Negative pressure irrigation increases vegetable water productivity and nitrogen use efficiency by improving soil water and NO3–-N distributions

Abstract Negative pressure irrigation (NPI), which is a new subsurface technique, promotes vegetable yield, water productivity (WP), and nitrogen use efficiency (NUE). However, it not clear how NPI improves growth, especially in terms of supply characteristics uniformities soil nitrogen. In this study, cucumber pot experiment that had 0 kPa (PW1), –5 (PW2), –10 (PW3), –15kPa (PW4), traditional (PCK) treatments under application (N1) no (N0) was conducted to reveal the its effect on growth. There are two main characteristics: 1) automatically supplying based consumption water, 2) keeping content stable during growth period. addition, relationship between NO3–-N distribution throughout profile investigated by carrying out tomato field experiments. The one were with (F1W) furrow (F1CK). We also carried (F2W), (F2CK), drip (F2D) another experiment. results showed cumulative N1 higher than N0 PW1, PW2, PW3 Volumetric system more vegetative period irrigation. increased yields appropriate pressures (–10–0 kPa) compared PCK treatment experiments reduced fertilizer inputs method significant influence yield