Monday, August 30, 2010

Organic Agriculture, Post 1 - Herbicides

When consumers shop at the grocery store, does organic equal sustainable or is it just a heavily regulated marketing tool ? I think the answer is that it can be some of both, depending heavily on a whole bunch of extraneous factors. There is no possible way I can do justice to this topic in one post, so I'll probably spread my musings across a whole bunch of posts, as I have done with other topics on this blog.

The focus of the first several posts will be on exploring some non-organic technologies, and touching on some of the reasons why people (especially farmers) use them! I want to talk a little bit about herbicides for the remainder of this post.

When I was a child in the 1970's there were next to no chemicals registered for use to control weeds in navy beans, which are a very fussy and sensitive crop. The fields had to be mechanically weeded with a combination of inter-row cultivation and hand hoeing, and they had to be kept nearly weed free all season long as seemingly every weed in the world would either contaminate or stain the navy beans, resulting in a huge dock at the elevator. As such, the job was necessary, but goodness me it was hot, boring, mindless and extremely labour intensive work. It's also interesting to note that while the hoeing was pretty environmentally benign, inter-row cultivation brought it's own set of problems. Soil by it's nature is meant to be covered in either vegetation or residue. Inter-row cultivation removes the first and incorporates the latter, thus leaving the soil very vulnerable to erosion by wind and rain. Anyway, back to the program at hand....

To convey how much I and every other sane human being detested this task, I want you to imagine going out on a 90 degree day to hoe all the weeds out of your garden, however big or small it may be. Then I want you to transpose that pleasant task over to a field of navy beans by imagining that your garden consisted of 250 rows of vegetables and each row is choked with weeds and is 1500 feet long. If you could do 10 of these rows in a 10 hour day you would be besting anything I was ever able to do. So to hoe this field would conservatively take one person an entire month of labour. I also want you to imagine that once you got done hoeing this monstrosity the first time you would almost certainly have to turn around and start again, and I want you to imagine doing this all season long, from early June through mid September. Hoeing navy beans might not have been the worst job on the farm, but it sure ranks right up there in my opinion. Even better, navy beans were never lucrative enough to PAY someone to hoe them, so this task always fell on familial small humans.

So imagine everyone's wonderment (especially mine) when the first set of herbicides was licensed to be applied to navy beans. At nearly $ 30 per acre, the herbicide was expensive, but compared to the labour required to hand hoe the crop, the cost was a relative bargain, and the entire summer's labour could be freed up, minus the few hours on ONE DAY that it took to apply the herbicide.

Apply this thought process and cost vs. labour savings toward every other row crop grown in North America before World War 2 and it is extremely easy to see why the ineptly named "Green Revolution" took off with amazing rapidity upon the advent of 2,4-D herbicide in 1943.

In some respects, I genuinely like the idea of being and becoming a fully organic farm. I could easily satisfy the elimination of herbicides on the cattle side of the business through the use of management intensive grazing. Due to grass management constraints, maintaining reasonable pastures with the total elimination of herbicides on the horse side of the business would be considerably more challenging. It's my thought that it would be even more challenging in row crops.

Many small vegetable growers and even some row crop farms are already there. Unfortunately the number of farms is not very high and the acreage they control is also quite low. There are a lot of reasons behind the low acreage devoted to organics, but I have to believe from a practical standpoint that the biggest roadblock is labour. There are still too many farmers my age and up who remember summer days endlessly filled with hand hoeing, and we just aren't that eager to repeat them. Until something in the labour vs. herbicide cost equation changes (as I am sure it will), my goal on this farm is to minimize, rather than completely eliminate herbicide usage.


SmartAlex said...

Organic farmers have my respect. I can control my own garden, but I can't imagine doing it on a large scale. Those weeds do grow right behind you.

Julia said...

Ahh, yes...those wonderful days, weeks and months spent in the fields with my brothers, sister and neighbour boys hoeing and hoeing and hoeing. And when those 40 acres were done, you just start all over again. Can't say I miss it!

Jason said...


I think everyone who farmed in Durham County remembers those days, and I've never talked to anybody that wants to repeat the experience ! The only job I ever turned down in my life was at Pingles hoeing vegetables when I was in high school. Walter never got as much early practice as the rest of us I guess !

Daun said...

Hello Jason. I know you are very busy, but I am desperately trying to learn more, and you have a knack for explaining things.

