New strategies to overcome water limitation in cultivated maize: Results from sub-surface irrigation and silicon fertilization.

The increasing growth of the world's population has established an unprecedented pressure in the availability of fresh water resources, with food production systems consuming over 70% of the world's fresh water withdrawals. Other pressures include climate change effects and the increasing number of semi-arid regions. The present challenges are therefore the maintenance of high production rates with fewer resources, especially in regions where water is becoming less accessible. In this study, we have tested the effect of sub-surface irrigation and silicon fertilization in maize growth with and without water limitation. These solutions have been suggested as effective in drought conditions but an overall study of their effects on the soil water balance and root length density is lacking. We have conducted a pot experiment with maize for 101 days where measurements in soil water content and root length were taken. Also, Hydrus 2-D was used to simulate the root water uptake and calculate the water balance. Results show that both sub-surface irrigation and silicon fertilization increase the root system by 21% and 34% respectively in water stress situation. Also, in the case of no water stress, silicon fertilization still induces an increase of 11% in the root development, showing that this solution has positive effects even when the crop is not hydrologically limited. Indeed the root water uptake was higher for the silicon treatment when no water limitation was present (71.6 L), compared to the sub-surface irrigation (62.5 L) and the control (62.3 L). While sub-surface irrigation generally decreased evaporation, the silicon treatment lowered drainage by promoting a better and more efficient root water uptake.