Application of organic materials with C : N ratio wider than 20 to 30 : 1 leads to . . . . . . . . of soil N

Answer: Option D

The ideal carbon: nitrogen ratio generally should be around 30 : 1.
A C : N ratio of 20 : 1 leads to net nitrogen mobilization, and it causes a very fast decomposition process resulting in ammonia and soil carbon losses.
Thus the application of organic materials with a C : N ratio wider than 20 to 30 : 1 leads to the Immobilization of soil Nitrogen.