Ivydene Gardens Soil:
Soil Formation - What is Soil Structure?
 

Soil Structure

This describes the way in which sand, silt and clay particles are bonded together in larger units called ‘aggregates’.

These are formed when the soil is subjected to shrinking and swelling, plant-root penetration or freezing. All these processes tend to break the soil into discrete units. Aggregates are said to be stable when they are able to resist pressures caused by processes such as compaction and sudden wetting. Rapid wetting is a process in breaking up unstable aggregates, because when dry aggregates are suddenly exposed to water, pores near the surface of the aggregate become filled with water, trapping air inside the aggregate; the resulting pressure can sometimes be enough to break the aggregate apart, and this is called ‘slaking’. Aggregates are divided into microaggregates (less than 250 millionths of a metre) and macroaggregates (greater than 250 millionths of a metre).

Before microaggregates can form, microscopic clay minerals need to be grouped together in small stacks called ‘domains’. When clays are bonded together in this way, they are termed ‘flocculated’.

The most important factor influencing flocculation is the presence of ions with more than 1 charge. When clay minerals are covered with singly charged ions they disperse and become deflocculated (i.e. they will absorb a great deal of water without it draining).

However, not all ions carry only 1 charge.

For example, calcium (Ca2+) in lime or chalk, Magnesium (Mg2+) and aluminium (Al3+) are 3 very common ions in soils. Ions with multiple charges allow clay minerals to bond together to form domains. Once clay minerals are stacked together to form domains, they can then bond with organic matter to form microaggregates.
Lime (Calcium), Magnesia (Magnesium) and Alumina (Aluminium) are 3 of the 11 chemicals with ions in the soil and are further detailed below followed by their affect on their lack or not; in Sandy, Calcareous and Clay soils.

The interaction between clay domains, organic matter, silt and sand particles diagram.

Once microaggregates have formed, they can then coalesce to form macroaggregates. In soils that have low concentrations of clay, macroaggregate stability is highly dependent on organic matter.

The type of organic matter associated with macroaggregates is slightly different from the persistent organic material found in microaggregates. Type one are those stabilising agents that are referred to as ‘temporary’. These consist of microbial and plant by-products, the most important of which are the ‘polysaccharide gums’ that are simply long chains of sugar molecules. Secondly, there are ‘transient’ stabilising agents, which include the fine plant roots and fungal hyphae.

Both stabilising compounds are vulnerable to microbial attack so need to be replenished continuously through inputs of fresh soil organic matter.

If microaggregates do not have a continuing supply of organic matter, then they will break up so that soil particles simply return to being sand, silt or clay.

Saxigraga oppositifolia

Bonding Family and Friends

"...even those for whom cooking is an oppressive chore or a source of self-doubting anxiety, achnowledge that a meal shared by friends and family is one of the bonding rituals without which the family, society even, can fall apart." by Antonia Till from "Loaves & Wishes".

The following information comes from pages 30-34 of the 844 in
"Beeton's New Book of Garden Management" by Samuel Orchart Beeton;
published in 1870 by Ward, Lock & Co., Limited. ASIN: B000WG5WKK.

Soils may be said to consist of a mechanical mixture of 4 substances -

• 1. Silica, silicious sand, or gravel,
• 2. Clay,
• 3. Lime and
• 4. Humus,

with many of the following 11 chemical substances , in varying proportions:-

Chemical

is contained in or made from

Benefit

Potash - is the common term for nutrient forms of the element potassium (K)

This substance is obtained by burning wood, small branches, or leaves, the ash being washed in water, and evaporated in an iron pot and calcined. Add a small quantity of water, decant the liquid, and evaporate to dryness, and pearl-ash is obtained, which is an impure form of potash in combination with carbonic acid, or crude carbonate of potash. When this is boiled with newly-slaked quicklime, it is deprived of carbonic acid, which enters into combination with the lime, and the carbonate of potash is thus converted into pure or caustic potash, which can be separated into a silvery-white soft, metallic substance, potassium, and a gaseous element, oxygen.

The combination in which potash is found in soils is chiefly as silicates of potash. Some kinds of felspar, mica, and granite contain large proportions, as much as 15-20%. Iit also enters into the composition of trap-rock, basalt, and whinstone, though in smaller proportions.

