Integrated of Soil and Water Conservation Planning in Moungphlong Subwatershed, Amphoe Phanom Sarakham, Chachoengsao   Sathaporn Jaiarree   ABSTRACT         The study on integrated soil and water conservation planning was implemented in the area of Moungphlong . Village, Tambol Khaohinsorn, Amphoe Phanom Sarakham, Changwat Chachoengsao which is under the implementation of Khao Hin Sorn Royal Development Study Center.This study aimed at solving the problem of soil erosion and inappropriate irrigation which were problem of farmers in area. The research was during October 1987 - September 1990. The total area of the study was 514.5 rai. The collected data included physical characteristic of the area for examples ; soil characteristic , hydrological data etc. Through the data of socio-economic condition and these data were analyzed and used to formulate the integrated conservation plans. Four conservation plans, namely simple, intermediate, intensive and implement were established for the study area which each plans had different objective and practical. Simple plan was easy to practice and cheap plan. Agronomic conservation measures were emphasized on this plan. Intermidiate plan was emphasized on intensive of soil and water conservation system which contained agronomic and mechanical conservation measures for efficient of soil erosion control. Intensive irrigation system would be addition for intensive plan which was integrated of cropping system, conservation system and intensive irrigation system. For implement plan was applied to suit in the farmer's area. Each conservation plan was evaluated for erosion control and socio-economic feasibility.       The results of this study revealed that 76.68 percent of the total area was affected by moderately soil erosion (5-20 ton/rai/year). For crop land suitability classification, annual crop had suitable for Mab bon soil series and not suit for the fruit trees. However, after improving soil compact layer, fruit trees could be introduced to implement in the area.The Universal Soil Loss Equation (USLE) was used to evaluate the rate of soil loss for each conservation plan the results disclosed that when four conservation plans were operated on the study area, the rate of soil loss would be decreased to 75.36 97.61 97.61 and 96.66 percent for simple, intermediate, intensive and implement plan respectively for young fruit trees, as compared with that without conservation plans and to 86.64 98.33 98.33 and 97.77 percent respectively for the future.For economical evaluation, the results of analysis revealed that the Net Present Value (NPV) were 3,483.559 21,104,379 21,177,252 20,458,860 and 11,911,422 baht for without conservation, simple, intermediate, intensive and implement plan respectively and the Benefit Cost analysis (B/C ratio) was 1.79, 2.33, 2.36, 2.25 and 2.25 respectively.       Base on socio-economic feasibility study, through technical study, it was revealed that the implement plan was likely possible to be accepted by farmers and technicians. However, in the future when the agricultural technology is developed, the intensive plan may be good plan for soil and water conservation plan.         Keywords: Soil and water conservation planning