The history of fertilisation is closely linked to the way humans have interpreted soil fertility and plant nutrition. For centuries, agronomic experience associated productivity with the presence of crop residues, manure and soils considered to be “rich”. In the 19th century, chemistry clarified the role of mineral nutrients. Today, soil science integrates chemical, physical and biological components into the concept of fertility, providing the basis for modern fertilisation strategies. This evolution explains why modern soil fertility management cannot be reduced to the simple application of nutrients, but must also consider the quantity and quality of organic matter, soil microbial activity, its physical characteristics (structure first and foremost) and, more generally, the resilience of the soil-plant system.
2 October 2026
Key milestones in the history of fertilisation
Indice
- From ancient times to the end of the 18th century: how the concept of fertility emerged
- The modern turning point: Liebig and mineral fertilisation
- Lawes and Gilbert: the Rothamsted experiments
- From chemistry to microbiology: microorganisms and soil fertility
- The modern era: the renewed importance of organic matter
- The first synthetic nitrogen fertilisers
- Fertilisation today: organic, mineral and organo-mineral fertilisers
- Soil always at the centre
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From ancient times to the end of the 18th century: how the concept of fertility emerged
Agriculture in general and, in particular, the topic of soil fertility, its maintenance and restoration have been addressed by numerous authors from ancient times to the present day.
The ancient Romans “read” fertility through practical observations: soil colour and texture, crop response to rotations and the use of animal manure… Authors such as Cato, Varro and Columella distinguished between different types of manure, described how they should be stored and recommended applying plant and animal materials to cultivated fields. There was no theory of plant nutrition, but the operational principle of nutrient replenishment was already clear: in cultivated soil, what plants removed during their production cycle had to be replenished.
At the beginning of the 14th century, Pietro De’ Crescenzi brought together classical knowledge and practical experience in his Opus ruralium commodorum. In this work, he systematically organised cultivation and farm management techniques, consolidating the ancient tradition of practices based on the use of manure, crop rotations and soil tillage.
Bernard Palissy (16th century) focused on the importance of mineral salts in plant nutrition.
The experiments conducted by John Woodward at the beginning of the 18th century showed that plants whose roots were immersed in water containing soil material grew better than those whose roots were immersed in plain water, reinforcing the idea that soil provided components essential for crop development.
Between the late 17th and early 18th centuries, Jethro Tull placed great importance on fine and repeated soil tillage, believing that roots used soil particles. Although his hypothesis was incorrect, the seed drill developed by this agronomist and experimenter, together with row cultivation, nevertheless contributed to the development of more modern agriculture.
In the mid-18th century, Francis Home, in his book The principles of agriculture and vegetation, reported the results of his experiments with different fertilising materials and, at around the same time, Johan Gottschalk Wallerius, Agriculturae fundamenta chemica, contributed to distinguishing the function of humus from that of mineral substances.
By the end of the 18th century, the picture was still incomplete, but the question had now been formulated scientifically: what substances actually nourish the plant?
The modern turning point: Liebig and mineral fertilisation
In the first half of the 19th century, Justus von Liebig introduced the concept of chemical balance into plant nutrition. In Die organische Chemie in ihrer Anwendung auf Agricultur und Physiologie (1840), he challenged the idea that humus was the sole source of plant nutrition and placed mineral elements absorbed from the soil at the centre of his theory. This provided the theoretical basis for mineral fertilisation: supplying cultivated plants, in chemical forms that can be directly absorbed, with the elements essential for production.
Liebig is also associated with the law of the minimum, previously formulated by Carl Sprengel and made famous by the German chemist: growth is limited by the nutrient available in the lowest quantity relative to plant requirements, rather than by the total amount of resources. The principle remains fundamental to nutritional diagnosis, provided that interactions between nutrients, water, pH, roots and soil biology are taken into account. More controversial was the so-called “Liebig’s patent manure”, a mineral fertiliser prepared in poorly soluble forms to reduce losses of nutrients not used by plants: the product’s agronomic performance proved disappointing. The episode demonstrated that a theoretically complete formulation is not effective if nutrients do not become available when the crop requires them.
