Proposing an appropriate soil water content estimation technique

Shortage of water resources is one of the major limiting factors for agricultural development in semi-arid regions, e.g. Iran. Meanwhile, in recent years, Iran has been suffering from increases in water consumption and drought conditions; therefore, efficient use of irrigation water has become a key issue in agricultural production. One of the main aspects of water management in agriculture production is operating irrigation systems efficiently. A proper irrigation water management on-farm requires a routine monitoring of Soil Water Content (SWC). During the past decades, a substantial number of different experimental methods including, direct and indirect which are determined as well as ground based and remote sensing of SWC have been developed, and a large amount of theory and knowledge is now available for application. The need for indirect ground-based methods for obtaining water content or indices of water content is evident when the time and labor involved in direct sampling is considered. Selecting the best soil water measurement technology for optimal management of irrigation system in Iran is a great challenge for managers and decision makers. To propose an appropriate system in view of Iran conditions, besides technical parameters, region related parameters such as purchasing power and lack of technical knowledge of farmers, problems associated with after sale services and good performance in saline soils, are issues that must be taken into account. This article aims to (i) discuss the advantages and limitations of available ground based SWC measurement methods and, (ii) propose a technique that will best fit to conditions in Iran. Considering regional parameters of Iran, it was found out that the tensiometer is the most proper technique for efficient SWC measurement. This is a low cost technique and could be afforded by most farmers in Iran.