The quality of soils to grow the very feedstocks to make biodiesel could be helped by a by-product of that green fuel’s production. This article from Farmers Weekly says Rothamsted Research in the United Kingdom found that applying biodiesel co-product (BCP) increased soil micro-organism numbers and this effectively “locked up” the nitrates in the soil until spring.
Researchers looked at three treatments to try and cut leaching, which included incorporating straw, growing meadowgrass and applying BCP in simulated field conditions.
“We found that BCP was the most effective soil amendment, rapidly increasing the abundance of soil micro-organisms and preventing more than 99% of nitrate leaching,” says Rothamsted researcher Marc Redmile-Gordon.
He adds that cutting nitrate losses from farmland would help protect the environment, especially watercourses, and could lead to lower nitrogen fertiliser rates.
The “very encouraging” results came in field trials conducted in the 2012-13 season when heavy nitrate leaching would have been expected after a wet harvest followed by an equally wet autumn.
The BCP treatment helps stimulate soil microbe numbers by giving them an energy source and then they suck up nitrate nutrients from the soil to feed this growth, says Dr Redmile-Gordon.
The nitrates are unlocked in the spring as soil microbe levels are reduced by warmer drier weather. The process mimics the use of cover crops over winter in mopping up nitrates in the autumn and then slowly releasing them in the spring.
The researchers believe this method could cut nitrogen fertilizer usage by about 10 percent. They do point out that it might require changing application methods.