**3.2 Chemical properties**

In Exp-1, the soil organic matter content in the agropastoral plots was 1.20 times higher than that in the control plots with significant difference at the reconversion from the pasture. However, in Exp-2, the soil organic matter content in the agropastoral plots was same (1.04 times) as that in the control plots. Under intensive grazing (Exp.2), even if soybean field was converted to the pasture, the accumulation of organic matter was not promoted (Fig. 1). On the other hand, the phosphate concentration in agropastoral plots was 0.28 times than that in the control plots in Exp.-1 and 0.19 times than that in the control plots in Exp.-2 (Tble 2). Under extensive and intensive grazing, the accumulation of phosphate at soil surface was dissolved. After conversion to the pasture, phospate concentration was reduced by half in only two years (Fig. 2). But, phosphate accumulation was promoted in control plots. In addition, pH of soil surface was also increased with dissolution of phspate accumulation, the acidic soil was improved by nutral soil (Fig. 3).


Source: 1 from Shimoda et.al. (2010) and 2 from Shimoda et al. (2011). \*\*:P<0.01. \*\*:P<0.001

Table 2. Comparison of soil chemical properties at soil surface (0-10cm in depth)

Fig. 1. Change in organic matter percentage (%) of Exp.-2 in the soil surface (0-10cm at depth).

Fig. 2. Change in phosphate concentration (mg/kg) of Exp.-2 in the soil surface (0-10cm at depth). A different letter is significantly different.

**2003 2005 2006**

**2003 2005 2006**

Fig. 2. Change in phosphate concentration (mg/kg) of Exp.-2 in the soil surface (0-10cm at

c c

Fig. 1. Change in organic matter percentage (%) of Exp.-2 in the soil surface (0-10cm at depth).

**Agropastoral (pasture)**

b

**Control**

b

b

**Control**

**Agropastoral (pasture)**

a

**2**

**0**

depth). A different letter is significantly different.

**10**

P

h

o

s

p

h

a

t

e

(m

/

k

g)

g

**20**

**30**

**40**

**50**

Org

a

nic

m

a

t

t

er

(%)

**3**

**4**

Fig. 3. Change in pH of Exp.-2 in the soil surface (0-10cm at depth). A different letter is significantly different.

#### **3.3 Physical properties**

In soil samples from deeper than 10 cm, the gaseous phase percentage in the agropastoral plots was significantly higher than in control plots (Fig 4), but was lower at the soil surface (0–10 cm depth). The bulk density of samples from the soil surface of agropastoral plots was higher than that of control plots, and the bulk density of soil samples from deeper than 20 cm was lower than that of control plots (Fig. 4). But, they did not have significantly difference. In addition, the percentage of large aggregates in the soil of the agropastoral plots was 3 to 7% higher than that in control plots at each depth (Fig. 4). Especially, at the soil surface, it was significantly higher than that in control plots.

\*,\*\*:Data are significantly different at 5% and 1% level from the control plot, respectively.

Fig. 4. Physical properties of the soil in agropastoral and control plots of Exp.-1. Gray bar is the mean value and SD in agropastoral plot and white bar is those in control plot.
