Environmental Requirements Soil wcomposed of sand silt and

Environmental Requirements

Soil wcomposed of sand, silt, and clay, organic matter, living organisms, and pore spaces

Soil wclassified according to percentage of sand, silt, and clay they contain.

Soil Particles wvary greatly in size wsand is the largest wsilt - medium wclay - smallest

Clay wparticles hold moisture and plant food elements more effectively than larger particles.

Soil Profile wconsists of 3 basic layers wtopsoil wsubsoil wsoil bedrock

Topsoil wrepresents depth normally plowed

Subsoil wdeep rooting plants send roots down into subsoil

Sandy Soil wsilt and clay make up less than 20% by weight wdrain well wlittle water holding capacity

Clayey Soil wmust contain at least 30% clay wholds more moisture than is good for plants wpoor drainage

Loamy Soil wmost desirable soil wequal parts sand, silt and clay

Soil Improvement w. Drainage – change soil structure – add organic matter to encourage earth worms

Worms wtheir tunnels and castings result in better soil structure aggregation - clinging together

Drainage wdrainage tiles wraise planting beds wditching between beds

Moisture retention wadding organic matter (o. m. ) wsources of o. m. wanimal manure wgreen manure - crop grown and plowed under to improve the soil

Sources of O. M. wpeat moss wsawdust wmulches - compost or wood chips

Mulches wplaced on the surface to help retain moisture wreduce runoff and evaporation wreduce weeds

Moisture retention wirrigation

Fertilizing wfertilize according to soil test results

Diseases wplant resistant varieties wchemicals wsoil pasteurization – heat to 180 degrees F for 30 minutes.

Nutritional deficiencies wshow on leaves of plants w. Nitrogen - pale green leaves w. Phosphorus - purple color on underside of leaves

Planting Media Mixes w. Soil less mixes wadvantages include : uniformity - doesn’t vary in p. H, fertility or texture

advantages wsterile wlightweight wgood moisture retention and drainage wfree of weed seeds

disadvantages wlight weight - pots tip in strong wind wminor elements are missing wtransplants may not adjust well to new media

Content of mixes wperlite wimprove aeration wvolcanic origin

Vermiculite wexploded Mica wimproves aeration

Plant food and fertilizers wdivided into two groups w. Major elements (macro) w. Nitrogen - N w. Phosphorus - P w. Potassium - K

minor elements (micro) w. Calcium - Ca w. Magnesium - mg w. Sulfur - S w. Iron - Fe

minor elements (micro) w. Manganese - Mn w. Boron - B w. Copper - Cu w. Zinc - Zn

Plant requirements wlarge amounts of major elements wrelatively small amounts of minor elements

Commercial fertilizers wshows % or pounds per cwt. (100#) of the three major elements in large numbers on the container or bag.

Commercial fertilizers w 5 -10 -5 w 5% N, 10% P, 5% K wremaining 80% is filler w. NP&K are always listed in that order.

Soil tests wdetermine amount of elements needed for various plants.

Nitrogen wgenerally purchased in one of four forms w. Nitrate of soda wammonium nitrate

Nitrogen wammonium sulfate wurea formaldehyde

Nitrogen whas most noticeable effect on plants wencourages above ground vegetative growth wregulates use of other elements

Too much N wlower disease resistance wweaken stem because of long soft growth wlower fruit quality

Too much N wdelay maturity wincrease winter damage to plants

Not enough N wyellow or light green color wstunted root and top growth

N lost easily from soil wleaching - being filtered down through soil with water wnot held by soil particles, dissolved in water w. O. M. holds insoluble N for slow release

Don’t use excess N wquickly lost through leaching wcan damage plants Too much N!

Phosphorous wheld tightly by soil particles wnot easily leached

Phosphorous weffects plants in several ways wencourage cell division

Phosphorous wflowers and seeds don’t form without it whastens maturity, offsetting quick growth caused by N.

Phosphorous wencourage root growth wmakes K more available wincrease disease resistance wimproves quality of grain, root and fruit crops

Phosphorous wcontainer plants can be damaged by excess P wincreases soluble salt content of medium wcauses dehydration of roots

Phosphorous w. Insufficient P wpurple color on underside of leaf wreduced flower fruit and seed production

Insufficient P wsusceptibility to cold injury wsusceptibility to plant diseases wpoor quality fruit and seeds

Potassium wmodifies both fast soft growth of N and early maturity of P wis essential

Potassium wincrease disease resistance wencourages healthy root systems wessential for starch formation

Potassium wdevelopment of chlorophyll wefficient use of CO 2

Insufficient K wleaves appear dry and scorched with irregular yellow areas on the surface

Lime w. Ca. CO 3 - Calcium Carbonate wacts as a plant food waffects soil acidity wsoil acidity affects availability of plant food elements

Lime wfurnishes Calcium

p. H wmeasure of acidity or alkalinity wp. H scale - runs from 0 - 14 wmost plants grow best from 5. 67. 0

p. H w 7. 0 is neutral wp. H of 7 or above is alkaline or basic wp. H below 7 is acidic

p. H was numbers decrease, solution becomes more acidic. w. As numbers increase, solution becomes more basic or alkaline

p. H wif soil is too acidic, lime is added to raise the p. H wif soil is too alkaline, sulfur is added

Above ground environment wtemperature wsome plants prefer cool weather wsome plants prefer warm weather

Temperature wthere are temperatures above and below which plants stop growth wgenerally, plant growth rate increases as temps increase up to about 90 degrees

Light wmust be present before plants can manufacture food wplants vary in light requirement weffects flowering

Photoperiodism wresponse to different periods of day and night in terms of growth and maturity

Photoperiodism wshort day plants wchrysanthemum and Christmas Cactus wbloom when days are short and nights are long

Photoperiodism wlong day plants wlettuce and radishes wbloom when days are long and nights are short

Photoperiodism wday length indifferent wdo not depend on length of light or darkness w. African Violet and tomato

Phototropism wplants appear to grow towards the sun or light source

Humidity wmoisture level of the air wmost plants grow best in 4080% RH w. Relative Humidity

Humidity wtoo high humidity may cause the spread of fungus diseases

Plant diseases and Insects wreduce production wlower fruit and vegetable quality

Gases and Air Particles w. CO 2 is vital to plants for Ps w. Air pollutants can cause damage

Air Pollutants w. Sulfur Dioxide - SO 2 - from burning coal w. Carbon Monoxide - CO exhaust from cars

Carbon Monoxide wreduces plant growth wcan kill plants