Permaculture Design Course Day 4

The Sunday of the second weekend was mostly spent considering soil.

Firstly it should be known that approximately 50% of a good healthy soil is air and water. Now how much of either is dependant on how recently it has rained and how much and how well drained/draining the soil is. The other 50% is mostly mineral with a degree of organic matter again this is a bit variable again; obviousley Pete has a much higher organic material content, is almost solely organic material.

Of the mineral content there are 4 possible components: Sand, Silt Clay and Chalk. I can say that I know nothing about chalk we competly skipped that on the basis that there was nobody there who needed to deal with chalk.

Sand consists of the largest particles (between 0.05mm to 2mm). Silt particles are the next largest (between 0.05 and 0.002). Clay is the smallest (less than 0.002mm).

So your soil can consist of any one of these (or chalk) or it can be a loam which is a mix of the three.

We went out and dug some holes to analyse the soil by spit balling (spitting on the sample rolling it into a ball and seeing how long it sticks together). We also took some samples in jars to take back to the classroom.

In the classroom we learnt how to analise a soil sample more thoroughly. We had our jars about a fifth full with the soil sample and filled to the top with water. We then shook the samples vigourously for about 5 minutes, this broke the soil down seperating all the particles and leaving them in a suspension in the water. You then leave it for a couple of weeks and see how it setles. The sand will settle first, then the silt, the clay and then the organic matter - and who knows about the chalk- in distinct layers.

We had a little play with some builders sand and some potters clay and soil conditioner (basically tiny twigs and brittle organic material) mixing clay and sand makes a mix more suitable for plant life, but any organic material instantly enriches the clay or the sand.

This led us on to consider composting and more specifically worm compost. Worm casts (poo/compost) are incredibly fertile and amazingly are5 times richer in available nitrogen, have 7 times more phosphates and 11 times more potash than the upper 6 inches of topsoil.

We looked at a good rat proof design for a worm composter made out of old tyres... I'll see if I can do a drawing to post as a pdf or something as it's quite hard to explain verbally.

So the last thing we talked about on the soil front was the microbes! Microbes are very important to healthy soil and most of the bacteria is in the top 2cm of soil. There are 1.5 billion bacteria in this top 2cm of soil! This is one reason that permaculturists consider ploughing such a bad idea! And obviousley there is the negative influence of chemical fertilizers on these bacteria to be considered!

So in the middle of that we had a quick look at Zone 1! This is the zone nearest to Zone 0 which is your centre of human activity or house! A number of elements should be kept in this zone which should be visited on a daily basis. You need your compost/wormery, your woodstore, clothes drying, animal houses (you need to let the chickens out of the house every day but their run can be in zone 2), herb garden, water but, recycling, indoor/outdoor space (greenhouse/conservatory) for exotics and seedlings and your salads.

So there we go! I'm very much looking forward to the next weekend towards the end of this month.