OCR Text |
Show TWO KINDS OF SOIL MULCHES Foreign Material, Such as Straw, Leaves, Manure and Sand Applied Ap-plied to the Surface. A mulch is anything applied to the surface of the soil primarily for the purpose' of preventing evaporation, and occasionally to keep down weeds and prevent winter killing of plants, There are two general kinds of mulches: (1) Foreign material, such as straw, leaves, sawdust, manure, stubble and sand applied to the surface; sur-face; (2) Those composed of natural soil modified by tillage. One of this kind is called "dust mulch" or "dust blanket" and is simply a layer of soil which has been loosened up and dried out, explains Professor Freere of the Colorado Agricultural College. Mulches of foreign material play a very small part in general farming, but are extensively used in horticulture horticul-ture in some localities. The principle of the much is as follows: fol-lows: Loose, dry material covering wet soil retards movement of water to the surface, and keeps the dry, circulating cir-culating air from contact with the moist soil, thereby greatly reducing the loss of water. The finer the mulch the looser It must be to give good results. Ordinary Ordi-nary soil mulches two to three inches deep are usually most effective. When a mulch becomes wet its effectiveness ef-fectiveness is gone until it is dried out again. Lieht rains and Irrigations on a mulched soil are worse than no application appli-cation of water, because they only wet and destroy the mulch and allow the water from below to escape, without with-out adding any to replace it. Additional Addi-tional expense is incurred by the cultivation cul-tivation which must b immediately started to restore the mulch. A quantity of water retained by cultivation cul-tivation is of far greater value even where water is plentiful than the same amount applied to the soil. One of the great principles of dry farming is to keep a good rrulch on the soil all the time to prevent loss of water by evaporation. |