Introduction
In its modern conception, botany is the branch of biology dedicated to the study of the plant kingdom. During the early modern period, it evolved beyond its traditional role as an ancillary discipline of medicine and pharmacy, ultimately asserting its epistemic autonomy in the nineteenth century. However, botany maintained a complex relationship with the agricultural sector, as for a long time, it provided the theoretical foundations necessary for experimenting with the economic use of plant species.Footnote 1 One of the primary objectives of botany, for example, was the classification of plant species within a given territory, considering geomorphological, environmental, and climatic factors in the compilation of increasingly refined florae. Furthermore, the branch of botany now known as phytopathology developed during the modern period, benefiting from increasingly sophisticated technologies, particularly microscopes. As ‘economic botany’, this discipline also played a crucial role in modifying rural ecosystems, proposing the introduction of new species and cultivation techniques that could contribute not only to agriculture but also to forestry and the production of raw materials for manufacturing industries.Footnote 2
Over time, commodities of plant origin have constituted both scientific and economic challenges, some of which pertained to difficulties in supply or long-distance trade. The most emblematic examples include food commodities (such as cereals, sweeteners, tea, and coffee) and those linked to textile production (such as dyes, fibres, and oils). For this reason, in the eighteenth and nineteenth centuries, governments and experts were generally faced with two alternatives: either acclimatizing new plant species or working with native or already acclimatized species to identify substitutes for imported products. In both cases, the primary objective was to reduce dependence on imports. A classic example is the extensive studies and experiments conducted during the Napoleonic period to identify alternatives to British cane sugar or to acclimatize sugarcane itself. Napoleonic policies, supported by a network of experts, drew upon earlier experiences and left an important legacy to nineteenth-century agriculture: the emergence of beet sugar as a new commodity.Footnote 3
Moreover, in an agricultural economy such as that characterizing eighteenth-century Europe – already integrated into global trade and the exchange of botanical specimens – new crops and improved yields were fundamental economic issues. The analysis of the natural economy was a key concept in eighteenth-century economic thought. While an emerging perspective suggested that humans could conquer and control the natural world, the economy at the time remained largely governed by the laws of nature.Footnote 4 However, a gradual shift occurred in nineteenth-century economic thought and political-economic strategies, which increasingly sought to emancipate human activity from the constraints imposed by the natural environment.Footnote 5
It is evident that these issues are deeply intertwined with the history of ecology and environmental studies, as the acclimatization of new species and the enhancement of local crops to produce surrogates had direct consequences on biodiversity and biomass balance. Indeed, research and experiments in economic botany were not limited to university gardens, academies, and scientific societies but actively shaped both the environment and rural societies. Moreover, local populations received and reinterpreted state directives and scientific-technical innovations in various ways.Footnote 6
At the same time, the circulation of ideas, publications, and plant specimens significantly increased during the eighteenth and nineteenth centuries, benefiting naturalists, agriculturists, and landowners. By communicating with one another through direct correspondence, the exchange of written works, and the growing circulation of periodicals, they shared ideas and opinions, compared economic development strategies, and adapted foreign economic models to local contexts.Footnote 7
The debate and management of old and new crops are, therefore, an interesting example for understanding how political economy and the development of science and technology interact with rural society. From this perspective, however, such a fertile, economically active, and demographically rich region, which was the setting for key innovations like the Po Valley in the eighteenth and nineteenth centuries, still lacks studies that analyse this dimension in a detailed and articulated manner. This article aims to provide an initial study, focusing on the acclimatization of plants in the Po Valley, which provides an excellent example for examining the interplay between botany and the rural world. This analysis contributes to the historiographical debate on the evolution of rural biodiversity. The analysis of land use in Northern Italian plains and its transformations over the centuries has its roots in seminal studies,Footnote 8 followed by other important research addressing these topics from a variety of interpretative perspectives.Footnote 9
At the same time, our article seeks to enhance the study of relations between individuals – both from the scholarly community and rural society, which remains an underexplored aspect. To achieve this, it focuses on an American plant species acclimatized in the Po Valley, which became the subject of experimentation and debate in the eighteenth and nineteenth centuries: the potato (Solanum tuberosum L.), analysed from different perspectives. Scholars such as Andrew F. Smith and Rebecca Earle have studied the diffusion of the potato on a global scale over the centuries, considering the cultural and dietary implications of this phenomenon. Melchior Jakubowski’s studies have offered an insightful analysis of the introduction of potato cultivation and consumption in Eastern Europe, examining the social actors involved and discussing the role of institutions.Footnote 10 David Gentilcore has also explored the diffusion of this plant species within the Italian context. More recently, Lavinia Maddaluno has innovatively emphasized interest in the potato as a staple food and as an ingredient for bread-making in a framework that intertwines technical knowledge and economics.Footnote 11 Therefore, this article does not aim to rewrite or deepen the study of the diffusion of the potato in a specific European region. Instead, it uses this plant species and the nutritional importance of its tuber as a pretext to analyse the relationship between rural society and science, as well as between humans and the environment.
