12.7 FERTILIZERS

Fertilizers are substances that provide essential elements for plant growth. These elements are essential to enhance crop yields. Fertilizers mainly provide three main nutrients, nitrogen (N), phosphorus (P), and potassium (K), hence known as NPK fertilizers. Urea, potassium nitrate, and ammonium salts such as di-ammonium phosphate (superphosphate) are important fertilizers. Fertilizers dissolve in water. So they provide nutrients to the plants in a readily available form. It is important to give fertilizers at the right time and in the right amount. This practice is called nutrient management. It optimizes the intake of nutrients by plants and reduces the loss of nutrients. This practice can minimize environmental problems such as nutrient runoff into water bodies.

KEY POINTS

• Hepatitis a viral disease occasionally spreads through drinking polluted water.
• Unclean water supplies, poor sanitation and poor hygiene kill 2,668,000 people worldwide each year.
• Anhydrous copper (II) sulphate is used to detect water, on absorbing water it turns blue.
• Water from natural resources contains useful and harmful substances.
• Nitrates and phosphates present in water damage aquatic life.
• Sewage contains harmful microbes which cause diseases.
• Sedementation, filteration, and chlorination are major steps in the treatment of domestic water supply.
• Urea, ammonium salts, and nitrates are used as fertilizers.
• NPK fertilizers provide the elements nitrogen, phosphorous, and potassium for plant growth.

References for additional information

• Chemistry Kelter, Carr, Scott.
• Environmental Chemistry, Barid, Colin.
• Environmental Science, Richard Wright, R.T. Wright