ISSN 1002-0160/CN 32

Pe
do
s
phe
r
e 15(
6)
: 7
07
-71
5, 2
0
0
5
I
SS
N 1
0
0
2
-
01
6
0/
CN 3
2
-
1
31
5
/
P
⑥ 2005 SCI
ENCE PRESS, BEI
JI
NG
Ef
f
ects of Accel
erated Soi
l Erosi
on on Soi
l Nutri
ent Loss
Af
t
er Def
or
es
t
ati
on on t
he Loes
s Pl
at
eau*
1
ZHENG Fen-
Li
St
at
e Ke
y Lab
o
r
at
or
y o
f Soi
l Er
o
s
i
o
n and Dr
yl
and Far
mi
ng i
n Lo
e
s
s Pl
at
e
au, I
ns
t
i
t
ut
e o
f So
i
l and Wat
e
r Cons
e
r
v
at
i
on,
Ch
i
ne
s
e Ac
ade
my o
f Sc
i
e
nc
e
s a
nd Mi
ni
s
t
r
y o
f Wa
t
e
r Re
s
o
ur
c
e
s
, Ya
n
g
l
i
n
g 7
1
21
0
0 (
Ch
i
na
)
. E-
ma
i
l
: f
l
z
h@i
s
wc
.
a
c
.
c
n
(
Re
c
e
i
v
e
d Ma
y 1
1
, 2
0
0
5
; r
e
v
i
s
e
d S
e
pt
e
mbe
r 2
5, 2
0
0
5
)
ABSTRACT
S
oi
l e
r
os
i
on and nut
r
i
e
nt l
o
s
s
e
s on ne
wl
y-
de
f
or
e
s
t
e
d l
ands i
n t
he Zi
wul
i
ng Re
gi
on on t
he Loe
s
s Pl
at
e
au of Chi
na we
r
e
moni
t
o
r
e
d t
o qua
nt
i
t
a
t
i
ve
l
y e
v
al
uat
e t
he e
fe
c
t
s of ac
c
e
l
e
r
a
t
e
d s
oi
l e
r
os
i
on, c
aus
e
d by de
f
or
e
s
t
at
i
on, on or
gani
c ma
t
t
e
r
,
ni
t
r
o
g
e
n a
nd ph
o
s
pho
r
u
s l
o
s
s
e
s
. Ei
g
h
t n
a
t
ur
a
l r
uno
fp
l
o
t
s we
r
e e
s
t
a
bl
i
s
h
e
d o
n t
h
e l
o
e
s
s
i
a
l h
i
l
l s
l
o
pe
s r
e
pr
e
s
e
n
t
i
ng di
fe
r
e
n
t
e
r
o
s
i
on pa
t
t
e
r
ns of do
mi
na
n
t e
r
o
s
i
o
n pr
oc
e
s
s
e
s i
n
c
l
u
di
n
g s
he
e
t
, r
i
l
l a
n
d s
ha
l
l
o
w gul
l
y (
s
i
mi
l
a
r t
o e
ph
e
me
r
a
l gul
l
y)
. S
e
di
me
n
t
s
ampl
e
s we
r
e c
ol
l
e
c
t
e
d af
t
e
r e
ac
h e
r
os
i
ve r
ai
nf
al
l e
ve
nt
. Re
s
ul
t
s s
ho
we
d t
hat s
oi
l nut
r
i
ent
s l
os
s
e
s i
nc
r
e
a
s
e
d wi
t
h an i
nc
r
e
as
e
of e
r
os
i
on i
nt
e
ns
i
t
y. Li
ne
a
r r
e
l
at
i
ons be
t
we
e
n t
he l
os
s
e
s of or
gani
c ma
t
t
e
r
, t
ot
al N, NH4
-
N, and a
v
ai
l
abl
e P and e
r
os
i
o
n
i
n
t
e
ns
i
t
y we
r
e f
ound. Nu
t
r
i
e
n
t c
on
t
e
nt pe
r un
i
t a
moun
t o
f e
r
o
de
d s
e
di
me
n
t de
c
r
e
a
s
e
d f
r
o
m t
he s
he
e
t t
o t
he s
ha
l
l
o
w gul
l
y
e
r
os
i
on z
one
s
, whe
r
e
a
s t
ot
al nut
r
i
e
nt l
o
s
s i
nc
r
e
a
s
e
d. Compar
e
d wi
t
h t
ops
oi
l
, nut
r
i
en
t
s i
n e
r
ode
d s
e
di
me
nt we
r
e e
nr
i
c
he
d,
e
s
pe
c
i
al
l
y a
v
ai
l
abl
e P and NH4
-
N. The i
nt
e
ns
i
t
y of s
oi
l nut
r
i
e
nt l
os
s
e
s was al
s
o c
l
os
e
l
y r
e
l
a
t
e
d t
o s
oi
l e
r
os
i
on i
nt
e
ns
i
t
y and
pa
t
t
e
r
n wi
t
h t
he mos
t s
e
v
e
r
e s
o
i
l e
r
o
s
i
o
n a
nd n
ut
r
i
e
n
t l
os
s oc
c
u
r
r
i
ng i
n t
he s
h
a
l
l
o
w gul
l
y c
ha
n
ne
l
s o
n l
o
e
s
s
i
a
l hi
l
l s
l
o
pe
s
.
Th
e
s
e r
e
s
e
a
r
c
h indi
f
ng
s wi
l
l he
l
p t
o i
mpr
o
v
e t
he und
e
r
s
t
a
n
di
ng o
f t
he r
e
l
a
t
i
o
n be
t
we
e
n a
c
c
e
l
e
r
a
t
e
d e
r
o
s
i
on pr
o
c
e
s
s a
f
t
e
r
de
f
or
e
s
t
a
t
i
on and s
oi
l qual
i
t
y de
gr
a
da
t
i
on and t
o de
s
i
gn be
t
t
e
r e
c
-en
o
vi
r
onme
nt
al r
e
habi
l
i
t
a
t
i
on s
c
he
me
s f
or t
he Lo
e
s
s
Pl
at
eau.
Ke
y Wo
r
d
s
: a
c
c
e
l
e
r
a
t
e
d s
oi
l e
r
os
i
on, de
f
or
e
s
t
at
i
on, e
r
os
i
on i
nt
e
ns
i
t
y, Loe
s
s Pl
a
t
e
au, nut
r
i
e
nt l
os
s
I
NTRODUCTI
ON
S
o
i
l nut
r
i
e
nt l
o
s
s c
a
us
e
d饰 a
c
c
e
l
e
r
a
t
e
d s
o
i
l e
r
o
s
i
o
n a
f
t
e
r de
f
o
r
e
s
t
a
t
i
o
n i
s be
c
o
mi
ng mo
r
e o
f a c
o
nc
e
r
n
i
n t
he wo
r
l
d. A l
a
r
g
e numbe
r o
f s
t
udi
e
s ha
v
e be
e
n de
s
i
gne
d t
o i
n
ve
s
t
i
g
a
t
e s
o
i
l nut
r
i
e
nt l
os
s wi
t
h e
r
o
de
d
s
e
d
i
me
n
t
s
. F
o
r i
ns
t
a
nc
e
, Fl
a
na
g
a
n a
n
d Fo
s
t
e
r (
1
9
8
9
) f
o
und t
h
a
t n
u
t
r
i
e
n
t
s i
n e
r
o
de
d s
e
di
me
n
t we
r
e
s
i
g
n
i
ic
f
a
n
t
l
y e
n
r
i
c
he
d; Mo
n
k
e e
t a
l
. (
1
9
7
7
) s
ho
we
d t
ha
t n
u
t
r
i
e
n
t e
n
r
i
c
h
me
n
t r
a
t
i
o
s i
n s
e
d
i
me
n
t r
a
n
g
e
d
f
r
o
m 1
.
2 t
o 2
.
3
; Yo
u
n
g e
t a
l
. (
1
9
8
6
) s
h
o
we
d t
ha
t n
u
t
r
i
e
n
t e
n
r
i
c
hme
n
t i
n e
r
o
d
e
d s
e
d
i
me
n
t d
e
c
r
e
a
s
e
d
wi
t
h a
n i
n
c
r
e
a
s
i
n
g r
u
no
fr
a
t
e a
nd s
us
pe
n
de
d s
e
di
me
n
t c
o
nc
e
n
t
r
a
t
i
o
n; a
nd J
o
h
ns
o
n a
n
d Ba
k
e
r (
1
9
8
3
,
1
9
8
4
) a
f
t
e
r a
n
a
l
yz
i
n
g o
v
e
r 6
5
0 i
n
di
v
i
dua
l r
u
no
fs
a
mpl
e
s f
r
o
m c
o
r
n a
nd s
o
y
be
a
n ie
f
l
d
s d
i
s
c
o
v
e
r
e
d t
ha
t
Kj
e
l
da
h
l
-
N a
nd t
o
t
a
l P c
o
n
t
e
n
t
s i
n s
e
di
me
n
t we
r
e c
l
o
s
e
l
y r
e
l
a
t
e
d t
o s
e
di
me
n
t c
o
n
c
e
n
t
r
a
t
i
o
n i
n r
u
no
f.
I
n a
dd
i
t
i
o
n, S
h
a
r
p
l
e
y e
t a
l
. (
1
9
9
1
) me
a
s
u
r
e
d e
r
o
s
i
o
n a
n
d a
s
s
o
c
i
a
t
e
d N a
n
d P l
o
s
s
e
s wi
t
h s
e
d
i
me
n
t u
n
d
e
r
na
t
ur
a
l r
a
i
nf
a
l
l a
s a
fe
c
t
e
d b
y ma
na
g
e
me
nt a
nd f
o
und t
ha
t bo
t
h N a
nd P c
o
nt
e
n
t
s i
n s
e
di
me
nt we
r
e
s
t
r
ongl
y r
e
l
at
e
d t
o s
e
di
me
nt c
onc
e
nt
r
at
i
on of i
ndi
vi
dua
l r
unofe
ve
nt
s
.
