Deficit irrigation is a strategy which could be applied to utilize water efficiently. The goal of the article was to review and examine different irrigation deficit to compare its crop morphological characters, yield, water productivity and water use efficiency under different crop type. The overall idea and results are very actual and useful over the world in the semi-arid and arid area interms of water managment and better economic return per applied water.The maximum production in dryland, tomato should be irrigated using drip irrigation system with 100%ETc watering amount [17]. On the other hand 85%, 75% and 30% are also effective in terms of water saving and yield. 85%ETc irrigation level water applied system appears to be a promising alternative for water conservation and labor saving with negligible trade-off in yield of maize [15]. The application of deficit irrigation (75%ETc) could be adopted in lettuce production [16]. Form the review I have seen that The WP increased as the irrigation level reduced.

In this review, the effect of irrigation intervals on growth and yield of onion, maize yield, growth characteristics for Chile pepper, vegetative growth and yield, growth analysis of soybean, forage production, growth and development of tomato, the effect of irrigation level and irrigation frequency on the growth of mini Chinese cabbage and Influence of irrigation interval, nitrogen level and crop geometry on production lettuce have been reviewed. The best performance irrigation interval for onion, maize, pepper, okra, soybean, forage, tomato, cabbage and lettuce are 5, 6, 1, 12, 8, 20, 1, 4 and 2 day respectively. Crop type, crop growth stage soil type, climate condition (temperature, rainfall, humidity, sunshine hour and wend speed) duration of the environment should be properly addressed and potential evapotranspiration and reference evapotranspiration should be estimated for determining of irrigating interval. In these cases, some of the studies are properly addressed these important parameters but some of the study not indicates. On the other hand chemical composition of water and soil, fertilizer application, method of research design and plant geometry are should be identified to eradicate the misjudgment of your best productivity of irrigation interval.

Trickle irrigation is one and only of the water saving, progressive and advanced irrigation methods over gravity irrigation. In the point view of this, the research was lead to study the efficiency of Trickle irrigation over gravity irrigation in growth and yield of garlic in case Rabi & Kharif periods, wonka kebele, Ethiopia. The results indicated that trickle irrigation was well achieved greater over gravity irrigation method in terms of greater crop morphology, yield and quality of bulb. Trickle irrigation method documented maximum crop height (67.77 cm & 62.85), amount of leaves (10.25 & 8.00) and neck thickness (1.63 cm & 1.40 cm) in both Rabi and Kharif periods. The bulb equatorial and polar diameter, higher gross product in addition to marketable product achieved in trickle irrigation method. In trickle irrigation method, the gross product and marketable product improved by 12.54% and 22.63%, respectively in Rabi periods over gravity irrigation method and better water use productivity & as well saved 29.40% & 29.20% water for the period of Rabi & Kharif periods, respectively.