WATER SOILS. 



123 



Province. Descriptions and analyses of these samples, with a discus- 

 sion of their comparative agricultural value, are given. The average 

 composition of the soils examined is as follows: 



Average composition of v:e.stern Cape of Good Hope soils. 



a In soil passing 1 mm. sieve. 



"The soils of the George district are, generally speaking, poor in lime and phos- 

 phates, and on the whole contain a fair amount of potash, while they are rich in 

 nitrogen. The Knysna soils contain an even larger percentage of nitrogenous mate- 

 rial, but are poor in potash and phosphoric oxid, lime being little better. Coming 

 to Uniondale, there i^ also a general lack of lime, but potash and jahosphates are 

 present in fair quantity, together with a good percentage of nitrogen. The Oudt- 

 shoorn division shows a good quantity of lime and nitrogenous matter in the soil, 

 and is also fairly satisfactory as regards potash and phosphoric oxid." 



The behavior of ^vater-soluble phosphoric acid in the soil, M, 



Ullmann ( J.J.S. m Chem. Ztg., 2J^ {1900), No. 20, Bepert., ^y. 65; 

 Chem. Centbl., 1900^ /, No. 15, p. 830). — In experiments on this subject 

 it was found that the phosphoric acid of superphosphate applied as a 

 top-dressing circulated in the soil, but remained soluble in water for 

 months after application. The rapidity of reversion of course depends 

 upon the amount of lime, magnesia, iron oxid, alumina, etc., present, 

 but according to the author the rate of reversion in artificial soil mix- 

 tures may be misleading as to this action in natural soils. 



Cultivation and weeding, P. P. Deherain {Ann. Agron., 26 {1900), 

 No. 5, pp. 257-261). — Pot and field experiments made b}^ the author 

 showed no benefits resulting from the cultivation of bare soil as regards 

 moisture preservation by the formation of a top soil mulch. Irrigated 

 soils in vetch contained considerably larger percentages of soil mois- 

 ture than unirrigated soils in vetch, but both soils showed from 25 to 

 50 per cent less moisture than soils on which no plants whatever were 

 growing. Weeds allowed to grow in crops have an effect similar to 

 the vetch in evaporating .soil moisture. The author believes the results 

 of his experiments show that " cultivation " and "weeding" are words 

 of equal value, both being beneficial in preserving soil moisture in so 

 far as they destroy weeds. 



A new method for the mechanical analysis of soils, G. Scarlata 

 {Staz. Sper. Agr. ltal.,32 {1899), pp. 631^-637; ahs. hi Chem. Cenihl., 

 1900, I, No. 10, p. 571). — The apparatus used in the proposed method 

 consists of a narrow 500 cc. beaker having a siphon with stopcock on 



