KARROO SOIL, LUCERNE AND THE OSTRICH. I25 



soil well supplied with all the essential constituents of plant 

 food. The air-day Mimosa wood* consists of: — 

 Moisture .. .. .. 7*65 % 



Organic constituents .. 88*25 % 



Ash 4-09 % 



And again the ashes contain : — 



Silica . . . . . . . . 5-21 % 



Oxide of Iron .. .. 13-78% 



Calcic Oxide .. .. .. 31 "85% 



Magnesic Oxide .. .. 10-36% 



Potassic Oxide .. .. 22-66% 



Phosphoric Oxide . . . . 5 -39 % 



These figures show that the Mimosa is a lime and potashi 

 eater of the first order, that it can thrive only on a rich 

 calcareous soil, and that the ashes of the Mimosa wood are 

 an excellent fertiliser for flower and vegetable gardening. 



The productive power of the Karroo soil is known through- 

 out South Africa, and does not require further comments. It 

 is the ideal soil for such crops as lucerne, which demand a 

 deep, loose soil with a large supply of lime, potash and phos- 

 phoric oxide. 



This is well illustrated by the following figures compiled 

 from " Chemie der Pflanzen," by Ebermayer. 



From one acre of land the quantities stated below are taken: 

 on an average by one crop of each of the following plants: — 

 Phosphoric Oxide. Calcic Oxide. Potassic Oxide. 



Lucerne .. 39 lbs. 186 lbs. 108 lbs. 



Tobacco .. .. 30 ,, 121 ,, 65 ,, 



Potatoes .. 29 ,, 31 ,, no ,, 



Peas . . . . 22 .. 39 .. 47 .. 



^^^leat .... 21 ,, 8 ,, 32 ,, 



Surely such facts must convince us that it is futile tO' 

 attempt the cultivation of lucerne on the sour, stifif clay soils- 

 of the coast districts of the Western Province without pre- 

 viously transforming them by "liming" into a suitable soil 

 for lucerne. 



In addition to the valuable mineral ingredients, lucerne 

 contains also a large proportion of albuminous compounds 

 and fat. Of all the fodder plants which we cultivate, lucerne- 

 contains the largest proportion of albuminous constituents, 

 and it is worth remembering that one pound of lucerne hay con- 

 tains more albuminous compounds than one pound of fresh- 

 fowl eggs. It is therefore a bone and muscle producer, which 

 has not its equal among the fodder crops which we cultivate- 

 for green and stable feeding. 



The lucerne also contains fat. which has a sweet, pleasant, 

 honey-like smell. This fat is uniformly distributed throughout 

 the system of the whole plant, and not limited to the leaves 

 or flowers; it can be extracted from the stalks as well as from 

 the leaves and flowers. 



* Most of the analyses given in this paper were made by the late 

 Donald Stevenson, son of Sir Edmund Stevenson, M.D. Mr. Stevenson had 

 devoted nearhr i8 months to the investigations which he hoped to embody 

 in a paper, which he intended reading at the meeting of the South African 

 Association for the Advancement of Science this year. I deeply lament the 

 untimely death of my young friend and assistant, whose work is of such 

 importance that it should be made known. I hope that it will be continued 

 by other students of Bio-Chemistry, who will follow up this work with the 

 same enthusiasm and devotion as our departed friend. 



