Describe how plant nutrients can be provided and maintained.

Identify the characteristics of organic and inorganic sources of nutrients.

NUTRIENT SOURCE

The benefits and limitations of nutrient sources:

Environmental: Bulky organic; Good recycling of organic material; Runoff from heaps can pollute waterways; Fertilises; Issue of energy used in manufacture; Some quick acting materials can leach and pollute waterways (algae bloom); Salt residues can build up in soils or compost to toxic levels.

Health and Safety: All weight of handling; Bulky organic pathogen content? (hygiene); Allergy to contents possible Attracts dogs cats & foxes to the plants Bone meal unsterilized may carry CJD – all commercial types now sterilised Imported organic anthrax in unsterilized blood and bone meal

Timing of application: Bulky organic winter digging in; Spring – use as mulches; Fertilisers: Base – use in preparation stage; Top/liquid/foliar – apply to growing crop as required; Lawns – spring and summer, high nitrogen up to August; Spring cabbage – late March to give a boost to growth after the winter leaching of nutrients from the soil.

Variability of the material: Bulky organics nutrient content very variable; Organic fertilisers slightly variable; Inorganic fertiliser stable content.

ORGANIC NUTRIENT

Material that once was living; Organic must contain Carbon; Often requiring bacterial activity to release the nutrient to the plant (can be considered slow acting); Bulky – farmyard manures/compost: A large volume of organic matter with a small amount of nutrients; Applied in large volumes so the low nutrient value becomes a useful amount; Has a high effect on the soil as an organic matter (building up soil structure/ becoming humus).

Organic Fertiliser: Processed/ground-up organic material; Hoof and horn 14% N, 2% P, bone meal 4% N, 20 % P; A small volume of organic matter with a large amount of nutrients; Applied in small volumes with high nutrient value, but no effect as a bulky organic material on the soil; Organic is considered less damaging as it breaks down leaving natural residues in the soil where inorganic leave residue salts. Inorganic salts can build up (especially in containers).

INORGANIC NUTRIENT

Man-made (by chemical process, e.g., Haber process/often crystals/powders or prills); Often quick acting, as the nutrient is supplied in the form that the plant will take up and use straight away (ammonium nitrate 34% N).

Define what is meant by ‘fertilisers’.

FERTILISER Providing plants with direct sources of nutrients. A substance containing a high proportion of plant food or foods related to its volume (organic fertiliser applied by the gram/bulky organic matter low in foods applied by the barrow full). Fertilizers (or fertilisers) are substances that supply plant nutrients or amend soil fertility.

They are the most effective (30 -80 per cent increase in yields) means of increasing crop production and of improving the quality of food and fodder.

Fertilizers are used in order to supplement nutrient supply in the soil, especially to correct yield-limiting factors.

Fertilizers are applied to promote plant growth; the main nutrients present in fertilizer are nitrogen, phosphorus, and potassium (the ‘macronutrients’) and other nutrients (‘micronutrients’) are added in smaller amounts.

Fertilizers are usually directly applied to soil, and can also be sprayed on leaves as a foliar feeding.

Works immediately : In-organic fertilizers do not need a certain time to be broken down or decomposed before usage because these contain nutrients that can be readily absorbed by plants.

Contains all necessary nutrients that are ready to use: Inorganic fertilizers are designed to give plants all the nutrients, Nitrogen, Phosphorous and Potassium that they need in appropriate proportions and amounts

Leeching happens

Inorganic fertilizers contain nutrients that have been broken down already into the most basic of its components for easy absorption by the plants.

Yet, it can also be washed away easily when watering or irrigating the plants.

This is called leeching. Leeching happens very often as you water your plants.

Hence, a lot of the fertilizer goes to waste.

Nitrogen is one of the elements that easily get washed away since it usually settles below the roots of the plants quickly.

When you’re using inorganic fertilizers you need to pay special attention to the roots of the plant when you’re watering it and not over water the area so that you’re not encouraging the leeching of the nutrients in the soil.

