Effects of different surface cover materials on stoichiometric characteristics and δ¹³C of leaves and fine roots of Prunus × hongmeixing

To reveal the response patterns of stoichiometry and carbon isotope (δ¹³C) in different organs of Prunus × hongmeixing to mulching materials and understand C-N-P allocation strategies between fine roots and leaves, four mulching treatments (white plastic mulch, black plastic mulch, sawdust mulch, and wheat straw mulch) were established with uncovered control. Nutrient traits (C, N, P) and δ¹³C content in leaves and fine roots were quantified. The results showed that: Sawdust mulch significantly reduced leaf C content, while wheat straw mulch significantly increased fine roots C content. All four mulch treatments significantly increased fine roots N content, with wheat straw mulch yielding the highest leaves and fine roots N content. Additionally, wheat straw mulch significantly decreased fine roots P content.. All four mulch treatments significantly increased δ¹³C in leaves and fine roots. Wheat straw mulch established allometric scaling relationships in C, N, and P concentrations between fine roots and leaves. It accelerated C and P allocation to leaves and N allocation to fine roots in P. × hongmeixing. Black plastic mulch enhanced C allocation to fine roots. All four ground cover treatments promoted greater N allocation to fine roots of P. × hongmeixing, while wheat straw mulch increased P allocation to leaves. Wheat straw mulch elevated phosphorus content in deep soil layers, enhanced nitrogen accumulation in fine roots and phosphorus allocation to leaves, while simultaneously increasing δ¹³C values across organs. Sawdust mulch and black plastic mulch moderately improved nutrient acquisition by fine roots, whereas white plastic mulch potentially reduced fine root nitrogen content. These results confirm that P. × hongmeixing differentially adjusts nutrient allocation strategies among organs under various mulch treatments to achieve acclimation to regional environments.