Episode 297. Living Mulches

This is The ChangeUnderground for the 2nd of May 2022.

I’m your host, Jon Moore

Decarbonise the Air, Recarbonise the Soil!

This week I dive more deely into a living food production approach.

Living mulches have been a thing for a long time. Using them requires a slight shift in emphasis and approach. It is not always worth the effort.

In an article from the University of Wisconsin-Madison entitled: Living Mulch Suppresses Weeds and Yields in Organic Vegetable Plots

Quote:

Researchers at the UW-Madison tested living mulches for use in the production of three organic vegetable crops to evaluate their impact on weed suppression, labor needs and crop yield and quality. The results demonstrated that, while the living mulches did appear to suppress weed populations, they also resulted in lower vegetable yields. The living mulch plots in this study also had higher labor requirements than the control plots.

End Quote

Now this is instructive. I’m in the process of setting up a living mulch garden for blue corn production next summer. We’re in the last month of autumn at present. It has been a strange, very dry, autumn for this part of the world this year. From the reading I’ve done, a ten centimetre strip through a field of clover on 1 to 1.2 metre centres does not appear to reduce yield or raise labour costs but then again, blue corn, a maize variety, is hardly a typical vegetable crop. The varieties planted in the paper cited were snap beans, capsicum and broccoli. 

I can understand the beans not benefiting especially from a leguminous living mulch, they’re already legumes. The capsicum and the broccoli required some thought. The growth habit of the maize plant is different from that of those vegetables. What happens with the maize is this: it gets away nicely before the clover can over grow the cultivated or sprayed strip. As the maize grows it shades out more of the clover, the clover releases its nitrogen and the maize kicks again and so on. Once the maize is harvested, sufficient remnants of the clover remain to quickly cover the soil after the stover has been removed, either mechanically or by grazing.

A quick check of the paper cited reveals:

Quote:

Researchers recorded the living mulch stand density four weeks after seeding and clipped the mulches prior to vegetable planting in early June. There was no clean cultivation around the vegetable plants in the living mulch.

End Quote

And there you have it. By not giving the capsicum and the broccoli, as transplants, a bit of breathing room to be established, they were competing rather than making use of soil biota to care for each other’s roots. Added to this was the process of pushing a lawn mower over the mulch between the plant rows between four and six times during the season. The living mulch used was also a bit of a puzzle: buckwheat, field pea, crimson clover and medium red clover. I can understand the idea of diversity but cut buckwheat will not grow back much, field peas are an aggressive cultivar and the clovers whilst annual should have been sufficient.

I think, from what I can see in the article and other pieces I’ve read, on the maize for instance, that this particular form of living mulch was not well suited to these vegetables. The experimental design called for way too much interference in the system by humans and the experiment ran for just two years. I would have thought a build up of material from continual mowing would improve soil organic matter but it turns out the test plots were ploughed each spring to restart the measured process from the same bare soil starting point. 

This tells us we need a longer term test for these things and that I should try some broccoli transplants into narrow minimally cultivated strips in a white clover living mulch, just to see. Another case of “mess about and find out” that is the scientific method.

The other lesson is to read the whole article and to think critically about both the article and the methodology used in the reported results.

Now before I receive a large boot up the date, I have a confession to make. I’ve said “my reading” but that’s not exactly truthful. I have spent much time watching YouTube videos. The very thing that can lead to bizarre statements from the untrained. But let me be clear, the videos I’ve relied upon to make the decision to grow a mixed variety of white clovers have been from tertiary educational institutions. A white clover living mulch is also a thing recommended by Masanobu Fukuoka, so I’m secure in stating this path is one backed by evidence based research. It’s why the title of the cited article had me puzzled. It seemed in direct contradiction to everything I’d read/viewed. As you can see, I hope, from the above, the system used in the methodology is sufficiently different from a clover based system to explain the differences.

All that being said, I have another article from an ametur, so to speak entitled: 6 Reasons Why I Chose Clover as a Living Mulch by: KANE JAMISON.

Quote:

  1. Less Weeding
  2. Retains Moisture 
  3. Withstands Traffic
  4. Nitrogen Fixer
  5. Improves Soil Tilth
  6. Attracts Pollinators

End Quote

Which are six pretty good reasons to try the idea. 

I’ll also be using rabbit tractors followed by chicken tractors, at least on the borders of the areas I’m sowing to clovers. I’m even contemplating setting one portion aside, say 300 m2 to see if the living mulch could work as the basis for a larger rabbit/chicken enterprise on the site. The results won’t be in for twelve months but I’ll let you know how it goes.

As I mentioned in last week’s episode, The Great Dying, I think we are in dire strife in regards to GHGs. I think and much of my reading seems to confirm, a multilayered, continually growing vegetative soil covering will actually draw down more carbon than a set of single species, rotated garden beds. These, if grown organically, are better than a chemically doused similar system. It’s all about getting to the point where we can make the biggest impact we can and produce as much food as possible from as small an area as possible. If we can produce the same amount from half the space by species stacking, then we leave more space for a wilder form of Nature.

We all need to get onto this. We can start where we are and begin with what we have on hand. Plant, plant and then plant some more!

So if you’re not yet growing and would like some guidance, the discount is still on for the No-Dig garden Course over at World Organic News. It’s currently selling for $17 dollars not the usual $149 until the world starts to return to a little more normality. 

So if you have been put off in the past, now is the time to jump in and learn. If you know anyone would be interested and the more people we can get growing the better, please let them know. I’ll have a link in the show notes or you can go to the World Organic News.com website and click the course tab. Please spread the word, we need to get as much food happening as possible as close to the people eating it as we can. The best time to move from consumption to production was probably 50 years ago, the second best time is now.

Decarbonise the air, recarbonise the soil!

Thank you all for listening and I’ll be back next week.

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LINKS

No Dig Quick Start Course

https://worldorganicnews.com/courses/no-dig-gardening/

buymeacoffee.com/changeug

 

email: jon@worldorganicnews.com

 

Facebook Page: https://www.facebook.com/groups/1546564598887681

 

Living Mulch Suppresses Weeds and Yields in Organic Vegetable Plots (CIAS Research Brief #100)

https://cias.wisc.edu/organic-initiative/living-mulch-suppresses-weeds-and-yields-in-organic-vegetable-plots-cias-research-brief-100/

 

6 Reasons Why I Chose Clover as a Living Mulch by KANE JAMISON

https://insteading.com/blog/white-clover-as-a-living-mulch/

 

Episode 296. The Great Dying

https://worldorganicnews.com/episode296/

 

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