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

The Organic Center, 7/10/2007

Straight to the Source

 

 

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 & #65533;? 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. & #65533;?

 

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 & #65533;?

 

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.