Many plants require a large amount of potash for their food, the only source from which it can be obtained being the soil. This accounts for the fact that wood ashes, which contain carbonate of potash, are so conducive to the healthy growth of clover, beans, potatoes, and other plants whose ashes yield potash in return.

As the rock crumbles, silicates of potash are set free, and rendered available for the plants. Clay, which is chiefly derived from felspar, invariably contains it; and it is partly for this reason that light land, in which potash is usually deficient, is benefitted by claying.

Soda - caustic soda is sodium hydroxide

This is obtained by burning seaweed; and plants growing on the sea-shore are rendered caustic by the same process.

Its most common form, however, is sea-salt, or chloride of sodium. Seakale, asparagus, and similiar plants are benefitted by its use.

Lime - is a calcium-containing (Ca2+) inorganic material in which carbonates, oxides and hydroxides predominate.

Chalk, marble, and limestone are carbonates of lime. Under heat, the carbonic acid is driven out, and pure or caustic lime (Calcium oxide, CaO) remains.

Quicklime sprinkled with water absorbs it; heat is evolved, and it falls to powder, or is slaked. Slaked lime is a white powder, dry to appearance, but contains, in reality, water in an invisible form, chemically combined with lime. If exposed to the air, it attracts carbonic acid from the atmosphere, and becomes partially changed into carbonate of lime.

In its effects on animal and vegetable matters this pure or caustic lime resembles potash and soda, is slower in action, and is used most beneficially on peat land; its excess of organic matter is thus gradually destroyed, and converted into nutritious food for plants.

Salts of lime are found in all ashes of plants; soils, therefore, capable of sustaining vegetable life, must contain lime in some form or other.

Magnesia - a natural mineral of magnesium oxide (Magnesium Mg2+)

The ingredient is never wanting in fertile soils. Magnesian limestone, which is a natural compound of the carbonates of lime and magnesia, contains 30-40%; and in this form it exists in all dolomite and many other solid rocks. Soils containing much carbonate of magnesia absorb moisture with great avidity, and are generally cold soils. Silicate of magnesia enters largely into the composition of serpentine rocks. Soapstone and limestone frequently contain it. Compounds of sulphuric acid and muriatic acid with magnesia are also found in many mineral waters.

Suphate of magnesia, which is the name of the familiar Epsom salts, is formed from the decomposition of dolomitic rocks.

Alumina - Aluminium oxide (Al2O3).
Aluminium is Al3+, so each aluminium ion carries 3 charges.

This is the compound of the metal aluminium with oxygen, or, in other words, oxide of aluminium. It occurs very abundantly in the mineral kingdom, both free and in combination with acids. In its crystallized state it forms the hard mineral known as corundum, and, in combination with oxide of chromium, the saphire and the ruby; and emery is a dark-coloured granular variety of it. In an uncrystallized state it is a white, tasteless, powdery substance, obtained by adding a solution of carbonate of soda to alum.

It constitutes a large proportion of shale and slate rocks, and is a principle ingredient, in combination with silica, in pipe, porcelain, and agricultural clays, to which it gives tenacity and stiffness. It is rarely found in the ashes of plants, and therefore not considered as directly contributing to their nourishment, although useful as a mechanical agent in absorbing ammonia from the atmosphere, and in detaining the volatile as well as the alkaline salts of manures, which would otherwise be dissolved by the first heavy shower, and carried into the subsoil beyond the reach of the roots of the plant.

Iron - is a chemical element with symbol Fe (from Latin: ferrum). Iron compounds are called ferrous.

This metal, both in the black or protoxide, and the red or peroxide state, abounds in all soils, the red being most abundant, and easily observable from the red colour it communicates. Even soils in which the protoxide obtains, which are a bluish-grey colour when brought to the surface, are changed to the red colour by the atmosphere, oxygen uniting with and acting on it. Oxide of iron is found in the ashes of all plants and in the blood of animals.

The presence of iron is easily detected in soils by the ochry deposits in the beds of springs and ditches, where the oxide dissolved in carbonic acid produces the metallic-coloured deposit in question.

Sulphate of iron also occurs in some soils, produced from iron pyrites: such soils are unproductive; for it is a compound of sulphuric acid with protoxide of iron, better known under the name of green vitriol. Lime added to such soils combines with the sulphuric acid, forming gypsum; and sweetens them and removes the injurious properties.

