Biochar amendments and drought tolerance of plants

Drought stress is a potential threat that impacts growth, development, and productivity worldwide. Additionally, the severe changes in climate conditions intensified the magnitude of drought stress, negatively affecting food security. Various methods have been applied to mitigate the negative impacts of drought stress on plants. Among these applicants, biochar has been recommended as an economically friendly approach that affects soil properties and plant health under stress conditions. It has been documented that biochar influences the soil water-holding capacity, total pore space, and water retention, which are key factors in modulating the soil organic matter, soil structure, soil aggregate stability, nutrient availability, soil water retention, and availability under drought stress. In addition, biochar exerts beneficial effects on soil microorganisms, which further help the plants to tolerate stressful conditions. Under the interactive effect of biochar, the plants improve their weight and yield due to upregulation of water uptake, nutrient homeostasis, photosynthetic activity, chlorophyll synthesis, osmolytes, hormonal balance, membrane stability, and reduction of oxidative stress by improving the antioxidant system. Thus this chapter will discuss a description of the effect of drought on plants, the history and production of biochar, the role of biochar on soils under drought stress, the role of biochar in plants experiencing different water regimes, and then the co-application of biochar and other additives (microorganisms or chemical agents) on drought-stressed plants.