Environmental Engineering Reference
In-Depth Information
Chapter 5
E
FFECTS OF
O
RGANIC
A
CIDS ON
N
UTRIENTS
M
OBILIZATION OF
S
OILS WITH
D
IFFERENT
S
OIL
A
CIDITY IN THE
C
OASTAL
Z
ONE
,
S
HANDONG
,
C
HINA
Gang Xu
1,#
, Junna Sun
1,3,#
, Yingchun Lv
1
and Hong-Bo Shao
1,2,
1
Key Laboratory of Coastal Biology and Bioresources Utilization,
Yantai Institute of Coastal Zone Research (YIC),
Chinese Academy of Sciences (CAS), Yantai, P. R. China
2
Institute for Life Sciences, Qingdao University of Science and Technology (QUST),
Qingdao, P. R. China
3
Graduate University of Chinese Academy of Sciences (CAS), Beijing, P.R. China
A
BSTRACT
The exudation of organic acids by plant roots has been universally accepted to be a
significant soil nutrients mobilization mechanism. The aim of our study was to determine
the effect of different organic acids type, concentrations, reaction time and pH, in
association with soil types on nutrients (P, Ca and Mg) releases from soils with different
soil acidity. Our results showed that low concentrations of organic acids (<2 mmol/L)
exhibited little effect on the nutrients releases from soils (especially for high pH soil).
However, nutrients releases were greatly increased when a relatively high concentration
of organic acids were added into soil. Generally, P, Ca and Mg solubility was negatively
related to soil pH, and P solubility was positively related to Ca and Mg releases except
for oxalic acid due to the P precipitation with Ca and Mg. Meanwhile, the pH of organic
acids affected P release: low pH was favorable for P release although high pH seem to
have inhibited P release in high soil pH. Reaction times of organic acids with soil were
important for nutrients release although the involved mechanisms need to be further
investigated. Our results suggested that organic acids greatly increased P, Ca and Mg
transformation and availability in soils.
Keywords:
Organic acids, phosphorus, pH, nutrient mobilization, soil quality
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