Explanation:

Burning of wheat and rice straw has also contributed to loss of soil fertility apart from causing air,pollution. Punjab produces around 23 million tonnes of rice straw and 17 million tonnes of wheat straw, annually. This straw is rich in Nitrogen, Phosphorus and Potassium contents. However, instead of its recycling into the soil by mulching, it is burnt in the fields. This raises the temperature of the soil in the top 3 inches to such a high degree that Carbon: Nitrogen equilibrium in soil changes rapidly. The carbon as CO2 is lost to atmosphere, while nitrogen is converted to nitrate. This leads to a loss of about 0.824 million tonnes of NPK from soil. This is about 50 percent of total fertilizer consumption in the state.Considering that 90% of rice and 30% of wheat straw is available for recycling, it will be equivalent to recycling of 0.56 million tonnes of nutrients worth Rs. 4 billion. Moreover, agriculture experts also maintain that fire in the fields kills friendly pests and bacteria (which increase the fertility of soil).