Section ‘In the Beginning’ analyses the first acclimatization experiments in the Po Valley and the first texts from the eighteenth and early nineteenth centuries, which discussed their results, considering the benefits for rural society while also recording the first reactions to these changes. Section ‘A Blessing and a Burden for Rural Society’ examines the continuation of these early experiments, focusing primarily on the boost given to agricultural science during the Napoleonic period, which was then carried into the Restoration era. Section ‘Interest in Congresses and Inquiries’ investigates the potato as an object of study in scientific congresses and agrarian inquiries in the mid- and late nineteenth century, particularly in relation to phytopathology and emerging ecology, always keeping in mind the relationship between political authorities, the scholarly community, and rural society.
A clarification is necessary before proceeding further. The Po Valley (Figure 1) – perhaps, even more than the Italian Peninsula itself – was a geopolitical entity that remained highly fragmented during the period in question and continued to be so until the process of national unification, which began in the second half of the nineteenth century. It was composed of many geopolitical entities, some of which depended on monarchies outside of Italy, demonstrating the strategic importance and economic appeal of this area. The eighteenth-century Po Valley reflected the high level of fragmentation typical of the early modern period, whereas the nineteenth century saw a greater degree of homogeneity, although this was not a linear process. From an agricultural standpoint, the Po Valley was, on the whole, a highly advanced region, with certain areas having been at the very forefront for centuries. In the eighteenth and nineteenth centuries, these aspects were well recognised by scholars, economists, and agriculturists alike, both foreign – such as Arthur Young and John Symonds – and Italian – among them Carlo Cattaneo.Footnote 12
Map showing the Po Valley and the places studied in this article.
Source: Our elaboration.
In the beginning
During the eighteenth century, the potato – one of the quintessential products of the Columbian ExchangeFootnote 13 – gained popularity as a food source for humans in several parts of Central and Northern Europe, though not in Italy. However, there were also Italian voices which, drawing from reports of experiences in foreign rural areas and from scientists such as the French Antoine Parmentier, praised the nutritional virtues of the tuber.Footnote 14
In Bologna, at the heart of the Po Valley, the cultivation of the potato was already documented in 1773, with the publication of a curious booklet titled succinctly yet eloquently Le patate. The author was Pietro Maria Bignami, a Bolognese entrepeneur and landowner inclined towards agronomic experimentation, whose reputation, as will be seen, extended beyond the Po Valley.Footnote 15
Bignami reported having insisted for four years with the tenant farmers of his lands for them to introduce the potato, ultimately managing to convince them despite their reluctance. He firmly believed that landowners had to be particularly persistent to overcome the rural society’s resistance to novelty. Moreover, particularly praising bread made of potato and cereals, he explained that he had it prepared by his domestic staff, ‘who enjoyed it so much that they would willingly eat it at all times’, just as it had been appreciated by anyone who had tasted it. Specifically, mixed potato and maize bread could be stored for long periods and served both rural farmers and urban workers. However, in making such a claim, Bignami betrayed a classic class-based view of food, wherein potatoes were still associated with the lower strata of the population. Nonetheless, by mixing potatoes with cereals – including rye or barley – it was possible to prepare fritters, beignets, and tagliatelle, as was already done in countries where the potato was widely consumed.Footnote 16
Another key aspect of Bignami’s discourse was the involvement of scientific institutions. An academy or a chair in agricultural science could study soil quality and teach its optimal use across different crops, not just for the introduction of the potato.Footnote 17 It should be noted that the proliferation of academies dedicated to agricultural sector improvement was a well-established phenomenon in Italy as well as throughout Europe. One of the primary objectives of these institutions was precisely to promote the acclimatization of plant species considered economically beneficial in different regions.Footnote 18
Regarding the university-level teaching of agricultural science, the situation was more complex. It is plausible that, when writing in the early 1770s, Bignami was aware of the exemplary case of the not-too-distant University of Padua, where, since the 1760s, Professor Pietro Arduino had been teaching agricultural science and overseeing a didactic-experimental garden separate from the traditional botanical garden. At the University of Bologna, on the other hand, an agriculture course was introduced around 1780, but it was only fully developed and equipped with its own didactic-experimental garden following the Napoleonic reforms in the early nineteenth century.Footnote 19 It is unsurprising that in the first edition of the catalogue of the Padua agricultural garden (1807), the potato was already present. Two varieties were also present in the first edition of the catalogue of the Bologna agricultural garden (1812).Footnote 20
Bignami’s booklet was accompanied by a text by Gaetano Lorenzo Monti, Professor of Botany at the University of Bologna and Professor of Natural History at the Institute of Sciences of the same city.Footnote 21 Monti’s signature was accompanied by that of the astronomer Giovanni Angelo Brunelli. It can be inferred that, as men of science, both had been contacted by the authority responsible for food reserves – the Assonteria d’abbondanza – to express their opinion on Bignami’s booklet. Their appendix praised Bignami’s thought and, in general, the cultivation of potatoes for food purposes, emphasizing their advantage as a food reserve and their role in integrating cereal stocks. Monti and Brunelli stressed that the success of the potato as food would be determined by the acceptance of the common people of both the countryside and the city. Only if this acceptance occurred would landowners and their tenants grasp the potential of potatoes and seriously invest in their introduction.Footnote 22
