Inside View: Latest Dirt on Root Zone Management

The Latest Dirt on Root Zone Management
March 13, 2017
Written by Gary Jones
March April 2017 – I write this a couple of weeks before his inauguration, and president-elect Donald Trump is in process of picking his cabinet. He’s done Education, Transport, Energy and, of course, all the military/security positions. In fact, he’s done all cabinet and senior advisory positions except for two. Right, he’s down to the last two and at this point, and he’s not appointed anyone to hold the Agriculture portfolio.1 (In case you’re wondering, the only other outstanding vacancy is Secretary for ‘Veterans Affairs’.) Firearms before food is such an interesting concept, don’t you think?

With Scott Pruitt, Donald Trump’s pick to head the U.S. Environmental Protection Agency, climate is firmly in the hands of a successful lawyer who has spent years fighting the EPA and (pretty much) all that it stands for. So I was pondering where this leaves another non-renewable resource that rarely (if ever) gets a political mention, or at best in some quarters is seen as a dirty four-letter word: soil. Given the comments in the intro paragraph above, it’s clearly not high on the agenda of the incoming U.S. administration.

As growers, we’re used to monitoring our growing media, be they soil-based or inert, man-made alternatives. In various scenarios, we check pH and EC (daily in many cases), individual nutrient levels, heavy metal content, temperature, AFP, CEC, water-holding capacity and oxygen levels, drain-down times and wet-up times, organic matter content and occasionally even biological activity. We are clearly familiar with the philosophy of “you can’t manage what you don’t measure,” and so spend much of our managing by doing lots of measuring. Invariably, our sampling methods are almost always destructive.

Some argue that we need non-destructive methods for determining the condition of growing media, soil health status in particular. To that end, two nutrient/soil management projects recently received federal U.S. grant funding: “the U.S. Department of Energy’s ‘Advanced Research Projects Agency-Energy’ (ARPA-E) has awarded $4.6 million to Lawrence Berkeley National Laboratory (Berkeley Lab) for two innovative projects … giving farmers important information to increase crop yields while also promoting the storage of carbon in soil.”2

Researchers say that, “one project aims to use electrical current to image the root system, which will accelerate the breeding of crops with roots that are tailored to specific conditions (such as drought).”2 The other project will develop a new technique to measure the distribution of carbon and other elements in the soil.

The lab received these awards from a program that seeks to develop crops that take carbon out of the atmosphere and store it in soil. They claim this enables “a 50 per cent increase in carbon deposition depth and accumulation while also reducing nitrous oxide emissions by 50 per cent and increasing water productivity by 25 per cent.”2 I’m wondering if this last point (increased efficiency of water use) may actually be the most significant piece of this.

Carbon sequestration in our soils may offer a long-term climate change contribution, particularly as (according to the University of California) soil carbon deficits are now globally common place.

There has been much comment recently about the effect of a carbon tax on the greenhouse industry. And rightly so. Maybe we can develop ways to put carbon into our growing media for long-term storage for the benefit of everyone. Link this to a financial payback from government and we have a real incentive for growers to develop better ways of root zone management for another variable. (As long as it doesn’t make us use more carbon as we feel absolved of our responsibility to use less!)

Interestingly, the money for the projects at Berkeley is coming from the U.S. Department of Energy. Agriculture therefore clearly has some long-term significance to at least one of the people in power in the US. Until next time.

1 BBC News at, 9th January 2017

2 University of California press release, sourced in

Gary Jones is co-chair of horticulture at Kwantlen Polytechnic University, Langley, B.C. He serves on several industry committees and welcomes comments at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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