Soil Samples

My last few assignments have been about soils and fertilisers. The materials accompanying the modules encourage students to take soil samples from their land and test them to see what nutrients are lacking.

I don't really have the equipment, time or inclination to take soil samples at the moment. (But if I change my mind in the future, I think I'll be using this online manual to work through the various tests.)

Fortunately the builders dug a large hole at the back of our house so I have been able to take a closer look at our soil structure in any event. (I know that proper soil samples should be taken away from buildings but this is the best of a bad job!)



For the last few weeks, I've studied the hole through the laundry window almost every time I've put a load of washing in. The soil structure hasn't changed over that time sadly.



I already knew that we had clay soil - prone to waterlogging and compaction when it rains heavily and then cracking in the hot weather. But I've learnt that the yellow-brown colour with red and orange mottles reveals that the soil has been affected by periodic waterlogging. At least it isn't prolonged waterlogging.

I also knew that we had very little topsoil (though I hadn't remembered that this layer is called "horizon A"). That's why we're going to be doing most of our growing in raised beds where we can add a rich layer of organic matter on top of the poorer soil.

I could have guessed that we would have poor soil structure too - you can see the large blocky peds which are the big cubes of earth which make up our soil and which make it difficult for roots to penetrate. That's another reason why we need to add that rich organic layer using compost which will consist of finer granules - crumb.

On the positive side, I've learnt that clay soils have inherent fertility levels which are relatively high and the nutrients in a clay soil are readily available to plants. That's something to be thankful for, at least!