manganese deficiency

The Magnitude of Manganese Deficiency Caused by Glyphosate

Justin PlattBlog, Foliar Nutrition

Glyphosate is the active ingredient in Roundup®. This product enjoys widespread usage on core food crops. Genetically engineered corn, soy, canola, cotton, alfalfa and other crops are 

“Roundup®-Ready”, which means that they aren’t killed by the herbicide. It doesn’t, however, mean that they are completely safe, nor completely healthy. 

Let’s first talk about the effect of glyphosate on plants

Experiments have shown that applying glyphosate on herbicide-tolerant maize and soybeans reduces the efficiency of manganese (Mn) uptake and physiological efficiency by 10 to 50%. The variation depends on the genetic nutrient uptake efficiency of the particular transformed variety or hybrid.

Glyphosate-induced Mn deficiency can compromise plant resistance, allowing diseases to proliferate after glyphosate is applied for weed control. The greatest impact can be expected on soils with low micronutrient availability. 

Other physiological effects of glyphosate include:

  • Reduced uptake and translocation of Iron (Fe), Potassium (K), and Manganese (Mn)
  • Physiological immobilisation of Mn
  • Drought stress
  • Early maturity

It’s been proven that glyphosate weed management programs have the potential to influence all components of the “plant disease triangle”:

  • Reducing plant uptake and translocation efficiency
  • Changing soil biology
  • Modifying nutrient form or availability in the environment

In the soil, glyphosate can cause a shift in the soil microbial populations and cause nutrient deficiencies of Boron (B), Fe, Mn, and Zinc (Zn). Some authors have proposed that the cause of these nutrient deficiencies is the alteration of the soil microbial communities by glyphosate. This leads to the transformation of these nutrients into forms of lower availability to plants. 

When it comes to human health, glyphosate was previously thought to be harmless. However, it was classified as ‘probably carcinogenic to humans’ by cancer experts at the World Health Organisation in 2015. 

Many diseases and conditions are on the rise along with glyphosate usage in agriculture, particularly on corn and soy. These include:

  • Anxiety disorder
  • Autism
  • Osteoporosis
  • Renal lithiasis
  • Inflammatory bowel disease
  • Osteomalacia
  • Cholestasis
  • Infertility
  • Thyroid dysfunction
  • Alzheimer’s disease 
  • Parkinson’s disease 

Not coincidentally, these conditions can be substantially explained by the dysregulation of manganese utilisation in the body, possibly due to glyphosate.

Manganese is an important nutrient that is required in small amounts for multiple essential functions in the body:

  • Mn superoxide dismutase protects mitochondria from oxidative damage
  • Chondroitin sulfate synthesis depends on Mn (deficiency leads to osteoporosis and osteomalacia)
  • Lactobacillus (often deficient in autism patients) depend critically on Mn for antioxidant protection
  • Lactobacillus probiotics also can treat anxiety
  • Reduced gut Lactobacillus leads to overgrowth of the pathogen, Salmonella
  • Sperm motility depends on Mn

We know that glyphosate reduces the availability of manganese and other minerals in both plants and animals, so it follows that glyphosate in our food, atmosphere and bodies can have negative impacts on our health.

So, how to move on to greener pastures? 

If you have decided to transition to regenerative farming techniques, eliminating (or reducing) glyphosate applications will certainly form part of your journey.

Along with adopting practices such as crop rotation, no-till and cover cropping, you may need to look at remediation treatments for micronutrient deficiency (particularly Fe, Mn, Zn). 

High in seven important trace elements, Zylem’s Micros Z addresses common trace element deficiencies in many South African soils, including deficiencies in Zinc and Manganese which have been rendered unavailable where glyphosate is frequently used.

Invest in your soil and plant’s Zinc and Manganese levels. Find out more about Micros Z and our soil health solutions: 

Alex bio pic

About the Author: Alex Platt

Alex is Business Development Manager at Zylem. He’s inspired by the potential of regenerative farming and takes a special interest in the technology and products that are moving agriculture in a more sustainable direction.