APES Soil Chemical Properties

chemical tests

look at chemical properties of soil, used to determine fertilizers and other treatments

nitrogen

-used for chlorophyll (which makes plants green)

-usually nitrates (NO₃-)

-nitrates and soil negatively charged (repel each other)

-leeching (as H20 percolates through soil, it transports nitrates with it)

Phosphorus

-used for root growth, fruit, stem and seed developments

-disease resistance, general plant health

-genetics (DNA needs phosphorus)

-doesn’t leech as easily as nitrogen

potassium

-used for growth

-disease resistance, general plant function

-fruit/vegetable flavor development

-breaks down slowly, most soils are not deficient

fertilizers are packaged with N-P-K labels, based on percent by weight. ex. 10-5-3 would be…

10% N, 5% P, 3%K

basic pH

higher numbers

acidic pH

lower numbers

most plant’s pH level range from

4-8

plants are affected by pH because

different pHs change availability of nutrients

pH changes nutrients into

unusable forms