Soil improvement and tomato production affected by tillage and drip irrigation with saline water in heavy coastal saline soil

Abstract Establishing rational method for irrigation with saline water is the key to improve the agroecological environment in heavy coastal saline soil. A two-year field experiment was conducted in Bohai Rim region, China. Three tillage modes [undisturbed soil without planting (UP), ridge tillage without irrigation (TW) and with drip irrigation (T)] were designed to investigate the effect of tillage on salt leaching. Five treatments of irrigation water salinity [ECw of 0.7 (T1), 3.2 (T2), 4.7 (T3), 6.2 (T4) and 7.8 (T5) dS/m] were designed under T mode to investigate the effects of ECw on salinity (ECe) and alkalinity (SAR and pHe) of soil and tomato production and irrigation water use efficiency (IWUE). Results showed the soil desalination rate (SDR) of T mode was the highest than the TW and UP modes. The linear relationships between ECw and SDR, irrigation amount and SDR were observed. The final mean ECe and SAR for T1 to T5 dropped by 58.5–65.3% and 33.7–42.3%, respectively. The final mean soil pHe for T1-T5 treatments from 7.82 dropped to 7.75, 7.38, 7.44, 7.36 and 7.16, respectively. The survival rate decreased with the increment of ECw, and exceeded 90% when ECw below 7.8 dS/m. As ECw below 4.7 dS/m, growth and yield of tomato and IWUE were not inhibited. The relationships between ECw and survival rate, relative yield, relative IWUE and qualities were quantified, respectively. Using ECw below 3.9 dS/m under T mode was the recommended to successful cultivating and high-quality production of tomato in heavy coastal saline soil.