To the uninitiated the soil under our feet is a lifeless, uninteresting dirty media, which sticks to their boots and soils their clothes. To us gardeners, there beneath us lies a vast biological factory and nutrient reserve, which must be nurtured, restocked and cultivated. Apart from the obvious soil fauna, i.e. insects and earthworms of which there are ten common species in Britain, depositing an extra 5mm. of topsoil per hectare per year, in the form of worm casts. There are also vast numbers of bacteria, estimated at 1,000 million in each gram of fertile soil and despite their microscopic size the top 150mm. of topsoil carries about one tonne of bacteria per hectare.
Soil is formed by a number of evolutionary changes taking place, the most important of which is weathering. From the moment rocks are formed and exposed to the elements they are subjected to erosion and the movement of rock fragments in the soil. Weathering can be further split into two main causes:
All these various factors are instrumental in the fragmentation of rock, which is the first stage of soil formation. Plant roots then explore the small fissures in the rock and prize them wide open. The plants die and then bacteria work on the remains, and after thousands of years a living soil is developed.
Organic soils, which are made up of partly decayed plants, are called ‘PEATS’. Soils made up of largely inorganic substances, i.e. different size rock fragments, with some organic matter present are called ‘MINERAL SOILS’.
SOIL TEXTURE: This is usefully
defined as the relative proportions of the sand, silt and clay particles
in the soil.
HUMUS: This is essential to
maintaining soil structure. This vital ingredient is a sticky black liquid
which remains in the soil when plant remains (organic matter) are decayed
or broken down by bacteria. It is responsible for binding together the
mineral particles and making the desirable ‘crumb’ structure.
SOIL STRUCTURE: This is the
process of the arrangement of particles in the soil. The structure
formation turns mineral particles into crumbs.
In a natural plant community, when plants
die, they decompose and nutrients are recycled and become available to the
plants again. When, however, a crop is harvested and removed from
the soil, the nutrients are lost, and unless returned in some other form,
the soil becomes poor and infertile. Nutrients are also leached out of the
soil by rain.
Boron, Zinc, Copper, Iron, Sodium, Manganese, Aluminium, and Molybdenum. These are present in plants in very small amounts but are just as essential for healthy growth as the major nutrients. THEY CAN BE TOXIC if present in too high a concentration. Most mineral soils have adequate reserves of trace elements.
Nitrogen, Phosphorus, Potassium, Calcium and Magnesium become more available as pH increases (more alkaline) though Phosphorus is less available above pH 7. Iron, Manganese, Boron Copper & Zinc become more available as pH falls (more acid), though Manganese, Boron, Copper & Zinc become less available below pH 5.
Calcium and Magnesium are nutrients which not only become more available at higher pHs, but are the main components of LIME which is used to adjust soil pH to a level just below neutral (pH 7) pH 6.5 is found to be most favourable for the availability of all plant nutrients and is the pH to which most soils and soil based composts are adjusted, Nitrifying bacteria work best above pH 6 therefore Nitrogen is more available.
As the reader can now appreciate the importance of correct pH is vital to healthy plant growth, and the importance of having your soil pH accurately measured and obtaining expert advice on it’s correction is first priority at the start of the growing season.
Growers can as well as having the pH of their soil tested, have a major nutrient analysis.
We at HORTIBOTANIC UK will be happy to carry out this work. All the gardener has to do is to send a soil sample to us, (instructions for sample collection etc. is contained in our free fact sheet, S.A.E. please, ALTERNATIVELY ON OUR WEBSITE) telling us which plants are to be grown, and leave the rest to us.
You will receive, (within 7 working days from receipt of sample) a detailed test report, containing details of nutrient levels, actual soil pH, how to adjust if necessary, how to correct any nutrient deficiencies, with what fertiliser, and in what amounts. Also included is an assessment of soil composition, soil type, and workability and how to improve if necessary, we will even tell you how much organic matter it contains at a small extra charge if you require it.
We test hundreds of samples from all over the U.K. every year from professional growers to major exhibitors to weekend gardeners, so you can be assured of a professional service at a reasonable price with expert advice.
OPTION 1: Standard Analysis. includes pH test - tests for N, P, K. and a full assessment of Soil Composition etc
OPTION 2: Exhibition Analysis. includes pH test - tests for N, P, K. and a full assessment of Soil Composition etc., PLUS Test for Magnesium and Soil Conductivity, (Soil Conductivity is measured electrically and gives a measure of the salt concentrations in the soil. If salt concentrations are too high, symptoms of water stress become apparent. Salt concentrations can occur from over zealous application of fertilisers or in protected culture, greenhouse or poly-tunnel, which are not exposed to rainfall etc.)
Also available: ORGANIC MATTER DETERMINATION. The results are expressed as a percentage.
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