The Early Agricultural period (EAP) has been a central focus of study in the American Southwest and northwestern Mexico for the past 30 years. This long interval, also considered as part of the Late Archaic in the greater region, comprises the introduction of maize agriculture and the development of sedentary agricultural communities over the course of more than 2000 years. Radiocarbon ages on maize indicate that maize was regularly cultivated by 2100 cal BC in the Tucson Basin; several recently dated specimens from the site of Las Capas suggest maize may have been grown here even earlier, between 2500 to 3700 cal BC. The shift from a mobile hunter-forager economy to a subsistence economy built around maize agriculture was long, and did not follow the trajectory of other agricultural societies world-wide; the Neolithic Demographic Transition in the Southwest was a slow process, prefaced by some 2500 years of agriculture, and did not occur simultaneously across the region. This dissertation comprises three articles that address the EAP in in southern Arizona. The first presents a review of the current status of research on the Archaic in the Tucson Basin, with a focus on the EAP and the past 30 years of work by both academic and Cultural Resource Management institutions. The second article places the EAP and development of agricultural communities in the context of Network Theory and Cultural Niche Construction theory; although regional populations were small, communities throughout northwestern Mexico and the Southwest US were connected by social and economic ties that facilitated the transmission of goods, information, and people, all of which were fundamental to the spread of agriculture and its associated societal consequences. The third article presents a chronological analysis of EAP sites in the Tucson Basin. OxCal is used to model the ages of 12 sites that date to the Silverbell interval and San Pedro phase; 160 radiocarbon ages, most obtained from carbonized maize, are used in the analysis. Temporal variation among sites and their locations along the Santa Cruz River floodplain are evaluated in light of changes in river geomorphology and the cumulative effects of community investment in agricultural infrastructure.

The development and establishment of agriculture in Northern Sweden has since long been believed to appear during the Late Iron Age, close to the Viking period, but recent finds from the Bronze Age in Umeå has opened up new discussion of when agriculture first emerged. Although too early to discuss where and when it developed, the material currently available on the topic allows for discussion for how it developed. By looking at sediment and soil conditions surrounding the settlements in combination with palaeoenvironments and past climate one aim was to try and search for settlement patterns in relation to agricultural potential, this was however unsuccessful. Cultivation practices were analysed using weed and wetland flora as well as agricultural indicators in pollen diagrams. Most settlements appear to focus firstly on animal husbandry and secondarily on cultivating crops, and they might have because of their coastal positioning also relied on fishing. The results confirmed previous hypothesis about the development of agriculture and cultivation practices in Northern Sweden during the Bronze and Iron Age, however, some issues remain concerning the lacking osteological material. / Utvecklingen och etableringen av jordbruk i Norrland har sedan länge verkat förekomma först under yngre järnåldern, nära vikingatiden, men nya fynd från bronsåldern i Umeå har öppnat upp diskussionen igen om när jordbruket först etablerade sig. Fastän det är för tidigt att behandla var och när, så tillåter det nuvarande materialet att börja till att diskutera hur jordbruket utvecklade sig. Kringliggande jordförhållanden har undersökts runtom bosättningar i relation till palaeomiljöer och forntida klimat med målet att söka efter bosättningsmönster i relation till potentialen att etablera jordbruk, men inga mönster framkom. Odlingsmetoder undersöktes genom ogräs och våtmarksväxter såväl som indikatorer på jordbruk och betning i pollendiagram. De flesta bosättningarna uppvisade ett fokus i första hand på djurhållning och i andra hand odling, samt att dess närhet till kusten och havet troligen såg ett utvecklat fiske. Resultaten bekräftade tidigare hypoteser om jordbrukets utveckling och odlingsmetoder i Norrland under Brons- och Järnåldern, dock återstår vissa problem beträffande det bristande osteologiska materialet.