How do biotic and abiotic factors adversely effect crop production ?

. Biotic factors are living organisms that reduce

crop productivity due to either directly feeding

on them (e.g., insects, rodents) or causing

diseases (e.g., nematodes, mycoplasmas,

bacteria, viruses, fungi).

Abiotic factors are non-living components of

environment that effect growth of crop plants

like excess of water (water-logging), scarcity

of water drought, salinity, heat, cold or frost.

Water logging reduces aeration of soil which

is harmful to growth and functioning of roots.

In drought, water is not available to meet the

requirement of the plants for transpiration,

growth and photosynthesis. Frost, cold and

heat reduce or inhibit metabolic activities and

are, therefore, harmful.