D
ur
i
ng t
he pa
s
t 1
0 y
e
a
r
s i
n t
he Uni
t
e
d St
at
e
s muc
h e
fo
r
t ha
s be
e
n de
v
ot
e
d t
o s
t
udyi
ng t
he e
fe
c
t
s
o
n s
o
i
l qua
l
i
t
y whe
n c
on
ve
r
t
i
ng v
e
g
e
t
a
t
i
o
n t
o c
ul
t
i
v
a
t
i
on, s
uc
h a
s t
he Co
ns
e
r
v
a
t
i
o
n Re
s
e
r
v
e Pr
o
g
r
a
m
(
CRP)
. Th
e r
e
s
u
l
t
s s
h
o
we
d t
h
a
t c
o
n
v
e
r
t
i
n
g CRP l
a
n
d
s t
o c
u
l
t
i
v
a
t
i
o
n s
i
g
n
i
ic
f
a
n
t
l
y i
n
c
r
e
a
s
e
d r
u
n
o
fa
n
d
e
r
o
s
i
o
n a
nd a
c
c
e
l
e
r
a
t
e
d s
o
i
l q
ua
l
i
t
y d
e
g
r
a
da
t
i
o
n (
Da
v
i
e a
nd La
n
t
, 1
9
9
4
; Gi
l
l
e
y e
t a
l
.
, 1
9
9
6, 1
9
9
7
a, b)
.
I
n Chi
na, s
t
udi
e
s o
f s
o
i
l e
r
o
s
i
o
n a
nd s
o
i
l de
g
r
a
da
t
i
o
n ha
v
e be
e
n mo
s
t
l
y c
o
nduc
t
e
d i
n s
e
ve
r
e
l
y e
r
ode
d
r
e
g
i
o
ns
, s
u
c
h a
s t
h
e r
e
d
-
s
o
i
l r
e
g
i
o
n (
Ti
a
n e
t a
l
.
, 2
0
0
3
; Zh
a
n
g e
t a
l
.
, 2
0
0
4
) a
nd t
h
e Lo
e
s
s Pl
a
t
e
a
u (
Ta
n
g
e
t a
l
.
, 1
9
8
7
; Ba
i e
t a
l
.
, 1
9
9
1
; Li
, 1
9
9
0; Pe
ng a
nd Wa
n
g, 1
9
9
5
)
. Ho
we
v
e
r
, l
i
t
t
l
e a
t
t
e
n
t
i
o
n ha
s be
e
n pa
i
d t
o
qua
n
t
i
f
yi
ng s
o
i
l nut
r
i
e
nt l
os
s a
nd s
o
i
l qua
l
i
t
y de
t
e
r
i
o
r
a
t
i
o
n a
f
t
e
r de
f
o
r
e
s
t
a
t
i
on, e
s
pe
c
i
a
l
l
y o
n t
he Loe
s
s
*
'
Pr
o
j
e
c
t s
u
pp
o
r
t
e
d b
y t
h
e Na
t
i
o
n
a
l Na
t
u
r
a
l Sc
i
e
n
c
e F
o
u
n
da
t
i
o
n o
f Chi
n
a (
No. 9
0
3
0
2
0
0
1
) a
n
d t
h
e Na
t
i
o
n
a
l Ke
y Ba
si
c
Re
s
e
a
r
c
h Suppor
t Fou
nda
t
i
o
n (
NKBRS
F) o
f Chi
na (
No.
2
0
0
2
CB1
1
1
5
0
2
)
万方数据
708
F. L. M ENG
Pl
a
t
e
a
u whe
r
e s
o
i
l qua
l
i
t
y de
t
e
r
i
o
r
a
t
i
o
n c
a
us
e
d by a
c
c
e
l
e
r
a
t
e
d s
oi
l e
r
o
s
i
o
n a
f
t
e
r de
f
o
r
e
s
t
a
t
i
o
n ha
s be
c
o
me
one of t
he mai
n envi
r
onment
al i
s
s
ues.
T
he Zi
wul
i
ng Se
c
o
nda
r
y Fo
r
e
s
t Ar
e
a o
n t
he Loe
s
s Pl
a
t
e
a
u, whe
r
e v
e
g
e
t
a
t
i
o
n ha
s e
xpe
r
i
e
nc
e
d c
o
m-
pl
e
t
e de
s
t
r
uc
t
i
o
n, na
t
ur
a
l r
e
s
t
o
r
a
t
i
on, a
nd de
s
t
r
uc
t
i
o
n a
ga
i
n dur
i
ng t
he pa
s
t 1
4
0 y
e
a
r
s o
r s
o, pr
o
v
i
de
d
a na
t
ur
a
l r
e
s
e
a
r
c
h s
i
t
e t
o e
v
a
l
ua
t
e i
mpa
c
t
s o
f v
e
g
e
t
a
t
i
o
n c
ha
ng
e on r
e
g
i
o
nal e
nvi
r
o
nme
nt
a
l qua
l
i
t
y. The
o
bj
e
c
t
i
v
e o
f t
hi
s r
e
s
e
a
r
c
h wa
s t
o q
ua
nt
i
f
y t
he e
fe
c
t
s o
f a
c
c
e
l
e
r
a
t
e
d s
o
i
l e
r
o
s
i
o
n c
a
us
e
d by de
f
o
r
e
s
t
a
t
i
o
n
o
n s
o
i
l o
r
g
a
n
i
c ma
t
t
e
r (
OM)
, t
o
t
a
l n
i
t
r
o
g
e
n (
TN)
, a
mmo
n
i
a n
i
t
r
o
g
e
n (
NH4
-
N) a
n
d a
v
a
i
l
a
b
l
e p
h
o
s
p
h
o
r
u
s
(
P) l
o
s
s
e
s
, b
y mo
ni
t
o
r
i
ng s
o
i
l e
r
o
s
i
o
n a
nd n
ut
r
i
e
n
t l
o
s
s i
n n
e
wl
y
-
d
e
f
o
r
e
s
t
e
d l
a
n
ds i
n t
he Zi
wu
l
i
n
g Re
g
i
o
n.
Thi
s i
nf
o
r
ma
t
i
o
n wi
l
l he
l
p t
o i
mpr
o
v
e unde
r
s
t
a
ndi
ng o
f t
he r
e
l
a
t
i
o
ns
hi
p be
t
we
e
n a
c
c
e
l
e
r
a
t
e
d s
oi
l e
r
o
s
i
o
n
a
f
t
e
r de
f
o
r
e
s
t
a
t
i
o
n a
nd s
o
i
l qua
l
i
t
y de
g
r
a
da
t
i
o
n.
M ATERI
ALS AND M ETHODS
St
ud
y s
i
t
e d
e
s
c
r
i
pt
i
o
n
D
ur
i
ng t
he pa
s
t 1
40 y
e
a
r
s
, e
xc
e
pt i
n t
he Zi
wul
i
ng Ar
e
a, na
t
ur
a
l ve
g
e
t
a
t
i
o
n i
n mo
s
t o
f t
he r
e
g
i
o
ns
o
n t
he Loe
s
s Pl
a
t
e
a
u ha
s be
e
n c
o
mpl
e
t
e
l
y de
s
t
r
o
ye
d. The Zi
wul
i
ng Fo
r
e
s
t Ar
e
a, whi
c
h oc
c
upi
e
s a
bo
ut
2
3 0
0
0 km2
, i
s t
he s
o
l
e s
e
c
o
n
da
r
y f
o
r
e
s
t r
e
g
i
o
n o
n t
h
e Lo
e
s
s Pl
a
t
e
a
u. I
t i
s s
i
t
ua
t
e
d i
n t
he hi
l
l
y r
e
g
i
o
n
be
t
we
e
n t
h
e Do
n
g
z
hi a
nd Luo
c
h
ua
n Pl
a
t
e
a
us (
La
t
i
t
ud
e 3
3
0 5
0
'
-
3
6
0 5
0
' N a
nd Lo
ng
i
t
ud
e 1
0
7
0 3
0
'
-1
0
9
0
4
0
' E)
. Abo
ut 1
4
0 y
e
a
r
s a
g
o, t
h
e e
c
o
-
e
n
v
i
r
o
nme
n
t o
f t
h
e Zi
wul
i
ng Re
g
i
o
n wa
s s
i
mi
l
a
r t
o mo
s
t hi
l
l
y
-
g
ul
l
y r
e
g
i
o
ns on t
he Lo
e
s
s Pl
a
t
e
a
u t
oda
y
, i
. e
. v
e
g
e
t
a
t
i
o
n wa
s c
o
mpl
e
t
e
l
y de
s
t
r
o
y
e
d; s
o
i
l e
r
os
i
o
n was
s
e
v
e
r
e
; a
n
d t
o
p
s
o
i
l (
h
u
mi
c h
o
r
i
z
o
n
) wa
s wa
s
h
e
d a
wa
y
. At t
h
a
t t
i
me
, a wa
r b
e
t
we
e
n t
h
e Ha
n a
n
d Hu
i
na
t
i
o
na
l
i
t
i
e
s o
c
c
ur
r
e
d, l
e
a
di
ng t
o a po
pul
a
t
i
o
n e
xodus
. Si
nc
e t
he
n s
e
c
o
nda
r
y f
o
r
e
s
t v
e
g
e
t
a
t
i
o
n ha
s be
e
n
de
v
e
l
o
pi
ng.
The ie
f
l
d e
xpe
r
i
me
nt wa
s c
o
nduc
t
e
d a
t t
he Fuxi
an Obs
e
r
v
a
t
o
r
y f
o
r So
i
l Er
o
s
i
o
n a
nd Ec
o
-
e
nvi
r
o
nme
nt
,
whi
c
h wa
s e
s
t
a
bl
i
s
he
d i
n 1
9
8
9 (
Ta
ng e
t a
l
.
, 1
9
9
3
)
. Thi
s o
bs
e
r
v
a
t
o
r
y i
s l
o
c
a
t
e
d o
n t
h
e e
a
s
t
e
r
n s
l
o
pe o
f t
he
Zi
wul
i
ng Se
c
o
nda
r
y Fo
r
e
s
t Re
gi
o
n. Loe
s
s c
o
v
e
r
e
d l
o
w mount
a
i
ns a
nd hi
l
l
s
, e
l
e
v
a
t
i
o
ns r
a
ng
i
ng f
r
o
m 9
2
0
t
o 16
8
3 m wi
t
h a r
e
l
a
t
i
v
e h
e
i
g
h
t o
f 1
0
0 t
o 1
5
0 m, a
n
d a g
u
l
l
y d
e
n
s
i
t
y o
f 4
.
