Using Maize δ15N values to assess soil fertility in fifteenth- and sixteenth-century ad Iroquoian agricultural fields

Abstract

Native Americans developed agronomic practices throughout the Western Hemisphere adapted to regional climate, edaphic conditions, and the extent of dependence on agriculture for subsistence. These included the mounding or "corn hill" system in northeastern North America. Iroquoian language speakers of present-day New York, USA, and Ontario and Qué bec, Canada were among those who used this system. While well-known, there has been little archaeological documentation of the system. As a result, there is scant archaeological evidence on how Iroquoian farmers maintained soil fertility in their oftenextensive agricultural fields. Using δ 15 N values obtained on fifteenth-and sixteenth-century AD maize kernels from archaeological sites in New York and Ontario, adjusted to take into account changes that result from charring as determined through experiments, we demonstrate that Iroquoian farmers were successful at maintaining nitrogen in their agricultural fields. These results add to our archaeological knowledge of Iroquoian agronomic practices. Our results also indicate the potential value of obtaining δ 15 N values on archaeological maize in the investigation of Native American agronomic practices. OPEN ACCESS Citation: Hart JP, Feranec RS (2020) Using Maize δ 15 N values to assess soil fertility in fifteenth-and sixteenth-century ad Iroquoian agricultural fields. PLoS ONE 15(4): e0230952. https://doi.org/ 10.Groups using the mounding system in northeastern North American included Iroquoian language family speaking peoples in present-day New York, USA, and Ontario and Québec, Canada. From the fourteenth century AD onwards, Iroquoians lived in villages and towns that were occupied for 20 to 40 years or more [9] and housed hundreds to well over 1,000 individuals [10][11][12]. A major source of calories for these communities derived from agricultural produce, primarily maize (Zea mays ssp. mays) [13], but also other crops, including common bean (Phaseolus vulgaris), squash (Cucurbita pepo), and sunflower (Helianthus annuus) [14]. Non-cultivated foods included a wide range of terrestrial animals and plants [14,15], but with freshwater fish being an important source of animal protein for at least some populations [16,17]. The only domesticated animal present was dog (Canis lupus familiaris), which was consumed occasionally at feasts and ceremonies [18].The typical seventeenth-century AD ethnohistorically documented Iroquoian agricultural field consisted of many small mounds measuring approximately 46-120 cm in diameter and spaced 76-180 cm apart, which were formed with wooden, bone, antler, or stone hoes ([18], p. 178). Each mound contained 3-4 maize plants [18]. Common bean vines often were grown in the same hills with maize whose stalks acted as climbing poles for the bean vines, while squash vines were planted at intervals and occupied spaces around the mounds [19,20]. These fields were highly productive with some estimates suggesting they surpassed that of contemporaneous European and Euro-American farms [21]. While t...

Effects of marine biofertilisation on Celtic bean carbon, nitrogen and sulphur isotopes: Implications for reconstructing past diet and farming practices

“… Animal foddering: many domesticated animals are fed on a variety of agricultural crop by‐products 94 . This study has shown that all components of the plant are enriched during biofertilisation and not just the human‐consumed part of the plant. There is very strong evidence for fish fertilisation in North America 95 ; therefore, it may be worth considering its impact on ancient farming practices and palaeodiets in this region of the world. During the Medieval period there was increased reliance on the use of marine resources in different areas of the world, such as north‐west Europe 96 and the North Atlantic region 97 . Therefore, biofertilisers such as seaweed and fish (as products of domestic rubbish) may have led to a general increase in δ 15 N and δ 34 S value around agricultural or urban settlements compared with more inland communities.…”

Are Dogs Suitable Proxies for Humans in Archaeological Isotopic Dietary Assessments? Bayesian Analyses of Bone Collagen Stable Isotope Ratios from Ancestral Iroquoian Sites

“…and then offsets from [46] were added to each of the human ratios (S2 Table 1, online). Maize δ 13 C and δ 15 N were taken from [50]. Mann-Whitney and Epps-Singleton statistical tests were done in PAST version 4.11 [51].…”

Human and dog Bayesian dietary mixing models using bone collagen stable isotope ratios from ancestral Iroquoian sites in southern Ontario

“…To obtain δ 13 C and δ 15 N estimates for human feces, the TEF (5 for δ 13 C, 3 for δ 15 N) was subtracted from and then offsets from 47 were added to each of the human ratios (S2 Table 1 , online). Maize δ 13 C and δ 15 N were taken from 49 . Source means and concentration values are provided in S2 Table 6 , online.…”