Soil Quality

SOIL QUALITY

There is a reasonable relationship between soil organic carbon (soil organic matter = 1.7 * soil organic C) and relative cotton yields (see figure). One can walk across the plots and see and feel the differences in soil quality from one plot to the next. For example, estimates of long term soil erosion demonstrate some of the effects of treatment and tillage on soil erosion potential.

Estimate of annual soil loss (tons/acre) using RUSLE2. Tolerance (“T”) for this soil is 5.0 tons/acre/year.

Old Rotation treatment

Conventional tillage

1896-1997

No-till/conservation tillage

1997-present

Continuous cotton with fertilizer N only (plot 13)

8.0

5.1

Continuous cotton with winter legume cover crop (plots 2, 3 & 8)

6.1

3.3

The long-term differences in soil quality/soil health in The Old Rotation has been the impetus behind the development of the A.U. Soil Quality Index for the A.U. Soil Testing Lab.