Wheat and its Cultivation. 327 



nitrification goes on rapidly in well-tilled bare fallows under 

 Victorian conditions. The rate of nitrification under Victorian condi- 

 tions has not yet been completely worked out, but, -^wing to the high 

 soil-temperature during summer, it is fairly rapid i.i the well-tilled 

 bare fallows. In addition to the increase in nitrates, there can be 

 little doubt that other important plant foods, particularly potash and 

 phosphoric acid, are converted from unavailable to available forms. 

 " Subsidiary advantages of bare fallowing are that it cleans the 

 land of weeds, increases the amount of available plant food formed in 

 the soil, and enables a consolidated seed-bed to be formed." 



Liinitations of Bare Fallow. — " Obviously the most serious draw- 

 back to bare fallowing is that only one crop can be grown in two 

 years, and the crop must be debited with two years' rental value of 

 the land. A continual alternation of wheat and bare fallow must 

 ultimately lead to the depletion of the organic content of the soil. 

 As a permanent practice it is, therefore, inadequate." 



When to Fallow : Early versus Late Fallowing. — " The general 

 advantage of early fallow is that it exposes the soil to the amelio- 

 rating influences of the atmosphere for a longer period than late 

 fallow, and that heavy winter rains readily penetrate the sub-soil 

 and are conserved. Moreover, it is easier to effect a satisfactory 

 consolidation of tlie seed-bed with early than with late fallowed land. 

 With late spring fallowing much of the winter rain may be lost by 

 evaporation and surface drainage, and the main benefit accruing 

 from fallowing thereby lost. The practice of early autumn discing 

 as a preparation for winter ploughing is frequently adopted in the 

 drier areas with very satisfactory results. The practical difficulty 

 in carrying out this process is that in many parts of the State the soil 

 sets so hard in the dry summer weather that discing is precluded. 

 Otherwise there is no reason why the operation should not be com- 

 menced as soon after harvest as possible." 



Above shows clearly bow the value of fallowing in Victoria is recog-nizeil, and liow the 

 adoption of it has become almost general in dry areas. In the south-westein wheat areas of 

 the Cape the value of fallowing in principle is recognized inasmuch as farmers usually "braak" 

 their lands, in preparation for wheat ; i.e. in the preparation of land which has been grazed 

 for one or more years, the custom is to plough the lands deeply in July and August, and 

 plough only three or four inches deep at seeding time. An experiment commenced in 1915 at 

 Elfenburg tends to support this practice of " braaking." In this experiment five plots are 

 braaked against five jilots in which a cro^) of vetches is ploughed in as green manure in one 

 season, followed in the next season liy the planting of a cereal in the whole ten i)]ots. The 

 results to date are : — 



1916. — The plots which had been fallowed or braaked in the previous year gave 



I.o8 IV). of oats more per acre than the plots which bad been green manured. 

 1918. — The plots which had been fallowed or braaked in the previous year gave 

 210 lb. of wheat more per acre than the plots which had Vieen green manured. 



Depth of Working. — " Obviously deep working would be quite 

 undesirable wherever ihe soil was shallow, or where it rested on an 

 inferior type of sub-soil. It is also very undesirable to bring a crude, 

 raw clay sub-soil to the surface. On soils that are naturally deep, 

 however, it is well to give', wherever possible, a good stiff furrow. 

 Provided that the soil is of sufficient depth, and the sub-soil is satis- 

 factory, deep working is better suited to the requirements of an arid 

 climate than shallow working. Wherever deep working is practised, 

 it is necessary, if wheat is to be sown, that the ploughing should be 

 done many months before seeding. No plant suffers more from the 



