|Agricultural strategies during the development of complex societies on the Loess Plateau and Tibetan Plateau
|Place of Conferral
|社会复杂化 Social complexity 农业策略 Agricultural strategy 黄土高原 Loess Plateau 青藏高原 Tibetan Plateau 集约化农业 Intensive agriculture 农牧共生系统 Symbiotic system of farming and herding 施肥实验 Manuring experiment 稳定同位素分析 Stable isotope analysis
复杂社会的出现是史前人类社会发展的里程碑式变革，农业革新创造的粮食盈余支撑了社会的复杂化发展。已有研究表明，世界各地社会复杂化进程中的农业策略存在明显的区域差异。黄土高原地区是中华文明的起源地之一，新石器时代根植于黄土高原的粟作农业面临粟（Setaria italica）、黍（Panicum miliaceum）产量低和黄土区肥力有限的瓶颈，然而，目前对粟作农业如何突破粮食生产的瓶颈从而支撑新石器时代中国北方的社会复杂化进程知之甚少。青藏高原处于华夏文明的边缘地带，极端严酷的自然条件和相对匮乏的自然资源对人类生理和生计构成了双重挑战，人类从登上高原到定居高原再到建立以吐蕃帝国为代表的高寒文明，彰显着人类的进取心和对严酷环境的适应能力，但是，目前对支撑青藏高原文明形成的农牧经济的发生与发展过程的了解仍然不清晰。
（1）施粪肥会显著提升粟、黍的δ15N值，而且粟、黍的δ15N值会随着施肥量的增加而升高；长期、大量粪肥投入对粟、黍15N值的提升幅度约为6‰。粟叶片的δ15N值比籽粒系统性的高出+1.6 ± 0.1‰，同位素重建食谱时需要考虑植物不同部位δ15N值的差异。考古遗址出土的粟、黍炭化种子δ15N值小于+1‰很可能代表不受粪肥影响或受到轻度施加粪肥的影响，介于+1‰ ~ +4‰之间很可能代表受到中度施加粪肥的影响，高于+4‰很可能代表受到重度施加粪肥的影响。
（2）至晚在距今5500年前，以大地湾遗址为代表的中国北方粟作农业社会已经出现了正反馈循环的农业模式：人吃粟米，猪吃稃壳；圈养家猪，收集粪便；猪粪肥田，提高产量。这种农业模式通过粟、黍种植与家猪（Sus scrofa domesticus）饲养的紧密结合形成了可持续的集约化粟作农业系统，可以在不扩大种植面积、减少农业对环境影响的条件下提高农业产量，从而克服粟、黍产量低和黄土肥力有限的瓶颈，实现可持续的农业生产，为中国北方的社会复杂化进程提供了经济基础。
（3）距今7000-3600年，粟作农业在黄土高原地区的史前生业经济中一直占据主导地位。粟、黍和家猪紧密结合形成的粟作农业系统支撑了以大地湾、圪垯川、下河、西坡、双槐树等遗址为代表的早期复杂社会发展；距今4000年左右，黄牛（Bos taurus）、绵羊（Ovis aries）和山羊（Capra hircus）等新的生产要素传入北方后嵌入了原有的粟作农业系统，形成了粟、黍与猪、牛、羊组成的综合农业系统，牛、羊可以将黄土高原地区不宜耕种的山地和深沟中不能被人直接利用的草地资源转换为人类可食用的肉类和奶制品，并且为人类提供皮毛、畜力以及更多的粪肥，大幅度地提升粟作农业生产力，从而支撑以石峁、陶寺和二里头遗址为代表的城市和国家的崛起。
（4）青藏高原的农业策略演变和社会复杂化进程主要经历了三个阶段。第一阶段（距今5200-4000年）：从黄土高原传播而来集约化粟作农业系统帮助史前人类定居于青藏高原东北部、东部和南部地区海拔介于2500-3300 m的河谷地区，高原最早的农业定居聚落开始出现，开启了青藏高原的社会复杂化进程；第二阶段（距今4000-3500年）：跨大陆传播而来的大麦（Hordeum vulgare）、小麦（Triticum aestivum）和绵羊、山羊、黄牛进入高原，这些新的生产要素被纳入了青藏高原原有的粟作农业系统，在河谷区形成了麦、粟混合种植和猪、牛、羊畜牧结合的多样化农业生产体系，支撑青藏高原河谷地区的农业聚落出现了一些明显的社会复杂化信号，但社会复杂化程度依然停留在较低水平；第三阶段（距今3500年以来）：麦作农业快速发展并逐渐取代了粟作农业，麦类作物的耐寒属性使得青藏高原的农业聚落快速扩展到了海拔3000-4000 m的高海拔河谷地区。青藏高原本土的关键家畜——牦牛（Bos grunniens），在这一时期被成功驯化。河谷区形成了麦类作物种植与牛、羊畜牧并重的集约化麦作农业，高海拔草地形成了放牧牦牛、绵羊和山羊并利用其奶制品的游牧业，高海拔草地的游牧业与低海拔河谷的集约化麦作农业构成的二元经济格局最终发展为了高度适应青藏高原环境的农牧共生系统，奠定了青藏高原持续至今的食物生产格局，帮助史前人类大规模开发了高原的生存资源，最终支撑了青藏高原以象雄文明和吐蕃帝国为代表的复杂社会兴起。
The emergence of complex societies represents one of the major developments of human prehistory. It has been shown that diverse agricultural strategies were implemented to produce the increased grain surplus necessary to allow the development of complex societies across the world. The Loess Plateau is one of the cradles of Chinese civilization, and the millet-pig-based agriculture in this region faced the bottleneck of low millet yields and limited fertility in the loess soil. Little is known, however, about the millet-pig system that developed in Neolithic North China and ultimately underpinned the