326 Journal of the Department of agriculture. 



scarce and dear. To suit these circumstances, large areas are sown 

 under pioneer conditions of culture. Large areas under crop and 

 small average returns per acre are the rule. While it may be said 

 that continuous growing of wheat on the same land year after year 

 is not good practice, the results obtained in the Broadbalk field at 

 the Rothamsted Experiment Station show that it is possible. For 

 example, wlieat has been grown continuously in the Broadbalk field 

 for over 60 years. The highest yield was obtained from Plot 8, viz., 

 oT.l bushels per acre; but in order to secure this result a liberal 

 dressing of nitrogenous phosphatic and potassic manures was applied 

 each year. Continuous cropping has been practised at Eoseworthy 

 College (South Australia) on seven dift'erent plots in the Permanent 

 Experimental Field. The results are highly interesting, and indicate 

 what is likely to take place in districts with a similar rainfall (17 

 inches). 



" The plots which had been bare fallowed the previous year gave 

 11 bushels in the second year and 12 bushels in the third year more 

 than plots on which the wheat was grown continuously. Moreover, 

 since the yields in the continuously cropped plots decreased from 29 

 bushels to 4 bushels in two years, it is obvious that these plots were 

 rapidly reaching the condition known as ' worn out,' and would 

 need a long period of rest before again giving a profitable return." 

 With regard to the main wheat areas of South Africa, fanners know from long experience 

 that continuous cropping with wheat is not advisable, and they havefoundit iiecesjary toallow 

 the land to recui)erate \>y leaving it fallow for two or more years. 



Wheat after Bare Falloto [Braak]. — " Bare fallowing is the most 

 popular method of preparation for wheat in all but the most humid 

 portions of the State. The fact that the area under bare fallow in 

 this State annually exceeds 1,000,000 acres is a silent testimony to the 

 effectiveness of this mode of cultivation under the conditions prevail- 

 ing in the wheat areas." 



Bare Fallowing conserves the Soil Moisture. — " In the drier 

 districts the rainfall during the growing period is not sufficient to 

 ensure high yields, but, by a good system of bare fallowing, a con- 

 sideiable proportion of the rainfall from the previous year is 

 conserved and carried over to augment the supply which falls during 

 the period of growth of the crop." 



The summary of Mr. Richardson's statement shows that to obtain the maximum results 

 from bare fallowing, certain principles must be complied with — 



(a) Every facility must be given to allow the moisture that falls to penetrate the soil. 

 This is obtained by keeping a loose broken surface, especially during the fallowing. 

 If the crop be grown on stubble lands, the breaking of the surface by using a one- 

 way disc cultivator or j)lough to the depth of three or four inches will promote 

 the absorption of rain. 

 (J) The soil must be so worked as to allow free capillary movement of the soil water. 

 A finely divided and firmly consolidated stratum of soil resting on the well- 

 moistened sub-soil is in the very best condition not only for the storage of moisture, 

 but for the movement of that moisture upward by capillary action. 

 {<■) The moisture nnist be prevented from evaporating at the surface. This is Ijrought 

 about by maintaining a mulch which should be loose but not overfine. 



Bare Falloiuing increases the Supply of Available Plant Food. — 

 " One indirect result of the moisture c(mserved by the process of bare 

 fallowing is that during the summer months many chemical and 

 biological changes take place within the body of the soil and result 

 in the liberation of plant food. There is no doubt that the process of 



