Just as he demystified the soil food web in his ground-breaking book Teaming with Microbes, in this new work Jeff Lowenfels explains the basics of plant nutrition from an organic gardener's perspective. Where Teaming with Microbes used adeptly used microbiology; Teaming with Nutrients employs cellular biology.
Most gardeners realize that plants need to be fed but know little or nothing about the nature of the nutrients involved or how they get into plants. Teaming with Nutrients explains how nutrients move into plants and what both macro-nutrients and micro-nutrients do once inside. It shows organic gardeners how to provide these essentials. To fully understand how plants eat, Lowenfels uses his ability to make science accessible with lessons in the biology, chemistry, and botany all gardeners need to understand how nutrients get to the plant and what they do once they're inside the plant.
Teaming with Nutrients will open your eyes to the importance of understanding the role of nutrients in healthy, productive organic gardens and it will show you how these nutrients do their jobs. In short, it will make you a better informed, more successful and more environmentally responsible gardener.
Where to get it?
I read this book as a companion volume, written by one of the same authors, to Teaming with Microbes, which I've reviewed elsewhere on the site: http://www.permies.com/t/51857/books/Teaming-Microbes-Jeff-Lowenfels-Wayne#464319. Teaming with Nutrients discusses the details of plant nutrition, which will be influence by the microbiota in the soil, discussed in the previous volume. This book introduces you to the interfaces between biology, chemistry and, to a point, geology and physics. It's a systems book, and in many ways just as interesting as the first one. It's a much heavier read, however, and an understanding of it is probably much less important.
The book begins with a surprisingly detailed chapter on the plant cell. I recently read another book on Botany for Gardeners http://www.permies.com/t/54891/books/Botany-Gardeners-Brian-Capon#455142, and this book actually goes into more detail. Some of this is quite technical but is backed up by clear illustrations. It probably pays to understand what is going on at a cellular level, but maybe not in this much detail: Lowenfels is not as good at describing the processes involved to the beginner as is Dr Capon. The introduction to basic chemistry is at no higher a level than I'd expect a 16-year-old to know, and is relatively straightforward. You probably do need to know this if you are going to try to understand how plants use nutrients.
Chapter 3 on Botany or, more accurately, plant physiology, is also highly detailed. This is also useful to know if you want to understand how plants use nutrients, and covers at least some details not covered by Capon, but I kept wishing Lowenfels shares Capon's knack for explaining it. The material is clear, but I found myself having to go back and reread much of it in order for it to make sense. It does make sense, but it's not something you want to read without lots of coffee or plenty of sleep – in spite of the fact that the material is already mostly familiar. There is brief mention, in some cases, of essential nutrients used by certain types of plant cell. Chemical signalling is used in order to change the relative concentrations of plant exudates in order to manage the microbiota around the roots in order to change the concentrations at which various nutrients become available: plants, in effect, farm microbes. Part of our job (see the previous volume) is ensuring the microbes and the nutrients are there in the first place. The plants will do the rest.
By the time you get to the end of this chapter you should have a grasp of how plants move nutrients around, from water to minerals, from a cellular level upwards, and to a point why they need them.
Chapter 4 moves on to the nutrients themselves: a plant needs, in varying quantities, about 17 different chemical elements. In terms of mass, about 96% of this comes from carbon dioxide and water. Depending on the degree of control you have over your growing conditions, you may need to think about all of them (a greenhouse can deplete carbon dioxide pretty quickly). There is also a case for ensuring a source of others including cobalt, which is not used by plants, but is used by bacteria for synthesis of essential vitamins in animals, as well as iodine (used for hormone regulation), selenium (used in animal metabolic processes) and several others; animal cells also require sodium, but this is toxic to plants even in quite low concentrations (less so in C4 plants, which can use it). These are not essential for plant growth, but humans (and most other animals) do need to ingest these substances, and many plants can and will use them.
Many vital aspects of the structure of a plant, both at a cellular and a macro level, is involved in the transport of the most valuable substance in the universe, dihydrogen monoxide. Water is also the medium in which nutrients move, which is the subject of the next chapter.
