ARCHIVE: Fertiliser Manual (RB209)



Negatively charged form of an atom or molecule for example nitrate (NO3-) and sulphate (SO4 2-).

Available (nutrient) Form of a nutrient that can be taken up by a crop immediately or within a short period so acting as an effective source of that nutrient for the crop.
Bandspreading Application of fertiliser or slurry in bands along a row of seeds or crop plants.
Biosolids Treated sewage sludge.
Broiler/turkey litter A mixture of bedding material and poultry excreta which is sufficiently dry to be stored in a stack without slumping.
Calcareous soil Soil that is alkaline due to the presence of free calcium carbonate or magnesium carbonate or both.
Cation Positively charged form of an atom or molecule for example potassium (K+), calcium (Ca2+), magnesium (Mg2+) and ammonium (NH4+).
Cation exchange capacity Capacity of the soil to hold cations by electrostatic forces. Cations are held at exchange sites mainly on clay particles and organic matter.
Clay Finely divided inorganic crystalline particles in soils, less than 0.002mm in diameter.
Closed period Period of the year when nitrogen fertilisers or certain manures should not be applied unless specifically permitted. Closed periods apply within NVZs.
Coefficient of variation (CV) (fertiliser or manure spreading) Measure of the unevenness of application of fertilisers or manures. CV of 0% indicates perfectly even spreading, unachievable in practice. Correct operation of a well set-up spreader should give a CV of 10% for fertilisers and 25% for manures under field conditions.
Compost Organic material produced by aerobic decomposition of biodegradable organic materials.
Content Commonly used instead of the more accurate ‘concentration’ to describe nutrients in fertiliser or organic manure. For example, 6 kg N/t often is described as the nitrogen content of a manure.
Cover crop A crop sown primarily for the purpose of taking up nitrogen from the soil and which is not harvested. Also called green manure.
Crop available nitrogen The total nitrogen content of organic manure that is available for crop uptake in the growing season in which it is spread on land.
Crop nitrogen requirement The amount of crop available nitrogen that must be applied to achieve the economically optimum yield.
Denitrification Microbial conversion of nitrate and nitrite in anaerobic soil to nitrogen gas and some nitrous oxide.
Deposition Transfer of nutrients from the atmosphere to soil or to plant surfaces. The nutrients, mainly nitrogen and sulphur, may be dissolved in rainwater (wet deposition) or transferred in particulate or gaseous forms (dry deposition).
Digestate Organic material produced by anaerobic digestion of biodegradable organic materials. May be separated into liquid and fibre fractions after digestion.
Dirty water Lightly contaminated run-off from lightly fouled concrete yards or from the dairy/parlour that is collected separately from slurry. It does not include liquids from weeping-wall stores, strainer boxes, slurry separators or silage effluent
which are rich in nitrogen and regarded as slurries.
Economic optimum (nitrogen rate) Rate of nitrogen application that achieves the greatest economic return from a crop, taking account of crop value and nitrogen cost.
Efficiency factor (manures) Percentage of total nitrogen in a manure that is available to the crop for which the manure was applied. There are mandatory minimum values in NVZs for use when estimating the nitrogen availability of manures.
Erosion Movement (transport) of the soil by running water or wind.
Eutrophication Enrichment of ecosystems by nitrogen or phosphorus. In water it causes algae and higher forms of plant life to grow too fast. This disturbs the balance of organisms present in the water and the quality of the water concerned. On land, it can stimulate the growth of certain plants which then become dominant so that natural diversity is lost.
Excess rainfall Rainfall between the time when the soil profile becomes fully wetted in the autumn (field capacity) and the end of drainage in the spring, less evapo-transpiration during this period (i.e., water lost through the growing crop).
FACTS UK national certification scheme for advisers on crop nutrition and nutrient management. Membership renewable annually. A FACTS Qualified Adviser has a certificate and is a member either of the FACTS Annual Scheme or of the BASIS Professional Register.
