PESTICIDE - Any substance which alone, in chemical combination, or in any formulation with one or more substances is defined as a pesticide in section 2(u) of the Federal Insecticide, Fungicide, and Rodenticide Act (7 U.S.C. 136(u) et seq).
PLANTING STOCK - Any plant or plant tissue other than annual seedlings but including rhizomes, shoots, leaf or stem cuttings, roots, or tubers, used in plant production or propagation.
PLOW PAN - Compacted layer immediately below the depth of regular tillage. Moldboard plows, disks, and rotary tillers are notorious for creating plow pans.
POINT - The leading edge of a stiff tine. The shape of a point impacts its ability to penetrate and how much lifting and soil disturbance it causes. The front of a plow share is also called a point.
POLYCULTURE - A field (or cropping system) with multiple, interacting crops, or pertaining to such a field or cropping system.
PRIMARY TILLAGE - Tillage used to break or fracture soil for a depth of six or more inches. Primary tillage implements vary in their ability to penetrate high-strength soils and cut through plant residues. Examples include moldboard plows, heavy disks, spading machines, heavy rotary tillers, chisel plows, and subsoilers.
PTO-POWERED TILLAGE - In contrast with draft powered tillage implements, such as the moldboard plow, and ground driven rotary tillage, such as the rotary hoe, PTO-powered tillage implements have a greater capacity to pulverize and mix soil structure in one pass because they receive rotary power from a tractor. Rotary tillers, spading machines, rotary harrows, and reciprocating harrows are examples of PTO-powered tillage.
PUDDLING - Tillage designed to disrupt aggregates and disperse clay, creating an impermeable layer that will perch water. Puddling is a tillage objective in flooded rice systems, but is undesirable in other production systems.