Biochar Amendment Alters The Nutrient-Use Strategy of Moso Bamboo Under N Additions

Abstract Background: While we know that N and biochar fertilizers affect soil nutrient concentrations and plant nutrient uptake, our understanding of how combined applications of N and biochar affect plant nutrient resorption in plantations is largely inadequate. A field experiment was conducted to investigate the effects of N (0, 30, 60, and 90 kg N ha-1 yr-1 or N0, N30, N60, and N90), in combination with biochar (0, 20, and 40 t biochar ha-1 or BC0, BC20, and BC40) on N and P resorption by young and mature bamboo plants as well as the relationship between nutrient resorption and leaf nutrient and soil concentrations. Fresh and senescent leaf samples were collected in July 2016 and March 2017, respectively.Results: Young bamboo showed significantly greater foliar N resorption efficiency (NRE) and P resorption efficiency (PRE) than mature bamboo. N additions alone significantly increased the N resorption proficiency (NRP) and P resorption proficiency (PRP) but decreased the NRE and PRE of both young and mature bamboo. In both the N-free (control) and N addition treatments, biochar amendments significantly reduced the foliar NRE and PRE of young bamboo but had the opposite effect on mature bamboo. Foliar NRE and PRE were significantly correlated with fresh leaf N and P concentrations and soil total P concentration. Conclusion: Our findings suggest that N addition inhibits plant nutrient resorption and alters the nutrient-use strategy of young and mature bamboo from “conservative consumption” to “resource spending.” Furthermore, biochar amendment enhanced the negative priming effect of N addition on nutrient resorption of young bamboo but reduced the negative effect on that of mature bamboo. This study provides new insights into the combined effects of N and biochar additions on the nutrient resorption of Moso bamboo and may assist in improving fertilization strategies in Moso bamboo plantations.