From Agricultural Testing
Fertilizers are chemical compounds applied to promote plant and fruit growth. They are usually applied either through the soil (for uptake by plant roots) or by foliar feeding (for uptake through leaves).
Fertilizers can be placed into the categories of organic fertilizers (composed of decayed plant/animal matter), inorganic fertilizers (composed of simple chemicals and minerals) and organo-chemical fertilizers where N, P, K can be added according to Fertilizer Act B.E. 2518 as amended by (No.2) B.E. 2550.
- Organic fertilizers are “naturally” occurring compounds, such as peat (plant material partly decomposed by the action of water) manufactured through natural processes such as composting, or naturally occurring mineral deposits.
- Inorganic fertilizers are manufactured through chemical processes (such as the Haber Process), also using naturally occurring
- Organo-chemical fertilizers are manufactured through the natural process by then inorganic fertilizers are added according to the Fertilizer Act B.E.2518 as amended by (No.2) B.E. 2550.
When properly applied, organic fertilizers can improve the health and productivity of soil and plants as they provide different essential nutrients to encourage plant growth. Organic nutrients increase the abundance of soil organisms by providing organic matter and micronutrients for organisms such as fungal mycorrhiza, which aid plants in absorbing nutrients. Chemical fertilizers may have long-term adverse impact on the organisms living in the soil and a detrimental long term effect on soil productivity.
Fertilizers typically provide, in varying proportions,
- the three major plant nutrients: nitrogen, phosphorus, potassium (known as N-P-K);
- the secondary plant nutrients: calcium, sulfur, magnesium
- and sometimes trace elements : boron, chloride, manganese, iron, zinc, copper, molybdenum
- and sometimes selenium with a role in plant or animal nutrition.