APPLICATION OF BRACKISH WATER IN SUBSURFACE DRIP IRRIGATION SYSTEM ON PISTACHIO ORCHARDS

摘要

Irrigation systems with higher efficiencies such as microirrigation systems are developingrnsince last decade to achieve higher water use efficiency. At the same time, quality ofrnwater is decreasing in those areas due to overwithdrawal from the water resources. InrnKerman province, the salinity of water increased to more than 10 dS/m in some arearnmainly due to water overwithdrawal. Therefore, application of saline water for irrigation ofrnpistachio orchards is now inevitable, which contributed to increase in salt accumulation inrnsoil surface and soil degradation. The main purpose of this study was the use of salinernwater in subsurface dripirrigation system (SDI) of pistachio orchards. The research wasrnconducted during 2005-2008 on 12 year old pistachio trees. The drip-lines with selfcleaningrnand pressure compensating drippers were placed in two depths of 50 and 70 cmrnbased on the fertilizer channel depth for pistachio trees. Emitters flow rate was 3.6 l/hrrnand 75 cm apart. Treatments consisted of two drip-line depths, and three irrigation levelsrnof 100% (I_1), 75% (I_2) and 50% (I_3) of pistachio water requirements, with threernreplications, based on a completely randomized block experimental design. Salinity ofrnirrigation water was 8.1 dS/m and irrigation water was applied in a 10 day - interval.rnAccording to the results, there was no significant impact of irrigation water treatment onrnpistachio yields. Annual applied irrigation water for I_1, I_2 and I_3 was 2050, 3065 and 4010rnm~3/ha and water use efficiency of pistachio was 1.1, 1.2 and 2.0 kg/m~3 respectively.rnPistachio quality characteristics improved compared with pistachio trees irrigation by arnsurface irrigation system. Salinity increased near the soil surface by decreasing in depthrnof drip-line setup.