Soil Macronutrients

SOIL MACRONUTRIENTS C arbon-Hydrogen-Oxygen-Nitrogen-Phosphorus-Potassium

Nutrients

Macronutrients Needed in larger

quantities Micronutrients

Needed in smaller quantities

Non-Fertilizer Nutrients

Cannot be supplied in a fertilizer

Come from Water & Air (H2O & CO2)

Carbon Hydrogen Oxygen

Primary Macronutrients

Nitrogen Phosphorus Potassium

Complete fertilizer must contain all 3

Secondary Macronutrients

Calcium Magnesium Sulfur

Nitrogen

Encourages Growth Gives plants a dark

green colorDeficiency: - Plant turns lighter green - Yellowing leaves- Slow growth

Phosphorus

Root Development

Encourages Flowering

Improves Winter Hardiness Deficiency

Purplish coloration to leaves

Stunted Growth

Potassium

Increases disease resistance

Thickens cell walls

Aids in the transport of food in the phloem Deficiency

Yellowing, death of tissue at the tips.

FERTILIZER PROBLEMS For Proper Fertilizer Application

Calculating Pounds of Fertilizer

A bag of fertilizer has 3 numbers on it. N-P-K 10-15-20

Weight of Bag X % of Nutrients = Lbs. of Nutrient in the bag.

Practice Problem

10% Nitrogen- 15% Phosphorus-10% Potassium

The bag weighs 50lbs. How many pounds of Nitrogen are in this

bag of fertilizer?

50 x .10= 5lbs. Nitrogen

Try it on you own: Problem #1

You purchased a bag 33 pound bag of 25-5-15 vegetable fertilizer for your garden this summer. If you wanted to re-create this fertilizer for next year, how many pounds of nitrogen, phosphorous and potassium would you need?

Answers

Nitrogen: 0.25*33lbs.= 8.25 lbs.

Phosphorous: 0.05*33lbs.= 1.65 lbs.

Potassium: 0.15*33lbs.= 4.95 lbs.

Try it on your own: Problem #2

You are mixing a fertilizer for your flower garden. You ended up with 50 pounds of fertilizer. The fertilizer contains 5 pounds of nitrogen, 5 pounds of phosphorous and 15 pounds of potassium. You want to patent your product, but you need to include the ‘three numbers’.

What percentage of the fertilizer is nitrogen? Phosphorous? Potassium?

Answer

Nitrogen: 5 lbs./50 lbs.= 0.10 = 10%

Phosphorous: 5 lbs./50 lbs. = 0.10 =10%

Potassium: 15 lbs./50 lbs. = 0.30 = 30%