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

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.

12.2 Dirty Differences

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 Macronutrients –N –P –K –S –Mg –Ca Micronutrients –Cl –Fe –B –Mn –Zn –Co –Mo –Ni -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 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 and Green Zone 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 Trey’s Triple –KU Basketball John’s Jungle

12.3 Soil Components and Properties

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 ProductionSoil Quality, Conservation and Food Production

12.4 Mineral Mania