Why We Don't Use Glyphosate (AKA Roundup)

September 20, 2020

This week, a friend strongly recommended that I use glyphosate, AKA Roundup, to keep our fence lines clear of brush.  This is not the first time that friends have tried to convince me of the benefits of glyphosate use....  (Green brush conducts the electricity on the fence straight into the ground with the end result that our fence is not as hot as it should be when there's lots of growth under and around the hot wires.)

This friend was well meaning.  He was concerned at the amount of time and the wearing effect of this labor (I've let many of the fence lines get away from me this summer and it is now a massive undertaking involving removal of blackberry, multi-flora rose, thorny vines, saplings, tall grass and worse... ).

When I explained to him that application of glyphosate has lasting and deleterious effects on the soil, he argued that that wasn't true.  He challenged me to prove it to him...

At first I was angry!  I don't need to prove anything to this friend (in my spare time - which I have little of).  He's not really a customer and likely never will be. 

I thought about it, cooled off, reconsidered and came to the conclusion that I had an opportunity to educate this friend.  After all, he did ask me to prove it to him. 

I also have the opportunity to share my findings with you and to add the information to our website as a blog post.

Fast forward -  after more than three hours of research, I have discovered that available research is OVERWHELMING.  There are so many research papers out there documenting the negative effects of glyphosate use....  all published in respectable scientific journals.

I could, literally, spend weeks on the subject and have no hope of covering it all...

So, below is a quick summary of glyphosate effects on soil and soil life.  The image is linked to it's source - so if you'd like to read the entire article, please click on the image!  The article does not, unfortunately, include sources and I could not find the sources listed on the website either.  Still, I believe that the list is an accurate summary of the concerns associated with the use of glyphosate.


To support the above summary, I selected five short research paper summaries, with citations.

No way I can include all that I found, but this handful should be enough to make my point that there is legitimate concern over the use of glyphosate!  A couple of them cover soil and soil organisms, one addresses testing in rats and another looks at the impact herbicide and fungicide use by applicators (often farmers) in their children!!  As a farmer, I found the that last one to be very interesting.

I even included one source which makes the case that glyphosate does not impact soil.

 - "The relative abundance of Acidobacteria decreased in response to glyphosate exposure while proteobacteria increased.  The decrease in acidobacteria is concerning because they are involved in biogeochemical processes, and significant changes in nutrient status of the rhizospere could result." 

What does this mean in laymen's terms?  It means that nutrient availability to plants, and other micro organisms, could be reduced."

Rhizosphere definition:  the region of soil in the vicinity of plant
roots in which the chemistry and microbiology is influenced by their growth, respiration, and nutrient exchange.

Source: "Glyphosate effects on soil rhizosphere-associated bacterial communities" from Science of the Total Environment Volume 543, Part A 1 February 2016, Pages 155-160:

- Glyphosate:

"(1) stimulates microbial respiration particularly on
soils with a history of glyphosate application;

(2) has no significant
effect on functional diversity (EL-FAME) or microbial biomass
K; and

(3) does not reduce the exchangeable K (putatively available to plants) or affect non-exchangeable K. The respiration response in soils with a long-term glyphosate response would suggest there was a shift in the microbial community that could readily degrade glyphosate but this shift was not detected by EL-FAME."

Source:  According to "The effect of glyphosate on soil microbial activity,
microbial community structure, and soil potassium," from Pedobiologia,
Volume 55, Issue 6, 10 November 2012, Pages 335-342:

- "Tests on lab rats suggest that maternal exposure to glyphosate disturbed
the masculinization process in male offspring and promoted behavioral
changes and histological and endocrine problems in reproductive

Source: "Glyphosate impairs male offspring reproductive development by disruption gonadotropin expression" by Romano MA, Romano RM, Santos LD, et al. Glyphosate impairs male
offspring reproductive development by disrupting gonadotropin
expression. Arch Toxicol. 2012;86(4):663-673. doi:10.1007/s00204-011-0788-9:

- "Herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services."

Source:  Zaller, J., Heigl, F., Ruess, L. et al. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem. Sci Rep 4, 5634 (2014).

- "We previously demonstrated that the frequency of birth defects among children of residents of the Red River Valley (RRV), Minnesota, USA, was significantly higher than in other major agricultural regions of the  state during the years 1989-1991, with children born to male pesticide applicators having the highest risk. The present, smaller cross-sectional study of 695 families and 1,532 children, conducted during 1997-1998, provides a more detailed examination of reproductive health outcomes in farm families ascertained from parent-reported birth defects. In the present study, in the first year of life, the birth defect rate was 31.3 births per 1,000, with 83% of the total reported birth defects confirmed by medical records. Inclusion of children identified with birth or developmental disorders within the first 3 years of life and later led to a rate of 47.0 per 1,000 (72 children from 1,532 live births). Conceptions in spring resulted in significantlymore children with birth defects than found in any other season (7.6 vs. 3.7%). Twelve families had more than one child with a birth defect (n = 28 children). Forty-two percent of the children from families with recurrent birth defects were conceived in spring, a significantly higherrate than that for any other season. Three families in the kinships defined contributed a first-degree relative other than a sibling with the same or similar birth defect, consistent with a Mendelian inheritance pattern. The remaining nine families did not follow a Mendelian inheritance pattern. The sex ratio of children with birth defects born to applicator families shows a male predominance (1.75 to 1) across specific pesticide class use and exposure categories exclusive of fungicides. In the fungicide exposure category, normal female births significantly exceed male births (1.25 to 1). Similarly, the proportion of male to female children with birth defects is significantly lower (0.57 to 1; p = 0.02). Adverse neurologic and neurobehavioral developmental effects clustered among the children born to applicators of the fumigant phosphine (odds ratio [OR] = 2.48; confidence interval [CI], 1.2-5.1). Use of the herbicide glyphosate yielded an OR of 3.6 (CI, 1.3-9.6) in the neurobehavioral category. Finally, these studies point out that (a) herbicides applied in the spring may be a factor in the birth defects observed and (b) fungicides can be a significant factor in the determination of sex of the children of the families of the RRV. Thus, two distinct classes of pesticides seem to have adverse effects on different reproductive outcomes. Biologically based confirmatory studies are needed."

Source:  V Garry, M. Harkins, L. Erickson, L. Long-Simpson, S. Holland, and B. Burroughs.  Birth defects, season of conception, and sex of children born to pesticide applicators living in the Red River Valley
of Minnesota, USA.Environmental Health Perspective.  2002 June;  110 (suppl 3):  pages 441-449

Amie Herrera

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