We should also consider that, when landowners undertook agronomic experiments on their estates, they were effectively foregoing a portion of their income. Most of them could certainly afford to take such a risk. However, not all approached this risk in the same way – particularly considering that, for much of the period under analysis, there was no convincing and accessible technological support, not to mention that certain solutions were costly, with long payback periods. The fact that some landowners were willing to take this risk and successfully managed to balance the experimental dimension with the demands of a profitable business is a noteworthy aspect. Among several examples from Northern Italy, we may refer to Paolo Tedeschi’s study of the Bettoni Cazzago noble family from the Brescia and Lake Garda areas in the nineteenth century, who managed their landholdings with a strong entrepreneurial spirit and an openness to innovation. Their estates produced wine, wheat, and maize, but also lemons and olive oil. This is, therefore, not an example directly related to potato cultivation, but it is indicative of the entrepreneurial spirit and the technical-scientific interest underlying several of these experiments.Footnote 23
In addition to Bologna, the Milan area was another centre in the Po Valley that promoted the acclimatization of potatoes and regarded with some apprehension the reaction of the rural population. The clergyman Carlo Amoretti was a strong supporter of the potato. He was an agriculturist and naturalist who, despite having a humanistic education, had built a solid body of technical-scientific knowledge through reading, travel, and his career as a state official and consultant. In fact, from 1780 to 1796, he served as secretary of the Patriotic Society of Milan, an economic society founded by Maria Theresa of Austria with the aim of strengthening the agricultural and manufacturing sectors of Austrian Lombardy. In 1808, under Napoleonic rule, he was appointed a member of the Mining Council of the Kingdom of Italy.Footnote 24
Amoretti took an interest in potato cultivation, acquiring information from the debates of the Patriotic Society, which included officials, landowners, naturalists, and experimenters. During the meetings, they commented on the results of experiments on potato cultivation and the processing of the tuber for food purposes, but they also discussed the existing scientific and technical literature on the subject. Given that the Patriotic Society maintained an extensive network of correspondents in rural areas, several parish priests promoted potato cultivation among rural communities north of Milan.Footnote 25
We will return to the important role of priests as promoters of agricultural innovations in rural society in the following pages. For now, we emphasize that the Patriotic Society of Milan appreciated the experiments and reflections of the aforementioned landowner Bignami from Bologna. Amoretti himself, in 1787, received from Fulgenzio Vitman, Professor of Botany at the Royal Gymnasium of Brera in Milan, Bignami’s booklet on potatoes and, following the members’ approval, informed the author of his appointment as a corresponding member.Footnote 26 In addition, among the earliest and most convinced supporters of the acclimatization of potatoes in the Po Valley was Teresa Castiglioni Ciceri (Figure 2), a noblewoman from Como, corresponding member of the Patriotic Society, and a friend of Alessandro Volta, the physicist and inventor of the battery, who had originally introduced her to this circle.Footnote 27
Portrait of Teresa Ciceri Castiglioni, painting by Giulietta Seveso Ciceri.
Source: © Musei Civici Como – Pinacoteca Civica, Como.
Castiglioni Ciceri successfully introduced potatoes in the Como area and perfected an ingenious method for obtaining textile fibres from the native lupine plant, promoting it at least among the farmers who lived and worked on her estates. The Patriotic Society analysed the reports sent on both lines of experimentation, as well as the samples submitted in both cases. Beyond the specific use of lupine for textile fibre and potatoes for food, the Patriotic Society appreciated how the increased cultivation of the former and the introduction of the latter were systematically integrated into the ecosystem and rural economy. From this perspective, Castiglioni Ciceri herself represents a case of successful synergy between the acclimatization of exotic species and the creative use of native species, albeit for different purposes. The Patriotic Society and Austrian authorities praised the experiments of the ‘Lady of Como’ (Dama Comasca) – as Castiglioni Ciceri was sometimes called – and held her up as a model for the cultivators of the region.Footnote 28
This was the solid background on which Carlo Amoretti based his positive opinion regarding the potato. As secretary of the Patriotic Society, he himself communicated to Teresa Castiglioni Ciceri the reflections and praises of the members, first regarding the experiments on the lupine stem and then on the acclimatization of the potato. In the case of the latter, he even conveyed the appreciation expressed from Vienna by Chancellor Wenzel Anton von Kaunitz-Rietberg, who, having learned from the Patriotic Society about Castiglioni Ciceri’s experiments on her estates, recommended continuing the promotion of the plant’s acclimatization and its tuber.Footnote 29 Furthermore, for the first potato acclimatization experiments organized on various lands by members and correspondents of the Patriotic Society, Ciceri Castiglioni served as a supplier of tubers.Footnote 30
To his experience as secretary of the Patriotic Society, Amoretti added, at the turn of the nineteenth century, practical experience by collaborating with a chemist from Milan on several experiments on potato-based bread-making and tuber preservation. In 1801, Amoretti’s booklet Della coltivazione delle patate e loro uso was published. In it, he provided a brief natural history of the species from its discovery by Europeans and clarified which plant he meant by the term potato, excluding other species similarly named in Italian, such as the sweet potato and the Jerusalem artichoke. Amoretti praised its advantages as a food and provided technical information on the cultivation of the plant and the use of the tuber. The text was addressed to the inhabitants of the Milan area.Footnote 31
Inevitably, Amoretti addressed the issue of pellagra, a disease that is now known to be caused by a lack of niacin. Pellagra afflicted the Po Valley until the twentieth century, especially in areas where the diet of peasants consisted almost entirely of maize, an American crop widely spread in Northern Italy during the early modern period.Footnote 32 Amoretti did not delve deeply into the aetiology of pellagra, merely mentioning the most well-known medical theories. However, in a highly pragmatic manner, he noted that where diets were more varied – with maize consumption supplemented by chestnuts, rice, and milk – the incidence of pellagra was lower. Potatoes could contribute to this dietary diversity.Footnote 33
