[" (c) " plant nutrition elements are classified as major or minor "],[" In planding on "],[" dependuailability in the soil "],[" (a) Their relative production in the ash obtained after "],[" fot their relative production in the ash obtained after "],[" b) burning the plants required by the plants "],[" (t) The relative importance in plant growth "],[" (d) Their relative importance in plant growth "],[" (d) Their relative importance in plant growth "]