On an epicalcareous epipedal Black Vertosol, the physical characteristics of the soil under two different management practices were measured and compared with each other. Located next to each other various physical properties of a cultivated area were compared to those in a pasture area. Were the readings from both areas accurate, and how do the two sites compare with each other. What are the agricultural and environmental implications?

Some of the readings between the two sites such as sorptivity, and steady state rate illustrate the differences between the two sites. For sorptivity (the ability of a soil to initially absorb water), when an average of the readings for ponded disc, and tension disc is taken the sorptivity for pasture is 0.695mm/hr, and the cultivated area is 0.336mm/hr. The pasture having the higher reading would be expected as the redeveloped soil structure would have macropores, roots and even large cracks that allow water faster initial entry. Once the steady state rate was reached an average of the readings of the ponded disc, and the tension disc was 0.395 for the pasture, and 0.155 mm/hr for the cultivated area. Several contributing factors could be involved here. Certainly the establishment of pathways through the soil by roots, microflora, and seasonal expansion and contraction over time in an undisturbed soil would accumulate there by increasing the steady state rate. But also other factors like the build up of organic carbon through the profile causing a decrease in the bulk density of the soil. Bulk density can be a factor in decreasing the steady state rate.

The implications of these results agriculturally and environmentally can be measured by how long the two areas can remain productive under their present management regimes. Both areas have been treated as a pasture site and a cultivated site for 40 years. The main factors determining a lot of the physical characteristics of the soil are the soil texture and soil structure. The texture will remain constant; therefore the main factor that has been altered between the two sites is the soil structure.

The soil of the pasture site having not been cultivated or disturbed since the pasture was established acts as a perfect comparison to the cultivated site. Both sites are of the same age, and the cultivated site has been under continuous cultivation for as long as the pasture has been established. An area once cleared then left as a pasture, is allowed to reestablish its soil structure. Measuring the physical characteristics of each site and comparing them, allows us to see what characteristics the continued cultivation really affects. Agriculturally if the yields obtained from crops grown on the cultivated areas started to decline a comparison of the physical measurements between the two would allow us to determine if the decline was due to changes in the physical properties. From an environmental perspective if the type of management imposed on the land contributed to the destruction of the soil profile, or contributed to any land degradation else where, it would have to be modified to stop this from happening. At the moment there is no indication of this

When comparing areas under cultivation and pasture on the same soil from the perspective of physical characteristics, the soil structure is of particular interest. For it’s the soil structure and how developed it is that will greatly influence many important physical properties of the soil. To really see how significant the differences of each characteristic being measured are, the measurement being taken needs to be replicated many times over both areas. Only when this is done do we really know how each management practice really effects the physical characteristics of the soil.