However, Amoretti was not naive. In the booklet, he acknowledged that peasants and the less affluent citizens of the Milan area were prejudiced against potatoes both as a crop and as a food. As late as 1786, Amoretti wrote to a corresponding member residing in London – the Austrian diplomat Antonio Songa – commenting on the obstacles hindering the introduction of potatoes in the Lombard countryside, clashing ‘with common prejudice, with theoretical ignorance […], and with a sort of abhorrence that peasants feel towards this new food for them’.Footnote 34 That same year, Amoretti also wrote to Teresa Castiglioni Ciceri, lamenting Lombard farmers’ reluctance to accept potatoes on their lands, despite the Patriotic Society’s promises of prizes.Footnote 35
Nevertheless, as he expressed in his 1801 booklet, Amoretti remained convinced that one should not despair and that a negative reaction to something new was normal: it had been the same with maize bread, yet that obstacle had been overcome over the decades. It was necessary to persist in spreading potatoes, just as some landowners and parish priests were already doing, successfully convincing farmers. From an economic perspective, potatoes yielded high returns: he recalled how Giuseppe Bianchi, the parish priest of the village of Varedo, north of Milan, had harvested 3,000 libbre of potatoes from 2 pertiche of land, earning 375 lire from sales. Moreover, with proper care, Amoretti emphasized that it was even possible to achieve two harvests per year from the same plot.Footnote 36
The early studies and experiments on the spread of potatoes in the Po Valley still recorded some caution in rural society, with some landowners and parish priests aligning with the scholarly community. However, many people still displayed considerable reluctance, and according to potato advocates such as those cited, much persuasion based on evidence was still needed. A similar chiaroscuro situation was also recorded in other pioneering studies on the introduction of potatoes into the agricultural ecosystem of Northern Italy, if not strictly in the Po Valley. This was the case of Antonio Zanon, an entrepreneur and agronomist, who published his thoughts in 1767.Footnote 37 His work served as a reference point for studies in other areas of Northern Italy, despite Zanon’s primary focus being on the Udine area, in that part of the Republic of Venice not far from present-day Austria and Slovenia. This was, therefore, an ecosystem, a society, and an economy very different from those of Bologna, Milan, and Como.
A blessing and a burden for rural society
A few years later, another clergyman took an interest in the acclimatization of the potato as food. Luigi Dalla Bella was the parish priest of Arbizzano, a village near Verona. He was certainly not a scholar as well-known as Amoretti, but he, too, wished to express his opinion on the matter and make a material contribution. In 1816 – ironically, the year of Amoretti’s death – his work La coltivazione, gli usi e i vantaggi delle patate was printed. This booklet was presented as a public letter addressed to the parish priests of the area, aimed at encouraging the introduction of potatoes in the Veronese countryside.Footnote 38
The involvement of religious ministers in spreading good agricultural practices in rural areas across Europe was a trend that authorities, scholars, and the religious community itself had been insisting on for decades. The authority that priests and pastors held within rural society was seen as a means of conveying agricultural modernization. A significant example is offered by the reforms and debates concerning the training of Catholic priests across the various Italian regional states, starting with the eighteenth century. Although in different forms, seminarians were encouraged by their superiors – as well as by civil authorities and the intellectual community – to update their knowledge of the natural sciences, so that they could assist the population not only in sacramental matters but also in everyday customs and agricultural practices. Naturally, a proliferation of specialized publications emerged – booklets, catechisms, and periodicals – and efforts were made to provide religious ministers with basic training in natural and agricultural sciences.Footnote 39
In the specific case of potato cultivation and consumption, in addition to the clergymen already mentioned who took part in the experiments promoted by the Patriotic Society of Milan in the Po Valley, priests also played a crucial role in persuading local populations in Alpine valleys – where environmental and soil conditions were less favourable to a varied agriculture than those of the plains – to embrace the potato – which proved particularly well suited to that environmental context. With regard to the Apennine region, a noteworthy example is that of the Società Patria of Genoa, which in 1793 published a booklet extolling the virtues of the potato, explicitly addressed to the rural parish priests of the Republic.Footnote 40 This is one of many examples that can be found in both the Alps and the Apennines during those decades.Footnote 41
To return to the case of Luigi Dalla Bella, the urgency that prompted him to revisit the issue of potato acclimatization was the frequent hailstorms that had hit the region in recent years and the ‘peculiar delay in the succession of seasons’. It should be noted that, though in its final phase, Europe was still within the so-called Little Ice Age, which formed the backdrop to the priest’s concerns. The potato tuber, growing underground, was less vulnerable – even though not invulnerable – than cereals and legumes to hail, rain, drought, and other climatic events. The scarcity of cereals encouraged dishonest hoarding practices: although these were punished by law, potato reserves could offer the population an additional means of protection against food shortages.Footnote 42
Beyond the usual brief natural history of the potato, along with advice on cultivating the plant and preserving its tubers, Dalla Bella provided a wide variety of ways to cook them, drawing from the presumed culinary traditions of various European and American countries: boiled, roasted, in soups, battered, fried with butter, in salad with oil, onion, and thyme, or more simply pan-fried with oil or butter. They could be made into croquettes, polenta, pies, and stews, ‘depending on the mood of the cooks’. He also described various types of bread mixed with cereals, as well as coffee substitutes. He even referenced a legendary banquet hosted by the aforementioned Antoine Parmentier, a pioneer of the potato, in which all courses were based on this tuber.Footnote 43
