bio1ps201201

Soil and Plant Growth

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Physical support

Water

Nutrients

Air

http://wps.prenhall.com/wps/media/objects/5309/5437119/Figures/chap01/Fig01-3.jpg

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Brady, N.C., Weil, R.R. (2008), 14th ed., Fig. 01-3

Temperature moderation

Protection from toxins

Function of Soil

Sunlight

Air

Soil

Source of all water and mineral nutrients (and then,

mineral nutrients for all animals)

No soil - no plants (except for lichens) Furka

ME

Please Concentrate!

•P is concentrated 1000-fold in plants compared with soil

•Water from apparently dry soil is absorbed and concentrated by plants

•Requires a !ne, extensive tissue system (‘roots’) penetrating soil

•kilometres of roots per cubic metre of soil

•immobility of plants

Extensive root

system

Roadtrip, Anyone?

http://www.agroatlas.ru/content/cultural/Secale_cereale_K/Secale_cereale_K.jpg

Secale cereale

rye

Essential Nutrients

C.B. HOPKiNS CaFe

Closed Monday Morning and Night

Cu Zoon, the Mg

Macronutrients		Micronutrients
from air and water	mostly from soil solids	from soil solids
carbon (CO2)	nitrogen	copper
hydrogen (H2O)	potassium	iron
oxygen (O2, H2O)	calcium	manganese
	magnesium	nickel
	phosphorus	zinc
	sulfur	boron
		chlorine
		molybdenum

Macronutrients

Nutrient	Relative concentration
N	1000
K	250
Ca	125
Mg	80
P	60
S	30

Micronutrients (trace elements)

•made up of all the others

•relative concentrations in plant tissue of less than 5

•only very small (trace) amounts required from soil

Soil Fertility

•is determined by the presence and availability of nutrients in soil for uptake by plants

•is the ability of the soil to support productive plant and, ultimately, animal (including human) life

Soil Layers

Also called "horizons"

O horizon - leaf litter layer on surface of the mineral soil, often with high biological activity

A horizon - upper layer of mineral soil darkened by accumulation of organic matter and in which biological activity is greatest

B horizon - zone of accumulation of !ne clay particles and mineral nutrients

O A

B

C

D

C horizon - zone of weathering of bedrock

D horizon - bedrock

Soils in Australia

http://www.anra.gov.au/topics/soils/maps/national/soil_atlas.gif

More info on soils:

http://www.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/soil-home

Soil Formation

Rock

http://blog.oregonlive.com/themombeat/2009/02/

rock_solid_solutions_small.jpg

physical breakdown	chemical breakdown
(disintegration)	(decomposition)
• temperature	• hydration
• abrasion, e.g. wind,	• hydrolysis
water, ice	• dissolution
• plants and animals	• acid reactions
	• oxidation/reduction
	• complexation