Which of the following is not true about soil?
P. Soil not only supplies minerals but also harbours nitrogen fixing bacteria and other microbes
Q. It holds water
R. It supplies air to the roots
S. It acts as a matrix that stabilises the plant
T. It is a source of photosynthate
U. It is positively geotropic without any exception

1. S, T and U
2. T and U
3. S and U
4. R and T

Which of the following micronutrients does not form components of fertiliser?

Which of the following macronutrients does not form components of fertiliser?

Nitrogen:
Find the incorrect one.
1. Plants compete with microbes for it.
2. It is a limiting nutrient for both natural and agricultural ecosystem
3. Nitrogen has triple covalent bonds
4. Nitrogen fixation is conversion of nitrogen into nitrate

In nature, ……….. and ……….. provide enough energy to convert Nitrogen to nitrogen oxides (NO, NO₂, N₂O).

Decomposition of organic nitrogen of dead plants and animals into ammonia is called

Electrical nitrogen fixation leads to

Ammonia is first oxidized to nitrite by the bacteria except

Nitrification does not include

The nitrifying bacteria are