more complex societies, such as cities and states, in this region. The Tibetan Plateau is the marginal region of Chinese civilization. The extreme environments of the Tibetan Plateau offer considerable challenges to human physiology and livelihood. The process from the seasonal exploration to the sustained settlement and even to the establishment of the alpine civilizations represented by the Tubo Empire on the Tibetan Plateau demonstrates the human enterprise and adaptability to the harsh environment. However, our understanding of the processes of occurrence and development of the agropastoral economy that underpinned the alpine civilizations on the Tibetan Plateau remains unclear.
Therefore, this study mainly employs stable isotope analysis to study the economic base of complex societies. Firstly, modern manuring experiments on foxtail millet (Setaria italica) and common millet (Panicum miliaceum) were conducted, confirming that δ15N values of millets are reliable indicators of manuring practices and establishing a framework for interpreting the δ15N values of archaeological millet remains. Subsequently, the typical millet-pig-based agricultural site (Dadiwan in Qin'an County, Gansu) on the Loess Plateau and newly discovered, investigated, and excavated archaeological materials from the Yarlung Zangbo River Basin in the southern Tibetan Plateau were selected to compare agricultural strategies during the development of complex societies between the culturally central and marginal regions in East Asia.
Key findings of this research include:
(1) Manuring could significantly elevate the δ15N values of foxtail and common millets, and these values increase with the amount of manure applied. The long-term and large-scale application of manure increases the δ15N values of millets by about 6‰. The δ15N values of millet leaves are on average +1.6 ± 0.1‰ higher than those of seeds, and this difference must be considered when reconstructing the diet using stable isotopes. Archaeological charred millet grains with δ15N values below +1‰ likely represent no/low manure input, those between +1‰ and +4‰ probably indicate medium manure application, and those above +4‰ probably indicate high manure application.
(2) Our data from studies of phytoliths and starches from pig (Sus scrofa domesticus) dental residues and stable isotopes of millet grains excavated from the Dadiwan site demonstrate that an intensive crop-livestock system was in practice by at least 5500 years ago. This novel system, characterized by the feeding of millet crop residues to pigs and the fertilization of millet fields with pig and/or human dung, enabled sustainable intensification in agriculture and fed the early complex societies in North China.
