Page 33 - Simply Veg Issue 1 2016

Straw mulch keeping in moisture and warmth
bacteria and other very small creatures and they can be eaten by even larger creatures like frogs, toads and other mammals. The cycling of these soil organisms helps to cycle the good that is in the soil which can then become available to the plant. The soil food web is the basis of a healthy, fertile and therefore productive soil.
So looking at what these organisms do
in more detail will show how important they are to the soil and to the human race, well at least us gardeners!
Raised beds means no water logging as you have the drainage
Bacteria - are single celled micro- organisms that inhabit a wide range of habitats from humans, other animals, and plants and in the soil among many other habitats. There are varying estimates of how many bacteria are in
a tea spoon of soil
but they range from
100 million to 1 billion
( I am not sure who
counted them!). The
soil inhabiting bacteria
can be grouped into
decomposers, mutualists, pathogens and chemoautotrophs. The main ones we will be aware of are the decomposers as it is these that produce the compost in the compost heaps and the pathogens which are the ones that cause disease problems in plants.
Bacteria that improve soil quality feed on
and decompose organic matter, helping to keep nutrients in the rootzone, enhance the soil structure, compete with disease causing soil organisms and (there is a lot of research looking at this as a method of disease control in the future - Ed) lter and degrade pollutants in the soil.
Fungi – are a diverse group of multi cellular organisms and the best known are the mushrooms, toadstools, moulds and yeasts; but there are many others that go unnoticed especially those living in the soil such as mychorrhiza. Most fungi grow long thin strands called hyphae which can be several metres long and push their way through the soil. Fungi can be grouped as decomposers, mutualists and pathogens; many diseases
but holds onto some water for the plants. Again there are fungi that help to control some diseases, these are called antagonistic fungi as they use the food that the disease needs but do not damage the plants. There are also fungi that attack pests and kill them, (Verticillium lecani which helps to control aphids, it does not live in the soil but is sprayed on to the plants, and more are likely to become available in the future).
Protozoa – these are microscopic single celled organisms that feed on bacteria, whilst doing this they release some nitrogen into the soil as the bacteria contains more than the protozoa can use. Protozoa also prevent some pathogens from attacking plants so assist in the growing of healthy plants. They provide food for some nematodes in the soil food web so are part of a healthy soil.
Nematodes – are small un-segmented round worms that live in a wide range of habitats including the guts of animals.
The soil inhabiting types consist of both bene cial and pests, an example of pest’s are the potato eelworms and the stem and bulb eelworm that attacks onions as well as many other plants. Most of the eelworms are bene cial, as many of you will know they are used to control pests such as slugs, vine weevil grubs, leatherjackets, chafer grubs and wireworm. Other bene cial eelworms feed on bacteria, fungi, and other eelworms including some of the pest types.
Arthropods – these are a large group of small creatures that includes the insects, spiders, mites, ants and beetles. Their
size varies from microscopic up to several centimetres in length and most live in the
top 75mm of the soil. Arthropods are a large part of the soil food web and improve the
soil structure by creating burrows in the soil, depositing excrement, controlling some pests and diseases and enhance decomposition
by shredding organic matter that makes it easier for the bacteria to breakdown. The shredders include millipedes and sowbugs other groups include the predators such as spiders, scorpions and centipedes; as well as the herbivores that eat plant material which includes the symphalids, root maggots and the springtails that feed on fungi and dead or dying plant material.
The Earth worms are of major importance in a healthy soil and I will cover these in the next issue of simply vegetables.
Earth worms are of major importance in a healthy soil
are caused by small fungal organisms some of which are
air borne but others which live in the soil or are soil borne. Fungi that improve soil quality decompose
complex carbon compounds, breakdown organic matter (this is how leaf mould is produced- Ed). Fungi help to retain some nutrients in the soil and assist in binding soil particles together to form aggregates / peds which help to form a good soil structure which is both open for drainage and aeration
Being able to reach the middle from either side means I don’t have to dig
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