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

Nutrient resorption can affect plant growth, litter decomposition, and nutrient cycling. Although the effects of nitrogen (N) and biochar fertilizers on soil nutrient concentrations and plant nutrient uptake have been studied, an understanding of how combined applications of N and biochar affect plant nutrient resorption in plantations is lacking. In this study, we applied N (0, 30, 60, and 90 kg N ha−1 yr−1 defined as N0, N30, N60, and N90, respectively) and biochar (0, 20, and 40 t biochar ha−1 defined as BC0, BC20, and BC40, respectively) to the soil of a Moso bamboo plantation. We investigated the effects of these treatments on N and phosphorus (P) resorption by young and mature bamboo plants, as well as the relationships between nutrient resorption and leaf and soil nutrient concentrations. Young bamboo showed significantly greater foliar N resorption efficiency (NRE) and P resorption efficiency (PRE) than mature bamboo. N addition alone significantly increased the N resorption proficiency (NRP) and P resorption proficiency (PRP) but significantly decreased the NRE and PRE of both young and mature bamboo. In both the N-free 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 negatively correlated with fresh leaf N and P concentrations and soil total P concentration but significantly positively correlated with soil pH. 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 effect of N addition on nutrient resorption in young bamboo but reduced the negative effect on that of mature bamboo under N-addition treatments. This study provides new insights into the combined effects of N and biochar on the nutrient resorption of Moso bamboo and may assist in improving fertilization strategies in Moso bamboo plantations.

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

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.

Biomass allocation between leaf and stem regulates community-level plant nutrient resorption efficiency response to nitrogen and phosphorus additions in a temperate wetland of Northeast China

Aims Nutrient resorption is a crucial component of plant nutrient use strategy, yet the controls on the responses of community-level nutrient resorption to altered nutrient availability remain unclear. Here, we addressed two questions: Did leaf and stem nutrient resorption respond consistently to increased nutrient availability? Was community-level plant nutrient resorption response after nutrient enrichment driven by the intra-specific plasticity in plant nutrient resorption or by altered species composition? Methods We investigated the changes in aboveground biomass, and leaf and stem nutrient resorption of individual species after three-year nitrogen (N) and phosphorus (P) additions, and assessed community-level nutrient resorption response to three-year nutrient additions in a graminoid-dominated temperate wetland, Northeast China. Important findings For both leaves and stems, N and P additions did not affect nutrient resorption efficiency, but they decreased respective nutrient resorption proficiency. Similarly, community-level N and P resorption proficiency declined with respective nutrient addition. Community-level N and P resorption efficiency was reduced by N addition primarily due to altered community composition and declined leaf:stem ratio. These results suggest that leaf and stem nutrient resorption processes exhibit consistent responses to increasing nutrient availability in the temperate wetland. These findings highlight the importance of altered species composition and biomass allocation between leaf and stem in driving community-level nutrient resorption response to nutrient enrichment.

Nutrient Dynamics and Decomposition of Riparian Arundinaria gigantea (Walt.) Muhl. Leaves in Southern Illinois

<p class="1Body">Leaf litter quality and quantity can influence soil nutrient dynamics and stream productivity through decomposition and serving as allochthonous stream inputs. Leaf deposition, nitrogen (N)-resorption efficiency and proficiency, and decomposition rates were analyzed in riparian stands of <em>Arundinaria gigantea </em>(Walt.) Muhl.<em> </em>in southern Illinois for the first time to determine potential nutrient cycling from riparian canebrake restoration. Leaf litter was collected from five established canebrakes monthly over one year and a decomposition study was conducted over 72 weeks. Live leaves, freshly senesced leaves, and decomposed leaves were analyzed for carbon (C) and N content. Leaf litterfall biomass peaked in November at twice the monthly average for all but one site, indicating a resemblance to deciduous leaf fall patterns. Nitrogen and C concentrations decreased 48% and 30%, respectively, between live leaves and 72 weeks following decomposition. High soil moisture appeared to slow decomposition rates, perhaps due to the creation of anaerobic conditions. Cane leaves have low resorption proficiency and nutrient-use proficiency, suggesting that these riparian canebrakes are not N limited. Giant cane should be considered in multispecies riparian buffer creation since it has this potential to supply carbon and nitrogen to the soil and to macroinvertebrates in the streams for a longer period of time and year round.</p>