August 29, 2013 – Since growing green manure makes such great sense, I finally decided to incorporate it into my permaculture approach to growing veggies. Unfortunately, I didn’t know that hairy vetch – my green manure of choice – doesn’t fix nitrogen in the soil until spring. I’ll be piling leaves and pine straw on top of the hairy vetch in November, so this time around I’ll only gain the organic vegetative matter, moisture retaining capacity, and soil aerating qualities of the vetch. Still, I look forward to the day when I can allow the vetch to grow to full maturity. The reason for that is that cover crops, i.e. green manure, fix enough nitrogen to fertilize one year’s entire crop of even a heavy feeder like corn. In fact, last year the average cover-cropping corn farmer in Illinois, Iowa, Nebraska and Kansas enjoyed an average yield of 122 bushels per acre, despite the drought. Those not employing a cover crop grew only ...
Understanding the global-warming world: causes and ramifications.