Eolian Deposition and Soil Fertility in a Prehistoric Agricultural Complex in Central Arizona, USA

Abstract

Prehistoric farmers in arid and semiarid ecosystems commonly used rock alignments to concentrate water and sediments on their fields. Previous research has emphasized the importance of runoff from organic matter‐rich uplands as a mechanism for soil nutrient replenishment. However, eolian inputs to these dryland ecosystems might also contribute substantially to mineral‐derived nutrient pools. We explored the relative importance of eolian deposition, prehistoric agriculture, and the presence of rock alignments on soil properties in a semiarid grassland in Arizona. Subsurface soils behind natural rock alignments are finer in texture than soils unbound by rock alignments, while subsurface soils behind agricultural rock alignments coarsen relative to unbound soils. Neither rock alignments nor estimated crop yields had detectable effects on mineral‐derived nutrient pools. In contrast, eolian deposition is an important source of soil mass and nutrients to modern soils. While dust deposition likely reduced soil heterogeneity across this landscape, it could have also contributed to the sustainability of prehistoric agriculture.

An oasis soil reference collection for the identification and study of ancient cultivated soils in arid environments (Oasis of Masafi, United Arab Emirates)

“…The enrichment in P can be attributed to the presence of apatite, a mineral present in igneous and metamorphic rocks as well as in the dunes located west of Masafi as a part of the Rub al‐Khali desert (El‐Sayed, 1999). This is similar to other studies in arid agrosystems (Nakase et al, 2014; Reynolds et al, 2001; Swap et al, 1992) where apatite contributes to mineral‐derived nutrient pools, supplying soils mainly with P and Zn. P is one of the most immobile elements in soils, whereas Ca, Sr, Mg, and Na are among the most soluble ones.…”

“…By combining several disciplines such as geomorphology, sedimentology, pedology, geochemistry or paleo‐ecological analyses, the main working hypothesis is that land management creates characteristic soil facies that can be recognised within buried soils. In this way, a large diversity of contexts has already been explored in several arid regions worldwide, which have improved our knowledge about past farming (Bruins, 2007; Contreras et al, 2014; Hesse & Baade, 2009; Lisitsina, 1976; Meister et al, 2017; Miles et al, 2010; Nakase et al, 2014; Nordt et al, 2004; Pietsch & Kühn, 2017; Sandor & Homburg, 2017; Sullivan, 2000; Woodson et al, 2015).…”

Farming the Great Sage Plain: Experimental Agroarchaeology and the Basketmaker III Soil Record

“…Combining the various lines of evidence (soil, modern and historical agri/cultural, archaeological) available to us and investigating desert farming at the scale of environmental diversity reveals patterns in long-term regional human-landscape interaction. This study joins many others in elucidating soil behavior as influenced by US Southwest farming cultures (Bellorado 2009(Bellorado , 2007Dominguez and Kolm 2005;Homburg and Sandor 2011;Homburg, Sandor, and Norton 2005;Nakase et al 2014;Norton, Sandor, and White 1998;Sandor and Eash 1991;Sandor and Homburg 2011;Sullivan 2000) and, in particular, the importance of indigenous and local farming knowledge in managing these soils (Critchley, Reij, and Willcocks 1994;Norton, Pawluk, and Sandor 2003;Pawluk, Sandor, and Tabor 1992;Wall and Masayesva 2004).…”

Hohokam Canal Irrigation and the Formation of Irragric Anthrosols in the Middle Gila River Valley, Arizona, USA

“…This is largely a result of the difficulty in identifying such soils: for the most part they are no longer visible on the surface and have been obscured or destroyed by historic and modern disturbances. This stands in contrast to the series of archaeological soil studies that have been undertaken in dryland agricultural fields (e.g., rock alignment terraced fields, rock pile systems) in parts of Arizona such as the Northern Tucson Basin (Fish, Fish, & Madsen, ), Lower Verde Valley (Homburg & Sandor, ), Tonto Basin (Homburg, ), Safford Basin (Homburg, Sandor, & Lightfoot, ), and elsewhere (e.g., Nakase et al., ). Means (), during the earliest soil survey of the Salt River Valley, was the first to note the correlation of “heavy” clay‐enriched soils (termed “Salt River adobe”) with ancient canals and hypothesized they might be prehistoric irrigation‐affected soils.…”