PHYSICAL PROPERTIES OF SOILS UNDER SUB-SURFACE DRAINAGE SYSTEM

The suitability of soil for crop production may be determined by its physical properties. These properties, for example, affect crop production through nutrients supply, water infiltration, and water holding capacity. In addition, they play an important role in influencing the behavior of plant growth. Keeping in view the significance of soil physical environment in relation to plant growth, this study was designed to determine and evaluate the physical properties of soils at various depths located in the Mardan SCARP area of Khyber Pakhtunkhwa Province (Pakistan) during 2003-04. The analysis of variance indicated non-significant changes in sand, silt and clay fractions with cropping sequence, but showed significant changes in sand and clay with soil depth. Sand particles decreased while clay increased with increasing soil depth. Soil permeability, leaching fraction and hydraulic conductivity, on the other hand, showed significant changes with cropping sequence and depth. Soil permeability and leaching fraction, for example, were greatest after maize than after or before wheat and both fractions increased with increasing depth. These results suggested that soil physical properties changed with increasing depth. Although cropping did not significantly influence the particle size distribution, it exerted significant influence on soil permeability, leaching fraction and hydraulic conductivity. It is important to note that this study will be useful to devise soil management practices for the Mardan SCARP area.