Farmyard manure (FYM) Livestock excreta that is mixed with straw bedding material that can be stacked in a heap without slumping.
Fertiliser See Manufactured fertiliser.
Fluid fertiliser Pumpable fertiliser in which nutrients are dissolved in water (solutions) or held partly as very finely divided particles in suspension (suspensions).
Frozen hard Soil that is frozen for more than 12 hours. Days when soil is frozen overnight but thaws out during the day do not count.
Granular fertiliser Fertiliser in which particles are formed by rolling a mixture of liquid and dry components in a drum or pan. Typically, particles are in the 2 – 4mm diameter range.
Grassland Land on which the vegetation consists predominantly of grass species.
Greenhouse gas Gas such as carbon dioxide, methane or nitrous oxide that contributes to global warming by absorbing infra-red radiation that otherwise would escape to space.
Green manure See Cover crop.
Heavy metal Cadmium, copper, lead, mercury, nickel or zinc. Elements that are potentially toxic to mammals above critical levels. Copper, nickel and zinc are required by plants in very small amounts.
Incorporation A technique (discing, rotovating, ploughing or other methods of cultivation) that achieves some mixing between an organic manure and the soil. Helps to minimise loss of nitrogen to the air through volatilisation, and nutrient runoff to surface waters.
Inorganic fertiliser Manufactured fertiliser that contains only inorganic ingredients or urea.
Layer manure Poultry excreta with little or no bedding.
Leaching Process by which soluble materials such as nitrate or sulphate are removed from the soil by drainage water passing through it.
Ley Temporary grass, usually ploughed up one to five years (sometimes longer) after sowing.
Lime requirement Amount of standard limestone needed in tonnes/ha to increase soil pH from the measured value to a higher specified value (often 6.5 for arable crops). Can be
determined by a laboratory test or inferred from soil pH.
Liquid fertiliser See Fluid fertiliser.
Livestock manure Dung and urine excreted by livestock or a mixture of litter, dung and urine excreted by livestock, even in processed organic form. Includes FYM, slurry, poultry litter, poultry manure, separated manures, granular or pelletised manures.  
Macronutrient See Major nutrient or Secondary nutrient.  
Maintenance application (phosphate or potash) Amount of phosphate or potash that must be applied to replace the amount removed from a field at harvest (including that in any straw, tops or haulm removed).  
Major nutrient Nitrogen, phosphorus and potassium that are needed in relatively large amounts by crops (see also Secondary nutrients and Micronutrients).  
Manufactured fertiliser Any fertiliser that is manufactured by an industrial process. Includes conventional straight and NPK products (solid or fluid), organo-mineral fertilisers, rock phosphates, slags, ashed poultry manure, liming materials that contain nutrients.
Manure See Livestock manure and Organic manure.
Micronutrient Boron, Copper, Iron, Manganese, Molybdenum, Zinc that are needed in very small amounts by crops (see also Major nutrients and Micronutrients). Cobalt and selenium are taken up in small amounts by crops and are needed in human
and livestock diets.
Mineral nitrogen Nitrogen in ammonium and nitrate forms.
Mineralisable nitrogen Organic nitrogen that is readily converted to ammonium and nitrate by microbes in the soil, for example during spring.
Mineralisation Microbial breakdown of organic matter in the soil, releasing nutrients in crop-available, inorganic forms.
Neutralizing value (NV) Percentage calcium oxide (CaO) equivalent in a material. 100kg of a material with a neutralising value of 52% will have the same neutralising value as 52kg of pure CaO. NV is determined by a laboratory test.
Nitrogen uptake efficiency Uptake of nitrogen from soil, fertiliser or manure expressed as a percentage of nitrogen supply from that source.
Nitrogen use efficiency Ratio of additional yield produced to the amount of nitrogen applied to achieve that increase. Often expressed as kg additional yield per kg N applied.
Nitrous oxide (N2O) A potent greenhouse gas that is emitted naturally from soils. The amount emitted is related to supply of mineral nitrogen in the soil so increases with application of manures and fertilisers, incorporation of crop residues and growth of
legumes and is greater in organic and peaty soils than in other soils.