5 k
m k
m-2 c
h
a
r
a
c
t
e
r
i
z
e t
h
e
l
a
ndf
o
r
ms
. The a
nnua
l a
v
e
r
a
g
e t
e
mpe
r
a
t
ur
e i
s 6 t
o 1
0 '
C, whi
l
e pr
e
c
i
pi
t
a
t
i
o
n r
a
ng
e
s f
r
o
m 6
0
0 t
o 7
0
0
mm, i
n whi
c
h 6
0% f
a
l
l
s f
r
om J
une t
o Se
pt
e
mbe
r
. The ma
xi
mum pr
e
c
i
pi
t
a
t
i
on i
n a mo
nt
h c
a
n a
c
c
o
unt
f
o
r 2
5
% t
o 4
0% o
f t
he t
o
t
a
l a
nnua
l r
a
i
nf
a
l
l
, a
nd t
he ma
xi
mum da
i
l
y r
a
i
nf
a
l
l i
s 87 mm.
I
n t
h
e f
o
r
e
s
t a
r
e
a
, t
he ma
i
n t
r
e
e s
pe
c
i
e
s we
r
e o
a
k (
Qu
e
r
c
u
s l
i
a
o
t
u
n
g
e
ns
i
s Ko
i
d
z
umi
)
, po
p
l
a
r (
Po
pu
l
u
s
d
a
v
i
d
i
a
n
a Do
d
e
) a
n
d b
i
r
c
h (
Be
t
u
l
a pl
a
t
y
p
h
y
l
l
a S
u
k
a
c
z
e
v)
. Th
e c
a
n
o
p
y d
e
n
s
i
t
y o
f t
h
e t
i
mbe
r f
o
r
e
s
t wa
s
mo
r
e t
ha
n 7
0%, a
nd a2 t
o 5 c
m de
e
p l
i
t
t
e
r l
a
ye
r c
o
v
e
r
e
d t
he s
o
i
l s
ur
f
a
c
e
. Thi
s s
o
i
l had a
n o
bvi
ous
o
r
g
a
ni
c hor
i
z
o
n wi
t
h we
l
l
-
de
v
e
l
o
pe
d s
o
i
l a
g
g
r
e
ga
t
e
s a
nd de
ns
e r
oo
t
i
ng s
ys
t
e
m. Ho
we
ve
r
, a
r
g
i
l
l
i
c ho
r
i
z
o
ns
wer
e not obvi
ous.
Si
t
e sel
ect
i
on and dat
a col
l
ect
i
on
T
o
po
g
r
a
p场 i
n t
he hi
l
l
y-
g
ul
l
y r
e
g
i
o
n o
f t
he Loe
s
s Pl
a
t
e
a
u i
s c
ompl
e
x. Al
o
ng wi
t
h s
l
o
pe l
e
ng
t
h, s
l
o
pe
g
r
a
di
e
nt i
nc
r
e
a
s
e
d, i
. e
.
, t
he s
l
o
pe s
ha
pe wa
s c
o
nv
e
x. Sl
o
pe
s we
r
e v
e
r
y s
t
e
e
p r
a
ng
i
ng f
r
o
m 30
-1
20 i
n t
he
s
h
e
e
t e
r
o
s
i
o
n d
o
mi
n
a
n
t z
o
n
e (
t
o
p s
l
o
pe
)
, 1
2
0
-
2
5
0 i
n t
h
e r
i
l
l e
r
o
s
i
o
n d
o
mi
n
a
n
t z
o
n
e (
mi
dd
l
e s
l
o
pe
)
, t
o
1
8
0
-
3
5
0 i
n t
h
e s
ha
l
l
o
w g
u
l
l
y e
r
o
s
i
o
n d
o
mi
n
a
n
t z
o
n
e (
d
o
wn
s
l
o
pe
)
. To i
f
nd r
e
p
l
i
c
a
b
l
e s
l
o
pe s
e
c
t
i
o
n
s a i
f
e
l
d
s
ur
ve
y wa
s unde
r
t
a
ke
n t
o s
e
l
e
c
t a r
e
pr
e
s
e
nt
a
t
i
v
e hi
l
l
s
l
o
pe t
o e
s
t
a
bl
i
s
h r
unofp
l
o
t
s a
c
c
o
r
di
ng t
o t
ypi
c
a
l
t
o
po
g
r
a
phi
c
a
l f
e
a
t
u
r
e
s
. Ei
g
h
t r
u
no
fp
l
o
t
s
, i
nc
l
udi
ng t
wo c
o
n
t
r
o
l pl
o
t
s (
wo
od
l
a
nd) a
nd s
i
x de
f
o
r
e
s
t
e
d
pl
o
t
s
, we
r
e c
o
ns
t
r
uc
t
e
d o
n hi
l
l
s
l
o
pe
s a
s s
ho
wn i
n Ta
bl
e I
. Fo
r t
he
s
e r
uno
fp
l
ot
s
, t
he s
a
me do
mi
na
n
t
e
r
o
s
i
o
n z
o
ne ha
s t
he s
i
mi
l
a
r g
e
o
mo
r
phi
c a
nd e
r
o
s
i
v
e c
o
ndi
t
i
o
ns
. Ea
c
h pl
o
t wa
s s
ur
r
o
unde
d wi
t
h c
o
nc
r
e
t
e
bl
o
c
k bo
r
de
r
s (
e
xt
e
ndi
ng 1
0 c
m a
bo
v
e t
he s
u
r
f
a
c
e a
nd 1
0 c
m be
l
o
w t
he s
u
r
f
a
c
e
) f
o
r r
uno
fp
l
o
t i
s
o
l
a
t
i
o
n.
A t
r
o
ug
h f
o
r r
uno
fc
o
l
l
e
c
t
i
o
n wa
s i
ns
t
a
l
l
e
d a
t t
he o
ut
l
e
t
.
Fo
r e
a
c
h r
uno
fe
v
e
nt s
t
o
r
a
g
e c
o
nt
a
i
ne
r
s we
r
e us
e
d t
o c
o
l
l
e
c
t r
uno
fv
o
l
ume f
r
o
m e
a
c
h r
uno
fp
l
o
t
.
M ul
ti
-
sl
ot di
vi
sors were i
nstal
l
ed i
n case one col
l
ect
i
on contai
ner coul
d not hol
d al
l of the r
unof i
n an
万方数据
709
SOI
L EROSI
ON EFFECT ON SOI
L NUTRI
ENT LOSS
TABLE I
Ar
r
ange
ment of nat
ur
al r
unof pl
ot
s
Runofp
l
ot Loc
a
t
i
on
Dom i
nated erosi
on zone
4
Bare and f
al
l
ow
101 5-32
5
100 5-26
5
100 5-26
11.
7
424 26-35
13.
6
995.
2 5-35
14.
2
965.
8 5-35
6
8
1
了
2.
5
6
3
6
Bar
e and f
al
l
ow
2.
5
3
7石
5-12
64 12-26
2.
5
0
2
5
Bar
e and f
al
l
ow
Veget
at
i
on l
and
Bar
e and f
al
l
ow
门} 0
4
2
3
Bare and f
al
l
ow
m m2
.6 A
2
Bar
e and f
al
l
ow
Lengt
h Wi
dt
h Ar
e
a Sl
ope gr
adi
ent
5
5
1一 2
一
1
Top s
l
ope She
e
t e
r
os
i
on
Mi
ddl
e s
l
ope Ri
l
l e
r
os
i
on z
one
Top
-
mi
ddl
e s
l
ope She
e
t+ r
i
l
l e
r
os
i
on z
one
Top-
mi
ddl
e s
l
ope Shee
t+ r
i
l
l er
os
i
on z
one
Top-
mi
ddl
e s
l
ope Cont
r
ol
Do
wn-
s
l
ope Shal
l
o
w gul
l
y e
r
os
i
on
Whol
e hi
l
l
s
l
ope She
e
t+ r
i
l
l+s
hal
l
ow
Land use
(
t
o
p t
o bo
t
t
o
m) gu
l
l
y e
r
o
s
i
on
Whol
e hi
l
l
s
l
ope Cont
r
ol
Ve
ge
t
at
i
on l
and 80.
2
(
t
o
p t
o bo
t
t
o
m)
e
x
t
r
e
me r
a
i
nf
a
l
l e
v
e
n
t
. Du
r
i
ng o
bs
e
r
v
a
t
i
o
n pe
r
i
o
ds f
r
o
m 1
9
8
9 t
o 2
0
0
3
, pr
i
o
r t
o t
he r
a
i
n
y s
e
a
s
o
n (
i
n
Ap
r
i
l
)
, a s
ho
v
e
l wa
s us
e
d t
o t
ur
n t
h
e s
o
i
l i
n t
he r
uno
fp
l
o
t
s t
o a d
e
pt
h o
f 2
0 c
m a
c
c
o
r
di
n
g t
o l
o
c
a
l
l
y
t
r
a
d
i
t
i
o
n
a
l c
u
l
t
i
v
a
t
i
o
n pr
a
c
t
i
c
e
s
. Twi
c
e a y
e
a
r c
o
r
e s
a
mp
l
e
r
s we
r
e us
e
d t
o t
a
k
e t
o
ps
o
i
l s
a
mpl
e
s (
2
0 c
m
d
e
e
p) f
o
r n
u
t
r
i
e
n
t t
e
s
t
s
, i
.
e
.
, t
hr
e
e da
y
s a
f
t
e
r t
i
l
l
a
g
e i
n Ap
r
i
l a
nd a
f
t
e
r r
a
i
n
s a
t t
h
e e
n
d o
f Oc
t
o
be
r
.
