การเปลี่ยนแปลงของนาน้ำลึกสู่การผลิตข้าวนาชลประทาน: สถานการณ์ปัจจุบันและความท้าทาย

Abstract

“Transition of Deepwater Rice to Flooded Rice System: Current Situation and Challenge” research was conducted within 14 sub-districts in Prachin Buri and Chachoengsao Provinces, during 2009 to 2010. The overall objectives of the research were to find out the current situation transition of deepwater rice to flooded rice system, and to define appropriated technology for flooded rice production in this area. System approaches including soft and hard system methods were employed to conduct the research. Four hundred and two households were interviewed to inquire the current rice production situation. Field experiments were conducted to find out alternative management for flooded rice production. In addition, CERES-Rice model, a process-oriented crop model, was evaluated for application in the transitional phase to flooded rice production in deepwater area. The research found that eighty four percent of farm-households in the study area had been transformed to flooded rice production system. The significant reasons for the transition were higher rice yield and shorter growth duration of flooded rice as compared to deepwater rice. The information sources for the farmers for plating date selection, variety selection and fertilizer management from most to least significant were neighbor, neighbor and trial an error, trial an error, government agency, and neighbor and government agency. A series of field experiments was conducted and founded that flooded rice production in early rainy season, PSL2 variety gave the highest averaged yield over four planting dates of 3.9 ton ha-1 which was not significantly different from PTT1 variety, with an average yield of 3.8 ton ha-1. While flooded rice production in dry season, PTT1 variety planting at November 9 gave the highest yield with an average yield of 3.7 ton ha-1. The Leaf Color Chart (LCC) technique with broadcasting was appropriate nitrogen fertilizer application management for flooded rice production systems in the deepwater area. GENCALC and GLUE estimators, which included in DSSATv45 crop model package, could be used to estimate rice genetic coefficients. Overall evaluation concludes that simulated output of development, growth, yield, and leaf N concentration of flooded rice was good compared to field recorded. Even, it overestimated of top weight biomass and caution was needed to estimate of this parameter. However, the model gave good estimate to changes of rice variety, planting date, and nitrogen application rate. Therefore the CERES-Rice model could be use to simulate and assess flooded rice production in deepwater area for testing the alternatives before making decision to improve the system.