Roundup ready crops and their impact on organic matter ratios

[Sorcerer]

I'm being lazy and don't want to do any research, but it occurred to me while thinking of possible long term consequences of Round up ready monocultures, that the type and ratios of organic matter, which would normally be left on a field after harvest and dug back in before replanting would vary significantly from the traditional farming practices, which use less efficient methods of removing weeds.

Let's take Maize as an example, it obviously has its own nutrient profile, carbon and nitrogen ratios are very important when determining efficiency of composting and returning usable nutrients to the soil. Keeping the amount of carbon down and the amount of nitrogen up is important, traditionally fields are rotated with a legume crops being grown and dug in between harvests. If there is a lesser ammount of weeds in a feild, which I assume is the result of round up ready crops, then there is going to be a different nutrient profile and different ratios of carbon to nitrogen. Weeds tend to be herbacious, and thus higher in nitrogen than maize, weeds also include legumes which fix nitrogen.

And that's just the carbon and the nitrogen, different plants have different efficiencies in the ability to uptake other nutrients, when they return to the soil, those nutrients are available in a different form, which may be easier for other crops to use. So a variety of plants while also competing for nutrients can also ironically then aid other plants in the ability to utilise them.

Local fauna is dependant on types of flora available, how do these mono cultures impact the types and variety of animal species which via consumption, defecation and death, are part of the cycle which returns organic matter and nutrients to the soil? Assuming a reduction, or atleast an alteration in species diversity, how does that in turn effect the nutrient profile of the soil? (This would also be a pertinent question with regards to BT crops, which directly kill insects, perhaps, since they are an input to the system, with minimal loss via consumption, BT crops would actually have a positive effect on organic matter in this way. But I digress.)

Soil fauna and microbiota is influenced by nutrient availability and organic matter content and also predation and other relationships by above fauna. These help to recycle nutrients and influence soil environment, which subsequently also effects nutrient availibility to crops. The nitrogen cycle being a prominent example.

I was wondering if there is any research into how round up ready monocultures influence soil communities and subsequently their effect on soil fertility?

Assuming there is a significant negative effect on soil fertility:

From a simply economic viewpoint. How much are the benefits gained by profits from increased yeilds offset by costs in the requirement for applying additional fertilisers?

From an environmental viewpoint. What would the increase in carbon dioxide emissions be with the need for added fertiliser? What could be some long term consequences for soil ecosystems, species diversity and how would it effect that ecosystems ability to return to its original state?

In America, are these kind of long term and deep reaching effects required to be researched and indentified for cost benefit analysis before release of a GMO into the environment for commercial use?

Thanks for reading, your time is appreciated, if you'd care to comment your input will be appreciated.

http://www.google.com/url?url=http://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download%3Fcid%3Dnrcs142p2_052823%26ext%3Dpdf&rct=j&frm=1&q=&esrc=s&sa=U&ei=oX5YVd3iF5Tf8AWt9YGwAw&ved=0CBkQFjAA&usg=AFQjCNGNRSS1jF7RGoekDmm-0nGKA_WGhg

http://en.wikipedia.org/wiki/Carbon-to-nitrogen_ratio

Finally overcame my laziness and googled it, looks like I've got some bed time reading, it will surely put me to sleep.

http://www.monsanto.com/newsviews/documents/cpu_roundup_ready_crops_glyphosate_and_micronutrients.pdf

However this doesn't address the macronutrients, specifically the C:N ratio.

Edited May 17, 2015 by Sorcerer

[Endy0816]

Actually the Haber-Bosch process makes it extremely easy to fix our own nitrogen. Takes nitrogen gas(78% of our air), a fairly small amount of energy and natural gas resources(single digits for both of the last two) in exchange for effectively removing the major limit on plant growth.

 

We are presently having the opposite problem, we are fixing far more nitrogen than ever occurred naturally. The fertilizer isn't being completely utilized and is ending up in the ecosystem.

 

The flip side is that without it, we would need more land under cultivation or more people would be starving. Likewise at least some portion of government policies would have continued to revolve around control of guano supplies. Depending on how bad the situation became, this could have been cause for war(again).

Edited May 17, 2015 by Endy0816

[John Cuthber]

" fairly small amount of energy and natural gas resources(single digits for both of the last two) "

I suspect that one or two percent of the world's energy use isn't what most people would call "small". I agree it's much smaller than, for example, transport, but it's still a lot.

 

However, back at the topic. There's nothing to stop someone using alternating Roundup ready maize and alfalfa for example.

[Sorcerer]

@Endy: Yes, we can produce our own fertiliser, but if we need to replace nitrogen when otherwise we wouldn't, we are fixing a problem we might not need to cause. I guess if it's cheap enough, then the economic question might not be significant, however what about the environmental one?

@John Yes, and it is common practice to alternate crops, I mentioned that "Keeping the amount of carbon down and the amount of nitrogen up is important, traditionally fields are rotated with a legume crops being grown and dug in between harvests." But, all things equal, the roundup ready crop still suffers a loss during cultivation, it might not be significant, since when the C:N ratio is restored to be favourable the organic matter can break down, but there still is a difference in C:N ratios for a period of time.

Carbon and nitrogen were used to highlight one way round up ready monocultures, which are even more uniform than conventional monocultures, might disrupt nutrient cycles by altering species diversity in soils and around the field. Ecosystems are complex and reduction in one area can cause imbalance in other areas, it may alter the microbiota in a way that the effieciency of various food webs which leave available nutrients for plants is disrupted.

It just seems odd to me that we would want to add things back to a system when we could prevent the need to.

Anyway, the major question was "I was wondering if there is any research into how round up ready monocultures influence soil communities and subsequently their effect on soil fertility?" I'll go back and highlight that.

Edited May 17, 2015 by Sorcerer

[Endy0816]

" fairly small amount of energy and natural gas resources(single digits for both of the last two) "

I suspect that one or two percent of the world's energy use isn't what most people would call "small". I agree it's much smaller than, for example, transport, but it's still a lot.

 

all depends on what you consider alot

 

That's the estimated value, but we're using natural gas for the hydrogen which we could be burning instead. I'd wager its at least a bit higher in terms of opportunity cost.

 

 

@Endy: Yes, we can produce our own fertiliser, but if we need to replace nitrogen when otherwise we wouldn't, we are fixing a problem we might not need to cause. I guess if it's cheap enough, then the economic question might not be significant, however what about the environmental one?

 

To support the population levels we have, natural means are not typically thought to provide enough. We'd need to look at either reducing the population or increasing the amount of land given over to crops.

 

If it makes you feel better, we will have to switch eventually to more sustainable methods. Phosphate is the other side of the coin. We can't pull it out of the air like we do nitrogen. As sources are mined out, we'll be stuck with ensuring a sustainable loop.

 

[overtone]

 

 

I was wondering if there is any research into how round up ready monocultures influence soil communities and subsequently their effect on soil fertility?

The practice of large scale monoculture itself, rather than anything specific to using megadoses of glyphosate rather than some other herbicide, would be the primary influence and long term problem. The impact of machinery even - the compaction of the soil - would have more influence than the herbicide chosen, at least until one gets into the more poisonous brands that will become necessary when glyphosate has been ruined by current GMO methods and practices.

 

It's also possible that no till techniques, fostered by the glyphosate GM (although not exclusive to it or GMO tech in general), would improve soil fertility over time in comparison with plowing. Again, minor in a context of large scale industrial monoculture.