A group of Udon Thani's Iron Ladies shout "No Potash!", a phrase

that has become their battle cry in a four year struggle against a

proposed mine in their village.

Answer the following questions based on information in 2 readings:

1) The New Thai Capitalism: Development or Disaster?

http://clpmag.org/article.php?article=The-New-Thai-Capitalism-Development-or-

Disaster_162

2) The potash project: Thailand's first underground mine – Canadian Mining

Journal (abridged version should be attached)

Questions:

1) Who are the “Iron Ladies” and what is their mission? Do you think the age and

gender of the “Iron Ladies” has affected the way Thai society, government

officials and industry reps have responded to their protests? What if the protests

were led by college students? or young male farmers?

2) Why did the mining company lobby for changes in Thailand's Mineral Act of

2002? What has the mining company done to address public skepticism about

foreign owned companies?

3) Identify several potential negative environmental impacts of the proposed

mining project.

4) What types of technologies does the mining company plan to employ to minimize

negative environmental impacts?

5) What types of public benefits does the mining company claim will come about if the

mine is developed? Do any of the villagers believe these claims?

6) Estimate the potential economic value (in US dollars) of the Udon potash reserves.

Assume 500 million tons of potash ore with an average K2O content of 20% can be

economically extracted. Assume a world price of $500 per ton of potash fertilizer

containing 60% K2O.

7) How do the 2 articles differ in their tone? (Hint: compare words used to describe

local opposition to the mine)? Do you think one article is more likely to be accurate or

objective than the other? Explain.

8) How do you think members of your community would react if a mining company

wanted to extract minerals from deep underneath your community and claimed that

the mining would *not* significantly disrupt current land uses or harm the

environment?

9) As far as I can tell, mining still has not begun in Udon and the Iron Ladies have

remained unwavering in their opposition. What do you think will happen? Do you think

a compromise is possible?

Why is potassium represented by the symbol K ?

39K is the dominant isotope. 40K (radioactive) and 41K (stable)

are used as tracers.

In Latin and German, Kalium = Potassium

Element Total Exchangeable Solution

K 38,000 190 10-30

Ca 8000 2250 60-120

Mg 6000 450 10-20

N 3500 -na- 7-25

P 900 -na- 0.05-0.15

S 700 -na- 2-10

1 kg/ha = 0.89 lbs/ac

The total potassium content of most Midwest soils is

tens of thousands of lbs per acre-plow layer

but most of the K is locked up in minerals like

K feldspar that release K very slowly

Typical quantities of nutrients in Midwest farm soils (kg/ha)

Depth of

loess cap

A loess cap covers

about 2/3rds of IL

So where did all

this potassium

come from?

K-rich

primary

minerals

Glacial

outwash

http://www.archive.org/stream/potassiumfromsoi00hopk#page/n3/mode/2up

Cyril Hopkins

wrote a ground-

breaking

bulletin on

potassium in

IL soils almost a

century ago.

Is this possible?

Luxury consumption

Soil solution

K+

K+

K+

K+

K+ K+ K+ K+

K+ K+ K+ K+ Trapped K

K

K K

K

Soil Minerals

(feldspar, mica)

Soil Colloid

Soil Colloid

Soil Colloid

K

Unavailable (90 to 98%)

Slowly available (1 to 10%)

Readily

available

(0.1 to 2%)

Important potassium concepts

No significant gaseous forms

3rd most likely (after N and P) to be plant

limiting

Non-toxic at high concentrations

Does not promote eutrophication

(unlike N and P)

Role of potassium in plant nutrition

Remains in ionic form inside plants (rather than being

incorporated into organic molecules)

Very important osmotic regulator (lowers water

potential inside of plant cells)

Activator of over 80 enzymes

1-4% of plant dry matter (similar to N)

Important for tolerance of environmental and biotic

stresses (drought tolerance, winter hardiness,

resistance to fungal pathogens, resistance to insects)

Important for crop quality (flavor, color, stem strength)

Necrotic leaf margins are associated with

potassium deficiency

Uptake of K by plants requires an active root system, especially in

the soil zone where plant-available K is located !!

When this soil zone is dry, uptake is limited. Anything that exerts additional stress

or limits root growth--compacted soil layers, root pruning, side-wall smearing--

further reduces K uptake, especially when root growth is restricted in the zones of

highest available K.

K deficiency symptoms can occur even when soil test K levels are high

Corn in ridge-till and no-till

systems are often first to

show K deficiency symptoms,

but they can occur in other

tillage systems as well.

