Scientists Estimate That Pesticides are Reducing Crop Yields by ONE-THIRD

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Scientists Estimate That Pesticides are Reducing Crop Yields by ONE-THIRD

 

 

 

Over the last forty years nitrogen fertilizer use has increased seven-fold and

nearly every acre of intensively farmed, conventional cropland is treated with

pesticides. A team of scientists explored the impact of pesticides and other

environmental toxicants on symbiotic nitrogen fixation (SNF) brought about by

Rhizobium bacteria (Fox et al., 2007). Their findings were published June 12,

2007 in the prestigious Proceedings of the National Academy of Sciences (read

full study here).

 

The team describes the critical role played by SNF in supporting crop yields and

environmental quality. SNF has great potential to reduce farm production costs -

a factor of growing importance as rising natural gas prices push upward the cost

of nitrogen fertilizers. In Brazil, SNF from soybeans reduces production costs

an estimated $1.3 billion per year. The research by Fox et al. (2007) explored

in depth the signaling processes between plants and bacteria colonizing plant

roots - processes that govern the degree of SNF and the production of certain

phytochemicals. They focused on the ways that pesticides can disrupt signaling

and impair the efficiency of SNF. Some 30 pesticides are known to disrupt SNF;

the most widely used pesticide in the United States, glyphosate (Roundup) is

known to be toxic to nitrogen fixing bacteria.

 

The " Conclusions�? section of the paper begins by stating:

 

" The results of this study demonstrate that one of the environmental impacts of

pesticides and contaminants in the soil environment is disruption of chemical

signaling between the host plants and N-fixing Rhiz(obia) necessary for

efficient SNF and optimal plant yield.�?

 

Drawing on their recent work and other published studies, the team projected

that pesticides and other contaminants are reducing plant yield by one-third as

a result of impaired SNF. This remarkable conclusion suggests one mechanism, or

explanation of the yield-enhancing benefits of well-managed, long-term organic

farming systems.

 

Source: " Pesticides reduce symbiotic efficiency of nitrogen-fixing rhizobia and

host plants�?

 

Authors: Jennifer E. Fox, Jay Gulledge, Erika Engelhaupt, Matthew E. Burrow, and

John A. McLachlan.

 

Proceedings of the National Academy of Sciences, Vol. 104, No. 24, June 12,

2007.