COMPARISON OF REAL TIME SPRINKLER IRRIGATION SCHEDULING BASED ON SOIL MOISTURE SENSOR, SPRINKLER IRRIGATION AND FLOOD IRRIGATION OF WHEAT IN VERTISOLS

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1 Comparison of Real Time Sprinkler Irrigation Scheduling Based on Soil Moisture Sensor Proceedings of AIPA 2012, INDIA 283 COMPARISON OF REAL TIME SPRINKLER IRRIGATION SCHEDULING BASED ON SOIL MOISTURE SENSOR, SPRINKLER IRRIGATION AND FLOOD IRRIGATION OF WHEAT IN VERTISOLS R.C. Singh, C.D. Singh, K.P. Singh and Ramadhar Singh Central Institute of Agricultural Engineering, Nabi Bagh, Berasia Road, Bhopal ABSTRACT An investigation was undertaken to determine the effect of soil water and rooting depth monitoring of winter wheat on irrigation water saving. Two independent experiments were conducted in a split plot design for winter wheat for three irrigation methods with three replications in a vertisols. The irrigation systems were real time sprinkler irrigation scheduling, sprinkler irrigation and conventional irrigation methods. A significant improvement in water saving was obtained with irrigation methods in which irrigation requirements were based on soil water and rooting depth monitoring comparing to conventional irrigation method that was based on a fixed irrigation interval. The experimental results indicated that a significant improvement in water saving also was observed when irrigation scheduling was based on real time soil moisture based monitoring comparing to the fixed interval of sprinkler irrigation for water requirement. The irrigation water use efficiency using the sprinkler system was higher compared to the flood and furrow irrigation methods which indicate that if you are trying to conserve water, then a sprinkler irrigation system should be used with some form of irrigation scheduling. Keywords: Irrigation Scheduling, Water Saving, Soil Moisture Monitoring, Root Depth Monitoring. 1. INTRODUCTION The Vindhya platue is one of the main food production regions in Madhya Pradesh, India. With increasing concern about declining water resources, there is a great intension to improve water management in farming systems to improve water saving.(buttar et al., 2007). Several possible approaches such as irrigation technologies and efficient irrigation scheduling (Kirda, 2000) may be adapted for more effective uses of limited water supplies. The great challenge of the agricultural sector is to produce more food from less water, which can be achieved by increasing crop water productivity. Irrigation scheduling is the process by which an irrigator determines the timing and quantity of water to be applied to the crop/pasture. To avoid over or under watering, it is important to know how much water is available to the plant, and how efficiently the plant can use it. Water scarcity limits food production in this region, increasing water use efficiency is necessary to maintain high-level food production. Since sprinkler irrigation has the potential for improving water use efficiency and grain yields, it is increasingly being used in this region. Proper scheduling of sprinkler irrigation is critical for efficient water management in crop production, particularly under conditions of water scarcity (Pereira et al., 2002). The objective of this paper is to evaluate the effect of soil water monitoring on water saving comparing with conventional irrigation method and compare real time sprinkler irrigation scheduling, sprinkler irrigation and flood irrigation of winter wheat and their effect on yield and crop canopy in the vertisols. 2. MATERIALS AND METHODS Three irrigation experiments were conducted. The first sprinkler irrigation experiment was conducted over 2 years (2010 and 2011) at the Central Institute of Agricultural Engineering, Bhopal. The soil was a vertisols. Wheat was row shown in 1.83 m wide (five rows in 2009 and six rows in 2010) parallel to the sprinkler line-source. Dates of sowing were 9 November 2009 and 15 November To ensure wheat germination, all plants were irrigated uniformly using a solid-set sprinkler irrigation system at a rate of cm per day from the sowing date to 20 November during each growing season. The layout of the field experiment is shown below: To carry out study, two fields B-5 and B-6 of CIAE farm were selected considering security, vicinity of irrigation water source, and easy accessibility to site. Layout of field experiments was carried out as per experiment treatment details and is shown in Figure 1. The field experiment consists of four treatment viz. Soil moisture-dss based automated sprinkler irrigation system, Timer based automated sprinkler irrigation system, conventional sprinkler irrigation system and flood irrigation system. The experiment was laid following block randomized design with 4 replication of each treatment. The area under each treatment is 0.3 ha. The RCC tank of 100 m 3 capacity was constructed to have

2 284 Agro-Informatics and Precision Agriculture 2012 (AIPA 2012) independent water supply for this automated sprinkler irrigation system. One control room of 6 m 4 m size in B-7 field was constructed for control panels for 5 and 10 HP 3-phase starter with energy meters and SCADA based DSS system. 7.5 HP and 10 Hp open well submersible pump sets, electrical control panels comprising energy meter, 3 Phase starter, Single Phase protector, Ammeter, Voltmeter for 5 and 10 HP pump sets have been purchased and installed. The sprinkler Irrigation system (Make: Jain Irrigation Ltd.) with water meters was installed per experimental layout and testing in the field. Fig. 1: Layout of Field Experiment 2.1 Telemetry Based Real Time Sprinkler Irrigation Scheduling Based on Soil Moisture Sensor A telemetry based real time sprinkler irrigation scheduling based on soil moisture sensor has been installed in B-6 field. The block diagram of the system design is shown in Figure 2. Fig. 2: DSS and Telemetry System for Field Irrigation The network starts with a soil moisture sensor (MP406), an air temperature sensor grouped together in a data logger (Smart logger, Model SL5-1L, 200 channels, ICT International, Australia. Each zone had one Standing Wave Soil Moisture Probes (MP406 Soil Moisture Sensor used to measure volumetric soil water content) (SMP). These sensors are connected to radios which are programmed to send data back at designated intervals to a radio base station (Instrumentation Cell) to receive signals from the outlying radio field stations. The network is designed in such a way that

