This layer consists of plant residue atop the soil surface. on a forest floor, it may be leaves and twigs. in a field, it may be crop residue left after harvest. a) this layer forms the base geologic material in a particular location; it is sometimes called bedrock. b) this layer loses minerals and organic matter to the layer beneath it. c) this layer accumulates minerals and organic matter leached from upper soil layers. d) this layer consists of organic matter, humus, and inorganic minerals. e) it facilitates plant rooting, has high nutrient content, and holds water.