A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Agricultural Systems and Engineering, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 2017

The experiment was conducted at ASE greenhouse, AIT, Thailand. The objective of this research was to assess the effect of different rates of potassium under two methods of cultivation (direct seeding and transplanting) on three rice varieties (Pathumthani-1, RD57 and RD41). Four rates of potassium oxide (0, 80, 120 and 160 kg/ha) was applied in both methods of cultivation (direct seeding and transplanting). Potassium fertilizer had highly significant on plant height, productive tiller, non-productive tiller, number of panicle, filled grain, 1000-grain weight, and grain per panicle and yield. Therefore, by addition of 80, 120 and160 kg/ha potassium fertilizer total yield increased by 28.6%, 46.8% and 37% ; 40.3%, 23.6% and 49.5% ; and 31.3%, 39.8% and 29.6% in Pathumthani-1, RD57 and RD41 varieties, respectively, than the control. Although, in this study the effect of cultivation methods, verities and water productivity were observed significantly effect on the most of parameters. In conclusion, by application of potassium fertilizer the total yield of three rice varieties increased in both methods of cultivation.