Ac
c
o
r
di
ng t
o t
he t
o
po
g
r
a
p帅 a
nd e
r
o
s
i
o
n pa
t
t
e
r
ns
, iv
f
e s
a
mpl
i
ng s
i
t
e
s a
l
o
ng t
he s
l
o
pe l
e
ng
t
h i
n t
he
s
he
e
t e
r
o
s
i
o
n do
mi
na
nt z
o
ne
, s
e
v
e
n s
a
mpl
i
ng s
i
t
e
s i
n t
he r
i
l
l e
r
o
s
i
o
n do
mi
na
nt z
o
ne
, a
nd 1
8 s
a
mpl
i
ng
s
i
t
e
s i
n t
he s
ha
l
l
o
w g
u
l
l
y e
r
o
s
i
o
n do
mi
na
n
t z
o
ne (
s
i
x i
n t
h
e s
ha
l
l
o
w g
ul
l
y c
ha
nne
l a
nd 1
2 a
t bo
t
h s
i
de
s o
f
t
he s
ha
l
l
o
w g
u
l
l
y c
ha
nn
e
l
) we
r
e c
ho
s
e
n. I
n a
dd
i
t
i
o
n, s
o
i
l s
a
mp
l
e
s f
r
o
m wo
o
d
l
a
nds (
Pl
o
t
s 5 a
n
d 8
, Ta
b
l
e
I
) t
h
a
t c
o
r
r
e
s
p
o
n
d
e
d t
o t
h
e s
a
mp
l
e l
o
c
a
t
i
o
n
s o
f d
e
f
o
r
e
s
t
e
d p
l
o
t
s we
r
e c
o
l
l
e
c
t
e
d
.
A
f
t
e
r e
a
c
h r
uno
f
f e
v
e
n
t
, t
he wa
t
e
r l
e
v
e
l i
n e
a
c
h c
o
n
t
a
i
ne
r wa
s me
a
s
ur
e
d t
o c
a
l
c
ul
at
e r
uno
fv
o
l
ume
,
a
nd a
f
t
e
r mi
xi
ng r
o
und wi
t
h am
uddl
e
r
, s
e
di
me
nt s
a
mpl
e
s we
r
e c
o
l
l
e
c
t
e
d f
r
o
m e
a
c
h c
o
nt
a
i
ne
r
. Af
t
e
r
2
4 h o
f s
e
di
me
nt
a
t
i
o
n, t
he c
l
e
a
r wa
t
e
r wa
s po
ur
e
d o
ut o
f t
he bo
t
t
l
e
s
. The
n t
he s
e
di
me
nt wa
s dr
i
e
d饰
a
i
r o
r s
u
nl
i
g
h
t a
nd t
h
e a
i
r
-
dr
i
e
d s
o
i
l s
a
mpl
e
s we
r
e u
s
e
d f
o
r l
a
bo
r
a
t
o
r
y a
na
l
ys
i
s
. Or
g
a
n
i
c ma
t
t
e
r (
OM)
wa
s d
e
t
e
r
mi
n
e
d u
s
i
n
g t
h
e me
t
h
o
d o
f Wa
l
k
l
e
y a
n
d Bl
a
c
k (
Bi
g
h
a
m, 1
9
9
6
)
, t
o
t
a
l n
i
t
r
o
g
e
n (
TN) (
Kj
e
l
d
a
h
l
d
i
g
e
s
t
) a
n
d NH4
-
N (
2
.
0 mo
l L一
1 KCl e
x
t
r
a
c
t
a
n
t
) we
r
e e
s
t
a
b
l
i
s
h
e
d u
s
i
n
g a
n a
u
t
o
ma
t
e
d i
o
n a
n
a
l
y
z
e
r
,
a
n
d a
v
a
i
l
a
bl
e ph
o
s
p
h
o
r
us (
0.
5 mo
l L一1 Na
HC03 e
x
t
r
a
c
t
a
n
t
) wa
s a
n
a
l
y
z
e
d wi
t
h c
o
l
o
r
i
me
t
r
y
.
Cal
cul
at
i
ons
A
nnual
l
y i
n Apr
i
l f
or e
a
c
h r
uno
fp
l
o
t s
o
i
l OM, t
o
t
a
l N, NH4
-
N a
nd a
v
a
i
l
a
bl
e P c
o
nt
e
nt
s we
r
e t
a
k
e
n a
s
r
e
f
e
r
e
nc
e v
a
l
ue
s t
o c
a
l
c
ul
a
t
e t
he nut
r
i
e
nt e
nr
i
c
hme
n
t r
a
t
i
o o
f t
he s
e
di
me
n
t f
o
r t
ha
t y
e
a
r
. The di
fe
r
e
nc
e
s
i
n annua
l v
a
l
ue
s be
t
we
e
n Apr
i
l a
nd Oc
t
o
be
r o
f e
a
c
h y
e
a
r f
o
r e
a
c
h r
uno
fp
l
o
t we
r
e c
a
l
c
ul
a
t
e
d t
o a
s
s
e
s
s
nutri
ent l
oss
es.
I
n t
hi
s s
t
udy
, t
he nut
r
i
e
nt e
nr
i
c
hme
n
t r
a
t
i
o i
n e
r
ode
d s
e
di
me
nt f
r
o
m e
a
c
h r
uno
fp
l
o
t i
n e
a
c
h o
bs
e
r
-
v
a
t
i
o
n y
e
a
r wa
s de
ine
f
d a
s a s
pe
c
i
a
l nut
r
i
e
nt c
o
nt
e
nt i
n e
r
ode
d s
e
di
me
nt
s c
o
mpa
r
e
d t
o t
he c
o
r
r
e
s
po
ndi
ng
s
o
i
l r
e
f
e
r
e
nc
e v
a
l
ue i
n Apr
i
l o
f t
ha
t y
e
a
r f
o
r t
he s
a
me pl
o
t
. The
s
e nut
r
i
e
nt e
nr
i
c
hme
n
t r
a
t
i
o
s we
r
e us
e
d
t
o qua
nt
i
f
y nut
r
i
e
nt l
o
s
s a
s
s
oc
i
a
t
e
d wi
t
h di
fe
r
e
nt e
r
o
s
i
o
n i
nt
e
ns
i
t
i
e
s a
nd pa
t
t
e
r
ns
.
LSD Te
s
t wa
s pe
r
f
o
r
me
d t
o de
t
e
r
mi
ne whe
t
he
r s
i
g
ni
ic
f
a
n
t di
fe
r
e
nc
e
s i
n t
he nut
r
i
e
n
t l
o
s
s a
nd nut
r
i
e
nt
e
nr
i
c
hme
n
t r
a
t
i
os i
n e
r
ode
d s
e
di
me
nt a
mo
ng s
he
e
t e
r
o
s
i
o
n do
mi
na
n
t z
one
, r
i
l
l e
r
o
s
i
o
n do
mi
na
nt z
o
ne
,
a
nd e
phe
me
r
a
l gul
l
y e
r
o
s
i
o
n do
mi
nan
t z
o
ne
.
RESULTS AND DI
SCUSSION
Re
l
at
i
ons
h咖 b
e
t
we
e
n s
oi
l e
r
os
i
on and nut
r
i
e
nt l
os
s
One m ajor c
t o
f e
r
os
i
o
n i
s l
o
s
s of s
oi
l nut
r
i
e
nt
s al
ong wi
t
h e
r
ode
d s
e
di
me
nt
s
. By a
na
l
yz
i
ng
i
m pa
万方数据
F. L. ZHEN G
710
r
ai
nf
a
l
l e
ve
nt
s
, t
he r
e
l
at
i
ons
hi
p be
t
we
e
n
Loess Pl
ateau of
quant
i
ied. Al
f
s
o,i
n t
he ne
wl
y de
f
o
r
e
s
t
e
d l
a
nds on the n eroded sedi
m ents af
nut
ri
ent cont
ent
si
t
er erosive
and nutri
ent l
oss m ay
t
o
ps
o
i
l v
a
r
i
e
d g
r
e
a
t
l
y wi
t
h e
r
os
i
v
e e
v
e
n
t
s a
nd t
i
me due t
o s
e
v
e
r
e s
o
i
l l
os
s
.
a
t
e
s a
nd e
r
o
s
i
o
n pa
t
t
e
r
ns t
he r
uno
fp
l
o
t
s wi
t
h di
fe
r
e
n
t s
i
z
e
s
Addi
t
i
ona
l
l
y, due t
o di
fe
r
e
nc
e
sm erosion r
had di
ferent nutri
ent contents. I
n t
hi
s s
t
udy
, nut
r
i
e
nt l
os
s
e
s c
a
us
e
d饰 s
he
e
t
, r
i
l
l a
nd s
ha
l
l
o
w gul
l
y
we
r
e me
a
s
ur
e
d s
e
pa
r
a
t
e
l
y
.
Chi
na, nut
r
i
e
nt c
ont
ent
amount decreased f
r
om
Tabl
e II showed that f
or rai
nf
al
l eventsnutri
ent cont
e无
tpe
u
t s
e
me
t
Per rU
un
li
n
l
毛s
ed
Qi
l
m en
l
l
ta
i
ncreas
ed. Thi
s
z
one
s
, whi
l
e t
hepr
o
por
t
i
on of nut
r
i
e
ntloss s
he
e
t t
o s
ha
l
l
o
w g
ul
l
y do
mi
na
nt
Data i
n Tabl
e
wa
s c
a
us
e
d by t
he i
nc
r
e
a
s
e
d s
e
di
me
nt yi
e
l
d f
r
o
m s
he
e
t t
o s
ha
l
l
o
w g
ul
l
yerosion zones. c
o
nt
r
i
but
e
d a
ppr
o
x
i
ma
t
e
l
y 7
0
% o
f t
he
I
I
I r
e
v
e
al
e
d t
ha
t nut
r
i
e
nt l
os
s
e
s f
r
om r
i
l
l and s
hal
l
ow gul
l
y
TABLE II
Nut
r
i
ent
s i
n e
r
oded s
edi
ment
s f
r
om s
he
et
, r
i
l
l
, and s
hal
l
ow gul
l
y e
r
os
i
on zones under s
eve
r
al r
ai
nf
al
l e
vent
s
Da
t
e Ra
i
n
- 1
3
0
a
)
f
al
l
Dom i
nant
Er
o
s
i
o
n Ra
t
i
o
b
l OM
Reduc- Total
duc
- P'
l
Reduc
- NH4-
N Re
erosion
rate
t
i
onb
) N
t
i
onbl
t
i
onb)
pattern
t km一2 ti
mes
m m m m
g kg-1%
g kg-1%
6
.
8
0
2
.
OJ
4
8
.
5
1} 3
0 4
…
21.
96
4
…
129.
2
1
1
7
.
8
97.
4
7
23.
08
8
20.
51
4
5
3
99.
2
7
5
1工 0
1
l l
ee
9 8
『
1 9
11.
85
112.
9
12.
62
27.
41
92.
4
28.
48
l
a 5
5
0
阿‘
Ql q山 1上
.
18 31.
99
4
.
11 11 11 11 1工 11 飞1 ,工 n
自
6
峭
I
.
