Recent soil tests show that the amount of organic matter in the soil is increasing in some of the gardens, staying fairly level in others, and apparently declining in one of the gardens. This divergence is likely due to the management practices in the different gardens, but it could also be because of deficiencies in key nutrients rather than simply differences in the amount of high carbon material that is brought in.
0:00 Trends in soil organic matter
1:11 2023 test results
2:37 12 years of testing
4:41 Focus on the polytunnel
5:54 How much carbon?
8:01 Other nutrients sequestered
9:51 Nutrient deficiencies
11:37 Building soil
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31 Comments
Looks to me like you should switch all the beds to no dig, and then you'll have a single variable to compare: intensive, extensive, poli, etc…
Great content as usual. thanks for your amazing job. i'd love to see a very biochar intensive bed experiment along the years. or maybe more than one, making one adding lots of nutrients and another lazy one to show the do's and don'ts of it. i suspect that in the long term the "incorrectly" applied biochar catches up to the other one anyways.
great video as always thank you! i wonder, why do you plant the saplings on their side?
One of your best presentations. Thnx. This helped clear up a few answers to lingering sequestration issues I've been mulling over.
I'm outside my realm of expertise in the soil test world. But here are a few thoughts. I've heard it said, most soil has enough nutrients, it's the fact that they are locked in non-bioavailable forms. The conversion of these locked forms to bioavailable ones is conducted by bacteria that release all types of acids and enzymes. Thus adding rock dust, salts, and other inorganic compounds, doesn't really do much to make this more present, maybe just more proximal. Something like seaweed mill that comes from an organic source could be a solution, if you can identify something high in what you needs.
This leads me to think of cover crops and hyperaccumulators. Are they taking up from the soil, or are they more adapted to make certain nutrients available, directly or through symbiosis with bacteria. This seems like it has to be the case as pure sand or rock has no inherently bioavailable nutrients. And is slowly transformed by plants to fit their needs. It's strange how plants never seem to "run out" of nutrients in the wild. Only in home gardens. So my suggestion for cover crop is to find the research (there is an integrative tool / spreadsheet) for bioaccululators of the nutrients you are deficient in the most, and grow that specifically. The initial fear is that it will degrade the soil of those nutrients, but if you chop and drop and leave it in place. Similar to the old practive of fallowing. They should get recycled and not depleted. This is like moving money from a savings account to a current account. This is different from monocrop farms that Remove the harvest. Soil needs to be viewed as a bank account of many types.
This all leads to the arguments around the "liquid carbon pathway" that has been popular for a few years. They preach having plants in the soil at all times. This feeds the bacterial. And what are bacteria doing with this energy they are fed? I'm guessing they are Digesting rock and making nutrients. That's been preached before. But what I noticed in the video was that the polytunnel has had good increases. All else being equal, you do more growing in the tunnel than outside the tunnel. It has a longer season, and you do more winter crops. They simple garden, which is degrading, is the one covered over winter. I've heard other home gardeners anecdotal comments that their annual vegie crop does much better when planted in the soil around a perineal. That all seems to fit here.
Out of curiosity, do you easily have the data for how many months of the year crops are growing in each garden?
You commented once that there was a year of squash that was the best you've ever had, and it was the year after a massive fertility bomb in the simple garden. That was a huge mix of composting material. It probably brought in something deficient in your local compost, since you are mainly composting what you grow, or comes back from what you send out into the community. Geoff Lawton said something similar about his olive oil crop. Award winning, but highly diverse compost. And just realized your municipal compost may not be that diverse.
If you simply want to sequester carbon, biochar might be the way to go. Since the carbon in biochar is in the form of chemically stable charcoal, it shouldn't need inputs like nitrogen, phosphorus, and sulfur to stay in place like carbon that is actively being utilized by soil organisms.
It's interesting to see that cover crops doesn't improve the soil as we can expect it to do. In France there's a agronomist name Conrad Shrebber, who's study the matter. He and his team came to the conclusion that if you kill the cover before full maturity, it take more that it give.
Would it be a good idea to take ten soil scoops from around one garden – mix it and shake the soil and then take a sample from that aggragate to get a clearer representation of the overall chemistry of the top soil in that garden? It might smooth out the anomalies and outliers that you might get from testing just one scoop? – – – Also – it would be really good to be clear or even do a video on what "soil" is made up of. You/we commonly use the term "organic matter"- but its not obvious that this is as opposed to "inorganic matter". It's not obvious that soil is generally made up of rock particles (not ex-vegetable matter). When we get clear with the idea that soil is mostly mineral – it sets a context for the carbon sequestration question, the importance of preserving global top soils and how long nature takes to "make" an inch of organic top soil. — I constantly forget that soil is generally mineral – it looks brown and crumbly and like it's made of dead plants.
