Wednesday, November 13, 2013

Soil magic

Soil magic 

Nerd Alarm: this for all the garden lovers (who wish they hadn’t drop out of biology in 11thgrade)

„Of course you have terrible soil problems in your country. What do you expect when you call it dirt” 

My number one take-away from my agricultural project: It’s all in the soil. 
Take away number two: Forget about composting else-where, pile it all on the bed – and call it mulching. Most of the following sophisticated-sounding data comes from ‘GAIA’S Garden by Toby Hemenway. 

Okay, so I was trying to understand what is going on in the soil, and how I can help my plants to become big and strong ... and bear delicious veggies for me. so here the amateurish attempt to summarize what scientist can explain much more detailed, but way too complicated for me to understand... hopefully it still makes sense: 

So... let’s start in the beginning. Soil is pretty much everything – it’s like our supermarkets, kitchens, roads and hospitals – it provides the plants everything it needs. Its magical and miraculous, but likes to be taken care of as well, because in fact it is full of life. And like all living beings, they want to be loved : )
I didn’t really think I would need biology in my later life this much, so when they talk about all the organisms I tend to get a bit lost. But I do understand numbers… so here one concerning the life in one teaspoon of soil: one billion bacteria, one million fungi and ten thousand of amoebae. I always has a hard time picturing anything smaller than a cat, but clearly there is a lot going on in this seemingly lifeless spoon full of soil (btw there is also clay, sand, water, air and humus on the spoon!). 

Soil is also the home for worms, millipedes and mites (among others) who eat stuff you put on top of the garden bed, let’s say dried leafs.  So they eat this ‘organic matter’ and of course have to use the bathroom – their poop being super food for plants, easy to take in via roots, also because those little worms loosen the soil when building their underground mansions. Millipedes, bugs, beetles, snail, spiders, ants, ... all help as well.

All to help and grow delicious food for us! Pretty magical stuff, Mother nature. 

For the ones that realize that there is a bit more to this…
So some parts of these leafs can’t be ‘eaten’ by the plant just yet. So other organisms, such as fungi, break down the pieces further. I guess it’s like mom cutting the Steak into pieces for the little ones, after dad cooked it already (or in the worm example: pooped it out). Maybe not the best metaphor, but it is just to illustrate that the life in soil is like a big family, working together, breaking down and preparing food for the plants. The x-mas dinner being HUMUS. Humus is the end of a process (that is poorly understood) in which microbes and other ‘forces’ convert the ‘hard-core’ leaf compounds – maybe like your favorite aunt that prepares the most delicious dessert, even the most pickiest eater cannot resist. I am thinking warm apple crumble with ice cream – only out of hard-core leaf compounds. The dirty dishes  are the humus – only that they are biodegradable eventually and has more to offer than attracting cockroaches when it sits around. Humus can be described as ‘the end of the road’ for organic matter, but it is also very good at holding moisture and at the same time fluffy enough to let roots and soil organisms easily dig tunnels in search for food (which airs out the soil further). On top of it humus is really awesome at bonding with other nutrients. 

This part is for all the people that also regret dropping-out of chemistry class…
So humus involves a lot of oxygen atoms, which are negatively charged. And as opposites attract, it catches some other important food for the soil and animals in it, which are: potassium, calcium, magnesium, ammonium, copper, zinc, manganese…. So it is kind of like the dirty dishes  attracting cockroaches, and other animals after all. Assuming you like cockroach stew : )  
Because the nutrients on the humus molecule are actually washed into the soil, creating like a really healthy soup, which can be drunken by the plants, until they are full (to avoid depleting the humus) 
So just to complete the list: microbes also excrete/poop-out  food for plant, and together with fungi they even secrete antibiotics that protect the plants from disease. Again, my conclusion: pretty magical stuff, mother nature – and: it’s all in the soil. 

If I you are still with me after all this detail, you must like it to some degree, so no stopping us now… to dived into this whole Nitrogen - Carbon thing, people throw at me, every time I encounter a fellow gardener. 

So, here it goes… our leaf, like most living things in fact, is primarily made out of carbon. When the little animals eat the leaf some of the carbon is digested and ‘reused’ so to say by them (to form a membrane or an eye ball :) the rest is released as gas (carbon dioxide aka CO2 – our breath contains CO2 for the same reason btw). There are other elements in the leaf, such as nitrogen, calcium, phosphorus – usually also digested and staying earth bound. With the CO2 escaping into thin air, obviously its ratio to the other elements is decreasing, right? Specifically interesting for garden enthusiast is the ratio toward Nitrogen, and they love to mention of C:N or Carbon to Nitrogen ratio. 

Carbon is a bid of an Houdini, only that a piece of him goes to everybody in the audience (as you can see, I am continuing my row of bad metaphors)  So by the time the microbes (who are kind of last in line at the buffet) are finished with the leaf, most of the carbon is gone. All that is left is inorganic/non-carbon matter such as phosphate, nitrate, sulfate, and stuff they like to put in bags and sell them to us as fertilizer (only that plants can absorb just 10% of the applied fertilizer and rarely more than 50% of those mixtures, leaving the ‘rest’ to be flushes in streams, lakes and ocean). So we could get it for free – no shipping and handling and already mixed in with the soil – if we let nature run the show. 

Keeping the carbon coming seems like an important part of feeding those little one, as organisms need about twenty parts carbon for every one part of nitrogen (similar to my chocolate intake compared to all other foods). The other three letters that are used in gardening are: NPK – nitrogen we already know, that there is phosphors and potassium (why they didn’t call it NPP only god knows). 

Anyhow, how to we get all this letters to our soil: 

Add Organic Matter! Apparently you can do this via compost, mulching or cover crops. Since I am on the lazy side, I am all for mulching. It is like composting right on the garden bed, only that you also kill weeds, protect the soil from harsh sun and heat, or rain, keep the moisture in and provides food at the same time! 
Clearly Good stuff. Apparently there are some sophisticated methods on how you can sheet mulch multiply layers. 

Without sheets I just use this stuff: dried leaves, dried leaves crumbled up, wood chips (cut ourselves), hay, hay with rabbit poop, and chicken poop. It’s like tucking you kid in at night – a cold night I guess, trying to cover everything with a heavy blanket.    
 Other material you can use: newspapers, lime, rock phosphate, bone meal, straw, yard waste, seaweed, sawdust, pine needles, grain hulls… and much more. 
The kitchen waste was a bit of a disappointment. Apparently its better to build a worm mansion separately, were the little fellars can take of all Your garbage....

Enough science for today. Take away: Nature is magical, soil your sole concern when gardening : )

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