Cropping Systems: Applications, Management and Impact

Long-Term Winter Wheat Cropping Influence on Soil Quality ... 69

Figure 2. Regression of bulk density (g cm-3) and soil organic matter (%) in 0-30cm
soil depth after winter wheat.

Soil Chemical Properties

Soil chemical analyses of the investigated winter wheat plots indicate that
SOC, pH, and available P had undergone considerable changes, whereas
available K and CaCO 3 altered less over the observed period. (Table 2). Soil
pH (KCl) values under investigated cropping systems increased, while the
content of available P was cut in half. The fertilized cropping system differed
significantly in contents of the available P and K as a result of the crops in
rotation. After 65-year of the experimental running 2-year rotation showed no
difference in P and K content compared with the 3-year rotation. In the
fertilized plots, the addition of N fertilizers containing ammonium likely
resulted in nitrification and H+ release (Brady and Wail, 2002), but soil pH
tended to increase. The increase in pH from 1970/80 to 2000/07 was
unexpected and contrary to an assumingly normal decrease over time. This
may be due to the effects of a deepening of plow-layer when powerful tractors
(>150 hp) were introduced for plowing in the experimental field. Accordingly,
higher soil pH was measured in the unfertilized treatment and higher content
of Ca2+ was found in the 0-30cm layer, as redistribution of Ca from the >30
cm to the plow-layer slowly changed pH reaction. Similar findings were
reported in the Northern Great Plane (Malo et al., 2005). Thompson and

y = - 4 .1737x + 8. 4907

r = 0.69**(p=0.001)

1.5

2

2.5

3

3.5

4

1.1 1.2 1.3 1.4 1.5 1.6

Soil organic matter (%)

Bulk density (g cm-^3 )