2. pH
• How acidic/basic a soil is
• Can be acidic/basic/neutral
• Imp: affects ability of plants to
absorb nutrients; tells which plants
can be planted where
• Measure: colorimetric test; electronic tester
3. Nitrogen
• Key factor for plants; taken up as nitrates
• Imp: most common nutrient in plants; inc.
crop yields; inc. foliage
and fruits
• Measure: colorimetric test
4. Phosphorous
• Present through absorption of iron or
aluminum oxides; comes from humus
• Imp: forms plant buds and roots; inc. yields
• Measure: colorimetric test
• Comes from mining
5. Potassium
• Most common nutrient in soils but not always
readily available; comes from breakdown of
rocks
• Imp: catalyst in plant metabolism; regulates
water, ATP, nitrogen uptake, and protein
synthesis
• Measured: turbidimetric test with indicator
chart
6. Temperature
• Imp: provides guidance for when to plant
crops; higher temps cause faster plant growth
and absorption of nutrients; water loss is
higher with high temps
• Measure: electronic thermometer
