheapest substitute for barn-yard manures that the poor land farmer can find. If all the farmers would use every means in their power to feed and improve their lands, we would soon have a different country from the present.

Legumes like the field pea (AKA black peas, Austrian winter peas, spring peas or Canadian field peas) still are great cover crops that can help farmers reduce erosion, retain moisture in their fields and improve their yields. Field peas “certainly provide a lot of nitrogen,” says Andy Clark, communications director for Sustainable Agriculture Research & Education, and the editor of Managing Cover Crops Profitably.
Today, Clark notes, few farmers have the luxury of fallowing a crop for an entire growing season (with some exception out West, where a summer crop of field peas can maintain soil moisture through a dry summer, prior to wheat planting in the fall.) As a winter cover crop, however, field peas can still be a good bet.

We tried Austrian winter peas as a cover crop two years in a row.  I'm not sure how much nitrogen boost we got from them, but it was pretty amazing how much they grew in the spring prior to spraying them.  Cover crops are definitely an old practice that's come back in a big way.