WHEAT SOILS OF Till-. .\IJ:X A .\ DR I A 1)|\IS1<).\. JJi) 



hut pliosphates are sorely lackinj^ in Ijotli .•-oils. The snil is said 

 to be acid in parts, and hence the addition of basic slag is highly 

 desirable, at the same time, to neutralise the acidity in the soil 

 c.nd to supply the much-needed phosphate. To provide against 

 potash exhaustion it would also l)e advisable to add kraal manure, 

 wool washings, or leaf ash, as procurable. 



Xos. 15 and 16 represent soils of medium class, of which 

 No. 16 — the virgin soil — is definitely the better, No. 15 having 

 undergone partial exhaustion by cultivation. There is still a fair 

 iuuount of nitrogen in the soil, but half the amount formerly there 

 has gone — judging from a comparison between Nos. 15 and 16. 

 Lime has diminished to about one-third of its original priipor- 

 tion, potash has decreased by one-fifth, and even the small i(uan- 

 tity of phosphatic material, once present, has sufifered reduction. 

 Xo. 15 is the lightest-coloured soil of the entire series, No. 16 

 Ijeing much darker brown, resembling Nos. iq and 20. All- 

 round manuring is really what such a soil needs, and phosphates 

 i;i particular. 



Nos. 17 and 18 are both poor in potash, and exceedingly poor 

 m phosphates, and should, therefore, be well supplied with fer- 

 tilisers containing these elements of plant food. In fact, these 

 are about the poorest soils of the entire series, and, while they 

 need potash and phosphatic material primarily, the application 

 of complete, i.e.. all-round, fertilisers is desirable. These soils 

 are more deficient in plant food generally than Nos. 10 and 9, 

 which they also resemble in their ]ihysical composition, 1)eing, 

 however, a little darker in colour. 



Nos. 19 and 20 are brown sandy loams rich in lime. They 

 contain fair amounts of potash and ]ihos])horic oxide, but could 

 very well be supplied with more. 



Plant Food Lost by Cultivation. 



Comparing the various cultivated with the corresponding 

 virgin soils, it is interesting to observe in how many cases cultiva- 

 tion has spelt, at all events, partial exhaustion for the soil, and 

 it will have been noted that throughout the series of soils sampled 

 there has been nothing in the way of replenishing the soils — 

 originally poor as many of them were, particularly in phosphates, 

 and further depleted by cultivation — with fertilisers. The 

 j.mounts removed from the soil have been calculated by com- 

 pearing the analyses of the cultivated soils with those of the 

 virgin soils, and, taking the weight of an average sandy loam 

 at 3>< million pounds per acre-foot (Hilgard "Soils," p. 107), 

 ^^. is estimated that the fohowing quantities have been removed 

 (luring the course of cultivation* from every acre of soil, to a 

 depth of one foot, of the various localities indicated: — 



*This remark obviously cannot apply where the virgin sample and 

 that of the cultivated soil do not fully correspond, e.g., with regard to the- 



lime content of Nos. 7 and 8. 



