Photic zone

ing triple superphosphate (NPK 0-45-0), superphosphate (NPK 0-20-0), and rock phosphate (NPK 0-25-0). It may be applied in natural forms such as cottonseed meal, blood meal, bonemeal, banana peels, etc.

photic zone The area of a water body pierced by sunlight.

photoelectric cell A device in an electrical circuit or incorporated into a luminaire (light fixture) that opens or closes the circuit (turns on or off electricity and/or light) as the device is affected by light striking a special portion of its surface. It is used most often to direct lights to automatically turn on at dark and off at morning light.

photoelectric control An electrical control or switch that is actuated by light or a lack of it.

photometer Any instrument capable of measuring luminance, luminous intensity, luminous flux, illumination, etc.

photometry The measurement of light.

photopair Overlapping aerial photographs that may be utilized in stereoscopic interpretation to determine such information as elevations and contours, heights of vegetation or structures, etc.

photoperiod A recurring cycle of light and dark periods of consistent length.

photoperoidism In horticulture, a reference to the alternating periods of lightness and darkness as they affect the growth of plants.

photosynthate A product of photosynthesis.

photosynthesis The process in planting of making organic matter from inorganic matter within their tissues containing chlorophyll when there is sunlight.

phototaxis An orientational reflex stimulated by light.

phototropic In plant material, a tendency to grow away from light (negatively phototropic) or toward it (positively phototropic). Stems and shoots are positively phototropic, and roots are negatively phototropic.

phototropism The response of plants to light. See also phototropic.

photovoltaic Creating electricity from solar energy.

phreatophyte A deep-rooting plant that typically extracts its water from the water table or an area of soil just above it or a plant that usually has a major part of its root system in soil permanently saturated with water, usually below ground level. Examples are cottonwoods and willows.

phylloclade In botanical terms, a flattened branch functioning as foliage, or a part of the stem having the general form and function of a leaf.

phyllode In botanical terms, a flat expanded petiole with the form and functions of a leaf, or a more or less expanded, bladeless petiole.

phyllome Part of a leaf or derived from a leaf.

phyllopodic A botanical term meaning that the lowest leaves are well developed.

phyllotaxus or phyllotaxy A botanical term referring to the leaf arrangement on a stem.

phylogeny The evolutionary history of a plant group.

phylum A group or family that shows unity in descent. (The broadest class in plant kingdom taxon is a division; the broadest class in animals is the phylum.)

physiography The physical, mainly natural, character of a site or region.

Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

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