In the intricate tapestry of ancient Chinese agricultural wisdom, the concept of San Cai—the harmonious triad of heaven, earth, and humanity—stands as a cornerstone of sustainable farming philosophy. Historically, this framework placed humanity not only as a beneficiary of natural forces but as a deliberate and proactive agent capable of shaping the environment to enhance productivity. Contrary to simplistic views that ancient farming was merely submissive to seasonal cycles or natural conditions, emerging research highlights a nuanced understanding of human agency, especially in soil fertilization practices spanning millennia.
Tracing back to pre-Qin China, documented in authoritative historical texts such as Zhou Li (周礼), agricultural officials assumed specialized roles in interpreting land characteristics and applying suitable fertilization methods. These early records underscore a vital understanding: the land’s fertility was not static but could be enhanced through informed human intervention. Fertilization was not a passive consequence of seasonal rhythms but an active manipulation by skilled laborers who melded empirical knowledge with natural cycles, a testament that human work was central to agrarian success.
The philosophical underpinnings can be seen vividly in the classical text Lü Shi Chun Qiu (吕氏春秋), which encapsulates farming as a dynamic interplay “carried out by humans, nourished by the land, and sustained by the heavens.” This triadic acknowledgment elevates humanity from a mere laboring class to the pivotal fulcrum in agricultural productivity. However, early practice tended to revere the timing and natural conditions more than human intervention, reflecting a worldview where adherence to nature’s established order was paramount.
Up until the Song Dynasty (960–1279 AD), human labor in fertilization was often regarded as complementary to the rhythms dictated by nature, rather than as a primary driver of fertility management. Yet, demographic pressures and intensifying cultivation techniques precipitated a paradigm shift. The explosion in population, exceeding 100 million by the early 12th century, exerted tremendous strain on arable land resources, necessitating innovations in soil management to sustain growing food demands.
It was within this context that Chen Fu (陈旉), a prominent agricultural thinker, synthesized centuries of traditional knowledge with practical farming insights to propose the “Theory of Perpetual Soil Fertility” (地力常新壮). His revolutionary idea postulated that soil fertility need not inexorably decline under continuous cultivation; rather, human fertilization efforts could maintain or even rejuvenate soil vitality indefinitely. This directly challenged entrenched notions of the time that saw soil depletion as an unavoidable fate.
Chen Fu’s theory connected the dots between diligent application of organic matter and sustained crop productivity, effectively positioning proactive human intervention as an equal partner to natural forces within the San Cai framework. Fertilization evolved from a reactive measure to a strategic, systematic practice aimed at preserving a perpetual agricultural equilibrium. This conceptual breakthrough not only advanced agronomic science but also stimulated renewed agricultural philosophies emphasizing soil stewardship.
The momentum generated by Chen Fu’s insights found concrete expression in Wang Zhen’s Nong Shu (王祯农书), a comprehensive farming manual from the Yuan Dynasty. Wang articulated the practical consequences of neglecting soil health, stating clearly the risks of soil exhaustion, declining crop vitality, and diminished yields when fertilization was ignored. By advocating for the storage and decomposition of manure to sustain soil fertility, Wang’s manual codified the critical role of manure recycling as a cornerstone of ancient Chinese fertilization methodology.
Beyond the procedural and technical dimensions, the anthropological fabric of fertilization practices reveals a deeply social and cultural narrative. The act of fertilization was never detached from the societal milieu; instead, it was enmeshed within a web of economic policies, land tenure systems, and social hierarchies. The transition from feudal landholding to more monetized, lease-based systems during the Ming and Qing Dynasties heightened farmers’ incentives to invest in fertilization due to shifting property relations.
Population surges in the Ming and Qing eras—surpassing 200 million and later 400 million—intensified the man-land contradiction, particularly in southern China. Diminishing per capita arable land compelled farmers and landowners alike to adopt more proactive measures to sustain yields despite shrinking landholdings. Monetary rent systems and perpetual leases paradoxically stimulated investment in soil fertility, as tenants aimed to secure their livelihoods and landlords sought to preserve the value of their holdings.
This socioeconomic context underscores a fundamental evolution in the San Cai principle: humanity’s role now extended beyond physical labor to encompass adaptive strategies in negotiating social, economic, and political landscapes. The Chinese concept of 人和 —human harmony—embodied this higher form of fertilization, blending ecological knowledge with social cooperation and conflict resolution to maintain agricultural productivity sustainably.
Visual representations from the period, such as detailed illustrations of farmers actively carrying manure water and applying it with specialized tools (as depicted in Figure 2), provide vivid evidence of this labor-intensive, knowledge-driven activity. The use of manure scoops and careful distribution techniques denote a refined expertise honed over centuries, emphasizing the human capacity for innovation within environmental constraints.
Ancient Chinese fertilization practices thus represent one of the earliest examples of integrated agroecological management, where empirical observation, labor, and societal organization coalesced into a resilient system. The San Cai framework’s emphasis on the triadic unity of heaven, earth, and humanity elevated fertilization from a mere agricultural chore to a philosophical reflection on mankind’s stewardship over nature.
The lasting influence of these principles continues to resonate, particularly as modern agriculture grapples with sustainability and soil degradation. The traditional Chinese understanding that human labor can actively regenerate soil fertility challenges contemporary assumptions of inevitable land exhaustion and introduces valuable perspectives on regenerative agricultural practices.
Moreover, examining fertilization through the dual lenses of labor and social dynamics offers an enriched viewpoint on rural economies of the past. It highlights how environmental practices were inseparable from the fabric of human relations, economic incentives, and governance structures. Fertilization acted as a nexus where natural science met human agency and societal organization.
The historical trajectory from nature-centered, passive agricultural practices to a more human-dominated, proactive soil management highlights the adaptability embedded within ancient agricultural systems. This evolution reflects the innate human ability to recognize constraints and innovate, ensuring the continuity of food production across fluctuating environmental and social challenges.
In summary, the ancient manuring principles derived from the San Cai theory provide profound insights into how humans have historically balanced the forces of nature with conscious intervention. The fusion of philosophy, practical agronomy, and social adaptation yielded a fertilization system capable of sustaining some of history’s most remarkable agricultural civilizations—a testament not only to human labor but to the wisdom of viewing humanity as an active, harmonious agent within the natural world.
Subject of Research: Manuring principles and agricultural fertilization practices in ancient China within the framework of the San Cai theory.
Article Title: The manuring principles in ancient China from the perspective of the San Cai theory.
Article References:
Ouyang, H., Shang, X. The manuring principles in ancient China from the perspective of the San Cai theory.
Humanit Soc Sci Commun 12, 1457 (2025). https://doi.org/10.1057/s41599-025-05815-7
Image Credits: AI Generated