(3) From around 7000 to 3600 years ago, millet agriculture remained dominant in the subsistence economy of the Loess Plateau. The integrated millet and pig system supported the development of early complex societies represented by sites such as Dadiwan, Gedachuan, Xiahe, Xipo, and Shuanghuaishu. Around 4000 years ago, new elements of production, such as cattle, sheep and goat were integrated into the existing millet agricultural system. This led to the formation of a comprehensive agricultural system combining millet, pig, cattle, sheep, and goat. These domesticated herbivores were able to convert unfarmable mountainous and deeply gullied grassland resources on the Loess Plateau into meat and dairy, providing humans with fur, draft power, and additional manure. This significantly enhanced millet agricultural productivity, thus supporting the rise of cities and states represented by Shimao, Taosi, and Erlitou.
(4) The agricultural strategies and the process of social complexity on the Tibetan Plateau can be broadly divided into three periods. Period 1 (approximately 5200-4000 years ago): The intensive millet agriculture, spread from the Loess Plateau, enabled prehistoric humans to occupy the river valley areas at elevations between 2500 to 3300 m of the plateau. This led to the emergence of the earliest agricultural settlements in the plateau, marking the beginning of the s process of social complexity on the Tibetan Plateau. Period 2 (approximately 4000-3500 years ago): Cereal crops such as barley and wheat, and domesticated herbivores such as sheep, goats, and cattle, were introduced to the plateau through trans-Eurasian exchange. These new elements were integrated into the existing millet agricultural system, resulting in diverse agriculture combining barley, millet, pig, cattle, and sheep in the river valley regions. This led to some signals of social complexity in the agricultural settlements of the Tibetan Plateau, although the level of social complexity remained relatively low. Period 3 (approximately 3500 years ago to the present): barley-wheat farming rapidly developed and gradually replaced millet farming. The cold-tolerant properties of barley and wheat allowed agricultural settlements to expand rapidly to high-altitude river valley regions at elevations between 3000 to 4000 m. During this period, the key native animal of the plateau, the yak, was successfully domesticated. An intensive barley-wheat agriculture that attaches equal importance to crop cultivation and cattle, sheep and goat husbandry formed in river valleys. A nomadic herding of yak, sheep and goat and the use of dairying emerged in grassland. the nomadic pastoralism of high-altitude grassland and the intensive barley-wheat agriculture of low-altitude river valleys have finally developed a symbiotic system of farming and herding that is highly adapted to the environment of the Tibetan Plateau. It laid the foundation for the food production pattern of the Tibetan Plateau that continues to this day, helped prehistoric people to exploit the survival resources of the plateau on a large scale, and ultimately supported the rise of complex societies represented by the Zhang Zhung civilization and Tubo Empire on the Tibetan Plateau.
(5) The natural resource endowments of the Loess Plateau and the Tibetan Plateau have significantly influenced their decision of agricultural strategies and processes of social complexity. The Loess Plateau is characterized by loose, abundant and easily cultivable soil. The rainfall and accumulated temperature are especially suitable for the development of millet agriculture. Therefore, the intensive millet-pig agriculture has been provided sufficient food surplus to support the emergence of highly complex societies in this region. On the other hand, the most prominent characteristic of the Tibetan Plateau is the scarcity of arable land, while grasslands and water resources are abundant. The cold-tolerance property of barley and wheat allows them to adapt to the high-altitude and low-temperature environment of the plateau. Additionally, the abundant glacial meltwater in the plateau's river valleys can provide convenient irrigation conditions for barley and wheat during the dry seasons. Thus, the Tibetan Plateau rapidly and fully embraced the barley and wheat introduced from transcontinental transmission. However, the extremely limited arable land on the Tibetan Plateau restricts the crop and livestock husbandry in the river valley regions from producing sufficient food surplus to support complex societies. Consequently, the pastoral economy that utilizes high-altitude grassland resources played a crucial role in the development of complex societies on the Tibetan Plateau.
|MOST Discipline Catalogue
|理学 - 地理学 - 自然地理学
|杨继帅. 黄土高原和青藏高原社会复杂化进程中的农业策略[D]. 兰州. 兰州大学,2023.
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