Dalla Bella emphasized that he promoted potato cultivation to provide tenants with a staple food that was both nutritious and economical – to illustrate the scale of the difference, he noted that the same plot of land could yield either 12 quarte of wheat or 200 quarte of potatoes.Footnote 44 He had no intention of ‘teaching how to turn potatoes into exquisite dishes in the various manners of professional cooks’. Nevertheless, it is undeniable that his writing contained a hedonistic component, which was absent – at least to this extent – in the works of Bignami and Amoretti. Furthermore, Dalla Bella highlighted the potato’s potential as a remedy against scurvy and pellagra in regions where diets lacked variety. In general, he praised its dietary benefits, citing both case studies and scientific literature. He referenced the Swiss physician Hans Caspar Hirzel, who had observed that villages in the rural areas of ‘German Lorraine’ consumed large quantities of potatoes, and that their young people were beautiful, robust, and healthy.Footnote 45
The stubborn peasant, resistant to novelty, was a common topos among scholars and experimenters in the eighteenth and early nineteenth centuries, as observed in the booklets of Bignami and Amoretti, and at least hinted at in Dalla Bella’s booklet.Footnote 46 This trope was often accompanied in technical literature of the time by another recurring theme: the rural world as an idyllic and timeless dimension.Footnote 47 However, despite this oscillation between two extremes, and recognizing that even scholars and technicians harboured prejudices against rural society, the resistance of Po Valley peasants to potato cultivation remains an objective fact. Italian farmers resisted the introduction of this crop until the beginning of the nineteenth century: poorly bred or poorly selected, the first generations of potatoes produced a pulp that was often acidic and watery, and sometimes even toxic. Even its use in bread-making was not ideal and did not contribute to the popularity of the potato. Then, the situation changed. In much of north-east Italy, the famine of 1816–17 helped to convince rural society of the value of the potato.Footnote 48
Moving beyond clichés, the resistance of rural society to the acclimatization of the potato was a topic analysed in greater depth by Filippo Re, Professor of Agricultural Science at the University of Bologna from 1803 to 1814 and at the University of Modena from 1814 until his death in 1817. Re is known both for his significant epistemological contributions to agricultural science and for promoting, through the periodical Annali dell’agricoltura del Regno d’Italia, the circulation of information on both theoretical science and experimentation within the agricultural sector of the Po Valley.Footnote 49
In an 1811 issue of the Annali, Re wrote and published a letter discussing the reasons behind opposition to the introduction of potato cultivation in Northern and Central Italy. His essay was based on opinions he had gathered from landowners, farmers, peasants, and many of those who directly managed agricultural activities. The dissatisfaction he recorded stemmed primarily from the farmers’ fear that potato cultivation might reduce the portion of wheat allocated to them under the sharecropping contract. Furthermore, according to Re, in addition to the ancestral aversion to novelty, there was the fact that Italian society still did not appreciate the potato as a dish. Even farmers and peasants were reluctant to consume a food that society at large consumed only sporadically, and at best as a ‘fallback food’.Footnote 50 Thus, Re’s reflection revealed a rural society that rejected dietary hierarchies, contrary to Bignami’s 1773 booklet. From Re’s summary, it was evident that rural people refused to accept a food that even other social groups considered merely a last resort.
A farmer with whom Re had recently spoken also rejected the idea of potatoes as a substitute for wheat in years of famine. Good reserves of various cereals and legumes, as well as chestnuts for mountain people, replaced wheat better than potatoes – which were not even that tasty – that ‘you city gentlemen are too eager to recommend to us’. According to Re, a similar but milder reluctance was also demonstrated towards potatoes as livestock feed, as a wide variety of fodder was already available: Spagna grass, fenugreek, tops of various cereals, elm leaves and other trees, clover, and meadows.Footnote 51
The conversation reported by Re cannot be confirmed by another source; however, it can be considered a reasonable synthesis of at least some of the opinions gathered by the professor. It is, therefore, interesting to note how, in this case, the desire to preserve the agricultural ecosystem emerged, which in turn integrated a good reuse of human food waste that was still nutritious for livestock. In other words, acclimatization was perceived here as a threat to the established order. From this perspective, we recognize in the Po Valley a trend like what Carolyn Merchant observed in New England: the idea of the farm as an agronomic laboratory would spread in rural society well into the nineteenth century, intertwining entrepreneurial values and applied chemical progress.Footnote 52
Despite these considerations, however, Filippo Re did not oppose the spread of potatoes a priori. What he criticized were dilettante agriculturists and ‘fanatics for these tubers.’Footnote 53 However, he did not hesitate to praise studies and experiments conducted methodically and observations expressed with clarity – and we can deduce, impartiality. In this regard, Carlo Amoretti’s ‘golden book’ was worthy of praise. Furthermore, despite the negative opinion of the farmer mentioned earlier, Re argued that other experiences had shown how juicy potatoes fed to cows resulted in more milk. Moreover, potatoes could be useful as sheep fodder, an industry that was being strengthened in those very years in some areas of the Po Valley, including the Varese area.Footnote 54
In this context, Re referred to the politician and landowner Vincenzo Dandolo (Figure 3), who was experimenting with introducing Merino sheep, as well as potato cultivation in the Alpine valleys and the Po Valley, specifically in the Varese area. Dandolo – senator of the Napoleonic Kingdom of Italy and, between 1806 and 1809, administrator of Dalmatia – combined an empirical approach with considerable expertise in natural sciences, particularly chemistry, to the point that he translated in Italian (1791) Antoine-Laurent de Lavoisier’s Traité élémentaire de chimie.Footnote 55
Portrait of Vincenzo Dandolo, stipple engraving by J. D. Nargeot after Augustine Fauchery.
