5t) THE farmers' handbook. 



If it is necessary to use this class of water for irrigation, the following- 

 precautions must be taken : — 



The land must be efficiently drained if there is no natural run-off for the 

 water; the water must be run on in channels and cross-furrows, so that it 

 penetrates the soil laterally; it must be used in moderation, and not allowed 

 to lie on the surface; the surface soil should be continually cultivated with 

 the harrow, and, if possible, kept well mulched with vegetable matter. 



Of the substances recommended to neutralise the effect of alkali, gypsum 

 (sulphate of lime), in the form of powder, was first suggested by Professor 

 Hilgard for the alkali lands in the United States, and has been found suc- 

 cessful. Its use has not been adopted locally to any extent, but there can be 

 no doubt that it would be effective. It can be applied either directly to the 

 land itself, or placed in the channels or flumes so that the water has to pass 

 over it. 



The use of nitric acid has also been suggested; but, unfortunately, the 

 results of the experiments so far carried out locally have not been very 

 definite. The application of an acid naturally suggests itself as the most 



/ « 







Li . ..,, -. 



The "bare patch" terminates abruptly at the boundary of the plot to which superphosphate has been applied. 



obvious means of neutralising an alkaline substance, and nitric acid has the 

 additional advantage that it converts the injurious carbonate of soda into a 

 valuable fertiliser — nitrate of soda. Experiments reported by the Queens- 

 land Department of Agriculture indicate that it can be applied with benefit 

 to the bore water in proportions which will depend upon the amount of alkali 

 in the water. 



Common Salt (Sodium chloride). 



Except in the case of bore water, where its presence no doubt increases 

 the injury done by the alkali, but where its power for evil is insignificant in 

 comparison with that of carbonate of soda, common salt is hardly ever met 

 with in our soils, other than those close to the sea or salt-water creeks, and 

 liable to flooding. Crops vary considerably in regard to their power of 

 tolerating the presence of common salt. Some plants, such as beetroot and 



