understanding soil air/water dynamics. no-till soiltilled soil porosity the soil’s respiratory and...

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Understanding soil air/water dynamics

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Page 1: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Understanding soil air/water dynamics

Page 2: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

No-till soil Tilled soil

Porosity

the soil’s respiratory and circulatory system

(Young and Ritz, 2000)

White zones are pores > 1mm

Page 3: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

http://www.mtm.kuleuven.ac.be/Research/NDT/IDO_SHerman_final.ppt

Soil pores come in many

sizes and shapes

Page 4: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Intensive tillage Long term no-till

AgriCanada

plow pan

well connected network of biopores

Page 5: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Effect of previous 20

years of rotations on

SOM and corn growth on Beltsville silt loam in Maryland

Effect of previous 20

years of rotations on

SOM and corn growth on Beltsville silt loam in Maryland

Continuous corn with tillage

Continuous bluegrass sod

Page 6: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

25 yrs of CT corn25 yrs of CT corn

20 yrs of bluegrass, then 5 yrs CT corn

20 yrs of bluegrass, then 5 yrs CT corn

Page 7: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

After adding waterAfter adding water

25 yrs of 25 yrs of conventiconventional onal corncorn

25 yrs of 25 yrs of conventiconventional onal corncorn

20 yrs of bluegrass, then 5 yrs conventional corn

20 yrs of bluegrass, then 5 yrs conventional corn

After adding water

Page 8: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Least Limiting Water Range

dry Soil water content, cm3/cm3 *100 wet

20 25 30 35 40 45 50 55

Ro

ot

gro

wth

rat

e LLWR for loose well-aggregated soil

LLWR for compacted soilNot enough O2 for root respiration

Soil too hard for roots to penetrate

From Weil, 2003Ray Weil

Page 9: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

June July August

So

il M

ois

ture

(%

of s

atur

atio

n)

100

75

50

25 8”16”

How does compaction affect a soil’s least limiting water range?

Uncompacted soilCompacted soil

LL

WR

Page 10: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Compacting effects of wheel traffic

Chapter 7 in Ross (1989)

Cone resistance

Bulk density

Number of wheel passes

Page 11: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

AgriCanada

Without restricted traffic, most field surfaces receive traffic each year

Page 12: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

(Watts and Dexter, 1997)

Compaction

Soils with more OM are weaker when dry and stronger when wet !

Tillage and traffic damages wet soils !!!

Page 13: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Why are soils more compactible at field capacity than at saturation?

Soil will flow before water filled pores collapse

Page 14: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

http://www.bettersoils.com.au/module6/6_3.htm

< 1 MPa1 - 3 MPa> 3 MPa

1 MPa = 145 psi

Prenetrometer pressureMoisture strongly affects penetration resistance!!The same soil can be hard

when dry and weak when wet.

Page 15: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Understanding bulk density

Soil structure must be intact and soil must be oven dry

Page 16: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

It is often said that bulk densities > 1.6 g / cm3

are root restrictive… Is this true ??

Page 17: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones
Page 18: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Compactive force

Page 19: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

So how does compaction impact soil water relationships ?

Loss of drainage pores

Gain in small pores

Page 20: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Plant available water

10-30 μm

Drainage pores

Unavailable water

Adapted from Buol (2000)

Most available

Soil circulatory system

~0.2

μm

less

av

aila

ble

Field Capacity

Wilting point

Saturation

Page 21: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Impact of texture on soil water

Available water

Brady and Weil, 2002

35 - 14

21%

21% of 12”

~ 2.5”

Page 22: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

SOM increases plant available H20

Adapted from Brady and Weil (2002)

Page 23: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Measuring infiltration rate

Page 24: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

12”

6”

50% porosity

satu

rati

onMacropores

Plantavailable

H2O50% plant

available H2O

2.5”1.25”3.5”

Total water at field capacity

50% solids

6”

Visualizing water in a 1 foot layer of soil

Page 25: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

50% plantavailable H2O

1.25”

How much water is need to bring the soil to field capacity ?

What will happen if more than 1.25” of water infiltrates into this soil ?

Water will percolate deeper than 1’

Page 26: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

How fast does water move through soil ?

Flow rate = Area*Ksat *pressure head/lengthBrady and Weil, 2002

Darcy’s Law

Hyd

raul

ic c

ondu

ctiv

ity

Page 27: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Permeability = Hydraulic conductivity

Flow rate ~ pore radius4

Page 28: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Coarse textured layer

Fine textured layer

How does the presence of a coarse textured layer under a fine textured layer affect

percolation ?

Page 29: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

http://www.personal.psu.edu/asm4/water/drain.html

Coarse textured layer

Water will not enter the coarse

textured layer until the upper layer is near saturation

After water enters the coarse textured layer, it

will percolate more quickly.

Page 30: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Does a thin layer of coarse

material improve

drainage ?

NO !

Thin layer with coarser texture

Page 31: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Slit filled with coarse material

Soil capped slit

Systems for rapidly draining surface water should be open to the surface

Page 32: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Slit trenching equipment

Outlets are needed !!

Page 33: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

The current guide reflects recent developments in drainage science and technology. Most of

these are related to new equipment and materials, widespread use of computers, and

water quality considerations. It includes information not in the previous edition on

pipeline crossings, water and sediment control basins, drain fields for septic systems, design of drainage water management systems, and

design charts for smooth-walled pipes.

Page 34: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

In Illinois, soil drainage is rated using a number (1 to 4) and letter (A or B) system. The number indicates the degree of soil permeability. The letter indicates the

natural drainage.

1

Rapidly permeableMore than 6 inches per hour

Moderately rapidly permeable

2 to 6 inches per hour

2Moderately permeable

0.6 to 2 inches per hour

3Moderately slowly permeable

0.2 to 0.6 inch per hour

4

Slowly permeable0.06 to 0.2 inch per hour

Very slowly permeable

less than 0.06 inch per hour

IL Permeability classes

Page 35: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

A

Poorly drained

The water table is at or near the surface during the wetter seasons of the year

Very poorly drained

The water table remains near, at, or above the surface much of the time

BSomewhat poorly drained

The water table is near the surface only during the very wettest periods

Page 36: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones
Page 37: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Bioreactor vs. standard tile outlet

Page 38: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones
Page 39: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones
Page 40: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones
Page 41: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

One calorie is the amount of thermal energy required to raise the temperature of one gram of water by one Celsius degree.

3000 calories of thermalenergy enters each cup.The temperature of thewater on the left rises by30 Celsius degrees.

By how much does thetemperature of thewater in the cup on theright rise ??

Page 42: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Why does soil heat up faster than water ?

The heat capacity of water is ~ 5 times higher than the heat capacity dry soil.

As a result, moist soils heat up and cool down more slowly than dry soils.

Page 43: Understanding soil air/water dynamics. No-till soilTilled soil Porosity the soil’s respiratory and circulatory system (Young and Ritz, 2000) White zones

Water has a high thermal conductivity

Air has a low thermal conductivity

What can be done to maximize geothermal

heat transfer ?

compacted vs. loose ?

moist vs. dry ?