/i.n. ''if ' i f L 63d Congress 1st Sesdon SKXAT :•; ( Document ] No. 228 CONSERVATION OF RAINFALL MEMORANDUM ON THE WORK OF COL. FREEMAN THORP ON HIS FARM AT HUBERT. MINN. From the report of Prof. W. J. Spillman to the Secretary of Agriculture ^ PRESENTED BY MR. CLAPP November 3, 1913. — Ordered to be printed WASHINGTON 1913 0. OF D. ^m 2t- 1918 \^ ^ MEMORANDUM ON THE WORK OF COL. FREEMAN THORP ON HIS FARM AT HUBERT, MINN. Oil August 18 and 19. 1913, I had the privilege of examining the farm of Col. Thorp, inchiding his forest plantations, and of study- ing the interesting methods which he has there developed. The most striking originality is apparent in all Col, Thorp's work. He is a man who thinks deeply and rationally on problems which arise in his work, and he lias worked out a number of important problems in connection with farming, especially for his own locality, though some of these problems pertain to wide regions. I will dis- cuss these problems separately and outline the solutions for them which Col. Thorp has found, indicating my opinion as to the general applicability of the methods developed. SOIL. The soil on Col. Thorp's tract is, in the main, a light sand, but interspersed here and there are considerable areas of muck land. EMBANKMENT SYSTEM. Col. Thorp has instituted on the 1,500 acres of land which he owns a simple system of embankments constructed at very small cost, which accomplishes the following purposes : In the first place, it conserves the entire rainfall of the region, causing the water to soak into the soil without run-off. Secondly, it prevents soil erosion. Tn the third place, the prevention of erosion incidently prevents the washing away of soluble salts in the soil. The embankments referred to are not so numerous as to prevent all surface flow of water, but they are so arranged, so far as I could see, over the whole tract as to cause all surface flow to lodge in places where it is beneficial rather than harmful. Col. Thorp's tract may be divided into forests, pastures, and culti- vated fields. The embankment system is found on all three classes of land. The prevention of run-off in his forest tracts appears to have greatly increased the growth of forest trees in those localities where the water is held by the embankments. He has purposely left one tract of forest without embankments, though whatever run-off occurs from it is caught elsewhere. The forest growth in this section of his timbered lands is much less satisfactory than in those sections where the embankments occur. It might be urged that on lands as sandy as those in question there would be practically no run-off even without the embankments. It happened that while I was at this place a considerable rainfall 8 4 CONSERVATION OF RAINFALL. occurred. Water ran freely over sandy soils near Col. Thorp's house. But the system of embankments in that locality led this water into a garden tract, where it was useful. I am of the opinion that in the sandy soils of the North the simple system of easily constructed embankments used by Col. Thorp could easily be made to prevent all run-off. The saving of moisture thus made would be less striking than in some other sections, on account of the sandy nature of the soil, yet the results on this farm show that the system is important even for these sandy soils. In arid and semiarid regions, especially where the soil is not sandy, and where rainfall when it does occur is more or less torrential, I am of opinion that this system would be of even greater value than it is on the sandy soils of northern Minnesota. In what we may call the semihumicl belt lying betAveen the humid regions of the East and the semiarid regions' of "the West the embankment system would doubtless be of great value and would insure crops in many years where there Avould otherwise be failure. In this connection I would call your attention to the inclosed extract from the Kansas Farmer of July 10. by Prof. Edwai'd C. Johnson, giving an account of a very similar embankment system in use in certain portions of the State of Kansas. Prof. Johnson gives it credit for marked effect on crop yields. ("oNTOuu Farming in Kansas. By Edward C. .Iohnson. K. S. A. C [Extract from Kansas Farmer, July 19, 1913. Copyright, 191.3.] Coutour farming is the luuiie given to ii system of farming on rolling lands which are contonreil in more or less mulnlnting ridges around the slopes in order to prevent excessive run-off and soil \YaslHng after torrential rains. It has been used for many years on the sandy, rolling lands of Alabama. Georgia, and the Carolinas, where soil wasliing is very troublesome. ;!nd is now being used in the best young orchards of Maryland and