Glyphosate was invented and patented in the mid seventies by the Monsanto Corporation and marketed as “Roundup”. It became their flagship product until the patent expired in 2000. The lower priced generic glyphosate products should theoretically have decimated sales for Monsanto but they cleverly introduced their genetically modified “Roundup Ready” crops to maintain their market share. This technology involves the purchase of the treated seed and the required amount of Roundup. Roundup sales have actually increased in line with the widespread adoption of Roundup Ready crops in the US and elsewhere. 45,000 tonnes of glyphosate was applied to US farms and gardens last year but recent research suggests that the World’s favourite herbicide may not be as “soft” as was previously claimed and there may be several undesirable side effects.

Collateral Damage

Soil life is one of the unintended casualties of this weed killer. Algae are a plant-like creature that can be killed by plant killers. Algae produce carbohydrates through photosynthesis that are an important food source for beneficial fungi and bacteria in the soil. There is literally less food for the good guys when this sugar production is compromised. Glyphosate was originally marketed as a safe, sustainable, biodegradable option that would exit the soil shortly after killing the weed. It inhibits the production of essential amino acids within the plant and your weed dies within days. More recent research has revealed that both soil type and soil life impact the longevity of the chemical in the soil and it has been found to still be present up to 6 months after application in some soils. Even when it breaks down it can leave a metabolite that can remain present for years. During my years of consulting in Europe I have often encountered growers involved in intensive horticulture who claim that production declines over time with the use of glyphosate. They have monitored different blocks, based upon relative use of the herbicide, and are convinced of a yield retarding effect. New research by Doctor Don Huber of Purdue University helps to explain how this might be possible.

Huber’s Bombshell

Dr Huber is a microbiologist who decided to look a little deeper at how glyphosate affects soil-life. He was the first researcher to discover that this popular herbicide has a major impact upon two specific groups of organisms. He found that glyphosate kills the sub groups within the soil responsible for the delivery of iron and manganese into the plant. In fact, in one study he found that if a mere 2.5% of the spray solution made direct contact with the soil, it served to reduce manganese uptake by 80% and iron uptake by 60%. The loss of manganese-reducing organisms obviously lowers the levels of manganese in our food and may have health implications for humans (Chronic Fatigue Syndrome) and livestock (reproductive issues). Iron is already the most serious mineral deficiency in the developing world. Dr Huber also found that glyphosate could tie up other soil minerals including copper, magnesium, and zinc. He found that the herbicide could lock up nickel in the soil. Nickel is required to activate the urease enzyme that allows utilisation of urea. Dr Huber’s research revealed that residues of this “safe” herbicide could remain inactive in the soil indefinitely and that the addition of soluble phosphate can reactivate the inert form. He also found that these residues could bond with gypsum in the soil.

Link to Spontaneous Abortion

US research found that glyphosate was directly linked to spontaneous abortion in mammals and that Roundup was more likely to create this response than the generic products. It is assumed that the cutting- edge adjuvants that increase the efficiency of Roundup also increase some of the glyphosate negatives. Sometimes the adjuvant can actually be worse than the chemical they are boosting. Research by Peluso et al, for example, showed that it was the adjuvants rather than the glyphosate that were responsible for genetic damage following herbicide contact. There is also evidence that glyphosate may be an endocrine disruptor.  In vitro studies have shown that glyphosate affects progesterone production in mammalian cells and can increase the mortality of placental cells. Glyphosate is particularly damaging to amphibians. In fact, it may be the biggest frog-killing farm chemical.

Resistant Super Weeds

Australia was the first country to report resistance to glyphosate when it was found that ryegrass was no longer killed by the chemical in Orange in NSW. Farmers associations around the globe are now reporting 103 subtypes and 63 weed species with herbicide resistance. The use of genetically modified Roundup Ready crops has seriously amplified the issue of resistance. In fact, it is the growing problem with resistance and associated superweeds that has seen Monsanto share prices slump in recent months. GM supporters argue that there has been a reduction in the use of heavier chemicals associated with the introduction of Roundup Ready crops but this may not continue as the increasingly resistant superweeds are leading to a return of some of the worst of the herbicides (like Paraquat).

Solutions to Increase Yield and Herbicide Sustainability

How do you know if you are suffering from glyphosate persistence in your soil? Well if you have used glyphosate for years and you are not seeing increases in pest pressure, falling yields and early maturity, then it may not pose a problem for you. You may have the soil life or the soil type to neutralise potential problems. However, if you think you should be doing better, there are a couple of good options. You can trial a complete, chelated trace mineral mix as a foliar and gauge the reaction. If there is a pronounced response, it could signal trace mineral inhibition in the soil, linked to glyphosate persistence. It could also signal nutritional neglect, of course, but this could be further investigated with soil and leaf tests. I admit that I’m biased but I truly believe that the best chelated trace mineral mix on the market is Shuttle Seven™ from NTS. This liquid fertiliser features particularly high levels of iron and manganese, the minerals most affected by glyphosate persistence. If the minerals are in the soil but not making their way into the plant then perhaps glyphosate is doing more than just killing your weeds. The question then becomes, “how do I rid myself of these residues?”.

A strategy that has proven very effective in Europe involves a heavy application of fulvic acid to the soil. This involves the application of 3 kg of NTS Soluble Fulvic Acid Powder™ (the equivalent of around 20 litres of liquid fulvic acid) per hectare. Fulvic acid has a remarkable CEC of 1400 and it can bond to contaminants in the soil and sponsor their biodegradation or leaching. Proponents of this approach also claim sensational root growth in pasture and crops following this large application. Fulvic acid is a recognised promoter of root growth.

The other strategy to increase the sustainability of herbiciding involves an additive to the spray tank that speeds the degradation of the glyphosate, ensuring that it does not become a yield reducing liability. NTS has developed an outstanding herbicide detox agent called Herbi-Safe™ that is now widely used in horticulture and broadacre to avoid glyphosate persistence.

In Conclusion

Glyphosate is a prime example of how conventional agriculture can be seen as a self supporting, unsustainable system. Since 1996, US farmers have applied over 2 million kg of glyphosate that they would not have applied had they not converted to GM crops. The glyphosate may be reducing trace mineral availability, reducing yield and increasing pest pressure. Research has shown that this insidious chemical also kills nitrogen-fixing organisms and earthworms so you do not receive the multiple benefits conferred by these creatures and you are more tightly bound to the chemical treadmill. Consider a cleanup of your soil. Trial a small area and you may be pleasantly surprised.

Please call NTS on +61 7 5472 9900 or contact us for free agronomic advice.

Tags: glyphosate, roundup

This entry was posted on Friday, February 4th, 2011 at 9:48 am and is filed under Biological Agriculture. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site. Disclaimer: Any recommendations provided by Nutri-Tech Solutions Pty Ltd (NTS) or its Distributors are advice only. As no control can be exercised over storage, handling, mixing application or use, or weather, plant or soil conditions before, during or after application (all of which may affect the performance of our program), no responsibility for, or liability for any failure in performance, losses, damages, or injuries (consequential or otherwise), arising from such storage, mixing, application, or use will be accepted under any circumstances whatsoever. NTS recommend you contact an Agronomist prior to product purchase and application. The buyer assumes all responsibility for the use of any NTS products.