DEVELOPMENT OF LOW COST SOIL MOISTURE SENSOR AND WIRELESS SYSTEM NETWORK FOR CROP IRRIGATION IN GIS
Mr. Sibghat Ullah and Dr. Javed Iqbal
Pakistan is water scarce country, with limited water resources. About 96% of the total available water is used for agricultural purposes, leaving 2% for domestic and another 2% for industrial use. The agriculture sector contributes about 25% of the Pakistan's GNP (2000-2001). Farmers in Pakistan receive their share of irrigation waters on a rotational basis. To protect the right of share of their water, the farmers are using more than the optimum quantity of water required for healthy crops. Due to lack of modern irrigation techniques most of the farmers use the flood (surface) irrigation system which is waste of the irrigation water. The use of modern techniques of irrigation system which could be tailored according to the requirements of different soils and crops could save water. This could be achieved through accurately making the decision as to when, how much, and where to apply irrigation water according to the needs of soil/crops. Wireless sensor networks are a promising new in situ soil moisture measurement technology with a high spatial and temporal resolution for large areas. However, to realize sensor networks at the small basin scale (e.g. 500 sensors for an area of 25 ha), the costs for a single sensor have to be minimized. The decision making process could not be achieved manually with a high spatial and temporal resolution. Commercially available soil moisture sensors and the accompanied wireless network components in the market are very expensive and beyond the reach of the farming and academic communities in Pakistan therefore the major objective of this study was to develop indigenous low cost soil moisture sensor and assemble wireless network that can be affordable and could be used in scheduling the time and amount of irrigation water required. A Wireless Sensor Network (WSN) consists of spatially distributed transceivers for monitoring, collecting and storing data. In this study a set of indigenous soil moisture sensors and accompanied network has been designed and developed. A spatial decision support system (SDSS) has also been developed to wirelessly turn on/off the sprinkle irrigation system according to the soil moisture content. The development of this indigenous variable rate wireless irrigation system will not only save irrigation water but will also save foreign exchange for Pakistan.