Saturday, September 22, 2012

Kanapaha Prairie: Recalling a Legacy of Freedom

                                    Kanapaha Prairie: Recalling a Legacy of Freedom

Kanapaha is one of many ancient depressional prairies in North Central Florida. The largest and famous of these is, of course, Payne's Prairie, immediately south of Gainesville-- described extensively by William Bartram in the 18th century as "The Alachua Savanna".

One of my field site: Kanapaha Prairie (picture (c) Chris Wilson 2012)

 Bartram extolled this part of Florida as a landscape dotted by numerous such grassy savanna's, but dominated by pine savanna and mixed hardwood hammocks-- full of oaks, magnolias, hickories, wild citrus and so on. The Seminole Indians, descendents of lower Creek groups, moved into the area in the early 1700's, displacing the last of the Floridian tribe remnants (e.g. Timicuans) and the Spanish outposts that had earlier assured their demise through disease, and attrition. 

Hardwood Hammock adjacent prairie (picture (c) Chris Wilson 2012)

The Seminole thrived in this land of great abundance of wild game, birds and fish- replete with numerous freshwater springs and healthy, clear-running rivers. They became great cattle and horse people as well, herding the naturalized populations of these beasts originally introduced by Ponce De Leon in the early 1500's. Forage for their beasts was furnished primarily by these numerous savanna openings. These resources were supplemented by the grazing available in the open pine savannas, and the edges around the hardwood hammocks. Bartram described the horses and cattle as small and sleek- admirably adapted to the vagaries of this environment.

Cracker Cattle at Kanapaha (picture (c) Chris Wilson 2012)

The cattle shown in these pictures are "pure stock" of the "Spanish Colonial Cattle", otherwise known as "Cracker Cattle", the most direct descendants of the Seminole cattle, and a link to this cultural history. Like their forebears, they are small, horned, and hardy animals. They calve easily without assistance and their mothering instincts are strong and effective. These beasts know how to stay alive in a tough, predator-rich environment.

As the plantation economies grew in the Cherokee lands to the north, in Georgia, the political role of Florida’s Seminole territory became significant. They were a fierce, proud people- passionately devoted to their hard-won lands. Numerous African slaves began to escape their lot in Georgia and North Carolina, as the conditions of their chattel slavery became more brutal. Over the decades, a large population of these escaped “maroons” established themselves alongside the Seminole in North Florida.

Great old Live Oak (picture (c) Chris Wilson 2012)

Together, the maroons and Seminole hunted, fished, managed their lands with frequent fires, and practiced traditional polycultural field agriculture. The Seminole, too, sometimes practiced slavery, but the terms were ordinarily relaxed. “Slaves” were most often allowed to set up shop, marry, and profit from the proceeds of their own work- so long as they paid a moderate tax to their erstwhile masters.

For the span of a few decades, Florida was thus a potent symbol of freedom and resistance. For many, it represented the chance to create a new society and lead a dignified and free life. The US government’s war on the Seminole in the early-mid 1800’s stretched for decades as the joint resistance of the fierce Seminole and their Maroon allies proved difficult to overcome.

Whenever I set foot in one of these Prairies in my new home, I recall this legacy of freedom and resistance set amidst a tough yet abundant landscape.  For me, it symbolizes the enduring connection between human prosperity, freedom and the health of the land. 

Twin Live Oaks on Prairie (picture (c) Chris Wilson 2012)

Recommended Reading:

-William Bartram’s Travels. (Available freely online)

-Riordan, Patrick (1996). “Finding Freedom in Florida: Native Peoples, African-Americans, and Colonists, 1670-1816”. The Florida Historical Quarterly 75(1): 24-43.

-Mann, Charles (2011). 1493: Uncovering the New World Columbus Created. Knopf: New York.

Wednesday, September 5, 2012

Is organic food healthier than conventional?

The recent Stanford study has been duly making the rounds in the press. Despite the author's best intentions, there are now probably loads of folks running around telling each other that "organic isn't really healthier". Or wondering if it is worth the extra premium to buy organic. And to some degree, they are right!

Before we get all carried away, let's break this study down.

1) It is a meta-analysis review article, not a study with new findings. What they did was pull together about 237 previous studies, and attempt to synthesize findings. Of those, 17 involved actual human subjects being measured (for instance, for pesticide reside in urine). The other 220 studies were measuring various attributes of food, not its effects in humans. For instance, some of the studies looked at "bacterial contamination" whilst others assessed contents of vitamins and minerals.

