Impacts of Biochar on Hydro-Physical Properties of Sandy Soil under Different Irrigation Regimes for Enhanced Tomato Growth

The performance of biochar application in water conservation, salt distribution, water infiltration, and tomato growth was evaluated under regulated deficit irrigation (RDI) (40%, 60% and 80% of ETc) and partial root drying (PRD) systems by using different quality irrigation water. Date palm derived biochar was applied to sandy soil at 4% (w/w) in pots, and tomato was grown as the test crop under greenhouse conditions. The results indicated that soil moisture was decreased by 27.38% to 24.95% without biochar application at different levels of irrigation, whereas it increased by 8.11% and 5.48% with biochar application, compared with control treatment of 100% of ETc. Soil moisture was decreased by 12.78%, 15.82% and 12.78% for the 1st stage, 2nd stage and 3rd growth stage, respectively, while it increased by 37.93% at the 4th growth stage compared with full irrigation. Soil salinity ranged between 0.5 and 1.4 dS·m−1 with biochar application, while 0.7–2.1 dS·m−1. Cumulative infiltration at one minute varied between 1.89 and 2.79 cm and 1.74 and 2.79 cm for biochar and non-biochar treatments, respectively. Infiltration rate varied from 0.98 to 2.63 cm min−1 and 1.48 to 1.68 cm·min−1 for fresh and saline water, respectively. Overall, the results revealed that biochar application substantially improved the characteristics of sandy soil, subsequently resulting in water conservation.