Lawes and Gilbert: the Rothamsted experiments
Around the middle of the 19th century, John Bennet Lawes and Joseph Henry Gilbert began long-term field trials at Rothamsted, in England, on wheat and other crops. They compared unfertilised plots with plots fertilised using manure, individual mineral nutrients, combinations of mineral fertilisers, and combinations of mineral fertilisers and manure. The results experimentally demonstrated that high yields required adequate nutrient inputs, including readily available Nitrogen (which contradicted Liebig’s claim that crops could meet their entire Nitrogen requirement through the fixation of atmospheric Nitrogen), and that mineral fertilisation can sustain productivity when properly balanced, while manure simultaneously influences nutrition, organic carbon, soil structure and water-holding capacity. These findings should not be interpreted as a formal opposition between mineral and organic fertilisation, but rather as evidence that satisfactory crop yields and soil health need to be assessed over long time scales in order to draw sound conclusions.
From chemistry to microbiology: microorganisms and soil fertility
In the second half of the 19th century, it became clear that many nutrient transformations were not merely spontaneous chemical reactions. Maxime Berthelot studied the fixation of atmospheric Nitrogen in the soil and helped shift attention towards the activity of microorganisms. Research into root nodules and symbiotic bacteria subsequently established that legumes can acquire Nitrogen through symbiosis with nitrogen-fixing microorganisms. At the same time, Ewald Wollny developed an experimental approach to soil physics and biology, studying the effects of organic matter on water retention, temperature and soil aeration, as well as the effects of these physical properties on productivity, also in relation to the decomposition of organic matter by the microbiota.
As is well known today, modern microbiology views soil as a highly biodiverse habitat in which different types of microorganisms mineralise plant and animal residues, temporarily immobilise nutrients, fix Nitrogen, perform nitrification and denitrification, solubilise Phosphorus and interact with roots. The rhizosphere is therefore a crucial biological interface.
The modern era: the renewed importance of organic matter
In the 20th century, the widespread availability of industrial fertilisers increased yields and supported food security. However, in many intensive systems, crop specialisation (monoculture), the absence of crop rotations, reduced organic matter inputs, frequent tillage and the effects of climate change have contributed to the depletion of organic Carbon. Added to this are erosion, compaction, local salinisation and loss of biodiversity.
The renewed importance of organic matter in fertilisation does not imply a return to the outdated concept of humus as a universal source of plant nutrition. Rather, it requires an in-depth understanding of its multiple functions: aggregation and structural stability, porosity, exchange capacity, nutrient storage and cycling, water retention, stress mitigation and support for microbial networks.
The first synthetic nitrogen fertilisers
At the beginning of the 20th century, the company now known as Yara International (founded at the time as Norsk Hydro) achieved the world’s first industrial production of synthetic nitrogen fertilisers, addressing the severe nutrient shortage that threatened global agriculture.
Scientist Kristian Birkeland and industrialist Sam Eyde, founders of Norsk Hydro, developed a method for the direct fixation of atmospheric nitrogen using an extremely high-temperature electric arc furnace, which made it possible to combine Nitrogen and Oxygen from the air, generating nitrogen oxides that were subsequently converted into nitric acid and, finally, Calcium nitrate (the first commercial mineral Nitrogen fertiliser, named Norgessalpeter). The Birkeland-Eyde process required an enormous amount of electricity and, for this reason, Norsk Hydro chose Norway as its base, with its abundant water resources, building major hydroelectric power plants at Notodden and Rjukan. This marked the beginning of the transition from the use of finite natural resources (such as guano or Chilean nitrate) to large-scale chemical and synthetic production.
Although the Birkeland-Eyde process was innovative, it was energy-inefficient compared with subsequent technologies. During the 20th century, the company first implemented water electrolysis and later converted its plants to the more efficient Haber-Bosch process and the use of natural gas, maintaining its global leadership in nitrogen chemistry.
Fertilisation today: organic, mineral and organo-mineral fertilisers
Modern fertilisation must start from soil analyses, crop requirements, production targets and nutrient balances. Mineral fertilisation retains an essential role when a deficiency needs to be corrected precisely or, more generally, when the immediate availability of one or more nutrients is required. However, mineral inputs alone cannot replace the structural and biological functions of the organic matrix. Soil improvers and organic fertilisers provide Carbon and nutrients that are released over an extended period; their effectiveness depends on the origin and quality of the organic matrix, the application rate and the method of application.
Organo-mineral fertilisers combine an organic matrix with mineral nutrients. When properly formulated and applied, they can combine relatively rapid nutrient availability with more gradual release, improve nutrient placement and contribute to carbon inputs.
Soil always at the centre
The history of fertilisation shows a progressive broadening of the concept of fertility. Today, the challenge is to produce while reducing the depletion of soil capital and promoting its regeneration. There is no absolute opposition between organic and mineral fertilisation: what is needed is to rebuild efficient cycles, increase resilience and preserve soil fertility over the long term.
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