Determining Plant Nutrients, Fertility and the Influence of Temperature on Plants.

Determining Plant Nutrients, Fertility and the Influence of

Temperature on Plants.

Identify the essential nutrients for plant growth.

• Nutrients – are substances that are essential for growth and production.

• There are 16 nutrients that are required by growing plants.

Identify the essential nutrients for plant growth

• Nutrients are supplied to the plant from the air while others are found in the soil

• Elements that are obtained from the air and water vapor by way of stomata include CARBON, HYDROGEN, AND OXYGEN.


• Stomata- are tiny pores on the underside of plants leaves that aid the plant in nutrient uptake and cooling process.

• Nitrogen, phosphorus, potassium, calcium, sulfur, and magnesium are supplied by the soil.

• Plants absorb these nutrients using roots to pull in nutrients that have been dissolved in water.


• Mnemonics –is the art of improving the memory using a formula

• A mnemonics has been developed to aid in recalling all sixteen elements.


• C. B. HOPKiNS CaFé Mighty good Closed Monday Morning See You Zen.

• Carbon (C) Boron (B) Hydrogen(H) Oxygen(O) Phosphorus (P) Potassium(K) Nitrogen(N) Sulfur(S) Calcium (Ca) Iron(Fe) Magnesium (Mg) Chlorine (Cl) Manganese (Mn) Molybdenum (Mo) Copper (Cu) Zinc (Zn)

Distinguish between micronutrients and macronutrients

• Plants nutrients are classified in two major categories.

• 1. Mineral or non-mineral nutrients

A. Four of the 16 essential nutrients are non- minerals. The 4 are

CARBON, HYDROGEN, OXYGEN and NITROGEN are all non-mineral nutrients.


• B. Mineral nutrients include: boron, phosphorus, potassium, sulfur, calcium, iron, magnesium, chlorine, manganese, molybdenum, copper, and zinc.


• 2. Macronutrients and micronutrients

• Macronutrients are needed in large quantities by plants.

• Nitrogen, Phosphorus, Potassium are the three primary Macronutrients. These nutrients are the main components of fertilizers.


• Calcium, Magnesium, and Sulfur are secondary macronutrients

• Nutrients that are needed by plants in small quantities are called micronutrients. They are the remaining 10 nutrients

Discuss the nitrogen cycle and its affect on plant nutrition.

• Nitrogen is a major requirement for plants to grow rapidly and maintain a healthy green color.

• The atmosphere is 78% nitrogen gas, it is the most common nutrients deficiency seen in plants.

• Plant can not utilize nitrogen in gas form; it must be converted to the nitrate or ammonium forms.


• Nitrogen cycle- is the process that converts nitrogen gas to forms that are usable to plants.

• A symbiotic relationship that exists between bacteria and legume plants utilized to convert nitrogen gas (N2) to ammonium ions (NH4+)


• Bacteria decompose plant material, nitrogen is formed

• Nitrogen becomes available to plants in the form of ammonium ions when the bacteria die.


• Most of the ammonium ions are converted to nitrite ions by Nitrosomas bacteria

• Nitrite ions undergo another reaction with Nitribacter bacteria to covert the nitrite to nitrate. This process is called Nitrification.


• To complete the nitrogen cycle , a process called Denitrification occurs.

• This process involves the loss of nitrogen from the soil.

• Nitrogen is remove from soil by; plants, leaching, or denitrification


• Denitrification occurs in soil that have no oxygen because of saturation from water.

• When soils are saturated with water, bacteria will convert the nitrate to nitrogen gas which is then lost to the atmosphere.

• Nitrogen can also be added to the soil by lightning or commercial fertilizers

Define pH and discuss its role in plant nutrition.

• pH- measure of alkalinity or acidity of a substance

• pH scale runs from 0 to 14, 0 being extremely acidic, 7 as neutral, and 14 as extremely basic.


• Changes in pH can be made by adding sulfur or gypsum to lower pH ( make more acidic)

• By adding limestone to increase pH ( make more basic)

• Plants grow best with pH range of 5.5-8.0


• Soil pH is important to agriculturists because certain nutrients become unavailable to plants if pH value is too high or too low

• The amount of nitrogen, phosphorus, and potassium that are available is dependent upon soil pH.

Explain the use of fertilizers

• Fertilizers are materials that are added to growing media to provide the plant with the necessary nutrients.

