**6. Potential role of biostimulants against drought**

Drought stress impacts the agriculture sector and can adversely affect the plant's morphological, physiological, biochemical, and molecular changes, leading to reduced plant growth and productivity [68]. Water stress also results in increased reactive oxygen species (ROS) accumulation in the plant, which disturbs different cellular mechanisms, including enzyme inhabitation, protein reductase, DNA, RNA, and membrane lipid peroxidation damage leading to cell death [69]. It also disturbed the stomatal closure, enzyme activity, photosynthesis process, and transpiration rates [70].

*Biostimulants Application: An Innovative Approach to Food Security under Drought Stress DOI: http://dx.doi.org/10.5772/intechopen.107055*

Biostimulants can boost crop toleration against drought stress and improve crop productivity [9]. Moreover, it can potentially increase the growth and yield of plants in farming by developing tolerance against drought stresses, enhancing water retention capability, root strengthening and development, and improving nutrient and water use efficiency [71]. The impact of biostimulants highly depends on time and rate of application, abiotic environmental factors, and crop variety [72]. Studies reported that using pollen grain extract as biostimulant improved the growth and essential oil productivity of *Ocimum basilicum* under drought stress conditions [73].

In addition, arbuscular mycorrhizal fungi, plant-growth-promoting rhizobacteria, and local green compost improve date palm productivity under a water stress environment [74]. *Ascophyllum nodosum* extract biostimulants also developed drought tolerance in tomato plants [11]. Under mild drought stress, the application of *A. nodosum* seaweed extract (SWE) enhanced spinach growth [75]. While foliar-applied (SWE) improved bean yield cultivars under irrigation regimes by changing fatty acid and biochemical profiles [76]. Further benefits of biostimulants and plant responses under different conditions are given in **Table 1**.

### **7. Future aspects and challenges**

To make water available for human consumption and irrigation, an adequate water management system must be adopted worldwide for sustainable agriculture and profitable activity of water, especially in arid and semiarid regions [83]. Biostimulants have been reported to address drought stress while maintaining crop yield and productivity [9]. However, the response of different crop cultivars and the long-term impacts of biostimulants need to be studied. Moreover, multiple sources of biostimulants should be adopted after identifying their synergistic effects rather than relying on a single basis. Literature reported the research conducted at tunnel farms, experimental greenhouse areas, and hydroponic conditions. However, field experiments should be performed to find the potential of biostimulants in real-life situations. In addition, the use of biostimulants can also provide environmental benefits. It can be used to tackle food demand by improving productivity under environment stress as well as utilization of waste products to prepare biostimulants for environment sustainability.

Furthermore, the effectiveness of biostimulants in normal environmental conditions and their comparison with chemical fertilizers can also give new insights. The use of biostimulants for sustainable agriculture to reduce agrochemical products (such as chemical fertilizers and pesticides) can be studied. Moreover, the high demand for biofertilizers and biopesticides can be addressed using natural biostimulants, including seaweed, pollen grain, moringa leaf, and many other extracts. Therefore, new and economical biostimulants with different compositions should be introduced into the market along with their specifications to specific crop/cultivar, application method, time, and dose, and their effectiveness toward specific stress conditions should be mentioned. Biostimulants vary in nature depending upon their composition and the material from which they are derived. Due to the uniqueness of every type of biostimulant, the mechanism behind its activity and performance is still not identified; thus, further studies are required in this regard because it can help scientists identify more benefits of biostimulants.


#### **Table 1.**

*Benefits of biostimulants and plant responses.*

### **8. Conclusion**

High food demand, climate change, increasing incidences of weather extremities, and other biotic and abiotic stresses have created severe pressure on crops. Conventional agriculture practices are challenging to maintain in such scenarios.

*Biostimulants Application: An Innovative Approach to Food Security under Drought Stress DOI: http://dx.doi.org/10.5772/intechopen.107055*

Therefore, farmers and scientists are facing the challenge of finding an appropriate approach to tackle environmental stresses and maintain crop productivity. Biostimulants are an innovative tool to address the issue without adversely affecting crop quality and yield loss. We studied the latest research in this aspect, and biostimulants have reported positive responses against adverse environmental conditions. However, further studies are required to identify the crop response in different areas of the globe and its long-term potential under other stress conditions.