This is where all the chemistry learned in the first chapter becomes useful, explaining why the fact a particular element is present in the soil does not necessarily mean a plant can use it, which is one place the soil microbiota is essential to healthy plants. Even many soils damaged by the additions of herbicides, fungicides and pesticides may not lack nutrients as such, but lack the availability of those nutrients to the plant. Ion exchange capacity also counts, but this is also related to a healthy soil microbiota. You simple can't think about these things in isolation, as conventional farming does – or if you do, it will have long-term consequences, at least to the local ecosystem. The plant isn't bothered whether you add nutrients as compost or as artificial fertilisers. Everything else is. You are then given a lot of detail, probably first-year degree-level detail, about how the plant shifts water and other nutrients around. This is all much more complicated than the companion volume, and it must be said that most gardeners, indeed most Permaculturalists, don't need to know most of it. I do think there are things in here that it is very worthwhile to know, but sometimes it felt like there was too much data.
Having covered all that, it's time for some molecular biology. It's entirely logical, building up from simple sugars to more complex carbohydrates, to amino acids to proteins and so on.
From here it gets simpler; now you understand how plants manage nutrients, it's a case of applying the knowledge. The chapter on soil testing, indeed, many not teach you much you didn't already know, assuming you've been paying attention. Factors that affect nutrient availability may also be known to you: but while microbes that provide nitrogen are at their most active between 24C and 35C (75F and 95F for anyone in Liberia, Myanmar or the US*), photosynthesis becomes quickly less efficient much above 30C. Then you can learn what and when to feed them.
This is when the book, and indeed we, run into trouble. Now, I agree completely, for reasons that author discusses, that we need to be weaning ourselves off industrial fertilisers. That's not at issue. It's also worth pointing out that this book is aimed at gardeners, and at the level of a suburban back garden things like bat guano may make some sense. It's not going to work when you have a hectare of forest garden to worry about, never mind several. He gives a long list of possible soil amendments, the vast majority of which are byproducts of industrial monocultures (not sustainable, or most of us wouldn't be here), the meat industry (not sustainable for the above reasons and several others) and fish byproducts (about which don't even get me started, given the worsening rate of ecosystem collapse in the world's oceans). Even things like alfalfa meal and cottonseed meal are in effect simply robbing one bit of land to add nutrients to yours. This just can't work in the long term. I'm not saying we shouldn't use these things, but there are obvious sustainability questions.
He makes the point (entirely valid in the US and several other countries where government regulation of corporations has collapsed) that many of these additions are also likely to come from GM crops, and are unlikely to be considered “organic”. The book has already made the point that plants can only take up nutrients in ionic form, so the chances of proteins from GM crops finding their way into yours, at least by this route are, by definition, nil. Actually, I have many, many issues with GM crops, and flat out oppose their commercialisation, but the author's evident ignorance on this subject (about how you might ingest Bacillus thuringiensis**, for example) helps nobody.
In many ways there are few simple answers to this problem. The right rock dusts will provide many minerals but some, such as rock phosphate, are in increasingly short supply. I'm a big fan of using seaweed (although this also has sustainability issues), and of returning both liquid and solid (which the author doesn't mention) human wastes to soils, thus closing nutrient loops. Accelerated rock weathering can also, for some rocks, sequester carbon, but this may also make other essential minerals inert, so caution and a grasp of chemistry is needed (in due course I may write a post about this, as much for my own use as anything else, because I don't understand it: it may be a means of sequestering carbon while making nutrients available to plants, but it certainly depends on the rock).
This is not a bad book, but I'm struggling to see its direct utility. The first part is probably too detailed for most, while the second mostly contains information available elsewhere. If you want to geek out on plant cell biology, this is an excellent introduction. It is strong on the reasons why it's important not only to test your soil and amend accordingly, and most of us still fail to do this. It's worth a read, but maybe not at the top of the pile.
* I like the way that, in spite of this book being a US publication, the author gives measurements in metric units. In many cases this is simply because giving numbers in fractions of an inch rather than microns makes no sense; elsewhere he makes the point of giving both metric and archaic units.
** There is, I suppose, a chance that Bt toxin residues might poison your soil microbiota. The GM crops themselves do not produce Bacillus thuringiensis itself, but the toxin that Bacillus thuringiensis produces. Don't get me wrong: this is problematic, and so is the commercialisation of the crop, but you don't have to worry about the toxin getting into your food supply as a result of using crop residues from plants modified in this way. The science in this book is otherwise accurate, as far as I can see but, if we are going to oppose GM, it needs to be done on the basis of sound science (seriously: pleiotropy!) and awareness of the socio-economic impact of the stuff, not ascientific fearmongering, which just allows the corporate interests to discredit us.