What does nitrogenous fertilizers contains ?

Abiotic factors includes ____________________.

Which of the following are Kharif crop ?

Which of the following crop are grown in two year rotation ?

Which of the following points should be considered while making selection of crops for crop rotation?

What are the disadvantages of fertilizers ?

Which of the following are correct :

(a) Weeds also reduce crop productivity by competing with the main crop for nutrients and light.

(b) Continuous cultivation, bush burning and inability to control erosion can lead to lower crop agricultural output.

Which of the following are correct :

(a) Biotic factors are the diseases, insects and nematodes while abiotic factors are the drought, salinity, water logging, heat, cold and frost which affect the crop productivity.

(b) Abiotic factors are the diseases, insects and nematodes while abiotic factors are the drought, salinity, water logging, heat, cold and frost which affect the crop productivity.

Which of the following are correct :

(a) Crops require suitable climatic conditions for their proper growth and flowering.

(b) Crops do not require particular durations of daylight for their proper growth and flowering.

Which of the following are correct :

(a) Many forms of aquatic life including fish may die as a result of water pollution.

(b) The excessive use of chemical fertilizers can change the nature of the soil making it too alkaline.

(c) The excessive use of chemical fertilizers can change the nature of the soil making it too acidic.