soil fertility quiz 2 Flashcards
what are the necessary macronutrients
carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulfur
what are the necessary micronutrients
iron, manganese, zinc, copper, boron, molybdenum, cholrine
what is a soil colloid?
include soil particles measuring 2 micrometers or less in diameter
what makes up a collodial component of a soil?
clays and humus
what is an ion
an atom or molecule in which the total number of electrons is not equal to the total number or protons, giving the atom a net positive or negative charge. ions can be created by both chemical and physical means
what is a cation
and positively charged ion
what is an anion
a negatively charged ion
what are the most common soil cations?
calcium, magnesium, potassium, ammonium, hydrogen, and sodium
cations in soil solution are readily available for plant uptake while cations on CEC sites are ______________________
moderately available for uptake
if the cation is actually part of the soil structure, it will do what?
slowly be available to the plant
what are some common annions?
chlorine, nitrate, sulfate, and phosphate
anions can have more than one ___________ and may be combinations of ____ with _________
negative charge, elements with oxygen
what is CEC? describe it
cation exchange capacity, the amount of exchangeable cations per unit dry weight of soil
CEC depends on what
soil structure
what soil processes do CEC’s affect?
weathering of soil minerals, nutrient absorption by plants, leaching of electrolytes, buffering of soil pH
what is BC? describe it
Buffer capacity, the ability of a soil to resist change
CEC determines what?
how you can supply many important nutrients
what is the current USGA spec for clay percentage?
3%
what are some characteristics of low CEC soils
- low nutrient levels
- rapid changed in nutrient levels
- leaching
- salinity build up
- pH changes
- difficulty in monitoring nutrient status and levels
- establishment problems
what are nitrogen problems in low CEC soils?
- leaching of NH4+
- maintaining adequate N levels for growth
- N carrier effect on pH
- NO3- can also leach quickly due to high percolation rates
what is the primary problem in low CEC soils
potassium
major buffering occurs where
at the CEC sites
when is the best time to determine your soil CEC
at construction
