Root growth is one of the main strategies to improve phosphorus (P) uptake from soils, but both root growth and P movement to the roots are impaired by soil water shortage. Several studies have evaluated the effect of P availability on root growth, as well as the impact of root growth on drought tolerance, but there is still a lack of unity in this knowledge. Thus, the objective of this review article is to identify the primary P management strategies that can enhance root growth and P acquisition in crops during dry spells. This review synthesizes studies published from 1963 to 2025, with emphasis on field-based experiments conducted under rainfed or water-limited conditions. For this purpose, articles carried out in different parts of the world were reviewed. Based on these studies, we found that the main challenge to improving P acquisition by plants under water stress is to enhance P availability in the soil subsurface, which remains wetter for a longer period. Broadcast application of P has been a problem mainly in rainfed and water-restricted environments, and application of P in the sowing furrow is recommended in these environments. The use of cover crops, crop-livestock integration, crop rotation, liming, adjustment of optimum pH, and increase of C and humic substances in the soil are important techniques to improve the availability and mobility of P in the soil and consequently the root growth and P uptake in depth. Plants and cultivars with larger root systems and especially long and dense root hairs can improve drought tolerance and PUE. Growth-promoting microorganisms can help in drought tolerance through better hormonal balance and root growth, but there is still a need for new knowledge associated with P solubilization under field conditions. Future research should seek to evaluate the interactive effects of the use of microorganisms, root growth, and drought tolerance with field studies in different production systems.
Cordeiro et al. (Wed,) studied this question.