Offtake Amount of a nutrient contained in the harvested crop (including straw, tops or haulm) and removed from the field. Usually applied to phosphate and potash.
Olsen P Concentration of available P in soil determined by a standard method (developed by Olsen) involving extraction with sodium bicarbonate solution at pH 8.5. The main method used in the England, Wales and Northern Ireland and the basis for the Soil Index for P.
Organic manure Any bulky organic nitrogen source of livestock, human or plant origin, including livestock manures.
Organic soil Soil containing between 10% and 20% organic matter (in this Manual). Elsewhere, sometimes refers to soils with between 6% and 20% organic matter.
Peaty soil (peat) Soil containing more than 20% organic matter.
Placement Application of fertiliser to a zone of the soil usually close to the seed or tuber.
Poultry litter See Broiler/turkey litter.
Poultry manure Excreta produced by poultry, including bedding material that is mixed with excreta, but excluding duck manure with a readily available nitrogen content of 30% or less.
Prilled fertiliser Fertiliser in which particles (prills) are formed by allowing molten material to fall as droplets in a tower. Droplets solidify during the fall and tend to be more spherical and somewhat smaller than granules (see Granular fertiliser).
Readily available nitrogen Nitrogen that is present in livestock and other organic manures in molecular forms that can be taken up immediately by the crop (ammonium or nitrate, or in poultry manure uric-acid N). High in slurries and poultry manures (typically 35-70% of total N) and low in FYM (typically 10-25%).
Removal See Offtake.
Run-off Movement of water across the soil surface which may carry nutrients from applied manures or fertilisers and with soil particles.
Safe Sludge Matrix Guidance on use of sewage sludge for different crops agreed by Water UK and the British Retail Consortium.
Sand Soil mineral particles larger than 0.05mm.
Secondary nutrient Magnesium, sulphur, calcium or sodium that are needed in moderate amounts by crops.
Silt Soil mineral particles in the 0.002 – 0.05mm diameter range.
Slurry Excreta of livestock (other than poultry), including any bedding, rainwater and washings mixed with it, that can be pumped or discharged by gravity. The liquid fraction of separated slurry is also defined as slurry.
SNS Index Soil Nitrogen Supply expressed in seven bands or Indices, each associated with a range in kg N/ha.
Soil Index (P, K or Mg) Concentration of available P, K or Mg, as determined by standard analytical methods, expressed in bands or Indices.
Soil Mineral Nitrogen (SMN) Ammonium and nitrate nitrogen measured by the standard analytical method and expressed in kg N/ha.
Soil Nitrogen Supply (SNS) The amount of nitrogen (kg N/ha) in the soil that becomes available for uptake by the crop in the growing season, taking account of nitrogen losses.
Soil organic matter Often referred to as humus. Composed of organic compounds ranging from undecomposed plant and animal tissues to fairly stable brown or black material with no trace of the anatomical structure of the material from which it was derived.
Soil texture Description based on the proportions of sand, silt and clay in the soil.
Soil type Description based on soil texture, depth, chalk content and organic matter content.
Solid manure Organic manure which can be stacked in a freestanding heap without slumping.
Target Soil Index Lowest soil P or K Index at which there is a high probability crop yield will not be limited by phosphorus or potassium supply. See Soil Index (P, K or Mg).
Tillage land Land that is not being used for grass production and is sown with a crop.
Trace element See Micronutrient.
Volatilisation Loss of nitrogen as ammonia from the soil to the atmosphere.
Water-soluble phosphate Phosphate, expressed as P2O5, that is measured by the statutory method for fertiliser analysis. Not necessarily a measure of available phosphate – high water-solubility indicates high availability but low water-solubility does not necessarily indicate low availability.
Weathering Breakdown of soil mineral particles by physical or chemical processes. Enhanced by variation in temperature and moisture. A significant mechanism for release of potassium from clay minerals.

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