The environmental benefits of organic farming have been widely acknowledged. In a long-term study of organic, conventional, and integrated apple orchards in Washington State, a team of scientists documented several important environmental benefits.
In the organic blocks of trees, nitrogen (N) losses to groundwater and the atmosphere were reduced relative to conventional agriculture. Annual nitrate leaching was 4.4–5.6 times higher in conventional plots than in organic plots, with the integrated plots in between. The organically farmed soils exhibited higher potential denitrification rates, greater denitrification efficiency, higher levels of organic matter, and greater microbial activity than the conventionally farmed soils.
The study demonstrates that organic and integrated fertilization practices support more active and efficient soil microbial communities, shift the balance of N2 emissions and nitrate losses, and reduce environmentally damaging nitrate losses. These benefits boost the overall efficiency of nitrogen utilization within an organic system, and point the way toward improved environmental and economic farming system performance.
Authors: Susan B. Kramer, John P. Reganold, Jerry D. Glover, Brendan J.M. Bohannan, and Harold A. Mooney
Proceedings of the National Academy of Sciences, March 21, 2006, Vol. 103, No. 2: pages 4522,4527.