Erosion of soil causes loss of nutrients.
Slide 19
Contour tillage helps reduce soil erosion
Slide 20
Erosion can be reduced by:
Planting trees as windbreaks
Terracing hillside crops
Cultivating in a contour pattern
Practicing no-till agriculture.
Slide 21
Preventing Soil Compaction
Soil compaction from heavy equipment reduces pore space between soil particles.
Soil compaction slows gas exchange and reduces root growth.
Slide 22
Some areas are unfit for agriculture because of contamination of soil or groundwater with toxic pollutants.
Phytoremediation is a biological, nondestructive technology that reclaims contaminated areas.
Plants capable of extracting soil pollutants are grown and are then disposed of safely.
Slide 23
Concept 37.2: Plants require essential elements to complete their life cycle
Plants derive most of their organic mass from the CO2 of air, but they also depend on soil nutrients such as water and minerals.
Slide 24
A chemical element is considered an essential element if it is required for a plant to complete its life cycle.
Nine of the essential elements are called macronutrients because plants require them in relatively large amounts. The macronutrients are carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium.
Eight of the essential elements are called micronutrients because plants need them in very small amounts. These are chlorine, iron, manganese, boron, zinc, copper, nickel, and molybdenum.
Slide 25
Hydroponic culture - used by researchers to determine which chemical elements are essential
TECHNIQUE
Control: Solution
containing all minerals
Experimental: Solution
without potassium
Slide 26
The 17 Essential Elements = Micro- and Macro- Nutrients
Slide 27
Symptoms of mineral deficiency depend on the nutrient’s function and mobility within the plant.
Deficiency of a mobile nutrient usually affects older organs more than young ones.
Deficiency of a less mobile nutrient usually affects younger organs more than older ones.