Abstract
A field study was conducted in 2016-2017 and 2017-2018 to evaluate the effects of air injection into an irrigation stream during the subsurface drip irrigation (SDI) process on the nutritional values and productivity of potato grown in clay loam soil. Two irrigation treatments (non-aerated and aerated) and six fertilizer applications (chicken, cow, rabbit, compost, mineral, and chicken + biochar) were compared. In the first growing season, the maximum yield occurred under aerated treatment with cow fertilizer (36.25 ton ha(-1)), while the minimum yield occurred under non-aerated treatment with chicken fertilizer (24.00 ton ha(-1)). On the other hand, the maximum and minimum yields in the second growing season were 35.00 and 24.74 ton ha(-1) under aerated and non-aerated treatments with cow fertilizer, respectively. Maximum water productivity was achieved under aerated treatment with cow fertilizer (10.04 and 9.13 kg m(-3) for the first and second growing seasons, respectively), while minimum water productivity was achieved under the non-aerated treatment with chicken + biochar fertilizer (5.91 and 5.26 kg m(-3) for the first and second growing seasons, respectively). Fertilization using aerated treatment yielded the best results and the highest coupling after air injection, compared with the traditional methods of adding soil fertilizer without aeration. The plant growth parameters significantly increased following aeration relative to non-aerated treatments for all fertilizer applications in both growing seasons. Air injection into the soil for potatoes, unsurprisingly, not only benefitted the crop by increasing the soil-air exchange rate but also promoted water infiltration rates and nutrient absorption and reduced drainage water, thus increasing water productivity and reducing the overall irrigation requirements.