www.tjprc.org editor@tjprc.org DEVELOPMENT OF LOW COST FARMER FRIENDLY SENSOR FOR RICE WATER MANAGEMENT R. NAGARAJAN 1 & BASAMMA ALADAKATTI 2 1&2 Department of SWE, TNAU, Coimbatore, Tamil Nadu, India ABSTRACT Rice is the major consumer of water among all agricultural crops accounting about 70 – 80% of total agricultural crop water needs. The irrigation method and water requirement at different crop growth stages largely dictates the quantum of water to be applied for rice production. Though studies were made to apply accurate measurement of water through sensor but they are not adopted by farmers due to various economic and operational constraints. A study was conducted to develop a low cost farmer friendly sensor for rice water management. The study focused the fabrication of water level sensor and testing it under laboratory and field conditions. The sensor was tested and it was linked with a commercially available automation unit for accessing its functional performance. The water level sensor was developed on the principle of floatation and buoyancy. In laboratory condition, the water level sensor was calibrated for the selected lever type micro switch using plastic square tray of size 17 x 17 cm. The preliminary testing of developed sensor with commercially available automation unit developed by EMRAL Tune Line Private Limited was done to evaluate the performance of the water level sensor under laboratory conditions and it was found that the sensor was working properly with the linked automation unit. The water level sensor for two different standing depths namely 2.5 cm and 5.0 cm were tested under field conditions in two locations of Tamil Nadu Agricultural University: (i) Wetlands and (ii) Eastern block farm. At each field location, the sensor was tested in the plot of size 3m x 3m and the depth of water above the land surface at the centre of the plot and at the four corners of the plot and the time taken for draining of water was also observed. At each field location, three trials were conducted for each standing water depth. The water depth at the centre of the plot did not vary so much but at the corners of the plot there was a minor variations (<5mm) in depth of water. The variations were mainly due to improper leveling of field. The water level sensor was simple, precise, easy to handle and low in cost. The cost of water level sensor is Rs. 200. The developed water level sensor for 5.0 cm, 2.5 cm depth of water and 0 cm (for disappearance of water) which could be used in rice water management. There is a high scope of further optimization of water level sensor where a single float should be used for all desired water depths for different types of lever type micro switch. This could enable the quantum of water and labour saving through sensor based irrigation. KEYWORDS: Rice, Major Water Consumer, Economic and Operational Constraints, Floatation and Buoyancy Received: Apr 21, 2016 Accepted: May 10, 2016; Published: May 21, 2016; Paper Id.: IJASRJUN2016033 INTRODUCTION In Asia, rice is not only the staple food, but also the major economic activity and the key source of employment and income for the rural population. In south Asia, rice based cropping systems account for more than half of the total acreage, where rice is grown in sequence with rice or upland crops like wheat, maize or legumes. Water is the single most important component for sustainable rice production, especially in the traditional rice growing areas of the region. Rice is the major consumer of water among all agricultural crops which accounts about 70 – 80% of total agricultural crop water needs. Reduced investments in irrigation Original Article International Journal of Agricultural Science and Research (IJASR) ISSN(P): 2250-0057; ISSN(E): 2321-0087 Vol. 6, Issue 3, Jun 2016, 273-282 © TJPRC Pvt. Ltd.