## 1 Introduction  
Turkey is an agricultural country. Turkey and many similarly agricultural countries have great problems in the irrigation process due to a scarcity of water resources. Although major changes and improvements have been seen in Turkey's agricultural policies, the overconsumption of water resources exacerbates the problem. The export situation resulting from the plants grown and influencing the quality directly reveals the importance of water consumption [1]. The agriculture in Turkey needs more assistance for farms and farmers, more advanced research in recent available agricultural technologies, more automation, and more testing and applying new methods of study, analysis, and mechanization. The soil moisture sensor measures the amount of moisture in the soil. The measurement is done by immersing probes on the sensor. The depth of measurement may vary depending on the plant species. This means that the probes are close to the root of the plant. The working principle of the soil moisture sensors is that there is a voltage difference between the tips of the probes due to the resistance of the soil. Increasing the amount of moisture (wetness) in the ground increases its conductivity. Thus, the amount of moisture is measured according to the magnitude of the voltage difference. The requests to use information technology to a larger extent in irrigation systems are increasing by the day. Many technological methods are used in irrigation systems [2; 3; 4; 5; 6]. When these methods are considered, using smart phones and tablets has become widespread. Becoming a small computer system, wireless and portable structure, operating fast and having the wide memory capacity are important factors to spread the use of these devices. These factors make the use of mobile devices attractive for many applications such as environmental controls, health service monitoring, security, transportation and automation [7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25]. This paper studies the application of Precision Irrigation (PI) using sensor network technology (SNT), which emerged as a management practice with the potential to increase profits by utilizing more precise information about agricultural resources through sensing and communication technology in Turkey and takes the crops as a specific example for investigating a possible PI solution using Sensor Network Technology (SNT) integrated with IOS/Android application. The application is an automated agricultural irrigation system, which is controlled on mobile devices based on IOS/Android and is capable of monitoring the irrigation levels. The mobile device software was defined as agRapp. The system measures the water quantity of the soil via sensors placed at different points near the roots of products and transmits the data via PLC to mobile devices. Thus, the operating status of the irrigation system is defined according to the water level inside the soil. The most important property of this study, which differentiates it from previous studies, is defining the required water level by product depending on growth stages. Initially, during crop development, mid-season and late season stages, the system defines the required water level through developed software. Moreover, alternative energy resources are used to meet the required energy level. It has already been known that solar power reduces the energy cost [26; 27; 28; 29; 30; 31; 32], therefore solar power was used in this study. Today, using water efficiently in agricultural irrigation systems is very important. Although this situation may lead to the development of different irrigation systems, it is still necessary to increase the efficiency. For this reason, the development of an irrigation system that takes into consideration the periodic water needs of the plants as well as the water condition of the soil gains great importance. In addition, the plant's water need should be monitored continuously, not instantaneously.