Section:Plant & Soil Science Unit:Unit 7: Soil Management Lesson TitleLesson 1: Introduction to Soil Fertility and pH with Soil Sampling Lab
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Section:Plant & Soil Science
Unit:Unit 7: Soil Management
Lesson TitleLesson 1: Introduction to Soil Fertility and pH with Soil Sampling Lab
Most popular macronutrients in soilNitrogen------NPhosphorus-----P(usually in the form of P2O5)Potassium-------K(usually in the form of K2O)Slide #2
What does nitrogen do?Slide #3Most popular macronutrientIt give a plant its green colorAssists with rapid growth and vigorPromotes seed and fruit development Increases protein and yield
Phosphorous (P2O5) is important why?Slide #4Aids seedlings to germinate Very important in the early stages of the crop Stimulates root growth
What does Potassium (K20) do?Slide #5Responsible for production of carbohydrates in the plant, Produces plumper seedsActs as the water valve for letting water in and out of the plant.
What are fertilizers?Slide #6Help plants get the nutrients they need by adding deficient materials to the soil.
It makes nutrients more available to the plant to get what it needs
How can we find out what is in the soil?Slide #7Visual Inspectionnot accurateTissue Culturesaccurate but expensiveSoil Testmost widely accepted form of testing
What forms are fertilizers found? Dry (granules) Liquid (usally diluted with water)Gas (anhydrous ammonia) Solids (manure)Spikes (concentrated quantities placed in ground and allowed to dissipate through soil)Slide #8
Reading a bag of fertilizerSlide #920-15-10 20% Nitrogen15% Phosphorus10% PotassiumN -P- K
How many pounds are in there?Assume the bag is 100 pounds 20% Nitrogen means there is 20 pounds of Nitrogen
Phosphorus in the form of P2O5 15% X .44=6.6 lbs
Potassium in the form of K2O 10% x .83= 8.3 lbsFor bags smaller than 100 lbs, multiply your pounds by the pounds in the sack then divide by 100. Example of 50 lb sack.8.3x50/100 = 4.15 lbs of Potassium
Math problemsSlide #11A 50# bag of 10-10-10 #N#P#K__
A 50 # bag of 10-20-15#N#P#K__
A 100# bag of 20-10-0#N#P#K__
Answers to math problemsA 50# bag of 10-10-10 #N 5 #P 2.2 #K 4.15
A 50 # bag of 10-20-15 #N 5 #P 4.4 #K 6.225
A 100# bag of 20-10-0 #N 20 #P 4.4 #K 0Slide #12
What is pH?pH is the scale we use to measure acidity (sour) to basic (bitter).
What is the range of pH?
You are right the range is 0-14. Slide #13
pH ScaleSlide #14
What does pH measure?pH is the measure of how an item reacts with water. If it gives off hydrogen ions (H+) it is an acid. An example would be hydrochloric acid. When it meets water it forms hydrogen ions and chloride ions.
A base give off hydroxide ions when reacting with water. Sodium hydroxide is a base because it forms sodium ions and hydroxide ions when mixed with water.
Why do we need to know pH?Knowing the pH of our soil is important for two reasons:It allows us to figure what amendments we might need to make the soil more efficient for the crop we are to be growing
It also determines nutrient availability (some nutrients become unavailable to plants at low or high pH levels)Slide #16