2) The specific findings that stand out are these: a) "organic" food is not on average richer in vitamins and minerals than conventional counterparts, b) levels of microbial contamination are not necessarily lower in organic, c) organic foods lead to reduced pesticide exposure (which may even be under-estimated due to sampling methods).

What this just goes to show is that variation in farm management, and other on-farm and off-farm factors, override the significance of the "organic" label in determining the nutritional content of foods. I fully believe this to be true- and I thought so long before this particular headline. I've done Brix readings (a measure of sugars, amino acids, and other solutes in plant tissue-- thought to be a correlate of overall nutrient density, although this is a subject for a blog post in itself) on Cal-Organics salad mixes which scored so poorly as to be barely detectable. My refractometer was confirming my taste buds, that much of what is certified organic salad is really little better than water and cellulose nutritionally.

But here's the rub: reduced exposure to pesticides is still a great thing! We still know extremely little about how the long-term cumulative exposure to numerous different synthetic toxins affects vertebrates, particularly not for a human lifespan. The precautionary principle, and past track record of chemicals getting pulled from the market, suggests that we not risk it any more than is necessary.

Now, I don't have time to get into all the issues surrounding organic labeling. Let's just say it has pro's and con's. It is a provisionally useful label. Ideally, we'd like to know more about how a farm is run than whether it is certified organic-- other factors certainly are more important in predicting the healthfulness of the food that is produced. In fact, I personally take a nuanced approach to chemical fertilizers- I think they are sometimes useful, and not necessarily incompatible with sustainable soil management. The goal is a non-addictive use of fertilizing materials-- use them to secure abundant, healthy harvests, while still building organic matter long-term. Again, a future blog post in the works about practical soil fertility management and crop health and quality.

For now, don't buy into the headlines uncritically! This study is no justification for claiming that organic doesn't mean anything, and therefore isn't worth buying.

Tuesday, August 7, 2012

A Paean to Warm-Season Grasses

A follow-up to my previous post, on the drought. I took a trip down to Nichols Arboretum, a beautiful property run by the University of Michigan. They have a restored tallgrass prairie fragment there, called "Dow Field". For you botany nerds, it was first described by Henry Gleason as he passed by on the train on his way out of town (Ann Arbor).

Dow Field, like most tallgrass prairie, is dominated by C4 grasses, especially Big Bluestem (Andropogon gerardii).  I wanted to see whether my idea of having C4 (warm-season) grasses as part of a pasture base could be supported by a visual inspection here (i.e. am I just full of shit?).

What I saw was encouraging, although not quite as lush as it should be this time of year. When I read the site description for Dow Field a couple years ago, I recall it mentioning the soils were droughty- so there's  reason to believe that the grass would be even healthier in a better soil. But nevertheless, check it out:

Big Bluestem (Andropogon gerardii). Fairly typical of the exposed portions of Dow field.

I found a seemingly inexplicable clearing in a side portion of the field. There was a layer of dead grass, with younger growth of Big Bluestem, and lots of thistle. I suspect that the Natural Areas Preservation Program may have treated the area with herbicides earlier in the season to fight "invasive" (C3) grass.

A pretty prairie flower. Don't know what it is yet! 

The next photo shows my dog, Chloe, standing next to some fresh Bluestem growth. It was looking reasonably healthy, and would be at a good time to graze- still lush and vegetative. This gives me confidence in the warm-season grasses as providing valuable diversity and resilience for pasturage and hay. Imagine what this field would look like in a better soil, with more shade, and possibly flood irrigation...

Not far from the cleared patch, I shot this photo to show the awesome height of mature Big Bluestem. This was the tall-grass prairie that impressed the early settlers of the Middle West. It was a beautiful, diverse ecosystem, intergrading on the eastern front with oak savanna, and oak-hickory and mixed deciduous woodlands. These ecosystems sustained many herds of Bison, and numerous tribes of native Americans, adapted to the periodic vagaries of an intense continental climate. Indians burned the prairies annually to facilitate hunting drives, particularly in the fall (October-November). The immense heat and smoke from these fires so intimidated the early white settlers that they coined a term "Indian summer" to refer to the fire season

Chloe and the Big Bluestem 

I know the agriculturally-minded will scoff at my faith in the utility of the warm-season grasses for hay and pasture. It is true that, normally, their growing season is shorter, and the growth coarser and lower in protein than most of the introduced cool-season grasses (e.g. bluegrass, orchardgrass, etc.) Switchgrass is already well-accepted for this role south of Ohio. I'm not suggesting that, this far north, they should be the main basis of a pasture program. But I think that handled correctly, they could contribute mightily to resilience in the face of increasing climate vagaries. For comparison's sake, check out some local, similarly unirrigated cool-season grass:

Where's the nutritive value here? 


