Irrigation and biochar effects on pearl millet and kinetics of ammonia volatilization from saline sandy soils

Abstract

Little information is available about biochar’s role in kinetics of ammonia (NH3) volatilization and growth of pearl millet (Pennisetum glacum L.) cultivated on a saline sandy soil under different levels of soil moisture. A field experiment was carried out for two years to explore biochar impacts in reducing the hazards of salts and NH3 volatilization from saline sandy soils. Biochar was added in three doses (0, 5 (BC5), and 10 (BC10) ton ha−1) and the soil was irrigated to 100% (I100), 80% (I80), and 60% (I60) of plant-available soil water. The experiment was factorial (3 × 3) and was laid out in a split plot design. results: Biochar enhanced the soil quality, availability and concentrations of nutrients in plant, and chlorophyll synthesis, on the other hand it reduced Na, Cl, and proline in the leaf tissue. Increasing the soil moisture from I60 to I100 elevated nutrients availability in soil and concentrations of nutrients in plant and caused remarkable increases in the quality of forage material. I100 enhanced the forage yield by 21.2 and 36.6%, respectively, in the first and second year compared with I60. BC5 and BC10 enhanced the forage yield by 18.4 and 31.8% and caused 19.1 and 34.7% increases in the water use efficiency (overall the irrigation treatments). Increasing the soil moisture and the application of biochar reduced NH3-volatilization. Biochar and soil moisture status affected significantly on the kinetics of NH3 loss and the half-life time. I100 increased the half-life time by 78.7% in comparison with I60. Addition of BC5 and BC10 to the soil elevated the half-life time by 13.5 and 35.8% compared to the control. BC10 and I100 reduced the NH3 volatilization and enhanced the forage yield of pearl millet. Controlling soil moisture and adding biochar are important strategies to minimize the negative impacts of salinity and reduce the emission of NH3 in addition to improving the performance of saline sandy soils.