Crop removal of K by grain crops is small compared to forages

Crop Yield N P2O5 K2O

Bell Peppers 180 cwt 137 52 217

Cabbage 20 tons 130 35 130

Peas 25 cwt 164 35 105

Potatoes (white) 30,000 lb 90 48 158

Snap Beans 4 tons 138 33 163

Sweet Corn 90 cwt 140 47 136

Tomatoes 20 tons 120 40 160

Vegetable crops use a lot of potassium !

Many veggies use more K2O than N!

Average K2O application rates for fruit and vegetable crops in the US

1 lb of elemental K = 1.2047 lbs of K2O

Crops do not actually take up K2O

Fertilizers do not actually contain K2O

The more highly weathered

soils in southern IL tend to have

low CECs. Pockets of sandy

soils (grey shaded areas) in

northern and central IL also

have low CECs

Most soils in the “high” region

shown on this slide have CECs

12 centimols / kg.

1 centimol/kg = 1 meq / 100 g

Most soils in the “low” region

shown on this slide have CECs

< 12 centimols / kg.

The U of Ilinois recommends

higher soil test K for soils with

higher CEC!

Crop response to extractable K in low CEC soils

Suffic

iency

No m

ain

tena

nce

Crop response to extractable K in low CEC soils Crop response to extractable K in high CEC soils

Suffic

iency

No m

ain

tena

nce

Iowa State has updated their K recommendations

for corn and soybeans

How do you convert between ppm and lbs/acre?

http://www.ipni.net/ipniweb/portal.nsf/0/c13f0cf310f1903e062577c7005a4bd7/$FILE/2010%20Critical%20P%20and%20K%20Maps.pdf

Variation in soil test K critical levels across the US and Canada

Why do different states have different soil test critical levels?

Part of the reason is differences in soils but climate, cropping

systems and data interpretation philosophy also matter.

Some labs recommend much higher K levels for soils with high CECs

http://www.spectrumanalytic.com/support/library/ff/Soil_test_P_and_K_buildup_and_drawdown.htm

Soil testing methods for potassium

used by US labs in 2005

Traditional method

NH4+ exchanges with

K+ on soil colloids

Universal

extractant

adopted by more

labs every year

Soil Test K survey results (> 4 million samples from ~ 60 labs)

Change between 2005 and 2010 % of samples below critical level

Declines in many states but not IL

Soil test values for K fluctuate during the year

K is more available in wet soils

Drying of moist samples increases soil test K

General rule of thumb:

4 lbs of K2O are required to raise soil test K by 1 lb

Annual application vs. build up and maintenance

Some soils have high K fixation capacity

K f

ert

iliz

er

is c

he

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re

lati

ve

to

gra

in p

ric

es

K f

ert

iliz

er

is e

xp

en

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e

rela

tiv

e t

o g

rain

pri

ces

high

medium

low

low high

Economic response to K fertilization is most likely when soil test K

is low and K fertilizer is cheap relative to the price of corn.

What really happens to fertilizer K?

Only 20 to 60% of applied K is

taken up by crops in year 1

Highest recovery on low K soils

Available K Slowly

Available K Unavailable K

Why??

The K in KCl (muriate of potash) is near 100% plant

available but is not the only source of K (and other

cations) in the soil. Also, crop roots normally explore a

much larger volume than the zone of amendment

Soil test K, ppm

50 100 150 200 250

Yie

ld r

esp

on

se, b

u/a

cre

-40

-20

0

20

40

60

80

100

VL L O H EH(47) (19) (-2) (8) (1)

QRP

y=343-6.82x+0.034x2 if x<100

y=0 if x>100

R2=0.52 n=54

Relationship Between Soil Test K Level and Yield

Response to Starter Fertilizer in WI - 1995

www.soils.wisc.edu/extension/teachingmaterials/Wolkowski/RowPlacedFertilizer2004.ppt

Critical soil test K level, ppm

100 110 120 130

Cu

mu

lati

ve G

DD

2000

2100

2200

2300

2400

2500

Air

te

mp

era

ture

dep

art

ure

,oF

-2

-1

0

1y = 1119 - 0.84x + 0.00017x2

R2 = 0.97

19961993

1994

1995

Relationship between temperature and maximum soil test K

level where yield response occurred to starter fertilizer

www.soils.wisc.edu/extension/teachingmaterials/Wolkowski/RowPlacedFertilizer2004.ppt

Compaction affects nutrient uptake !

