Crss 3060 - Exam 2

Growth factor for plants

any environmental factor that affects or determines plant growth

air, light, water, temp, humidity, nutrients

essential factors for plants

a factor that a plant cannot live without (ex: water)

law of minimum

a plant can only be as productive as it’s most limiting nutrient

essential plant elements

primary: N, P, K

secondary: Ca, Mg, S

nutrient availability

how much nutrients are available for the plant to uptake, not necessarily how much is in soil total

nitrogen

most limiting nutrient, major component of amino acids

N losses

denitrification, leaching, erosion

phosphorus

solubility is low, could also be be limiting nutrient

potassium

high presence in soil, but only 2% is available (rest is either non-exchangeable or in mineral form)

calcium and magneisum

Ca: 50-80% of CEC cations, required for root tip elongation

Mg: 5-15% of CEC

sulfur

found in humus, held on AEC sites

micronutrients

needed in very small quantities, availability is controlled by pH

micronurtient cations

Zn, Mn, Cu, Co, Fe

toxic or unavailable at pH 4.5, unavailable at ph 7.5+

micronutrient anions

Mo, BO, Cl

nutrient solubility as a function of pH

all nutrients have different availability depending on pH. the best pH is ~6, this is where all nutrients are at a sufficient availability