Welcome to Soil Fertility

and Plant Nutrition

AGRN 378

Did the ancient

Egyptians know

anything about soil

fertility?

Ancient Egyptian murals

show lots of agricultural

practices - tillage, planting,

irrigation and harvesting but

no fertilization

http://www.artsci.wustl.edu/~anthro/courses/306/Nile%20Delta.jpg http://lexicorient.com/e.o/atlas/maps/nile.gif

Why did

Greek

historian

Herodotus

write

Egypt is

truly a gift

of the Nile?

4-5 million

people during

the New

Kingdom

Most of Egypt

is desert !

Nile

High Aswan Dam

constructed

beginning in 1960

6 T

RIL

LIO

N C

FT

1.2

TRILLION

CFT

Ho

ove

r

Dam

Hig

h A

sw

an

Dam

Each year ~ 120 million tons of sediment accumulates

behind the dam containing ~ 10,000 tons of biologically

available P and N !

Shrimp harvest along Egyptian Coast

Mediterranean fisheries collapsed after the

construction of the High Aswan Dam

Nixon, 2003. Replacing the Nile: Are Anthropogenic Nutrients Providing the Fertility Once Brought to the

Mediterranean by a Great River? Ambio. Volume 32, Issue 1 (February 2003)

So…why are

the fisheries

recovering?

Shrimp harvest along Egyptian Coast

Nixon, 2003. Replacing the Nile: Are Anthropogenic Nutrients Providing the Fertility Once Brought to the

Mediterranean by a Great River? Ambio. Volume 32, Issue 1 (February 2003)

So…why are the fisheries recovering?

SEWAGE from Cairo

Aquatic ecosystems

in the Mediterranean

are nutrient limited

unlike the Gulf of

Mexico

Roman art also reveals a

lot about their agriculture.

In addition to Saturn and Ceres (Roman

god and goddess of Agriculture), the

Romans had a god of manure named

Stercutius who was worshiped by old

women and children.

Stercutius

A number of Roman authors (e.g., Cato, Columella, Pliny the Elder)

wrote detailed textbooks on agriculture that described the use of

animal manures, green manures and crop rotations to improve soil

productivity. These books were considered important sources of

information about agriculture for over a thousand years.

Pliny the Elder (AD 23-79) classified animal

manures with respect to their advantages

and disadvantages of most animal manures

and recommended the use of green

manures. "It is universally agreed by all

writers that there is nothing more beneficial

than to turn up a crop of lupines, before they

have podded, either with the plough or the

fork, or else to cut them and bury them in

heaps at the roots of trees and vines."

Blue lupines

The earliest records of soil improvement using green

manures are from the Chou dynasty (~1000 BC) in

China. Later (500 BC), Tsi gave the following advice:

“Green manures are planted in the 5th or 6th month,

and plowed under in the 7th or 8th month... Their

fertilizing value is as good as silkworm excrement and

well-rotted farm manure"

China has had more than 50 million people for more than 2000

years and currently has more than 300 million farmers!

“ We desired to learn how it is

possible, after twenty and

perhaps thirty or even forty

centuries, for their soils to be

made to produce sufficiently for

the maintenance of such dense

populations.. “

FH King, 1911

Fertilizing with night soil

http://library.thinkquest.org/C006206F/images/images/pint5.jpg

Chinampas Agriculture

in Central America

http://www.icarito.cl/vgn/images/portal/FOTO042005/221466640lamina-chinampas.jpg

http://kyapa.tripod.com/agengineering/drainage-lowland/veracruzbuildingchinampas.jpg

Building Chinampas

http://kyapa.tripod.com/agengineering/drainage-lowland/camell-colombia.jpg

Chinampas in the Momposina lowland region of Columbia

In 1240, Roman agricultural literature was summarized by Crescentius.

http://www.abbeville.com/Products/InteriorImages/0896599191Interiors.htm

Bernard Palissy (1510-1589)

Ceramicist and hydraulic

engineer

Far ahead of his time, Palissy

wrote: ”Manure is carried to the

field for the purpose of restoring

to the latter a part of what had

been removed... Proceeding

thus you will restore to the soil

the same substances that have

been removed by previous

crops and which following crops

will regain to their advantage."