Manganese - Manganese is a chemical element with symbol Mn. It is not found as a free element in nature; it is often found in combination with iron, and in many minerals.

Manganese is also important in photosynthetic oxygen evolution in chloroplasts in plants. The oxygen-evolving complex (OEC) is a part of photosystem II contained in the thylakoid membranes of chloroplasts; it is responsible for the terminal photooxidation of water during the light reactions of photosynthesis, and has a metalloenzyme core containing four atoms of manganese. For this reason, most broad-spectrum plant fertilizers contain manganese.

This metal, in combination with oxygen, associated with oxide of iron, occurs naturally in many soils.

In the ashes of plants traces of it are also found; but iron usually predominates. The ash of the horse chestnut and oak bark is rich in manganese, with no trace of iron.

Silica or Silex - Silicon dioxide, also known as silica (from the Latin silex), is a chemical compound that is an oxide of silicon with the chemical formula SiO2.

This mineral occurs abundantly in nature, either in a free state or in the form of sand, sandstones, flint, chalcedony, rock-crystal, or quartz, and in combination with lime, magnesia, iron, potash, soda, and other minerals. Silica is

• insoluble in hot or cold water, and resists the action of some strong acids; but hydrofluoric acid dissolves it,
• when mixed with soda or potash, and exposed to the heat of a glass furnace.

Silica is dissolved, or rather enters into combination with the alkali, and forms glass; or when the alkali is in excess, it dissolves into water. On the addition of muriatic acid, or sulphuric acid, to a solution of this silicate of potash, the silcate separates into a gelatinous mass, in which form it is soluble in water, and thus becomes the food of plants.

Sulphur - sulphur (sulfur) is a chemical element with symbol S.

Sulphur is an essential element for all life, but almost always in the form of organosulfur compounds or metal sulfides.

Sulfur is increasingly used as a component of fertilizers. The most important form of sulfur for fertilizer is the mineral calcium sulfate. Elemental sulfur is hydrophobic (that is, it is not soluble in water) and, therefore, cannot be directly utilized by plants. Over time, soil bacteria can convert it to soluble derivatives, which can then be utilized by plants. Sulfur improves the use efficiency of other essential plant nutrients, particularly nitrogen and phosphorus. Biologically produced sulfur particles are naturally hydrophilic due to a biopolymer coating. This sulfur is, therefore, easier to disperse over the land (via spraying as a diluted slurry), and results in a faster release.

Plant requirements for sulfur are equal to or exceed those for phosphorus. It is one of the major nutrients essential for plant growth, root nodule formation of legumes and plants protection mechanisms. Sulfur deficiency has become widespread in many countries in Europe.

This compound, in the form of sulphuric acid, enters into the composition of all cultivated soils, chiefly in combination with limestone, magnesia, potash, and other bases.

With hydrogen it forms sulhuretted hydrogen, a remarably disagreeable-smelling gas, the product of the decompostion of organic matter contained in the soil and impregnating many medicinal waters, as at Harrogate in North England.

Phosphorus - Phosphorus is a chemical element with symbol P .

Phosphorus is essential for life. Phosphates (compounds containing the phosphate ion, PO4−3) are a component of DNA, RNA, ATP, and also the phospholipids, which form all cell membranes. Demonstrating the link between phosphorus and life, elemental phosphorus was first isolated from human urine, and bone ash was an important early phosphate source. Phosphate minerals are fossils. Low phosphate levels are an important limit to growth in some aquatic systems. Phosphate is needed to replace the phosphorus that plants remove from the soil, and its annual demand is rising nearly twice as fast as the growth of the human population.

This ingredient is a soft, wax-like, highly inflammable substance, which combines with atmospheric oxygen, giving rise to phosphoric acid, which enters into the composition of all our cultivated plants, and is essentially necessary to a healthy condition of vegetable life.

Phosphorus exists in trap-rock, granite, basalt and other igneous rocks, and in lime, ironstone and most minerals.

Chlorine - Chlorine is a chemical element with symbol Cl. In the form of chloride ions, chlorine is necessary to all known species of life. Chloride is one of the most common anions in nature.

This is a highly-noxious, suffocating, yellowish, gaseous element, particularly disagreeable in smell.