Saturday, August 4, 2012

Responding to the Drought

As I work on a longer post about livestock and methane, I wanted to say a few words about the unfolding drought catastrophe in this country.

2012 is officially one of the worst years on record for nation-wide drought. It is severely affecting the landscape- be it farms, ranches, or forests-- all around the country. I've been in Michigan these past couple of months, and the land here is parched. A combination of unseasonably high temperatures, very little winter snow, and spotty rainfall have combined to produce these conditions.

In SE MI (photo (c) Chris Wilson 2012) 

 Agriculture has been deeply effected. I'm told this is the worst year in memory for agriculture in the state of Michigan. The cherry harvest is hosed. The apple harvest isn't far behind. The corn and soy around here look patchy at best. Grass hasn't been growing (see post-script), so pastures are in bad condition, and hay prices have sky-rocketed. It's going to be a hard year for farmers, especially those with livestock and those in the fruit business.

 NOAA has recently released work directly connecting extreme weather events and (anthropogenic) climate change (see:, belying USDA secretary Vilsack's politically-motivated refusal to connect the dots between climate change and the current drought. Their models suggest a 20X risk for heat wave events in the coming decades compared to the 20th century.

Nevertheless, I want to point out that there is much that poor land-management has contributed, both in terms of drought susceptibility and in contributing to climate change locally, regionally and globally. Drought occurs as a function of effective, not total, precipitation. Effective precipitation is that which infiltrates into the topsoil, and is retained either for plant growth, or percolates to recharge groundwater flows and sources. Non-effective precipitation, by contrast, either runs off in the first place, or infiltrates the topsoil only to be lost through bare-ground evaporation.

Dry (C3) Grass

 The goal of ecological land management is to make effective precipitation approach total precipitation.

In turn, the key to this is management of the soil surface and the health of the topsoil. On both counts, conventional agriculture and ranching is a big fail. Arable monocultures are mostly bareground, subject to repeated tillage, and a barrage of chemical fertilizers, herbicides and pesticides. Heavy equipment compacts the topsoil, adding insult to injury. These factors cause depletion of organic carbon stocks and soil structure, decreasing infiltration and water retention capacity. In turn, this guarantees much higher rates of soil erosion, water runoff, and evaporative losses (a non-effective water cycle).

Without further elaboration, it should be clear that land management plays a big role in whether droughts develop, and, if they do, how severe they get. I'm not saying that rainfall isn't important- it obviously is, along with temperature- but it's a mistake to go into victim-mode and blame everything on factors outside of our control.

How to respond?

The first thing is we need to get a serious energy and climate policy. That means reducing personal consumption of fossil-fuel energy in all its guises, and investing in efficiency and renewables, both locally and federally.

Secondly, we need to get serious about land management- which means agriculture, ranching and, to some extent, forestry have to change in fundamental ways. This will mitigate GHG emissions by building soil carbon stocks, and foster resilience to drought, flood, wildfires, etc.

Finally, we should all look at ways of using water wisely, and investing in strategies to harvest and retain water (e.g. rain-barrels, ponds, keyline dams) in our landscapes.


A note on pastures: grass growth ceased this year for two main reasons, water stress and C3 physiology. C3 grasses have lower optima for temperature than do C4- plus are generally less deeply rooted hence more susceptible to drought. The combination of high temperatures and suboptimal rainfall caused extremely premature dormancy and senescence in our C3 grasses.

I suggest that farmers should look at setting aside 1/4 to 1/3 of their pasture-land into C4 grasses (Switchgrass and Eastern Gamagrass would be good choices), for hay and grazing. Although traditionally scorned by more northerly farmers, the Warm-Season grasses may play a big role in adapting to the 20-fold increased in heat wave risk forecast by NOAA.