Balancing Soil Minerals here at the Sustainable Smallholding has been occupying my thinking for a few weeks now. It started a while back after reading ‘Advancing Biological Farming’ by Gary Zimmer, but my thinking took a huge leap forward after reading ‘The Intelligent Gardener’ by Steve Solomon, and settled after reading ‘The Ideal Soil’ by Michael Astera and ‘Soil Fertility’ and Animal Health by Albrecht. Until this reading bout had started I was reasonably sure that my fertility building regime was good, but I realised that I was missing out on what may be a vital part of any soil building strategy. So what have I learnt about Balancing Soil Minerals, and more importantly what have I done about it? Well read on and find out 🙂
Balancing Soil Minerals: Why Bother?
I would guess that most people reading this will believe that adding sufficient organic matter to their soils is all of the fertility building that they need to do. This attitude has been promoted by Organic Gardening advocates for more than 50 years. So why worry about minerals? I think that I’ll try and answer that with a question for YOU. If your soil is missing essential minerals, where will those minerals come from? If they’re not in the soil itself, your own composting materials will be short of them, so the compost that you make will also be short. If your organic matter is coming in from outside how do you know if it conains the minerals that you need? If they are there, how would you know?
Reading Albrecht really opened my eyes to the consequence of mineral shortages. If I am what I eat, and I am eating food that I produce myself, if my soil is short of any essential mineral, then I will be too. Whilst Soil Fertility and Animal Health is ostensibly about animal health problems resulting from mineral deficiencies, the same will apply to us. So balancing soil minerals is also helping to improve the nutritional quality of my own food, and consequently my health. That’s a good enough reason for me to want to find out more.
There is no real way of knowing what is in your soil without a proper test. So balancing soil minerals depends on the results of a soil test. Using indicator plants, and a bit of educated guesswork, my best guess was that my soil was acidic, low on Calcium, and possibly Phosphorous, but high in Magnesium. (Magnesium binds clays more tightly, and my soil is very heavy). I started to investigate the best sources of these minerals before sending off for a professional soil test. I’m really glad that I waited before spending my cash. My soil test results are below.
My Soil Test Results
This is the report that I got back from the Laboratory in PDF format in case any of you want to play around with it yourself..
The JPG looks like this.
There are two test results on the form. The left hand one is from my first vegetable growing area. It has been growing food for me for 10 years now. The beds are dug occasionally, I suspect about four or five times since I began, including the initial weeding. The second column is for an area that is going to be the site for a polytunnel. It has never been cultivated, but has been dug and weeded once, last year. Before then it was where I dumped most of my weeds. Any that regrew were scythed. So it has had raw organic materials added, whereas the vegetable area has been maintained using compost.
Soil Test Inititial Thoughts and Comparisons.
I’ll be doing a full analysis of the results in another post, but there are a few interesting things that can be pointed out and aired here.
The results are quite similar, which I was pleased with. It means that my soil management, and soil fertility building are doing OK. If there was a significant reduction in minerals in the vegetable test, compared with the polytunel site, I would have been concerned. In fact many of the minerals that I will be looking at are present at a higher level in the vegetable area than in the polytunnel site. This suggests to me that we are importing fertility from outside. Calcium and Phosphorous are potentially coming in as poultry food, bedding, or manure, including the calcium added to their feed for keeping the egg shells hard. As this all ends up in my compost, it is a potential source of some of those surplus minerals. The higher level of calcium in the polytunnel test was surprising, but may be down to the occasional use of that area for burning wood and other rubbish, including my recent experiments.
The more observant amongst you may have noticed the higher level of organic matter in the polytunnel site. This might lead some to suggest that not digging has built up higher levels of organic matter there than in the area that has been dug. I would counter that with the fact that the target level for organic matter is 7% in a cool climate, which is what I’ve got. No need for any more than that.
Soil Mineral Levels
If you look at my earlier guesses about my soil mineral content, you’ll see that I was wrong with my assumptions. Soil Ph was neutral or as close as it could be. Calcium levels were high, as were Potassium and Phosphorous. Magnesium was low, not high. I am also low on Sulphur and Manganese. Without the accuracy of a soil test, my attempts at balancing soil minerals would have created a bigger imbalance, as well as wasting money. Now I have an accurate base line to work from, and a way to evaluate the efficiency of my attempts to build soil fertility, including balancing soil minerals.
I will go through my analysis, and calculations in another post, including how I intend to proceed with my soil mineral balancing. In the meantime, there is plenty of information on the soil mineral.com website. You can also read much of Albrecht’s work, including Soil Fertility and Animal Health, for free from the Soil and Health Library. I can also recommend the Michael Astera essay, but warn you that both could challenge the way you look at Mulch gardening for ever.