The Atacama Desert is among the driest places on Earth, yet ancient agricultural systems are present in the region. Here, we present a study of terraced agricultural soils in the high-altitude eastern margin of the Atacama Desert in northern Chile, mainly dating to the Late Intermediate Period (ca. 950–1400 AD) and Inka period (ca. 1400–1536 AD). Terraced fields were compartmentalized to distribute limited irrigation water originating mainly from springs. Natural soils used for agriculture are mostly Aridisols developed on Pleistocene alluvial fan terraces and hillslopes underlain by volcanic bedrock. One research objective is to evaluate long-term soil change from agriculture. In this hyperarid climate, agriculture is only possible with irrigation, so natural soils on the same geomorphic surface adjacent to irrigated soils provide baseline data for assessing anthropogenic soil change. Data from soil profiles and surface transects indicate intentional soil change through terracing, removal of soil rock fragments, and probable fertilization. Agricultural soils have anthropogenic horizons ranging from 16 to 54 cm thick. Most agricultural soils have higher phosphorus levels, suggesting enrichment from fertilization. Changes in soil organic carbon and nitrogen are also evident. Unintentional anthropogenic soil change resulted from CaCO₃ input through irrigation with calcareous spring water. Initial studies suggest that agriculture here was sustainable in the sense of conserving soils, and maintaining and possibly improving soil productivity over centuries.

中文翻译：

---

智利阿塔卡马沙漠古代灌溉农业梯田的土壤

阿塔卡马沙漠是地球上最干旱的地方之一，但该地区存在古老的农业系统。在这里，我们对智利北部阿塔卡马沙漠高海拔东部边缘的梯田农业土壤进行了研究，主要可追溯到中后期（约公元 950-1400 年）和印加时期（约公元 1400-1536 年） ）。梯田被划分为主要来自泉水的有限灌溉水。用于农业的天然土壤主要是在更新世冲积扇阶地和火山基岩下的山坡上发育的旱地土。一项研究目标是评估农业造成的长期土壤变化。在这种极度干旱的气候下，农业只有通过灌溉才能实现，因此，与灌溉土壤相邻的同一地貌表面上的天然土壤为评估人为土壤变化提供了基线数据。来自土壤剖面和地表横断面的数据表明，通过梯田、去除土壤岩石碎片和可能的施肥来有意改变土壤。农业土壤具有 16 至 54 厘米厚的人为层。大多数农业土壤的磷含量较高，表明施肥使土壤富集。土壤有机碳和氮的变化也很明显。CaCO 引起的无意的人为土壤变化 农业土壤具有 16 至 54 厘米厚的人为层。大多数农业土壤的磷含量较高，表明施肥使土壤富集。土壤有机碳和氮的变化也很明显。CaCO 引起的无意的人为土壤变化 农业土壤具有 16 至 54 厘米厚的人为层。大多数农业土壤的磷含量较高，表明施肥使土壤富集。土壤有机碳和氮的变化也很明显。CaCO 引起的无意的人为土壤变化₃通过石灰质泉水灌溉输入。初步研究表明，这里的农业在保护土壤的意义上是可持续的，几个世纪以来保持并可能提高土壤生产力。