48 18.
92
5
 ̄
0
脚了 9
11 2
0
2
.
26
3
.
…
9
4
11 9
11 9
6
2
1立 2
.
19 38.
14
22.
38
4
5
2.
35
124.
8
27.
7
5
Shal
l
o
w gul
l
y 1
757
36.
46
18.
93
…
2003
100.
9
3
6
1.
67
40.
59
6
4
Ri
l
l 1252
25.
82
5
5
29,
22.
47
44.
10
…
Sheet erosi
on 748
27.
43
117.
8
6
5
2 0.
34
Jul
. 14.
36.
78
29.
41
.
Shal
l
o
w gul
l
y 1
443
0
32.
82
9
5
1996
158.
8
.
Ri
l
l 9637
18.
32
34.
49
6
6
29,
92.
7
43.
09
.
She
et er
osi
on 526
36.
77
2
8
1.
15
Jul
. 108 4.
48
19.
86
.
Shal
l
o
w gul
l
y 11
66
113.
4
4
4
1996
18.
06
.
1.
63
Ri
l
l 424
5
4
13,
31.
54
141.
5
.
Sheet er
osi
on 260
9
7
0.
17
Jul
. 10 0
7
15.
77 39.
72
7.
63
片1 8
2 9
Shal
l
ow gul
l
y 1
220
22.
29 14.
79
mg kg-1%
5
5
1995
.
26.
16
25,
Sheet er
osi
on 160
Ri
l
l 302
1.
89
0.
45
Aug. 13.6 ,土 一
1
mi
n-1
mg kg-1%
9.
31
14.
04
'
)
Ma
x
i
mu
m 3
0
-
mi
n r
a
i
n
f
a
l
l i
n
t
e
n
s
i
t
y
. b
) Co
mp
a
r
e
d t
o s
h
e
e
t e
r
o
s
i
o
n
. `
)
Av
a
i
l
a
b
l
e p
h
o
s
p
h
o
r
o
u
s
.
TABLE II
I
Nut
r
i
ent l
os
s
es f
r
om di
fe
r
ent er
os
i
on zones f
or s
el
ec
t
ed year
s
Year Erosi
on zone Soi
l nutri
ent
OM
Total N
NH4-
N
%
1995
Sheet erosi
on domi
nant zone
Ri
l
l er
osi
on domi
nant zone
Shal
l
o
w gul
l
y e
r
os
i
on domi
nant z
one
1996
28.
6
27.
8
24.
1
Ri
l
l erosi
on domi
nant zone
33.
1
31.
2
31.
4
32.
6
Shal
l
o
w gul
l
y e
r
os
i
on domi
nant z
one
36.
1
40.
2
40.
8
43.
3
25.
4
25.
8
23.
8
32.
2
32.
6
4
.
QD
.
1上 4
3 4
6
…
S
3
4
八
0
5
2 3
几‘ 3
…
8
2
4
2
6
4
,工 3
q‘ q‘ 八
0
8
片t
.
1
匕
5
…
…
8
1上 3
…
33.
3
6
.
1主
4
】0
8
2
3
8
}
1
4
1
丫
万方数据
.
Shal
l
ow gul
l
y er
os
i
on domi
nant z
one
0
4
Ri
l
l erosi
on domi
nant zone
8
Sheet erosi
on domi
nant zone
4
3
M ean
.
Shal
l
ow gul
l
y e
r
os
i
on domi
nant zone
23.
9
5
2
Ri
l
l erosi
on domi
nant zone
42.
4
3 1上
OJ 4
Sheet erosi
on domi
nant zone
4
2
2003
力
0
Shal
l
ow gul
l
y er
os
i
on domi
nant z
one
.
Ri
l
l erosi
on domi
nant zone
q‘ 0
3 4
Sheet erosi
on domi
nant zone
6
30.
8
6
2
1997
Sheet erosi
on dom i
nant zone
22.
1
24.
1
34.
3
32.
4
43.
6
43.
5
SOI
L EROSI
ON EFFECT ON SOI
L NUTRI
ENT LOSS
711
t
o
t
a
l nut
r
i
e
nt l
o
s
s o
n hi
l
l
y s
l
o
pe
s
.
A l
i
ne
ar r
e
l
at
i
ons
hi
p be
t
we
e
n nut
r
i
e
nt l
os
s and
i
nt
e
ns
i
t
y f
o
r t
he l
oe
s
s
i
a
l hi
l
l
s
l
o
pe
s c
o
ul
d be
expresses as:
(
1
)
NL= aEa
nt
ens
i
t
y
whe
r
e NL i
s nut
r
i
e
nt l
os
s(
a i
s t
he pr
o
po
r
t
i
o
na
l c
oe
f
ic
f
i
e
n
t
; a
nd Ea i
s t
heerosion i
k
g k
m-
2
)
;
(
t k
m-
2
)
.
The pr
o
po
r
t
i
o
na
l c
o
e
ic
f
i
e
n
t
, a, be
t
we
e
n n
ut
r
i
e
n
t l
o
s
s i
n
t
e
ns
i
t
y a
nd e
r
o
s
i
o
n i
n
t
e
ns
i
t
y f
o
r a
) t
he s
he
e
t
erosi
on zone,b
nd c
) t
he c
o
mbi
ne
d s
he
e
t
, r
i
l
l a
nd s
ha
l
l
o
w
) t
he
-
,
c
o
mbi
ne
d s
he
e
t a
nd r
i
l
lerosion zones,a
ues wer
e f
ound f
or di
ferent nutr
i
ents f
rom
e I
V. Di
ferent 。 val
gul
l
yerosi
on zones was gi
ven i
n Tabl
di
ssi
mi
l
ar eros
i
on domi
nant zones.
TA BLE IV
Pr
opor
t
i
o
nal c
ons
t
ant
,“,be
t
we
e
n nut
r
i
ent l
os
s and s
oi
l e
r
os
i
on and t
he c
or
r
e
l
at
i
on c
oe
fi
c
i
e
nt r
Erosi
on zone Soi
l nutri
ent
Q r 食 r 仪 r
Sheet erosi
on zone
Combi
ned s
heet+ r
i
l
l
.
erosio n zones
on +
Combi
ned sheet+ r
i
l
lerosi
s
hal
l
ow gul
l
y e
r
os
i
on zone
s
OM
Total N
NH4-
N
P
24.
332
1.
3307
0.
1163
0.
0056
0.
9979
0.
9674
0.
9090
0.
9726
20.
026
1.
1057
0.
0975
0.
0051
0.
9999
0.
9997
0.
9996
0.
9997
17.
114
1.
1838
0.
1195
0.
0053
0.
9574
0.
9864
0.
9794
0.
9875
Nut
ri
ent enri
chment i
n eroded sedi
ment
Se
v
e
r
a
l r
e
s
e
a
r
c
he
r
s ha
v
e r
e
po
r
t
e
d t
ha
t N a
nd P i
n e
r
ode
d s
e
di
me
nt we
r
e s
i
g
ni
ic
f
a
nt
l
y e
nr
i
c
he
d
(
Mo
n
k
e e
t a
l
.
, 1
9
7
7
; Fl
a
n
a
g
a
n a
n
d F
o
s
t
e
r
, 1
9
8
9
; Yo
u
n
g e
t a
l
.
, 1
9
8
6
)
. Da
t
a f
r
o
m t
h
i
s s
t
ud
y a
l
s
o s
ho
we
d
t
ha
t OM, t
o
t
a
l N, a
v
a
i
l
a
bl
e P and NH4
-
N we
r
e g
r
e
a
t
l
y e
nr
i
c
he
d i
n e
r
ode
d s
e
di
me
nt
s
. The e
n
r
i
c
hme
nt
r
a
t
i
o
s f
o
r OM, t
ot
a
l N, NH4
-
N a
nd a
v
a
i
l
a
bl
e P f
r
o
m t
he s
he
e
t e
r
o
s
i
o
n z
o
ne
, t
he c
o
mbi
ne
d s
he
e
t a
nd r
i
l
l
e
r
o
s
i
o
n z
o
ne
s
, a
nd t
he c
o
mbi
ne
d s
he
e
t
, r
i
l
l and s
ha
l
l
o
w g
ul
l
y e
r
o
s
i
o
n z
o
ne
s we
r
e t
a
bul
a
t
e
d i
n Ta
bl
e
s V,
VI
, a
nd VI
I
, r
e
s
pe
c
t
i
v
e
l
y. The
s
e da
t
a i
ndi
c
a
t
e
d t
ha
t a
v
a
i
l
a
bl
e P ha
d t
he hi
g
he
s
t e
nr
i
c
hme
nt r
a
t
i
o wi
t
h
v
a
l
ue
s r
a
ng
i
ng f
r
o
m 1
.
4
2 t
o 3.
6, f
o
l
l
o
we
d饰 NH4
-
N wi
t
h v
a
l
ue
s r
a
ng
i
ng f
r
o
m 1
.
1
3 t
o 1
.
9
4. The e
nr
i
c
h-
me
nt r
a
t
i
o
s o
f OM a
nd t
o
t
a
l N i
n s
e
di
me
n
t we
r
e f
r
o
m 0.
97 t
o 1
.
4
3 a
nd 0.
8
9 t
o 1
.
2
9, r
e
s
pe
c
t
i
v
e
l
y
. The
e
n
r
i
c
hme
nt r
a
t
i
os
, r
e
g
a
r
dl
e
s
s o
f di
f
f
e
r
e
nt g
e
o
g
r
a
phi
c
a
l l
o
c
a
t
i
o
ns
, we
r
e s
i
mi
l
a
r t
o t
he r
e
s
ul
t
s o
f Mo
nk
e
e
t a
l
. (
1
9
7
7
)
. Ho
we
v
e
r
, t
h
e e
n
r
i
c
hme
n
t r
a
t
i
o
s i
n t
h
e s
he
e
t e
r
o
s
i
o
n z
o
ne f
r
o
m t
hi
s s
t
u
dy we
r
e h
i
g
he
r
t
W t
ho
s
e o
bt
a
i
ne
d f
r
o
m l
o
ng
-
t
e
r
m c
u
l
t
i
v
a
t
e
d a
r
e
a
s i
n t
h
e s
e
v
e
r
e
l
y e
r
o
d
e
d r
e
g
i
o
n o
f Lo
e
s
s Pl
a
t
e
a
u (
Li
,
1
9
9
0
)
, i
nd
i
c
a
t
i
ng a
c
c
e
l
e
r
a
t
e
d n
ut
r
i
e
n
t l
o
s
s i
n t
h
e be
g
i
nn
i
ng s
t
a
g
e
s a
f
t
e
r d
e
f
o
r
e
s
t
a
t
i
o
n. I
n a
dd
i
t
i
o
n, t
h
e
TA BLE V
Nutri
ent cont
ents i
n er
oded sedi
ments and thei
r enri
chment rati
os f
r
om the sheet er
osi
on zone
Erosi
on rate
Nutri
ent content i
n sedi
m ent
Nutri
ent enri
chm ent rati
o i
n sedi
m ent
NH4-
N Avai
l
abl
e P
OM
Total N
—
mg k
g-1_
NH4-
N
Avai
l
abl
e P
2
3
2
3
3
4
9
7
‘
6
0
.
