Abstract
Sustainable food production in arid areas is limited by scarcity of good quality water for irrigation. Poor quality water, including saline water, is therefore increasingly being used for irrigation in these areas, with its adverse effect on crop growth and soil properties. For establishment of sustainable arid land agriculture with saline water, we evaluated two methods of subsurface irrigation using porous rubber pipes from which water seeps out under hydraulic pressure. In one method, two pipes at 20cm interval were laid at 5cm depth (1D), while in the other method, one pipe was laid at 5cm depth and the other pipe at 20 cm depth (2D). The experiment was conducted on dune sand with soybean using saline water (3000ppm Na Cl). Growth and water use efficiency of soybean and salt distribution and balance in the soil were studied. Plant growth and water use efficiency of soybean were higher with 2D than with 1D at the end of the experiment Salt was accumulated at soil surface regardless of the treatment, however, the salt amounts did not increase below the 5cm depth between the irrigation pipes in 2D treatment Therefore, when irrigation water is saline, 2D is better than 1D for soybean growth and efficient water use in later growth season. Results suggest that the 2D could be better to control the soil salinity condition.