318 



Agricultural Gazette of N.S. W. 



[May 3, 1920. 





Oil Improvement for Maize, 



I. — Manures and Fertilisers. 



[Continued from page 183.] 



H. WENHOLZ, B.Sc. (Agr.), Inspector of Ajjricixlture. 



Potash. 



As has been shown, the demand of the maize crop on the ]5otash of the soil 

 is not particularly heavy, as most of this ingredient taken up by the plant 

 is returned to the soil in the stalks and leaves when ploughed in or burnt . 

 It is also a noteworthy fact that the subsoil generally contains a higher 

 percentage of potash than the surface soil. By the decay of deep-rooting 

 legumes or the manure from stock grazing such crops, this supply of potash 

 can in part be brought to the surface soil, where it can be made use of by 

 shallower rooting crops like maize. Mo.st things considered, it seems that 

 it is not essential to purchase potash in the form of chemical fertilisers for 

 maize or for most niaize soils, though in the case of some sandy loams markedly 

 deficient in easily available potash this ingredient may require to be bought 

 in small amounts for the maize crop. On reclaimed peaty swamp lands 

 (excellent for naaize-growing as a rule) the application of potash fertiliser is 

 oft n necessary and highly profitable. The truth of this statement has been 

 sui3j)orted by both soil analysis and field experiments in Illinois, t where, it is 

 stated, potash has increased the yield of maize from 10 or 20 bushels 

 per acre to 50 or 60 bushels on thousands of acres of reclaimed swamp land. 



As the carbonic and organic acids which are set free on the decay of organic 

 matter have the power of releasing potash from its insoluble compounds in 

 the soil, it is thought that on most maize soils sufficient available potash for 

 the maize crop can be maintained by keeping up the supply of decaying 

 organic matter in the soil. When this organic matter is allowed to be 

 depleted, potash fertilisers may stimulate the growth of maize. 



The following results with potash fertilisers on maize have been obtained 

 in New South Wales : — 



*Po iiiixture consists of 1 cwt. Sujierphosplnte anil 1 cwt. Sulphate of Potash. 

 t Illinois Farmers' Institute Report, 1911. 



