ENVIRONMENTAL EFFECTS OF USING FERTILIZERS

1. WATER :

Agricultural run-off is a major contributor to the EUTROPHICATION of fresh water bodies. The main contributor to eutrophication is phosphate, which is normally a limiting nutrient; high concentrations promote the growth of cyanobacteria and algae, the demise of which consumes oxygen. Cyanobacteria blooms ('algal blooms') can also produce harmful toxins that can accumulate in the food chain, and can be harmful to humans.

The nitrogen-rich compounds found in fertilizer runoff are the primary cause of serious oxygen depletion in many parts of oceans, especially in coastal zones, lakes and rivers. The resulting lack of dissolved oxygen greatly reduces the ability of these areas to sustain oceanic fauna.The number of oceanic dead zones near inhabited coastlines are increasing.

2. NITRATE POLLUTION :

Only a fraction of the nitrogen-based fertilizers is converted to produce and other plant matter. The remainder accumulates in the soil or lost as run-off. High application rates of nitrogen-containing fertilizers combined with the high water solubility of nitrate leads to increased runoff into surface water as well as leaching into groundwater, thereby causing GROUNDWATER POLLUTION.The excessive use of nitrogen-containing fertilizers (be they synthetic or natural) is particularly damaging, as much of the nitrogen that is not taken up by plants is transformed into nitrate which is easily leached.

3.CONTRIBUTION TO CLIMATIC CHANGE :

The greenhouse gases like carbon dioxide, methane and nitrous oxide are produced during the manufacture of nitrogen fertilizer. The effects can be combined into an equivalent amount of carbon dioxide. The amount varies according to the efficiency of the process. Nitrogen fertilizer can be converted by soil bacteria to nitrous oxide, a greenhouse gas. Thus giving rise to GLOBAL WARMING. 

4. SOIL IS AFFECTED BY :

Acidification, CHANGE IN SOIL BIOLOGY, accumulation of toxic elements like cadmium, fluoride, radioactive elements etc.