Deep and continuous root development in ameliorated soil improves water and nutrient uptakes and wheat yield in water-limited conditions

Despite the widespread co-occurrence of subsoil acidity and compaction, the interaction between these factors and their combined effects on root system development under water-limited conditions is poorly understood. This study aimed to investigate how the removal of soil strength and acidity influenced root development and examine relationships between root system properties and shoot growth under field conditions. Images of root growth were obtained in situ by using rhizotron facilities to assess the temporal effects of soil improvement through loosening and lime incorporation on wheat root development in the 2018 season. Following this, we examined the relationship between enhanced root systems, water and nutrient uptakes, and overall crop performance. The results indicated that improved soil conditions significantly enhanced planar root length density (pRLD) through the elongation and proliferation of wheat roots in the subsoil. Regressing tree analysis suggested that subsoil strength had a more dominant influence on pRLD compared to soil pH or aluminium — leading to higher water uptake, wheat head density and yield. In addition to the benefit of loosening, the lime treatment improved soil acidity, promoting continuous root growth with root hairs, allowing plants to access previously unavailable nutrients and improve yield further. This highlights the critical role of managing multiple soil constraints for optimising crop productivity. In this study, the integration of root images and soil properties data provided a deeper understanding of root-soil interactions which could be useful for developing sustainable soil management practices to optimise crop productivity under challenging conditions.