In soils it is found in combination with such bases as chloride of sodium, or common salt. It is more necessary as a plant-food to root crops rather than to cereals.

Some of the affects of the above 11 chemicals on the following soils:-

Sandy Soils - If you try to adjust the soil texture by adding silt or clay to a sandy soil, you’ll see some improvement, but most of it will just flush through the soil. There’s not enough organic matter to keep these fine-textured soil components from washing out. Increasing soil organic matter is the key to gardening in sandy soil. You have to make the soil more “sticky”, so water and nutrients don’t just flush through every time it rains.

My suggestion:-
If you fill 30% of cement mixer with water, add 20% of clay and mix till a slurry. Add organic matter and your sandy soil and mix, keeping it as a slurry. Pour into wheelbarrow and move to where it is required and tip the wheelbarrow, spread the result with a rake, before repeating the process for the rest of the ground to be altered. The worms and rain will transport this material down and that will create a loam which is best for your plants as shown in the diagram at the top of this page.

Sandy soils are loose, friable, open and dry, and for that reason easily cultivated. They rest chiefly on the old red sandstone, and granite and coal formations.

Where alumina and calcareous matter are absent, however, they are nearly barren, they absorb manures without benefit to the land.

Where alumina and lime exist, they are more compact and adhesive, and grow good crops of beans, peas, spring wheat, and turnips.

They are capable of improvement by admixture with clay, marl, chalk, and other adhesive soils, which communicate their constituent properties to them

Calcareous Soils - Calcareous soils have often more than 15% CaCO3 (Calcium carbonate) in the soil. Phosphorous is often lacking in calcareous soils. Calcareous soils usually suffer from a lack of micronutrients, especially zinc and iron. Heavy applications of animal manure are helpful in preventing deficiency of iron and zinc.

Calcareous is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. Calcareous soils are relatively alkaline, in other words they have a high pH.

The availability of N, P, K, Mg, Mn, Zn, and Fe to citrus decreases when soil CaCO3 concentration increases to more than about 3% by weight. These soils generally have a pH value in the range of 7.6 to 8.3. Phosphorus fertilizer applied to calcareous soils becomes fixed in sparingly soluble compounds over time. To maintain continuous P availability, P fertilizer should be applied on a regular, but not necessarily frequent, basis.

Calcareous soils resting on the upper chalk formation are usually deep, dry, loose, friable, and fertile in their nature, but others, resting on the shaly oolite, are stony, poor, thin soils.

Where pure clay is present in such soils, they are called loams or calcareous clays; where silica is in excess, they are termed calcareous sandy soils.

Leguminous plants, as peas, beans, vetches, saintfoin, and clover, do well on such soils, lime being essential to their growth.

Clay Soils - Interesting 4 page article applying compost etc to improve clay soil.

To improve that soil as the quickest solution, I would add a 1 cm (0.5 inch) depth of sharp washed sand, a 1 cm depth of chalk (lime) and 10 cm (4 inch) depth of organic compost and leave it to work itself in from that application in early spring. 2 months later add 3 inches (7.5 cm) depth of cow manure to provide further nutrients.

Clay soils are characterised by stiffness, impenetrability, great power of absorbing and retaining moisture, and great specific gravity; they are, consequently, cold, stiff, heavy, and impervious, costly to cultivate, and often unproductive.

Perfect drainage,
burning the soil with wood faggots, branches of trees, grass sods, and vegetable refuse, and
mixing chalk and sand,
are the only remedies. Burning is the most efficient remedy; the burnt clay acting chemically as a manure, its contstituents being rendered more soluble. Provided a moderate heat has been applied to the process, the potash is rendered soluble, and liberated from the clay in which it occurs in an insoluble combination. Thus treated, clay soils become the most fertile for all heavy crops.

