370 



[June 1907. 



SCIENTIFIC AGRICULTURE. 



A Note on the System of Cutivation in Arid Districts. 



By 0. Drieberg, 



Of late a good deal has been heard about the Campbell system of soil 

 culture, or, as it is also called, " dry farming" or dry cultivation, and to many it 

 would appear that some startlingly new discovery has been made with referenc to 

 soil treatment. This is far from being the case, and indeed the so-called new method 

 of culture embodies nothing very novel. But to Mr. W. H. Campbell, of Lincoln, 

 Nebraska, must be allowed the credit of having brought the various means of con- 

 serving soil moisture and overcoming the difficulties of a scanty rainfall to a system, 

 and showing how this system could be applied with success, and be the means of 

 bringing large areas of land, hitherto practically valueless, under regular cultiva- 

 tion. Briefly stated, the object of the new system is to bring about a certain 

 mechanical condition in the soil which will favour the growth of crops in the driest 

 districts. This is accomplished first by deep cultivation so that the soil is loosened 

 to a considerable depth in order to receive rain water and carry it downwards to be 

 there stored as in a reservoir. Secondly by packing the lower surface soil so that it 

 may establish a good medium (between the surface and sub-soil) for drawing up the 

 water which was carried down. Thirdly, by preserving the upper 2 to 4 inches of 

 soil as a mulch, by frequent stirring so that the moisture drawn up from the subsoil 

 to the packed stratum may not rise to the surface and be dissipated as vapour. 



The importance of deep cultivation and mulching has long been recognised 

 by the practical agriculturist, while consolidation, when necessary has also been re- 

 sorted to but the combination of the three operations, and their reduction to a system 

 applicable to specially unfavourable natural conditions, is the merit of the new 

 cultivation. The consolidation of the lower surface soil is not the least im- 

 portant of the three operations, and requires some care since it is not always satis- 

 factorily brought about by any of the ordinary farm implements. A special imple- 

 ment has been constructed to meet the case, called the " subsurface packer," which 

 is particularly useful where sowing is to shortly follow ploughing. But where an 

 interval is allowed to lapse between the two operations, the necessary consolidation 

 generally take place by the natural setting down of the soil, and also by the action 

 of rain, and a satisfactory seed bed is thus secured. Often, however, good ploughing 

 with a proper use of the harrow will bring out the results aimed at by the Campbell 

 system. It has been found that deep ploughing not only admits the water that falls 

 on the surface, but increases the area over which the soil bacteria work, so that by 

 this means a greater depth of good soil is secured. Of course, a sandy soil will 

 require less deep and less frequent ploughing than a heavy one. The loose surface 

 layer of soil should never be allowed to settle down, but must be preserved as such by 

 frequent stirring with suitable implements or by hand in preparing the land, while the 

 crop is growing, and even after it has been harvested. Thus is the soil kept continually 

 in a condition that not only prevents the loss of water already stored in the soil, but 

 also helps the absorption of rain by preventing its loss through surface drainage. 



According to the Campbell system, the land left uncultivated should not 

 be allowed to grow weeds or the surface to become crusted. In other words it 

 should be left in bare fallow. The more serious the drought, the more frequent 

 shoud be the loosening of the surface layer. This top layer should serve as a covering, 

 and if it answers its purpose, and the proper texture of the soil below it has been 

 secured, then the firm under layer should always have a supply of moisture from 

 beneath. Some people will object to the absence of weeds which are generally 