3 Comparison of Real Time Sprinkler Irrigation Scheduling Based on Soil Moisture Sensor 285 any future expansion of new sensors will be accommodated. The cable leads of all four sensors were connected to an SMD4-P smart interface (ICT International), which in turn was connected to the data logger at the field edge (Figure 1). The soil temperature (Model TM4, ICT International) was also monitored and was used to correct the SMP calibrations. The data logger was programmed to monitor the soil moisture and controlled the irrigations for each zone individually. The Smart data logger was programmed to make irrigation decisions every 12 hours. Zones were irrigated for 8 hours if the SMP threshold was exceeded. The data logger controlled the irrigations using an SMD4-P controller (ICT International) to which the solenoid valves at each zone were connected. The data logger was powered by a solar panel and the controller was powered by 24 V AC. It not only stores all the information coming in, but controls how often the readings are made and transmit data to desktop computer (Instrumentation Cell) through telemetry system. Data logger is connected to a modem which downloads the information using the mobile phone network (AirTel) onto a ftp server. Specialist software, some of which has been developed for data downloading through telemetry, archives and manipulates the data and presents it for prediction for irrigation scheduling. A solar panel for power monitor has been installed to give continuous power source to data logger and modem. A range of water, soil and temperature parameters can be monitored using sensors linked to the developed telemetry network. 3. RESULTS AND DISCUSSIONS 3.1 Field Experiment on Wheat under Flood Method of Irrigation Field experiment on water saving and water application efficiency in conventional surface irrigation (flood method) was carried out during Rabi for wheat crop (variety HI-1544) in field B-4 of Institute farm respectively (Figure 3). The recommended doze of NPK (10:50:30) kg/ha were applied and cultivation practices of mechanized farming for wheat crop in vertisols were adopted. Fig. 3: Wheat Crop under Flood Method of Irrigation The irrigation was provided at 30 days interval considering scarcity of irrigation water. Crop performance parameters (Plant growth attributes i.e. plant population and plant height)) were recorded at 15 Days after Sowing (DAS) interval. Crop yield attributes and gain yield values were also obtained. The depth of irrigation applied was 10 cm for flood method of irrigation. The quantity of irrigation water applied, water application efficiency, crop yield and water use efficiency obtained under flood irrigation method is given below: Sl. No. Particular Flood Irrigation (Control) 1. Quantity of water applied (m 3 ) Water application efficiency (%) Crop yield (t/ha) Water use efficiency (Kg/ha/mm) For Flood method of irrigation water application and water use efficiencies were found to be kg/ha/mm of water in vertisols. The DSS based real time sprinkler irrigation scheduling based on soil moisture sensor is shown in Figure 4.

4 286 Agro-Informatics and Precision Agriculture 2012 (AIPA 2012) Fig. 4: DSS Based Real Time Sprinkler Irrigation Scheduling in Real Field The soil moisture sensors (MP406) were installed at 15 cm depth and 30 cm depth in irrigated wheat crop field of Institute farm during third week of January The real time soil moisture data recorded at 6 hour interval by the sensors for the period (16/01/2010 to 15/02/2011) were transmitted effectively to a PC installed in Instrumentation Cell through transmitter and receiver using the mobile phone network (AirTel). To collect soil sample upto 15 cm and 30 cm depths, soil core sampler of 38 mm diameter and 35 cm length was used. The actual soil moisture of collected soil sample was determined using gravimetric method for calibration of soil moisture sensors. The soil moisture sensor was calibrated by comparing measured field soil moisture and recorded soil moisture through sensor. Soil moisture data collected through telemetry system has been calibrated with reference to oven method. The calibration curves for average values of measured soil moisture through telemetry and soil moisture data through oven method is shown in Figure 4. The results from measurement of absolute volumetric soil water per cent (VSW%) from field soil samples using telemetry with respect to oven method are given in (Figure 5). It has been found that collected soil moisture data are as per oven method for a vertisol. Fig. 5: Soil Moisture Sensor Calibration Curve In case of real time sprinkler irrigation scheduling significant water saving has been observed in comparison to flood and sprinkler irrigation scheduling. 4. CONCLUSIONS Irrigation efficiency under a sprinkler irrigated wheat field is going to be low as compared to using a real time sprinkler irrigation system and operating the system for maximum yield. However, economic analysis indicates that this is the irrigation management practice that should be followed by farmers until the cost of water increases considerably. Using a real time sprinkler system can increase yield and maintain a high Irrigation efficiency compared to flood and sprinkler irrigation. The irrigation water use efficiency using the sprinkler system was higher compared to the flood and furrow irrigation methods which indicate that if you are trying to conserve water, then a sprinkler irrigation system should be used with some form of irrigation scheduling. If you are trying to maximize yield, then this will be achieved by using a real time irrigation system.

5 Comparison of Real Time Sprinkler Irrigation Scheduling Based on Soil Moisture Sensor 287 ACKNOWLEDGEMENTS The writers are thankful to Director, CIAE, Bhopal for his constant encouragement and support. REFERENCES Panda, R.K., Behera, S.K. and Kashyap, P.S., 2004, Effective management of irrigation water for maize under stressed conditions. Agricultural Water Management. 66(3): Pereira, L.S., Oweis, T. and Zairi, A. 2002, Irrigation management under water scarcity. Agric Water Management 57: Singh, S., Ram, M., Ram, D., Singh, V.P., Sharma, S. and Tajuddin, 2000, Response of lemongrass (Cymbopogon flexuosus) under different levels of irrigation on deep sandy soils. Irrig Science 20:15 21.