It is about historical development in the field of soil fertility.

1. Historical development in soil
fertility and plant nutrition

2. The period in the development of the human race
during which man began the cultivation of plants
marks the dawn of agriculture
The exact time is not known, but it was certainly
several thousands of years BC
Until then, man was nomadic in his habits

3. In all ages the growth of plants has interested
thoughtful man
The mystery of the change of an apparently
lifeless seed to a vigorous growing plant never
loses its freshness, and constitutes, indeed, no
small part of the charm of gardening
The economic problems are of vital
importance, and become more and more
urgent as time goes on and population
increases and their needs become more
complex

4. We know now the facts about the needs of
essential nutrients and other factors of plant
growth
These facts are the result of a few hundred
years of thinking and research
We thus need to know how this subject
developed historically

5. Ancient Records
• Agriculture started when man became more of a settler than of
a wanderer. Families, clans, and villages developed and the
skill of agriculture developed.
• Mesopotamia – situated between Tigris and Euphrates in Iraq-
very early civilization
• Writings dating back to 2500 BC mention the fertility of the
land
• It is recorded that the yield of Barley was 86x – 300x, i.e., for
every unit of seed planted the harvested units were 86 to 300

6. • Some 2000 years later (500 BC) – Herodotus, the Greek
historian- mentions the phenomenal yields obtained by the
inhabitants of his land
• Well developed irrigation system and soils of high fertility
• Around 300 BC- Theophrastus – richness of the Tigris
alluvium and stated that the water was allowed to remain on the
land as long as possible so that large amount of silt may be
deposited
• In time man learned that certain soils would fail to produce
satisfactory yield when cropped continuously
• The practice of adding animal and vegetable manures to the soil
to restore fertility probably developed from such observations –
but how and when is not known

7. • Augeus – a egendary king of Elis, had 3000 oxen in his stable
which was not cleaned for 30 years.
• Augeus contracted Hercules to clean the stable out and agreed to
give him 10% of the cattle in return
• Hercules is said to have accepted the task by turning the river
Alpheus through the stable
• This carried away the accumulated filth and presumably
deposited it on the adjacent land – thus enriching the land.
• In the Greek epic poem The Odyssey (Homer ,900-700 BC) the
manuring of vineyards by the father of Odysseus is mentioned.
• The manure heap, which would suggest its systematic collection
that manuring was an agricultural practice in Greece during the 9
centuries BC

8. • Xenophon (434-355 BC) observed that “the estate has gone to
ruin” because “someone didn’t know it well to manure the land”.
And again “ …. there is nothing so good as manure”
• Theoprhastus (372-287 BC) – recommended abundant
manuring of thin soils but suggested that rich soils be manured
sparingly.
• Bedding in the stall – to absorb more of the urine and bulk and
conserve it – humus value of the manure would be increased
• He suggested that plants with high nutrient requirements also
had a high water requirement
• The truck gardens and olive groves around Athens were enriched
by sewage from the city
• A canal system was used, and there is evidence of device for
regulating the flow
• It is believed that sewage was sold to farmers.

9. • The ancients also fertilized their vineyards and groves with water
that contained dissolved manures
• Manures were classified according to their richness or
concentration.
• Theophrastus listed the manures in the following order of
decreasing value:
human> swine > goat > sheep > cow > oxen > horse
• Later, Varro, an early writer on Roman Agriculture, developed a
similar list but rated bird and fowl manure as superior to human
excrement:
bird + fowl > human>swine>goat>sheep>cow>oxen>horse
• Archilocus (ca. 700 BC) mentioned about the effect that dead
bodies had on increasing the growth of crops.
• In Old Testament; in Omar Khayyam etc.

