Show conservation notes by W V kail TO show the need tor for application 0 of conservation practices in other commercial com merial fields 1 highway magazine tor for february carried quite an all interesting article more less related to conservation entitled grass protects airport surfaces it was brought out that paved runways t taxiways a x 1 w a y s and aprons of commercial and other airports seldom constitute more than 12 to 16 per cent of the airfields surface thus some 85 per cent of the area of many fields and the entire surface of others 0 used primarily tor for private flying have other than hard surfaces such surfaces are economically provided in most cases by sod or other types of vegetative cover there are innumerable grasses and other types of vegetation useful in stabilizing the surface 1 of tha the soil to prevent dust mud drifting sand and erosion it was emphasized that topsoil and natural ground cover should be conserved wherever possible during construction of an airport however where it Is necessary to stockpile or borrow topsoil top soll it sometimes is more economical ono mical to build up a sufficiently good soil from the subsoil by use of fertilizers also an important note Is tho the jiral drainage naga of the area on oil which grass Is to be grown A well drained soil encourages the growth of 0 healthy drought re distant vegetative cover A well developed sod will absorb a relatively high per cent of surface water and still retain a wear re distant surface surf aca experiments have shown with the rain making machine that a good grass cover absorbs ten times as much water as a thin sod thus surface runoff factors tor for design of 0 drainage systems are considerably affected by the type and density of cover that can be established on an airport soon after construction is completed it further states that it should be emphasized that rapid runoff with consequent conie conee quent erosion and Is not con confined cont ineil tined to regions of relatively higher rainfall flash storms in arid and semiarid arad regions may cause serious washing ln in a relatively short time and small gullies in fresh tills fills may develop rapidly into deep channels paved gutters and waterways aier ways are necessary ansome on some slopes ad abent to airfields but ins been found to be a diore mora so e ono mical expedient under most conditions |