1土
2
q‘ 6
3
6
2
1上 9
4
6
7
4
2
…
…
91 2
7
3
一
.上 1上 11
.
.
3
…
0
6
3
一
上
0
1
ll C ) 11
2.
13
.
.
2.
37
OM
11 1上 11 ,1
西
1
.
上
只 Qd 3 4
11 2 q山 7
1
.1
:
11
8
1上 9
6
23.
36
一
1
21.
48
3
26.
19
…
八‘ 0
3
一
1
31.
54
3
24.
08
,1 0
5
6
114.
8
110.
4
4
3
5
124.
8
5
万方数据
158.
8
…
.
255
4
1
了
q自 2
690
3
4
7 526
L L L
95
133.
8
8
24
4
26.
16
1土 11 0
5.
45
4
133.
5
2
1.
37
9
160
…
23.
99
.
7.
17
0
2
128.
2
}
了
3
1.
55
11
2 418
一
.上
g k
g
-1
11 1上 1工 一
1
g k
g-1
t km-2
Total N
F. L. ZHENG
712
TABLE VI
Nut
r
i
ent c
ont
ent
s i
n er
oded s
edi
ment
s and thei
r enri
chment r
at
i
os f
r
om the combi
ned s
heet and r
i
l
l er
osi
on zones
Erosi
on r
ate Nutri
ent content i
n sedi
ment Nutri
ent enri
chment rati
o i
n sedi
ment
Tot
al N NH4-
N
3
3
曰
1
工
t 0
11 2
1上
2
5
1.
79
…
.
4
1.
57
OM
,1
2
0
6
,
.
8
3
9
2
曰
土
门
‘ 6
11 0
…
一
.上
4
1上 8
0
曰
土
口J 4
11 2
:
2
4
1土
3
一
1
】
勺
6
…
CO
刁
ee l} 1
0
;
.
0
0
一
ee
1上
0
4
2
0
3
1
1
1上 1上 一
.上 1上
1一 4
可
悦1 2
11
0
0
0
…
16.
43
…
.
18.
13
,1
户
95.
4
20.
04
9
8
.
05
94.
5
4
.
03
11
213
11
1 169
21.
50
11
97.
4
19.
30
1上
1.
10
18.
92
1
.上
11218
21.
47
一
.1
108.
6
g kg-1
T〕
七
al N NH4-
N Avai
l
abl
e P
,1
21
424
OM
1上
127.
2
Q口 4
C洲
2
11 3
37
5.
11
4
103.
5
}
匕
21
-
5
9
1
…
134.
2
7
15
20
…
359
k
g-1
1上 1上 1土
671
9
t km-2
Avai
l
abl
e P
TABLE VII
Nut
r
i
e
nt c
ont
e
nt
s i
n e
r
ode
d s
e
di
me
nt
s and t
he
i
r e
nr
i
c
hme
nt r
at
i
os f
r
om t
he c
ombi
ne
d s
he
e
t+ r
i
l
l+s
hal
l
o
w gul
l
y e
r
os
i
on
zo n es
Nutri
ent enri
chm ent rati
o i
n sedi
m ent
Erosi
on rate Nutri
ent content i
n sedi
m ent
Z
bt
al N NH4-
N
6
2
3
5
2
91 4
1土 2
…
4
9
1上 2
3
1
2
6
4
知
1 一 11
1上 3
1上 ,1
11 2
3
5
…
9
,上 5
}
1 9
9J 5
1上 一
.上 1上 }
土
11 一
ee
.
一
.1
ll q‘ 3
.
0口 阿了 }
0 3
1上 0
.
5
一
1
7
9
…
11
7
3
,1
6
1上 2
0
11 2
1上 1工 1上 0
3
2
67 77 16 32 42 17 22 63 55 16 45 69 24 54 21
.
11 ,1 2
4
1上 8
2
1土 .
1
.
4
0
17.
86
NH4-
N Avai
l
abl
e P OM
1上
11 9
0
0
9.
94
0
113.
9
8
23
0
6.
93
,上
121.
7
,土
10
10.
11
0
107.
2
:
97
1
7.
61
1
114.
8
0
23
…
7.
65
,1 1上 0
124.
6
…
11
.
11.
35
.
106.
2
1上 1土 11 1上 }
土
07
.
13.
41
.
181.
3
1书 0
35
8.
56
4
9
5
142.
8
…
21
4 7
1‘ 5
7 5
11.
65
4
3
9
135.
7
…
21
TotalN
.
12.
65
.
138.
0
.
43
8.
29
.
127.
1
.
20
1
13.
53
1上 1上 1l ll J
.上
136.
1
1
了 6
0 5
,1 9
35
1上 2
97
12.
59
8
7
7
776
130.
8
2
1981
29
0
9
2
7235
13.
77
2
4589
217.
4
21.
59
八‘
7853
17
L L L L L 已 L L
161
11
3310
一
.1
1182
12.
99
0 4 3
q‘ 11 9
1土 州
1 2
3735
1033
177.
1
g kg -I
11 2
4271
33
OM
2
4
9
2060
mg kg I_
k
g一I
L L L 工
8337
1土
2049
9
t km-2
Avai
l
abl
e P
1.
12
1.
08
1.
13
1.
12
1.
22
1.
22
1.
11
1.
32
1.
22
1.
21
1.
07
1.
26
1.
29
1, :;
3
enri
chment rati
os were di
ferent i
nt
he s
he
e
t e
r
os
i
on z
one, t
he c
ombi
ne
d s
he
e
t and r
i
l
l e
r
os
i
on z
one
s
,
a
nd t
he c
ombi
ne
d s
he
e
t
, r
i
l
l and s
ha
l
l
o
w g
ul
l
yerosion zones,s
ho
wi
ng g
r
e
a
t i
mpa
c
t o
f e
r
o
s
i
o
n pa
t
t
e
r
ns
on s
oi
l nutri
ent l
os
s.
Av
a
i
l
a
bl
e P i
n s
o
i
l de
c
r
e
a
s
e
d wi
t
h t
he de
f
o
r
e
s
t
e
d y
e
a
r f
r
o
m 1
9
89 t
o 1
9
9
5, whe
r
e
a
s t
hei
n creasi
ng
buted
t
r
e
nd o
f a
v
a
i
l
a
bl
e P e
n
r
i
c
hme
n
t r
a
t
i
o wa
s o
bs
e
r
v
e
d i
n e
r
o
de
d s
e
di
me
n
t (
Fi
g. 1
)
. Thi
s c
o
ul
d beattri
to theerosion r
a
t
e c
a
us
e
d b
y pe
r un
i
t o
f r
a
i
nf
a
l
l e
r
o
s
i
v
i
t
y t
ha
t i
n
c
r
e
a
s
e
d wi
t
h t
h
e de
f
o
r
e
s
t
e
d y
e
a
r (
Fi
g. 1
)
.
Soi
l nut
r
i
e
nt var
i
at
i
on wi
t
h t
he de
f
or
e
s
t
e
d ye
ar
S
he
e
t
, r
i
l
l a
nd s
ha
l
l
o
w g
ul
l
y e
r
o
s
i
o
n ha
v
e di
f
f
e
r
e
n
t s
o
i
l d
e
t
a
c
hme
n
t a
n
d t
r
a
n
s
po
r
t c
a
pa
c
i
t
i
e
s
; t
h
e
r
e
f
o
r
e
,
t
he
y po
t
e
nt
i
a
l
l
y ha
v
e di
f
f
e
r
e
nt i
mpa
c
t
s on s
oi
l nut
r
i
e
nt l
o
s
s
. Due t
o a
n i
nc
r
e
a
s
e of s
o
i
l e
r
odi
bi
l
i
t
y, t
he
e
r
o
s
i
o
n r
a
t
e c
a
us
e
d by pe
r uni
t o
f r
a
i
nf
a
l
l e
r
o
s
i
vi
t
y i
nc
r
e
a
s
e
d o
v
e
r t
i
me a
s s
ho
wn i
n Fi
g. 1
, i
. e
.
, t
he
e
r
o
s
i
o
n r
a
t
e i
n
c
r
e
a
s
e
d f
r
o
m 1
.
9
1 t k
m-
'
/
J m-
2 mm-
1 i
n 1
9
8
9 t
o 1
2
.
3
5 t k
m -
2
/
j M-
2 Mi
n一1 i
n 1
9
9
6
;
whi
l
e a
v
a
i
l
a
bl
e P i
n e
r
o
de
d s
e
di
me
nt de
c
r
e
a
s
e
d wi
t
h t
he de
f
o
r
e
s
t
e
d y
e
a
r e
xc
e
pt i
n 1
99
6 a
nd i
t de
c
r
e
a
s
e
d
f
r
o
m 2
3
.
8 mg k
g
-1 i
n t
h
e i
f
r
s
t y
e
a
r (
1
9
8
9
) t
o 8
.
2 mg k
g
-1 i
n 1
9
9
5
.