Source: Wellcome Collection (Public Domain).
During the 1800s and 1810s, Dandolo repeatedly published in favour of potato acclimatization for both human consumption and livestock feed. However, he also analysed its impact on the agricultural ecosystem and its actual weight on the rural economy. After articles and booklets on the subject, in 1817, he published a conclusive summary of experiments and calculations carried out in previous years (Table 1). This revealed that in his mountain experiments, the average yield was 1,172 libbre of potatoes per pertica, whereas in the plains, it was 2,400 libbre per pertica.Footnote 56
Detailed results of Vincenzo Dandolo’s experiments from 1811 to 1816Footnote 57
Source: Vincenzo Dandolo, La coltivazione dei pomi di terra considerata nei suoi rapporti colla nostra agricoltura, col ben essere delle famiglie coloniche, dei possidenti, e dello Stato (Milan, 1817), p. 148
From these data – reinforced by writings from previous years – it is possible to understand that Dandolo’s experiments initially took place primarily in mountainous areas but later achieved notable success in more lowland areas of the Varese region. He also considered the costs of cultivation and harvest, comparing the wages of workers in the mountains and the plains, which also varied according to gender. In addition, he analysed revenue, profit, and the variety of uses for tubers.
The real challenge, however, lay in convincing peasants to accept potatoes and potato-based food products. Dandolo emphasized that ‘the poorest class’ would be convinced only when widespread and well-organized potato cultivation demonstrated its benefits for the food availability of all. In this regard, he pointed out that only by maintaining constant contact with rural society – specifically mentioning peasants, artisans, and ‘rural shopkeepers’ – could one recognize that the primary fear of the people was the scarcity of bread or an increase in its price. He observed that how ‘the extreme scarcity of bread alters, so to speak, both the moral and physical physiognomy of the populace’.Footnote 58 From this reasoning, it is evident that, according to Dandolo, an abundance of potatoes would help alleviate the concerns of rural society and the lower-income population, while also convincing more people of the benefits of acclimatization.
From the documentation analysed so far, it is clear that both scholars and politicians were concerned with satisfying the populace in one way or another. The acceptance of the people – both rural and urban, actually – would ultimately determine the success or failure of the acclimatization of a species and was based primarily on how it compared to cereal resources, whether wheat, maize, or others. Part of rural society also included parish priests, landowners, and intermediary figures such as farmers and tenants, who, beyond being convinced of the potato’s value, had to promote its knowledge within the rural fabric.
Interest for the potato shown in congresses and inquiries
During the nineteenth century, the potato took root in Northern Italy. The situation varied depending on environmental and geomorphological conditions, as well as on its coexistence with other agricultural products, the local population, and other components of the ecosystem. Moreover, it was precisely in this century that natural sciences, systematically applied to enhancing the agricultural sector in the Western World, began to exert their influence.Footnote 59 The Po Valley was also affected by this phenomenon, as we have already inferred from previous examples.
