The Effects of Irrigation Methods and Water Quality on Soil Chemical Properties and Leaf Nutrient Uptake of Lavandula (Lavandula angustifolia L.) in an Arid Region

In order to investigate the effect of wastewater on the soil minerals movement, irrigation water use efficiency (IWUE) and leaf nutrients uptake of medicinal-industrial-landscape Lavandula (Lavandula angustifolia L.) by two types of irrigation systems, the experiment was performed as a factorial experiment in a randomized complete block design with three replications. Experimental treatments were included quality of irrigation water (fresh water and treated wastewater) and irrigation method [surface irrigation (SI) and subsurface irrigation with permeable tubes (SSI)]. Soil samples were collected at the end of the experiment for each treatment at depths of 0-15, 15-30 and 30-60 cm to analyze Electrical Conductivity (EC), phosphorus (P), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and total nitrogen (N). Plots were irrigated with treated wastewater by SSI method showed fresh and dry weights of canopy higher than irrigation with fresh water by SI method. The results suggested that contrary to IWUE, water quality was more effective than irrigation system on the wet and dry weights of the canopy and leaf nutrients uptake. Based on the results, SSI method with treated wastewater increased the IWUE by 64% compared to SI method with fresh water. The highest and lowest IWUE were obtained by application of the treated wastewater (0.44 kg m(-3)) and the fresh water (0.25 kg m(-3)), respectively. The higher levels of most minerals, including N, Ca, Mg, Na, K and P, were recorded when plots were irrigated by SSI system and received treated wastewater. The subsurface irrigation created significantly higher EC, Na, Mg and Ca compared to the surface irrigation in the topsoil. The EC, K, Mg and Na of second and third soil layers that received the wastewater were less compared to the fresh water. No significant effect on soil N, P and Na was observed in all three depths of soil due to application of the wastewater for irrigation.