Power Harrow - A type of Harrow consisting of a number of p.t.o. driven transverse bars bearing Tines which reciprocate in a rotary manner. Used mainly to produce a fine tilth in a single opertion, particularly for potatoes.

Pre-emergence Herbicide - A herbicide applied following the sowing of a crop but before it emerges from the ground either before or after the weeds emerge.

Pregnancy - Condition of having a developing embryo in the body; the state of being with child.

Prepotent - A term used in breeding for a parent which has the ability
to transmit more characteristics to its offspring than the other parent.

Pressed Honey - Honey obtained by pressing brood less honeycombs with or without the application of moderte heat.

Prilled Fertilizer - A fertilizer in the form of small spherical granules,
about 2-3 mm in diameter.

Production Ration - Food supplied to an animal in excess of a Maintenance Ration so that it is able to gain weight, produce milk, etc.

Progeny Testing - The evaluation of the progeny of the progeny of an animal (e.g., in milk production) or plant variety, used to provide a guide for its breeding value.

Progesterone - A hormone secreted by the ovaries of mammals which stimulates the uterus to prepare for pregnancy and to nourish the developing embryo. With Oestrogen it controls the development of the Mammary Glands.

Propagation - The reproduction of a species. The term is used in horticulture to mean the artificial multiplication of plants by 'vegetative means, including the taking of cuttings, Layering, Budding, and grafting etc.

Protectants - Materials applied to the seed to protect it from soil fungi. certain organic mercury compounds like ethyl mercury ptoluene sulphamide, methyl mercury dicyan diamide, hydroxy mercuric chlorophenol etc. are highly effective protectants. Another group of fungicides, which are nonmercuric organic compounds like chloranil, thiram, ferbam, captan, zinc trichlorophenate etc. are less hazardous for operator and for the seed, but are somewhat less effective.

Protein - A class of complex organic compounds, containing Carbon, Oxygen, Nitrogen (about 16%), Hydrogen, and some also containing Phosphorus and Sulphur. They consist of thousands of Amino Acids linked in polypeptide chains and sometimes folded in a complicated manner. About 21 different amino acids are found in proteins, the sequence pf their arrangement in the chains being specific for each protein and giving it its characteristic properties. Proteins may be simnple, containing only amino acids, or conjugated, being combined with other compounds e.g., Carbohydrates (muco or glycoproteins), Fats (lipoproteins), nucleoproteins (phosphorus containing proteins combined with DNA and forming the Chromosomes of cell nuclei) etc.

With water they form the basic constituents of Protoplasm, and play an important role in the structure of organisms. Plant proteins are often stored in seeds and other organs and include globulins, albumins, gluteins and prolamins. They are digested by animals into their component amino acids which are then used to synthesise animal proteins. Examples include Albumen in eggs, osein in bones, Collagen n in connective tissue., Casein in milk globin in Haemoglobin, creatine in muscle, etc. Protein may be provided to livestock in feedingstuffs or animal origin (e.g., Fish Meal, Meat And Bone Meal, etc.), or of vegetable origin (e.g., oilseed Cake! peas, beans, etc.), although the latter tend to be deficient in one or two 'essential' amino acids. Enzymes are also proteins.

Protein Efficiency- Ratio (PER) - It is defined as the weight gain of rate per unit intake of protein and may be calculated from the following formula
PER=grain in body weight (g) Protein in take (g)
The PER value will vary with different protein sources as the composition of protein varies with regad to essential amino acids.

Protein Equivalent - An indication of the value of a feedingstuff expressed as the percentage of True Protein plus half the percentage of non protein nitrogen, on the assumption that the latter is capable of conversion to protein by animal.

Provender - Dry food for livestock such as hay and corn. Particularly
applied to cut straw or hay mixed with Meal.

Pulse Crops - Leguminous crop such as Peas and Beans yielding
edible seeds, (pulse).

Pund - A sheep Fold.

Pupa - A resting stage in insect Metamorphosis between the Larva and
young adult, during which movement and feeding ceases and a great change in form occurs. Also called chrysalis.

Pure Live Seed (PLS) - Percentage of pure germinating seed determined by multiplying pure seed percentage by its own germination percentage and dividing the product hundred.

Pure Seed - Seed true to its kind of variety.

Pykel - A hay ck.

Pyrethrins - Insecticidal compounds present in the flowers of the pyrethrum plant. The general term includes four compounds that occur together in the flowers, namely pyrethin I, pyrethin II, cinerin I, and cinerin II. The Pyrethrins are effective and quick acting against many insects and have very little toxicity warm blooded animals.

Pyrethrum - A genus of composite plants, the  powdered flowerheads
of which are used as an insecticide. Now less commonly used due to the introduction of synthetically produced insecticides.

Pyrophyllite - Mineral extensively used as a carrier or dilutent for insecticide and fungicide dusts. It is so named because its plate or leaflike structure (phyllon) will separated when heated (pyro). The mineral is ground to such finess that 85 per cent will pass through a 325 mesh screen. The particles have a flat or platelike structure, so they adhere quickly to plant surfaces dusted with them. The mineral looks, feels and acts like talc. But it is chemically inert or neutral to most materials used as insecticides and fungicides. It does not absorb moisture from the air.