Evaluation of shallow groundwater contribution by two lentil cultivars water use

Shallow groundwater is a resource which can provides and meets high values of plant’s water requirement. Shallow groundwater use by plant depends on different factors as: soil hydraulic conductivity, plant root features and characteristics, salinity tolerance level, a proper drainage system, irrigation system and management. In case of shallow groundwater use by plant, total irrigation number and water requirement will be reduced. Therefore, shallow groundwater, is a potential, efficient and free water resource in agriculture which sometimes defined as subsurface irrigation. The present study was conducted with the aim to examine the effects of shallow water table of 60, 80 and 110 cm depth on the water requirement, water use efficiency and different yield components of two lentil varieties namely that was conducted into two-factor factorial and based on completely randomized design with three replications. This research was carried out at Kermanshah with semi-arid climate by using lysimeters during two growing season 2013 and 2014. The research was performed at the Irrigation and Water Resources Engineering Research Lysimetric Station, located at 47°9′ E and 34°21′ N, with an elevation of 1319 m (asl), as a part of the Campus of Agriculture and Natural Resources of Razi University in Kermanshah, Iran. In this study 18 Polyetelen lysimeters with diameter of 280 mm were used. The bottom of lysimeters were blocked to prevent of any leaching. Groundwater levels in the lysimeters were determined and fixed by Marriott siphon that was installed beside of each lysimeter in different groundwater depths of 60, 80 and 110 cm. The soil texture in the lysimeters was Silty clay. The cultivation in the first and second year of the research was conducted in 13 and 16 March, years 2013 and 2014 respectively. To obtain the amount of water requirement of plants, evaporation data of pan class A was received daily from the meteorology station which was located at distance of one hundred meters from research station. In this research, water requirement was determined by considering three stages as: reference evapotranspiration (ETo), the crop coefficient (KC) and finally crop evapotranspiration. Analysis of variance and comparison of means were done for different treatment by MSTATC software According to the results in both years of study, maximum and minimum consumption of groundwater belong to depths of 60 and 110 cm, respectively. The ground water contribution for depths of 60, 80 and 110 cm was obtained as 53.76%، 36.50%، 15.23%, respectively. The results showed that maximum groundwater use efficiency, based on seed yield, for ILL6037 and Kimia cultivars was obtained in depths of 110, and the minimum groundwater use efficiency, for ILL6037 cultivar was obtained in depths 60 and 80 cm during both years of study, respectively. Also the maximum and minimum seed yield in both years of study was obtained for Kimia cultivar, in water table depths 60 and 110 cm respectively. Moreover, the maximum and minimum protein values was obtained, for Kimia cultivar in depth of 110 cm and ILL6037 cultivar in depth of 60 cm respectively. It can be concluded that by increasing the depth of water table the values of groundwater contribution to crop water requirement was reduced. It may reason of increasing the distance between plant roots and water table. As a result of this phenomenon, plant root access to water by the use of capillary rise to meet the water requirement reduced and therefore, the groundwater contribution for providing plant water requirement was reduced. The results of this research showed that legume crops such as Lentil can use groundwater properly.