The southern Central Asian mountains as an ancient agricultural mixing zone: new archaeobotanical data from Barikot in the Swat valley of Pakistan

Abstract

The mountain foothills of inner Asia have served as a corridor of communication and exchange for at least five millennia, using historically documented trade routes such as the Silk Road and the Tea-Horse Road. Recent research has illustrated the important role that this mountain corridor played in the dispersal of crops and farming technology between northeast and southwest Asia 5,000 to 1,000 years ago. However, the role of the mountain valleys along the southern rim of the Pamirs and Himalaya in facilitating crop dispersals has not yet been fully explored. Notably, ongoing debates over secondary dispersals of Hordeum (barley) and Triticum (wheat) into China and the routes of dispersal for the East Asian crops Oryza sativa (rice), Prunus persica (peach) and P. armeniaca (apricot) into northern India are continuing topics of inquiry. In this article, we add to these discussions by focusing on archaeobotanical remains from the Barikot site (ca. 1200 bce–50 ce) in the Swat valley of northern Pakistan. The Swat valley is an ancient settlement zone in the Hindu Kush-Karakoram foothills, whose cultural features have always had a strong link with inner Asia. The archaeobotanical assemblage illustrates that a diverse array of crops, with origins across Asia, were cultivated around the same settlement. Additionally, these farmers likely implemented seasonal cropping cycles and irrigation that required various labour inputs and water management regimes.

Population-genomic analyses reveal bottlenecks and asymmetric introgression from Persian into iron walnut during domestication

“…Our results from population genetics thus match archaeological finds that suggest that Persian walnuts have been gathered and apparently traded by humans from the Late Neolithic onwards, judging from nut remains found in ceramic containers in an Armenian grave dating to ~6200 years ago [ 43 ], nutshells from Kashmir dated to ~4700–4000 years ago [ 44 ], and nutshells in a former market site from Pakistan dated to ~3200 years ago [ 45 ], and fully domesticated forms appear to have existed between ~4000 years (Middle Bronze Age) and ~2400 years ago (during the Classic era), which would have been before the principal functioning of the Silk Road from about ~100 AD onwards [ 46 ].…”

“…The early use of walnuts in this region is clear from nutshells found inside a ceramic container in an Armenian grave site (southern Caucasus) associated with C-14-dated remains from 4230 to 3790 BC (~6200 years ago, Late Neolithic) [ 43 ]. The Persian walnut’s anthropogenic expansion eastwards could thus have occurred already during the early Bronze Age (5300–3100 years ago) as indicated by nutshells found in Kashmir near C-14-dated wheat and barley grains from 2700 to 2000 BC (~4700–4000 years ago) [ 44 ] and in northern Pakistan in soil below a market, with other C-14-dated remains from 1200 BC (~3200 years ago) [ 45 ]. The fossils’ presence below a former market suggests that these walnuts were actively collected and traded.…”

A Journey to the West: The Ancient Dispersal of Rice Out of East Asia

“…Recent genetic studies also suggest long periods of population continuity in rich mountain valleys, notably the Swat Valley (Narasimhan et al 2019). Despite a lack of evidence for human genetic movements through the southern Himalayan valleys, there is considerable evidence for the movement of goods and crops (Spengler et al 2020). Discussions of crop dispersal in this region are often closely linked to the concept of a "Northern Neolithic", suggesting that a unique developmental trajectory was followed by farmers in Swat and Kashmir (Betts et al 2019).…”

“…An intensive and complex agricultural system was recently identified at the multiphase site of Barikot in the studied period (ca. 1200 BC-50 AD) in the Swat Valley (Olivieri et al 2019), whereas rice was likely a summer crop in a mixed cropping system (Spengler et al 2020;Fig. 2h, j).…”

Prehistoric agricultural decision making in the western Himalayas: ecological and social variables

“…Crop diversification increased through time, with the introduction of rice, horse gram (Macrotyloma uniflorum), and multiple types of fruits and millets during the Kushan period (AD 30-375) (Pokharia et al 2018). Ancient farmers in the Swat, Ganges and northern Indus valleys, near the Himalayas, also cultivated an array of crops at least as far back as the early second millennium BC (Constantini 1987;Boivin 2017;Petrie & Bates 2017;Pokharia et al 2018;Spengler et al 2020).…”