The Effect Of Crop Failure On Small Scale Village Organization

北德克萨斯大学的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种植过程，作物的水分来自降水和储存的土壤水分。今天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，从而应对作物产量随时间的波动。在丰水年和丰产年，环境承载能力可以大大增加，导致丰产年和人口增长加快。但干旱年份会导致严重的作物歉收和饥荒。目前关于当代旱地农业的许多研究侧重于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的“实验”来研究。一些社会发展出了能够带来长期成功的管理实践，而另一些社会则采用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，可以让我们深入了解哪些变量对长期可持续旱地农业最重要。Nagaoka和Kohler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。先前关于这一主题的考古研究主要集中在区域尺度上的作物产量建模，这需要对土壤质量等变量进行大量假设，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萎蔫点（一个已知的土壤湿度水平，在这个水平上植物不能吸收水分），专注于土壤湿度对大型普韦布洛村庄周围当地农田作物歉收的潜在影响。这项研究将在科罗拉多州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作社会崩溃的警示故事。众多的大型多层普韦布洛人与曾经居住在该地区的大量人口交谈。然而，到了公元1200年代晚期，这些社区都被遗弃了。长期和严重的干旱通常被认为是导致崩溃的原因。然而，在过去的一千年里，有几个干旱时期并没有导致崩溃，这表明有更多的因素导致旱地农业的长期失败或可持续性。这组研究人员拥有考古学、环境科学、水文学、遥感和地理信息系统的背景，他们将利用这些知识来了解在大的普韦布洛村庄，作物歉收的可能性是如何根据土壤类型、地形特征和植被而变化的，以及这些因素在高降水和干旱期间是如何随时间变化的。该小组将提出研究农业生产力的新方法，这些方法可应用于世界上其他旱地农业重要地区，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.