Nutrient Loss from a Soil

There are three main ways in which nutrients might be lost from a soil: 1. Through mower clippings or from scarification / verticutting arisings. 2. Leaching of nutrients from a soil profile, especially from a very sandy soil. 3. Where some nutrients are lock-up though soil pH, or where some nutrients, where present in excessive quantities, create an imbalance in the soil and reduce the availability of other nutrients. These situations can be classed as a temporary loss as changing soil pH or correcting imbalances can make other nutrients more available.

  O Horizon

A soil profile layer, often at the surface, which is dominated by organic matter. The organic layer might be of uniform consistency, especially where the pH is around 7.0 and this is termed mull, whilst in contrast in very acidic soils there could be up to three distinct organic layers, a surface litter layer, then fermentation layer and then a lower humus layer, primarily due to the relatively slow breakdown of organic matter in these soil conditions. This is called mor and might be similar to some thatch layers on very acidic golf fairways. Organic horizons that exhibit intermediate stages

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  Open Ditch Drainage System

A ditch which is not filled in with pipework and gravel but kept open to the elements. This might be considered as an outlet for lateral or main drain pipework, or for mole drains. Other situations might include: • Using on silty or unstable soils, such a Gley soils, where subsurface drainage might be unsuitable; • To remove larger volumes of water than can be achieved with pipework; or • Where resources are very limited and excavating or utilizing and existing ditch is the quickest and cheapest option.

  Organic Nitrogen

Nitrogen compounds within a soil in organic form, including amino acids, chitin, peptides, and proteins, being components that arise from dead bacteria, fungi and invertebrates, as well as form root exudates and dead roots, along with any applied organic material as part of a top-dressing. The nitrogen is only made available (as inorganic nitrogen) to plants following breakdown of the compounds as part of the mineralisation process by micro-organisms. Nearly all nitrogen within a soil is held as organic nitrogen.

  Organic Soil

This includes a range of soil classifications, depending upon the relative proportion of organic matter, degree of humification and moisture content. Soils that are wet will have low rates of decomposition and this results in a build-up of organic material, resulting in bogs or fens, both being peats. Organic soils will typically have a depth of at least 400mm and provide a mechanism to capture and store significant quantities of carbon dioxide, helping to mitigate climate change, and also storing vast quantities of water helping to reduce flood risk. The percentage of organic matter withi

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  Outfall

A point of discharge of water from a drainage system. Where an outfall discharges into a ditch, stream or river, it will have to be in accordance with water authority requirements. This will typically consist of a concrete structure with a splash plate to prevent erosion of the watercourse embankment.

  Over Acidic Soil

A soil which has a negative impact on the growth of a plant. In a turfgrass situation, an over acidic soil will lead to a thin sward; a more easily worn surface; weaker grass growth; an increased thatch layer, and an increase in drought susceptibility.

  Oxidation

A chemical weathering process, which is a reaction process in which minerals, or elements, gain an oxygen molecule, through the exchange of electrons during the process of combining with oxygen. A common example is that of iron reacting with oxygen to form rust (iron oxide), with decomposition of organic matter also being an oxidation process. The typical process would occur as follows: • Oxygen in the soil profile reacts with minerals or elements in the soil. This can be enhanced by the activities of oxidising soil micro-organisms. • Chemical changes occur, with the result being the form

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  Pan

A dense and often solid layer of soil which limits the infiltration and percolation of water. Pans can be caused by compaction, the filtering down of fine clay particles to form a distinct dense layer, or the reaction of elements such as iron or sodium to form a solid mass within a soil profile. This term is more typically referred to as a soil pan, clay pan, or hardpan.

  Particle Density

The solid mass of dry soil particles in a specific volume. This measure excludes any air pores and can be considered as a solid block of a material. It is expressed as the measure, grams per cubic centimetre.