The Tai migration heralded a new chapter in the history of Assam. The Tai Ahoms not only established a powerful kingdom in Assam, but also unified the whole of Assam politically, culturally and economically. The process was started in the 13th century itself when a branch of the Tais migrated to Assam and settled in the eastern part of the Brahmaputra valley under the leadership of Siu-ka-Pha. By the time they established their kingdom, the Ahoms had come to know about the fertility of the land of Assam and how favorable it would be for agriculture. They already knew how to grow wet rice through irrigation and terracing. They used animals like buffalo and ox to plough the land. The Ahom chronicles also refers to the agricultural superiority of the Ahoms over their neighbors.

                     At the time of the advent of the Ahoms, eastern Assam was occupied by the Morans and the Borahis. The Morans occupied the territory between the Burhi Dihing and the Dichang rivers. The Borahis were in the area between the Dichang and the Dikhow rivers. Their agriculture was still at its primitive stage and most of the lands remained uncultivated. They adopted shifting cultivation. The Ahoms found it easy to subjugate these tribes with their agricultural superiority. As agriculture was the main occupation at that time, agricultural superiority always played a crucial role when it came to territorial expansion.

                S iu-ka-Pha and his fellow Ahoms moved to the Brahmaputra valley in search of cultivable lands. The legend regarding their origin indicates that they had an objective, i.e. to pursue agricultural activity. As lands were remained fallow and wild in Assam at the time of their arrival, the Ahoms took special interest in agricultural development. During his journey, Siu-ka-Pha took interest in developing agriculture in Khamjang. He engaged his men in agricultural activities the areas he had conquered. He appointed officers to look after these men. After entering the Brahmaputra valley, he had changed many places due to factors like flood were affecting agriculture. Charaideo was chosen as it was a high place and the adjacent area was suitable for agriculture. He examined the soil throughout his journey and did not stop until he found the soil that suited his method of agriculture, which was wet rice cultivation. According to the Deodhai Asam Buranji, he selected Charaideo as his capital as he found the water of the Santak river flowing nearby was carrying much more alluvium than any other rivers.

                  After establishing the capital, Siu-ka-Pha established three big farms named the Barakhowa Khat, the Engerakhowa Khat and the Gachikala Khat in the suburbs of Charaideo for growing different varieties of Sali rice. The Gachikala Khat was assigned to supply provisions for the worship of the deities, Barakhowa Khat was assigned for ancestral rites of the king and the Engerakhowa Khat was for the royal household. The neighboring tribes of the Ahoms, the Marans and the Borahis had no such knowledge of agriculture. They lived in a wild territory and practiced shifting cultivation. Their population was estimated by the Ahoms to be four thousand people. Siu-ka-Pha handled with them diplomatically. He offered them his friendship. They accepted this and sent tributes to the Ahoms. The items of the tributes indicated that they did not have much knowledge of agriculture. Their tributes consisted of firewood, some edible items which were mostly gathered. The chronicles do not mention about any tribute from them in the form of rice. However, rice-beer has been mentioned. The Ahoms subjugated them easily. Siu-ka-Pha made matrimonial alliances with the two tribes. They began to supply the Ahoms with articles of daily need. He appointed some of them in royal household in different posts like changmai(royal cook). Since that time, there was an admixture of blood.

                  Siu-ka-Pha laid the foundation of the kingdom in a permanent footing. The introduction of wet rice cultivation brought about a radical change in the material life of the people. He acquired uncultivable lands and engaged local laborers to convert them into cultivable lands. The local people thereby learnt the process of wet rice cultivation. The local people were originally producers of ahu rice. This variety of rice suited the shifting cultivation. After three or four years, the ahu fields become exhausted and it remains fallow for several years. Moreover, ahu fields were easily accessible to wild animals as they were situated near forests and riverine belts. Another variety of rice, bao had some disadvantages also. The local people thus did not have surplus production. On the other hand, Sali, which was cultivated by the Ahoms, had some advantages. Sali fields are enriched by floods and it does not require labor after transplantation till harvesting. The Ahoms were better rice cultivators and they produced Sali rice on large scale. The introduction of Sali cultivation in Assam was a progressive trend in agriculture. It impressed the local people and they were also interested in learning wet rice cultivation. Siu-ka-Pha appointed these people in his royal farms or khats as serfs. The Assamese terms khatowal and bahatia stand for serfs attached to the farms.

                    One important community of that time, the Kacharis also cultivated ahu rice using slash and burn method. They knew how to irrigate and build dams. But they did not know how to plough the land. They did not confront with the Ahoms with hostility as they were also not stable and settled community at that time.

                 Gradually, Sali became the staple crop of the Ahom kingdom. They built a system of massive dykes and embankments. In this way, the flood water was controlled. The Ahoms took special interest in spreading the cultivation of Sali rice. The spread of wet rice cultivation was primarily responsible for the growth of population on the Ahom kingdom. The surplus production strengthened the economy. During Subinpha’s (1281-1293) time, the population was put under the king and the two great Gohains. They were instructed to supply the king with certain amount of their produce. The Ahoms considered land as a common property. Tax-free wet-rice plots were distributed to all the able male subjects. In return, they had to serve the kingdom. Thus, the kingdom was strengthened and the economy got a boost. The embankments built to prevent flood were serving as roads as well. Thus the Ahoms during the initial years of their newly found kingdom tried a lot to strengthen their position by expanding their progressive methods of cultivation and they were successful.

                         The migration of the Ahoms to Assam in the 13th century and the subsequent establishment of the Ahom kingdom had a far-reaching impact on the economy of Assam. The introduction of wet rice cultivation was a progressive step. The material life of the people changed as production increased. The 13th century thus is a benchmarking period of time for the economy of Assam. With their advanced agricultural system, the Ahoms had an edge over the communities living in Assam during the 13th century. Siu-ka-Pha, the founder of the Ahom kingdom, introduced wet rice cultivation and other communities also began to prefer it as it yielded more production. His successors gradually expanded the kingdom and more lands were brought under cultivation.

                          The introduction of Sali rice in Assam helped the Ahoms to multiply their population. They could subjugate the whole of Assam and became the sole ruler of the state. Later, the Ahoms could check the Muslim invasions because they had a strong economy. Thus we can see that the migration of the Ahoms to Assam in the 13th century had a deep impact on agriculture of Assam, which somehow was instrumental in changing the history of Assam.

References
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