The Effect of Wind Blown Road Dust on Soil Reaction and Composition

These studies were designed to show the difficulty in securing a representative soil sample near roads that are or have previously been calcareous and dusty; as well as the effect of road dust on soil reaction and composition. The following statement is found in The Official Methods Outlined for Agricultural Chemists (3rd. Ed. p. 1.), "In view of the variability in soils, it seems impossible at the present time to devise an entirely satisfactory method for sampling." If we acquaint ourselves, however, with some of these problems, it will aid in solving our problem. The deposition of road dust having a different composition than that of the adjacent field soil is a cause for great variation. Observations show that legume and other vegetation differs near dusty, well-traveled, calcareous roads from that farther out in the field. Due to these observations, preliminary tests were made on two samples; one taken 50 feet and another 300 feet east of a limestone road. The results are tabulated in Table 1. Because of the variations in composition of these two samples, and since Indiana alone has over 44,000 miles of limestone and calcareous gravel roads and three-fourths of the soils arc naturaJy a.ld, it was thought that some further study should be given this subject. Samples were taken in quadruplicate, 30 feet apart, from apparently uniform, naturally acid soil of various types at 50 feet, 100 feet, 200 feet, 300 feet, and 400 feet away from either poorly or well-traveled roads which are, or have been, calcareous and dusty. Acidity iand phosphorus tests were made in the laboratory on all samples. Acidity determinations were made according to the LaMotte-Morgan Colormetric pH