One of the most urgent aspects where natural sciences were called upon to intervene in the nineteenth century was the field of phytopathology. The potato once again offers interesting examples that allow us to analyse the relationship between political authorities, the scholarly community, and rural society. Potato diseases and limiting their impact on rural society’s food supply were among the many topics addressed in the eighteenth- and early nineteenth-century texts examined so far. However, greater alarm arose even in the Po Valley when, during the 1840s, some European regions were severely affected by what we now know as potato blight, with disturbing cases reported even south of the Alpine arc. It should be noted, however, that in terms of aetiology, the debates analysed here still relied on hypotheses and were not based on a shared awareness that these diseases were caused by specific microorganisms. The hypotheses were based on common signs observed with the naked eye or under a microscope on plant samples, as well as on recording environmental conditions where plant alterations occurred. The ‘potato disease’ and blights affecting other agricultural products remained, in part, a mystery.Footnote 60
In late spring 1845, the Secretariat for the Domestic Affairs of the Savoyard State urged the Subalpine Agricultural Association (Associazione Agraria Subalpina) of Turin to analyse the disease affecting potatoes in Savoy and to find a remedy.Footnote 61 It should be considered that the Savoyard State still included the original territory of Savoy, which is now part of France. However, its capital was Turin, located at the foot of the mountains in the Po Valley, where the most important scientific and cultural institutions were based. The Association (1842–1866), for its part, was composed of politicians, landowners, and scientists who deliberated on possible strategies to strengthen the agricultural sector.Footnote 62
This case is worth considering because, although the greatest damage occurred primarily in Savoy – with estimated crop losses of two-thirds in the plains and one-quarter in the mountains, amounting to 7 million lire in damages – alarm was also raised in the Po Valley countryside. Not surprisingly, the Association of Turin conducted a systematic collection of information from various centres within the Italian part of the State. The reports were discussed among the Association’s members and compared with other cases in Europe and North America. They were also framed within the international scientific context in botany, agronomy, and chemistry, with references to the analyses conducted by Justus von Liebig and his team.Footnote 63 The potato disease cases appeared to have primarily affected the Alpine valleys and lowland areas near the mountains. It is noteworthy that the plains countryside – and, in general, areas further from Savoy – were less impacted by the disease, probably because potato cultivation was less widespread. Nevertheless, where diseased tubers had unintentionally been consumed by humans and livestock, they had caused ‘severe harm’.Footnote 64
When, in September 1846, scientists from various Italian states gathered in Genoa to discuss advancements in knowledge and technology across multiple fields, the issue of the European potato disease emerged with severity in those years. Innocenzo Ratti, a scholar of agronomy and natural sciences, presented a report on phytopathological studies conducted on potato crops in the Verbano valleys, overlooking the Po Valley, and exhibited several samples. A dedicated commission analysed and discussed Ratti’s writings and samples, comparing them with direct observations of the situation in France and microscopic studies. The goal was to determine whether these were early signs of the plant disease that had severely impacted countries like Ireland, causing great harm to the populace.Footnote 65
The appointed commission included Filippo Parlatore, Professor of Botany at the Museum of Physics and Natural History of Florence; Giuseppe Moretti, Professor of Botany and former Professor of Agricultural Science at the University of Pavia; Alphonse-Antoine-Victor-Louis, Marquis de Jessé-Charleval, engineer and landowner; and Pier Giacinto Garassini, a politician and physician with an international background. This composition thus demonstrated a strong synergy between science and landownership. Moreover, Ratti’s intervention sparked further discussions among other conference participants. For example, Giovanni Audifredi, a politician, landowner, and agrarian experimenter, provided testimony on suspect cases in the Cuneo area, to cite another example from the Po Valley. However, speakers also participated from other regions of the Italian peninsula.Footnote 66
Ratti also proposed strategies to limit crop damage, such as preventively treating healthy potato tubers either in a copper sulphate solution or in a calcium chloride solution, before burying them for germination. The commission especially approved the second proposal, as it aligned with similar experiments conducted by Dutch scientists. However, while describing the chemical treatment of potatoes, Ratti also considered its potential effects on humans. He emphasized the necessity of preventively applying chemical solutions to the tubers destined to germination and cultivation. Simply washing tubers already affected by the disease only served to limit damage and to allow the use of healthy pieces for animal feed. However, he rejected the proposal expressed some time before by Apollinaire Bouchardat, a pharmacist, physician, and soon-to-be Professor of Hygiene at the Faculty of Medicine in Paris. The latter had suggested slicing the healthy part of infected potatoes, immersing it in a hydrochloric acid solution, and still using it as food. Ratti pointed out the toxicity of such a method. Additionally, he highlighted that, in the areas he studied, the rural population had replaced rye cultivation with potatoes, and thus the disease had severe consequences on the local diet.Footnote 67
In summary, it is possible to understand that the issue was perceived as urgent and that potato cultivation had by then gained considerable importance. Moreover, although the debate on aetiology in Genoa remained open, Ratti’s experiments and observations, the discussion during the conference, and the commission’s study considered the various factors that shaped the environmental context in which suspect cases of potato disease had been reported.
