¬The Advantage of Subsurface Drip-Tape Irrigation on Tomatoes Production under Different Irrigation Managements

Pressurized irrigation systems are most economical irrigation that use sufficient amount of water¡ fertilizers and other agricultural chemicals at proper time. Given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. Today¡ process improvement¡ development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. Attention to international dimensions of water scarcity especially in arid and semi-arid regions of the world¡ the latest recommendation of the International Commission on Irrigation and Drainage (ICID) in 8th Micro-irrigation Congress which has been held on 2011 in Iran¡ was development of subsurface micro-irrigation methods as a global orientation. Recently¡ due to existence aridity and accruing several droughts in Iran¡ Subsurface drip irrigation system has been considered by farmers¡ experts and researchers. This study was conducted to determine the impacts of¡ drip irrigation method and different amount of water and their interactions on yield¡ water use efficiency (WUE) and quality characteristic of tomato (Mobile cultivar). Experimental design was randomized complete blocks (RCBD) in split split plot with three replications. Design treatments included different amount of water (60¡ 80 and 100% water requirement) in main plot¡ drip irrigation method (surface and subsurface) in sub plot. The combined analysis showed that irrigation water amount¡ irrigation method and mulch treatments had significant effect on yield and WUE (P≤ 0.01). Yield in 60¡ 80 and 100% water requirement treatments was 31.141¡ 54.575 and 62.265 ton/ha¡ respectively¡ which showed significant difference. The highest WUE (7.881 kg/m3) was in 80% irrigation treatment¡ followed by 60 and 100% (with 5.925 and 7.232 kg/m3)¡ respectively. There was significant difference between yield in surface and subsurface drip irrigation (that was 43.380 and 55.274 ton/ha)¡ respectively. Water use efficiency in subsurface drip irrigation was 7.927 kg/m3 that was greater than surface drip irrigation. In this irrigation method; Soil evaporation¡ surface runoff¡ and deep percolation are greatly reduced or eliminated. Reductions in weed germination and weed growth often occur in drier regions. Infiltration and storage of seasonal precipitation can be enhanced by drier soils with less soil crusting. In some cases¡ the system can be used for a small irrigation event for use in germination¡ depending on dripline depth¡ flow rate and soil constraints. Entering the soil to the dripper is one of most important problems in development of the subsurface drip irrigation (SDI) system. This happens when the pump is turning off and it causes the dripper clogging. Dripper enveloping can decrease the problem. But there is anxiety about soil wetting patterns changing because of the use envelope.