The Effect Of Crop Failure On Small Scale Village Organization

北得克萨斯大学的Lisa Nagaoka博士及其同事和华盛顿州立大学的Timothy Kohler博士将开展研究，研究气候变化，特别是干旱对依赖旱地农业的社会的影响。非灌溉或旱地农业是干旱地区的一种种植过程，那里农作物的水来自降水和储存的土壤水分。今天的许多社会依赖旱地农业；长期成功的关键是处理可用水的波动，从而解决作物产量随时间的波动。在多雨和多产的年份，环境承载能力可以大大增加，从而导致作物丰收年和人口增长增加。但干旱年份可能导致严重的作物歉收和饥荒。目前对现代旱地农业的大部分研究都集中在通过转基因作物品种和更好的土壤和水管理来提高作物产量。考古学很好地理解了未能处理水资源供应波动的社会影响，因为它提供了许多过去使用各种管理技术进行研究的“实验”。一些社会发展了导致长期成功的管理做法，而另一些社会则采取了导致社会崩溃的做法。了解一些依赖旱地农业的社会成功而另一些社会失败的情况，可以洞察哪些变量对长期可持续的旱地农业最重要。Nagaoka和Kohler以及他们的研究团队将研究气候变化、可用水和旱地农业生产力之间的关系。以前关于这一主题的考古研究侧重于在区域尺度上对作物产量进行建模，这需要对土壤质量等变量做出许多假设，而这些变量在史前背景下很难测量。在这项研究中，研究小组将通过记录旱地土壤的枯萎点，重点研究土壤水分对大型村落周围农田局部范围内作物歉收可能性的影响。旱地土壤的枯萎点是已知的土壤水分水平，在该水平上，植物无法提取水分。这项研究将在科罗拉多州西南部的梅萨维德地区进行，那里的史前文化变迁经常被用作社会崩溃的警示故事。无数的大型多层村落向曾经生活在该地区的大量人口说话。然而，到了公元12世纪末，这些社区都被遗弃了。长期而严重的干旱经常被认为是坍塌的原因。然而，在过去的数千年中，有几次干旱没有导致崩溃，这表明需要更多地了解导致旱地耕作失败或长期可持续性的因素。研究小组拥有考古学、环境科学、水文学、遥感和地理信息系统方面的背景，他们将利用这些背景了解普韦布洛大村庄作物歉收的可能性如何根据土壤类型、地形特征和植被的不同而变化，以及在降雨量较大和干旱期间这些因素如何随时间变化。该团队将产生研究农业生产力的新方法，这些方法可以应用于世界上其他旱地农业重要的地区，该项目的跨学科重点还将为学生提供独特的教育和培训机会。

Dr. Lisa Nagaoka and colleagues, of the University of North Texas, and Dr. Timothy Kohler, of Washington State University, will undertake research to study the impact of climate change, particularly drought, on societies reliant on dryland agriculture. Non-irrigated or dryland agriculture is a cultivation process in arid areas where water for crops comes from precipitation and from stored soil moisture. Many societies today rely on dryland agriculture; the key to long-term success is dealing with fluctuations in the availability of water, and thus crop yield, across time. During wet and productive years, environmental carrying capacity can greatly increase, resulting in good crop years and increased human population growth. But dry years can lead to significant crop failure and famine. Much of the current research on contemporary dryland agriculture focuses on increasing crop yield through genetically modified crop varieties and better soil and water management. Archaeology is well placed to understand the societal impacts of a failure to deal with fluctuations in water availability because it provides numerous past "experiments" using a variety of management techniques to study. Some societies developed management practices that led to long-term success, while others adopted approaches that resulted in societal collapse. Understanding the conditions under which some societies reliant on dryland agriculture succeed while others fail can provide insight into which variables matter most in terms of sustainable dryland farming over long periods of time.Drs. Nagaoka and Kohler and their research team will study the relationship between climate change, water availability, and dryland agricultural productivity. Previous archaeological research on this topic has focused on modeling crop yield at the regional scale, which requires numerous assumptions about variables such as soil quality that are difficult to measure in a prehistoric context. In this study, the research team will focus on the effects of soil moisture on the potential for crop failure at the local scale of farmland around large pueblo villages by documenting the wilting point of dryland soils, a known level of soil moisture at which no water can be extracted by plants. The research will be conducted in the Mesa Verde region of southwestern Colorado, where prehistoric culture change is often used as a cautionary tale of societal collapse. The numerous large multi-storied pueblos speak to the large population that once lived in the region. Yet, by the late AD 1200s, these communities were all abandoned. A prolonged and severe drought is often cited as a cause for the collapse. However, there were several periods of drought during the previous thousand years that did not lead to collapse indicating that there is more to learn about what factors lead to failure or sustainability of dryland farming over the long term. The team of researchers has backgrounds in archaeology, environmental science, hydrology, remote sensing, and geographic information systems, which they will use to understand how the likelihood of crop failure varied at large pueblo villages depending on soil type, topographic features, and vegetation, and how these varied across time during periods of higher precipitation and during drought. The team will generate new methods for studying agricultural productivity that can be applied in other areas of the world where dryland farming is important, and the interdisciplinary emphasis of the project will also provide unique educational and training opportunities for students.