Soil: is it just dirt?
courtesy of Bob McMahon
Our blog this week is provided courtesy of Bob McMahon. Bob attended the Agricultural College in Truro, and managed his family farm after graduation before going on to own his own shop (AnnVal Frozen Foods – a combination of butcher shop, grocery store, and freezer storage rental) and eventually teach meat cutting at Kings Tech (now called NSCC Annapolis Valley Campus). Bob hails from a family with multiple generations of dietitians: his mother was a dietitian, and his daughter and granddaughter are both currently practicing. Bob now resides in Waterville, Nova Scotia, with his wife Connie, and spends much of his time gardening and writing.
Good soil is alive with the sound of…music? earth worms? bacteria? fungi? amoeba?
Seriously - healthy, well-prepared and balanced soil is alive. In fact a spoonful of soil may contain over five thousand species of bacteria plus other microorganisms. The best soil is composed of approximately 44% common dirt (minerals), 25% water, 25% air, 5% organic humus, and 1% microorganisms. Microorganisms are instrumental in altering some plant food to a state in which the plant can use it. An example is commercial nitrogen, which must be refined to nitrogen sulfate (known as nitrogen ‘fixing’) before it is any benefit to the plant.
Most plants require a slightly acidic soil (pH 5.5 to 6), while others such as rhododendron thrive in a more acidic environment. Most gardeners do not have the facilities to test their soil but a container may be requested from the Dept. of Agriculture, in which to submit a sample for testing. When you’re buying plants make sure to ask what sort of soil is best for them.
So why does soil make such a difference? Many years ago when I was but a tadpole, my father had a four-acre orchard of apple trees. There were all the varieties of the time: Ben Davis, Gaino, Fallwater, Bleneim, Northern Spy, etc. The trees were approximately twenty-five years old, stunted and producing little fruit. Between the rows of trees was almost barren land with a carpet of devils paint brush, plantain, and other useless weeds. Every year my father put more fertilizer around the trees - but it was wasted and leached into the groundwater. The soil was dead, sour, and breathless. One day, he sent soil samples to the Dept. of Agriculture for testing. The report came back recommending four tons of lime be added per acre, one ton per acre each year, for four years. Dad was in a hurry so he ordered a boxcar load of lime and we put it all on in one year. Then we added humus in the form of rotted sawdust and plowed between the trees, and were able to harvest excellent clover hay from between the trees. I am sure that it was not just my dad, my brothers, and I singing then, but the soil as well!
There is a saying that refers to the poor practices involved in the preparation and stewardship of soil. It is called “the cycle of death”. It occurs when a gardener, seeing that their plants are not responding as anticipated, adds more commercial fertilizer. The salts etc. in the fertilizer kill the much-needed microorganisms, and the soil balance is corrupted. The plants wilt and fade, so more nitrogen is added to “green up” the crop. At the same time, the extra travel and tillage required in adding the fertilizer tends to further compact the already weakened and dying soil, and it can now be truly labeled “dirt”.
There are ways to physically assess the condition of garden soil. Walk in it after a moderate rain. If you sink in it over an inch, it has too much clay mix. Add humus or compost. If you do not sink in it a half inch, it is too sandy or compacted. Till in compost. Also, if you take a handful and squeeze it between your hands, good soil will tend to hold its form for a short time after the pressure is removed.
The Halifax Garden Network http://halifaxgardennetwork.com/, which sponsors Community Gardens throughout the
Metro area, may be an excellent source of gardening information if you’re looking for more help with your soil.