Transcript envreq
Environmental Requirements Soil composed of sand, silt, and clay, organic matter, living organisms, and pore spaces Soil classified according to percentage of sand, silt, and clay they contain. Soil Improvement Drainage – change soil structure –add organic matter to encourage earth worms Drainage drainage tiles raise planting beds ditching between beds Perlite (soiless) Moisture retention adding organic matter (o.m.) sources of o.m. animal manure green manure Vermiculite (soiless) Sources of O.M. peat moss sawdust mulches - compost or wood chips Mulches placed on the surface to help retain moisture reduce runoff and evaporation reduce weeds Fertilizing fertilize results according to soil test Planting Media Mixes Soil less mixes advantages include : uniformity - doesn’t vary in pH, fertility or texture advantages sterile lightweight good moisture retention and drainage free of weed seeds disadvantages light weight - pots tip in strong wind minor elements are missing transplants may not adjust well to new media Content of mixes perlite improve aeration volcanic origin Vermiculite exploded Mica improves aeration Plant food and fertilizers divided into two groups Major elements (macro) Nitrogen - N Phosphorus - P Potassium - K minor elements (micro) Calcium - Ca Magnesium - mg Sulfur - S Iron - Fe minor elements (micro) Manganese Boron -B Copper - Cu Zinc - Zn - Mn Plant requirements large amounts of major elements relatively small amounts of minor elements Commercial fertilizers shows % or pounds per cwt. (100#) of the three major elements in large numbers on the container or bag. Commercial fertilizers 5-10-5 5% N, 10% P, 5% K remaining 80% is filler NP&K are always listed in that order. Soil tests determine amount of elements needed for various plants. Nitrogen generally purchased in one of four forms Nitrate of soda ammonium nitrate Nitrogen ammonium sulfate urea formaldehyde Nitrogen has most noticeable effect on plants encourages above ground vegetative growth regulates use of other elements Too much N lower disease resistance weaken stem because of long soft growth lower fruit quality Too much N delay maturity increase winter damage to plants Not enough N yellow or light green color stunted root and top growth N lost easily from soil leaching - being filtered down through soil with water not held by soil particles, dissolved in water O.M. holds insoluble N for slow release Don’t use excess N quickly lost through leaching can damage plants Phosphorous held tightly by soil particles not easily leached Phosphorous effects plants in several ways encourage cell division Phosphorous flowers and seeds don’t form without it hastens maturity, offsetting quick growth caused by N. Phosphorous encourage root growth makes K more available increase disease resistance improves quality of grain, root and fruit crops Phosphorous container plants can be damaged by excess P increases soluble salt content of medium causes dehydration of roots Phosphorous Insufficient P purple color on underside of leaf reduced flower fruit and seed production Insufficient P susceptibility to cold injury susceptibility to plant diseases poor quality fruit and seeds Potassium modifies both fast soft growth of N and early maturity of P is essential Potassium increase disease resistance encourages healthy root systems essential for starch formation Potassium development of chlorophyll efficient use of CO2 Insufficient K leaves appear dry and scorched with irregular yellow areas on the surface Lime CaCO3- Calcium Carbonate acts as a plant food affects soil acidity soil acidity affects availability of plant food elements Lime furnishes Calcium pH measure of acidity or alkalinity pH scale - runs from 0 - 14 most plants grow best from 5.6-7.0 pH 7.0 is neutral pH of 7 or above is alkaline or basic pH below 7 is acidic pH as numbers decrease, solution becomes more acidic. As numbers increase, solution becomes more basic or alkaline pH if soil is too acidic, lime is added to raise the pH if soil is too alkaline, sulfur is added Above ground environment temperature some plants prefer cool weather some plants prefer warm weather Temperature there are temperatures above and below which plants stop growth generally, plant growth rate increases as temps increase up to about 90 degrees Light must be present before plants can manufacture food plants vary in light requirement effects flowering Photoperiodism response to different periods of day and night in terms of growth and maturity Photoperiodism short day plants chrysanthemum and Christmas Cactus bloom when days are short and nights are long Photoperiodism long day plants lettuce and radishes bloom when days are long and nights are short Photoperiodism day length indifferent do not depend on length of light or darkness African Violet and tomato Phototropism plants appear to grow towards the sun or light source Humidity moisture level of the air most plants grow best in 4080% RH Relative Humidity Humidity too high humidity may cause the spread of fungus diseases Plant diseases and Insects reduce production lower fruit and vegetable quality Carbon Monoxide reduces plant growth can kill plants