10. • The value of green manuring crops, particularly legumes, was
also soon recognised.
• Theophrastus noted that a bean crop (Vicia faba) was plowed
under by the farmers of Thessaly and Macedonia
• He observed that even when thickly sown and large amounts of
seeds were produced, the crop enriched the soil
• Xenophon (ca. 400 BC) recommended spring ploughing
because “the land is more friable then” and “ the grass turned up
is long enough at that season to serve as manure”
• Cato (234-149 BC) suggested that poor vineyard land be
interplanted with a crop of acimum. This crop was not allowed
to go to seed and ir was turned under.
• He also said that the best leguminous plant for enriching the soil
were field beans, lupines and vetch

11. • Lupine was quite popular with the ancients
• Columella listed numerous legume crops, including lupines,
vetch, lentils, chick peas, clover, and alfalfa that were satisfactory
for soil improvement
• Virgil (70-19 BC) advocated the application of legumes
• The use of what might now be called mineral fertilizers or soil
amendments was not entirely unknown to the ancients
• Theophrastus suggested the mixing of different soils as means of
“remedying defects and adding heart to the soil”
• This practice may have been beneficial from several standpoints
• The addition of fertile soils to infertile soil could lead to increased
fertility, and the practice of mixing one soil with another may
have provided better inoculation of legume seed in some fields

12. • Again, the mixing of coarse textured soils with those of fine
textured or vice versa may have caused an improvement in the
water and air relations in the soils o0f the fields so treated
• The value of marl was also recognised.
• The early dwellers of Aegina dug up marl nd applied it to their
land
• The Romans even classified the various liming materials and
recommended that one type be applied to grain and another type
to meadow
• Pliny (62-113): lime should be spread thinly on the ground and
that one treatment was “sufficient for many years, though not 50”
• Columella also recommended the spreading of marl on a gravely
soil and mixing of gravel with a dense calcareous soil
• The value of wood ashes is recorded in the Bible
• Both Xenophon and Virgil: burning of stubble to clear fields and
destroy weeds

13. • Cato: advice to the vine keeper to burn prunings on the spot and
to plough in the ashes to enrich the soil
• Pliny: use of lime from lime kilns was excellent for olive groves
• Columella: suggested the spreading of ashes or lime on lowland
soils to destroy acidity
• Theophrastus and Pliny: saltpetre (KNO3) as useful for
fertilizing plants
• Theophrastus reported the use of brine for palm trees
• Even as soil scientists of modern times have been searching for
methods of predicting the fitness of soil for production of crops,
so did the minds of the early agricultural philosophers and writers
turn to such methods
• Virgil: believed that soil that was “blackish and fat under the
deep pressed share, and whose mold is loose and crumbling is
generally best for corn”. He also wrote about soil characteristics
now known as bulk density

14. • Columella: measure the degree of acidity and salinity of soils
• Pliny: bitterness of soils might be detected by the presence of
black and underground herbs
• Many of the early writers believed that the color of the soil
was a criterion of its fertility
• The general idea was that black soils were fertile and light or
grey soils infertile
• Columella disagreed with this view point: black marsh land
soil –infertile; light colored soil from desert area –highly fertile
• He felt that such factors as structure, texture and acidity were
for better guides to an estimation of soil fertility

15. • Much of the early writings regarding soil fertility consisted
largely of descriptions of farm practices
• There seems to be little evidence of an experimental approach
to farm problems, but many of these manuscripts do reflect a
rather keen comprehension of certain of factors now known to
affect plant growth.

16. Soil fertility during the 1st
eighteenth century AD
• After the decline of Rome there were few contributions to the
development of agriculture until the publication of Opus
ruralium commodorum, a collection of local agricultural
practices, by Pietro de Crescenzi (1230-1307)
• De crescenzi is referred to by some as the founder of modern
agronomy
• He suggested an increase in the rate of manuring over that is use
at the time
• Palissy (1563) made the observation that ash content of plants
represented the material they had removed from the soil

17. • Around the beginning of the 17th
century Francis Bacon (1561-
1624) suggested that the principal nourishment of plants was
water, the main purpose of the soil was to keep the plants erect
and to protect them from heat and cold and that each plant
drew from soil a substance unique for its own particular
nourishment
• Bacon also maintained that continued production of the same
type of plant on a soil would impoverish it for that particular
species

18. • Jan Baptiste van Helmont (1577-1644) – a Flemish physician
and chemist, reported the results of an experiment which he
believed proved that water was the sole source of nutrient of
plants
• 200 lb soil + water; shielded soil to prevent dust and only rain or
d.w was used. A willow shoot weighing 5lb was planted. The
plant was grown for 5 years. After 5 years the tree that grew
weighed 169 lbs 3 ozs.
• He could account for all but 2 ozs of the 200 lbs of soil
• As he added only water – so was the sole source of nutrient
• The 2 ozs was attributed to experimental error.
• The work was done when nothing was known about mineral
nutrition and photosynthesis

