Show f. f tL TERRACES WilLI WILL I r AVERT ALERT EROSION nO Most Effective e Method M Can Be ri k Employed to Prevent Washing Washing Wash Wash- i ing of Soil BENCH TERRACE IS ANCIENT r. r By Ridge Plan It tt IB la Possible to Eliminate Elim Elim- i mate Steep Uncultivated Strips That Interfere With FarmIng Farming Farm Farm- Ing Operations K Prepared by the United States Department Depart Depart- Fri ment of or Agriculture r- r T Terracing Is the most effective meth meth- method t. t od of preventing erosion There ere are two distinct types of terraces the terraces the bench terrace and the ridge terrace A field of bench terraces resembles n II L. L t. t selles of benches or a flight of steps step Ridge terraces as the name Implies s I are are simply ridges of earth thrown up r across the slopes of hillsides r Of the two types the bench terrace Is much ranch the older The ridge terrace has come Into general use only during the last 25 years Bench terraces for agricultural purposes were used by bythe bythe the the ancients ancient of Europe Asia and South America The ancient Peruvians In I South America terraced the steep slopes of mountains the walls of the terrace embankments being built 01 of stone y Bench Terrace The b bench terrace Is essentially n a 7 i if steep land steep land terrace RIdge terraces uee are 1 1 much superior for lands of ot moderate slopes as liS with them It Is s possible to toI toJ j. j I I u I t tt t i i wr f J Yr A r r J i r. r y r J. J P r YN W 5 Method of Carrying Terrace Water Under Un Un- 5 der der a Roadway by Means of a Culvert Cul Cul- vert verL vertI i is I s eliminate the steep uncultivated i j strips that Interfere with farming op op- and often are seed beds for j we weeds dg j f The bench terrace Is usually built I with the reversible hillside plow by I I which the soil soli is always thrown down the bill hili This Is done for a number e of years until the bench becomes level Jevel I or the slope of the bench Is slightly I a reversed A ridge of ot earth Is kept at atthe i th the outer edge of the bench to prevent the surface water from running from frIm i 1 one bench to the next bench below helow Bench terraces should bp- bp level be-level that is Js they should have no fall along the i direction of their length Before the bench hench between the terrace embank embank- ments ment Is made level by plowing the I t soil down the slope the surface waiter watter wa wa- iter her is held above the shoulder at nt 5 the outer side of the bench Purt Part Part-of of the water y ry c y move off slowly to the i semis ends of the terrace and the rest will sink Into the soil soli or evaporate jA tA A heavy vy sod should be kept on the shoulder and embankment to prevent should the shoulder be overtopped overtopped over- over topped due to heavy rain fain l When a bench terrace Is first started start ed pd edthe the shoulder should be built about one ione foot high and three feet wide vide at atthe the ithe base These dimensions can be reduced re re- reduced some as ns the leveling d down wn of the bench hench proceeds When the bench hench has hns become level It Is only necessary to toa I Ir r a maintain a t small shoulder about one- one half halt foot toot high at outer side of or the th bench This will prevent possible damage to the terrace due to an excessively excessively heavy rain The distance between the terraces 1 Is governed by the vertical distance o or drop and not by the distance along th the surface of the ground The distance along the Ule surface of the ground willbe wll will be different for different slopes of th the theland theland land where the same vertical distance between the terraces Is used The proper drop or vertical vertical- distance between bench terraces depends largely large large- ly on how much care and attention I Is given to the terraces the greater th thE drop the more care required Th The greater the drop the higher will be th the embankment and It Is much more cult to maintain a high than a low em em- The best practice Ind Indicates Indi- Indi cates eates that the drop between bench terraces terraces ter ter- races should never be less than three thre feet nor more than six feet although n a drop of eight feet teet has hns been use used successfully on steep slopes where th the terraces are carefully maintained |