How changing root system architecture can help tackle a reduction in soil phosphate (<scp>P</scp>) levels for better plant <scp>P</scp> acquisition

Abstract

Abstract The readily available global rock phosphate ( P ) reserves may run out within the next 50–130 years, causing soils to have a reduced P concentration which will affect plant P uptake. Using a combination of mathematical modelling and experimental data, we investigated potential plant‐based options for optimizing crop P uptake in reduced soil P environments. By varying the P concentration within a well‐mixed agricultural soil, for high and low P (35.5–12.5 mg L −1 respectively using Olsen's P index), we investigated branching distributions within a wheat root system that maximize P uptake. Changing the root branching distribution from linear (evenly spaced branches) to strongly exponential (a greater number of branches at the top of the soil) improves P uptake by 142% for low‐ P soils when root mass is kept constant between simulations. This causes the roots to emerge earlier and mimics topsoil foraging. Manipulating root branching patterns, to maximize P uptake, is not enough on its own to overcome the drop in soil P from high to low P . Further mechanisms have to be considered to fully understand the impact of P reduction on plant development.