The following weeds indicate what the soil is that they naturally grow on
as detailed in Encyclopedia of Gardening by J.C. Loudon and published in 1827:-

Argillaceous or Clayey Soil

Common coltsfoot indicates blue clay

Tussilago farfara

The most certain and universal sign of a clayey soil, and the chief plant found on alum grounds of Britain, France, and Italy

Goose tansy (Goosegrass)

Potentilla anserina

Silvery-leaved tansy (Hoary cinquefoil)

Potentilla argentea

Creeping tansy (Creeping cinquefoil)

Potentilla reptans

Yellow meadowrue (Common meadow-rue)

Thalictrum flavuum

Sedge

Carex

many species

Rush

Juncus

various species

Tuberous bitter vetch (Bitter vetch, Heath Pea)

Orobus tuberosus (Lathyrus linifolius subsp. montanus)

Greater bird's-foot trefoil

Lotus major (Lotus uliginosus)

Small-horned trefoil (Common birdsfoot trefoil)

Lotus corniculatus

Common soapwort (Soapwort)

Saponaria officinalis

Calcareous Soil

Spiked speedwell

Veronica spicata

Little bedstraw

Galium pusillum

Common gromwell

Lithospermum officinal

Purple-blue gromwell (Purple gromwell)

Lithospermum purpureo-caeruleum

Clustered bell-flower

Campanula glomerata

Hybrid bell-flower (Venus's Looking-glass)

Specularia hybrida (Legousia hybrida)

Round-headed rampion

Phyteuma orbiculare (Phyteuma tenerum)

Lychnitis mullein (White Mullein)

Verbascum lychnitis

Wayfaring tree

Viburnum lantana

Common berberry (Barberry)

Berberis vulgaris

Common dwarf sun-rose (Common Rock-Rose)

Helianthemum vulgare (Helianthemum nummularium, Helianthemum chamaecistus)

Common pulsatilla anemone (Pasque Flower)

Anemone pulsatilla

White vine, virgin's bower or traveller's joy

Clematis vitalba

Cultivated sainfoin (Sainfoin)

Onobrychis sativa (Onobrychis viciifolia)

Sandy or Siliceous Soil

Three-leaved speedwell (Fingered Speedwell)

Veronica triphylla (Veronica triphyllos)

Spring speedwell

Veronica verna

Italian viper's bugloss (Pale Bugloss)

Echium plantagineum contains pyrrolizidine alkaloids and is poisonous.[10] When eaten in large quantities, it causes reduced livestock weight and death, in severe cases. Paterson's curse can kill horses[11] and irritate the udders of dairy cows and the skin of humans. After the 2003 Canberra bushfires a large bloom of the plant occurred on the burned land, and many horses became ill and died from grazing on it.[12] Because the alkaloids can also be found in the nectar of Paterson's curse, the honey made from it should be blended with other honeys to dilute the toxins.

Echium italicum

Smooth rupture wort

Herniaria glabra

Hairy rupture wort - Herniaria hirsuta is a species of flowering plant in the pink family known by the common name hairy rupturewort. It is native to Eurasia and North Africa, and it is known on other continents, including North America, as an introduced species.

Herniaria hirsuta

English catchfly (Small-flowered Catchfly)

and others in the Pink Family Pages 1 and 2

Silene anglica

and other species

Red sandwort indicates poor sand

Arenaria rubra

Cornfield spurrey (Corn spurrey)

Spergula arvensis

Hybrid poppy (Bristly Poppy)

Papaver hybridum

Scarlet poppy (Pale Poppy)

Papaver argemone

Ferruginous Soil - Ferrallitisation is the process in which rock is changed into a soil consisting of clay (kaolinite) and sesquioxides, in the form of hydrated oxides of iron and aluminium. In humid tropical areas, with consistently high temperatures and rainfall for all or most of the year, chemical weathering rapidly breaks down the rock. This at first produces clays which later also break down to form silica. The silica is removed by leaching and the sesquioxides of iron and aluminium remain, giving the characteristic red colour of many tropical soils. Ferrallitisation is the reverse of podsolisation, where silica remains and the iron and aluminum are removed. In tropical rain forests with rain throughout the year, ferrallitic soils develop. In savanna areas, with altering dry and wet climates, ferruginous soils occur.

Garden sorrel indicates the presence of iron or peat (Sheep's Sorrel)

Rumex acetosa

Wood sorrel

Oxalis acetosella

Peaty Soil - This kind of soil is basically formed by the accumulation of dead and decayed organic matter, it naturally contains much more organic matter than most of the soils. It is generally found in marshy areas. Now the decomposition of the organic matter in Peaty soil is blocked by the acidity of the soil. This kind of soil is formed in wet climate. Though the soil is rich in organic matter, nutrients present are fewer in this soil type than any other type. Peaty soil is prone to water logging but if the soil is fertilized well and the drainage of the soil is looked after, it can be the ideal for growing plants.

