Effects of precipitation on soil acid phosphatase activity in three successional forests in southern China

Q. Deng,W. Huang,G. Zhou,J. Liu,D. Zhang

doi:10.5194/bg-8-1901-2011

Abstract

Abstract. Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of organic P mineralization potential in soils. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment with precipitation treatments (no precipitation, natural precipitation and doubled precipitation) in three successional forests in southern China was carried out. The three forests include Masson pine forest (MPF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (MEBF). Results showed that driven by seasonality of precipitation, changes in soil acid phosphatase activities coincided with the seasonal climate pattern, with significantly higher values in the wet season than in the dry season. Soil acid phosphatase activities were closely linked to forest successional stages, with enhanced values in the later stages of forest succession. In the dry season, soil acid phosphatase activities in the three forests showed a rising trend with increasing precipitation treatments. In the wet season, soil acid phosphatase activity was depressed by no precipitation treatment in the three forests. However, doubled precipitation treatment exerted a significantly negative effect on it only in MEBF. These results indicate that the potential transformation rate of organic P might be more dependent on water in the dry season than in the wet season. A decrease in organic P turnover would occur in the three forests if there was a drought in a whole year in the future. More rainfall in the wet season would also be adverse to organic P turnover in MEBF due to its high soil moisture.

Highlights

Phosphorus (P) limitation to forest primary productivity and other ecosystem processes is widespread in tropical forests (Attiwill and Adams, 1993)
mixed forest (MF) and monsoon evergreen broadleaved forest (MEBF) showed significantly greater annual mean soil moisture than Masson pine forest (MPF) (P < 0.01), but there was no significant difference between MF and MEBF
This necessarily resulted in high soil acid phosphatase activities in MF and MEBF as this enzyme partly originates from microbes

Summary

Introduction

Phosphorus (P) limitation to forest primary productivity and other ecosystem processes is widespread in tropical forests (Attiwill and Adams, 1993). The production of phosphatase would be increased when the requirement for P by forest ecosystems is increased (Clarholm, 1993; Olander and Vitousek, 2000). These enzymes play an important role in maintaining and controlling the rate of P cycling in forest ecosystems. Acid phosphatase is predominant in forest soils due to their pH optima (Juma and Tabatabai, 1988). Its activity can provide useful information on organic P mineralization potential and biological activity of soils (Speir and Ross, 1978; Dick and Tabatabai, 1993; Kramer and Green, 2000). Acid phosphatase activity has been used as an indicator in several studies to evaluate P limitation in forest ecosystems (Schneider et al, 2001; Gress et al, 2007)

Methods

Results

Discussion

Conclusion