Influences of subsurface drip irrigation and surface drip irrigation on bell pepper growth under different fertilization conditions

A 2-year field experiment was conducted in 2007, 2008 to study the response of bell pepper to subsurface drip irrigation (SDI) and surface drip irrigation (DI). Four nitrogen levels of 0, 75, 150, 300 kg/hm-2 (N0, N75, N150, N300) comprised the fertigation treatments. The irrigation interval was 4 days. The results showed that, bell pepper yields for treatment SDI were higher than that for DI by 4% in 2007, and 13% in 2008, respectively. The water consumption of SDI was lower than that of DI by 6.7% in 2007, and 7.3% in 2008, respectively. The root length density of SDI and DI was 1.46 and 2.44 times BI (border irrigation). The percent of root length under 10 cm of SDI were higher than that of DI by 7 percent, which means SDI not only promote the growth of crop root system, but also promote deep insertion of the root system. Treatment SDI N150 was recommended as the optimal strategy for improving bell pepper yield and WUE, reducing NO3--N leaching.