Ta
b
l
e VI
I
I s
ho
ws t
h
e r
e
duc
t
i
o
n o
f n
ut
r
i
e
n
t
s i
n t
he t
o
p
s
o
i
l (
2
0 c
m) i
n s
he
e
t
, r
i
l
l a
nd s
ha
l
l
o
w g
u
l
l
y
z
o
ne
s t
hr
e
e ye
a
r
s a
nd s
e
v
e
n ye
a
r
s a
f
t
e
r de
f
o
r
e
s
t
a
t
i
o
n c
o
mpa
r
e
d t
o aw
ood
l
a
nd c
o
nt
r
o
l
. I
n t
he s
he
e
t
万方数据
SOI
L EROSION EFFECT ON SOI
L NUTRI
ENT LOSS
713
e
r
o
s
i
o
n z
o
n
e
, a
v
e
r
a
g
e a
n
n
u
a
l s
o
i
l e
r
o
s
i
o
n r
a
t
e wa
s 6 7
7
5 t k
m-2 (
Ta
b
l
e I
X)
. Co
n
s
e
q
u
e
n
t
l
y
, f
o
rsheet
by
do
mi
na
nt e
r
o
s
i
o
n pa
t
t
e
r
ns a
f
t
e
r t
hr
e
e y
e
a
r
s o
f de
f
o
r
e
s
t
a
t
i
o
n OM d
e
c
r
e
a
s
e
d by 8
.
5
%-1
3.
9
%, t
o
t
alN 5
2
0一
和门」利
UOE 二0一
」Ued O一
q怕-
一
mA<
0
2
卜
。利
一
un」
gd^qPen.oe妇
佗Juo一
soJ
山
(
!
口义。)
尸
u。
妇
uoud。l
q.1
一
门>
V
犷EuJ,E早.
E戈忿之一
>一
s
o
J
。1
1
.
卜
u一
佗」
:
25
20
15
1.
5
10
1.
0
Avai
l
abl
e P cont
ent
0.
5
Er
osi
on r
at
e per uni
t of r
ai
nf
al
l er
osi
vi
t
y
Avai
l
abl
e P enr
i
chment r
at
i
o
0 `
1988
1990
1996
1992 1994
- 1 0
1998
Def
or
est
ed year
Fi
g. 1 Change
s of a
v
ai
l
abl
e P i
n e
r
ode
d s
e
di
me
nt
s
, e
r
os
i
on r
at
e c
aus
e
d by pe
r uni
t of r
ai
nf
a
l
l e
r
os
i
vi
t
y, and av
ai
l
a
bl
e
P e
nr
i
c
hme
nt r
at
i
os f
r
om t
he c
ombi
ne
d s
he
e
t
, r
i
l
l
, and s
hal
l
o
w gul
l
y e
r
o
s
i
on z
one
s f
or t
he de
f
o
r
e
s
t
e
d ye
ar
s
. Avai
l
abl
e P
e
nr
i
c
hme
nt r
a
t
i
o means t
he r
a
t
i
o of av
ai
l
abl
e P i
n s
e
di
me
nt t
o av
ai
l
abl
e P i
n t
ops
oi
l
; and e
r
os
i
on r
a
t
e pe
r uni
t of r
ai
nf
al
l
e
r
os
i
vi
t
y me
ans t
ha
t 1 mm of r
ai
nf
a
l
l pr
oduc
e
s e
r
os
i
ve e
ne
r
g
y pe
r uni
t ar
e
a c
aus
i
ng s
oi
l l
os
s
.
TA BLE VIII
erosion z
ones and the combi
ned
Nut
r
i
e
n
t s
t
a
t
u
s i
n t
he t
o
ps
oi
l (
2
0 c
m) o
f t
he s
he
e
t e
r
os
i
o
n z
on
e
, t
he c
o
mbi
ne
d s
he
e
t a
nd r
i
l
l
s
he
et
, r
i
l
l and s
hal
l
ow gul
l
y e
r
os
i
on zone
s be
f
or
e and af
t
e
r def
or
es
t
at
i
on
Erosi
on
Domi
nant
zo n e
erosion
Cont
r
ol (
woodl
and)
Years af
ter def
orestati
on
3 7
pattern
OM Tot
a
l N NH4
-
N pa
) OM Tot
al N NH4
-
N P OM Tot
al N NH4
-
N P
11
:
1上 8
1占 3
}
1
6
3
0
2
15.
71
4
3
15.
94
:
2
3
206.
4
8
7
17.
99
8
2
,1 2
188.
6
11
l 28.
25 1.
61
s
he
e
t
, r
i
l
l and Ril
l and 40.
46 1.
80
s
hal
l
o
w gul
l
y Ril
s
hal
l
ow gul
l
y
3
26.
70
 ̄
日}
176.
3
9
Sheet 29.
74 1.
47
Combi
ned
114.
0
19.
02 1.
14 118.
3 4.
58
0
28 79 1.
47
L L L
192.
3
1上
37.
74 1.
130.
4
5
s
he
e
t and r
i
l
l Ri
l
l
20.
28 1
5
8.
45
131.
0
…
181.
9
门
n
23.
55 1.
1
匕
Combi
ned Sheet
11
8.
78 21.
46 1
9
2 7
183.
6
mg k
g-1
一一 g k
g-1一 一mg吨-I-
5
23.
45 1.
g k
g-1
,上
Sheet
I__
一 一 mg kg一
2
Sheet
1上
- 3
1
一 gkg
116.
0
4.
64
103.
8
5.14
116.
0
2.
60 18.
76 1.
22
105.
2
2.
36
105.
4
2.
53 15.
25 1.
28
93.
6
2.
26
103.
6
2.
71 12.
56 0.
96
71.
0
2.
13
'
)
Av
a
i
l
a
b
l
e p
h
o
s
ph
o
r
o
u
s
.
TABLE I
X
Me
a
n e
r
o
s
i
o
n r
a
t
e
s a
nd s
t
a
n
da
r
d de
vi
a
t
i
o
ns (
SD) f
r
o
m s
he
e
t e
r
o
s
i
o
n z
on
e
, t
h
e c
ombi
ne
d e
r
o
s
i
o
n z
one
s o
f s
he
e
t a
nd r
i
l
l
,
and t
he c
ombi
ned e
r
os
i
on z
ones of s
he
et
, r
i
l
l and s
hal
l
ow gul
l
y er
os
i
on dur
i
ng t
he obs
er
vat
i
on per
i
ods
Erosi
on zone
Domi
nant erosi
on
M ean er
osi
on
Rati
o of erosi
on rate to that i
n
pat
t
er
n
r
a
t
e (
S
D)
the sheet erosi
on zone
t k
m-2 y
e
a
r
-1
Sheet
Sheet
Combi
ned sheet and r
i
l
l
Ri
l
l
Combi
ne
d s
he
et
, r
i
l
l and s
hal
l
ow gul
l
y
Ri
l
l and Sha
l
l
ow gul
l
y
万方数据
6
7
7
5 (
1
3
4
5
)
1
3
2
2
1 (
2
3
6
9
)
1
8
5
7
9 (
3
8
2
6
)
1.
0
1.
95
2.
74
F. L. M ENG
714
7
.
6
%-1
0.
2
%, NH4
-
N b
y 2
8.
3
%-
3
4.
2
%, a
nd a
v
a
i
l
a
bl
e P b
y 4
0.
5
%-6
1
.
9
%. S
e
v
e
n y
e
a
r
s a
f
t
e
r d
e
f
o
r
e
s
t
a
t
i
o
n
OM de
c
r
e
a
s
e
d by 1
8.
9%-3
6.
9%, t
o
t
a
l N饰 1
3.
0%-1
7.
0%, NH4
-
N b
y 3
5.
6
%-4
0.
3
%, a
nd a
v
a
i
l
a
bl
e P by
45.
1
%-65.
4%.
A
s t
h
e e
r
o
s
i
o
n r
a
t
e i
nc
r
e
a
s
e
d t
o 1
3 2
2
1 t k
m-2 y
e
a
r
-' i
n t
h
e c
o
mb
i
n
e
d s
h
e
e
t a
n
d r
i
l
l e
r
o
s
i
o
n z
o
n
e
s
a
nd t
o 1
8 5
7
9 t k
m-2 y
e
a
r
-' i
n t
he c
o
mbi
n
e
d s
h
e
e
t
, r
i
l
l a
n
d s
h
a
l
l
o
w g
u
l
l
y e
r
o
s
i
o
n z
o
n
e
s (
Ta
b
l
e I
X)
,
s
o
i
l n
u
t
r
i
e
n
t c
o
n
t
e
n
t
s o
f OM, t
o
t
a
l N, NH4
-
N a
n
d a
v
a
i
l
a
b
l
e P d
e
c
r
e
a
s
e
d a
c
c
o
r
d
i
n
g
l
y (
Ta
bl
e VI
I
I
)
. F
o
r
r
i
l
l d
o
mi
na
n
t e
r
o
s
i
o
n pa
t
t
e
r
n a
f
t
e
r t
hr
e
e y
e
a
r
s o
f de
f
o
r
e
s
t
a
t
i
o
n, OM de
c
r
e
a
s
e
d b
y 2
3.
7
%-
2
9
.
2
%, t
o
t
a
l
N b
y 1
6.
0
%-1
6.
8
%, NH4
-
N b
y 4
0.
7
%-
4
4.
1
%, a
nd a
v
a
i
l
a
bl
e P b
y 6
2.
1
%-7
4
.
0
%. Af
t
e
r s
e
v
e
n y
e
a
r
s o
f
de
f
o
r
e
s
t
a
t
i
o
n, OM de
c
r
e
a
s
e
d b
y 4
0.
8
-4
6.
0%, t
o
t
a
l N b
y 2
0.
5
%-2
1.
1
%, NH4
-
N by 46.
0
%-5
0.
4%, a
nd
a
v
a
i
l
a
bl
e P b
y 6
7
.
1
%-7
6
.
8
%. I
n t
he mo
s
t s
e
v
e
r
e
l
y e
r
o
d
e
d s
ha
l
l
o
w g
ul
l
y c
ha
nne
l
s
, s
o
i
l n
u
t
r
i
e
n
t l
o
s
s wa
s
t
he mo
s
t s
e
v
e
r
e
. Wi
t
h r
i
l
l a
nd s
ha
l
l
o
w g
ul
l
y do
mi
na
nt e
r
o
s
i
o
n pa
t
t
e
r
ns t
hr
e
e y
e
a
r
s a
f
t
e
r de
f
o
r
e
s
t
a
t
i
o
n,
reduct
i
ons i
n OM ,
e
s
pe
c
t
i
v
e
l
y
, a
nd
TN, NH4
-
N a
nd a
v
a
i
l
a
bl
e P we
r
e 61.
2
%, 3
3.
