Root Morphological Adjustments of Crops to Improve Nutrient Use Efficiency in Limited Environments

ABSTRACT

A large portion of applied phosphorus fertilizer undergoes adsorption/fixation due to high pH and calcareous content of soils and becomes unavailable for plant uptake. Plants undergo many morphological and physiological adaptations to overcome the low phosphorus availability. Many plants modify their root morphology and biomass in low phosphorus environments by exploring a greater more soil volume. This study measured plant root morphological and biomass adaptation at different levels of applied phosphorus and its effect on phosphorus use efficiency. Results showed that phosphorus use efficiency, root volume, number of root tips, root surface area, root length, and root length were higher at a low levels of phosphorus with average root diameter and root phosphorus were reduced at lower levels of applied phosphorus. Maize performed better in case of root adaptation; however, phosphorus use efficiency was higher for wheat. Both plant species responded to low phosphorus application by enhancing their root morphology and root production with an increase in phosphorus use efficiency. A significant correlation (r² ≥ 60%) was observed between root morphology and phosphorus use efficiency. Plants that explore more soil volume by modifying root morphology were found to have low critical phosphorus requirements by efficiently utilizing phosphorus and amount of phosphorus fertilizer application is reduced.

KEYWORDS:

• Calcareous soils
• phosphorus fixation
• root morphology
• root biomass adaptations
• phosphorus use efficiency

Acknowledgments

This study was funded by the Higher Education Commission, Pakistan under the PhD fellowship award and supported by Saline Agriculture Research Center, ISES, UAF, Pakistan.