There are certain problems associated with the use of fertilizers related to right combination, right dosage and application at right time. Due to the lack of awareness, most of the farmers go for wrong application of fertilizers without proper combination and wrong dosages.
The excessive use of fertilizers adversely affect the nutrient balance of soils. It results in the depletion of soil fertility. The nitrogen in nitrogenous fertilizers may get stagnated in the soil or get volatalised as ammonia. It may escape into atmosphere increasing its nitrogen content. The nitrogenoxide may cause the depletion of ozone layer. The run off nitrogen from nitrogenous fertilizers into rivers and canals increases nitrate levels in water. It is harmful to animal and human beings.
The nitrate content in drinking water should not exceed 10 to 12 mg per litre. The nitrite, converted form nitrate, is poisonous and prevents the transportation of oxygen in blood and may also cause the death of infants. Cadmium will present in small quantities in phosphatic fertilizers. The continuous use of these fertilizers may increase cadmium level both in soil and crops. If it enters the food chain, it may cause health hazards like renal damage, anaemia, hypertension and liver damage.
To avoid problems, now more attention is focused on the increased use of organic manure. There is a great scope for the use of cattle dung, alternative fuels, manufacture of compost from urban wastes, forest litter and other wastes. The use of chemical fertilizers should be supplemented by extensive use of organic manure, green manures, crop residue, human and industrial wastes , composts and bio-fertilizers.
People should try to avoid chemical fertilizers as much as possible because of the above reasons. It is very good to practice or use the organic fertilizer with maximum avoidation of use of chemical fertilizers.