require a number of attributes to enable them to grow, whilst carbon, oxygen
and hydrogen can be obtained from the air and water. Due to soil quality
some plants require fertilisers which have the additional elements that
enable the plant to flurish. Click
here to view a chart on optimum
pH levels for crops.
Nitrogen is an essential part of the proteins in plant cells. It is most important for leaf growth and is a necessary part of the green pigment chlorophyll.
Phosphorous is important in cell formation so is most needed by growing parts of the plant. Phosphorous promotes the developemnt of seedlings, root growth, flowering and formation of fruits and seeds.
Phosphorous is notoriously deficient in Australian soils and most plants have evolved to handle low levels of phosphorous. Phosphorous-rich fertilisers should always be used sparingly around native, especially those in the Proteaceae family.
Potassium assists in photosynthesis and is helpful to the plant's 'food factory'. It assists the plant's overall strength, water uptake and disease resistance, and improves the quality of flowers, fruits and seeds.
Calcium forms the cell wall structure. It is available in lime, superphosphate and gypsum but is quickly leached out by heavy rain.
Sulphur forms part of plant protein. Defiency is relatively rare because sulphur is found in most plant foods.
Magnesium is important in photosynthesis because it is present in chlorophyll. New leaves have first call on this nutrient and, because magnesium moves very readily through the plant's system, deficiency is most often evident as yellowing of the older leaves. Magnesium is supplied by an application of Epsom Salts dissolved in water.
Trace elements generally function as essential parts of enzymes in the cell. Many important enzymes consist of proteins which attach to co-enzymes, generally made up of trace elements. The control of proteins and other cell processes through chemical reactions is done by enzymes.
Iron allows plants to produce chlorophyll and to activate several enzymes especially those involved in oxidation / reduction processes of photosynthesis and respiration.
Manganese Manganese is essential as an enzyme activator which helps with nitrate assimilation. It is also primarily involved in photosynthesis and chlorophyll production.
Zinc forms part of an enzyme which produces carbon dioxide and maintains CO2 levels for photosynthesis. ZINC also plays a role in hormone production. Poor mobility of ZINC generally leads to deficiency problems.
Copper is an activator of several enzymes in plants, and plays a key role in Vitamin A production.
Boron is needed for sugar movement within the plant, as well as formation of new cells at growing points. Boron also effects pollination and seed development.
Molybdenum is an essential part of some plant enzymes - it is necessary for plants to make use of nitrogen and also essential in legumes for nitrogen fixation to occur.
Page Updated 10th August 2001