The Effect Of Crop Failure On Small Scale Village Organization

北德克萨斯大学的丽莎长冈博士及其同事和华盛顿州立大学的蒂莫西科勒博士将进行研究，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耕作方法，作物的水来自降水和储存的土壤水分。当今许多社会依赖旱地农业;长期成功的关键是应对水资源供应的波动，从而应对作物产量的波动。在多雨和多产的年份，环境承载能力可以大大增加，从而导致丰收年和人口增长加快。但干旱年份可能导致严重的作物歉收和饥荒。目前对当代旱地农业的大部分研究都集中在通过转基因作物品种以及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可用性波动的社会影响，因为它提供了许多过去的“实验”，使用各种管理技术进行研究。一些社会制定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方法。了解一些依赖旱地农业的社会成功而另一些社会失败的条件可以深入了解哪些变量对长期可持续旱地农业最重要。长冈博士和科勒博士及其研究小组将研究气候变化、水资源供应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主要集中在区域范围内的作物产量建模，这需要对土壤质量等变量进行大量假设，这些变量在史前环境中难以测量。在这项研究中，研究小组将通过记录旱地土壤的萎蔫点（一种已知的土壤湿度水平，在这种水平下，植物无法提取水分），重点研究土壤湿度对大型普韦布洛村庄周围当地农田作物歉收可能性的影响。这项研究将在科罗拉多西南部的梅萨维德地区进行，在那里，史前文化的变化经常被用来作为社会崩溃的警示故事。众多的大型多层普韦布洛说话，曾经生活在该地区的大量人口。然而，到了公元1200年代后期，这些社区都被遗弃了。长期的严重干旱经常被认为是崩溃的原因。然而，在过去的一千年里，有几次干旱并没有导致崩溃，这表明，对于哪些因素导致旱地耕作的失败或长期可持续性，还有更多的东西需要了解。研究人员团队拥有考古学，环境科学，水文学，遥感和地理信息系统的背景，他们将利用这些背景来了解大型普韦布洛村庄作物歉收的可能性如何根据土壤类型，地形特征和植被而变化，以及这些在降水量较高的时期和干旱期间如何随时间变化。该小组将提出研究农业生产力的新方法，可应用于世界上旱地耕作重要的其他地区，该项目的跨学科重点也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.