Effects of traffic on soil aeration, bulk density and growth of spring barley

This paper reports the results of field experiments on several different soils to quantify the effects of different numbers of passes of vehicular traffic on soil aeration status (measured in terms of oxygen diffusion rate, ODR and redox potential, Eh), soil bulk density and development of spring barley. In a further series of field experiments, the effects of single and dual wheels were compared and the effectiveness of a soil loosener operating behind the wheels was evaluated. Additionally, some microplot experiments are reported in which a range of known values of soil bulk density were produced and the effects on soil aeration and development of spring barley were evaluated. It is shown that repeated wheeling, even by a tractor of only about 2 tonnes weight, can produce soil conditions in which aeration can be limiting for crop growth. The use of dual wheels resulted in lower values of soil bulk density and associated greater soil aeration. The loosener alleviated the compaction produced by wheels and also improved soil aeration. For a sandy loam soil, greatest root growth and crop yield occurred at a bulk density of 1.43 Mg m−3. Soil aeration as a component of soil physical quality is discussed.