Phosphorus Application Decreased Copper Concentration but Not Iron in Maize Grain
Wei Zhang,
Chunqin Zou,
Xiuxiu Chen,
Yumin Liu,
Dunyi Liu,
Huaiyu Yang,
Yan Deng,
Xinping Chen
Affiliations
Wei Zhang
College of Resources and Environment, Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
Chunqin Zou
College of Resources and Environment, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China
Xiuxiu Chen
College of Resources and Environment, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China
Yumin Liu
College of Resources and Environment, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China
Dunyi Liu
College of Resources and Environment, Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
Huaiyu Yang
College of Resources and Environment, Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
Yan Deng
College of Resources and Environment, Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
Xinping Chen
College of Resources and Environment, Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
Copper (Cu) and iron (Fe) are essential micronutrients for plants and animals. How phosphorus (P) application affects Cu and Fe concentrations in maize grain still remains unclear. Two-year field studies were conducted in a long-term experiment with six P levels (0, 12.5, 25, 50, 100, and 200 kg∙ha−1 P) on calcareous soil. Phosphorus application significantly decreased the average grain Cu concentration by 12.6% compared to no P treatment, but had no effect on grain Fe concentration. The copper content increased as the P application rate increased from 0 to 25 or 50 kg·ha−1, but then decreased, while Fe content kept increasing. As the P application rate increased, the specific Cu uptake by the roots decreased, but not for Fe. The root length density in response to P application had a positive relationship with shoot Cu and Fe content. The shoot Cu content and grain Cu concentration decreased with the reduction in the arbuscular mycorrhizal fungi (AMF) colonization of roots due to increasing P application. The reduction in grain Cu concentration with increasing P rates could be partly explained by the decreasing uptake efficiency.