干旱区生态环境知识资源中心

Litter phosphorus (P) return is important to maintain the P cycle and balance in the sandy land of arid areas. In this study, we determined the loss and return of litter P in sand dune areas and elucidated their relationship. We investigated litter production and litter P amount, and simulated leaf litter moving dynamics to understand the relationships between the loss of litter P and the total litter P, and between the return of litter P and the total litter P in active (AD), semi-stabilized (SSD) and stabilized (SD) dunes in Inner Mongolia, northeastern China. The vegetation litter P was 12.6, 94.5, and 201.6 mg P/m(2) in AD, SSD, and SD, respectively. A significant movement and loss of leaf litter P with time occurred on the three types of sand dunes. As a result, the loss of P was 7.4, 46.9, and 69.8 mg P/m(2) and the return of P was 5.5, 47.6, and 131.8 mg P/m(2) in AD, SSD, and SD, respectively. The relationship between both loss and return of P and total litter P in AD, SSD, and SD was revealed by linear regression. The slope of the regression line indicated the rate of loss or return of litter P. From AD to SD, the loss rate showed a declining slope (0.52, 0.32, and 0.17 for AD, SSD, and SD, respectively), and the return rate showed a rising slope (0.48, 0.67, and 0.83 for AD, SSD, and SD, respectively). The loss of litter P should be regarded in the local management of vegetation and land in sand dune areas. Improved vegetation restoration measures are necessary to decrease litter P loss to maintain the stability of ecosystems in sand dune areas.