19. • Van Helmont’s work was repeated several years later by Robert
Boyle (1627-1691) of England.
• He confirmed the findings of van Helmont plus one step further
• He did the chemical analyses of plant samples and stated that
plants contained salts, spirits, earth and oil, all of which were
formed from water.
• About this time, J.R. Glauber (1604-1668), a German chemist,
suggested that saltpetre and not water was the “principle of
vegetation”
• He collected the salt from soil under the pens of cattle and
argued that it must have come from the droppings of these
animals.
• He further stated that as the animals ate forage, the saltpetre
must have come originally from the plants

20. • When he applied this salt to plants and observe the large increases
in growth it produced, he was convinced that soil fertility and the
value of manure were due entirely to saltpetre
• John Mayow (1643-1679), an English chemist, supported the
viewpoint of Glauber.
• He estimated the quantities of niter in the soil at various times
during the year and found it in its greatest concentration in the
spring
• Failing to find any during the summer, he concluded that the
saltpetre had been absorbed, or sucked up, by the plants during its
rapid growth.
• About 1700, an Englishman John Woodward, grew spearmint in
samples of water he had obtained from various sources: rain water,
river water, sewage water, and sewage water plus garden mold
• He carefully recorded the weight of the plants at the beginning and
at the end of the experiment

21. • Growth of the spearmint ∞ amount of impurities in the water
• His conclusion: terrestrial matter, or earth, rather than water,
was the principle of vegetation
• Jethro Tull (1674-1741): Englishman, Oxford educated, ill
health
• Soil should be finely pulverised – soil particles were actually
ingested through openings in the plant roots – the pressure cased
by the swelling of the growing roots was thought to force this
finely divided soil into “the lacteal mouths of the roots” after
which it entered the “circulating system” of the plant
• Around 1762, John Wynn Baker, established an experimental
farm in England
• The purpose of this was the public exhibition of the results of
experiments in agriculture

22. • Arthur Young (1741-1820): did pot tests to find those
substances that would improve the yield of crops
• He grew Barley in sand and used the following materials
charcoal, train oil, poultry dung, spirits of wine, niter,
gunpowder, pitch, oyster shells and numerous other materials
• Some produced plant growth, others did not. He published his
findings in Annals of Agriculture in 46 volumes.
• Many of the agricultural writings of the 17th
and 18th
centuries
reflected the idea that plants were composed of one substance
and most workers during this period were searching this
principle of vegetation

23. • Around 1775 Francis Home said that there was not only one
principle but probably many
• He included among them air, water, earth, salts, oil, and fire in
a fixed state
• He felt that the problem of agriculture were essentially those of
nutrition of plants
• He carried out pot experiments to measure the effects of different
substances on plant growth and made chemical analyses of plant
materials
• The idea that plats contained fire in a fixed state lingered in the
minds of man for many years. There was also the belief that
organic materials or humus was taken directly by plants and that
it constituted their principal nutrient
• This idea persisted down through the years. It was difficult to
dispel because the results of chemical analyses had shown that
plants and humus contained essentially the same elements

24. • Between 1770 and 1800 work was done on the effects of
vegetation on air that was destined to revolutionise the ideas of
the function of plants in the economy of nature
• Joseph Pristley (1775) said that sprigs of mint purified air –
plants, instead of affecting the air in the same manner with
animal respiration, reverse the effects of breathing, and tends to
keep the atmosphere pure and wholesome.
• He had not yet discovered O2, so he could not give precision to
his discovery
• Later on, when he discovered O2 and learned how to estimate it,
he unfortunately failed to confirm his earlier results as he
overlooked the necessity of light
• He was therefore unable to answer Scheele, who had insisted that
plants, like animals, vitiate the air

25. • Jan Ingenhousz (1730-1799) said that purification of air goes
on in light only, while vitiation takes place in the darkness
• Jean Senebier (1742-1809), a Swiss natural philosopher and
historian, had also arrived at the same result
• He also studied the converse problem – the effect of air on
plants
• In 1782 he stated that the increased weight in the van
Helmont’s willow tree was the result of fixed air

