Benefits of SOM in Agroecosystems: The Case of China - Soil Carbon: Science, Management and Policy for Multiple Benefits - page 318

(a)

2.5

2.0

1.5

1.0

0.5

0.0

-0.5

(b)

0.4

0.3

0.2

0.1

0.0

-0.1

- 5 0 5 10 15 20 25

Relative change in crop yield (%)

Fig. 27.1. A coupling of soil organic carbon content change with crop yield change under conservation
tillage experiments of China (a, rice paddies; b, dry croplands) (Wang et al ., 2009).

Table 27.2. Crop yield variability over years, from different experiment sites with various SOM levels.
(Courtesy of Dr Xu Mingang for the yield and SOC data from the long-term experiments sites between
the late 1980s and early 2000s.)

Yield variability (%) under
different treatments

Topsoil SOM
(g C kg -1 )

Min Max

Agro/ecoregion Cropping system

Tai Lake Plain Rice 8 30 18.0

Northern Zhejiang Plain Rice 12 30 16.0

Purple basin of Sichuan Summer rice 13 20 16.0

Rolling area of red soils, Jiangxi Double rice 8 17 16.5

Central China Plain Wheat-maize 30 45 7. 5

Rolling area of red soils, Hunan Winter wheat 30 40 10.0

Purple basin of Sichuan Winter wheat 15 30 16.0