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Show fGROHONY Edited by Prof. J. C. Hogenson. A, C. U. IMPROVEMENT OF ALKALI SOILS. , '' By R. C. Doncghue, Assistant Agronomist, Agro-nomist, Agricultural College, "" North Dakota. Ali soils arc composed of two distinct dis-tinct classes of substances, weathered rock and animal and vegetable matter at various stages of decay. Rocks arc made up of minerals and minerals consist of various compounds of the different chemical elements, some of which' arc of value as plant food and others .that arc not. While these compounds com-pounds arc in the rock form they arc insoluble, but as the process of weathering goes on the various minerals min-erals arc broken down; and the compounds com-pounds arc readily dissolved in the soil water. Where there is abundant rainfall and the texture of the soil and subsoil sub-soil Is of a nature favorable to the process of 'leaching the soluble-compounds arc dissolved out of thc$rc spective soil layers,- and carried by under ground streams, which emerge as springs, to the larger water courses which finally find their, way. to . the sea. If the land is growing a crop, it takes as much of the necessary elements ele-ments as it needs, and leaves those for which it has no use to be carried away in the manner mentioned above. It often occurs that even a part of the essential plant food Is also lost by this leaching process, the result being that the crop yield is proportionately reduced. In regions of light rainfall conditions condi-tions arc different As the process of weathering goes on the rock par tides arc .broken down and soluble compounds known as salts arc form cd. When there is any rain, the water soaks into the dry soil a short ' distance, dissolving these salts from the various soil layers. As soon as the sun comes out the surface begins to dry out, and the water that has J ' just soaked in rises to moisten the r dricdout. layer. This goes on until all of the water that has fallen as'rain t has evaporated. -But what has become be-come of the salts that were dissolved in this water? They remained in so- Iution until the water reached the surface of the soil, and there the water evaporated, leaving the salts upon the surface. - After this process has gone 'on for some time a layer of salts, possibly an inch in thickness will be formed. This layer of salts is termed "alkali" and a soil in this condition is called an "alkali soil." Many. of vthc alkali soils of North Dakota have been formed in a man-ncr man-ncr similar to that dscribcd above with some modifications. They arc found in low places into which the larger part of the field and possibly s'otne other fields drain. The only means of escape' the wa.tcr has from U these "potholes,"- as tlicy arc called, I is by ovapocationt It will be seen 1 that when this water evaporates it i will leave the salts or, "alkali" which 1 have been dissolved frprn the surrounding sur-rounding soil; accumulated in 'one place. After this iias gone on for several years, so- much alkali has ac- cumulated that some of the farm cro;s will not grow. Plants vary considcrablyJ'nrPlioir abilUy Jo grow in the presence of alkali. Ev'cn diff- crent varieties of the same plant may vary and also the same variety at -Jk difC rciit,' stages of if growth. Bar- I ley, sugar beats Qrghum, at; I alfnlf.i I t arc some of.1th$"mo' ;iflQT' nt re- 1 sijtnnt crops. Wheat and corn are I omo-of the plants that jiro "taorr sensitive and arc more likpjgr to . b ' injured by an excess of alkali. It often occurs that thejre is a large percentage of the salts that cause alkali in the subsoil, but not enough in the surface layers to seriously ser-iously affect the crop. In a "case of this kind in the humid region, when we have a dry period the subsoil J water rises by capillarity and -carries some of the salts in solution depositing deposit-ing them on the surface. The same i ,ft thing may occur when irrigation is practiced and too much water is used j without proper cultivation. This is i ' spoken of as the "rising of the alka- li" and care should be taken to prevent pre-vent it if possible. The amount of soluble salt or alkali al-kali which will be injurious to the (plant depends upon .the kind. Such substances as sulphate of soda (glaubcr salts) arc not as harmful as others, such as 'carbonate of soda (salsoda). Sulphate of soda and similar sim-ilar compounds form "white alkali" ' and carbonate of soda and allied :om- j pounds form "black alkali." Ordinar- t ily plants will grow in soils contain ing ten times as much sulphate of soda as they will in. the case of the carbonate. For this reason it is quite important to know the kind of salts which cause an alkali soil before deciding de-ciding on the method for improvement. improve-ment. In most cases "black alkali" can be changed to the sulphate form by the use of gypsum on the land. In most localities the first step in the improvement of alkali soils should be to provide proper drajnagc. Good surface drainage will accomplish this in many cases, but where it can be v done, under drainage is more satis factory. The next step is to grow sbmc green manuring crop such as millet or field peas and plow it un- I der. Plowing under stable manure also has a beneficial effect. If there is only a small amount, grow some ' cultivated crop in order to keep a L, mulch on the surface to prevent cx-tt cx-tt cesstve evaporation. |