Not coincidentally – as demonstrated by the maturation of biogeography, to which Alexander von Humboldt’s observations made a fundamental contribution – the nineteenth century saw a growing focus on the environmental context in which a living species was observed, considering its relationships with other specimens of the same species, as well as with other species, the geological component, and climate. This was a holistic approach, which was increasingly applied not only to wild flora but also to agricultural flora.Footnote 68 Furthermore, the link between ecology and domestic economy entered a phase of study with growing awareness, culminating at the end of the nineteenth century with the thought of Ellen Swallow Richards. Although Swallow Richards did not focus only on rural environments, the effects of disease and pollution were also studied in those contexts, as evidenced in an embryonic form by the intellectual hub of the Genoa conference in 1846.Footnote 69
However, the threat of potato disease certainly did not end in September 1846. Just a few months later, Austrian authorities in Milan were alerted to cases reported in some provinces of the Kingdom of Lombardy-Venetia, particularly in the Como area. Although potato crops in mountainous regions – where they were more widespread – were most affected, problems also arose in the plains, even though tracing the causes proved more difficult. The government gathered the opinions of the scientific community, and a dedicated commission was established at the University of Pavia to draft a comprehensive handbook, which, printed in April 1847, was intended to circulate within rural society through agronomists, physicians, parish priests, and local authorities.Footnote 70
Guidelines were provided on the selection of tubers and the area to be used for cultivation, advising against humid and clayey soils, while favouring ‘locations that were not-too low’. Once again, great attention was given to the overall context in which cultivation took place. The choice of fertilizers was also crucial, with preference for ‘calcareous substances’, ashes, coal dust, soot, residues from soap manufacturing, and ‘poultry manure mixed with well-decomposed stable manure’. Regardless of the choice, fertilizers were not to come into direct contact with the tubers. Once the seedlings sprouted, signs indicating potential problems were specified: ‘whitish spots or dirty green patches’ on leaves and stems. In such cases, to contain the spread, one had to sprinkle ash and lime around the plants and, if necessary, water with a calcium chloride solution.Footnote 71
From 1877 to 1886, after the unification of Italy into a single kingdom, the politician Stefano Jacini coordinated a parliamentary inquiry into the conditions of the agricultural sector and rural society. If we examine the Po Valley countryside, potato cultivation was undoubtedly present, but several issues remained, and its distribution was still irregular. For example, in the united countryside of Pavia and Lodi, potatoes played a minor role, whereas in nearby areas, such as the Cremona area to the east and Lomellina to the west, potato cultivation enjoyed relatively greater success.Footnote 72 In Northern Italy, the closer one got to the foothills of the Apennines and the Alps, or even ventured into the mountain valleys, the more potatoes gained importance within the agricultural ecosystem and local diet. In addition, the taste of lowland potatoes was sometimes compared to that of mountain-grown potatoes, which were considered superior.Footnote 73
Regarding phytopathology, compared to the 1840s, there was greater awareness of the causes of potato diseases, as knowledge of microorganisms – already initiated in the first half of the nineteenth century – had further advanced. For example, in the Jacini inquiry records, Senator Luigi Tanari’s report on the Emilia and Romagna countryside classified Peronospora infestans and Fusisporium solani as ‘parasitic plants’. Today, these are considered synonyms of the infamous fungus-like microorganism Phytophthora infestans (Mont.) de Bary and the fungus Fusarium solani (Mart.) Sacc.Footnote 74
Conclusion
The study of the spread of the potato in the Po Valley during the eighteenth and especially the nineteenth century has allowed for a deeper understanding of the complex dynamics between scientific innovation, agrarian economy, and rural society. The analysed cases highlight the crucial role of scholars, institutions, and intermediary figures in promoting the adoption of this crop, despite initial cultural and technical resistance. The introduction of the potato, symbolizing an innovation perceived as necessary to tackle food and social challenges, proved to be a fundamental tool for diversifying diets and improving food security, particularly for peasant communities.
Through concrete examples, the importance of relationships between scientific knowledge, agronomic experiments, and social acceptance emerged, demonstrating how these interactions influenced long-term agricultural transformations. Especially during the eighteenth century and the early nineteenth century, the efforts of experimenting landowners such as Pietro Maria Bignami, Teresa Castiglioni Ciceri, and Vincenzo Dandolo, of parish priests like Luigi Dalla Bella, and of scholars such as Carlo Amoretti and Filippo Re contributed to structuring a framework of knowledge that facilitated broader diffusion in the following decades.
Pietro Maria Bignami, for instance, worked to convince farmers of the potato’s usefulness, demonstrating through practical experiments that this crop could be successfully integrated into local agricultural systems. The production of mixed bread, based on potatoes and cereals, represented a crucial step, proving that the new crop was not merely a complement but a potential substitute in times of crisis. Carlo Amoretti, through his role in the Patriotic Society, his booklet, and his participation in acclimatization experiments, provided the agrarian community with detailed information on potato cultivation and nutritional value, helping to dispel surrounding prejudices. Luigi Dalla Bella, as a parish priest in a rural village, represented a link between academic science and practical knowledge, promoting a more systematic approach to agricultural experimentation and emphasizing the role of institutions in encouraging new crops.
The nineteenth century marked a turning point, as the potato transitioned from a marginal crop to a staple food in the diets of many rural populations in the Po Valley and its mountain valleys. However, this transition was not without obstacles. The arrival of the blight in the 1840s severely disrupted potato production across Europe, prompting naturalists and agronomists to develop new strategies to combat crop diseases. The responses to this crisis, such as those discussed at the Genoa Conference of 1846, highlighted the increasing role of applied science in managing food emergencies.
Despite the progress made, it became clear that the social acceptance of the potato was a gradual process, requiring not only technical interventions but also cultural awareness. It was necessary to overcome the initial distrust of peasants, rooted in a logic of survival, where the risk of failure with a new crop outweighed its potential benefits. This aspect reflects a broader theme: the relationship between innovation and tradition, where each change had to be negotiated within an established social and economic system.
Although this study has clarified many aspects of the introduction of the potato, some questions remain open, which could guide future research: the role of women in agrarian innovation; a comparison between the Po Valley experience and other European regions; and the environmental impact of introducing non-native crops. Thus, the history of the introduction of the potato into the Po Valley reveals far more than a simple agricultural transformation. It demonstrates the potential of science and institutions to influence agricultural practices, while also emphasizing the need to understand and respect the cultural and social dynamics of rural communities.
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