Soil, that part of the earth's crust into which plants send their roots for food and water.
Stamen, that part of a flower which bears the pollen.
Stigma, the part of the pistil which receives the pollen.
Stomata, breathing pores in plants.
Subsoil, that part of the soil which lies beneath the soil that is worked with the tillage tools.
Sap root, a main root that runs straight down into the soil.
Tillage, stirring the soil.
Transpiration, the giving off of water from plants.
Tubercle, a small nodular growth on the roots of plants.
Under drainage, drainage from below.