104
7 Effects of Conservation Practices …
To assess the work capacity of each conservation practice, the retention abilities
of the structural measures (e.g., check dam farmland and terrace farmland), and those
of the vegetative measures (e.g., forest land and grassland) are also compared and
discussed here. As shown in Table 7.3, the retention abilities of the representative
Table 7.3 Retention abilities of the conservation practices during the treatment period 1954–2004
Land use
Year
Area
(hm 2 )
RA
Water
(m 3 /hm 2 )
Soil
(10 3
kg/hm 2 )
TN
(10 3
kg/hm 2 )
TP
(10 3
kg/hm 2 )
SOM
(10 3
kg/hm 2 )
Dam
farmland
1954–1959
–
–
–
–
–
–
1960–1969
5.3 100 309.43 47 030.19 14.58
60.20
248.79
1970–1979
5.3
95 207.55 56 433.96 17.49
72.24
298.54
1980–1989
10.7
44 088.79 27 274.77
8.46
34.91
144.28
1990–1999
10.7
43 370.09 23 766.36
7.37
30.42
125.72
2000–2004
10.7
49 492.52 26 082.24
8.09
33.39
137.98
1954–2004
8.5
54 195.55 29 008.20
8.99
37.13
153.45
Terrace
farmland
1954–1959
3.2
178.13
31.25
0.01
0.04
0.13
1960–1969
4.6
263.04
39.13
0.01
0.05
0.17
1970–1979
24.6
178.86
30.08
0.01
0.04
0.13
1980–1989
17.2
275.00
43.60
0.01
0.05
0.18
1990–1999
16.9
130.77
21.30
0.01
0.03
0.09
2000–2004
31.1
476.85
67.20
0.02
0.08
0.28
1954–2004
16.3
234.22
36.89
0.01
0.05
0.16
Forest
land
1954–1959 170.4
179.23
24.30
0.01
0.03
0.11
1960–1969 114.7
139.15
19.35
0.01
0.02
0.08
1970–1979 243.9
100.62
15.09
0.00
0.02
0.07
1980–1989 379.8
157.48
21.48
0.01
0.03
0.09
1990–1999 294.4
69.80
10.84
0.00
0.01
0.05
2000–2004 439.8
231.47
31.81
0.01
0.04
0.14
1954–2004 273.8
126.68
17.75
0.00
0.02
0.08
Grassland 1954–1959
52.7
123.15
16.51
0.01
0.03
0.10
1960–1969 116.5
117.00
16.22
0.01
0.03
0.10
1970–1979 117.0
87.18
10.17
0.00
0.02
0.06
1980–1989
62.9
117.65
16.85
0.01
0.03
0.10
1990–1999
50.6
49.41
5.53
0.00
0.01
0.03
2000–2004
78.2
156.52
24.30
0.01
0.05
0.15
1954–2004
79.7
115.51
15.44
0.01
0.03
0.09
Notes No observation data for check dams in 1950s, since the dam farmlands had not been formed
on a relatively large scale at that time
7 Effects of Conservation Practices …
To assess the work capacity of each conservation practice, the retention abilities
of the structural measures (e.g., check dam farmland and terrace farmland), and those
of the vegetative measures (e.g., forest land and grassland) are also compared and
discussed here. As shown in Table 7.3, the retention abilities of the representative
Table 7.3 Retention abilities of the conservation practices during the treatment period 1954–2004
Land use
Year
Area
(hm 2 )
RA
Water
(m 3 /hm 2 )
Soil
(10 3
kg/hm 2 )
TN
(10 3
kg/hm 2 )
TP
(10 3
kg/hm 2 )
SOM
(10 3
kg/hm 2 )
Dam
farmland
1954–1959
–
–
–
–
–
–
1960–1969
5.3 100 309.43 47 030.19 14.58
60.20
248.79
1970–1979
5.3
95 207.55 56 433.96 17.49
72.24
298.54
1980–1989
10.7
44 088.79 27 274.77
8.46
34.91
144.28
1990–1999
10.7
43 370.09 23 766.36
7.37
30.42
125.72
2000–2004
10.7
49 492.52 26 082.24
8.09
33.39
137.98
1954–2004
8.5
54 195.55 29 008.20
8.99
37.13
153.45
Terrace
farmland
1954–1959
3.2
178.13
31.25
0.01
0.04
0.13
1960–1969
4.6
263.04
39.13
0.01
0.05
0.17
1970–1979
24.6
178.86
30.08
0.01
0.04
0.13
1980–1989
17.2
275.00
43.60
0.01
0.05
0.18
1990–1999
16.9
130.77
21.30
0.01
0.03
0.09
2000–2004
31.1
476.85
67.20
0.02
0.08
0.28
1954–2004
16.3
234.22
36.89
0.01
0.05
0.16
Forest
land
1954–1959 170.4
179.23
24.30
0.01
0.03
0.11
1960–1969 114.7
139.15
19.35
0.01
0.02
0.08
1970–1979 243.9
100.62
15.09
0.00
0.02
0.07
1980–1989 379.8
157.48
21.48
0.01
0.03
0.09
1990–1999 294.4
69.80
10.84
0.00
0.01
0.05
2000–2004 439.8
231.47
31.81
0.01
0.04
0.14
1954–2004 273.8
126.68
17.75
0.00
0.02
0.08
Grassland 1954–1959
52.7
123.15
16.51
0.01
0.03
0.10
1960–1969 116.5
117.00
16.22
0.01
0.03
0.10
1970–1979 117.0
87.18
10.17
0.00
0.02
0.06
1980–1989
62.9
117.65
16.85
0.01
0.03
0.10
1990–1999
50.6
49.41
5.53
0.00
0.01
0.03
2000–2004
78.2
156.52
24.30
0.01
0.05
0.15
1954–2004
79.7
115.51
15.44
0.01
0.03
0.09
Notes No observation data for check dams in 1950s, since the dam farmlands had not been formed
on a relatively large scale at that time