Effects of aluminum toxicity induced by acid deposition on pine forest ecosystem in Longli of Guizhou Province, Southwestern China

Abstract

The effects of acid deposition on pine forest ecosystems in Longli of Guizhou Province, southwestern China are studied using indoor experiments and model simulations. Indoor experiments are designed to explore the aluminum toxicity on pine seedlings, and the long-term soil acidification model (LTSAM) and a terrestrial biogeochemistry model (CENTURY) are used to simulate the influences of acid deposition on pine forest ecosystems. The indoor experiment results of aluminum toxicity show that aluminum ions in solution limit plant growth and acid deposition enhances this effect by facilitating the release of aluminum ions from the soil. Pine seedling biomass and root elongation decrease as the aluminum concentration increases. The results of model simulations show that the soil chemistry varies significantly with different changes in acid deposition. When the acid deposition increases, the pH value in the soil solution decreases and the soil Al 3+ concentration increases. The increased acid deposition also has negative impacts on the forest ecosystem, i.e., decreases plant biomass, net primary productivity (NPP) and net CO 2 uptake. As a result, the soil organic carbon (SOC) decreases because of the limited supply of decomposition material. Thus acid deposition need be reduced to help protect the forest ecosystems.

Plant species richness or soil fertility: which affects more the productivity of Scots pine in Central Europe?

“…Specifically, this concerns Podzols being much poorer than both other studied soil units, which can be seen when nutrients' stocks as well as contents of fine textural classes are compared (Table 4). The revealed for Podzols negative relation between pH and pine productivity could be found controversial, because usually the adverse effect of low soil pH on the tree growth is highlighted (Kidd & Proctor 2001, Jönsson et al 2003, Zhang et al 2016, which is linked to the toxic effect of aluminum in strongly acidic environments on tree roots (Jönsson et al 2003, Gruba 2004, Zhang et al 2016. However, the stated negative relation between pH and SI values could be explained first by the beneficial influence of low pH on pine ectomycorrhizal fungi, a large number of which have pH optima at ca.…”

“…Acidification is also highlighted to be the essential factor affecting the forest productivity. Usually, the adverse effect of decreasing soil pH on the tree growth has been reported (Kidd & Proctor 2001, Jönsson et al 2003, Zhang et al 2016, which is linked to the release of aluminum to soil solution in strongly acidified environment, and its subsequent toxic impact on tree roots (Jönsson et al 2003, Gruba 2004, Zhang et al 2016). On the other hand, for some environments the opposite relation was found; namely, low pH was positively related to biomass production in tropical forest ecosystems (Fujii 2014).…”

Identification of candidate genes conferring tolerance to aluminum stress in Pinus massoniana inoculated with ectomycorrhizal fungus

“…1; Table 1). Since high Al concentrations (> 1 mM) were reported in forest soils in southern China [30,55], it is evident that P. massoniana suffers from Al toxicity in the field. Various [60][61][62][63] and it can facilitate the regeneration and plantation of Pinus seedlings in Al contaminated areas.…”

“…1 ; Table 1 ). Since high Al concentrations (> 1 mM) were reported in forest soils in southern China [ 30 , 55 ], it is evident that P. massoniana suffers from Al toxicity in the field. Various ectomycorrhizal fungi have been shown to improve Pinus growth performance and tolerance to diverse biotic and abiotic stresses, including Al toxicity [ 4 , 6 , 25 – 28 ].…”

“…Aluminum (Al) toxicity driven by soil acidification is a long-lasting problem causing forest dieback in many regions of the world [29], particularly in China where natural and forest plantations are declining [30]. Acid rain and anthropogenic soil acidification caused by long-range air pollution and intensive uses of acid-forming fertilizers create nutrient depletion in the soil and accelerate bioavailability of toxic elements such as Al 3+ [31][32][33].…”