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12 - Necessary Nutrients. 12.1 Soil Nutrients and Fertilizer. What is soil?. Dirt is MISPLACED soil Soil is a major source of plant nutrients What factors make a “good” soil? Physical properties Biological properties Chemical properties. Fertilizers.
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12 - Necessary Nutrients 12.1 Soil Nutrients and Fertilizer
What is soil? • Dirt is MISPLACED soil • Soil is a major source of plant nutrients • What factors make a “good” soil? • Physical properties • Biological properties • Chemical properties
Fertilizers • Fertilizers are substances rich in plant nutrients and used to increase the fertility of soils. • They include • Nitrogen (N) • Phosphorus (P) • Potassium (K) • Fertilizers are labeled with an N-P-K ratio such as 10-10-10
Concerns with Fertilizers • Run-off is water that runs off fields an carries nitrates with it. • Runoff water ends up in streams, lakes and other water bodies. • Runoff can contaminate drinking water • Nitrates cannot be “seen” in the water but through a simple test the water can be tested for nitrates. • Run-off can be decreased by carefully regulating the amount of fertilizer put on fields.
Soil Testing Lab • Complete the Part A and Part B of the procedures • Complete the Individual analysis questions on page 151 after you have completed the procedures.
Soil • Is a complex mixture of living and non-living matter that contains: • Air • Water • Minerals • Particles • Organic Material • Organisms such as bacteria, fungi, worms and insects. SOIL IS THE FOUNDATION OF THE ECOSYSTEM!
Soil Structure • Soils form from rock and very greatly depending on the age of the soil and the climate of the region • Young soils are thin and rocks and they ability to support plant growth is limited to small hearty plants such as grasses and wildflowers. • Mature soils built up over time, as plants grow and die they break down the rock and leave behind organic material
Soil Profile • Mature soils consist of layers: • O = Organic material • A = Top soil • Dark in color • High in humus • B = Sub Soil • Originated from the rock • Leached nutrients • Some roots of large plants • C = Parent Material
Nutrients • Micronutrients • Cl • Fe • B • Mn • Zn • Co • Mo • Ni • Macronutrients • N • P • K • S • Mg • Ca • -Create your own mnemonic device
Soil Nutrients • Nitrogen • Is a part of every living cell • Stimulates above ground plant growth and is responsible for rich green color • Can only be absorbed from plants when it is present in the soil in the form of nitrate compounds • Nitrates dissolve easily in water, there for move in and out of soil easily
Soil Nutrients • Phosphorus • Essential for the growth of new seedlings • Promotes early formation of roots, seeds and fruits • Cannot be absorbed by plants unless it is present in the soil as phosphate compounds
Soil Nutrients • Potassium • A catalyst necessary for plant metabolism. • Strengthens a plant’s resistance to disease
Calcium • Calcium is present in the cytoplasm at levels that would indicate that it is a micronutrient, ~0.1 µM, in order to prevent interference with the high levels of P. • Small fluctuations in Ca levels in the cytoplasm are part of signaling mechanisms for environmental stress. • Function: Structural, in the cell walls of shoots and roots.
Magnesium • The central ion in chlorophyll molecule, accounts for <25% of total plant Mg • Mg in the cytoplasm is related to enzyme activation: for example, the substrate for ATPases is MgATP. • Additional Mg is present in the cell wall • Deficiency: Grass tetany for livestock
Sulfur • Essential to growth and physiological functioning • Needed to develop amino acids cysteine and methionine
Law of Minimum • Created by Justus von Liebig • Yield is proportional to the amount of the most limiting nutrient, whichever nutrient it may be.
Calculation #1 • You have a 5,000 square foot yard • Need 5 lbs of N per 1,000 feet • You have 100 lbs of 22-5-10 fertilizer • How many pounds do you need to use?
Calculation #2 • You have a 4,000 square foot yard • Need 5 lbs of N per 1,000 feet and 2 lbs of K for every 1,000 feet • You have 100 lbs of Urea 64-0-0 and Green Zone 5-5-20 • How much do you need to use of each fertilizer?
Homework Problem • You have 2.5 acre yard • An acre has 43,560 square feet • Need: • 5 lbs of Nitrogen for each 1,000 sq. feet • 1 lbs of Phosphate for each 1,000 sq. feet • 5 lbs of Potassium for each 1,000 sq. feet • Pick your fertilizers: • Kevin’s Manure 64-0-0 --Trey’s Triple 10-10-10 • KU Basketball 0-0-15 --John’s Jungle 0-51-0
Soil properties • Porosity • A measure of the volume of space the lies in the openings between soil particles.
Permeability • The rate at which fluids can move though the soil
Water Retention • The amount of water the soil can absorb. • Which soil type would have the ability to hold more water, sand or clay? • Why?
Soil Lab • Complete the procedure and analysis questions on page 156 and 157.
Ag Ed Tube • Soil Quality, Conservation and Food Production