26. Progress during the 19th
century
• Theodore de Saussure (1804) attacked two problems of
Senebier – the effect of air on plants and the origin of salts in
plants
• He grew plants in air or in known mixtures of air and CO2 and
measured the gas changes and the changes in the plant
• De Saussure was able to demonstrate that plants absorbed O2 and
liberated CO2
• In addition, he found that plants would absorb CO2with the
release of O2 in the presence of light
• If, however, plants were kept in an environment free of CO2, they
died
• De Saussure concluded that the soil furnishes only a small
fraction of the nutrients needed by plants, but he demonstrated
that it does supply both ash and nitrogen

27. • De Saussure effectively dispelled the idea that potash is
spontaneously generated by plants and stated further that the
plant roots do not behave as a mere filter. Rather the
membranes are relatively permeable, allowing for a more rapid
entrance of water than of salts
• He also showed the differential absorption of salts and the
inconsistency of plant composition, which varies with the
nature of the soil and the age of the plant
• De Saussure’s conclusion that the C contained by plants was
derived from the air did not meet with immediate acceptance by
his colleagues
• Sir Humphrey Davy in 1813, stated that some plants may have
received their C from the air but major portion of it was taken
through the roots
• He recommended oil as fertilizer because of its high C and H
content

28. • The middle of the 19th
to the beginning of the 20th
century was a
time during which much progress was made in the understanding
of plant nutrition and crop fertilization
• Famous among the people during this period was Jean Baptiste
Boussingault (1802-1882) – a widely travelled French chemist
• Established a farm in Alsace on which he carried out field plot
experiments
• He employed the careful techniques of de Saussure in weighing
and analyzing the manures he added to his plots and the crops he
harvested
• He maintained a balance sheet that showed how much of the
various plant nutrient element came from rain, soil, and air
• He analyzed the composition of his crop during various stages of
growth
• He determined that he best rotation was that which produced the
largest amound of O.M. in addition to that added in the manure

29. • Boussingault is considered by some as the father of the field-plot
method of experimentation
• Many of the agricultural scientists of this period recognised the
value of de Saussure’s observations
• However, there were many adherents to the old humus theory
• It was such a natural theory that it was difficult to dispel
• Many must have felt then, as some do today, that the decay of
plant and animal materials give rise to products that are best
suited for the nutrition of growing plants
• The humus myth was very effectively disposed of by the
German chemist Justus von Leibig (1803-1873).
• Since then, only a few scientists have dared to suggest that the C
contained in plants comes from any source other than CO2.
• Leibig made the following statement:

30. • Most of the carbon in plants comes from the CO2 of the
atmosphere
• H2 and O2 comes from H2O
• The alkaline metals are needed for the neutralization of acids
formed by plants as a result of their metabolic activities
• Phosphates are necessary for seed formation
• Plants absorb anything indiscriminately from the soil but excrete
from their roots those materials that are nonessential
• Acetic acid is excreted by roots
• NH4
+
form of N is the one absorbed and plants might obtain this
compound from soil, manure, or air
• Not all of Leibig’s ideas were of course not correct
• Leibig firmly believed that by analysing the plant and studying
the elements contained one could formulate a set of fertilizer
recommendations based on these analyses

31. • It was also his opinion that the growth of plants was
proportional to the amount of mineral substances available in
the fertilizer
• He eventually developed the law of the minimum ; the growth
of plants is limited by the plant nutrient element present in the
smallest quantity, all others being present in adequate
amounts
• Leibig manufactured a fertilizer on his ideas of plant nutrition
• The formulation of the mixture was perfectly sound
• However, he made the mistake of fusing the phosphate and
potash salts with lime, as result the fgertilizer was a complete
failure
• Leibig is considerd as the father of agricuktural chemistry

32. • J.B.Lawes and J.H.Gibert established in 1843 n agricultural
esperiment station at Rothamsted, Herpenden, Herts, England
• Work here was carried out along the same line as tht carried out
earlier by Boussingault in France
• Lawes and Gilbert did not believe that all of the maxims set down by
Leibig were correct
• 12 years after the founding of the station they settled the folowing
points:
1. Crops require both P and K, but the composition of the plant ash is no
measurement of the amounts of these constituents required by the
plant
2. Nonlegume crops require a supply of nitrogen. Without this element,
no growth will be obtained, regardless of the quantities of P and K
present
3. Nitrate and ammonium salts being lmost equally good. The amount of
ammonium nitrogen obtainable from atmosphere is insufficient for the
needs of crops

