8 March, 1907.] Tlic Outlook for Agriculture. 133 



it is more valuable than ever. Similar instances could be quoted from 

 everv part of the State. 



Reverting to the total weight of each ingredient [)resent in the surface 

 foot of each acre, it will be seen that rich soils contain in this amount 

 of soil 3f tons of nitrogen. 3 tons of phosphoric acid, and 8J tons 

 ■of potash. One of the poorest contains i ton of nitrogen, 6 cwt. of 

 phosphoric acid, and 9 cwt. of potash. As a 20-bushel crop of wheat 

 (straw and grain) removes only 35 lbs. of nitrogen, 14 of phosphoric acid, 

 ^nd 25 of potash, it will be seen that even poor soil contains materials for 

 generations of cropping if the proper ingredients can only be made avail- 

 able. The phosphoric acid would last about 48 years. There is, how- 

 ever, the sub.soil to draw on, and we have seen that phosphoric acid is nearlv 

 as abundant in the subsoil as in the .surface. With intelligent farming 

 there is no question but that the amount of plant food will st(\a(lilv in 

 crease. The striking results produced by the application ^J. 10 lbs. of 

 phosphoric acid in the form of superphosphate have been already referred 

 to Such a small amount (\innot perceptibly increase the total' per acre. 

 At the most, it can only give the young plants a good start, because from 

 what we know of the residual effects of such applications, it is fairly cer- 

 tain that the whole of the added phosphoric acid is not ab.sorbed bv 

 the growing crop. There must, therefore, be certain changes going 

 on in the soil during the growth of the crop which rapidly render 

 the latent plant food available. What these are we are not in a posi- 

 tion at present to state precisely. The marvellous growth that occurs 

 everywhere when the rain comes after a dry spell shows that there 

 are forces at work during the months of bright sunshine which are \ery 

 friendly to the husbandman. The fact that applications of nitrogen 

 actually reduce the yield in the northern plains contirms this, view. IMany 

 acres of the poor sandy soils within 20 miles of INIelbourne are bought and sold 

 at from j^20 to ^40 per acre, after they have been under cultivation for 

 a few years, and where such improvement is daily taking place it is certain 

 that it will follow on the same metlhods being apiplied tO' more remote dis- 

 tricts as population increases. The absence of land animals accounts at 

 once for the luxuriance of our primaeval forests and tihe scarcity of phos- 

 phoric acid on the surface of the soil. Had the herbivora been well re- 

 presented in the past thev would have destroyed the young trees and at 

 the same time have concentrated the vjlant food. The existence of den.se 

 forests proves that Victoria contains no barren land, for soil that will 

 produce such trees will most assuredly produce a bounteous harvest when 

 its forces are controlled by the intelligence of man. 



With regard to the relatively large amounts of potash and lime in the 

 northern soils in Victoria, these substances have been shown to have a very 

 important influence in a number of ways. First of all they favour the 

 growth of micro-organisms in the surface soil, and in this way lead to the 

 rapid oxidization of organic matter, and the consequent formation of 

 hiutmus. They have, therefore, a direct effect in rendering both tht^ nitro- 

 gen and phosphoric acid more readily available for the plants. A soil 

 well supplied with humus is in the best possible condition^ for maintaining 

 a proper amount of moisture in readily available form in its superficial 

 layers, and hence it follows that soils well supplied with lime and potash 

 are, in proportion to their rainfall, in a good position to have practically 

 the whole of the moisture available for the plants, fn the coastal districts 

 where the rainfall is heavier, and conse(]uently the amount of soluble 



