Agroecology from A to Z

Adventures in Agroecology and Food Systems


Biological soil disinfestation, Deliflor Chrysanten, Maasdijk, The Netherlands

At the 2013 GroSci conference this summer, full name: The International Symposium on Growing Media and Soilless Cultivation, I had a chance to tour the growing operations of some of the major players in the international floriculture world.  The Dutch are definitely not messing around when it comes to floriculture, in fact The Netherlands is the world’s largest exporter of ornamental plants and cut flowers.

At Deliflor Chrysanten, the world’s largest Chrysanthemum breeder, we learned about some of the challenges of growing in field soil under glass. Many greenhouses have cement floors and use soilless media to produce plants in pots, but some leave the soil exposed and use it for cultivation. With continuous cultivation of the same or similar crop on a single patch of soil comes a build up of pathogens, especially fungal pathogens that specialize in infecting that particular crop. Many of these fungal pathogens like Verticillium spp. can form resting structures in the soil that persist for long periods of time. What are your options as a grower in this type of production system?

1) Move the greenhouse to a different patch of soil (OK, not really an option because of the heavy up front investment in the greenhouse and land. High tunnels are designed to be moved…greenhouses, get out of town!)

2) Spray/ fumigate the soils with synthetic chemical fungicides (Effective, but carries an environmental burden)

3) Steam sterilize the soils in situ (Current method of choice, less toxic than fungicides, but carries a high fossil fuel cost and therefore a different kind of environmental burden)

4) Biological soil disinfestation

What is biological soil disinfestation? It is a technique developed separately in Japan and The Netherlands as a biologically based crop disease management strategy. The basic principle is that a carbon based substrate is added to the soil, then the soil is covered with an impermeable layer. Oxygen levels rapidly decrease in the soil as soil microbes consume the feast provided by the added organic matter. Anaerobic microorganisms become active in the soil in the absence of oxygen and contribute to the build up of compounds in the soil that are toxic to the resting structures of fungal plant pathogens (most likely organic acids). The tarp is removed and the soil is allowed to stabilize for a few days before planting while aerobic microbes become active again and the toxic compounds are degraded.

We heard from Henk Meints of Thatchtec who has been carrying out research and development for specialized blends of organic matter for use in soil resetting.


Deliflor Chrysanten greenhouse facilities in Maasdijk, NL
Satellite image from Google Maps

vrijdag deliflor-1216

Chrysanthemum transplants in soil
Photo credit: Paula van Ommen

vrijdag deliflor-1220

Soil covered for soil steaming process, an alternative to fungicide use
Photo credit: Paula van Ommen

vrijdag deliflor-1224

Chrysanthemum breeding plots
Photo credit: Paul van Ommen

vrijdag deliflor-1262

Blooming chrysanthemums
Photo credit: Paula van Ommen

A special thanks to Paula van Ommen for allowing me to use her beautiful photos of these farm tours.

Leave a comment

The Automat, no longer exclusively for fast food

While riding my bike back to Wageningen from a Phytopathology department lab outing to the nearby zoo in Rhenen, I almost fell off my bike when I saw this farm automat. Out by the road in front of the van Laar family’s Boerderij Welgelegen there is a unique sort of farm stand. This one is not on the honor system like so many road side stands in the US, but instead anyone with a hankering for fresh eggs, recently dug potatoes or farm-made jam feeds some Euro coins into the machine, punches in a code and retrieves their goodies. I was intrigued to say the least!


Family farm roadside automat, between Rhenen and Wageningen


Doors are numbered for purchasing choices like a vending machine

Automats have a long history in both the Netherlands and the US all the way back to the early 1900s. They are basically the same concept as vending machines, although for the hot snacks someone has to prepare the food and load it into the back of the machine. Belgium is working on a fully automated frittes (French fries, or should I say Belgian fries, with mayo) vending machine so hot food automats could become much more automated in the future. Both vending machines and automats sell almost anything you can imagine, I loved seeing the fresh bait vending machines in the Northeastern US that sold live worms for fishing. Besides being adorable and fun, automats have been in the food system news recently as many fear that the current struggle for living wages in the fast food industry in the US could create an incentive for more automation and eventually decrease employment opportunities.

Amsterdam train station

Modern fast food automat at Amsterdam central station


Vintage automat from the 1950s at the Openluchtmuseum in Arnhem
Caption translates to: The automatic vending machine is a Dutch invention from around 1900. The machines were used primarily for the sale of confectionery. In the 50s, machines were designed ​​for the sale of heated snacks.


I wasn’t kidding about the live bait vending machines! This one is at a gas station in Central NY.


I’m not sure what grass crabs are, but I’m sure fish must find them delectable



Typical US farm stand from the cabbage producing region of Western NY (Livingston County). It is on the honor system with a little box for you to put cash in.

Update: a fun video from Fans of Flanders on bread vending machines.


Leave a comment

Working windmills in the Dutch food system

Note: Today is the one year birthday of this blog. We’re almost at 5,000 views! A huge thanks to all of the readers out there who share an interest in sustainable food systems. In celebration, I’m starting a series of posts on the European food system documenting my adventures so far living in Wageningen, The Netherlands and working as a visiting postdoctoral researcher at Wageningen University.

This windmill, Molen de Vlijt, holds a special place in my heart, because it is the first windmill I’ve ever seen. I stumbled across it while taking a walk in my new town, Wageningen, this past winter. Built in 1879, the mill has survived lightning strikes, shelling in WWII and decades of neglect before being lovingly restored in 1979. This year happens to be the city of Wageningen’s 750th anniversary. I can’t wait for the special molenmarkt (mill market) this fall celebrating 750 years of milling for bread making.

Molen de Vlijt or "Mill of Diligence"

Molen de Vlijt or “Mill of Diligence”

750 years of milling

750 years of milling

The mill grinds regional organic grains and is open to the public on Saturdays. Being inside the mill while it’s running is almost like a steam punk space ship getting ready for lift off. The feeling of kinetic energy and the tremendous noise of the moving parts as the wind speeds up and slows down is very exciting.  I already knew I had a strong interest in traditional and modern food processing and preservation. I’ve toured Camas Country Mill in Oregon, and the historic Enfield Falls Mill in New York, but my experiences touring this mill have sparked a special interest in traditional wind technologies in the food system. Apparently I’m not alone, because there is an International Molinological Society that I just may have to investigate further. In this video, I take you inside the mill while it’s running from the ground floor to the fourth level. Here is a diagram of the inner workings of the mill as a guide.

Mill diagram from

Mill diagram from

Ready for baking!

Ready for baking!

Is it any wonder the Dutch are leaders in modern wind technology? Neeltje Jans, Zeeland province

Is it any wonder the Dutch are leaders in modern wind technology? Neeltje Jans, Zeeland province. And yes that is my Dad trying to push this wind turbine over into the North Sea!