• Adding fertilizer to plants can increase their productivity.


• Fertilizers can be grouped into two major categories

• Complete fertilizers contain all three macronutrients, Ex. 12-12-12

• Incomplete fertilizers lack at least one macronutrient, Ex 18-46-0


• Fertilizer analysis contain three numbers ex. 12-4-8.

• First number is percentage of pure nitrogen

• Second number is percentage of pure phosphorus

• Final number is percentage of pure potassium


• When the numbers from analysis do not add up to 100% the remaining weight is comprised of filler, made up of the remaining essential plant nutrients.

• Fillers- are used to ensure a more even application of the fertilizers.


• Producers can determine nutrient deficiencies by three ways

• Deficiency symptoms- pales leaves mean lack of nitrogen or stunted growth and reddish-purplish is phosphorous deficiency

• Soil testing

• Tissue testing

Discuss the effect of temperature on plant growth.

• All chemical reactions in a plant, including photosynthesis and respiration fall under a term Metabolism

• Temperature affect the speed of metabolism

• This is because enzymes that drive the reactions are sensitive to temperature.


• Cool or cold temperature slow metabolic process

• Warmer temperature speed metabolic process

• Most plant show optimum growth when night temperature are 10 to 15 degrees cooler than day temperature.


• Under ideal conditions photosynthesis occurs at a high rate during the day.

• Cooler temperature at night slow respiration

• For growth, the rate of photosynthesis must exceed that of respiration.


• High temperature can speed rate of respiration beyond that of photosynthesis

• As a result, the product of photosynthesis are used more rapidly than they are produced.

• In many plants, photosynthesis shuts down at temperature above 86F.

Describe plant responses to temperature.

• The change of daily temperature is called Thermoperiod.

• When daily change, it influence plant response such as flowing, the plant are said to be Thermoperiodic.

• Poinsettias and chrysanthemums are thermoperiodic plants.

• They initiate flowers when temperature become cooler and days grow shorter.


• Cool season crops-meaning they prefer cooler growing temperature and are tolerant of frost.

• Ex. Wheat, oats, barley, rye, spinach, and lettuce

• When temperature rise in combination with longer days, spinach and lettuce initiate flower production.


• Warm season crops require warmer temperature for best growth.

• Ex. Cotton, corn, soybean, tomatoes, and sorghum


• Vernalization- require a cold treatment for physiological processes to occur

• Tulips and narcissus require vernalization to flower.

• Some grains including winter wheat, also require vernalization.

• Apples require 1,000 to 1,200 hours of temperature between 32Fand 45F to break their rest period


• Seeds of some plants have a dormancy mechanism that is broken by a cold period.

• Seeds do not germinate until the seed undergone a cold period.

• This cold requirement for seeds id know as Stratification.

Explain Hardiness

• Hardiness –is a plant ability to tolerate cold temperatures

• Plants can be classified as hardy or non-hardy

• USDA established a plant hardiness zone map for the Untied States

Explain Hardiness

• The map shows eleven zones of temperatures.

• It is valuable in selecting plants adapted for growing in those areas.

• Heat also plays a role in the performance of plant species.

• Some plants are more sensitive to heat than others

Explain Hardiness

• Plant heat zone map- developed by the American Horticultural Society to help identify areas in which landscape plants can flourish.

• The map shows 12 zones

• Each zone reflects a rating of summer heat based on the average number of days above 86F

Explain Hardiness

• Eighty-six is a temperature at which plants are unable to process water fast enough to maintain normal functions.

• Plants also experience damage to cellular proteins.

Explain growing degree days

• Growing degree days (GDD)- is a measure of temperature requirements for plants and can be used to estimate growth and development.

• The basic concept of growing degree days is that plant development will occur when temperatures exceed a base temperature.


• Maximum temperature plus the minimum temperature in a day divided by 2 minus 50.

• Fifty is selected as the constant because corn grow very little at temperature of 50F or below.


• Growth is also checked when temperature rise above 86F, so all temperatures recorded above 86F are counted as 86 in the formula.

• Most corn hybirds have fairly specific GDD specifications.


• Example- low 60 and high was 90F

GDD- is 60 + 86= 146/ 2 =73-50=23

GDD are adding during the growing season.

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Determining Plant Nutrients, Fertility and the Influence of Temperature on Plants.

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