مطالعات لايسيمتري روش هاي مديريت سطح ايستايي براي آبياري گوجه فرنگي

A Lysimetry Study of Water Table Management Methods in Tomato irrigation

In humid regions, water table control during growing season is a common irrigation method for efficient use of water and optimum crop production. However application of this method in arid and semi arid region is doubtful because of high evaporation rate and salt movement toward the root zone limitations. This research was conducted to examine the possibility of using water table control techniques (i.e., controlled drainage and sub irrigation) in an arid region (e.g., Iran) with special attention to its salinity management. Three water table control treatments including: free drainage (FD), controlled drainage (CD), and sub irrigation (SI) were considered. Treatments were applied in 12 tycimeters (90 cm height, 57 cm diameter). The experimental setup included three treatments and four replications. Water table was set at depth 55 cm from soil surface. The electrical conductivity (EC) of water was 1.5 dS/m. The crop cultivated in lycimeters was tomato. The soil leaching considered to be conducted when EC reached to the plant threshold level (EC = 3 dS/m). The results indicated that SI and CD methods can be used in arid and semi arid conditions. In all the treatments the soil EC was not reach to the crop threshold level. However the EC of soil surface layer in SI treatment was high, but it had not any significant effect on crop yield. The evidence was the higher yield of SI treatment than FD treatment. The total yield of CD was 73% more than FD and 12% more than SI. However the number of tomato fruits in CI) treatment was more than the other two treatments (FE), SI). Water consumption in SI was half of CD and FL) treatments, and consequently its water productivity (1.4 Kg/mʹ) was higher than the water productivity for FD (0.57 Kg/mi), and CI) (0.97 Kg/m3).