Accumulation of toxic wastes

Inorganic fertilizers are not entirely composed of the nutrients needed by the plants. It also contains salts and other compounds.

These are not absorbed by the plants so they are left behind in the soil and build up over time.

When found in large amounts in the soils, these compounds can alter the chemistry of the soil that makes it less ideal for planting.

Over times, the soil needs to be neutralized using other substances to return it to a normal state that is suitable for planting

Too much is not a good thing

Fertilizers are good sources of nutrients for plants.

However, too much of it can also be harmful to the plants.

Applying the fertilizer directly to the plants may burn the delicate plant structures such as the roots.

This could affect the over-all development of the plant.

Inorganic fertilizers have both good and bad points.

Should you consider using them, better maximize and the advantages and try to prevent all its avoidable disadvantages.

State what is meant by EACH of the following terms applied to fertilisers: soluble and slow release, straight and compound, controlled release using ONE NAMED example for EACH fertiliser.

SOLUABLE FERTILISER Easily dissolved into water (soil water); Usually inorganic (becoming quickly available to the plant??); Sulphate of ammonia 21% N.

STRAIGHT FERTILISER These contain only one or mainly one nutrient. They are usually used to provide different nutrients at different times of the year, or to correct particular nutrient deficiencies. They are usually inorganic Fertilizers contain one food or one in a higher % than another; Sulphate of Ammonia 21% N; Hoof and Horn 14% N, 2% P.

COMPOUND FERTILISER These contain a mixture of different nutrients, and may be balanced (containing similar proportions of all the major plant nutrients) or may supply more of some nutrients than others, as per the requirements of different crops. They may be organic or inorganic, or contain both. A commercially produced mixture of fertilizers; Feeding differing ratio of N.P.K.; Can be as a powder (J.I. Base) or formed into a granular form Growmore; Easy to use; Differing products can be used to suit differing situations – Toprose/Top Lawn; Less chance of creating an imbalance in the soil; Compounds: Growmore 7, 7, 7% or 1-1-1; Blood, fish and bone 6, 7, 6 % (question the source of potash for true organic); Toprose 5, 6, 12; Top Lawn 10, 5, 3; John Innes Base 5-7, 5, 10.

SOLUABLE FERTILISER Easily dissolved into water (soil water); Usually inorganic (becoming quickly available to the plant??); Sulphate of ammonia 21% N.

CONTROLLED RELEASE FERTILISER

Controlled release fertilisers: These are almost always granules of inorganic fertilisers coated with a porous material such as sulphur or synthetic resin. Water enters the granule and the fertilisers leach out into the surrounding soil. The warmer the soil, the faster the leaching; this corresponds to plant growth which is faster in warm weather. By varying the thickness of the coating granules can be designed to feed plants for different periods of time.

A compound fertilizer granule encased in a skin that allows water to enter, dissolve some fertilizer and exit at a known rate (temperature related); “Osmacote” 4 month used in compost for bedding plants or hanging baskets; “Osmacote 12/14 month used in compost for container growing of shrubs.

Benefits: Removes the need to liquid feed plant after the effect of the base fertilizer has worn off when used as part of the base fertiliser as release is temperature controlled reduction in leaching.

As the feed is released at a controlled rate, the risk of root scorch is removed. If used in the production of bedding plants it gives them a good shelf life and boost when planted out.

Limitations: Considered expensive; Slow initial release of plant foods; You cannot so easily manipulate the plant’s reaction to differing feeds (growing fuchsias); If mixed in stored compost the release of nutrients can reach harmful levels; If weather is unseasonably warm, feeding can continue (Wimbledon tennis courts).

OSMACOTE Brand pf controlled release fertiliser

GROWMORE balanced fertilkiser 7-7-7

State what is meant by EACH of the following terms: base dressing, top dressing, liquid feed, foliar feed, using ONE NAMED situation to illustrate the use of each.

BASE DRESSING Base dressing: This is the incorporation of fertiliser into the soil or potting compost before sowing or planting. A fertilizer, usually a compound applied at the preparation stage; J.I. Base (plus lime) mixed into a mixture of loam, peat and sand to produce a potting compost; Growmore raked into the soil of a vegetable garden prior to sowing or planting.