When you get a spare moment, can you talk about a couple of things:
1) Why horses won't work in an intensive grazing situation. I know you "host" horses for clients so maybe you have much higher standards than a private owner would, but is there something about horses' grazing habits that prevents their use in an intensive situation?

2) How can one use intensive grazing to build brand new pasture? Everything I have read is using intensive grazing to improve existing pasture or rehab "dead" pasture. I have recently cleared land and the pH is all over the place. It's been seeded, limed, fertilized and rested, but is there something I can do with controlled animal impact to build the soil? I have horses, goats, sheep, and possibly pigs to do the work but not enough land for a cattle operation.

Thanks so much! I have stockman's grass journal and read a ton of books, but the "devil's in the details" and I am having trouble putting together a plan which will improve my soil.

Jason said...


1. Yes, no and maybe. Horses have both upper and lower front teeth, allowing them to shear plants off at ground level, which quickly weakens them, whereas cows have bottom teeth and a pad on top, just like goats. Horses are also inclined to spot graze more than cows are, so when they find a good patch, they literally graze it into dirt. Soil doesn't like to be uncovered, so at the next rain, some of the seeds that perpetually exist in uncovered soil will sprout and begin to grow. Some of these may be species you want in a pasture and some almost certainly won't be. Too much grazing pressure, especially continuously, weakens pasture and destroys soil. The (very) basic precepts of grazing management are to create conditions conducive to vigorous grass growth. Once adequate moisture and fertility are taken care of, a plant wants to be stressed periodically (by grazing it down to 4 inches tall or thereabouts) and then left to rest for a relatively long period of time. Ideally, in MIG, 90 % or more of one's pasture is at rest (with animals fenced out of it) at any given time. This is easiest to achieve when one uses animals that behave well in relatively large groups where the animals are bunched pretty close together, have relatively low metabolic rates, and aren't fussy eaters. None of the above = horses, in my opinion.

2. Until there is a foot (!) of grass in your new pasture, nearly ANY grazing you do will be detrimental to that pasture's health because new grass plants are establishing a root system as well as CHO reserves. Once the pasture is growing well, the correct application of grazing pressure combined with rest will take care of thickening the sward AND fertilizing the pasture (with animal manure from the grazers).

Most neophytes and many long time farmers overestimate the carrying capacity of their pastures. Over the course of a grazing season, a NH pasture can produce anything from one to three tons of edible dry matter per acre depending on it's inherent capability and fertility (usually pretty low). If a grazing season is 150 days long, a three acre pasture might yield anywhere from 40 to 120 pounds of DM per day. Good grazing managers might be able to get animals to eat half of the available dry matter, so the pasture realisticially will yield 20 to 60 lbs dry matter per day. Figure grazing animals will consume 2 % of their body weight in pasture dry matter every day. Thus you could figure that every 1000 lbs of livestock (horses, cows or goats) will eat 20 lbs dry matter every day.

Did that help or are you just more confused now ? :)

Daun said...

Jason, thank you that is most helpful. I knew that horses were not rippers, but cutters and that was harder on the grass. Are sheep also not cutters? I guess just their lower biomass and better "herd-philia" helps. I know cattle are also ideal because of their cloven hooves and weight drive carbon deep into the soil. How to get cow-like conditions without the cow? :)

My grass has had full rest for a year, but it's been a drought year. I've mowed at 12" twice in the entire year, mostly to knock the weeds down. I am overseeding, liming, rinse repeat again this fall, but I was wondering if MIG would rehab the pasture faster. Methinks now I will get a good swarth "mechanically" and then add biomass.

I used similar calculations and got pretty much the same results you did. I calculated 1" of grass over 1 acre yields 300 lbs of "hay" and peak growth during a typical NH summer (145 days) is 1/2 " per day (a far cry from the dry Texas summers I am used to). I got pretty much the same results, a couple of horses and a couple of sheep/goats/turkeys/meat animals and I can keep everyone healthy/happy. Much more and I am in trouble. Which is fine, I am just trying to feed my small family, not run a business.

Thanks so much for "penciling" it out with me. I'm just reading and you're doing, so I really appreciate the insight.

Jason said...


You're welcome !

The main thing is to cut the grass repeatedly down to roughly four inches tall every time it gets ten or more inches tall. The more you do this, the thicker your stand. Whether you do it mechanically or with animals won't make much difference to the grass in the end.

One of the joys and challenges of farming is that every year is something, and none of them are "normal" ! After a lifetime of doing, I still get caught with my pants down far more often than I'd care to admit ! :)