JB van Helmont (1577-1644)

Dutch physician and Chemist

What is the

“principle of

vegetation”?

JB van Helmont (1577-1644)

Dutch physician and Chemist

What is the

“principle of

vegetation”?

What do

plants

eat?

Van Helmont’s

pot experiment

5 lbs

of

plant

200 lbs

of soil

only water

was added

169 lbs

of plant

199 lbs,

14oz of soil

T=0 T= 5 yrs

Van Helmont also performed

experiments that involved combusting

charcoal and reported that 62 lbs of

charcoal produced 1 lb of ash.

He wrote that the other 61 lbs consisted

of the "spirit of the wood," which he

called "gas".

Philosophical Transactions Volume 21 (1699 !)

John Woodward discovered

that the growth of spearmint

cuttings was positively

related to the amount of

dissolved solids in water

How many of you have heard of the band “Jethro Tull”?

Jethro Tull, 1731

Jethro Tull invented the grain drill and many

complementary technologies that resulted in

large increases in grain yields during the

18th century.

George Washington took

great pains to inform himself

about any subject in which

he was interested.

He corresponded with Arthur

Young, Britain’s leading

agriculturalist in the post-

Revolutionary period and

ordered the latest British

books about new agricultural

practices.

Among Washington’s papers

are detailed notes taken as

he studied Jethro Tull’s

Horse Hoeing Husbandry.

“All sorts of dung and

compost contain some

matter, which, when mixt with

the soil, ferments therein; and

by such ferment dissolves,

crumbles, and divides the

earth very much; This is the

chief, and almost only use of

dung...

The value of dung is not to

nourish, but to dissolve, i.e.,

divide the terrestrial matter,

which affords nourishment to

the mouths of vegetable

roots.”

Jethro Tull, 1731

Tull’s theory of

plant nutrition

This article starts with a brief review of

theories about plant nutrition and the

importance of humus prior to the mid- 19th

century. It then shows how the “Humus

Theory” developed by Thaer allowed him to

establish a quantitative system of evaluating

cropping system sustainability.

Similar to animals, plants must feed upon

organic substances that are similar to

them in composition.

Soil organic matter aka humus, is the

chief nutrient for plants and the primary

source of soil fertility.

Roots absorb humus and transform it

into plant substance, by combining it

with water.

The

humus

theory

In the early 1800s, Swiss chemist and plant physiologist

Nicolas-Théodore De Saussure rejected most of the

principle of vegetation concepts of his predecessors

and arrived at many ground breaking conclusions:

1) soil, not air, supplies plants with N

2) roots are active and selective absorbers of water and salts

3) plants only absorb CO2 and release O2 when exposed to

sunlight

4) All plant tissues including seeds and roots consume O2 and

give off CO2

but did not fully reject the humus theory

Answers to the reading questions

should be submitted using WO

before the start of Friday’s class

Reading questions

1) The article includes an interesting quote from Jethro Tull:

“The chief art of the husbandman is to feed the plants to best advantage; but,

how shall he do that, unless he knows what is their food?”

Identify the contrasting views about plant nutrition contained in the article. Be

sure to mention the proponents of each view.

2) Discuss de Saussure’s relationship with his father. Has anyone in your life

helped to spark or encourage your interest in the Agricultural Sciences?

Explain.

3) De Saussure made many impressive discoveries about plant respiration and

nutrition. Briefly discuss 3 discoveries that you think were particularly

interesting.

4a) Calculate how much a typical corn seed weighs in grams (1 lb = 454 g).

Hint: look up the weight of a bushel of corn and # of seeds in a bushel of corn.

4b) Estimate the total weight of a mature corn plant in grams.

Assume the following: corn population = 30,000 plants/ac, yield = 200 bu/ac,

weight of grain = weight of stover = weight of roots

4c) Calculate how much the corn seed’s weight multiplied during a full season of

growth.

