“Grain for Green” Project is one of the main measures to control soil and water loss on the Loess Plateau. Discussing the impact of returning farmlands to forests on the stability of soil aggregates and soil erodibility could provide a scientific basis for ecological restoration and benefit evaluation of soil and water conservation on the Loess Plateau. In this study
the Robinia pseudoacacia L. forests with different planting years (5 years
10 years
15 years
20 years
25 years and 30 years) were selected as the research object
and the farmland was used as the control to study the dynamic changes of soil aggregate stability and soil erodibility in 0-30 cm soil layers after returning farmlands to forests
and the study also explored the relationship between soil erodibility and soil aggregate stability. The results showed that: (1) The content
mean weight diameter and geometric mean diameter (GMD) of water-stable aggregates>0.25 mm increased with the increasing of planting years
which increased by 32%~79%
32%~98% and 2%~60%
respectively
compared with that of farmland. (2) The fractal dimension of soil aggregates decreased with the increasing of restoration ages
which decreased by 0.6%~6.0% compared with that of before returning farmland. Soil organic matter increased with the increasing of restoration ages
increased by 8.4%~38.9% compared with that of farmlands. (3) Soil erodibility factor K increased with the increasing of soil layer
but decreased gradually with the increasing of restoration ages
and decreased by 1.0%
2.7%
3.6%
3.9%
5.0% and 7.9%
respectively
with the increasing of restoration ages. (4) After the conversion of farmland to forest
the fractal dimension of soil aggregates and the content of water-stable aggregates>0.25 mm were the main driving factors for the change of soil erodibility. The aboveground biomass indirectly affected soil erodibility through affecting the fractal dimension of soil aggregates and the content of water-stable aggregates>0.25 mm
and the total effect was the largest. The study suggested that the increase of soil aboveground biomass after returning farmlands to forests played an important role in the formation and stability of soil aggregates and the reduction of soil erodibility
and returning farmlands to forests significantly improved the stability of aggregates and reduced soil erodibility.
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Response of Soil Erodibility on the Loess Plateau to the Grain to Green Program
Stability of Deep Soil Organic Carbon of Dam Land on the Loess Plateau
Effects of Maize Intercropping with Hairy Vetch and Rye on Soil Organic Carbon and Its Fractions
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Related Author
HUANG Wanyun
ZHAO Yunge
LIU Baoyuan
WANG Shanshan
YANG Kai
SUN Hui
GU Kangmin
ZHOU Shixuan
Related Institution
Institute of Soil and Water Conservation, Northwest A&F University, Yangling
College of Natural Resources and Environment, Northwest A&F University, Yangling
College of Forestry, Northwest A&F University, Yangling
State Key Laboratory of Soil Erosion and Dry-land Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling
College of Resources and Environment, China Agricultural University