Plant roots are receiving more attention of late and well they should. Roots are the foragers that deliver water and nutrients to the plant, but too often our attitude is “out of sight, out of mind.”
With the current interest in many plant species, cover crops and soil health, much of it comes down to what happens with roots. We hope soil health enthusiasts will enjoy seeing the anatomy of the roots that feed the plant and maintain the soil.
The mycorrhizal fungi in the rhizosphere (the area next to the root) play a big role in getting nutrients to the plant. Our switch to zero till has allowed them to flourish. Our University of Saskatchewan is embarking on a big program to learn more about how roots do their thing and how we might intervene to the plants’, and our, advantage. Much of that is “inside” work — learning about how the plant roots and soil organisms interact in artificial systems.
It makes sense to me that we should know something about how roots grow in natural, outdoor, systems before doing the close up work. A lot of good work has been done in this area.
The reader may wonder why I talk about work that was done before I even entered university and by folks that have been pushing daisies for 60 years. Read on and find out! The information is “old enough to be good” and no one is doing such work today.
The big actors in documenting the big picture, the gross anatomy of roots and the physical nature of crop and native plant root systems were Pavlychenko and Weaver. Since their work from the 1920s to the 1950s, no one has even come close to what they did, except for the Austrian connection.
Thomas K. Pavlychenko, 1892 to 1958; University of Saskatchewan 1930 to 1948.
By far the best work on gross root anatomy was done by T.K. Pavlychenko at our very own College of Agriculture at the University of Saskatchewan. Pavlychenko developed a unique method of studying the details of plant roots to their entire depth. It involved a lot of physical labour. He dug all around a big block of soil, removed the block in one piece, washed the soil from the roots and made mounts of it all. The root washing was what made his method unique.
There is actually a silent movie that shows it all. Thanks to Steve Shirtliffe of our plant sciences department that movie has been digitized and is available at the click of a mouse (find it here on YouTube).
Pavlychenko prepared many complete mounts of entire root systems. A mount of a two-year-old crested wheat grass plant goes to a depth of eight feet. It is a grand piece of work. It can be viewed on fourth floor of the Agriculture Building at the University of Saskatchewan but it is hard to photograph. Pavlychenko made many such mounts that are now scattered around Western Canada.
It was Pavlychenko’s dream to complete a root-study museum which would preserve the great root mounts he had assembled. But alas, university bureaucracy got in the way and it never happened (that is my interpretation of the readings I have done on the subject).
Pavlychenko did his PhD with John E. Weaver of the University of Nebraska who spent a lifetime working on roots of native and crop plants of the Great Plains region of North America.
John E. Weaver 1884 to 1956; University of Nebraska 1915 to 1952.
John Weaver spent his working days at the University of Nebraska and specialized in grassland species but also did great root work on crop plants. Some of his early work was published by the Carnegie Institute for Science in Washington. I have communicated with them in penning this piece. They were very responsive and helpful, and there is much useful information on their website (find it online at carnegiescience.edu).
A quick Google search of J.E. Weaver, Nebraska, reveals his complete works in PDF format from the University of Nebraska.
Weaver used a different technique than Pavlychenko. He also dug deep trenches next to the plants but did not excavate, wash and mount. He painstakingly exposed the roots with a sharp instrument and then prepared sketches of root systems that produce easy-to-reproduce photographs.
In addition to the journal articles and the Carnegie Institution pieces, Weaver wrote two books published by McGraw Hill: Root Development of Field Crops and Root Development of Vegetable Crops, both available with the click of a mouse.
Weaver’s swansong was two complete books:
- North American Prairie, Johnsen Publishing Co. Lincoln, Nebraska, 1954. (This was re-published in 2012 by Literary Licensing, LLC.)
- Grasslands of the Great Plains: Their Nature and Use, with co-author F. W. Albertson, Johnsen Publishing Co. Lincoln, Nebraska, 1956.
The second book has a chapter on “Canadian Mixed Prairie.”
The Austrian connection
While at the U. of S. library looking for books on roots I stumbled on a book written in German by one Lore Kutschera (1917 to 2008).
Now, Kutschera just happens to be my wife Inga’s maiden name so my ears perked up. Her folks emigrated in 1939 and settled at Loon Lake, Sask. In her early years German was the language. With her translation help, the title of Kutschera’s book is something like Root Atlas: Central European Field Weeds and Crops. This book has dozens of very good diagrams of root architecture of plants grown in the field.
In his reference list Kutschera had many Weaver references and his field diagrams suggest he used the Weaver method to get the information.
In the next issue we will bring you a number of examples of what plant roots look like when growing in actual field situations. What I have found interesting in all the reading and looking at plant roots is that the detailed work fits well with what I have observed over 40+ years of using a backsaver soil probe to get a sneak peek at a very small portion of the roots that feed our plants.
In this issue we will provide a couple of examples. The first example is for sugar beet growers in the Taber, Alberta, area. We often think of sugar beets as just the beet itself but the roots can go to five feet.
Weaver went on to say that when roots encounter an area enriched by previous roots or earthworm burrows they also branch out.
Our second example is closer to home and shows wheat duking it out with wild mustard. The plants would have been grown on the U. of S. campus. No wonder 2,4-D was such a game changer.
This is Part 1 of a series. I’ll have more to say about roots and root networks in our April 25 issue of Grainews.