What is the optimal $pH$ range for the growth of most plants?

Crop plants need various fertilizers for their growth. Their yield is limited by that fertilizer which is present in relatively minimum. The principle contained in this statement was enunciated by

Which of the following herbicides is derived from urea?

Humus is:

Which of the following pairs of soil types and their characteristics is $NOT$ correctly matched?

Deep black soil is considered to be highly productive due to high proportion of