SHOW YOUR WORK!!!!

1/100 of an oz

grain

+

cob

+

stalk

+

leaves

+

roots

_____

> 1 lb

How is this possible??

“ The conclusion should have

been reached long ago that

humus is not such an important

substance as we have been led to

believe, and that the current

doctrine of humus is exceedingly

full of contradictions.”

Carl Sprengel 1838

Rejection of the humus theory

Justus von Liebig

was a pioneering German

chemist who wrote and lectured

extensively about the mineral

nutrition of plants. As the first

professor to use the laboratory

method of teaching chemistry,

he is regarded as one of the

greatest chemistry educators of

all time.

He was held in such high

esteem that few dared to

question his pronouncements

about mineral nutrition.

Justus von Liebig (1803 -1873)

Justus von Liebig (1803 -1873)

Law of

the

Minimum

Liebig did not actually introduce the

Law of the Minimum but deserves

credit for popularizing the concept

Liebig

recommended

a “check book”

approach to

fertilization

What is liberated and what is left behind

when plant biomass is burned ?

Metal oxides

(K, Ca, Mg, P, Fe…)

Non-metal oxides

(C, N, H and S)

Liebig believed

that the ash

generated when

a crop is burned

contained the

optimal blend of

nutrients for

fertilizing the

crop

Liebig wrote: ‘Agricultural crops receive quite sufficient

nitrogen from the atmosphere ...’

Some of Liebig’s theories were not

supported by experimental evidence but

few were willing to publicly question them.

Sir John Lawes, a British contemporary of Liebig was bold

enough to declare: ‘There can not be a more

erroneous opinion than this.’

http://nolimits.nmw.ac.uk/IEN/rotham.jpg

Rothamsted

Experiment

Station

Lawes and Gilbert founded the first agricultural

experiment station

Sir John Lawes Sir Henry Gilbert

• Started in 1843

• Continuous wheat

for more than 160 years

• The oldest agricultural field

experiment in the world.

Broadbalk

experiment

J.B. LAWE'S PATENT MANURES, composed

of Super Phosphate of Lime, Phosphate of Ammonia, Silicate of Potass, &c., are now

for sale at his Factory, Deptford-creek, London,

price 4s. 6d. per bushel.These substances can

be had seperately; the Super Phosphate of Lime alone is recommended for fixing the

Ammonia of Dung-heaps, Cesspools, Gas

Liquor, &c. Price 4s. 6d. per bushel

From : The Gardeners Chronic le

July 1, 1843 page 442

JB Lawes opened one of the first

fertilizer factories in Europe and

needed to convince farmers that they

should use his fertilizers

Broadbalk demonstrated the value

of N and P fertilizer and that

manure was not necessary to

produce high crop yields

the plots receiving both manure and

fertilizer often produced the

highest yields

however

0

1

2

3

4

5

6

7

8

9

10

1850 1875 1900 1925 1950 1975 2000

Wh

ea

t g

rain

yie

ld (

t/h

a)

Unmanured, continuous wheat

Continuous wheat:

FYM PK+144 kg N

1st wheat in rotation:

FYM+96 kg N Best NPK

Introduction of: liming fungicides

fallowing herbicides

Broadbalk grain yields, selected treatments

Why have the

yields been

leveling off?

The Broadbalk archive

currently contains over

200,000 bottles of hay, grain

and soil

Why do they keep

all these old samples ?

The Broadbalk archive

currently contains over

200,000 bottles of hay, grain

and soil

Why do they keep

all these old samples ?

Old samples provide answers

to new questions !

Morrow Plots - started in 1876 at the U of Illinois

- oldest agronomic experiment in the US

Cyril Hopkins (right), head of the U of Illinois Department of Agronomy, and James H.Pettit (left),

assistant in Soil Analysis at the Ag Experiment Station, collect soil samples from the Morrow Plots

" ... it is not the land itself that

constitutes the farmer's wealth, but it is

in the constituents of the soil, which

serve for the nutrition of plants, that

this wealth truly consists."