the Virginias. Until late years, however, contour farming was unknown in Kansas. Adaptations of this system' are now in use in this State in the northeast sec- tion to prevent soil wasliing and in western Kansas to catch and liold water. In Leavenworth County Mr. ,T. M. Gilman. famous corn man and experimenter, has couuneuced to work his rolling tields on a contour plan. AYith an im- provised level consisting of a 2 by 4, 14 feet long, and a carpenter's level, he has laid off base lines in his fields with a slope of 1* inches to every 14 feet. These b-ase lines are run at such a distance apart that the average drop from one to the other is (> feet. This leaves the lines .30 to 60 feet apart. In plow- ing these lands IMr. Gilman throws the back furrows on the base lines and the dead furrows come midway between, thus ridging the land slightly. The same system of plowing will be followed from year to year until the fields are shaped into gently rolling contours or terraces, which will carry any excess of water and will prevent washing after the heaviest rains. Even this year, when the land has been plowed only once on this plan, soil washing has been effectively prevented. As the ridges are not abrupt but gently rolling, crops are planted on the land and handled without regard to the ridges. In western Kansas, on the farm of F. J. and D. J. Rundle. Almena, Norton County, a still more interesting modification of contour farming is found. Here a system of contouring has been used for four years, not so much to prevent soil washing as to prevent useless waste of water by excessive run-off. In this region moisture is usually the limiting factor in crop production, and if every drop can be saved much is gained. Four years ago. therefore, the Rundle brothers devised a contour system to prevent waste of water. With the aid of a farm level, similar to a surveyor's level but much less expensive, they laid out base lines around the slopes on their rolling fields, 50 to 100 feet apart, CONSEEVATION OF EAINPALL. 5 giving no slope to tliem wliatever. In planting corn or sorgliunis tliey start the lister on a base line, listing parallel to this line until half the laud is listed- The lister is then started on the next base line and eoutinned on both sides of it and parallel to it nntil the listed furrows meet the listed portion next to tiie lireceding base line. Any small irreguhir strips which may remain are then listed in short furrows parallel to one listed side or the other. When these are huished listing is started on the next base line, etc., until the field is planted. Now, when the rains come iu torrents, as is often the case in western Kansas, the water is caught in the furrows, which often are filled from rim to rim, so that clear belts of water may be seen stretching around the slopes. After ordinary showers there is no run-off whatever, while after a torrential rain the run-off is reduced to a minimum and the water soaks into the ground instead of being wasted uselessly. The additional moisture thus utilized often is sufhcient to insure successful crops, where if run-off were allowed failure would result. The Kundle brothers have had successful crops in seasons when their neighbors, farming according to the usual methods, have had little or nothing. This system is ;ilso used when oats and wheat are grown, the land being ridged slightly along the base lines by an improvised grader or drag, made of planking, or by [)lowing bacli furrows along the base lines, lea\ing dead fur- rows midway between. Contour farming could undoubtedly be utilized profitably in this State to a much greater extent than at present. In the northeast section there is much rolling laud which is not cut up too badly to contour easily. Here contouring to ])revent soil washing would be found practicable in many cases not only where general farnnig is carried on but also where young orchards are being [ilanted. In western Kansas rolling lands or lands sloping slightly are also exceed- ingly plentiful. Here, where every drop of water that comes should be saved and utilized to the utmost, contour farming will be a wonderful help in water conservation. In humid and siiperhuniid re^-iun^s it is dotibtfiil if Col. Thorp's system could be utilized without modification, on accoiyit of the excessive amount of moisture it would hold on the soil in nianv places. But by a very slight modification, such as is seen in the Mangum terrace described in Bureau of Plant Industry Circular K-i. the system would add greatly to the proportion of the rainfall absorbed by the soil and at the same time dispose of the stu'plus which would be injurious rather than l)eneficial if held en the soil. o- I