😊👌
On your soil test, what is the “desired value” and why is it different for each plot? Also, what is the reason for a lower ph in the no dig?
A very interesting video. Thanks Bruce.
It looks like the Simple garden’s soil is the poorest. I have , for the last six years been trying to improve the soil on my allotment in north east Scotland. Basically, it’s dirty sand . I produce about three cubic meters of compost each year and supplement this with chicken poop pellets.
Would liquid feeds such as nettle or comfrey teas deal with any deficiencies?
All the best
Generally in the winter time where there is lots of brown material I usually collect it and use it to add to my compost as well as shredd it to make a quick carbine release mulch, that’s what I’d recommend if you are able to get the resources
Wouldn't it be better to pulverize the charcoal and mix it with the compost? That what I always thought biochar was. ¯_(ツ)_/¯
Interesting as always, perhaps a few samples from around each plot and mix them to get a good average for each plot, assume you most likely did this?
I am also interested if there is a delay in how long the organic matter takes to show up in the tests, I'd imagine there could be some delay to see results similar to when you lime a croft
All of your videos are so well thought out and it is evident from the comments that I am not the only viewer who appreciates the level of detail and work you obviously put into these videos and your gardens. A big thank you from Australia for your excellent videos.
영상잘보고 갑니다.
편안한밤 주말되십시요. 😊
Always love seeing your videos pop up in my feed. They continue to be at a whole other level than most gardening/farming channels in terms of experimentation, analysis, depth and conceptual breadth.
Could you maybe grow some type of sulfur bioaccumulator?
You spend a lot of effort on the macros, NPK. It is very important of course because that is the foundation of every fkn thing. I wonder how much you have considered trace elements and their role in prolific growth. Iron, Moly, Magnesium, Copper, Boron are all very important. We do make a very lightweight mix of these things and foliar spray them periodically. It is very helpful and the results are obvious. Actually, the results of foliar sprays of seaweed and fish emulsions are pretty obvious too. I'd love to see you go down that rabbit hole.
Do you know if there are bacteria that convert insoluble sulfur in the soil to available sulfur? I think trying to aim for good soil health without inputs is the way forward. Especially on a larger scale.
Great thought provoking video as always…. just wondering if you use animal manures as inputs? I have watched most of your videos and I don’t remember seeing any although that could be way off.
You make biochar right? I can't remember. If not it might be worth considering.
3:40 Never mind. It's too early for me lol
Great video! I love your style, input and honesty! Your videos are packed full of information. Some I didn't even realize I needed to know!
The info good but his voice!
You've got me really curious about sulphur now too! I wonder is it a fairly specific to your context/ calcerous soil or a more common problem.
I've just been doing some soil sampling and sent off for tests for the farm where I work. Will be interesting to see the results. There the main soil building is through green manure so I'm curious if we're building or degrading soil organic matter.
In living soil handbook Jesse Frost suggests taking 10in cores and discarding the top and bottom 2in, to be effectively sampling the risosphere. Were lucky to have a proper soil probe that we must have been given at some point but it did feel a bit pointless disgarding the top 2in in areas where the ground had been recently ploughed.
After your last video I did a bit of a check of my books re sulphur and thought it was interesting know and grow vegetables mentions it as an amendment in relation to reducing pH… "In most situations the natural trend is for soil to become more acid so liming is normally required. A few soils may be desirable to make more acid, incorporation of acid peat can assist with this process (not recommended on sustainability grounds). Sulphur and Ferrous sulphate are also used with success on some soils"
Cheers as always, 🙂 Ben
Some suggestions for future testing:
-Collect multiple sample points from each bed so you can compute a average treatment effect accounting for random errors
-Standardize and document your specific procedure for collecting samples
-Consider adjusting the results for how much organic material you added to the bed (otherwise it's trivial that the beds you added more compost to will have more organic matter in them, so you don't learn much about your actual treatment other than that)
-For bonus points you can compute actual t-tests and linear models/ANOVA using the data you collected, this will let you determine whether your results are statistically significant
Hi Ben, Thank's for sharing your experienced. Banana peels has a lot of phosphorus; leave them in some water…
I love how this channel is driven by science and not a 'used-car salesperson' personality
Best gardening channel on youtube. So detailed and well made videos! Keep up the good work please. Always wanted to check how is Dowding method doing on paper. Thank yu very much!
my favorite time of the year! so excited to see you videos again. I wish you a wonderful year
for the Carbon to stay in the ground, life needs to stop. Carbon concentration is always in flux, as is all other nutrients. The act of removing the harvest from the plot is itself a big factor in reducing the carbon concentration of the soil. Which we as animals release in the form of methane back into the air, continuing the cycle.
as interesting as this study is, I don't personally think it plays a large impact in the local garden. maybe I'm wrong? Still, very fascinating.