Potassium Affected Most • Compaction reduces porosity and

limits root growth

• Lowers soil O2 and slower

replenishment from the atmosphere

• O2 needed for root respiration and active uptake of K

• Compacted soils are often

responsive to K fertilization

www.soils.wisc.edu/extension/teachingmaterials/Wolkowski/RowPlacedFertilizer2004.ppt

Row K Effects on Corn Yield with Increasing Soil Compaction

Initial K Soil test = 102 ppm

www.soils.wisc.edu/extension/teachingmaterials/Wolkowski/RowPlacedFertilizer2004.ppt

Leaf samples consisted of the most recently fully

developed trifoliate leaves, including the petiole, collected

from 20 plants at R1 in mid- to late-July from each plot

(Yin

and V

yn,

2005)

Plant analysis for K in soybean leaves at R1 can be a useful tool for

identifying K deficiencies. Critical levels ranging from 1.2 to 1.7% K

have historically been recommended in many Corn Belt states.

It now appears that higher K levels are needed in

conservation tillage systems.

It’s well documented that alfalfa will

take-up K beyond its needs if high

levels of soil or applied K are

available. This is referred to as “luxury

consumption”.

Soils containing high

levels of magnesium and

calcium generally need

higher levels of potassium

to maintain high crop

yields due to competitive

ion effects.

High soil test K:Mg ratios

Over many years of looking at plant analysis samples, we

have seen that where the soil test ratio (lb:lb) of K:Mg is

greater than 1.5:1; many crops are likely to suffer Mg

shortages. This is often in spite of the soil having

"adequate" amounts of Mg in the soil. Where the soil test

ratio of K:Mg is between 1:1 and 1.5:1, grass crops,

including corn may be at risk of an Mg shortage. While

such an induced Mg deficiency can reduce yields, it is

possibly a bigger problem for livestock that consume the

green chop or silage. When these high soil K:Mg ratios are

combined with low to marginally sufficient Mg and/or acid

soils, the probability of Mg deficiency increases.

http://www.spectrumanalytic.com/support/library/ff/Potassium_basics.htm

Does Cation Balance Matter?

The relative concentration of potassium, calcium, magnesium,

ammonium, and other positively charged ions in the soil solution

influences their relative uptake.

Excessively high concentrations of one cation often results in

inadequate uptake of other cations.

For example, very high concentrations of calcium reduce uptake

of potassium and very high concentrations of potassium reduce

magnesium uptake.

Does Cation Balance Matter?

The relative concentration of potassium, calcium, magnesium,

ammonium, and other positively charged ions in the soil solution

influences their relative uptake.

Excessively high concentrations of one cation often results in

inadequate uptake of other cations.

For example, very high concentrations of calcium reduce uptake

of potassium and very high concentrations of potassium reduce

magnesium uptake.

Cation balance affects animal health

Grass tetany

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Material Chemical Formula

K 2 O Content %

potassium chloride KCl 60

sul-po-mag K 2 SO 4 2MgSO 4 20

potassium nitrate KNO 3 44

potassium sulfate K 2 SO 4 50

Potassium Fertilizers

“Potash” = muriate of potash = MOP guaranteed

analysis

Used in organic agriculture

Material fall06 spring07 0-0-60 207,410 143,041 0-0-62 92,880 86,821

99.1 % of material grade

94% of total

Potassium fertilizer sales in IL

569,491 tons

MOP

The chloride in MOP has

negative effects on some crops

Tobacco fertilized with MOP

produces cured leaves with muddy

and uneven color with excessive

hygroscopicity and poor burn.

MOP is salty stuff !

Potash ore is a mix of KCl, NaCl and other salts.

The KCl is concentrated using a flotation process which

skims off the surface of a fluid suspension of finely

crushed ore. This concentrate is further processed and

screened. The resulting fertilizer material is ~ 95 percent

MOP. It is reddish in color because iron impurities in the

ore are not removed in this process.

White potash is produced by a process of dissolution and

recrystallization. Potash ore is dissolved under pressure in

hot brine, and MOP is precipitated as the brine cools and

pressure reduces. The iron is removed in this process, and

the resulting MOP fertilizer is white. White MOP is generally

at least 98 percent potassium chloride.

Global K fertilizer production and consumption

Total world production = 33 million metric tons of K2O in 2007

http://minerals.usgs.gov/minerals/pubs/commodity/potash/mcs-2008-potas.pdf

Canada has the largest potash reserves

and also exports the most potash

Total global economic reserves ~ 8 billion metric tons

PotashCorp produces 23% of the world's supply of potash.

PC also controls most of the world's unused supply, and has

historically held back production to keep potash prices high.

PC is the world's largest fertilizer company #1 in potash, #3 in phosphate and #4 in nitrogen fertilizers

How much does potash cost in IL this fall?

Potash prices were up about $5.50 a ton last week in

Illinois, with the average price at $639, ranging from

$600 to $710. Illinois prices remain about $25 a ton

cheaper than Iowa, which is more in line with our forecast

models, which puts spring prices at $690 a ton.

Why does Potash track differently than Ammonia and DAP?