“The farmer should be as familiar with

the names of the ten essential elements

of plant food as he is with the names of

his ten nearest neighbors”

“In recent years, Whitney and Cameron have revived the theory of toxic

excreta from plant roots, in support of a more radical theory announced by

them, to the effect that soils do not wear out or become depleted by cultivation

or cropping.

While this theory is advanced with no adequate foundation and in direct

opposition to practical experience and to so many facts of mathematics,

chemistry, and geology, that it is in itself quite unworthy of further

consideration, the fact is that it has been promoted by Professor Whitney as

Chief of the United States Bureau of Soils, and by Doctor Cameron as the

chief chemist of the same Bureau; and, consequently, it cannot be ignored”

Soil Fertility and Permanent Agriculture – Cyril G. Hopkins, 1910

Legumes can fix their own N *if* they have the appropriate bacteria

Rhizobia bacteria first

isolated in mid 1880s

Morrow plots today – 3 of the 10 original plots remain

Impact of nutrients and rotation on SOM

http://www.cropsci.uiuc.edu/research/rdc/urbana/morrow.cfm

MLP = Manure, lime and phosphorus added

Long rotations with fertilization retained more OM but

all rotations (with and without fertilization) led to loss of OM

19th century farmers had limited

opportunities to purchase

nutrients. Some used guano

imported from South America.

Large yield responses were

reported for a wide range of

crops after applications of

guano.

Guano is a concentrated

source of N (~ 12 %) and P2O5

(~ 12 %), with much higher

analyses than most organic

fertilizers.

Guano was mined intensively off the west coast of S. America

during the mid-to late 1800s. During the peak years of guano

mining, Great Britain imported over 150,000 tons annually.

PERU

Mountain of guano

off the coast of Peru

Fritz Haber – a man with many faces

Laboratory apparatus

designed by Fritz

Haber for producing

NH3 from H2 and N2.

The catalytic process

took place in the large

cylinder on the left.

Founded in 1865, BASF is the world's largest chemical

company, ahead of Dow and DuPont, ~ 100,000 employees,

>80 billion in sales in 2007.

Karl Bosch worked for BASF and developed the technology

for upscaling Haber’s method of NH3 production.

Nitrates and ammonia made up 59 percent of BASF sales in

1919.

~ 130 gallons of diesel fuel per ton of NH3

~ 185 GDF/ton NH3

~ 300 GDF/ton NH3

Industrial N fixation is very energy intensive

Fig. 6.12 in Smil (2001)

Large

improvements

in energy

efficiency

were made

during the 20th

century.

> 700 GDF/ton NH3

GDF = gallon of diesel fuel

What happened ~ 7 years ago ?

Fertilizer application in the US since 1850

Total

N

K2O

P2O5

What

happened

during the

80s??

Farmers cut way back

on their fertilizer

purchases during the

“Farm Crisis”

lbs of

nutrient

applied

per

bushel

produced

What are the long term consequences of ratios > 1?

http://www.afa.com.eg/uploads/papers/2011/files/3_fixen_paper.pdf

Deficit spending is drawing down

soil test P levels in the Midwest

http://www.nytimes.com/imagepages/2008/04/30/business/20080430_FERTILIZER_GRAPHIC.html

What happened in 1989?

Worldwide Growth In Fertilizer Use

http://www.earth-policy.org/Updates/2005/Update48_data.htm

http://www.agecon.purdue.edu/topfarmer/newsletter/TFCW8_2008.pdf

Fertilizer prices began spiraling upward in 2007

Why??

World fertilizer prices collapsed in the fall of 2008

So

where

are

prices

today?

http://www.growthstockwire.com/images/charts/2009/feb/20090225_chart_a.gif

Why??

http://farmfutures.com/mdfm/Faress1/author/252/2012/8/WFertR082012.pdf

http://farmfutures.com/mdfm/Faress1/author/252/2012/8/WFertR082012.pdf