Document Type : Research Paper
Authors
1
Agricultural Engineering Research Department, Fars Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Shiraz, Iran.
2
Fig Research Station, Fars Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Estahban, Iran.
Abstract
Estahban region in Fars province is mostly covered with rainfed fig trees. Gardeners have applied over-irrigation because of drought in recent years. In this study, irrigations were scheduled based on different crop water stress indexes by measuring canopy temperature. The treatments included irrigation at different Crop Water Stress Indexs (CWSI) of 0, 0.2, 0.4, 0.6, 0.8. A rain-fed treatment was also added as control. The trees were irrigated by hand using water tankers. During the two years of the research, the number of irrigations, yield, and water productivity were measured. Duncan test was used for statistical analysis of the treatments in a complete block test design with four replicates. Economical analyses were also done based on benefits and costs in 2017 and 2018. Results showed that the maximum observed CWSI was not more than 0.6. Irrigation increased the yield values from 3.1 kg/tree in rain-fed condition to 9.8 kg/tree in the fully irrigated treatment. However, water productivity decreased from a large value in the rainfed treatment to 0.65 kg/m3 in the fully irrigated treatment. The treatment that was irrigated once had amuch increase in yield and increase about 740000 and 1190000 Rials in net benefit compared to rain-fed treatment in the studied years. The net benefit of one irrigation in the two studied years was about 530000 and 990000 Rials/m3of applied water. These values decreased with increase in the irrigation times. The benefit cost ratio in the two studied years was 1.10 and 1.46 for rain-fed trees while it was 2.21 and 2.89 for single irrigation treatment, respectively. Therefore, by one supplemental irrigation of the rain-fed fig trees,the drought damages could be controlled, a significant economical benefit could be gained, and over-irrigation is avoided.
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