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IT'S TIME FOR SHARING (Continued) for their sustenance is excreted as require oxygen (anaerobic) causing putrefaction or the of organic matter decomposition. Whereas organic
nutrients to be consumed by plant rotting smell common to water logged, oxygen deprived matter must be replenished either naturally, such as leaf
roots. The protozoa and nematodes soil. How many times have we heard that plant roots need litter in the forest or from soil amendment by us, humus
consume the bacteria & fungi, and oxygen? It is true that roots need atmospheric oxygen but is thought to remain in the soil indefinitely due to its
the arthropods feast on the protozoa it is also true bacteria need oxygen to produce organic insolubility. Fungi grow into long thin threads (mycelia)
and nematodes. A healthy soil food matter decay releasing nutrients needed by the plant reaching well into surrounding soils of living plants. A
web cannot exist without plants and roots. Plants also obtain oxygen from water. symbiotic relationship beneficial to both the plants
microbes. Of course, this understates and the fungi can result; these fungi are known as
Three types of soil bacteria perform roles in the
the incredible complexity of the mycorrhizae. The mycelia become entwined with
development of healthy soils; a fourth works against the
system but is how it works in the plant root hairs and the soil. These mycelial growths
process.
simplest explanation. can either form a sheath around the root hairs or
Nitrification. This is the process of transforming become concentrated at the root tip. Mycorrhizae draw
Plants are called autotrophs because ammonia nitrogen, not usable by plants, to the useful
they make their own energy; they are form of nitrates which plants convert back to proteins. carbohydrates from the root and provide nutrients to
also called producers because they the plant. Mycorrhizae have evolved to the extent that
produce energy available for other Nitrogen fixation. This process converts atmospheric some are mated to a specific plant genus. Fungi often
organisms to eat. nitrogen into the ammonia form making it available for produce above ground fruiting bodies, (collectively called
nitrification. Some nitrogen fixing bacteria live in close mushrooms) that animals feed on and can subsequently
Heterotrophs are consumers that proximity to legumes and fix nitrogen into organic bearing disseminate spores. And you thought deer in the nursery
cannot make their own food. In order nodules. or landscape were a bad thing.
to obtain energy they eat plants or Friable Soil Wanted!
The chart above generally shows all these processes in action. Many will remember this from school as other heterotrophs. Actinobacteria. These good fellows are responsible Friable soil refers to the aggregation of sand, silt, and
The Nitrogen Cycle. Source: Wikipedia Arthropods for converting organic matter into humus; more about
humus later. clay particles into larger, visible aggregates. Sand sized
By definition an arthropod is an Denitrification. This is not a good thing. These bacteria, particles are visible to the eye but silt and clay particles
animal with segmented bodies, mostly anaerobic, convert stabilized organic nitrogen are microscopic. The soil textural chart shows the
jointed appendages and a hard back into the gaseous form releasing back to the desirable percent of each particle size to form a good
outer skeleton or exoskeleton. atmosphere. This occurs when soils are deprived of soil of the clay loam to medium loam characteristics; this
Examples living in the soil food web oxygen and the putrefaction process takes over. favorable ratio does not necessarily indicate soil quality.
are hundreds of different insects Friable soil is easily crumbled and that is the easiest
and spiders. They impact the soil Fungi way to begin the analytical process of determining soil
food web by eating nematodes Soil fungi are usually yeasts and moulds. Fungi cannot quality in the field. The larger, aggregated particles are
and protozoa. While rooting around produce their own food and rely on a chemical source of the essence of good soil. They form as a result of all the
in the soil for food they aerate it, energy rather than sunlight as well as organic substrates activity in the soil food web.
incorporate organic matter and as a source of carbon for growth. Parasitic fungi such as Bacteria will simply ‘wash’ away if they do not bind
mix the profile. Ants are particularly pythium and rhizoctonia are damaging to plants while to something. To affect this ability to bind to individual
adept at this function. other fungi are antagonistic toward damaging fungi and soil particles they exude a slime that acts as glue. Fungi
have beneficial plant relationships. Saprotrophic fungi
Beyond arthropods but equally produce hyphae as seen above and these structures stick
which live on dead or decaying organic matter are
important are worms, slugs, insect to the soil particles. Working together, bacteria and
responsible for humus creation. Humus is the end product
larvae, and snails who also digest fungi ‘glue’ the soil particle types into aggregates.
and mix organic matter.
Mycelial cord made up of a collection of hyphae; a key part in the process of saphrotrophic nutrition, it Bacteria Plants are called autotrophs because they make their
is used for the intake of organic matter through its cell wall. The network of hyphae is referred to as a Soil bacteria are the engines of
mycelium, which is fundamental to fungal nutrition. Source: Wikipedia
organic matter decay. Without them own energy; they are also called producers because they
organic matter would just collect
and provide little benefit. There are produce energy available for other organisms to eat.
good bacteria requiring oxygen to
survive and bad bacteria that do not
18 SPRING 2024• Free State News Membership Matters • SPRING 2024 19
