NITRIGEN PRODUCTS

Urea

Features and Benefits:

• Urea is an organic compound that occurs naturally. Synthetic Urea is the most widely used nitrogen fertiliser in the world.
• The wide acceptance of Urea is due to its agronomic acceptability and its low relative cost. Granular Urea is tailored for easy handling, even spreading and blending.

Uses:

Plants take up nitrogen from the soil in the mineral forms of nitrogen, both ammonium and nitrate before converting it to plant protein nitrogen. Plants vary in their preference to utilise either form of nitrogen. Nitrate is considered the main source because it is mobile in the soil. On addition to the soil, Urea dissolves into the soil solution and is converted to ammonium and then to nitrate.

Conversion is favoured by:

• Temperature – the activity range is wide, varying from -20°C to 37°C with the optimum >20°C.
• Organic matter – activity is enhanced in soils high in organic matter which favours microbial activity.
• The time for Urea to be converted to ammonium will depend on the conditions of moisture and temperature. The reaction will begin to occur 24 hours after application and be complete within 2 to 5 days. The reaction time is slowest in cold, waterlogged conditions.

It is these biological processes in the release of nitrogen from Urea to plants that gives Urea its main characteristic of a slower release form of nitrogen. Urea has longer availability for uptake by plants and release rates that are more closely related to plant growth.

Sulphate of Ammonia (S.O.A)

Features and benefits:

• Sulphate of ammonia is commonly used as a source of nitrogen and sulphur.
• It is commonly blended with other fertilisers to supply sulphur.
• Higher nitrogen cost can be one of the main factors limiting the use of SOA, however, if the value of the available sulphate sulphur is considered it can be good value.
• Where conditions exist that nitrogen losses through volatilisation of Urea occur  SOA can be used more efficiently as its nitrogen is in the ammonium form.

Uses:

SOA is a valuable fertiliser as a straight product or in blends.
Sulphur in SOA is sulphate sulphur which is the form taken up directly by plants. Sulphate sulphur is readily soluble in water and goes straight into solution when applied to the soil (providing there is moisture).

SOA releases nitrogen to the soil directly as ammonium NH4+, which is converted by bacteria to nitrate nitrogen. This process is favoured by conditions conducive to microbial activity, such as warm temperatures, moisture and organic matter. The rate of this reaction depends on those conditions and complete nitrification of applied ammonium can vary from a few days to several weeks.

PHOSPHORUS PRODUCTS

Diammonium Phosphate (D.A.P)

Features and Benefits:

• High analysis source of phosphorus.
• N:P ratio of 1:1 makes it an effective source of nitrogen.
• DAP releases free ammonium. Nitrogen in the ammonium form resists leaching and is a slower release form of nitrogen.
• The free ammonium gives a higher pH reaction immediately around the granule.
• The low cost of nitrogen in DAP makes it a cost effective source of nitrogen if Phosphorus is also required.

Uses:

One of the major cropping fertilisers used in Australia as a source of both phosphorus and nitrogen. The high phosphorus content makes it a true high analysis fertiliser. DAP and DAP blends are used on a range of crops in broad-acre farming, cereals, sugar cane, sowing pastures, dairy pastures, fodder crops and also in horticultural crops; for example, vegetables and tree crops.

Single Super Phospate (Super)

Features and Benefits:

• SSP is one of the cheapest forms of phosphate
• Supplies sulphate sulphur and calcium.
• The ratio of phosphorus and sulphur suits many crop and pasture needs.
• Both the phosphorus and sulphur are in readily available forms.
• Can be blended with other fertiliser products (except Urea & DAP)
• Can be stored easily for long periods, without taking up moisture.
• Contains calcium and sulphur (mostly as gypsum) and helps keep soil in good shape by maintaining soil structure.
• SSP provides a balance of P, S and Ca that mimics pasture growth requirements and is the best balanced P, S and Ca fertiliser for Australian pastures.

Uses:

The product is a low cost source of phosphorus and sulphur in a wide range of pasture  situations. SSP is a traditional product for supplying phosphorus and sulphur to pastures, the main two nutrients required for pasture production. Generally mixed with Sulphate of Ammonia and Muriate of Potash, but can be blended with other fertilisers.

POTASSIUM PRODUCTS

Muriate of Potash (M.O.P)

Features and Benefits:

• Potassium stimulates the growth of strong stems and gives the plant some disease resistance by promoting thickness of the outer cell walls.
• Adequate potassium can reduce moisture loss from growing plants, thereby giving some drought resistance.
• Potassium improves colour, flavour and storing quality of fruit and vegetables.
• MOP is the most concentrated form of granular potassium and typically the most cost effective.
• The even granule size of MOP allows for accurate spreading.
• MOP is commonly blended with SSP to supply major nutrients for pasture based systems

Uses:

MOP is used extensively for fertilising pastures, sugar cane, fruit trees, vegetables, and other field crops.

Sulphate of Potash (S.O.P)

Features and Benefits:

• SOP provides both potassium and sulphur in soluble forms.
• SOP contains no chloride and hence has a much lower salt index than MOP. Where soils are saline or sodic and where irrigation water may have high chloride levels SOP is the preferred form of potassium to use.
• Where seeds or transplants are placed in direct contact with fertiliser, SOP is much less likely to cause root burn of plants.
• Potassium stimulates the growth of strong stems and gives the plant some disease resistance by promoting thickness of the outer cell walls. Adequate potassium can reduce moisture loss from growing plants, thereby giving some drought resistance. Potassium improves colour, flavour and storing quality of fruit and vegetables.

Uses:

Potassium sulphate (SOP) can be a more expensive source of potassium than MOP and so its uses are often restricted to five main areas.

• Where soil or irrigation water salt levels are high and MOP is undesirable.
• Where chloride sensitive crops are being grown; for example, berries and vines.
• Where high chloride levels occur in irrigation water.