TY - JOUR
T1 - Distributions of rare earths and heavy metals in field-grown maize after application of rare earth-containing fertilizer
AU - Xu, Xingkai
AU - Zhu, Wangzhao
AU - Wang, Zijian
AU - Witkamp, Geert Jan
N1 - Funding Information:
This project was financially supported by the National Science Foundation of China (Grant No 29890280-2-3), by the Chinese Academy of Sciences (RCEES-KIP-9901) and by the Royal Netherlands Academy of Arts and Sciences (00CDP005). The Fengqiu Agro-Ecological Experimental Station of the Chinese Academy of Sciences (Grant No. 201605) and the K.C. Wong Education Foundation (Hong Kong) also financially aided this work.
PY - 2002/7/3
Y1 - 2002/7/3
N2 - Rare earths are widely applied in Chinese agriculture to improve crop nutrition through the use of fertilizers, yet little is known of their accumulation in field-grown crops. We have studied the distribution of 16 rare earths (Sc, Y and 14 lanthanide elements) in field-grown maize and the concentration of heavy metals in the grains after application of rare earth-containing fertilizer. When maize entered the vigorous vegetation growth stage (e.g. early stem-elongation stage), rare earth-containing fertilizer was applied to the soil with irrigation water. At 10 days after application of the rare earths, significantly dose-dependent accumulative effects of individual rare earth concentrations in the roots and the plant tops of maize were observed, with the exception of Sc and Lu. At the level of 2 kg rare earths ha-1, accumulative concentrations of most light rare earths (e.g. La, Ce, Pr and Nd) and Gd in the plant tops were much larger than those in the control. Concentrations of individual rare earths in a field-grown maize after application of rare earths decreased in the order of root≫leaf>stem>grain. During the maize growth period, selective accumulation of individual rare earths (e.g. La, Ce) in the roots seemed to be in dynamic equilibrium, and the distribution of these elements in the plant tops was variable. At a dosage of less than 10 kg rare earths ha-1, no apparent accumulative concentrations of individual rare earths appeared in the maize grains. Under the experimental conditions, application of rare earth-containing fertilizer did not induce an increase in the concentrations of heavy metals in the grains. We conclude that the present dosage of rare earths (<0.23 kg ha-1 year-1) currently applied in China can hardly affect the safety of maize grains in arable soil, even over a long period.
AB - Rare earths are widely applied in Chinese agriculture to improve crop nutrition through the use of fertilizers, yet little is known of their accumulation in field-grown crops. We have studied the distribution of 16 rare earths (Sc, Y and 14 lanthanide elements) in field-grown maize and the concentration of heavy metals in the grains after application of rare earth-containing fertilizer. When maize entered the vigorous vegetation growth stage (e.g. early stem-elongation stage), rare earth-containing fertilizer was applied to the soil with irrigation water. At 10 days after application of the rare earths, significantly dose-dependent accumulative effects of individual rare earth concentrations in the roots and the plant tops of maize were observed, with the exception of Sc and Lu. At the level of 2 kg rare earths ha-1, accumulative concentrations of most light rare earths (e.g. La, Ce, Pr and Nd) and Gd in the plant tops were much larger than those in the control. Concentrations of individual rare earths in a field-grown maize after application of rare earths decreased in the order of root≫leaf>stem>grain. During the maize growth period, selective accumulation of individual rare earths (e.g. La, Ce) in the roots seemed to be in dynamic equilibrium, and the distribution of these elements in the plant tops was variable. At a dosage of less than 10 kg rare earths ha-1, no apparent accumulative concentrations of individual rare earths appeared in the maize grains. Under the experimental conditions, application of rare earth-containing fertilizer did not induce an increase in the concentrations of heavy metals in the grains. We conclude that the present dosage of rare earths (<0.23 kg ha-1 year-1) currently applied in China can hardly affect the safety of maize grains in arable soil, even over a long period.
KW - Dose-dependent accumulation
KW - Heavy metals
KW - Maize
KW - Rare earth-containing fertilizer
KW - Rare earths
UR - http://www.scopus.com/inward/record.url?scp=0037014526&partnerID=8YFLogxK
U2 - 10.1016/S0048-9697(01)01150-0
DO - 10.1016/S0048-9697(01)01150-0
M3 - Article
C2 - 12109484
AN - SCOPUS:0037014526
SN - 0048-9697
VL - 293
SP - 97
EP - 105
JO - Science of The Total Environment
JF - Science of The Total Environment
IS - 1-3
ER -