Soil Carbon density and Aggregates Stability under Three Types'
Plantation Trees on Weibei Dryland, China
Afforestation has been implemented on a large scale in the Loess Plateau
of China since 1999. This paper aimed to judge the influence of
plantation tree types on soil aggregate stability and carbon stocks. The
results showed that : (1)the content of soil organic matter and
macro-aggregates, the water stability of aggregates were significantly
higher in P. tabuliformis plantation compared with R. pseudoacacia and
M. pumila plantations, conversely, the content of soil calcium carbonate
in P. tabuliformis plantation was the lowest; (2) the content of soil
organic matter and organic carbon density were significantly negatively
correlated with soil depth, while soil carbonate calcium and in-organic
carbon density fluctuated with the increasing of soil depth; (3)
compared with topsoil, subsoil was important carbon sink because there
were more in-organic carbon; (4) Aggregate organic carbon increased
while inorganic carbon decreased with the increasing of aggregate size
respectively. We concluded that: (1) R. pseudoacacia played a more
important role in soil carbon sequestration compared with P.
tabuliformis; while P. tabuliformis was more beneficial to improve soil
organic matter and soil structure; (2) subsoil and in-organic carbon
were important carbon sinks compared with topsoil and organic carbon;
(3) the bigger water stable aggregates having the higher content of soil
organic matter and the lower carbonate calcium.