33. 4. Leguminous crops behave abnormally
5. Soil fertility could be maintained for some years by means of chemical
fertilizers
6. The beneficial effect of fallow lies in the increase in the availabilityof
N compounds in soil
• The water cultures of Knop (1861) and other plant physiologists
showed conclusively that K, Mg, Ca, Fe, P, along with S, C, H, N
and O are all necessary for plant life
• For a long time, farmers were reluctant to believe that fertility could
be maintained by the use of chemical fertilizers alone
• The early work at Rothamsted proved conclusively that it could be
done

34. • In 1852, Thomas Way in England first demonstrated the
phenomenon of cation exchange from the observation that a Yorkshire
farmer was able to reduce ammonia loss from manure by the addition
of soil. However, its tremendous significance was not immediately
recognised.
• George Ville (during 1867 and 1874-75)- a Frenchman of
Viencennes, recognised the value of some of the early results from the
Rothamsted experiments
• He maintained that the use of chemical fertilizers was the only method
of supporting soil fertility
• He made recommendations for the fertilization of crops based on the
results of field trials
• He drew up a simple scheme of plot tests that could be used by
farmers to determine for themselves just what fertilizers were needed
for their crops
• Ville’s view that chemical fertilizers were always better and cheaper
than dung is too narrow and did not survive

35. • The problem of soil and plant nitrogen remained unsolved
• Several workers had observed the unusual behaviour of legumes
• In some instances they grew well in the absence of added N, whereas
in others no growth was obtained
• Nonlegumes, on the other hand always failed to grow when there was
insufficient nitrogen in the soil
• In 1878 some light was thrown on the confusion by two French
bacteriologists – Thodore Schloessing and Alfred Műntz
• They purified sewage water by passing it through a filter made of
sand and liume stone – analysed the filtrate periodically for 28 days
• Only NH4 – N was detected during this period
• At the end of this time NO3 began to appear in the filtrate
• They observed that the production of NO3 could be stopped by adding
chloroform and that it could be started again by adding a little fresh
sewage water
• They concluded that nitrification was the result of bacterial action

36. • Robert Warrington during 1878-1891, applied the results of
these experiments to soil processes
• He showed that nitrification could be stopped by CS2 and
chloroform and that it could be started again by adding a small
amount of unsterilized soil
• He also demonstrated that the reaction was a two step
phenomenon, the NH3 first being converted to NO2 and then to NO3
• He, however, failed to isolate the organisms by using gelatin
method
• The organism was later isolated by S. Winogradsky in 1890 on
silica gel plate
• As to the erratic behaviour of legumes with respect to N, the two
Germans, Hellriegel and Wifarth in 1866 concluded that bacteria
must be present in the roots of legume roots

37. • These organisms were believed to assimilate gaseous N from the
atmosphere and to convert it to form that could be used by higher
plants
• The organism was isolated by M.W. Beijerinck (1890) and
named it Bacillus radicicola, later named as rhizobium and now
known as Bradyrhizobium
• The general conclusion that bacteria are the real makers of plant
food in soil, and are, therefore, essential to the growth of all
plants, was developed by E. Wollny and M. Berthelott (1884)
• It was supposed to be proved by E.Laurent’s (1886) experiment
• Further investigation of soil problems has shown that they are
more complex than was first supposed
• Soils can no longer satisfactorily be divided into a few simple
groups: sands, clays, loams etc., according to their particle size;
nor an alteration be confined to the surface layer

38. • It is necessary to take their history
• Soil properties as enunciated by the Russian investigator V V
Dokuchaev (1883) are dependent on factors like climate,
vegetation besides parent materials.
• This ushered the study of soil as a living entity and other aspects
of soil uses
• Thus we study any soil on pedologic and edaphologic aspects
• The advancement soil studies in the 20th
and 21st
centuries have
been tremendous
• Soil chemical processes, physical processes, biochemical and
microbiological are now studied in both destructive as well as
non-destructive methods
• Soils are now classed as per their suitability to specificcrop
production or other uses