Phosphorus Uptake and Translocation in Field-Grown Maize after Application of Rare Earth-Containing Fertilizer

ABSTRACT

In recent decades, rare earths and rare-earth containing fertilizers along with nitrogen (N) and phosphorus (P) fertilizers have been used by agriculturists to improve crop yield and quality. The interaction between rare earths and N has been explained in soils, yet little is known of the effect of rare earths on P nutrition of field-grown crops. When maize plants entered the early stem-elongation stage, a rare earth-containing fertilizer (lanthanum (La) and cerium (Ce) as major rare earths) was applied to the soil with irrigation water. Ten days after application of rare earths, there was no significant dose-dependent accumulation of P in the roots and shoots, with one exception where P concentrations increased in the roots at a dosage of 100 kg rare earths ha^{− 1}. However, at maturity, the application of rare earths at less than 10 kg ha^{− 1} significantly improved P uptake by field-grown maize and P transport to the grain. The application of rare earths at less than 10 kg ha^{− 1} increased crop yield. Other studies have shown that at rates less than 10 kg rare earths ha^{− 1}, there was no accumulation of heavy metals and rare earths in the grain, and that the present mean application rate of rare earths (< 0.23 kg ha^{− 1} year^{− 1}) currently applied in China was unlikely to affect the safety of grains in arable soils. Together, these field studies can give a scientific understanding of benefits and risks when utilizing rare earths in agriculture, and of the interaction between rare earths and P nutrition in field-grown crops.

Keywords::

• dose-effect
• maize
• P uptake
• rare earths
• safe assessment
• yield

ACKNOWLEDGMENTS

This project was financially supported by the Hundred Talents Project from the Chinese Academy of Sciences and by the National Natural Science Foundation of China. Special thanks are owed to Ms. Liu Yan, Ms. Ma Mei and Mr. Rao Kaifeng for chemical analysis and field experiments.

Notes

^a Total-LREs, total concentration of light rare earths (from La to Eu); Total-HREs, total concentration of heavy rare earths (from Gd to Lu);