A Pennycress for your Thoughts

How do you return huge swaths of vacant Detroit land to a productive use?  How do you deal with land littered with debris and poisoned by contaminated soils?  How do you return this land to a productive use?   These are questions I've been working on with a team of consultants on Detroit's eastside.

Vacant Detroit lots

According to Detroit Future City statistics, 20 square miles of Detroit's occupiable land is vacant. And according to a report by the C.S. Mott Group at Michigan State University, 7.6 square miles of this land is publicly owned.

More vacant Detroit lots

What if this land was converted back to agriculture?  What would you grow?  What crop would be the most productive? How could it serve as a catalyst for economic development?  For some, the answer lies in Pennycress.


Pennycress
image Credit: Wikipedia Commons

Most consider the arrival of Antoine de la Mothe Cadillac on the shores of the Detroit River in 1701 as the arrival of Pennycress in the new world.   Though its taken some 300 years, many now believe this European stowaway may prove to be the key to renewing Detroit's vacant land.

Below are my Top 5 reasons that make Pennycress the perfect urban farming crop:


Pennycress
image credit: Net World Directory

Reason #1: Phytoremediation

Phytoremediation is a process that use plants to remove toxins from contaminated soils.   It's a method that can be significantly cheaper than the typical "dig and haul" to a landfill technique.

Detroit has a three times higher rate of children with elevated blood lead levels than the national average. It is a primary toxin in cities because of its former use in paints and gasoline.  Urban studies have shown lead levels to be the highest along the perimeter of building foundations and within a few feet of busy streets.

• Pennycress is known as a hyperaccumulator of heavy metals.  As the plant grows, increasing levels of toxins are stored within the plant's roots and leaves.  These roots and leaves can then be removed along with the toxins they contain thereby decontaminating the soil.

Alpine Pennycress
(Thlaspi caerulescens)
image credit: Wikipedia Commons

Reason #2: The "Street Smart" Flower

Pennycress is especially adapted to survive in the harsh urban environment because...

• It is considered "native" to Michigan and will not act as an "invasive species".
• It is a winter annual, meaning that it can be planted in the fall (October).  It will lie dormant under snow during the winter and is harvested in the spring (May).  This allows an alternative crop, such as soybeans, to be grown during the summer months.
• It has the ability to grow in "marginal conditions", requiring very little if any pesticides.  This is particularly true because of the average low temperatures occurring during its growing season (fall and winter)
• It will only grow to an average height of around 2 feet allowing it to be planted near roadways without obstructing sight lines.

Biodiesel
image credit: Wikipedia Commons

Reason #3: Biodiesel

When pennycress is crushed, it produces vegetable oil (36% by volume) and meal.  The vegetable oil by itself can be used as a low temperature lubricant.  But more importantly, biodiesel can be produced from the oil through a process called transesterification. The process produces glycerin  (which is used in the production of soap) and methyl esters (the chemical name for biodiesel).
  
Pennycress produced biodiesel makes sense because...

• It performs at temperatures as low as -28 degrees Celsius (-18.4 degrees Fahrenheit).
• Unlike corn and soybeans, it is not a food crop and therefore does not compete with the world's food production. 
• It is ecologically friendly as compared to traditional fossil fuels (emits 78% less CO2).
• It works within the existing petroleum distribution network
• Biodiesel blends are warranted in most existing diesel engines and certified by ASTM.
• The energy yield per unit of input is 3.24 units versus 1 unit gasoline and approximately 1.35 units corn ethanol
• Its mileage per gallon is roughly equivalent to that of standard diesel fuel.

Animal meal pellets
image credit: Asico Group

Reason #4: Pennycress Meal

As mentioned earlier, when Pennycress is crushed it produces vegetable oil (which is used to produce biodiesel fuel) and meal.  Like other seeds in the mustard family, the meal is high in glucosinolates, which give mustard and horseradish its sharp taste.  Therefore the meal can be used as....

• A bioherbicide if the glucosinolates it contains are used in high dosages (an alternative to methyl bromide which is used in high value crops such as strawberries)
• A fertilizer containing about four percent nitrogen and 0.7 percent phosphorus
• An animal feed, though glucosinolate levels need to be monitored.  This is important to note because feedstock can account for more than 70% of the cost of producing biodiesel.

A biodiesel fuel pump
 (The "B" indicates the percent
biodiesel, i.e. B20 is 20% biodiesel,
80% petrodiesel)
image credit: Grow Pennycress

Reason #5: Job Creation

Because of how simple pennycress is to grow, it could serve as the spark that generates economic development in communities in search of new investment and job creation.  More specifically...

• Local residents can be taught to grow the plant.  
• Seeds require a very shallow planting depth meaning they can be spread by hand.
• Ongoing studies indicate that pennycress will produce a 35% higher earning per acre as compared to other oilseed and grain crops.
• Locally produced biodiesel fuel keeps the energy revenue within the community in which it is consumed

A vision for a new Detroit "Green Thoroughfare"
image credit: Robert Saxon, Jr. AIA

What's Left to Do

As promising as Pennycress appears, there still remain many hurdles.  Issues include:

• How vacant lands will be assembled into acreages that produce seed in volumes that will make biodiesel production profitable?
• Can a distribution network be assembled that integrates with the existing petroleum based system?
• Can biodiesel refinery equipment be assembled and made accessible to scattered pennycress farms?
• Can a system for training and maintaining land before, during and after seed production be developed?

Only with time, patience and effective experimentation, will Pennycress reach its potential as the urban homesteader's most profitable crop.

_____________________

Grow Pennycress, Arvens Technology, Inc.

Start Detroit, MetroAG Services

Pennycress: Up and Coming Low Break-Even Cost Crop for the Prairies, Start Detroit

Rolfe, G.L., A. Haney, and K.A. Reinbold. 1977. Environmental contamination by lead and other heavy metals. Vol.2. Ecosystem Analysis. Institute for Environmental Studies. University of Illinois, Urbana-Champaign. 112pp.

Singer, M.J. and L. Hanson. 1969. Lead accumulation in soils near highways in the Twin Cities metropolitan area. Soil Science Society of America Proceedings 33:152-153.

Schill, Susanne Retka , "Making Pennycress Pay Off", Biodiesel Magazine, January 17, 2008.