Enhancing crop P uptake and reducing fertilizer P loss by Si-P co-fertilization?

Abstract Background and Aims The competition of silicate and phosphate for sorption sites results in Si additions releasing P into the soil solution, increasing P availability for crops. Another potential effect of Si in promoting P uptake is the stimulation of root growth. Although there has been evidence of these effects since the early twentieth century, they are currently not utilized in agricultural production. In this review, we compile the current knowledge on Si-P interactions in soil and discuss how they can be utilized to increase the P fertilizer use efficiency (PUE). Methods We conducted a thorough literature review and quantified the effect of Si fertilization on P uptake and PUE in a meta-analysis of 15 studies reporting on experiments with concomitant Si-P fertilization. Ten further studies were evaluated qualitatively. Results The application of Si resulted in an overall relative increase in plant P uptake of 52%. Most of the subsets (Si fertilizer forms, cultivated crop, pot/field study) showed Si-induced increased P uptake in the range of 26–53%, with notable outliers being paddy rice (74%) and field studies (67%). Conclusion We conclude that the joint application of Si-P has the potential to increase the fertilizer P use efficiency. Si-P co-fertilization could not only increase the phosphorus uptake of crops and thus the PUE, contributing to resource-efficient agricultural production and reduced environmental impact of phosphorus fertilization, but also crop stress tolerance. Generally, the role of soil Si in soil fertility, soil quality and soil health should be given more attention.