SoilE 



rosion 



By John E. Nelson, E. C. W. Engineer 



A(;l..\N< K ;U lli<- Mill t■^ll^l imi 

 of mill. lis will (liscliiM- thiU Mil. -I 

 of th<' erosion lies aloim tilt- Mi> 

 -i^-^ippi anil lllini>js riser-. Tlii- i> |i;irtl\ 

 • Imp ti' the fart that iiiosi of tliis nw.t i~ 

 loTliiii;- or llilly. Iml otln-r- liillv ansis in 

 the State arc not Milijed to niucli (•ro--i..ii. 

 Wliy doc- this conditioM exist ',' 



I.i-I lis liMii l.ai k a fiv. niiilioii \i-ai- 

 for the aiisuer. Tlie la>l ire -lieel i- re 

 ii'dinK fioiii the (ircat l.alie- iet;ion an I 

 rivers ai'e larryin^; a fidl load of filaeial 

 silt. Much of this is de|iositeil in mud 

 l>ar,ks. which dry and are blown eastward 

 as dust, hy the prexailinjr west winds. 

 By the time a timher trrowth lia-- he- 

 come larpe enounh to ludil most of the 

 soil in place, a hlankel of this "Iocs-" 

 <evers most of what is later to become 

 Illinois. This hlankef varies in thicknes^^ 

 from tliirt.\- feet near the Mississippi, to 

 « mere trace as far east as Champaign. 

 .Another lonjr period of time elapses dur- 

 ing whicii topsoil is jiradually huilt up by 

 vcKPtation. Then the white man invade.-, 

 clears off the timber, and plows up the 

 'od. Rains bpcin to wash the loosened 

 l<ipsoil from the hills. This continues, 

 until today thp loess is ajrain near the 

 surface, and iw man.v spnts is actually 

 exposed. 



The process of siiiface washing is 

 known as sheet erosion, and while not so 

 apparent as gull.v erosion, is much more 

 detrimental. University of Illinois Ccd- 

 Uge of Agriculture figures show that on 

 rolling farm lands, the fertility lost 

 through sheet erosion is 21 times that 

 used by crops. Too iiiui-h stress cannot 

 be laid on the fact that erosion is occur- 

 ring on all farmed land with a slope 

 greater than ;!*;. even though iio gullies 

 are visible. .\side from reforestation 

 Ibera are two general niethoils of check 

 ing slieet erosion. One is Viy seeding 

 down, strip cropping', or contour farni- 

 ing. The other is a mechanical means 

 of preventing erosion, known as terrac- 

 ing. Terraces have been used for nearly 

 fifty years in the Carolinas. Kentucky, 

 and Virginia, .^t first they were nifrely 

 ridges thrown up across the face of the 

 hillside to check the runoff during rains, 

 firadually they were improved, however, 

 imtil today terraces aie Viuilt to meet the 

 particidar soil, slope, and iropping rc- 

 Tiirements of any localit.x . 



The terrace re<-ommcn<led by the state 

 Tniversity is a shallow channel 2.5 to "d 

 feet wide, and from I.t to 20 inches deep. 

 Its slope is about 4 inches in 100 feet, 

 .iust enough so that the water will slow- 

 ly flow toward the e<ige of the field and 



r,ui.r.y dam bui 



a y ii.»<.<.i! !• 



i^oi Ipi-.ak ..ici tlu' (.!■ 



race. The vertical di- 



lance between sueces 



-ive teriace- -hould lie 



from ibrei- to -i\ feel. 



riiiis. III! a r. -Uipe 



the lerraies would be 



about KllP feet apart. 



.An ade(|uafe outlet i- 



veiy important since al! 



of the water from tin 



(i<dd is c<>n<ent lated at 



the lower ends of the 



terraces. For this purpose a permaiient 



channel with check structures below each 



terrace is reconimei;de<l. 



