Abstract: [Objective]The objective of this study was to provide theoretical basis for reasonable management of Populus×euramericana ‘Neva’ plantations under different continuous cropping conditions. [Method]An Populus×euramericana ‘Neva’ plantation along Dawen River area was studied. The contents of major nutrient elements in leaves were measured. The variations of stoichiometric ratios and nutrient recovery under different continuous cropping conditions were analyzed. [Result]P and K contents in mature leaves of third generation plantation were significantly lower than those of first and second generations (P<0.05), while the content differences were not significant between the first and second generations (P>0.05), respectively. The effect of continuous cropping on N content was minor. Meanwhile, N, P, and K contents in leaf litters increased due to continuous cropping, especially for those in the third generation plantation. As a result, the recovery rates of N, P, and K in the third generation were significantly lower than those in the first and the second generations (P<0.05), respectively. Moreover, the recovery rate of K was significantly higher than those of N and P (P<0.05), respectively. The stoichiometric ratios of C/N, C/P, and N/P in leaf litters were generally higher than those in mature leaves, respectively. The ratios of N/P and C/P in mature leaves of the third-generation plantation were obviously higher than those of the first and the second generations, however, there were no significant differences among C/N ratios in mature leaves of three generation plantations. With the increase of continuous cropping generations, no obvious variation trend was observed on stoichiometric ratios of C, N, and P in leaf litters. The ratios of N/P and C/P in leaf litters of the first generation were significantly higher than those of the second and the third generations (P<0.05), respectively, while the C/N ratio of the second generation was significantly higher than those of the first and the third generations (P<0.05).[Conclusion]Overall, continuous cropping could reduce the contents of P and K in mature leaves, increase N, P, and K contents in leaf litters, and reduce the nutrient recovery ratio of Populus×euramericana ‘Neva’. The internal circle of nutrients was therefore influenced. In addition, continuous cropping could reduce the decomposition rate of litters and affect the variations of C, N, and P contents in the soil by reducing N/P and C/P ratios in leaf litters.

Key words: continuous cropping, nutrient recovery, Populus×euramericana ‘Neva’, stoichiometry