In order to understand the distribution characteristics of soil aggregate nutrients under different vegetation restoration time

we selected typical eroded red soil sample plots with different restoration time (0 year

5 years

10 years

15 years

30 years and 80 years)

which located in Hetian Town

Changting County

Fujian Province of subtropical China in this paper. Nutrient contents of different soil aggregate sizes (＞5 mm

2—5 mm

1—2 mm

0.5—1 mm

0.25—0.5 mm and ＜0.25 mm) with different depths of soil layers (0—20 cm and 20—40 cm) of sample plots were measured

and the correlation of nutrient contents between soil and aggregates were analyzed as well. The results are as follow: (1) The contents of organic carbon

total nitrogen

total phosphorus

total potassium

available phosphorus and available potassium within soil aggregates were 2.06 to 27.71 g/kg

0.54 to 2.12 g/kg

0.034 to 0.171 g/kg

2.20 to 6.89 g/kg

0.31 to 3.30 mg/kg and 7.35 to 85.71g/kg

respectively

with the process of vegetation restoration; (2) the contents of organic carbon

total nitrogen

total phosphorus and available phosphorus generally increased with the decreasing aggregate-size fraction (P＜0.05)

but the contents of total potassium and available potassium had no significant difference (P＞0.05); (3) during different aggregate size fractions

the contents of organic carbon

total nitrogen

total phosphorus and available phosphorus within soil aggregate generally increased with the years of vegetation restoration (P＜0.05)

while the content of total potassium firstly increased and decreased finally

and the content of available potassium showed a fluctuant increase tendency; (4) at the early period of vegetation restoration (0 and 5 years)

the nutrient contents of soil aggregate of 2 layers kept relatively consistent tendency

and soil aggregate nutrient contents in 0—20 cm soil layer were significantly higher than in 0—20 cm layer; (5) the decreasing order of contribute rate of different aggregate fractions to soil nutrient was (＞5 mm)＞(2—5 mm)＞(0.5—1 mm)＞(1—2 mm)＞(0.25—0.5 mm)＞(＜0.25 mm)

and the contribute rate of ＞2 mm aggregates were 34.18% to 49.93%; soil nutrient contents were highly related to the ＞0.25 mm aggregates ((P＜0.01). In summary

soil aggregate nutrient content increases obviously associated with the improvement of soil structure and the promotion of nutrient sequestration

while soil erosion were controlled by the measure of vegetation restoration.