In Illinois, btjoad base !errace< are be 

 ing Used on only ab<.ut IC.OttO acres of 

 farm land. In view of the fact that more 

 than 12 million a<-res of Illinois land are 

 -idiject to sheet and gully erosion, it i< 

 apparent that further interest in terrac- 

 ing is necessary. Within the past few- 

 years the moisture con.servation value of 

 terraces has been realized. In a dry year 

 the Cidlege of .Agriculture has obtained 

 i"i bushels more corn per acre on a 

 terraced slope than on it similar slope 

 which ha<l no terraces. Thus, the i<l<a 

 that terraies are particularly beneficial 

 during a rainy season, is supplenient<'il 

 by the fait that during dry years a ter- 

 race acts as a moisture saver. 



This next sjiring the Illinois Kmer- 

 gencv ronservation Work program will 

 undertake a cooperative terracing inoi- 

 ect with the farm owners of Illinois. ,^u<li 

 [dans have been in operation on a large 

 -tale in Te\a-. K.-insas. Oklahonia. and 

 other slates for a year or more. There 

 ;ire 11' ('('(' camp- ::< ihi- .'^late whicli 

 are doing soil erosion w.irk on farm 

 lands. In the past ('('<' labor has Iwei; 

 .ivailable oidy for gully control wi.rk in 

 Illinois. Since sheet ero-ion i-^ -<• pieva- 

 lent and t<-riaring -o neces-ary. how- 

 ever, these 19 camps, if authorized for 

 continuation by Congress, will aid in ter- 

 racing farm lands as well as doing gully 

 work. The plan will be for the farnur 

 to construct the terraces according to a 

 survey made liy an K. C. W. engineer. 

 CCC labor will then be used to build the 

 necessary permanent outlet structures for 

 each terrace system. For a limited time. 

 K. C. \V, funds Vill be used to nurcha-^e 

 material for the.-e structures. 



In order to facilitate the terrace build 

 ing. "terracing clubs" are being formed 

 by the farm owners in the counties whicli 

 are to have the benefit of CCC labi.r foi 

 this work. The object of these clubs is 

 to purchase or rent machinery for huild- 



i: BY IHK CIVIIIAV COSSIKVATIOV roKTf 



l.!y I:.,,,., 



ing terrace-. .\ terra< ing graiier and a 

 caterpillar tractor are liest for this Avork 

 Thus, a far in owner wisl^ing to terrace a 

 field « ill -igii an agreeiiieiit with his 

 local teriacii:!.' club to have the work 

 done. He will then -ign a cooperative 

 a'.'iecMient with the .'^tate to have th< 

 . litlel structures liuilt by «'«'C laivor. H;s 

 only fcxpiiise will be ci'st of operating 

 the terracing equipment. Figures from 

 other states -how that this will vnry 

 from ?I..'0 to 52..'>(i an acre. Thi.s figure 

 inidudes retiring the cost of new equip 

 niei.t or rental charges for rented eqii.p 

 •lei.t. Incidentally, the cost to the St«T» 

 f..r material^ for the .concrete check 

 -tru< tiires in the outlet channel will rarj 

 fr..m ST. 00 lo $10.00. exclusive of lahor 

 t'crtainly ii.. Illinois fiirmer can afford 

 to lose this opportunity for expert advirt 

 and K. C. W. :iU\ in terracing his rollinir 

 land. 



First Prize Essay 



( I ontii'.ued from page 21 1 

 love- cue another and who has learned 

 cooperatif.il through the home and 

 through ih(-e organizations that support 

 the hojiic. cannot help but live happily 

 and .-iic<-e--fully, 



Karl Brandt writing in Social Research 

 for February declare*: "Inventors, engi- 

 neers, chemists, biologists, physicists, are 

 •training their brains to substitute indus- 

 trial products for farm products. Lard 

 tallow, and rapeseed oil have been re- 

 placed i>y mineral oil as fu^l for lamps: 

 wood arid peat have been replaced by 

 coal, leather and hides by rubber. But 

 there are new and more far-reaching at- 

 tacks pending, .'sulphitspirit. rayon and 

 woodsugar are examples. Sulphitspirit 

 replaces alcohol which i.- distilled from 

 potatoe- or grain, layoii replaces .silk, 

 and woodsugar is converted cellulose to 

 be used instead of feed grain or other 

 carbohydrates for hogs or nnv other ani- 

 mal- 'o be fattened. 



M'RII , 19.1.T 



25 



