1942 



MACHINERY 



MACHINERY 



Tillage machinery. 



Soil-tillage may be briefly defined as the art of pre- 

 paring the land for the seeding and growth of a crop and 

 of maintaining the necessary conditions until the crop 

 has matured. The entire process of tillage for a cer- 

 tain crop consists of several more or less related but 

 nevertheless distinct operations. The agricultural tools 



2246. A former European type of plow, still used in improved forms. 



2245. An early Yankee plow, made of wood and the moldboard 

 protected by iron nailed on. (After Roberts) 



and machines which are especially adapted for the 

 different tillage operations, and used rn them are 

 known as tillage machinery. 



Purpose of tillage. 



The different tillage operations form a chain, each 

 link of which is necessary because it accomplishes one 

 or more of the objects of tillage. The chief of these as 

 stated in other works may be enumerated as follows: 



1. To produce a deep, thorough, and uniform granu- 

 lation, giving a well- 

 marked crumb struc- 

 ture. 



2. To regulate soil- 

 ventilation, moisture- 

 content, and tem- 

 perature. 



3. To destroy and 

 prevent the growth of 

 weeds and other un- 

 desirable vegetation. 



4. To effect the deep and thorough incorporation of 

 organic matter. 



5. To make available the maximum amount of plant- 

 food required by the particular crop. 



In short, the object of tillage is to make the soil 

 physically and chemically fit for crop-growth. Tillage 

 is in itself a mechanical operation, producing at first 

 only physical effects on the soil as shown above by the 

 first four objects. The proper combination of these 

 objects, however, results in the chemical transforma- 

 tion of certain soil compounds and the setting free of a 

 certain amount of plant-food elements for direct assimi- 

 lation by the crop. Proper tillage is, therefore, of the 

 utmost importance in crop-growing, as it has to do with 

 both the housing and nourishing of the crop. 



Different tillage operations. 



Tillage operations may be divided into two types or 

 classes according to depth, as (1) plowing or 

 breaking and (2) surface or comparatively shal- 

 low cultivation. 



The first type of tillage may be applied to the 

 breaking of virgin sod, the plowing under of stubble, or 

 merely the plowing of land often plowed before. Plow- 

 ing, however, may be considered as the basic operation 

 of tillage. It is the first and most extensive step in the 

 preparation of the soil for the crop and on its depth 

 depends largely the extent of the physical and chemical 

 perfection of the soil with reference to the crop. Fur- 

 thermore, the success of the second type of tillage 



operations depends largely on the first type and, in 

 fact, from the standpoint of economical and efficient 

 soil management, the second type of operations is of 

 relatively little use without being preceded by the first 

 type. Although the second type of operations may be 

 repeated a number of times until the proper depth of 

 effective tillage is reached, it has been demonstrated 

 in this country, and in Europe particularly, that such a 

 method of procedure is usually impracticable. 



Max Ringelmann, of the Institute Nationale Agro- 

 nomique, Paris, distinguishes between the two types of 

 tillage operations by calling the first type real-tillage 

 and the second type pseudo-tillage. According to this 

 classification, real-tillage consists in cutting, inverting 

 and partially pulverizing the soil by plowing. The 

 tough sod of the virgin prairie is turned over in a more 

 or less compact slice and much of the dense poorly 

 aerated texture remains. This necessitates the intensi- 

 fying of the pseudo-tillage operations until the virgin 

 soil is reduced to the well-aerated, loose, crumbly, and 

 productive structure of the well-cultivated soil. 



Stubble land is not only cut and inverted by real- 

 tillage, but is usually pulverized to the desired texture 

 much more extensively than is virgin land. Theoreti- 

 cally the pseudo-tillage need not, therefore, be quite so 

 intense to produce the proper tilth, although in prac- 

 tice it can hardly be overdone. On land often plowed 

 before, real-tillage, theoretically, should produce even 

 greater pulverization than on the other two kinds of 

 land. But, as a matter of fact, many such soils have 

 been so repeatedly cultivated that they require pro- 

 gressively deeper plowing and intensive pseudo-culti- 

 vation in order to maintain the standard of good 

 tilth. 



Pseudo-tillage consists mainly of the operations of 



harrowing, rolling, 

 packing, clod-smash- 

 ing, weeding, and stir- 

 ring and pulverizing 

 the surface soil gen- 

 erally. The pulveriz- 

 ing function is the 

 main one in pseudo- 

 tillage as it tends to 

 improve ventilation 

 and moisture-conser- 

 vation. The rolling and packing function is perhaps next 

 in importance and it is especially important in the drier 

 localities from the standpoint of moisture-conservation. 

 In accordance with the above, then, the plow is the 

 basic tillage tool and is the sole implement used in the 

 first type of tillage, while the several forms of surface 

 cultivators, including harrows, weeders, rollers, pack- 

 ers, cultivators, scarifiers, and pulverizers, constitute 

 the list of machines used in pseudo-tillage. 



The moldboard plow (Figs. 2245-2251). 



The plow, without question, stands first among 

 tillage implements. Historically it is probably one of 

 the oldest of farm implements and from the standpoint 

 of evolution its advance has been slow and its changes 

 profound. 



The evolution of the plow is here quoted from Davidson and 

 Chase "Farm Machinery and Farm Motors," New York and Lon- 



2247. The perfected American plow. 