Bilberry

Vaccinum myrtillus

Bleaberry (Northern bilberry)

Vaccinum uliginosum

Cranberry

Oxycoccus palustris

Heath - See Heath Family and Erica

Erica

Awl leaved spurrey (Heath Pearlwort)

Spergula subulata
(Sagina subulata)

Officinal septfoil (Tomentil)

Tormentilla officinalis (Potentilla erecta)

Saline or Salt Soil - Researchers at the University of California at Davis are breeding barley for culture with sea water irrigation (Epstein, 1976). Lines have been developed which survive and set seed (yields in the order of 1188 kg/ha) under irrigation with undiluted sea water. Similar breeding is underway with wheat. Table 18 states tolerance of fruit varieties and root stocks to Chloride levels.

Leaching is the only practical way of removing excess salts.  This is effective only to the extent that water moves down through the soil profile and beneath the root zone (drainage must be good). The amount of salts removed depends on the quantity and quality of water leached through the soil profile during a single irrigation period. Water should be low in salts (high quality) and must not run off the surface. It should be applied slowly so amounts do not exceed the ability of the soil to take in water (infiltration rate). The following amounts of water applied in a single, continuous irrigation will dissolve and decrease soil salts by these fractional amounts:

• 6 inches of water will leach about ½ the salt

• 12 inches of water will leach about 4/5 of the salt.

• 24 inches of water will leach about 9/10 of the salt.

Salty soils are not reclaimable when the soil’s clay content, compaction, or hardpan prevents leaching.

Glasswort - Glassworts Family

Salicornia

Marine wrackgrass (Common eel-grass)

Zosteria marina

Sea ruppia (Tassel Pondweed)

Ruppia maritima

Sea lungwort (Oyster Plant)

Pulmonaria maritima (Mertensia maritima)

Soldanella-leaved beanbind (Sea Bindweed)

Calystegia soldanella

Whorled knotgrass (Coral necklace)

Illecebrum verticillatum

Sea goosefoot (Common seablight)

Chenopodium maritimum (Suaeda maritima)

Shrubby goosefoot (Shrubby seablite)

Chenopodium fruticosum (Suaeda fruticosa)

Kali saltwort (Saltwort)

Salsola kali

Whorl-leaved honeywort (Whorled caraway)

Sison verticillatum
(Carum verticillatum)

Marine sandwort

Arenaria marina

Fringed orach (Frosted orache)

Atriplex laciniata

Aquatic or Moist Soil - Standing water under wading bird rookeries is critical to limiting predation and enhancing nest success. Draining impoundments while wading birds are actively nesting is strongly discouraged, regardless of other management needs. Appendix 1 gives a waterfowl food value guide for common moist-soil plants in the Southeast of USA.

Marsh marigold

Caltha palustris

Common mare's-tail (Marestail)

Hippuris vulgaris

Common butterwort

Pinguicula vulgaris

European water-horehound (Gipsywort)

Lycopus Europeus

Dioecious valerian (Marsh valerian)

Valeriana dioica

Marsh violet

Hottonia palustris
(Viola palustris)

Valerandi's brookweed (Brookweed)

Samolus valerandi

Marsh thysselinum (Milk parsley)

Thysselium palustre (Peucedanum palustre)

Square-stalked willow herb
(Square-stemmed willow-herb)

Epilobium tetragonum

Willow-like lythrum (Purple Loosestrife)

Lythrum salicaria

Tongue-leaved crowfoot (Greater Spearwort)

Ranunculus lingua

Spearwort

Ranunculus flammeus

Very Dry Soil - Drought-resistant plants. Overcoming dry soils in Australia with list of drought-tolerant plants.

Red sandwort indicates poor sand

Arenaria rubra

Garden sorrel (Common sorrel)

Rumex acetosa

Wild thyme

Thymus serpyllum

Basil-leaved or common acynos, a thyme-like plant (Basil thyme)

Acynos vulgaris (Acynos is Basil-thyme and Acynos vulgaris is Common basil-thyme.

Field trefoil (Haresfoot clover)

Trifolium arvense