JOHN INNES BASE base dressing:

BLOOD FISH AND BONE the source of potash for true organic

TOP DRESSING

This is the application of quick-acting fertilisers to the soil surface around plants to stimulate growth, and is usually carried out in spring at the start of the growing season. Take care to avoid leaf contact, which can cause scorching, and to protect against over application, which could cause root damage and pollution of ground water.

A fertilizer applied to a growing crop to keep it growing after the effect of the base feed has worn off; Can be a compound or straight; Easily applied, but may scorch the foliage of the plants; “Growmore” quick acting so repeated as a top dressing 6/8 weeks after applying as a base feed. Needs to be mixed into the soil by hoeing it in as not very soluble; Sulphate of ammonia applied to lawns spring and early summer to keep the grass green and growing. Very soluble, apply evenly before rain or water in (not applied after August).

LIQUID FEED Liquid fertilisers or soluble powders and granules can be dissolved or diluted and watered onto plant roots during the growing season to give them an instant boost. They are mainly used for feeding glasshouse crops, pot plants and bedding. The nutrients in liquid fertilisers are instantly available. Care must be taken to avoid leaf contact, which can cause scorching.

As top dressing; Applied as a liquid to a growing crop after the effect of the base has worn off, 6/8 weeks after potting; To keep the plant growing – mostly containers/pot plants/hanging baskets (but can be applied to lawns/flower beds, etc.); Easily dissolving, quick acting, give weekly; Must be applied to moist compost so as not to scorch the roots; Miracle Grow (high ratio of nitrogen); Tomato feed, Seaweed liquid Crystals/or liquid form; Measured out into a watering can and watered onto the pot (small scale) (or applied through a dilutor into the water supply/hose pipe); Growers can manipulate plant more easily using liquid feeds as it is possible to change from one product to another. Fuchsia growers can use high nitrogen to promote growth then change to high potash to promote flowers; Constant heavy feeding can result in a build-up of residue salt in the compost that might need flushing through.

SULPHATE OF AMONIA lawn topdressing

MIRACLE GRO

SEAWEED FEED

FOLIAR FEED This is the application of a dilute solution of fertiliser to the leaves of plants, useful as an emergency treatment for correcting nutrient deficiencies or for providing quick supplementary feeding. The absorption of liquid fertiliser is greatest where leaf surfaces are tender, particularly on the under surfaces of leaves or on young leaves that are just expanding. Foliar feeds should not be applied in bright sunlight because the foliage may be scorched.

Applied as a liquid, but direct to the leaves not the compost or soil. Leaves can absorb food direct through the foliage so bypassing the roots; Gives a very quick response; Good way of feeding if the roots are damaged such as newly planted bare root trees/shrubs/evergreens or just as a way of feeding (DOFF make a ready mixed tomato foliar feed – although expensive).

State the benefits and limitations of nutrient sources (environmental, health and safety issues, timing of application, variability of the material).

NUTRIENT SOURCE

The benefits and limitations of nutrient sources:

Environmental: Bulky organic; Good recycling of organic material; Runoff from heaps can pollute waterways; Fertilises; Issue of energy used in manufacture; Some quick acting materials can leach and pollute waterways (algae bloom); Salt residues can build up in soils or compost to toxic levels.

Health and Safety: All weight of handling; Bulky organic pathogen content? (hygiene); Allergy to contents possible Attracts dogs cats & foxes to the plants Bone meal unsterilized may carry CJD – all commercial types now sterilised Imported organic anthrax in unsterilized blood and bone meal

Timing of application: Bulky organic winter digging in; Spring – use as mulches; Fertilisers: Base – use in preparation stage; Top/liquid/foliar – apply to growing crop as required; Lawns – spring and summer, high nitrogen up to August; Spring cabbage – late March to give a boost to growth after the winter leaching of nutrients from the soil.

Variability of the material: Bulky organics nutrient content very variable; Organic fertilisers slightly variable; Inorganic fertiliser stable content.