Changes in nutrient resorption efficiency with nitrogen and zinc addition and mowing in a meadow steppe

Understanding how interacting environmental drivers alter plant nutrient resorption is essential for elucidating nutrient cycling in grasslands. We conducted a nine-year field experiment in a meadow steppe to examine the effects of nitrogen (N, 10 g N m⁻2 yr⁻1) and zinc (Zn, 0.5 g Zn m⁻2 yr⁻1) additions and mowing on community-level nutrient resorption efficiency (RE). We quantified RE for ten macro- and micronutrients and explored their links with soil properties, species richness, and aboveground productivity. N addition enhanced RE for N (+12.9%), P (+15.4%), S (+159.1%), and Mg (+64.4%), supporting the growth optimization hypothesis. Mowing reduced RE for N (–14.0%) and P (–4.8%) but increased RE for Mg (+26.0%) and Fe (+60.4%), indicating compensatory strategies. Zn addition showed limited effects on macronutrient RE but markedly altered micronutrient dynamics, weakening ZnRE through negative feedback and modifying Fe resorption depending on context: reducing by 113.8% in CK and 61.4% under N addition but enhancing by 24.3% under mowing treatment and 51.3% in treatment of combined mowing and N addition. Aboveground productivity was the strongest predictor of RE, surpassing soil nutrient availability. Our findings reveal that additions of N and Zn and mowing jointly regulate element-specific nutrient resorption and plant functional adjustments, reshaping nutrient cycling and productivity patterns in temperate grasslands.