Assessment of Irrigation Management of a Pistachio Garden in Ardekan Using Time-domain Reflectometer (TDR) and Remote Sensing Technique

One of the methods of understanding and evaluating the irrigation management is to measure soil moisture, plant indices and vegetation temperature. The present study aims to introduce a traditional pattern of irrigation management (continuous water rotation in an irrigation zone) in the pistachio gardens of Ardakan, and evaluate its strengths and weaknesses. A TDR device was used in a one-month period in order to study the daily changes of the soil moisture. To do this, soil moisture was measured on a daily basis in four different depths in 25 points of the studied land. Moreover, Landsat satellite images were used to determine the normalized difference vegetation index (NDVI), and vegetation coverage temperature, and the results were compared to those of the neighboring pistachio gardens. The results showed that the average soil moisture of the studied land in 25 points were approximately the same in all days and is in a range of 15 to 20 volumetric percent (with the average of 17.6 percent and the standard deviation of 3.6 percent). This pattern caused a favorable microclimatic condition and proportional reduction in drought effects in pistachio gardens which is beneficial to the plants. Furthermore, the NDVI and vegetation temperature indices showed a better condition in the studied Pistachio garden in comparison with the neighboring gardens which is a result of management pattern. Promoting the aforementioned method of irrigation, (continuous water rotation in an irrigation zone and irrigation of scattered and distinct parts) – and applying it in other pistachio gardens –where irrigation starts in one part and goes through adjacent parts in a row to irrigate all the land_ is one of the achievements of this study.