3%, 4
9.
8% a
nd 8
3.
0
%,r
i
ndi
cated
af
t
e
r s
e
ve
n ye
a
r
st
he
y we
r
e 6
9.
0
%, 4
6.
7
%, 6
5.
6
% a
nd 8
6.
6
%, c
o
r
r
e
s
pondi
ng
l
y
. The
s
eresults that nutr
i
ent l
oss o
c
c
ur
r
e
d r
a
pi
dl
y a
f
t
e
r de
f
o
r
e
s
t
a
t
i
o
n. The i
nt
e
ns
i
t
y of nut
r
i
e
nt l
o
s
son hi
l
l
s
l
ope
s
erosi
on
i
ncreas
ed as s
heeterosion s
hi
f
t
e
d t
o r
i
l
l e
r
os
i
o
n o
r s
ha
l
l
o
w g
ul
l
y e
r
o
s
i
o
n due t
o a
n i
nc
r
e
a
s
eof f
t
e
r d
e
f
o
r
e
s
t
a
t
i
o
n a
v
a
i
l
a
bl
e P ha
d t
he g
r
e
a
t
e
s
t r
e
d
uc
t
i
o
n, f
o
l
l
o
we
d
i
nt
e
ns
i
t
y. Fo
r a
l
lerosion pat
t
e
r
nsa
Thi
sc
oul
d bea
t
t
r
i
but
e
d t
o pho
s
pho
r
o
us
, a
mmo
ni
a
-
ni
t
r
o
g
e
n a
nd o
r
g
ani
c ma
t
t
e
r
饰 NH4
-
N a
n
dOM . by c
l
a
y i
n t
hes
o
i
l a
nd t
r
a
ns
po
r
t
e
d wi
t
h e
r
ode
d s
e
di
me
nt
s
, whe
r
e
a
s t
o
t
a
l N wa
s
be
i
ng s
t
r
o
ng
l
ybound a
s
s
o
c
i
a
t
e
d wi
t
h OM (
Pe
n
g
, 1
9
9
9
)
.
CONCLUSIONS
I
n t
he ne
wl
y-
de
f
o
r
e
s
t
e
d l
a
nds o
f t
he Loe
s
s Pl
a
t
e
a
u, Chi
na, di
f
f
e
r
e
nc
e
s i
n e
r
o
s
i
on a
nd s
e
di
me
nt
t
r
a
ns
po
r
t pr
oc
e
s
s
e
s i
n s
he
e
t
, r
i
l
l a
nd s
ha
l
l
o
w g
ul
l
y e
r
o
s
i
o
n z
o
ne
s c
a
us
e
d di
f
f
e
r
e
nt i
n
t
e
ns
i
t
i
e
s o
f nut
r
i
e
nt
l
o
s
s
e
s
. Nut
r
i
e
nt c
o
n
t
e
nt pe
r uni
t s
e
di
me
nt de
c
r
e
a
s
e
d f
r
o
m s
he
e
t t
o s
ha
l
l
o
w g
ul
l
y e
r
o
s
i
o
n z
o
ne
s
, whe
r
e
a
s
t
he t
o
t
a
l a
mo
unt o
f nut
r
i
e
nt l
os
s i
nc
r
e
a
s
e
d. A ma
j
o
r
i
t
y o
f nut
r
i
e
nt l
o
s
s
e
s c
a
me f
r
om r
i
l
l a
nd s
ha
l
l
o
w
g
ul
l
y e
r
o
s
i
on z
o
ne
s
, c
o
nt
r
i
but
i
ng a
ppr
o
xi
ma
t
e
l
y 7
0
% of t
he t
ot
a
l nut
r
i
e
nt l
o
s
s i
n hi
l
l
y s
l
o
pe a
r
e
a
s
.
So
i
l nut
r
i
e
nt l
os
s i
nc
r
e
a
s
e
d l
i
ne
a
r
l
y wi
t
h i
nc
r
e
a
s
i
ng s
o
i
l e
r
o
s
i
o
n i
n
t
e
ns
i
t
y. A g
e
ne
r
a
l mode
l f
o
r nut
r
i
e
nt
l
os
s
, NL, a
nd s
o
i
l e
r
o
s
i
o
n i
nt
e
ns
i
t
y
, E,
,
, c
o
ul
d be e
xpr
e
s
s
e
d a
s NL=aEo, whe
r
e a i
s t
he pr
o
po
r
t
i
o
na
l
c
oe
f
f
i
c
i
e
nt
. Ac
c
o
r
di
ng t
o t
he di
f
f
e
r
e
nc
e o
f a v
a
l
ue
s f
r
o
m di
f
f
e
r
e
n
t e
r
o
s
i
o
n do
mi
na
nt z
one
s
, f
ut
ur
e r
e
s
e
a
r
c
h
o
n nut
r
i
e
n
t l
o
s
s s
ho
ul
d be c
o
nduc
t
e
d a
c
c
or
di
ng t
o do
mi
na
nt e
r
o
s
i
o
n z
o
ne
s a
nd e
r
os
i
o
n pa
t
t
e
r
ns o
n t
he
Loe
s
s Pl
a
t
e
a
u. Al
s
o, t
he
r
e we
r
e di
fe
r
e
nt n
ut
r
i
e
nt e
nr
i
c
hme
nt r
a
t
i
o
s f
o
r t
o
t
a
l N, OM, NH4
-
N, a
nd
a
v
a
i
l
a
bl
e P wi
t
h a
v
ai
l
a
bl
e P a
nd NH4
-
N be
i
ng hi
g
he
r
. Addi
t
i
o
na
l
l
y
, s
o
i
l nut
r
i
e
nt l
o
s
s wa
s c
l
o
s
e
l
y r
e
l
a
t
e
d
t
o di
fe
r
e
nt e
r
o
s
i
o
n pa
t
t
e
r
ns
, i
. e
.
, s
he
e
t
, r
i
l
l a
nd s
ha
l
l
o
w g
ul
l
y e
r
o
s
i
o
n. The mo
s
t s
e
v
e
r
e s
o
i
l e
r
o
s
i
o
n a
nd
nut
r
i
e
n
t l
o
s
s
e
s oc
c
ur
r
e
d i
n t
he s
ha
l
l
o
w g
ul
l
y c
hanne
l
s o
n l
o
e
s
s
i
a
l hi
l
l
s
l
o
pe
s a
nd ne
xt i
n r
i
l
l e
r
o
s
i
o
n a
r
e
a
s
I
n t
he s
hal
l
o
w g
ul
l
y c
ha
nne
l s
e
v
e
n y
e
a
r
s af
t
e
r de
f
o
r
e
s
t
a
t
i
o
n, OM, t
o
t
a
l N, NH4
-
N, a
nd a
v
a
i
l
a
bl
e P we
r
e
r
e
du
c
e
d b
y 6
9
%, 4
6.
7
%, 6
5.
6
% a
n
d 8
6
.
6
%, r
e
s
pe
c
t
i
v
e
l
y
.
T
he
s
e r
e
s
e
a
r
c
h indi
f
ng
s wi
l
l he
l
p i
mpr
o
v
e t
he unde
r
s
t
a
ndi
ng o
n e
fe
c
t
s o
f e
r
o
s
i
on pr
oc
e
s
s
e
s o
n s
o
i
l
qua
l
i
t
y de
g
r
a
da
t
i
on, a
nd ma
y pr
o
vi
de r
e
f
e
r
e
nc
e da
t
a f
o
r e
c
o
-
e
n
vi
r
o
nme
n
t
a
l r
e
ha
bi
l
i
t
a
t
i
o
n o
n t
he Loe
s
s
Pl
at
eau of Chi
na.
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a
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h
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o
i
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c
i
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n
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fe
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e
n a
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s
s
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n s
ur
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a
c
e r
un
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2)
: 5
3
5
-5
43
.
万方数据
SOI
L EROSI
ON EFFECT ON SOI
L NUTRI
ENT LOSS
715
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e
a
m Tr
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c
ul
t
ur
al Che
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a
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o
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9
7
6
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9
7
8
)
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r
t No. EAP- 6
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53
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2
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vi
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nme
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ur
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t
i
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9
7
9
-1
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8
0)
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r
t No. EAP- 6
0
0
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53
-
8
4
-
0
5
5
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vi
r
o
nme
n
t
a
l
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e
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t
e
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I
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t
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r Re
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ou
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c
e
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n Chi
n
e
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e
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. S
ha
a
n
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i
e
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al Pr
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Ta
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i
l e
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o
s
i
o
n a
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o
i
l de
g
r
a
da
t
i
o
n o
n t
h
e Lo
e
s
s Pl
a
t
e
a
u.
Bul
l
e
t
i
n o
f So
i
l a
nd Wat
e
r Co
ns
e
r
v
a
t
i
o
n (
i
n Chi
n
e
s
e
)
. 7(
6
)
: 1
8
-2
3
.
Ti
a
n, G. M.
, Wa
n
g, F. E. a
nd Ch
e
n, Y. X. 2
0
0
3
. Efe
c
t o
f di
fe
r
e
n
t v
e
g
e
t
a
t
i
o
n s
ys
t
e
ms on s
oi
l e
r
o
s
i
on a
nd s
o
i
l nu
t
r
i
e
n
t
s
i
n r
e
d s
oi
l r
e
g
i
on o
f Sou
t
h
e
a
s
t
e
r
n Chi
na. Pe
d
o
s
phe
r
e
. 1
3(
2
)
: 1
21
-1
2
8.
Yo
ung, R. A.
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ne
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s
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, Mut
c
hl
e
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nhaue
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al and phys
i
c
al e
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i
c
hme
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s
e
di
me
n
t f
r
om c
r
opl
a
nd. Tr
a
ns
. o
f ASAE. 29(
1
)
: 1
6
5
-1
6
9.
Zha
ng
, Y.
, Pe
ng, B. Z.
, Ga
o, X. a
nd Yang, H. 2
0
0
4. De
g
r
a
da
t
i
o
n of s
o
i
l pr
o
pe
r
t
i
e
s due t
o e
r
o
s
i
o
n o
n s
l
o
pi
n
g l
a
nd i
n
s
ou
t
he
r
n J
i
a
n
g
s
u Pr
o
vi
nc
e
, Chi
na. Pe
d
o
s
phe
r
e
. 14(
1
)
: 1
7
-2
6.
万方数据