Seed Storage

The keeping of seeds to maintain their viability and future germination potential. Seeds can be stored in various ways, including natural dry storage, being packaged in bags, which are then kept in a dry location (for example a storage shed or building of various construction materials), in cool conditions. This is probably the most common storage method used by grounds managers. Most grass seed stored in this way would want to be used within 12-months as the germination and establishment potential of the grass seed will decrease significantly over time. Other methods which might be used on an industrial scale or for research purposes are the use of seed banks; frozen storage; refrigerated storage or controlled atmosphere situations such as in rooms or containers.

  Self-Pollination

The transfer of pollen grains from the anther to a stigma on the same plant. Many annual grasses (e.g. Annual meadow grass) and agricultural crops (e.g. Oat, Barley) are self-pollinating, although the majority of perennial grasses are cross-pollinated, however, some grasses can have both pollination methods depending on prevailing conditions, such as if the stigma and anther are ‘active’ at the same time on the same plant. (See also Table 1, p.19 in, ‘Pan, K., Marshall, L., Biesmeijer, K., & R. de Snoo, G. (2022). The distributions of insect, wind and self pollination of plants in the Netherla

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  Shade

A reduction in the amount of light reaching a plant. Less shade produces less energy available for photosynthesis and growth; this results in turf that is less dense, with thinner leaves, weaker root development and a more easily worn surface.

  Shear Strength

The ability of a material, such as a soil or grass surface, to resist tearing. It is used to measure the ability of a surface to hold together and to identify at what point it fails.

  Size Grade Number

The diameter (given as millimetres x 100), of the median of the fertiliser granules of an analysed batch of fertiliser. Where a size grade number (which is frequently referred to by its acronym of SGN) of 250 is quoted, this means that 50% of the sample will be greater than 2.5mm and 50% below 2.5mm diameter.

  Slow Re-growth

A characteristic which is used to evaluate the relative slow speed of growth of a turfgrass cultivar. A cultivar and sward which has a slow regrowth rate will require less frequent mowing, being more suited to low maintenance areas and surfaces where budgets are limited or where usage on a sports pitch is not excessively high.

  Sod

An alternative and within the UK an old-fashioned term for turf.

  Sodium Adsorption Ratio

A measure of the concentration of sodium and its relationship with calcium and magnesium in irrigation, especially extracted from bore holes or from recycled water, or soil water to determine soil or water salinity. The SAR value is the ratio of the amount of sodium (measured in meq/L) divided by the square root of one-half of the amount of calcium and magnesium. SAR=〖Na〗^+/√((〖Ca〗^(+2)+ 〖Mg〗^(+2))/2) The hazard presented from the water will depend not just on the SAR value but also the value of the electrical conductivity of the water.

  Soil Balance Sheet

A tabulated data sheet with numerous columns for data recording to help estimate water requirements of a plant. The table will typically include columns for Potential Evapo-transpiration; Estimated actual Evapo-transpiration; Rainfall; Irrigation; Drainage; Soil Moisture or Water Deficit. A similar Soil Balance Sheet can also be devised and used for nutrient requirements; especially Nitrogen, Phosphorus and Potassium.

  Soil Ecology

The diversity and interactions of soil organisms and the effect they have on plant growth and development and conditions, for example soil structure and drainage potential, of the soil profile.