Effect of irrigation systems and deficit irrigation levels on productivity and water use efficiency of tomato crop under Sana'a Basin conditions

Abstract

The Sana'a Basin is located between latitudes 16.8 - 17.4o north and longitudes 40-45o east. The basin's elevation above sea level is 2200 meters, the basin's climate is semi-arid with an average rainfall of 235 mm/year. The total area of ​​the Sana'a Basin is 320,000 hectares, the cultivated area is 107,000 hectares. In the Sana'a Basin, the annual water consumption for irrigated agriculture is 180 million m3 drawn through more than 6,000 wells, while the basin's rainfall deficit is 400%, which causes the groundwater level to drop by about 6 meters annually. Although the water requirements for irrigated crops are 70 million m3, this means that the efficiency of traditional irrigation used in the basin does not exceed 40%. This scientific research aims to increase productivity and water use efficiency under the conditions of the Sana'a Basin. The research studied the effect of different irrigation systems (Drip-in, Drip-on, lines + Hydrosol soil conditioner, and lines), and water supply levels (50, 75, and 100% deficit irrigation level relative to actual need) on productivity, water consumption, and water use efficiency of tomato crop under the conditions of Sana'a Basin, Yemen. The research was carried out at the Educational Farm - Faculty of Agriculture - Sana'a University. The experiment was designed according to the split-plot design. Statistical analysis of the data and formulation of prediction equations for the traits were carried out using a computer program (SAS). The results of the research show, for example - but not limited to: that the effect of different irrigation systems had a significant effect at the 0.01 level on productivity, water consumption, and water use efficiency of tomato crop, where the surface irrigation + polymer system achieved the highest productivity of tomato crop 31443.3 kg/ha, while surface irrigation gave the lowest productivity 24113.3 kg/ha. While the drip-in irrigation system recorded the lowest water consumption of 397.16 mm, while the surface irrigation system gave the highest water consumption of 595.75 mm. While the drip-on irrigation system recorded the highest water use efficiency of 6.52 kg/m3 water, while the surface irrigation system gave the lowest efficiency of 4.22 kg/m3 water. The results also showed that the effect of different water supply levels (deficit irrigation levels) had a significant effect at the 0.01 level on productivity, water consumption, and water use efficiency of tomato crop, where the 100% water supply level recorded the highest tomato crop productivity of 30644.2 kg/ha, while the 50% level gave the lowest productivity of 21724.2 kg/ha. While the 50% water supply level recorded the lowest water consumption of 330.98 mm, while the 100% water supply level gave the highest water consumption of 661.94 mm. While the 50% water supply level recorded the highest water use efficiency of 6.77 kg/m3 water, the 100% water supply level gave the lowest water use efficiency of 4.76 kg/m3 water. The results also showed that the interaction effect between irrigation systems and water supply levels had a significant effect at the 0.01 level on water consumption, while productivity and water use efficiency were not significantly affected, as the drip-in system at the 50% water supply level recorded the lowest water consumption of 264.78 mm, while the line irrigation system at the 100% water supply level gave the highest water consumption of 795 mm. While the line + polymer irrigation system at the 100% water supply level recorded the highest tomato crop productivity of 37667 kg/ha, while the line irrigation system at the 50% water supply level gave the lowest productivity of 19887 kg/ha. While the drip-on irrigation system at 50% water supply level recorded the highest water use efficiency of 7.78 kg/m3 water, the line irrigation system at 100% water supply level gave the lowest water use efficiency of 3.47 kg/m3 water.